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Human Exposure and Atmospheric Sciences Division Publications: 2004
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This page lists publication titles, citations and abstracts produced by NERL's Human Exposure and Atmospheric Sciences Division for the year 2004, organized by Publication Type. Your search has returned
198 Matching Entries.
See also Human Exposure and Atmospheric Sciences Division citations with abstracts:
1999,
2000,
2001,
2002,
2003,
2004,
2005,
2006,
2007,
2008
Technical Information Manager: Liz Hope - (919) 541-2785 or hope.elizabeth@epa.gov
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Presented/Published |
| BOOK CHAPTER |
Residential Post-Application Exposure Monitoring |
12/01/2004
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Lewis, R. G. Residential Post-Application Exposure Monitoring. Chapter 3, J. P. Worgan and C. A. Franklin (ed.), Occupational and Incidental Residential Exposure Assessment. John Wiley & Sons, Ltd., Chichester, Uk, 71-128, (2004).
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Methods of measurement of pesticide exposures can be separated into two categories: direct and indirect (Briston et al., 1984, Nigg et al. 1990). Direct methods measure a pesticide residue in environmental media or on the skin surface before it has entered the body in order to estimate the potential dose. Indirect methods estimate the minimum absorbed dose by measuring residues in excreta, body fluids, or tissue after exposure has occurred. Examples of direct methods are those that determine residues in the air, water, on surfaces, and in food. Indirect methods may involve determination of the levels of specific pesticides, their metabolites, or biological indicators (biomarkers), such as a protein- or DNA-adducts, in blood, urine, feces, sputum, sebum, cerumen, or adipose tissue. This chapter covers direct measurement methods only.
This product is a book chapter published December 1, 2004. CITATION: Lewis, R.G. Residential Post-Application Exposure Monitoring. Chapter 3, J.P. Worgan and C.A. Franklin (ed.), Occupational and Incidental Residential Exposure Assessment. John Wiley & Sons, Ltd., Chichester, UK, 71-128, (2004).
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Stochastic Human Exposure and Dose Simulation Model for the Wood Preservative Scenario (Sheds-Wood), Version 2 Model Sas Code |
04/09/2004
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XUE, J. AND G. GLEN. Stochastic Human Exposure and Dose Simulation Model for the Wood Preservative Scenario (Sheds-Wood), Version 2 Model Sas Code. U.S. Environmental Protection Agency, Washington, DC, EPA/600/C-04/104, 2004.
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Concerns have been raised regarding the safety of young children contacting arsenic and chromium residues while playing on and around Chromated Copper Arsenate (CCA) treated wood playground structures and decks. Although CCA registrants voluntarily canceled treated wood for residential use effective December 31, 2003, the potential for exposure from existing treated wood structures and surrounding soil still poses child health hazard concerns.
The EPA's Office of Research and Development (ORD), National Exposure Research Laboratory (NERL) collaborated closely with the EPA's Office of Prevention, Pesticides, and Toxic Substances (OPPTS), Office of Pesticide Programs (OPP) to conduct a probabilistic exposure assessment for children in the United States who frequently contact treated wood playsets and decks in public and residential locations. NERL's probabilistic Stochastic Human Exposure and Dose Simulation model for wood preservatives (SHEDS-Wood) was developed and applied to estimate children's absorbed dose of the arsenic and hexavalent chromium components of CCA. ORD's exposure assessment was used by OPP to help determine the potential short-term, intermediate-term, and lifetime cancer risks for the population of interest.
Skin contact with, and ingestion of, arsenic and chromium in soil and wood residues were considered for a population of children simulated by SHEDS-Wood using EPA's Consolidated Human Activity Database (CHAD). Model analyses were conducted to assess the range and uncertainty in population estimates, key model inputs, and the impact of various potential mitigation strategies such as the use of sealants and hand washing after play events. Draft reports for the exposure and risk assessments can be found on the EPA website for the December 3-5, 2003 Scientific Advisory Panel meeting: www.epa.gov/scipoly/sap.
OPP's Reregistration Eligibility Decision (RED) document for Chromated Arsenicals will include a comprehensive assessment of the potential impacts of CCA on human health and the environment. It is anticipated that the outcome of OPP/ORD human health risk assessment will be pivotal in the risk management and reregistration eligibility decisions for CCA, and in advising the public how to minimize health risks from existing treated wood structures
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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Aerosol Inorganics and Organics Model (Aiom) With User Defined Properties for Organic Compounds |
09/01/2004
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Clegg, S. L. AND E. O. Edney. Aerosol Inorganics and Organics Model (Aiom) With User Defined Properties for Organic Compounds. U.S. Environmental Protection Agency, Washington, DC, EPA/600/C-04/105, 2004.
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The Aerosol Inorganics Model (AIM) is widely used to calculate gas/liquid/solid phase equilibrium in aerosol systems containing the species H+-NH4+-SO42--NO3--H2O over a range of tropospheric temperatures. In this internal report the model is extended to include organic compounds in order to treat the behavior and interactions of the organic component of PM2.5. This report describes the extension of the AIM model, using the method of Clegg to include an arbitrary number of aerosol organic compounds. These compounds have thermodynamic properties defined by the user and can partition between gas, aqueous, solid, mixed solid, and separate organic-water phases. The organic compounds can also dissociate (to produce H+ ion) in the liquid phase(s). In this report the underlying theory of the extended model is described, followed by its capabilities and features, and then instructions on how it is used. Also included are diskettes containing the executable code for the completed model, and a secondary executable code for fitting activity data for organic-water solutions.
The United States Environmental Protection Agency through its Office of Research and Development partially funded and collaborated in the research described here under contracts 68D-00206 to ManTech Environmental Technology, Inc. and 3D-5095-NAEX to the University of East Anglia. It has been subjected to Agency review and approved for dissemination.
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An Environmental Technology Verification (Etv) Performance Testing of Three Rapid Pcr Technologies for Idaho Technology R.A.I.D.® System, Applied Biosystems Taqman® E. Coli 0157:H7 Detection System, and Invitrogen Corporation Pathalerttm Detection Kits |
12/15/2004
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RIGGS, K. An Environmental Technology Verification (Etv) Performance Testing of Three Rapid Pcr Technologies for Idaho Technology R.A.I.D.® System, Applied Biosystems Taqman® E. Coli 0157:H7 Detection System, and Invitrogen Corporation Pathalerttm Detection Kits. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/026, 2004.
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The Environmental Technology Verification (ETV) Program, beginning as an initiative of the U.S. Environmental Protection Agency (EPA) in 1995, verifies the performance of commercially available, innovative technologies that can be used to measure environmental quality. The ETV provides, through a third-party, quality-assured performance data so buyers and users of environmental technologies can make informed purchase and application decisions, thus providing one path to reducing emissions and improving human health. To provide cost-effective testing, Stakeholder committees, made up of members with diverse backgrounds, provide guidance to the ETV by identifying and prioritizing environmental technologies to address present day environmental quality challenges.
The ETV Advanced Monitoring Systems (AMS) Center, one of six ETV Centers, is actively involved in verifying the performance of advanced monitoring systems available to the public for purchase. The AMS Center participates in the mission of the ETV by providing Test Plans, Protocols, conducting independent performance tests of technologies, and preparing Verification Reports and Statements describing the results of the testing. Vendors of tested technologies can use the Verification Reports and Statements for marketing purposes. All approved Verification Reports are posted on the ETV Web Site as a form of distribution. The individual verification reports and statements describe by this abstract are for three Rapid Polymerase Chain Reaction (PCR) technologies: Idaho Technology R.A.P.I.D®. System, Applied Biosystems Taqman® E. Coli 0157:H7 Detection System, and Invitrogen Corporation PathAlert Detection Kits.
The purpose of this verification test of rapid PCR technologies was to evaluate the ability of these technologies to detect the presence of specific bacteria in water and to determine the technologies susceptibility to specific interferents added to pure water and to those interferents inherently present in several drinking water matrices. The technologies for this verification test operate based on the PCR process, which involves enzyme-mediated reactions that allow for target DNA (that from the bacteria of interest) replication and amplification through a series of temperature cycles. Before the target DNA can be amplified, however, it must first be extracted from the bacteria and then purified.
Because rapid PCR technologies are anticipated to serve mostly as screening tools in water monitoring scenarios, providing rapid results as to whether or not a pathogen or biological agent is present in the water, this verification test involved only qualitative results. This verification test of these technology systems were conducted according to procedures specified in the Test/QA Plan for Verification of Rapid PCR Technologies. The performance of these technologies system were verified in terms of the following parameters: accuracy, specificity, false positive/negative responses, precision, and interferences.
The performance of these technology systems were verified by subjecting them to various concentration levels of Bacillus anthracis (B. anthracis) Ames strain, Francisella tularensis (F. tularensis) LVS (ATCC# 29684), Yersinia pestis (Y. pestis) CO92, Brucella suis (ATCC#23444), and Escherichia coli O157:H7 (E. coli) in American Society of Testing and Materials (ASTM) Type II deionized (DI) water; ASTM Type II DI water spiked with various interferents; and concentrated drinking water (DW) samples obtained from four water utilities from different geographical locations in the United States. Each source of DW represented a unique water treatment process. In addition, the interferent and DW samples were analyzed without adding any contaminant to evaluate the potential for false positive results. These system were tested for one bacteria at a time and only for the bacteria it was capable of detecting.
Contaminant concentrations included the infective/lethal dose concentrations for each contaminant and approximately 2, 5, 10, and 50 times the vendor-reported limit of detection (LOD). The infective/lethal dose of each contaminant was determined by calculating the concentration at which 250 mL of water is likely to cause the death of a 70-kilogram person based on human LD50 or ID50 data.
For the purposes of this verification test, the LOD is anticipated to be the level at which quantifiably reproducible positive results are obtained. It represents the level for the entire system at which reproducible positive results are obtained from a raw water sample. As such, it is more of a method or experimental detection limit than a true instrument detection limit. This detection level, then, incorporates the sensitivities and uncertainties of the entire technology system, in particular the DNA purification step as well as additional reagents. Detection limits for individual components of these technology systems may differ and were not verified in this test.
The verification test was conducted at Battelle's Medical Research and Evaluation Facility in West Jefferson, Ohio, as well as Battelle headquarters in Columbus, Ohio, from May 27, 2004, through July 8, 2004. Aqua Tech Environmental Laboratories, Inc. (ATEL) of Marion, Ohio, performed physicochemical characterization for each DW sample, including turbidity, dissolved and total organic carbon, specific conductivity, alkalinity, pH, magnesium (Mg), calcium (Ca), hardness, total organic halides, trihalomethanes, and haloacetic acids.
QA oversight of the verification testing was provided by the EPA and Battelle. Battelle QA staff conducted a technical systems audit and a data quality audit of 10% of the test data. The verification statement, the full report on which it is based, and the test/QA plan for this verification are all available at http://www.epa.gov/etv/centers/center1.html.
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| JOURNAL |
Developing Meaningful Cohorts for Human Exposure Models |
01/01/2004
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Graham, S. E. AND T. R. McCurdy. Developing Meaningful Cohorts for Human Exposure Models. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY 14(1):23-43, (2004).
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This paper summarizes numerous statistical analyses focused on the U.S. Environmental Protection Agency's Consolidated Human Activity Database (CHAD), used by many exposure modelers as the basis for data on what people do and where they spend their time. In doing so, modelers tend to divide the total population being analyzed into "cohorts", to reduce extraneous inter-individual variability by focusing on people with common characteristics. Age and gender are typically used as the primary cohort defining-attributes, but more complex exposure models also use weather, day-of-the-week, and employment attributes for this purpose. We analyzed all of these attributes and others to determine if statistically significant differences exist among them to warrant their being used to define distinct cohort groups. We focused our attention mostly on the relationship between cohort attributes and the time spent outdoors, indoors, and in motor vehicles. Our results indicate that besides age and gender, other important attributes for defining cohorts are the physical activity level of individuals, weather factors such as daily maximum temperature in combination with months of the year, and combined weekday/weekend with employment status. Less important are precipitation and ethnic data. While statistically significant, the collective set of attributes does not explain a large amount of variance in outdoor, indoor, or in-vehicle locational decisions. Based on other research, parameters such as lifestyle and life stages that are absent from CHAD might have reduced the amount of unexplained variance. At this time, we recommend that exposure modelers use age and gender as "first order" attributes to define cohorts followed with physical activity level, daily maximum temperature or other suitable weather parameter, and day-type possibly beyond a simple weekday/weekend classification.
This work has been funded wholly by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication. Mention of trade names of commercial products does not constitute an endorsement or recommendation for use.
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Preparation and Characterization of Molecularly Imprinted Electropolymerized Carbon Electrodes |
01/09/2004
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Weetall, H. AND K. R. Rogers. Preparation and Characterization of Molecularly Imprinted Electropolymerized Carbon Electrodes. TALANTA 62(1):329-335, (2004).
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Molecularly imprinted polymers (MIP) selective for fluorescein, rhodamine or 2,4-dichlorophenoxyacetic acid (2,4-D) were electropolymerized onto graphite electrodes using an aqueous solution equimolar in resorsinol/ortho-phenylenediamine and in the presence of the template molecule. For the dyes, the MIP-coated electrodes showed higher affinity for their template molecule than for a non-template dye. The 2,4-D-MIP-coated electrode showed a concentration dependent response for 2,4-D as compared to the polymer-coated electrode prepared in the absence of template molecule.
The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), has funded and performed the research described. This manuscript has been subjected to the EPA's peer and administrative review and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation by the US EPA.
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Preface: Special Issue of Aerosol Science and Technology on Findings from the Fine Particulate Matter Supersites Program |
04/20/2004
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Solomon, P. A. AND D. Allen. Preface: Special Issue of Aerosol Science and Technology on Findings from the Fine Particulate Matter Supersites Program. AEROSOL SCIENCE AND TECHNOLOGY 38(S1):1-4, (2004).
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This collection of papers, which is the first coordinated publication of results from the Phase II Supersites Program, reflects the objectives of the program - to characterize particulate matter, to provide information, such as source-receptor relationships, that support health effects and exposure research, and to develop new methods for characterizing fine particulate matter. Reports describe results from Supersites projects in Houston TX, Los Angeles CA, New York NY, Pittsburgh PA, and from sites in the southern US that were associated with the Atlanta Supersites project. A Phase I Supersites Program special issue describing results from Atlanta has been published (Solomon et al., 2003). Additional coordinated publication of research results is planned, so that the community interested in airborne PM can effectively monitor the advances in understanding PM made through the Supersites Program. The next special issue is underway in Atmospheric Environment with publication anticipated in mid-2004 followed by a special issue in the Journal of Geophysical Research - Atmospheres in early 2005. Subsequent second special issues are anticipated in each of these journals during 2005 and 2006.
The United States Environmental Protection Agency through its Office of Research and Development partially funded and collaborated in the research described here under Assistance agreement Nos. CR828057-01 (Desert Research Institute, Reno, NV), CR80858-01-0 (Washington University, St. Louis, MO), CR80859-01-0 (University of California, Los Angeles, CA), CR80860-01-0 (State University of New York, New York, NY), CR80861-01-0 (Carnegie Mellon University, Pittsburgh, PA) CR80862-01-0 (University of Texas, Austin, TX), and CR80863-01-0 (University of Maryland, Baltimore, MD). It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by EPA.
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Reconstructing Population Exposures from Dose Biomarkers: Inhalation of Trichloroethylene (Tce) as a Case Study |
04/14/2004
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Sohn, M. D., T. E. McKone, AND J. N. Blancato. Reconstructing Population Exposures from Dose Biomarkers: Inhalation of Trichloroethylene (Tce) as a Case Study. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY 14(3):204-213, (2004).
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Physiologically based pharmacokinetic (PBPK) modeling is a well-established toxicological tool designed to relate exposure to a target tissue dose. The emergence of federal and state programs for environmental health tracking and the availability of exposure monitoring through biomarkers creates the opportunity to apply PBPK models to estimate exposures to environmental contaminants from urine, blood, and tissue samples. However, reconstructing exposures for large populations is complicated by often having too few biomarker samples, large uncertainties about exposures, and large interindividual variability. In this paper, we use an illustrative case study to identify some of these difficulties and for a process for confronting them by reconstructing population-scale exposures using Bayesian inference. The application consists of interpreting biomarker data from eight adult males with controlled chamber. We successfully reconstructed the exposure scenarios for both subgroups although the reconstruction of one subgroup is different than what is believed to be the true experimental conditions. We were however unable to predict with high certainty the concentration of TCE in air.
This work was supported in part by the US Environmental Protection Agency National Exposure Research Laboratory through Interagency Agreement #DW-988-38190-01-0 and carried out at Lawrence Berkley National Laboratory through the US Department of Energy under contract Grant No. DE-AC03-76SF00098. This work is also supported in part by the Health Tracking Center of Excellence at the University of California Berkley, and funded by interagency agreement No. U50CCUT922409-01 with US Centers for Disease Control.
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Field Method Comparison Between Passive Air Samplers and Continuous Monitors for Volatile Organic Compounds and NO2 in El Paso, Texas, USA |
03/01/2004
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Mukerjee, S., L. Smith, G. A. Norris, M. T. Morandi, M. Gonzales, C. A. Noble, L. Neas, AND A. H. Ozkaynak. Field Method Comparison Between Passive Air Samplers and Continuous Monitors for Volatile Organic Compounds and NO2 in El Paso, Texas, USA. JOURNAL OF AIR & WASTE MANAGEMENT ASSOCIATION 54(3):307-319, (2004).
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Passive sampling of gas-phase air toxics and criteria pollutants has become an attractive monitoring method in human exposure studies due to the relatively low sampling cost and ease of use. This study evaluates the performance of Model 3300 Ogawa(TM) Passive NO2 Samplers and 3M(TM) 3520 Organic Vapor Monitors (OVMs) by comparing the integrated passive sampling concentrations to averaged hourly NO2 and VOC measurements made at two continuous air monitoring stations (CAMS) operated by the Texas Commission on Environmental Quality (TCEQ) in the U.S.-Mexico border city of El Paso, Texas. Passive samplers were deployed over three time intervals (3 day weekend, 4 day weekday, and 7 day weekly) for three consecutive weeks, from November 29, 1999 through December 17, 1999. OVM concentrations were corrected for ambient pressure to account for the higher elevation in El Paso. Highly precise results (< 5 % relative standard deviation, RSD) were found for NO2 measurements from collocated Ogawa samplers. Reproducibility was lower from duplicate OVMs for the BTEX (benzene, toluene, ethylbenzene, and xylene isomers) VOC species (>/- 7 % RSD for 2 day samples) with better precision for longer sampling periods. Comparison of Ogawa N02 samplers with chemiluminescence measurements averaged over the same time period suggested potential calibration problems with the chemiluminescence analyzer at the sites, although further evaluation of the Ogawa sampler with continuous measurements was considered necessary. For the BTEX species compared, generally good agreement was obtained between OVMs and auto-GC measurements. The OVMs successfully tracked increasing levels of organic pollutants recorded by the continuous monitors. However, except for toluene, the OVM BTEX measurements generally exceeded their continuous counterparts with a mean bias ranging from 5-10 %. Although the interpretation of the study results was limited due to small sample sizes, diffusion barrier influences due to the design of the shelters, used to house the OVMs, and differences in sampling heights between OVMs and the auto-GC inlet may explain the over-estimation. This study demonstrates the need to perform additional evaluation of collocated passive samplers/with continuous monitors and/or other pumped sampling methods to further evaluate the precision and sampling rate.
The U.S. EPA through its Office of Research and Development funded and managed the research described here under contract 68-D-99-012 to Research Triangle Institute and contract 68-D0-0206 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
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Design and Sampling Methodology for a Large Study of Preschool Children's Aggregate Exposures to Persistent Organic Pollutants in Their Everyday Environments |
05/01/2004
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Wilson, N. K., J. C. Chuang, R. Iachan, C. Lyu, S. M. Gordon, M. K. Morgan, A. H. Ozkaynak, AND L. S. Sheldon. Design and Sampling Methodology for a Large Study of Preschool Children's Aggregate Exposures to Persistent Organic Pollutants in Their Everyday Environments. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY 14(3):260-274, (2004).
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Young children, because of their immaturity and their rapid development compared to adults, are considered to be more susceptible to the health effects of environmental pollutants. They are also more likely to be exposed to these pollutants, because of their continual exploration of their environments with all their senses. Although there has been increased emphasis in recent years in exposure research aimed at this specific susceptible population, there are still large gaps in the available data, especially in the area of chronic, low-level exposures of children in their home and school environments. A research program on preschool children's exposures was established in 1996 at the USEPA National Exposure Research Laboratory. The emphasis of this program is on children's aggregate exposures to common contaminants in their everyday environments, from multiple media, through all routes of exposure. The current research project, "Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants," (CTEPP), is a pilot-scale study of the exposures of 257 children, ages 18 months to 5 years, and their primary adult caregivers to contaminants in their everyday surroundings. The contaminants of interest include several pesticides, phenols, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and phthalate esters. Field recruitment and data collection began in February 2000 in North Carolina and were completed in November 2001 in Ohio. This paper describes the design strategy, survey sampling, recruiting, and field methods for the CTEPP study.
The United States Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under contract #68-D99-011 to Battelle. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
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Wind Tunnel Evaluation of An Aircraft-Borne Sampling System |
04/01/2004
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Irshrad, H., A. McFarland, M. S. Landis, AND R. K. STEVENS. Wind Tunnel Evaluation of An Aircraft-Borne Sampling System. AEROSOL SCIENCE AND TECHNOLOGY 38(4):311-321, (2004).
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The US Environmental Protection Agency (EPA), the Florida Department of Environmental Protection (FLDEP), and Texas A&M University collaborated in the design, construction, and testing of a unique highly cross-linked Teflon coated inlet and manifold gas and aerosol sampling system that are being used in EPA aircraft atmospheric pollution characterization studies. The aircraft-borne ambient sampling system consists of a Teflon coated shrouded probe coupled to a Teflon coated aluminum manifold that are designed to collect reactive gases (e.g., mercury and halide species) and aerosols for subsequent analysis and characterization. The shrouded inlet probe was tested for particle transmission ratios in a high-speed aerosol wind tunnel. An existing wind tunnel was upgraded from a maximum wind speed of 13.4 m/s (48 km/h or 30 miles/hr) to 50.5 m/s (182 km/h or 113 miles/hr) to test this probe. The wind tunnel was evaluated for compliance with the criteria of ANSI 13.1 to establish the acceptability of its use in testing probes. The results demonstrated that the velocity and tracer gas concentration profiles were within the specified limits. A well characterized ThermoAndersen Shrouded Probe (Model RF-2-112) was also tested to check tunnel performance and test methodology. The results obtained from these tests are in close agreement with data published earlier.
The aircraft-borne shrouded probe showed a transmission ratio of about 0.76 at 45 m/s (162 km/h or 100 miles/hr) for 10 m aerodynamic diameter particles at a sampling flow rate of 90 L/min. To improve the transmission ratio of the sampling probe, the sampling flow rate was reduced to 80 L/min and the air speed increased to 50.5 m/s, which increased the transmission ratio to about 0.9 for 10 m particles. Further reduction of the flow rate to 60 L/min increased the transmission to 1.2. The Teflon coated manifold downstream of the shrouded probe, was statically tested for transmission ratio at flow rates of 90 L/min and 30 L/min. The results were a transmission ratio about 0.80 for 10 m aerodynamic diameter particles. The combination of the shrouded probe operated at 60 L/min with a transmission ratio of 1.2 and the manifold with its transmission of 0.8, will give an overall transmission of about unity for 10 um aerodynamic diameter particles at a flight speed of 50.5 m/s.
These findings suggest that shrouded probes can be used for low speed (~100 miles/hr) aircraft applications. The transmission ratio of these probes is a significant improvement over the conventional aircraft-mounted, sharp-edged isokinetic diffuser-type inlets.
This manuscript has been subjected to Agency Review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
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Divalent Inorganic Reactive Gaseous Mercury Emissions from a Mercury Cell Chlor-Alkali Plant and Its Impact on Near Field Atmospheric Dry Deposition |
02/01/2004
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Landis, M. S., G. J. Keeler, K. I. AlWali, AND R. K. STEVENS. Divalent Inorganic Reactive Gaseous Mercury Emissions from a Mercury Cell Chlor-Alkali Plant and Its Impact on Near Field Atmospheric Dry Deposition. ATMOSPHERIC ENVIRONMENT 38(4):613-622, (2004).
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The emission of inorganic divalent reactive gaseous mercury (RGM) from a mercury cell chlor-alkali plant (MCCAP) cell building and the impact on near field (100 km) dry deposition was investigated as part of a larger collaborative study between EPA, University of Michigan, Oak Ridge National Laboratory, Chlorine Institute, and Olin Corporation in February 2000. Measurements in the cell building roof vent showed that RGM constituted 1.9 +/- 0.8% (mean +/- standard deviation) of the concurrently measured elemental gaseous mercury (Hg0). This relationship was used to calculate an estimated RGM emission rate from the cell building roof vent of 10.4 g day-1. The percentage of RGM/Hg0 at ambient monitoring sites 350 m (1.5%) and 800 m (1.3%) away while being impacted by cell building emissions suggests the rapid deposition of RGM species. The observed 2% relative emission of RGM/Hg0 was substantially lower than the 30% estimate utilized by EPA to model the impact of MCCAPs for the 1997 Mercury Report to Congress. However, the MCCAP was still found to present a significant impact on near field mercury atmospheric dry deposition. A Lagrangian transport and deposition modeling framework using only emissions from the MCCAP found the mean annualized dry deposition of mercury within a 10 km radius of the facility contributed the annual equivalent of 4.6 ug m-2. For comparison, the total annual wet mercury deposition measured at the Savannah River National Mercury Deposition Network sampling site ~30 km away was 9.8 ug m-2.
This work has been funded wholly or in part by the U.S. Environmental Protection Agency. It has been subjected to Agency Review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
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Concentrations and Solubility of Metals from Indoor and Personal Exposure PM2.5 Samples |
01/01/2004
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Graney, J. R., M. S. Landis, AND G. A. Norris. Concentrations and Solubility of Metals from Indoor and Personal Exposure PM2.5 Samples. ATMOSPHERIC ENVIRONMENT 38(2):237-247, (2004).
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An assessment of trace metal quantification capabilities for indoor (123 ± 53 μg; mean ± standard deviation of particle mass) and personal exposure (32 ± 12 μg) PM2.5 samples from Baltimore, MD was undertaken as part of an EPA study investigating health effects associated with particulate matter. This study included determination of total PM2.5 metal concentrations by energy dispersive x-ray fluorescence (XRF), instrumental neutron activation analysis (INAA), and method development to quantify amounts of water and acid extractable metals from PM2.5 using inductively coupled plasma-mass spectrometry (ICP-MS). Analytical uncertainties, filter blank contributions, and sample preparation were all found to significantly impact quantification limits. The ICP-MS leaching procedure resulted in partial extraction of metals from the PM2.5. Most of the extractable component of the metals was in a water-soluble form suggesting a high potential for bioavailability of elements from respiratory exposure to PM2.5. A comparison of PM2.5 trace metal concentrations from indoor air samples collected from a central indoor site versus concurrently collected personal exposure samples indicates that resident activities result in exposure to higher concentrations of soluble trace metals.
This work as been funded wholly or in part by the U.S. Environmental Protection Agency Office of Research and Development. It has been subjected to Agency Review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
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Identification of Possible Sources of Particulate Matter in the Personal Cloud Using Sem/Edx |
10/01/2004
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Conner, T. L. AND R. W. Williams. Identification of Possible Sources of Particulate Matter in the Personal Cloud Using Sem/Edx. ATMOSPHERIC ENVIRONMENT 38(31):5305-5310, (2004).
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The United States Environmental Protection Agency (U.S. EPA) conducted the Baltimore Particulate Matter (PM) Epidemiology-Exposure Study of the Elderly during the summer of 1998. The study design included PM2.5 samples obtained from elderly (65+ years of age) retirement facility residents using personal exposure sampling devices. These sampling devices were also used to obtain PM2.5 samples at fixed locations within the personal monitoring subjects' apartments. Selected personal and apartment samples were examined using scanning electron microscopy with individual-particle X-ray analysis (SEM/EDX), providing a qualitative assessment of the chemical and physical characteristics of geological and trace element particles collected within these micro-environments at the retirement facility. This information was used to identify possible indoor source particles. The manual surveys of the personal samples revealed that some particles larger than 2.5 um reached the filter surface. Using SEM/EDX , several particle types with possible indoor origins were identified. The Al-Zr-Cl particle is likely to have originated from a personal antiperspirant product. Particles with a talc or alumino-silicate composition point to cosmetics as a possible source. Large cadmium-containing particles were also found, which may indicate the use of art pigments or ceramic glazes, or emissions from television screen phosphors. A greater variety of particles was observed in a personal sample compared with its corresponding fixed-location apartment sample.
The United States Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under contract #68-D5-0040 to the Research Triangle Institute and contract #68-D5-0049 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication.
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| JOURNAL |
An Approach for Screening Cholinesterase Inhibitors in Drinking Water Using An Immobilized Enzyme Assay |
06/01/2004
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Weetall, H., N. N. Mishra, A. Mahfouz, AND K. R. Rogers. An Approach for Screening Cholinesterase Inhibitors in Drinking Water Using An Immobilized Enzyme Assay. ANALYTICAL LETTERS 37(7):1297-1305, (2004).
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A simple, inexpensive and sensitive method for detecting organophosphate and carbamate insecticides is reported. Acetylcholinesterase was immobilized to PorexR Lateral-FloTM membrane material and remained active for several months at room temperature. The assay was sensitive to a number of organophosphate and carbamate insecticides. Tap water and bottled water matrices showed no effect on the assay. The change in optical density could be determined using an optical plate reader or by visual examination compared to a control and blank. The detection limit for paraoxon by visual examination was 10 ppb.
The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), has funded and performed the research described. This manuscript has been subjected to the EPA's peer and administrative review and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation by the US EPA.
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| JOURNAL |
Effect of Central Fans and in-Duct Filters on Deposition Rates of Ultrafine and Fine Particles in An Occupied Townhouse |
01/01/2004
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Wallace, L. A., C. HowardReed, AND S. J. Emmerich. Effect of Central Fans and in-Duct Filters on Deposition Rates of Ultrafine and Fine Particles in An Occupied Townhouse. ATMOSPHERIC ENVIRONMENT 38(3):405-413, (2004).
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Airborne particles are implicated in morbidity and mortality of certain high-risk subpopulations. Exposure to particles occurs mostly indoors, where a main removal mechanism is deposition to surfaces. Deposition can be affected by the use of forced- air circulation through ducts or by air filters. In this study we calculate the deposition rates of particles in an occupied house due to forced-air circulation and the use of in-duct filters such as electrostatic precipitators (ESP) and fibrous mechanical filters (MECH). Deposition rates are calculated for 128 size categories ranging from 0.01 um to 2.5 um. More than 110 separate "events" (mostly cooking, candle burning, and pouring kitty litter) were used to calculate deposition rates for four conditions: fan off, fan on, MECH installed, ESP installed. For all cases, deposition rates varied in a "U"-shaped distribution with the minimum occurring near 0.1 um, as predicted by theory. The use of the central fan with no filter or with a standard furnace filter increased deposition rates by amounts on the order of 0.1 h-1 to 0.5 h-1. The MECH increased deposition rates by up to 2 h-1 for ultrafine and fine particles but was ineffective for particles in the 0.1 um to 0.5 um range. The ESP increased deposition rates by 2 h-1 to 3 h-1 and was effective for all sizes. However, the ESP lost efficiency after several weeks and needed regular cleaning to maintain its effectiveness. A reduction of particle levels by 50% or more could be achieved by use of the ESP when operating properly. Since the use of fans and filters reduces particle concentrations from both indoor and outdoor sources, it is more effective than the approach recommended by certain agencies of reducing ventilation by closing windows or insulating homes more tightly. For persons at risk, use of an air filter may be an effective method of reducing exposure to particles.
This study was partially funded by an EPA Internal Grant to the first author. It has been reviewed and cleared for publication. Certain commercial equipment, instruments, or materials are identified in this paper in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose.
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| JOURNAL |
Assaying Particle-Bound Polycyclic Aromatic Hydrocarbons (PAH) from Archived PM2.5 Filters |
04/09/2004
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Pleil, J. D., A. F. Vette, AND S. M. Rappaport. Assaying Particle-Bound Polycyclic Aromatic Hydrocarbons (PAH) from Archived PM2.5 Filters. JOURNAL OF CHROMATOGRAPHY A 1033(1):9-17, (2004).
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Airborne particulate matter contains numerous organic species, including several polycyclic aromatic hydrocarbons (PAHs) that are known or suspected carcinogens. Existing methods for measuring airborne PAHs are complex and costly, primarily because they are designed to collect both gas-phase and particle-phase PAH constituents. Here, we report an assay for measuring particle-bound PAHs in archived filters from the network of U.S. monitoring stations for particles less than 2.5 um in diameter (PM2.5), without the need for deploying specialized samplers. PAHs are extracted from Teflon filters with dichloromethane, concentrated, and measured at trace levels using gas-chromatography mass-spectrometry. Although PAHs with 3 to 6 aromatic rings can be assayed, results are only unambiguously accurate for compounds with 5- or 6-rings, due to variable vaporization losses of the more volatile 3- & 4-ring compounds during sampling and/or storage. The method was evaluated for sensitivity, recovery, precision, and agreement of paired air samples, using PM2.5 samplers deployed locally in Chapel Hill, NC. Additionally, three sets of archived samples were analyzed from a study of PM2.5 in the Czech Republic. Levels of some 4-ring and all 5- & 6- ring PAHs in both the local and Czech samples were consistent with published results from investigations employing PAH-specific air samplers. This work strongly suggests that assessment of particle-bound 5- & 6-ring PAHs from archived PM2.5 filters is quantitatively robust. The assay may also be useful for selected 4-ring compounds, notably chrysene and benzo(a)anthracene, if PM2.5 filters are stored under refrigeration.
The research has been subjected to (EPA) Agency review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| JOURNAL |
Estimating Contaminant Dose for Intermittent Dermal Contact: Model Development, Testing, and Application |
02/01/2004
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Riley, W. J., T. E. McKone, AND E. A. CohenHubal. Estimating Contaminant Dose for Intermittent Dermal Contact: Model Development, Testing, and Application. RISK ANALYSIS 24(1):73-85, (2004).
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Assessments of aggregate exposure to pesticides and other surface contamination in residential environments are often driven by assumptions about dermal contacts. Accurately predicting cumulative doses from realistic skin contact scenarios requires characterization of exposure scenarios, skin surface loading and unloading rates, and contaminant movement through the epidermis. In this paper we (1) develop and test a finite-difference model of contaminant transport through the epidermis; (2) develop archetypal exposure scenarios based on behavioral data to estimate characteristic loading and unloading rates; and (3) quantify 24-hour accumulation below the epidermis by applying a Monte Carlo simulation of these archetypal exposure scenarios. The numerical model, called TTDERM, allows us to account for variable exposure times and time between exposures, temporal and spatial variations in skin and compound properties, and uncertainty in model parameters. Using TTDERM we investigate the use of a macro-activity parameter (cumulative contact time) for predicting daily (24 hour) integrated uptake of pesticides during complex exposure scenarios. For characteristic child behaviors and hand loading and unloading rates, we find that a power law represents the relationship between cumulative contact time and cumulative mass transport through the skin. With almost no loss of reliability, this simple relationship can be used in place of the more complex micro-activity simulations that require activity data on one- to five-minute intervals. The methods developed in this study can be used to guide dermal exposure model refinements and exposure measurement study design.
The United States Environmental Protection Agency though its Office of Research and Development partially funded the research described here under IAG DW-988-38190-01-0 to Lawrence Berkeley National Laboratory through the US Department of Energy under Contract Grant DE-AC03-76SF00098.
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| JOURNAL |
A Pilot Study of the Influence of Residential Hac Duty Cycle on Indoor Air Quality (Ae) |
04/01/2004
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THORNBURG, J., C. E. RODES, P. LAWLESS, C. D. STEVENS, AND R. W. WILLIAMS. A Pilot Study of the Influence of Residential Hac Duty Cycle on Indoor Air Quality (Ae). ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 38(11):1567-1577, (2004).
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A simple methodology was developed to collect measurements of duty cycle, the fraction of time the heating and air conditioning (HAC) system was operating, inside residences. The primary purpose of the measurements was to assess whether the HAC duty cycle was related to reductions in indoor particulate matter (PM) concentrations. A miniature temperature logger placed on an HAC outlet vent monitored changes in temperature as the system cooled or heated the residence. Temperature step changes signaling duty cycle periods were identified using spreadsheet macros. Parallel measurements of 24-hour integrated air exchange rates (AERs) and indoor PM2.5 and PM10 concentrations were collected to determine relationships with the duty cycle. The mild temperatures (mean = 18.7 °C) present during the Spring season of the RTP PM Panel Study and personal comfort preferences caused low and variable daily duty cycles (mean = 0.061, std. dev. = 0.054) in both heating and cooling mode. Warmer ambient temperatures during the Fall season of the Tampa Asthmatics Children Study (TACS) resulted in cooling-only HAC operation, with a higher mean duty cycle of 0.21 (std. dev. = 0.11). Statistically significant linear relationships were observed between daily average duty cycle and the ambient temperature for both studies. Duty cycle exhibited a strong diurnal pattern commensurate with ambient temperature fluctuations. Duty cycles were positively associated with the residence AERs for heating-mode operations, but negatively associated when operating in cooling mode. Personal preferences contributed to the variability in the relationship between duty cycle and air exchange rate. The relationship between duty cycle and PM2.5 or PM10 indoor-outdoor ratios were not statistically significant. The association of duty cycle with indoor-outdoor ratio was confounded by the short time span (mean of 10.3 minutes for the TACS) of HAC system operation and the presence of strong indoor sources altering the indoor concentration levels.
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| JOURNAL |
Source Strengths of Ultrafine and Fine Particles Due to Cooking With a Gas Stove |
04/15/2004
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Wallace, L. A., C. HowardReed, AND S. J. Emmerich. Source Strengths of Ultrafine and Fine Particles Due to Cooking With a Gas Stove. ENVIRONMENTAL SCIENCE & TECHNOLOGY 38(8):2304-2311, (2004).
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Cooking, particularly frying, is an important source of particles indoors. Few studies have measured a full range of particle sizes, including ultrafine particles, produced during cooking. In this study, semicontinuous instruments with fine size discriminating ability were used to calculate particle counts in 124 size bins from 0.01 um to 2.5 um. Data were collected at 5-minute intervals for 18 months in an occupied house. Tracer gas measurements were made every 10 min in each of 10 rooms of the house to establish air change rates. Cooking episodes (N = 44) were selected meeting certain criteria (high concentrations, no concurrent indoor sources, long smooth decay curves) and the number and volume of particles produced was determined for each size category. For each episode, the particle decay rate was determined and used to determine the source strength for each size category. The selected cooking episodes (mostly frying) were capable of producing about 1014 particles over the length of the cooking period (about 15 minutes), more than 90 % of them in the ultrafine (< 0.1 um) range, with an estimated whole-house volume concentration of 50 (um/cm)3. More than 60 % of this volume occurred in the 0.1um to 0.3 um range. Frying produced peak numbers of particles at about 0.06 um, with a secondary peak at 0.01 um. The peak volume occurred at a diameter of about 0.16 um. Since the cooking episodes selected were biased toward higher concentrations, the particle concentrations measured during about 600 hours of morning and evening cooking over a full year were compared to concentrations measured during non-cooking periods at the same times. Cooking was capable of producing more than 10 times the ultrafine particle number observed during non-cooking periods. Levels of PM2.5 were increased during cooking by a factor of 3. Breakfast cooking (mainly heating water for coffee and using an electric toaster) produced concentrations about half those produced from more complex dinnertime cooking. Although the number and volume concentrations observed depend on air change rates, house volume, and deposition rates due to fans and filters, the source strengths calculated here are independent of these variables and may be used to estimate number and volume concentrations in other types of homes with widely varying volumes, ventilation rates and heating and air conditioning practices.
This study was partially funded by an EPA Internal Grant to the corresponding author. It was also supported by the National Institute of Standards and Technology. The paper has been reviewed by both agencies and cleared for publication. Certain commercial equipment, instruments, or materials are identified in this paper in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose.
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| JOURNAL |
Determination of Secondary Organic Aerosol Products from the Photooxidation of Toluene and Their Implications in Ambient PM2.5 |
01/01/2004
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Kleindienst, T. E., T. S. Conver, C. D. McIver, AND E. O. Edney. Determination of Secondary Organic Aerosol Products from the Photooxidation of Toluene and Their Implications in Ambient PM2.5. JOURNAL OF ATMOSPHERIC CHEMISTRY 47(1):79-100, (2004).
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Laboratory study was carried out to investigate the secondary organic aerosol products from photooxidation of the aromatic hydrocarbon toluene. The laboratory experiments consisted of irradiating toluene/propylene/NOX/air mixtures in a smog chamber operated in the dynamic mode and collecting submicron secondary organic aerosol samples through a sampling train that consisted of an XAD denuder and a ZefluorTM filter. Oxidation products in the filter extracts were treated using O-(2,3,4,5,6,-pentafluorobenzyl)-hydroxylamine (PFBHA) to derivatize carbonyl groups followed by treatment with N,O-Bis(trimethylsilyl)-acetamide (BSTFA) to derivatize OH groups. The derivatized products were detected with a positive chemical ionization (CI) gas chromatography ion trap mass spectroscopy (GC-ITMS) system. The results of the GC-ITMS analyses were consistent with the previous studies that demonstrated the formation of multi-functional oxygenates. Denuder results showed that many of these same compounds were present in the gas, as well as, the particle phase. Moreover, evidence was found for a series of multifunctional acids produced as higher order oxidation products of the toluene/NOX system. Products having nearly the same mass spectrum were also found in the ambient environment using identical analytical techniques. These products having multiple acid and alcoholic-OH moieties have substantially lower volatility than previously reported SOA products of the toluene photooxidation and might serve as an indicator for aromatic oxidation in the ambient atmosphere.
The U.S. Environmental Protection Agency through its Office of Research and Development funded and collaborated in the research described here under Contract 68-D-00-206 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
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| JOURNAL |
Receptor Model Comparisons and Wind Direction Analyses of Volatile Organic Compounds and Submicrometer Particles in An Arid, Binational, Urban Airshed |
04/15/2004
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Mukerjee, S., G. A. Norris, L. Smith, C. A. Noble, L. M. Neas, A. H. Ozkaynak, AND M. Gonzales. Receptor Model Comparisons and Wind Direction Analyses of Volatile Organic Compounds and Submicrometer Particles in An Arid, Binational, Urban Airshed. ENVIRONMENTAL SCIENCE AND TECHNOLOGY 38(8):2317-2327, (2004).
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The relationship between continuous measurements of volatile organic compounds sources and particle number was evaluated at a Photochemical Assessment Monitoring Station Network (PAMS) site located near the U.S.-Mexico Border in central El Paso, TX. Sources of volatile organic compounds (VOCs) were investigated using the multivariate receptor model UNMIX and the effective variance least squares receptor model known as Chemical Mass Balance (CMB, Version 8.0). As expected from PAMS measurements, overall findings from data screening as well as both receptor models confirmed that mobile sources were the major source of VOCs. Comparison of hourly source contribution estimates (SCEs) from the two receptor models revealed significant differences in motor vehicle exhaust and evaporative gasoline contributions. However, the motor vehicle exhaust contributions were highly correlated with each other. Motor vehicle exhaust was also correlated with the ultrafine and accumulation mode particle count, which suggests that motor vehicle exhaust is a source of these particles at the measurement site. Wind sector analyses were performed using the SCE and pollutant data to assess source location of VOCs, particle count, and criteria pollutants. Results from this study have application to source apportionment studies and mobile source emission control strategies that are ongoing in this air shed.
The US Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under contract 68-D-99-012 to Research Triangle Institute and contract 68-D0-0206 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
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| JOURNAL |
Fugacity-Based Indoor Residential Pesticide Fate Model |
02/28/2004
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Bennett, D. H. AND E. J. Furtaw Jr. Fugacity-Based Indoor Residential Pesticide Fate Model. ENVIRONMENTAL SCIENCE AND TECHNOLOGY 38(7):2142-2152, (2004).
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Dermal and non-dietary pathways are possibly important for exposure to pesticides used in residences. Limited data have been collected on pesticide concentrations in residential air and surfaces following application. Models may be useful for interpreting these data and to make predictions about concentrations in the home for other pesticides based on chemical properties. We present a dynamic mass-balance compartment model based on fugacity principles. The model includes air (both gas phase and aerosols), carpet, smooth flooring, and walls as model compartments. Six size fractions of particulate matter with different fate and transport properties are included. We determine the compartmental fugacity capacity and mass-transfer rate coefficients between compartments. We compare model results to chlorpyrifos air and carpet measurements from an independent study. For a comparison, we run the same simulation for diazinon and permethrin. We quantify the effect of parameter uncertainty and model uncertainties related to the source release rate and conduct a sensitivity analysis to determine which parameters contribute most to output uncertainty. In the model comparison to chlorpyrifos measurements, the model results are of the same order of magnitude as measured values, but tend to overpredict the measured data, thus indicating the need for a better understanding of emissions from treated surfaces.
The United States Environmental Protection Agency through its Office of Research and Development partially funded and collaborated in the research descrived here under assistance agreement number DW-988-38190-01-0 to Lawrence Berkeley National Laboratory. It has been subjected to Agency review and approved for publication.
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| JOURNAL |
Development of Evaluation of a Quantitative Video-Fluorescence Imaging System and Fluorescent Tracer for Measuring Transfer of Pesticide Residues from Surfaces to Hands With Repeated Contacts |
08/06/2004
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Ivancic, W., M. G. Nishioka, R. Barnes, E. A. CohenHubal, M. Morara, AND S. Bortnick. Development of Evaluation of a Quantitative Video-Fluorescence Imaging System and Fluorescent Tracer for Measuring Transfer of Pesticide Residues from Surfaces to Hands With Repeated Contacts. ANNALS OF OCCUPATIONAL HYGIENE 48(6):519-531, (2004).
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A video imaging system and the associated quantification methods have been developed for measurement of the transfers of a fluorescent tracer from surfaces to hands. The highly fluorescent compound riboflavin (Vitamin B2), which is also water soluble and non-toxic, was chosen as the tracer compound to simulate the transfers from surfaces to hands of pesticide residues deposited on carpeted and laminate surfaces of a residence. The system was designed around the unique properties of riboflavin. Excitation energy was centered near 440 nm (in the blue region of the visible spectrum); emitted energy was measured at 600 nm (in the red/orange region), well beyond the significant fluorescence peak maximum of natural skin. A video camera system with an image intensifier was interfaced to an image processing analysis software system. Quantification utilized chemometric techniques to account for the non-linearity of pixel detectivity and non-linear excitation strength. Method quantification and detection limits were approximately 0.1 ug/cm2 and 0.02 ug/cm2, respectively. The relative error was ~100% at the quantification limit, but <20% at higher levels. Transfers of riboflavin to hands, resulting in dermal loadings in the range of 0.1 - 2.0 ug/cm2, were measured with this system from surfaces whose loadings approximated the pesticide levels that occur in homes after broadcast application.
This work has been funded by the US EPA under contract No. 68-D-99-011 to Battelle. It has been subjected to agency review and approved for publication
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| JOURNAL |
Preface: Special Issue of Atmospheric Environment on Findings from EPA's Particulate Matter Supersites Program |
06/01/2004
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Solomon, P. A. Preface: Special Issue of Atmospheric Environment on Findings from EPA's Particulate Matter Supersites Program. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 38(20):3101-3106, (2004).
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The Supersites Program is a methods development and evaluation, measurements, modeling, and data analysis program designed to provide key stakeholders in the science, regulatory, and policy communities with information to support primarily implementation of National Ambient Air Quality Standards. The program also supports health communities by providing essential information on the components of PM and PM precursors and the fate and accumulation of PM in air. The papers presented in this special peer-reviewed journal issue represent a small sub-set of papers being published by the Supersites Projects and represents one of 4 special journal issues published to date. The preface provides a synthesis of the papers within by summarizing key atmospheric sciences findings based on the results presented within and then from those key findings identifying key policy relevant and health relevant findings. The preface represents a first step in an overall synthesis of results from the Supersites Program and Related Studies.
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| JOURNAL |
Comparisons of the Dust/Smoke Particulate That Settled Inside and the Surrounding Buildings and Outside on the Streets of Southern New York City After the Collapse of the World Trade Center, 11 September 2001 |
05/04/2004
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Yiin, L. M., J. R. Millette, A. F. Vette, V. Ilacqua, C. Quan, J. Gorczynski, M. Kendall, L. C. Chen, C. P. Weisel, B. Buckley, I. Yang, AND P. J. Lioy. Comparisons of the Dust/Smoke Particulate That Settled Inside and the Surrounding Buildings and Outside on the Streets of Southern New York City After the Collapse of the World Trade Center, 11 September 2001. JOURNAL OF AIR & WASTE MANAGEMENT ASSOCIATION 54(5):515-528, (2004).
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The collapse of the World Trade Center (WTC) on September 11, 2001 generated large amounts of dust and smoke that settled in the surrounding indoor and outdoor environments in southern Manhattan. Sixteen dust samples were collected from undisturbed locations inside two uncleaned buildings that we were given access to and were adjacent to Ground Zero. These samples were analyzed for morphology, metals, and organic compounds, and the results were compared with the previously reported outdoor WTC dust/smoke results. We also analyzed seven additional dust samples provided by residents in the local neighborhoods. The morphologic analyses showed that the indoor WTC dust/smoke samples were similar to the outdoor WTC dust/smoke samples in composition and characteristics, but with more than 50% mass in the < 53 um size fraction. This was in contrast to the outdoor samples that contained >50% of mass above > 53 um. Elemental analyses also showed the similarities, but at lower concentrations. Organic compounds present in the outdoor samples, were also detected in the indoor samples. Conversely, the resident-provided convenience dust samples were different from either the WTC indoor or outdoor samples in composition and pH, indicating that they were not WTC affected locations. In summary, the indoor dust/smoke was similar in concentration to the outdoor dust/smoke, but had a greater percentage of mass < 53 um in diameter.
The U.S. Environmental Protection Agency through its Office of Research and Development partially funded and collaborated in the research described here. It has been subjected to Agency review and approved for publication.
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| JOURNAL |
Comments on "SIZE Distribution of Organonitrates in Ambient Aerosol Collected in Houston, Texas," Aerosol Science and Technology, 36:983-992 (2002) |
08/01/2004
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Weathers, W. Comments on "SIZE Distribution of Organonitrates in Ambient Aerosol Collected in Houston, Texas," Aerosol Science and Technology, 36:983-992 (2002). AEROSOL SCIENCE TECHNOLOGY. American Association for Aerosol Research, 38(8):782-786, (2004).
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A previous article in this journal reported the results of an FTIR analysis of the ambient aerosol collected during a file study in Houston, Texas during August and September of 2000. The emphasis of that article was on the organonitrates collected during the study. In the discussion of their research, the authors noted some discrepancies between the organonitrate absorbances observed in Houston compared to those seen in a previous study conducted in Los Angeles, California. They offer several explanations for the observed differences. In these comments, an alternative explanation is offered for these differences.
The United States Environmental Protection Agency through its Office of Research and Development funded an managed the research described here. It has been subjected to the Agency's administrative review and approved for publication as an EPA document.
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| JOURNAL |
Chlordanes in the Indoor and Outdoor Air of Three U.S. Cities |
04/13/2004
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Offenberg, J., Y. Y. Naumova, B. Turpin, S. Eisenreich, M. T. Morandi, T. Stock, S. D. Colomes, A. M. Winer, D. M. Spektor, J. Zhang, AND C. P. Weisel. Chlordanes in the Indoor and Outdoor Air of Three U.S. Cities. ENVIRONMENTAL SCIENCE AND TECHNOLOGY 38(10):2760-2768, (2004).
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Indoor and outdoor concentrations of six Chlordane components (trans-chlordane, cis-chlordane, trans- nonachlor, cis-nonachlor, oxychlordane and MC5) were measured at 157 residences, all of which were inhabited by non-smoking individuals, in three urban areas during June 1999-May 2000. The analyses were conducted on a subset of 48 hour integrated samples collected in Los Angeles County, CA, Houston, TX, and Elizabeth, NJ within the Relationship of Indoor, Outdoor, and Personal Air (RIOPA) study. Both particle bound (PM2.5; quartz fiber filter) and vapor phase (PUF sorbant) chlordane concentrations were separately measured by GC / EI MS after solvent extraction. The outdoor (gas + particle) total Chlordane (trans-chlordane + cis-chlordane + trans-nonachlor + cis-nonachlor) concentrations ranged from 0.036 to 4.27 ng m-3 in Los Angeles County, from 0.008 to 11.00 ng m-3 in Elizabeth, and from 0.062 to 1.77 ng m-3 in Houston. The corresponding indoor total chlordane concentrations ranged from 0.037 to 112.0 ng m-3 in Los Angeles County, from 0.260 to 31.80 ng m-3 in Elizabeth, and from 0.410 to 38.90 ng m-3 in Houston study homes. Geometric mean concentrations were higher in indoor air than outdoor air (1.98 vs. 0.58 ng m-3 in CA; 1.30 vs. 0.17 ng m-3 in NJ; 4.18 vs. 0.28 ng m-3 in TX), which suggests there are significant indoor sources of Chlordane species in a subset of homes in each of the three cities. Calculated source strengths relate to home age, with the highest apparent indoor source strengths occurring in unattached single-family homes built during the period from 1945 to 1959. Principle indoor sources of chlordanes likely include volatilization from residues of indoor application of chlordanes and infiltration from sub-surface and foundation application of chlordane-containing termiticides during home construction.
The United States Environmental Protection Agency partially funded the research described here. This work has been subjected to Agency review and has been cleared for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
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| JOURNAL |
Preface: Special Issue of Atmospheric Environment, for Particulate Matter: Atmospheric Sciences, Exposure and the Fourth Colloquium on PM and Human Health |
10/01/2004
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Middlebrook, A. M., J. Turner, AND P. A. Solomon. Preface: Special Issue of Atmospheric Environment, for Particulate Matter: Atmospheric Sciences, Exposure and the Fourth Colloquium on PM and Human Health. ATMOSPHERIC ENVIRONMENT. Elsevier Online, New York, NY, 38(31):5179-5181, (2004).
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In a continuing effort to improve communications among the atmospheric sciences, policy, and health communities, an international specialty conference was initiated in 2001 that took place in April 2003 in Pittsburgh, PA. The conference entitled, "Particulate Matter: Atmospheric Sciences, Exposure, and the Fourth Colloquium on PM and Human Health," provided a major show case for presentations and a meaningful exchange of information among the three communities. Over 350 papers were presented as posters along with a series of workshops on first day followed by 2.5 days of plenary sessions addressing key atmospheric sciences and health questions related to PM, its fate and accumulation in air, linkages between source and receptor, and PM and health relationships. This special issue of Atmospheric Environment, for which this preface describes, is one of six resulting from the subjected meeting. Three others are presented in different atmospheric sciences journals (AS&T, JGR-Atmospheres, and JAWMA) and in two special issues of Inhalation Toxicology. This preface simply introduces the conference and the special issue.
The United states Environmental Protection Agency through its Office of Research and Development funded and managed the preparation of this preface. It has been subjected to Agency's administrative review and approved for publication.
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| JOURNAL |
Comparison of Immunoassay and Gas Chromatography/Mass Spectrometry Methods for Measuring 3,5,6-Trichloro-2pyridinol in Multiple Sample Media |
07/26/2004
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Chuang, J. C., J. M. Van Emon, A. W. Reed, AND N. Junod. Comparison of Immunoassay and Gas Chromatography/Mass Spectrometry Methods for Measuring 3,5,6-Trichloro-2pyridinol in Multiple Sample Media. ANALYTICA CHIMICA ACTA 517(1-2):177-185, (2004).
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Two enzyme-linked immunosorbent assay (ELISA) methods were evaluated for the determination of 3,5,6-trichloro-2-pyridinol (3,5,6-TCP) in multiple sample media (dust, soil, food, and urine). The dust and soil samples were analyzed by a commercial RaPID immunoassay testing kit. The food and urine samples were analyzed by a laboratory-based 96-microwell plate immunoassay format. Methanol was used as the extraction solvent for the preparation of the dust and soil samples for analysis by both the ELISA and gas chromatography/mass spectrometry (GC/MS) procedures. Chlorobutane was used for extraction of the urine samples for each method. The food samples were extracted with methanol for GC/MS and with acidic methanol for ELISA. The percent difference of the duplicate RaPID assays ranged from 0 to 43.4% for dust and from 0 to 47.9% for soil. The percent relative standard deviation of the 96-microwell plate triplicate assays was 15% or less for food and urine samples. Quantitative recoveries of 3,5,6-TCP were obtained for the spiked dust, soil, food and urine samples by ELISA ranging from 71 to 102%. Quantitative recoveries (>90%) of 3,5,6-TCP were also obtained for these samples by the GC/MS procedure. The overall method precision of these samples was within + 10% using the GC/MS procedure. The immunoassay and GC/MS data were highly correlated, with correlation coefficients of 0.98 for dust, 0.98 for soil, 0.93 for food and 0.98 for urine. Both ELISA methods can be used as quantitative monitoring tools for 3,5,6-TCP concentrations in dust, soil, food, and urine samples.
This work was funded wholly or in part by the U.S. Environmental Protection Agency through Contract 68-D-99-011. This paper has been reviewed in accordance with the US Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names and commercial products does not constitute endorsement or recommendation for use.
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| JOURNAL |
Estimated Hourly Personal Exposures to Ambient and Non-Ambient Particulate Matter Among Sensitive Populations in Seattle, Washington |
09/01/2004
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Allen, R., L. A. Wallace, T. Larson, L. Sheppard, AND L. S. Liu. Estimated Hourly Personal Exposures to Ambient and Non-Ambient Particulate Matter Among Sensitive Populations in Seattle, Washington. JOURNAL OF AIR & WASTE MANAGEMENT ASSOCIATION 54(9):1197-1211, (2004).
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Epidemiological studies of particulate matter (PM) routinely use concentrations measured with stationary outdoor monitors as surrogates for personal exposure. Despite the frequently reported poor correlations between ambient concentrations and total personal exposure, the epidemiologic associations between ambient concentrations and health effects depend on the correlation between ambient concentrations and personal exposure to ambient-generated PM. This paper separates personal PM exposure into ambient and non-ambient components and estimates the outdoor contribution to personal PM exposures using continuous light scattering data collected from 38 subjects in Seattle, WA. Across all subjects, the average exposure encountered indoors at home was lower than in all other microenvironments. Cooking and being at school were associated with elevated levels of exposure. Previously published estimates of particle infiltration (Finf) were combined with time-location data to estimate an ambient contribution fraction ( 'a', mean = 0.66 +/- 0.21) for each subject. The mean 'a' was significantly lower for subjects monitored during the heating season (0.55 +/- 0.16) than during the non-heating season (0.80 +/- 0.17). Our modeled 'a' estimates agreed well with those estimated using the sulfur-tracer method (slope = 1.08; R2 = 0.67). We modeled exposure to ambient and non-ambient PM using both continuous light scattering and 24-hr gravimetric data and found good agreement between the two methods. On average, ambient particles accounted for 48% of the total personal exposure (range: 21-80%). The personal activity exposure was highly influenced by time spent away from monitored microenvironments. The median hourly longitudinal correlation between central-site concentrations and personal exposures was 0.30. Although both 'a' and the non-ambient sources influence the personal-central relationship, the latter seems to dominate. Thus, total personal exposure may be poorly predicted by stationary outdoor monitors, particularly among persons whose PM exposure is dominated by non-ambient exposures, e.g. those living in tightly sealed homes, those who cook, and children.
This work was funded by a cooperative agreement between the University of Washington and the U.S. EPA (#CR82717701)and by the Northwest Research Center for Particulate Air Pollution and Health (U.S. EPA grant #CR827355). It has been subjected to Agency review and approved for publication
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Source Apportionment of Indoor, Outdoor, and Personal PM2.5 in Seattle, Washington, Using Positive Matrix Factorization |
09/01/2004
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Larson, T., T. Gould, C. Simpson, L. Liu, C. S. Claiborn, AND J. JUNGERS. Source Apportionment of Indoor, Outdoor, and Personal PM2.5 in Seattle, Washington, Using Positive Matrix Factorization. JOURNAL OF AIR & WASTE MANAGEMENT ASSOCIATION 54(9):1175-1187, (2004).
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As part of a large exposure assessment and health effects panel study, 33 trace elements and light-absorbing carbon were measured on 24-hr particulate matter with an aero-dynamic diameter <2.5 um (PM2.5) fixed-site filter samples collected between September 26, 2000, and May 25, 2001, at a central outdoor site, immediately outside each subject's residence, inside each residence, and on each subject (personal sample). Both two-way (PMF2) and three-way (PMF3) positive matrix factorization were used to deduce the sources contributing to PM2.5. Five sources contributing to the indoor and outdoor samples were identified: vegetative burning, mobile emissions, secondary sulfate, a source rich in chlorine, and a source of crustal-derived material. Vegetative burning contributed mor PM2.5 mass on average than any other source in all microenvironments, with average values estimated by PMF2 and PMF3, respectively, of 7.6 and 8.7 ug/m3 for the outdoor samples, 4 and 5.3 ug/m3 for the indoor samples, and 3.8 and 3.4 ug/m3 for the personal samples. Personal exposure to the combustion-related particles were correlated with outdoor sources, whereas exposure to the crustal and chlorine-rich particles was not. Personal exposures to crustal sources were strongly associated with personal activities, especially time spent at school among the child subjects.
This paper has been reviewed in accordance with the US EPA's peer and administrative review policies and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| JOURNAL |
Chlordanes in the Mid-Atlantic Atmosphere: New Jersey 1997-1999 |
08/01/2004
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Offenberg, J., E. D. Nelson, C. L. Gigliotti, AND S. Eisenreich. Chlordanes in the Mid-Atlantic Atmosphere: New Jersey 1997-1999. ENVIRONMENTAL SCIENCE AND TECHNOLOGY 38(13):3488-3497, (2004).
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To characterize the atmospheric dynamics and behavior of chlordane compounds in the mid-Atlantic region of the United States, atmospheric concentrations were measured in 1997-1999 at three New Jersey locations as part of the New Jersey Atmospheric Deposition Network (NJADN) project. Observed concentrations of Sigma-chlordanes (cis-chlordane + trans-chlordane + cis-nonachlor + transnonachlor) are log-normally distributed, with a geometric mean concentration of 77.1 pg m-3 and range from 6.1 to 481 pg m-3. Gas-phase species comprised 83% (+/-23%) of the Sigma-chlordanes species across all samples at all location. Gas-phase Sigma-chlordane concentrations are inversely proportional to temperature, with higher concentrations during periods of warmer air temperatures. Observed concentrations do not correlate with wind direction or air mass history, which suggests that observed concentrations in the New Jersey atmosphere are due to volatilization from soils and surfaces on the regional scale.
The United States Environmental Protection Agency through its Office of Research and Development collaborated in the research described here. It is now being subjected to peer-review and has not been cleared for publication.
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Immunochemical Determination of Dioxins in Sediment and Serum Samples |
08/01/2004
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Nichkova, M., E. Park, M. E. Koivunen, Kamita, S,G., S. J. Gee, J. C. Chuang, J. M. Van Emon, AND B. D. Hammock. Immunochemical Determination of Dioxins in Sediment and Serum Samples. TALANTA 63(5):1213-1223, (2004).
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Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are considered highly toxic contaminants and the environmental and biological monitoring of these compounds is of great concern. Immunoassays may be used as screening methods to satisfy the growing demand for rapid and low cost analysis. In this work we describe the application of an immunoassay that uses 2,3,7-trichloro-8-methyldibenzo-p-dioxin (TMDD) as a surrogate standard for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to sediment and human serum samples. Sample extraction and preparation methods were developed with the aim to establish the simplest, cost-effective and efficient removal of the matrix interferences in the Enzyme-Linked Immunosorbent Assay (ELISA). The overall method for sediments is based on a hexane extraction; clean up by a multilayered silica gel column and an activated carbon column; an organic solvent exchange with DMSO-Triton X-100 and ELISA measurement. The gas chromatography - high resolution mass spectrometry (GC-HRMS) validation studies (n=13) revealed that the method is suitable for the TEQ (toxic equivalents) screening of dioxin in sediments with a method detection limit of about 100 pg g-1 dry sediment with a precision of 13-33%RSD. The analysis of a large number of samples originating from different sources would be required to establish more precisely the screening level, as well as the number of false positives and negatives of dioxin TEQ by the immunoassay for sediments. The immunoassay method for sediment analysis offers improvement in speed, sample throughput, and cost in comparison to GC-HRMS. Dioxins were determined in serum samples after a simple liquid-liquid extraction and solvent exchange into DMSO-Triton X-100 without further dilution. The current method (approximate method LOQ of 200 pg ml-1serum) is not sufficiently sensitive for the determination of dioxins in serum to measure acceptable exposure limit.
The U.S. Environmental Protection Agency through its Office of Research and Development (ORD) partially funded and collaborated in the research described here under contract No. GS-10F-00275K to Battelle. It has been subjected to the Agency's review and approved for publication. Mention of trade names and commercial products does not constitute endorsement or recommendation for use. This research is also funded by grants from the National Institute of Environmental Health Sciences 5 P42 ES04699 and NIEHS Center for Environmental Health Sciences P30 ES05707.
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Chemical Characterization of Ambient Particulate Matter Near the World Trade Center: Elemental Carbon, Organic Carbon, and Mass Reconstruction |
09/01/2004
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Olson, D. A., G. A. Norris, M. S. Landis, AND A. F. Vette. Chemical Characterization of Ambient Particulate Matter Near the World Trade Center: Elemental Carbon, Organic Carbon, and Mass Reconstruction. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 38(17):4465-4473, (2004).
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Concentrations of elemental carbon (EC), organic carbon matter (OM), particulate matter less than 2.5 um (PM2.5), and reconstructed soil, trace element oxides, and sulfate are reported from four locations near the World Trade Center (WTC) complex for airborne particulate matter (PM) samples collected from September 2001 through January 2002. Across the four sampling sites, daily mean concentrations ranged from 1.5-6.8 ug/m3 for EC, from 10.2-31.4 ug/m3 for OM, and from 22.6-66.2 ug/m3 for PM2.5. Highest concentrations of PM species were generally measured north and west of the WTC complex. Total carbon matter and sulfate constituted the largest fraction of reconstructed PM2.5 concentrations. Concentrations of PM species across all sites decreased from the period when fires were present at the WTC complex (before December 19, 2001) to the period after fires. Averaged over all sites, concentrations decreased by 25.6 ug/m3 for PM2.5, 2.7 ug/m3 for EC, and 9.2 ug/m3 for OM from the fire period to after fire period.
The United States Environmental Protection Agency through its Office of Research and Development funded and managed the research described here. It has been subjected to Agency's administration review and approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| JOURNAL |
Preface to Special Section on Particulate Matter: Atmospheric Sciences, Exposure, and the Fourth Colloquium on Particulate Matter and Human Health |
08/11/2004
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Brock, C. A., D. J. Eatough, AND P. A. Solomon. Preface to Special Section on Particulate Matter: Atmospheric Sciences, Exposure, and the Fourth Colloquium on Particulate Matter and Human Health. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 109(D16):1-3, (2004).
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In response to epidemiological studies published over twenty years ago, at least three research communities have been intensively studying airborne particulate matter (PM). These efforts have been coordinated by approaching the source - atmospheric accumulation/receptor - exposure - dose - health effects paradigm (adopted from NRC, 2001) from different perspectives or along different parts of the paradigm. The atmospheric sciences communities consider the emissions of particles and precursors from sources, their transport and transformation in air to receptor locations, and finally removal from the atmosphere. The exposure communities' interest is to examine the pathways by which pollution or particulate matter, in this case, approaches and enters the body, typically by trying to relate PM concentrations at a central location(s) to exposure and perhaps dose. Both the atmospheric sciences and exposure communities approach the paradigm from left to right. In contrast, the health effects communities have studied health outcomes, including hospital admissions, school absences, disease rates and deaths in human populations, and potential mechanisms of biological actions in laboratory settings. In general, the health effects communities' approach the paradigm from right to left attempting to correlate an observed adverse health effect with dose or exposure measures. For the most part, research results are reported in scientific publications and conferences for each community respectively. Over the years, there has been little effort to integrate information from these diverse groups in a substantive way. While a major attempt took place in 1998 at the Chapel Hill workshop (Albritton and Greenbaum, 1998), little has occurred since.
The United States Environmental Protection Agency through its Office of Research and Development funded and managed the preparation of this preface. It has been subjected to Agency's administrative review and approved for publication as an EPA document.
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| JOURNAL |
Understanding Variability in Time Spent in Selected Locations for 7-12 Year Old Children |
05/01/2004
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Xue, J., T. R. McCurdy, J. D. Spengler, AND A. H. Ozkaynak. Understanding Variability in Time Spent in Selected Locations for 7-12 Year Old Children. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY 14(3):222-233, (2004).
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This paper summarizes a series of analyses of clustered, sequential activity/location data collected by Harvard University for 160 children aged 7-12 in Southern California (Geyh et al., 2000). The main purpose of the paper is to understand intra- and inter-variability in the time spent by the sample in the outdoor location, the location exhibiting the most variability of the ones evaluated. The data were analyzed using distribution-free hypothesis-testing (K-S tests of the distributions), generalized linear modeling techniques, and random-sampling schemes that produced "cohorts" whose descriptive statistical characteristics were evaluated against the original dataset. Most importantly, our analyses indicate that subdividing the population into appropriate cohorts better replicates parameters of the original data, including the interclass correlation coefficient (ICC), which is a relative measure of the intra- and inter-individual variability inherent in the original data. While the findings of our analyses are consistent with previous assessments of "time budget" and physical activity data, they are constrained by the rather homogeneous sample available to us. Due to a general lack of longitudinal human activity/location data available for other age/gender cohorts, we are unable to generalize our findings to other population subgroups.
The analyses reported here were undertaken by staff scientists of the US Environmental Protection Agency and the Harvard School of Public Health. Its content is soley the responsibility of the authors and does not necessarily represent the official views of either organization or the funding sources mentioned below. It has been subjected to Agency and outside peer review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
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| JOURNAL |
Identification and Quantification of Aerosol Polar Oxygenated Compounds Bearing Carboxylic and/or Hydroxyl Groups. 1. Method Development |
08/15/2004
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Jaoui, M., T. E. Kleindienst, M. Lewandowski, AND E. O. Edney. Identification and Quantification of Aerosol Polar Oxygenated Compounds Bearing Carboxylic and/or Hydroxyl Groups. 1. Method Development. ANALYTICAL CHEMISTRY 76(16):4765-4778, (2004).
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In this study, a new analytical technique was developed for the identification and quantification of multi-functional compounds containing simultaneously at least one hydroxyl or one carboxylic group, or both. This technique is based on derivatizing first the carboxylic group(s) of the multi-functional compound using an alcohol (e.g., methanol, 1-butanol) in the presence of a relatively strong Lewis acid (BF3) as a catalyst. This esterification reaction quickly and quantitatively converts carboxylic acids to their ester forms. The second step is based on silylation of the ester compounds using bis(trimethylsilyl) trifluoroacetamide (BSTFA) as the derivatizing agent. For compounds bearing ketone groups in addition to carboxylic and hydroxyl groups, a third step was used based on PFBHA derivatization of the carbonyls. Different parameters including temperature, reaction time, and effect due to artifacts were optimized. A GC/MS in EI and in methane-CI mode was used for the analysis of these compounds.
The new approach was tested on a number of multifunctional compounds. The interpretation of their EI (70 eV) and CI mass spectra shows that critical information is gained leading to unambiguous identification of unknown compounds. For example, when derivatized only with BF3-methanol, their mass spectra comprise primary ions at m/z M + 1, M + 29, and M+. - 31 for compounds bearing only carboxylic groups and M+. + 1, M+. + 29, M - 31, and M - 17 for those bearing hydroxyl and carboxylic groups. However, when a second derivatization (BSTFA) was used, compounds bearing hydroxyl and carboxylic groups simultaneously show, in addition to the ions observed before, ions at m/z M+. + 73, M+. - 15, M+. - 59, M+. - 75, M+. - 89, and 73. To the best of our knowledge, this technique describes systematically for the first time a method for identifying multi-functional oxygenated compounds containing simultaneously one or more hydroxyl and carboxylic acid groups.
The U.S. Environmental Protection Agency through its Office of Research and Development funded and collaborated in the research described here under Contract 68-D-00-206 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
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Characterizing Residue Transfer Efficiencies Using a Fluorescent Imaging Technique |
08/11/2004
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CohenHubal, E. A., J. C. Suggs, M. G. Nishioka, AND W. Ivancic. Characterizing Residue Transfer Efficiencies Using a Fluorescent Imaging Technique. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY. Nature Publishing Group, London, Uk, 1-10, (2004).
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To reduce the uncertainty associated with current estimates of children's exposure to pesticides by dermal contact and indirect ingestion, residue transfer data are required. Prior to conducting exhaustive studies, a screening study to identify the important parameters for characterizing these transfers was designed. A fluorescence imaging system was developed (Ivancic et.al., in press) to facilitate collection of surface residue transfer data for repeated contacts. Next, parameters that affect residue transfer from surface-to-skin, skin-to-other objects, and skin-to-mouth were evaluated using the imaging system and the fluorescent tracer riboflavin as a surrogate for pesticide residues. Riboflavin was applied as a residue to surfaces of interest. Controlled transfer experiments were conducted by varying contact parameters with each trial. The mass of a tracer transferred was measured and the contact surface area estimated using video imaging techniques. Parameters evaluated included: surface type, surface loading, contact motion, pressure, duration, and skin condition. Transfers both onto, and off of, the hand were measured. To efficiently identify parameter changes resulting in significant effects, the Youden ruggedness test was used to select the combination of parameters varied in each contact trial. In this way, more than one parameter could be varied at a time and the number of trials required was minimized. Results of this study showed that surface loading and skin condition (significant at alpha =.05) are among the important parameters for characterizing residue transfers of riboflavin. Duration of contact within the time range investigated does not have a significant effect on transfer of this tracer. Results of this study demonstrate the potential for collecting dermal transfer data using the Ivancic et. al. fluorescence imaging system and provide preliminary data to reduce uncertainty associated with estimating dermal exposures resulting from contact with residue-contaminated surfaces. These data will also aid in determining what additional residue transfer data should be collected and what type of microactivity data are needed to estimate dermal and indirect ingestion exposure to residues on household surfaces.
The U.S. Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under contract number 68-D-99-011 to Battelle. It has been subjected to Agency review and approved for publication.
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| JOURNAL |
Exposure of Preschool Children to Chlorpyrifos and Its Degradation Product 3,5,6-Trichloro-2-Pyridinol in Their Everyday Environments |
09/15/2004
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Morgan, M. K., L. Sheldon, C. Croghan, P. A. Jones, G. L. Robertson, J. C. Chuang, N. K. Wilson, AND C. Lyu. Exposure of Preschool Children to Chlorpyrifos and Its Degradation Product 3,5,6-Trichloro-2-Pyridinol in Their Everyday Environments. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY. Nature Publishing Group, London, Uk, 1-13, (2004).
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As part of the Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) study, we investigated the exposures of preschool children to chlorpyrifos and its degradation product 3,5,6-trichloro-2-pyridinol (TCP) in their everyday environments. During this study, the participants were still able to purchase and apply chlorpyrifos at their homes or day care centers. Participants were recruited randomly from 129 homes and 13 day care centers in six North Carolina counties. Monitoring was performed over a 48-h period at the children's homes and/or day care centers. Samples that were collected included duplicate plate, indoor and outdoor air, urine, indoor floor dust, play area soil, transferable residues (PUF roller), and surface wipes (hand, food preparation, and hard floor). The samples were extracted and analyzed by gas chromatography/mass spectrometry. Chlorpyrifos was detected in 100% of the indoor air and indoor floor dust samples from homes and day care centers. TCP was detected at homes and day care centers in 100% of the indoor floor dust and hard floor surface wipe, in >97% of the solid food, and in >95% of the indoor air samples. Generally, median levels of chlorpyrifos were higher than those of TCP in all media, except for solid food samples. For these samples, the median TCP concentrations were 12 and 29 times higher than the chlorpyrifos concentrations at homes and day care centers, respectively. The median urinary TCP concentration for the preschool children was 5.3 ng/mL and the maximum value was 104 ng/mL. The median potential aggregate absorbed dose (ng/kg/day) of chlorpyrifos for these preschool children was estimated to be 3 ng/kg/day. The primary route of exposure to chlorpyrifos was through dietary intake, followed by inhalation. The median potential aggregate absorbed dose of TCP for these children was estimated to be 38 ng/kg/day, and dietary intake was the primary route of exposure. The median excreted amount of urinary TCP for these children was estimated to be 117 ng/kg/day. A full regression model of the relationships among chlorpyrifos and TCP for the children in the home group explained 23% of the variability of the urinary TCP concentrations by the three routes of exposure (inhalation, ingestion, dermal absorption) to chlorpyrifos and TCP. However, a final reduced model via step-wise regression retained only chlorpyrifos through the inhalation route and explained 22% of the variability of TCP in the children's urine. The estimated potential aggregate absorbed doses of chlorpyrifos through the inhalation route were low (median value, 0.8 ng/kg/day) and could not explain most of the excreted amounts of urinary TCP. This suggested that there were other possible sources and pathways of exposure that contributed to the estimated potential aggregate absorbed doses of these children to chlorpyrifos and TCP. One possible pathway of exposure that was not accounted for fully is through the children's potential contacts with contaminated surfaces at homes and day care centers. In addition, other pesticides such as chlorpyrifos-methyl may have also contributed to the levels of TCP in the urine. Future studies should include additional surface measurements in their estimation of potential absorbed doses of preschool children to environmental pollutants. In conclusion, the results showed that the preschool children were exposed to chlorpyrifos and TCP from several sources, through several pathways and routes.
The United States Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under contract #68-D-99-011 to Battelle. It has been subjected to Agency review and approved for publication.
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| JOURNAL |
Air Levels of Carcinogenic Polycyclic Aromatic Hydrocarbons Following the World Trade Center Disaster |
08/10/2004
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Pleil, J. D., A. F. Vette, B. A. Johnson, AND S. M. Rappaport. Air Levels of Carcinogenic Polycyclic Aromatic Hydrocarbons Following the World Trade Center Disaster. PNAS (PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES) 101(32):11685-11688, (2004).
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The catastrophic collapse of the World Trade Center (WTC) on September 11, 2001, created an immense dust cloud followed by fires that emitted soot into the air of New York City (NYC) well into December. The subsequent cleanup used diesel equipment that further polluted the air until the following June. The particulate air pollutants contained mutagenic and carcinogenic polycyclic aromatic hydrocarbons (PAHs). By using an assay developed for archived samples of fine particles, we measured nine PAHs in 243 samples collected at or near Ground Zero from September 23, 2001, to March 27, 2002. Based on temporal trends of individual PAH levels, we differentiated between fire and diesel sources and predicted PAH levels between 3 and 200 d after the disaster. Predicted PAH air concentrations on September 14, 2001, ranged from 1.3 to 15 ng/m3; these values are among the highest reported from outdoor sources. We infer that these high initial air concentrations resulted from fires that rapidly diminished over 100 d. Diesel sources predominated for the next 100 d, during which time PAH levels declined slowly to background values. Because elevated PAH levels were transient, any elevation in cancer risk from PAH exposure should be very small among nonoccupationally exposed residents of NYC. However, the high initial levels of PAHs may be associated with reproductive effects observed in the offspring of women who were (or became) pregnant shortly after September 11, 2001. Because no PAH-specific air sampling was conducted, this work provides the only systematic measurements, to our knowledge, of ambient PAHs after the WTC disaster.
This work is a collaborative effort between the U.S. Environmental Protection Agency and the University of North Carolina and was supported by National Institute for Environmental Health Sciences of the National Institutes of Health Grants P42ES05948 and P30ES10126. The research has been subjected to U.S. Environmental Protection Agency review and approved for publication.
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Environmental Research in Response to 9/11 and Homeland Security |
02/01/2004
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Vette, A. F., S. Gavett, S. G. Perry, D. K. Heist, A. H. Huber, M. N. Lorber, P. J. Lioy, P. Georgopoulos, S. T. Rao, W. B. Petersen, B. Hicks, J. S. Irwin, AND G. J. Foley. Environmental Research in Response to 9/11 and Homeland Security. EM: AIR AND WASTE MANAGEMENT ASSOCIATIONS MAGAZINE FOR ENVIRONMENTAL MANAGERS (February):14-22, (2004).
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The terrorist attacks on September 11, 2001 resulted in a disaster unlike any other on U.S. soil. The collapse of the World Trade Center (WTC) towers and the underground fires that burned for months required the efforts of numerous Federal, State and local agencies as well as universities to provide a better understanding of the impacts of the disaster on the environment and the public's health. The extensive monitoring efforts undertaken by these entities were vital to estimate impacts on public health in the aftermath of the disaster. This paper describes how the U.S. Environmental Protection Agency's Office of Research and Development (EPA-ORD) responded to the WTC disaster with monitoring, modeling and risk assessment.
It is imperative that our nation is prepared to respond to disasters resulting from terrorist attacks and minimize the impact on the public's health. Future attacks may involve the use of agricultural and industrial chemicals, biological warfare and even a "dirty" bomb. These scenarios and others may ultimately entail contaminating the air we breathe, the water we drink and the food we eat - in other words, our environment. To this end, scientists at the U.S. EPA-ORD initiated a research program devoted to Homeland Security issues that began in the aftermath of 9/11.
The United States Environmental Protection Agency (EPA) through its Office of Research and Development produced this research in collaboration with the National Oceanic and Atmospheric Administration (NOAA) through an interagency agreement. This manuscript has been peer reviewed and approved by EPA for publication. This manuscript does not necessarily reflect the views of NOAA or the views and policies of the EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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Air Pollution Measurements in the Vicinity of the World Trade Center Summary of Measurements Conducted By EPA-Ord |
02/01/2004
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Vette, A. F., R. L. Seila, E. C. Swartz, J. D. Pleil, AND L. Webb. Air Pollution Measurements in the Vicinity of the World Trade Center Summary of Measurements Conducted By EPA-Ord. EM: AIR AND WASTE MANAGEMENT ASSOCIATIONS MAGAZINE FOR ENVIRONMENTAL MANAGERS (February):23-26, (2004).
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The U.S. Environmental Protection Agency's Office of Research and Development (EPA-ORD) was requested by EPA's Region 2 office in New York on 9/12/01 to assist with air quality monitoring in response to the collapse of the World Trade Center. Scientists at the U.S. EPA-ORD's National Exposure Research Laboratory (NERL) quickly assembled a field team and prepared monitoring equipment to be used in the response. The NERL field team traveled from Research Triangle Park, NC and arrived in New York on 9/16/01. There we coordinated with the Emergency Response Team (ERT) headed by the U.S. Coast Guard and outlined a monitoring strategy to support the efforts of the ERT. The ERT also worked closely with the U.S. EPA Office of Air Quality Planning and Standards to set up an asbestos monitoring network in lower Manhattan.
Because the full extent of the hazards associated with the WTC were not yet known, we set out to characterize the on-going emissions associated with the fires and the materials generated during debris removal, especially particulate matter (PM). The initial collapse of the WTC towers produced in excess of one million tons of pulverized debris and combusted materials - both respirable and non-respirable PM including asbestos fibers and other potentially irritating materials - that blanketed lower Manhattan. Debris removal was likely to resuspend respirable sized PM (< 10 micrometers, PM10), which could migrate into inhabited portions of the city and, therefore, it was important to characterize the levels of pollutants in the settled dust as well. The smoldering fires generated products of incomplete combustion including partially oxygenated organic compounds and polycyclic aromatic hydrocarbons (PAHs), as well as fine PM (< 2.5 micrometers, PM2.5), which can penetrate deep into the lungs.
This paper summarizes the efforts undertaken by the U.S. EPA-ORD in response to the World Trade Center and presents results on the monitored air pollutants. Some recommendations are made regarding future directions in air monitoring in response to environmental disasters, such as terrorist attacks.
The United States Environmental Protection Agency (EPA) through its Office of Research and Development produced the research described here. This manuscript has been peer reviewed and approved by EPA for publication. This manuscript does not necessarily reflect the views and policies of the EPA.
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| JOURNAL |
Preface: Special Issue of Aerosol Science and Technology for Particulate Matter: Atmospheric Sciences, Exposure and the Fourth Colloquium on PM and Human Health |
08/01/2004
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Ondov, J., C. Davidson, AND P. A. Solomon. Preface: Special Issue of Aerosol Science and Technology for Particulate Matter: Atmospheric Sciences, Exposure and the Fourth Colloquium on PM and Human Health. AEROSOL SCIENCE AND TECHNOLOGY. American Association for Aerosol Research, 38(S2):1-2, (2004).
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There is no abstract available for this product. If further information is needed, please refer to the bibliographic citation and contact the person listed under contact field.
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| JOURNAL |
Preface: Special Section of the Journal of Air & Waste Management Association for Particulate Matter: Atmospheric Sciences, Exposure and the Fourth Colloquium on PM and Human Health |
09/01/2004
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Chow, J. C., R. Scheffe, AND P. A. Solomon. Preface: Special Section of the Journal of Air & Waste Management Association for Particulate Matter: Atmospheric Sciences, Exposure and the Fourth Colloquium on PM and Human Health. JOURNAL OF AIR AND WASTE MANAGEMENT ASSOCIATION. Air & Waste Management Association, Pittsburgh, PA, 54(9):1025, (2004).
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This dedicated issue of the Journal of the Air & Waste Management Association contains 17 peer-reviewed scientific papers that were presented at the specialty conference, “Particulate Matter: Atmospheric Sciences, Exposure and the Fourth Colloquium on PM and Human Health,” that was held in April 2003 in Pittsburgh, PA. Other peerreviewed
papers appear in companion issues of the Journal of Geophysical Research –Atmospheres; Aerosol Science and Technology; Atmospheric Environment; and Inhalation Toxicology, all being published in the last half of 2004. More than 450 papers were presented in platform and poster sessions at the meeting, the overall goal of which
was to bring together health and exposure scientists with atmospheric scientists, air quality managers, and policy makers to allow for enhanced communications and exchange of information among these groups. It is estimated that nearly 100 peerreviewed papers will be published.
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| JOURNAL |
Radiocarbon Measurement of the Biogenic Contribution to Summertime PM 2.5 Ambient Aerosol in Nashville, Tn |
11/01/2004
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Lewis, C. W., G. A. Klouda, AND W. D. Ellenson. Radiocarbon Measurement of the Biogenic Contribution to Summertime PM 2.5 Ambient Aerosol in Nashville, Tn. ATMOSPHERIC ENVIRONMENT 38(35):6054-6061, (2004).
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Radiocarbon (14C) measurements performed on PM-2.5 samples collected near Nashville, TN from June 21 to July 13, 1999, showed high levels of modern carbon, ranging from 56 to 80% of the total carbon in the samples. Radiocarbon measurements performed on dichloromethane extracts of a subset of the samples showed modern carbon levels that were on average only 9% smaller than those for total carbon. A new approach based on the Chapman-Richards model of tree growth was used to define the quantitative relationship between measurements of 'percent modern carbon' and inferred 'percent biogenic carbon.' The results of this study contribute to a growing body of evidence (including measurements of radiocarbon, organic carbon to elemental carbon ratios and organic tracer species, as well as results from Chemical Mass Balance and air quality simulation modeling) in support of the importance of biogenic secondary organic aerosol (SOA) in the Southeastern U.S during summer.
The United States Environmental Protection Agency through its Office of Research and Development managed and partially funded the research described here under Contract 68D50049 to ManTech Environmental Technology, Inc., and Interagency Agreement DW13937923 to the National Institute of Standards and Technology, which also contributed to the funding. It has been subjected to Agency review and approved for publication. Certain commercial equipment, instruments, or materials are identified in this paper to specify adequately the experimental procedure. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials and equipment identified are necessarily the best available for the purpose.
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| JOURNAL |
Using 19f-Nmr Spectroscopy to Determine Trifluralin Binding to Soil |
11/12/2004
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Strynar, M. J., J. Dec, A. Benesi, A. D. Jones, R. A. FRY, AND J. BOLLAG. Using 19f-Nmr Spectroscopy to Determine Trifluralin Binding to Soil. ENVIRONMENTAL SCIENCE AND TECHNOLOGY. American Chemical Society, Washington, DC, 38(24):6645-6655, (2004).
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Trifluralin is a widely used herbicide for the control of broad leaf weeds in a variety of crops. Its binding to soil may result in significant losses in herbicidal activity and a delayed pollution problem. To investigate the nature of soil-bound trifluralin residues, 14C-labeled herbicide was incubated for 7 weeks with four soils under anoxic conditions. As determined by radiocounting, trifluralin binding ranged between 10 and 53% of the initial 14C depending on the soil tested. 19F NMR analyses of the methanol extracts and different fractions of the extracted soil suggested that bound residue formation largely involved reduced metabolites of the herbicide. A 2,6-diamino product of trifluralin reduction with zero-valent iron (Fe-TR), and the standard of a 1,2-diamino trifluralin derivative (TR6) formed covalent bonds with fulvic acid (FA), as indicated by the 19F NMR spectra taken periodically over a 3-week contact time. At short contact times, TR6 and Fe-TR formed weak physical bonds with FA, as the respective spin-spin relaxation times (T1) decreased from 1300-1831 msec for TR6 or Fe-TR analyzed in the absence of FA to 150-410 msec for TR6/FA or Fe-TR/FA mixtures. In general, the results indicated that trifluralin immobilization involved a variety of mechanisms (covalent binding, adsorption, sequestration), and with time it became increasingly stable.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| JOURNAL |
Determinants of Temporal Variability in NHEXAS-Maryland Environmental Concentrations, Exposures, and Biomarkers |
12/15/2004
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Egeghy, P. P., J. J. Quackenboss, S. N. Catlin, AND B. Ryan. Determinants of Temporal Variability in NHEXAS-Maryland Environmental Concentrations, Exposures, and Biomarkers. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY. Nature Publishing Group, London, Uk, (12):1-10, (2004).
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The longitudinal NHEXAS-Maryland study measured metals, PAHs, and pesticides in several media to capture temporal variability. Questionnaires were concurrently administered to identify factors that influenced changes in contaminant levels over time. We constructed mixed-effects regression models for lead, phenanthrene, and chlorpyrifos (including metabolites) in indoor air, dust, dermal wipes, and biological fluids. Significant predictors represented time-varying activities as well as unchanging housing and demographic factors. There was little overlap among the models, with predictors generally reflecting the diverse characteristics of the target compounds. We estimated between- and within-person variance components to evaluate the reliability of the measurements. While only one measurement of lead in blood or chlopyrifos in dust was needed for a dependable estimate of an individual's average level, three to eight measurements were needed for most other compound/exposure medium combinations because of considerable temporal variability. Measurements in biological fluids and dust were generally more consistent than those in indoor air. The significant covariates in the full models preferentially reduced the between-person variance component. Since the regression models explained only 1 to 37% of the within-person variance, the questionnaires in this study provided only modest insight into the factors responsible for the temporal variability in the contaminant levels.
The U.S. Environmental Protection Agency through its Office of Research and Development funded, managed, and collaborated in the research described here under NHEXAS Cooperative Agreement no. CR822038-1 to Harvard University, Johns Hopkins University, Emory University, Southwest Research Institute, and Westat. It has been subjected to Agency review and approved for publication.
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| JOURNAL |
Limitations on the Uses of Multimedia Exposure Measurements for Multipathway Exposure Assessment Part II: Effects of Missing Data and Imprecision |
12/01/2004
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CLAYTON, C. A., P. L. MOSQUIN, E. D. PELLIZARRI, AND J. J. QUACKENBOSS. Limitations on the Uses of Multimedia Exposure Measurements for Multipathway Exposure Assessment Part II: Effects of Missing Data and Imprecision. QUALITY ASSURANCE: GOOD PRACTICE, REGULATION, AND LAW. Taylor & Francis, Inc., Philadelphia, PA, 10(3-4):123-159, (2004).
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Multimedia data from two probability-based exposure studies were investigated in terms of how missing data and measurement-error imprecision affected estimation of population parameters and associations. Missing data resulted mainly from individuals' refusing to participate in certain measurement activities, rather than from field or laboratory problems; it suggests that future studies should focus on methods for maximizing participation rates. Measurement error variances computed from duplicate-sample data were small relative to the inherent variation in the populations; consequently, adjustments in nonparametric percentile estimates to account for measurement imprecision were small. Methods of adjustment based on lognormality assumptions, however, appeared to perform poorly.
The United States Environmental Protection Agency through its Office of Research and Development funded and collaborated in the research described here under contract number 68-D-99-008 and assistance agreement number CR821902 to Research Triangle Institute. It has been subjected to Agency review and approved for publication.
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| JOURNAL |
Limitations on the Uses of Multimedia Exposure Measurements for Multipathway Exposure Assessment Part I: Handling Observations Below Detection Limits |
12/01/2004
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CLAYTON, C. A., P. L. MOSQUIN, E. D. PELLIZARRI, AND J. J. QUACKENBOSS. Limitations on the Uses of Multimedia Exposure Measurements for Multipathway Exposure Assessment Part I: Handling Observations Below Detection Limits. QUALITY ASSURANCE: GOOD PRACTICE, REGULATION, AND LAW. Taylor & Francis, Inc., Philadelphia, PA, 10(3-4):123-159, (2004).
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Multimedia data from two probability-based exposure studies were investigated in terms of how censoring of non-detects affected estimation of population parameters and associations. Appropriate methods for handling censored below-detection-limit (BDL) values in this context were unclear since sampling weights were involved and since bivariate associations/measures were of interest. Both simple substitution (e.g., using to = or 2/3 of the detection limit (DL) for BDL values) and truncation-based strategies were investigated by creating some artificial DLs and comparing resultant estimates with the original studies' uncensored results. The substitution methods generally outperformed the truncation methods, with the (2/3)DL substitution generally performing best.
The United States Environmental Protection Agency through its Office of Research and Development funded and collaborated in the research described here under contract number 68-D-99-008 and assistance agreement number CR821902 to Research Triangle Institute. It has been subjected to Agency review and approved for publication.
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| JOURNAL |
Multi-Site Field Evaluation of Candidate Samplers for Measuring Coarse-Mode PM |
12/01/2004
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VANDERPOOL, R., T. G. ELLESTAD, T. HANLEY, R. SCHEFFE, P. A. SOLOMON, C. NOBLE, S. NATARAJAN, R. MURDOCH, J. AMBS, G. SEM, AND J. TISCH. Multi-Site Field Evaluation of Candidate Samplers for Measuring Coarse-Mode PM. EM: AIR AND WASTE MANAGEMENT ASSOCIATIONS MAGAZINE FOR ENVIRONMENTAL MANAGERS. Air & Waste Management Association, Pittsburgh, PA, 6-7, (2004).
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In response to expected changes to the National Ambient Air Quality Standards for particulate matter, comprehensive field studies were conducted to evaluate the performance of sampling methods for measuring coarse mode aerosols (i.e. PMc). Five separate PMc sampling approaches were evaluated at three sampling sites selected to provide diverse challenges to the samplers with respect to aerosol concentration, aerosol particle size distribution, and aerosol composition. The candidate samplers evaluated included both traditional filter based samplers as well as near real-time, continuous monitors. Results showed that the various sampler designs provided repeatable responses and showed potential for measuring PMc concentrations with some degree of confidence. EPA is currently working with the sampler manufacturers in an effort to improve the accuracy of their respective sampler designs. Once appropriate design and/or operational improvements are identified and implemented, it is expected that follow-up field studies will be conducted.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| JOURNAL |
Pesticides and Lung Cancer Risk in the Agricultural Health Study |
11/01/2004
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ALAVANJA, M. C., M. DOSEMECI, C. SAMANIC, J. LUBIN, C. F. LYNCH, C. KNOTT, J. BARKER, J. HOPPIN, D. SANDLER, J. COBLE, K. W. THOMAS, AND A. BLAIR. Pesticides and Lung Cancer Risk in the Agricultural Health Study. AMERICAN JOURNAL OF EPIDEMIOLOGY. Johns Hopkins Bloomberg School of Public Health, 160(9):876-885, (2004).
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We examined the relationship between 50 widely used agricultural pesticides and lung cancer incidence in the Agricultural Health Study, a prospective cohort study of 57,284 pesticide applicators, and 32,333 spouses of farmer applicators with no prior history of lung cancer. Self-administered questionnaires were completed at enrollment (1993-1997). Cancer incidence was determined through population-based cancer registries from enrollment through December 31, 2001. A lung cancer SIR of 0.44 (95% CI, 0.39-0.49) was observed overall, due, in large part, to a low cigarette smoking prevalence. Two widely used herbicides, metolachlor and pendimethalin (odds ratios for low-exposed groups to higher exposure categories [OR=1.0, 1.6, 1.2, 5.0 p for trend=0.0001; and OR= 1.0, 1.6, 2.1, 4.4; p for trend p=0.002, respectively]) and two widely used insecticides chlorpyrifos and diazinon (OR=1.0, 1.1, 1.7, 1.9; p for trend=0.03 and OR= 1.0, 1.6, 2.7, 3.7; p for trend =0.0.04, respectively) showed some evidence of exposure-response for lung cancer. These excesses could not be explained by previously identified lung cancer risk factors. The usage levels in this cohort are considerably higher than those typically experienced by the general population. An excess risk among spouses, directly exposed to pesticides could not be evaluated at this time.
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| PRESENTATION |
EPA Compendium Methods to-15, to-15 Supplement, and to-17 for Monitoring Vocs in Air |
05/13/2004
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McClenny, W. A. EPA Compendium Methods to-15, to-15 Supplement, and to-17 for Monitoring Vocs in Air. Presented at Environmental Professionals Organizationof Connecticut, Hartford, CT, May 13, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Laboratory and Field Evaluation of Instrumentation for the Semi-Continuous Determination of Particulate Nitrate (and Other Water-Soluble Particulate Components) |
06/23/2004
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Long, R. W. AND W. A. McClenny. Laboratory and Field Evaluation of Instrumentation for the Semi-Continuous Determination of Particulate Nitrate (and Other Water-Soluble Particulate Components). Presented at Air & Waste Management Conference, Indianapolis, IN, June 22-25, 2004.
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Studies conducted at the EPA facility in Research Triangle Park, NC and at a field study in Southern California have demonstrated the capability for the semi-continuous determination of particulate nitrate (and other water soluble ionic species). Two instruments, a R&P 8400N particulate nitrate monitor and an ion chromatography (IC)-based prototype monitor developed at Texas Tech University (TTU), were evaluated both in the laboratory using a simulated ambient aerosol and in the field (Rubidoux, CA) during a three week joint ambient comparison study with Brigham Young University (BYU) and the South Coast Air Quality Monitoring District (SCAQMD). During the initial laboratory studies, both instruments were responsive to changes in the simulated aerosol concentration. However, potential problems were discovered involving both instruments during the laboratory based studies and these problems are currently being addressed. Both instruments were then transported to the SCAQMD Rubidoux field site and operated for a period of three weeks (July 1-21, 2003). Due to manufacturer's quality assurance issues associated with IC components of the TTU prototype instrument, limited data were obtained from this instrument during the three week sampling period. Initial comparisons show general agreement between the R&P and IC-based prototype instruments for the semi-continuous determination of ambient particulate nitrate at lower nitrate concentrations (<15 ug/m3) and an under determination by the R&P instrument at higher concentrations (>15 ug/m3). During the three week study period, 15-minute average particulate nitrate concentrations approaching 30 ug/m3 were observed. Semi-continuous results obtained from the EPA-operated instruments were averaged and compared to integrated sampler results obtained by BYU and SCAQMD. Results of the laboratory and field studies will be addressed.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Towards a Generic PBPK Model of Pyrethroid Pesticides: Modeling Deltamethrin and Permethin in the Rat |
03/22/2004
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TORNERO-VELEZ, R., H. Nichols, M. V. Evans, M. J. DeVito, M. J. DeVito, M. Dellarco, J. N. Blancato, AND K. G. Anlauf. Towards a Generic PBPK Model of Pyrethroid Pesticides: Modeling Deltamethrin and Permethin in the Rat. Presented at 43rd Annual Meeting of the Society of Toxicology, Baltimore, MD, March 21-25, 2004.
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Pyrethroids have emerged as a major class of insecticide due to their selective potency in insects and their relatively low potency in mammalian studies. Pyrethroids exert toxicity by binding to voltage-gated sodium channels, thereby eliciting excitatory neurotoxicity. The Food Quality Protection Act (FQPA) of 1996 requires the US EPA to consider the cumulative effects (multiple chemicals by aggregate routes of exposure) of pesticides having a common mechanism of toxicity. In such evaluations it is necessary to accurately estimate the dose available to critical tissues. Towards this end, studies examining the pharmacokinetics of permethrin and deltamethrin in rodents were used to derive a common PBPK model structure. The model included skin, fat, liver, brain, and lumped tissue compartments. Physiological values were obtained from the literature. Tissue-blood partition coefficients were based on Log P and tissue composition. Diffusion-limited tissue uptake in all tissues provided a better visual fit to the data than flow-limited kinetics. Apparent coefficients of permeability were held constant for both Pyrethroids at 5% of tissue flow for fat and muscle tissues, 2% for brain tissue, and 0.2% for richly perfused tissue. While the terminal half life of deltamethrin in blood was 2.5 times longer than permethrin, the kinetics of these two pyrethroids were adequately described by the same model structure. This initial modeling exercise suggests that the kinetics of other pyrethroids may be described by a common model structure. This may allow the development of a single unified PBPK model for use in the cumulative risk assessment ofpyrethroid pesticides.
This work has been funded by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.
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| PRESENTATION |
Towards a Generic PBPK Model of Pyrethroid Pesticides: Modeling Deltamethrin and Permethrin in the Rat |
03/23/2004
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TORNERO-VELEZ, R., H. P. Nichols, M. V. Evans, M. J. DeVito, C. C. Dary, M. Dellarco, AND J. Blancato. Towards a Generic PBPK Model of Pyrethroid Pesticides: Modeling Deltamethrin and Permethrin in the Rat. Presented at Society of Toxicology, Baltimore, MD, March 21-25, 2004.
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Pyrethroids have emerged as a major class of insecticide due to their selective potency in insects and their relatively low potency in mammalian studies. Pyrethroids exert toxicity by binding to voltage-gated sodium channels, thereby eliciting excitatory neurotoxicity. The Food Quality Protection Act (FQPA) of 1996 requires the US EPA to consider the cumulative effects (multiple chemicals by aggregate routes of exposure) of pesticides having a common mechanism of toxicity. In such evaluations it is necessary to accurately estimate the dose available to critical tissues. Towards this end, studies examining the pharmacokinetics of permethrin and deltamethrin in rodents were used to derive a common PBPK model structure. The model included skin, fat, liver, brain, and lumped tissue compartments. Physiological values were obtained from the literature. Tissue-blood partition coefficients were based on Log P and tissue composition. Diffusion-limited tissue uptake in all tissues provided a better visual fit to the data than flow-limited kinetics. Apparent coefficients of permeability were held constant for both pyrethroids at 5% of tissue flow for fat and muscle tissues, 2% for brain tissue, and 0.2% for richly perfused tissue. While the terminal half life of deltamethrin in blood was 2.5 times longer than permethrin, the kinetics of these two pyrethroids were adequately described by the same model structure. This initial modeling exercise suggests that the kinetics of other pyrethroids may be described by a common model structure. This may allow the development of a single unified PBPK model for use in the cumulative risk assessment of pyrethroid pesticides.
This work has been funded by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.
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| PRESENTATION |
A Comprehensive Approach for Physiologically Based Pharmacokinetic (PBPK) Models Using the Exposure Related Dose Estimating Model (Erdem) System |
03/22/2004
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Ruiz, A., A. Tsang, J. Licitra, F. W. Power, J. N. Blancato, AND C. C. Dary. A Comprehensive Approach for Physiologically Based Pharmacokinetic (PBPK) Models Using the Exposure Related Dose Estimating Model (Erdem) System. Presented at 43rd Annual Meeting of the Society of Toxicology, Baltimore, MD, March 21-25, 2004.
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The implementation of a comprehensive PBPK modeling approach resulted in ERDEM, a complex PBPK modeling system. ERDEM provides a scalable and user-friendly environment that enables researchers to focus on data input values rather than writing program code. ERDEM efficiently manages these inputs and provides reporting and model output assessment capabilities, for toxicologists, risk assessors, exposure scientists and managers. As PBPK models grow in complexity, the implementation of models, the preparation and maintenance of inputs, and the assessment of model output results has become more tedious and error prone.
Combining this experience with intensive research produced a comprehensive modeling approach for designing ERDEM and other PBPK modeling projects. The goal of this modeling approach is to improve the modeling process from planning to application for multi-media exposure assessments. The core activities for this approach include identification and implementation of the model design and performance criteria, the model hardware/software specifications, and the model testing and evaluation.
As a comprehensive modeling system, ERDEM contains a PBPK model engine component that can create scenario-based simulations and target dose estimates in multiple compartments for exposure of a species to multiple chemicals and metabolites. The input management component uses a Windows based graphical user interface and relational database, enabling the user to enter, edit, report, and export data sets of user assigned physiological information. The stochastic component evaluates the uncertainty associated with input parameters and output model results. ERDEM replaces the traditional program-oriented modeling approach, which is error prone, with a sophisticated and user-friendly model simulation and data management system.
This work has been funded by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.
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| PRESENTATION |
EPA's PM Supersites Program, Communication Strategy |
05/14/2004
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Solomon, P. A. EPA's PM Supersites Program, Communication Strategy. Presented at States Air Monitoring Working Group, Point Clear, AL, May 13-15, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
(State Monitoring Working Group)COMPARISON of the Stn and Improve Networks for Mass and Selected Chemical Components |
05/14/2004
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Solomon, P. A., T. KlamserWilliams, P. P. Egeghy, D. Crumpler, AND J. Rice. (State Monitoring Working Group)COMPARISON of the Stn and Improve Networks for Mass and Selected Chemical Components. Presented at State Air Monitoring Working Group, Point Clear, AL, May 13-15, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Multi-Site Performance Evaluations of Candidate Methodologies for Determining Coarse Particulate Matter (Pmc) Concentrations |
04/20/2004
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Vanderpool, R., T. G. Ellestad, P. A. Solomon, M. K. Harmon, R. B. Zweidinger, T. Hanley, R. Scheffe, B. Murdoch, S. Natarajan, C. A. Noble, J. Ambs, G. Sem, AND J. Tisch. Multi-Site Performance Evaluations of Candidate Methodologies for Determining Coarse Particulate Matter (Pmc) Concentrations. Presented at Symposium on Air Quality Measurement Methods and Technology, Research Triangle Park, NC, April 20-22, 2004.
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Comprehensive field studies were conducted to evaluate the performance of sampling methods for measuring the coarse fraction of PM10 in ambient air. Five separate sampling approaches were evaluated at each of three sampling sites. As the primary basis of comparison, a discrete difference method was used which employs two designated FRM samplers, one to measure PM2.5 and the other PM10. The numerical difference of these reference method concentrations (PM10-PM2.5) represented an estimate of PMc. A second sampling approach involved a sequential dichotomous sampler, which provided both PM2.5 and PMc measurements. In both of these filter-based, time-integrated measurement approaches, the collected aerosol mass was analyzed gravimetrically in the laboratory under controlled conditions. Three continuous coarse particle samplers that measure PMc directly with a time resolution of 1 hour or less were also evaluated. One such sampler was a commercially available system based on beta attenuation, the second was based on TEOM technology. Both of these measurement approaches used dichotomous virtual impactors for separating fine and coarse particles. The third real-time sampler evaluated was an aerodynamic particle sizer (APS) that measures the aerodynamic diameter of individual particles, calculates the mass of the particle based on an assumed particle density, then sums the mass within the size range of interest to estimate the PMc mass concentration.
Sampling sites and timing of the studies were selected to provide diverse challenges to the samplers with respect to aerosol concentration, aerosol particle size distribution, and aerosol composition. Results from performance evaluations of the candidate PMc samplers at Gary, IN, Phoenix, AZ, and Riverside, CA will be presented.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Comparison of Measurements of Ambient Particle Nitrate With Semi-Continuous Instruments |
04/20/2004
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Long, R. W. AND W. A. McClenny. Comparison of Measurements of Ambient Particle Nitrate With Semi-Continuous Instruments. Presented at Symposium on Air Quality Measurement Methods and Technology, Research Triangle Park, NC, April 20-22, 2004.
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Comparisons between two different semi-continuous monitors of ambient level particulate nitrate are interpreted for both field and laboratory studies. One instrument involves thermal desorption of particulate nitrate to form a combination of NO and NO2 gases which are detected as NO in a chemiluminescence monitor. The second instrument involves the collection of particulate nitrate in a mist chamber with subsequent analysis of nitrate ions by ion chromatography. Ambient measurements in Rubidoux, CA during July, 2003 as well as measurements in the research laboratories at the Research Triangle Park, NC indicate the occurrence of response saturation related to particulate water content. These experimental results are interpreted.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Evaluation and Use of Stand-Alone Commercial Photolytic Converters for NO2 to No Conversion |
04/20/2004
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Kronmiller, K. G. AND W. A. McClenny. Evaluation and Use of Stand-Alone Commercial Photolytic Converters for NO2 to No Conversion. Presented at Symposium on Air Quality Measurement Methods and Technology, Research Triangle Park, NC, April 20-22, 2004.
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Two types of stand-alone commercial photolytic converters of NO2 to NO are now available for use with NO, O3 chemiluminescence monitors for the measurement of NO2. Both units have been tested for interferences resulting from photolysis of HONO or from decomposition of PAN. One unit is based on the use of a broadband source and incorporates a source cooler. This unit has been used for two month-long field studies, one in May of 2002 and a second in October 2003. The results indicate that the converter is robust and reliable with conversion efficiencies of of 35 to 70% depending on the air flow rate through the converter. The second commercial unit is based on a LED array with output emission wavelength at 390 to 400 nm. This unit is being field tested for use as part of on-going tests. Based on results so far the prospect of using one of the stand-along converters with an external, heated metal converter and a chemiluminescence monitor to measure NO, NO2, and NOy seems reasonable.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Laboratory and Field Evaluation of Crystallized Dow 704 Oil on the Performance of the PM2.5 Wins Fractionator |
04/20/2004
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Vanderpool, R., M. Labickas, A. Leston, M. Tolocka, F. McElroy, R. Murdoch, S. Natarajan, C. A. Noble, L. Byrd, R. W. Wiener, AND E. Hunike. Laboratory and Field Evaluation of Crystallized Dow 704 Oil on the Performance of the PM2.5 Wins Fractionator. Presented at Symposium on Air Quality Measurement Methods and Technology, Research Triangle Park, NC, April 20-22, 2004.
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Subsequent to the PM2.5 FRM's 1997 promulgation, technicians at the CT Dept. of Env. Protection observed that the DOW 704 diffusion oil used in the method's WINS fractionator would occasionally crystallize during field use - particularly under wintertime conditions. While the frequency of occurrence on a nationwide basis was judged to be low, concerns were raised that crystallization of the oil during a given sampling event may adversely affect the event's data quality.
In response to these concerns, the USEPA and the CT Dept. of Env. Protection conducted a specialized series of tests to determine if crystallized oil adversely affected the performance of the WINS fractionator. In the laboratory, an experimental setup using dry ice was used to artificially induce crystallization of the diffusion oil under controlled conditions. Standard size selective tests of the WINS fractionator were then conducted using primary calibration aerosols. Test results showed that neither the position nor shape of the WINS fractionation curve were substantially influenced by crystallization of the DOW 704 oil.
Wintertime field tests were then conducted in Windsor, CT using collocated FRMs equipped with both crystallized and non-crystallized oil. As predicted by results of the laboratory tests, crystallization of the oil did not adversely affect measured PM2.5 concentrations. In 33 collocated PM2.5 tests, regression of crystallized DOW 704 versus liquid DOS (dioctyl sebacate) produced slopes, intercepts, and R2 values of 0.98, 0.1 ug/m3, and 0.997, respectively.
In 45 collocated PM2.5 tests conducted at three U.S. cities, regression of liquid DOS versus liquid DOW 704 produced slopes, intercepts, and R2 values of 0.995, -0.006 ug/m3, and 0.999, respectively. As a result of these tests, DOS oil has been approved by EPA as a substitute for the ' DOW 704 oil. Users of this alternative oil have not reported any operational problems associated with its field use.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
24-Hour Diffusive Sampling of 1,3-Butadiene in Air Onto Carbonpak X Solid Adsorbent With Themal Desorption/Gc/MS Analysis Feasibility Studies |
04/20/2004
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McClenny, W. A., K. D. Oliver, H. H. Jacumin Jr., E. H. Daughtrey Jr., AND D. A. Whitaker. 24-Hour Diffusive Sampling of 1,3-Butadiene in Air Onto Carbonpak X Solid Adsorbent With Themal Desorption/Gc/MS Analysis Feasibility Studies. Presented at Symposium on Air Quality Measurement Methods & Technology, Research Triangle Park, NC, April 20-22, 2004.
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| Abstract:
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Diffusive sampling of 1,3-butadiene for 24 hours onto the graphitic adsorbent Carbopack X contained in a stainless steel tube badge (6.3 mm OD, 5 mm ID, and 90 mm in length) with analysis by thermal desorption/GC/MS has been evaluated in controlled tests. A test matrix of 42 trace level volatile organic compounds in humidified zero air was established by dynamic dilution of compressed gas standards flowing through an environmental chamber. Conditions for automated thermal desorption of the badge including pre-desorption dry purge, and for GC/MS analyses (column flow rate and temperature programming profile) were optimized for specificity, precision, and sensitivity of response. Analytical system responses for sets of tubes exposed to a given 1,3-butadiene concentration were typically precise, e.g. a % RSD < 10% at 1.1 ug/m3 (0.5 ppbv at STP) and system responses were approximately linear with concentration over the range 0 - 9 \ug. No systematic variations of response were observed for changes in sample humidity and temperature (35% to 75% RH at 16,20, and 29 degrees C). Reverse diffusion of 1,3-butadiene into clean air over 12 hours after an initial 12 hour exposure at 9.0 ug/m3 gave a 11% response decrease. Adding 2 ug/m3 (100 ppbv at STP) of ozone during the second twelve hours caused no additional response change.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Detroit Exposure and Aerosol Research Study |
02/26/2004
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Williams, R. W., A. W. Rea, AND L. S. Sheldon. Detroit Exposure and Aerosol Research Study. Presented at Internantional Joint Commission on U.S.-Canada Border, Windsor, Canada, February 26, 2004.
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The DEARS is a three-year field monitoring study that will be conducted in Detroit, Michigan and is designed to measure exposure and describe exposure relationships for air toxics, PM components, PM from specific sources, and criteria pollutants. Detroit, Michigan was considered the best candidate for this study because of its current and projected future non-attainment status for PM2.5, the number of point and mobile source influences present, its geographic location, meteorology, ambient monitoring networks, potential state and local collaborations, and community-based partnerships.
Monitoring will focus primarily on the residence. Study participants and households will be identified through a step-wise approach involving identifying census blocks with and without impacts from local point and/or mobile sources based on prevailing wind direction and then targeting individual households for recruitment into the study. Individual census tracts and blocks will be identified by evaluating available data on the location and emissions from various sources, ambient air concentrations and housing stock. Once census tracts/blocks are identified we will work through existing community action groups in Detroit and the surrounding area to assist with contacting individual households. Partnering with community groups will be important in making connections with residents and communicating the purpose of the study.
Residences will be selected based on proximity to sources. Residences in seven ambient source-impacted areas (mobile sources, point sources, and a control) will be monitored for 5 days in each of 2 seasons (summer, winter). A total of 120 residences will be monitored over 3 years for a total of 1200 household-person/days. A combination of both weekday and weekend sampling will be conducted in order to evaluate expected variations in industrial source emissions, traffic volumes, and personal activities. A Speciation Trends Network site, Allen Park, has been selected as the central site monitor for this study. In addition, one residential outdoor location will be selected each week to serve as a secondary, or rotating, community site. These data will be used to determine how representative the primary and secondary community measures (Allen Park and the selected residential outdoor sites) are relative to all other outdoor locations. Monitoring is anticipated to start in the summer of 2004.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Detroit Exposure and Aerosol Research Study Master Slide Set |
03/30/2004
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Williams, R. W., A. W. Rea, AND L. S. Sheldon. Detroit Exposure and Aerosol Research Study Master Slide Set. Presented at EPA Region V, Chicago, IL, March 30, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
The Detroit Exposure and Aerosol Research Study |
06/21/2004
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Williams, R. W. The Detroit Exposure and Aerosol Research Study. Presented at Joint U.S.-Canadian Research Meeting, Detroit, MI, June 21, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
The Detroit Exposure and Aerosol Research Study (Dears) |
06/29/2004
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Williams, R. W., A. F. Vette, H. Wilson, A. W. Rea, C. Croghan, C. Stevens, AND L. S. Sheldon. The Detroit Exposure and Aerosol Research Study (Dears). Presented at DEARS Community Kick-off Meeting, Detroit, MI, June 29, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
The Detroit Exposure and Areosol Research Study-Dears |
11/17/2004
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The Detroit Exposure and Areosol Research Study-Dears. Presented at The Health and Environmental Canada/USEPA Meeting on Detroit Windsor Health and Exposure Studies, Windsor, Ontario, Canada, November 17, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Pesticide Trade Names and Their Active Ingredients in the Ahs |
02/26/2004
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Coble, J., R. Allen, Y. Ng, S. Nako, B. Suhre, J. A. Hoppin, K. W. Thomas, AND C. Hines. Pesticide Trade Names and Their Active Ingredients in the Ahs. Presented at AHS National Advisory Panel Meeting, Bethesda, MD, February 26-27, 2004.
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The detailed information on the use of specific pesticides is a major strength of exposure assessment conducted for the Agricultural Health Study (AHS). During the enrollment interviews, a check list was used to collect information on the frequency and duration of use for 28 pesticides. The same information on an additional 22 pesticides was also collected for a subset of applicators. During Phase II of the AHS, computer-aided telephone interviews (CATI) were conducted with over 32,000 applicators. Each applicator was asked to report the names of all pesticides that they personally applied to crops, to animals, and applied for non-crop applications, such as treatment of fence rows and buildings. Using an open-ended response format, over 4200 unique pesticide names were reported and entered verbatim into a computer database. These verbatim responses included a mix of pesticide trade names, common names, technical or chemical names, or in some cases, general names or descriptions of the pesticides used. Pesticides with different trade names may contain the same active ingredients, and conversely, pesticides with similar trade names may contain completely different active ingredients. Also, many pesticides contain several active ingredients. The standardization of these pesticide names was necessary to identify their active ingredients, however, the large number of different pesticide names reported by the applicators created a major challenge.
The Pesticide Product Information System (PPIS) is a large database maintained by the US EPA Office of Pesticide Programs (OPP) of all pesticide products registered in the United States. The database includes information on product names, distributor brand names, chemical ingredients, toxicity category, site/pest uses, pesticide type, formulation code, and registration status. Every active ingredient in list of pesticide in the PPIS is assigned a PC Code. Since many active ingredients may have more than one chemical name or synonym, the PC Code serves as a unique identifier to link product trade names with a specific active ingredient. The PPIS was used as a reference source to identify the active ingredients based on the product trade names. In addition to the PPIS, the 2003 Crop Protection Handbook (CPH), formerly known as the Farm Chemicals Handbook, was used to identify commercially available pesticide product trade names along with their active ingredients.
During the CATI interview, the applicator was asked to report all pesticides applied by crop, by animal and by non-crop applications, and therefore, the same pesticide name could be mentioned multiple times by the same applicator. The first step in the standardization process was to generate a list of every unique verbatim name reported by all the applicators, along with the total number of times the verbatim name was reported. The verbatim pesticide names were then cross referenced with the product trade names listed in either the PPIS or the CPH. In some cases, the verbatim name matched exactly with a recognized trade name. In other cases, it was necessary to standardize minor differences in the spelling, punctuation, formulation suffix, or the manufacturer's name in the verbatim pesticide name to match a specific recognized trade name, and a set of codes were used to identify verbatim responses that required standardization.
For some responses, the pesticide name was too general to be matched with a specific recognized product trade name, in which case, it was sometimes possible to identify the type of pesticide (i.e. insecticide vs. herbicide), but not the active ingredients. The verbatim list also included responses such as "don't recall" or "unknown insecticide", as well as substances other than pesticides such as diesel fuel or fertilizers.
Each verbatim pesticide names was linked with a standard pesticide name, which in turn was linked with up to four PC codes corresponding to the active ingredients listed in the EPA PPIS database or the CPH. When no match with a recognized trade name was possible, then the verbatim name was coded as an unknown pesticide. A preliminary analysis of the pesticide names from the Phase II interviews identified a total of 364 unique active ingredients. Based on frequency of occurrence, active ingredients were identified for 95% of the pesticides applied to crops (324 PC codes), 96% of non-crop pesticides (249 PC codes) and 93% of animal pesticides (86 PC codes). The five most frequently reported pesticide trade names were Round Up, Prowl, Dual, Lorsban and Orthene. The five most common active ingredients based on the frequency of the pesticide trade names were glyphosate, 2,4-D, atrazine, dicamba and malathion.
The standardization of the verbatim pesticide names mentioned by individual applicators can be used to determine which applicators applied pesticides containing one or more specific active ingredients for epidemiologic analyses.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Results from the Ahs Pesticide Exposure Study |
02/26/2004
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Thomas, K. W., S. M. Gordon, M. Jones, J. Raymer, C. Lynch, C. Knott, D. P. Sandler, M. Dosemeci, AND M. Alavanja. Results from the Ahs Pesticide Exposure Study. Presented at AHS National Advisory Panel Meeting, Bethesda, MD, February 26-27, 2004.
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The Agricultural Health Study/Pesticide Exposure Study (AHS/PES) measured exposures resulting from agricultural use of 2,4-D and chlorpyrifos for a subset of applicators in the AHS cohort. Through on-farm measurements and observations, data collected in the exposure study will be used to examine the range of applicator exposures, evaluate AHS exposure classification procedures, identify key exposure factors, and assess whether farm applicator family members are exposed to the applied target pesticides.
A telephone screening process identified private pesticide applicators in the AHS cohort living in selected counties in Iowa and North Carolina that would be eligible for recruitment. Eligibility required the planned use of a target chemical in one of eight different exposure scenarios that were based on combinations of three application methods (broadcast spray, hand spray, banded/in-furrow) and two types of protective equipment (protective gloves and enclosed tractor cabs). Spouses and children living with the applicator were asked to participate. Monitoring was performed around one day of pesticide mixing, loading, and application (MLA). Research staff observed and recorded information about the pesticide MLA activities. Two questionnaires were administered during the monitoring period to collect information on pesticide use, work practices, hygiene, and other activity information. The full AHS Phase II CATI was administered to the exposure study participants several months after the monitoring visit.
One pre-application and two post-application urine samples were collected from participating pesticide applicators. In addition, post-application composite 24-h urine samples were collected from applicators over an additional four days for 48 of the 108 monitored applications. Dermal patch samples were collected by placing 10 cellulose or gauze patches on the applicator's chest, back, upper arms, forearms, upper legs, and lower legs. The surface area of each patch was sized proportionately to the body area it represented. Patches were combined into one or two samples for extraction. Hand wipe samples were collected with isopropanol-wetted polyurethane swabs from 12 defined areas (3-cm2 each) on each hand. Air samples were collected using a small battery-operated pump and an OVS sampling cartridge containing XAD-2 sorbent. Participating spouses and children provided first-morning void urine samples on the day of the observed MLA activity and again two days later. All samples were solvent extracted and analyzed by gas chromatography/mass spectrometry.
A total of 108 monitoring visits were completed at 84 different farms during the planting and growing seasons from 2000 to 2002. Applicators on 20 of those farms were monitored a second time, and four applicators were monitored a third time. Spouses provided urine samples during 49 monitoring visits and child urine samples were collected during 12 visits. An additional nine children participated by completing only the activity questionnaire. There were 84 monitoring visits in Iowa and 24 monitoring visits in North Carolina. Products containing 2,4-D or chlorpyrifos were used 89 and 18 times, respectively, in the monitored applications. One North Carolina applicator used only an atrazine product during the monitoring visit; the dermal and air samples were analyzed for this participant but the urine samples were not. The number of monitored applications in the eight exposure scenario strata ranged from 6 to 22.
All monitored uses of 2,4-D involved liquid product formulations that were applied by broadcast or hand-held sprayers. The 2,4-D concentration in these applicators' pre-application urine samples ranged from <1 to 870 ug/L, while the concentration in the first post-application urine samples ranged from 1.6 to 1000 ug/L. Estimated hand loadings for these applicators at the end of the observed pesticide uses ranged from <10 to 25,000 ug and estimated body loadings ranged from <40 to 880,000 ug. Personal air 2,4-D concentrations ranged from <0.5 to 14 ug/m3. Liquid formulations were used for five of the chlorpyrifos applications while the remaining 13 uses were banded or in-furrow applications of a granular product. The concentration of the chlorpyrifos metabolite 3,5,6-trichloro-2-pyridinol (TCP) in these applicators' pre-application urine samples ranged from 2.1 to 62 ug/L, while the concentration in the first post-application urine samples ranged from 2.5 to 80 ug/L. Estimated hand loadings for these applicators at the end of the observed pesticide uses ranged from <10 to 930 ug and estimated body loadings ranged from <40 to 5800 ug. Personal air chlorpyrifos concentrations ranged from <0.1 to 2.0 ug/m3.
Data review and analysis for this project is ongoing. An overview of the urinary biomarker, dermal, and air concentration measurement results, along with relationships between different measures, will be presented in the meeting poster. Differences in exposure measurements across the eight exposure scenarios will be described to the extent that analyses have been completed. Urinary biomarker measurement results will be presented for the spouses and children.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Use of Agricultural Pesticides and Lung Cancer Risk in the Agricultural Health Study Cohort |
02/20/2004
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Alavanja, M., M. Dosemeci, C. Samanic, J. H. Lubin, C. Lynch, C. Knott, J. Barker, J. A. Hoppin, D. P. Sandler, J. Coble, K. W. Thomas, AND A. Blair. Use of Agricultural Pesticides and Lung Cancer Risk in the Agricultural Health Study Cohort. Presented at AHS National Advisory Panel Meeting, Baltimore, MD, February 26-27, 2004.
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We examined the relationship between 45 common agricultural pesticides and lung cancer incidence in a prospective cohort study of 52,395 private pesticide applicators, 4,916 commercial pesticide applicators and 32,347 spouses of farmer applicators from Iowa and North Carolina with no prior history of lung cancer. Data were collected by means of self-administered questionnaires completed at enrollment (1993-1997). Cancer incidence was determined through population-based cancer registries from enrollment through December 31,2001. A lung cancer standardized incidence ratio (SIR) was computed for the applicator cohort and the spouse cohort separately. Odds Ratios were computed for individual pesticides. A lung cancer SIR, 0.46 (95% CI, 0.40-0.52) and 0.59(95% CI, 0.28-1.09) was observed for the AHS private applicators and commercial applicator cohorts respectively. A lung cancer SIR, 0.36 (95% CI, 0.25-0.53) was observed for spouse of private applicators. This significantly lower risk of lung cancer was due to an extremely low cigarette smoking prevalence in the cohort. Several pesticides showed a significantly increased risk of lung cancer with increasing use of the pesticides and this excess could not be explained by the age of the applicator, cigarette smoking, alcohol consumption, diets low in vegetable consumption, previous non-malignant lung disease, diesel exhaust, educational level, a family history of lung cancer, or state of residence. Non-farm jobs associated with the use of asbestos and lead were also observed to be associated with an increased risk of lung cancer. Age, cigarette smoking, diets low in vegetable consumption, previous non-malignant lung disease, diesel exhaust, not completing high school, or living in the state of North Carolina were all associated with a significant excess risk of lung cancer.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
A PBPK Model of Pyrethroid Pesticides for Application in Risk Assessment |
06/17/2004
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TORNERO-VELEZ, R., C. C. Dary, M. Dellarco, AND J. Blancato. A PBPK Model of Pyrethroid Pesticides for Application in Risk Assessment. Presented at Exposure Assessment in a Changing Environment, Utrecht, The Netherlands, June 16-18, 2004.
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Pyrethroids are among the most potent and effective insecticides available, and are applied singly or in combination in agricultural and indoor insect control. The Food Quality Protection Act (FQPA) of 1996 requires the US EPA to consider the cumulative (multi-chemical) effects of exposure to pesticides having a 'common mechanism of toxicity'. For the risk assessment of pyrethroids, estimation of the extent of exposure and detailed knowledge of their kinetics is of prime importance. Towards this end, we have developed a physiologically-based pharmacokinetic (PBPK) model for evaluating dose resulting from residential and dietary exposures in humans. The application of PBPK models in risk assessment offers key benefits including: prediction of target dose, dose extrapolation in cases of non-linearity, and route of exposure extrapolation. In this project, studies examining the pharmacokinetics of permethrin and deltamethrin in rodents were used to derive the basic model structure. The model included skin, fat, liver, brain, and lumped tissue compartments. Physiological values were obtained from the literature. Tissue-blood partition coefficients were based on Log[Kow] and tissue composition. The model provides a systematic and quantitative framework for considering the impact of aggregate exposure routes (dermal, oral, inhalation). Human urinary excretion studies and computational methods were employed to derive parameters relevant to humans. The low coefficients of dermal permeability (Kp) of these highly lipophillic pesticides (Log[Kow]: 4.5-7) and their low volatility (Vapor Pressure: 10 -11 - 10 -7 mm Hg) suggest that the oral routes (dietary and oral non-dietary) and inhalation (aerosol) have greatest influence on target tissue dose. These preliminary findings will aid in shaping the development of a cumulative risk model of pyrethroids.
The opinions expressed in this manuscript are those of the author and do not reflect opinions or policy of the Environmental Protection Agency. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
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| PRESENTATION |
Supplement to EPA Compendium Method to-15 Reduction of Method Detection Limits to Meet Vapor Intrusion Monitoring Needs |
04/21/2004
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Daughtrey Jr., E. H., K. D. Oliver, H. H. Jacumin Jr., AND W. A. McClenny. Supplement to EPA Compendium Method to-15 Reduction of Method Detection Limits to Meet Vapor Intrusion Monitoring Needs. Presented at Symposium on Air Quality Measurement Methods and Technology, Research Triangle Park, NC, April 20-22, 2004.
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The Supplement to EPA Compendium Method TO-15 provides guidance for reducing the method detection limit (MDL) for the compound 1,1- dichloroethene (1,1-DCE) and for other volatile organic compounds (VOCs) from 0.5 ppbv, as cited in Method TO-15, to much lower concentrations. Revisions to the original wording of Method TO-15 were made where the original language proved limiting to the goal of extending Method TO-15 to low pptv levels or where minor omissions were observed. Also, recommendations in the form of additions were made on aspects of laboratory procedure deemed critical to low-pptv-level analysis. Specifically, the MDL for 1,1 DCE was determined to be 6 pptv. During this effort, a capability for preparing 1,1-DCE sample concentrations of 30 pptv and 60 pptv in ambient air was developed. Using this capability and the capability to prepare samples of humidified zero air, samples were prepared in canisters and sent to three contract laboratories as unknowns. Subsequent comparison of results indicated close agreement among the laboratories while maintaining the performance standards for replicate precision (25%) and audit accuracy (30%) originally specified in Method TO-15. The following compounds were also detected at low levels in canisters filled with spiked ambient air: chloroethene, dichloromethane, cis-1,2-dichloroethene, trichloromethane, 1,2-dichloroethane, benzene, 1,1,1-trichloroethane, trichloroethene , and tetrachloroethene. Since the different laboratories employed different analytical procedures, the use of a performance-based method appears justified.
Although this work was reviewed by EPA and approved for publication, it may not necessaryly reflect official Agency policy. This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
EPA's Supersites Program: Communication Strategy |
02/11/2004
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Solomon, P. A. AND R. Scheffe. EPA's Supersites Program: Communication Strategy. Presented at PM Model Performance Workshop, Research Triangle Park, NC, February 10-11, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Stn/Improve Comparison Study: Preliminary Results |
02/11/2004
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Solomon, P. A., T. KlamserWilliams, P. P. Egeghy, D. Crumpler, AND J. Rice. Stn/Improve Comparison Study: Preliminary Results. Presented at PM Model Performance Workshop, Research Triangle Park, NC, February 10-11, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Stn/Improve Comparison Study Preliminary Results |
01/28/2004
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Solomon, P. A., J. Rice, T. KlamserWilliams, P. P. Egeghy, AND D. Crumpler. Stn/Improve Comparison Study Preliminary Results. Presented at MARAMA/MANE-VU Science Meeting, Baltimore, MD, January 27-29, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Identification of Secondary Organic Aerosol Compounds in Ambient PM2.5 Samples |
02/10/2004
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Edney, E. O. AND T. E. Kleindienst. Identification of Secondary Organic Aerosol Compounds in Ambient PM2.5 Samples. Presented at PM Model Performance Workshop, Chapel Hill, NC, February 10, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Analysis of Selected Pyrethroid Pesticides Using Reverse Phase High Pressure Liquid Chromatography/UV |
03/26/2004
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Morrison, C. N., J. Starr, AND E. M. Ulrich. Analysis of Selected Pyrethroid Pesticides Using Reverse Phase High Pressure Liquid Chromatography/UV. Presented at Society of Environmental Toxicology & Chemistry, Kennesaw, GA, March 25-27, 2004.
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This research was conducted in cooperation with EPA Region 4 in Athens, GA to develop a method to analyze selected pyrethroid pesticides using Reverse Phase-High Pressure Liquid Chromatography (HPLC). This HPLC method will aid researchers in separating and identifying these pyrethroids. The method was developed for Type I pyrethroids without a cyano group (allethrin, permethrin, resmethrin) and Type II pyrethroids with a cyano group (cypermethrin and fenvalerate). The pyrethroids were separated on a Hewlett Packard model 1090 using a Phenomenex C-18 100 x 2.0 mm SYNERGI 4u Hydro-RP 80A column. The flow rate was set at 0.5 mL/min. at 35 degrees C using two mobile phases consisting of acetonitrile-distilled water (1:1, v/v) and methanol-acetonitrile-distilled water (0.5:0.5:1, v/v) with 10 uL injections. The ratios of aqueous to organic mobile phase evaluated ranged from 10:90 to 60:40. Mobile phase conditions of 20% water and 80% acetonitrile separated allethrin (2.207 minutes), resmethrin isomers (7.997, 8.414 minutes), and permethrin isomers (9.631, 11.326 minutes), respectively. Analysis of the pyrethroids separately allows us to hypothesize that, in an unknown sample, complete separation occurs.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy. Mention of trade names of commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Analysis of Selected Pyrethroid Pesticides Using Reverse Phase High Pressure Liquid Chromatography |
03/26/2004
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Morrison, C. N., J. Starr, AND E. M. Ulrich. Analysis of Selected Pyrethroid Pesticides Using Reverse Phase High Pressure Liquid Chromatography. Presented at Society of Toxicology, Kennesaw, GA, March 25-27, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
United States Environmental Protection Agency Research Activities to Characterize Children's Environmental Exposures |
03/22/2004
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CohenHubal, E. A. United States Environmental Protection Agency Research Activities to Characterize Children's Environmental Exposures. Presented at Internantional Symposium on Children's Environmental Health, Tokyo, Japan, March 22, 2004.
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Given the well-established vulnerability of children to the effects of environmental exposures and the array of environmental exposures that have not been studied, understanding the relationship between children's health outcomes and environmental exposures is critical for our children's well being. Over the past eight years significant research activities have been initiated at the United States Environmental Protection Agency (US EPA) to increase understanding of children's vulnerabilities and to better characterize children's exposures to chemical stressors in the environment.
In 1996, the United States Congress enacted two statutes requiring that US EPA consider children when setting health-based standards: the Food Quality Protection Act of 1996 and the Safe Drinking Water Act Amendments of 1996. Subsequently, US EPA expanded its ongoing research in the area through 1998 and 2000 initiatives on children's environmental health. In 2000, US EPA Office of Research and Development (ORD) published its Strategy for Research on Environmental Risks to Children, and in 2002, the Administrator released the US EPA Asthma Research Strategy, which addresses an endpoint of particular concern for children. To support these initiatives and to address the most important research gaps identified in the research strategies, US EPA conducts and funds a variety of research on children's environmental exposure.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official agency policy.
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| PRESENTATION |
The Standardization of Pesticide Names from the Ahs Phase II Questionnaire and the Identification of Their Active Ingredients |
02/26/2004
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Coble, J., Y. Ng, R. Allen, S. Nako, B. Suhre, J. A. Hoppin, K. W. Thomas, C. Hines, AND M. Alavanja. The Standardization of Pesticide Names from the Ahs Phase II Questionnaire and the Identification of Their Active Ingredients. Presented at Agricultural Health Study National Advisory Panel Meeting, Bethesda, MD, February 26-27, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Comprehensive PBPK Modeling Approach Using the Exposure Related Dose Estimating Model (Erdem) |
03/23/2004
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Ruiz, A., A. Tsang, F. W. Power, J. Licitra, J. N. Blancato, C. C. Dary, AND M. V. Evans. Comprehensive PBPK Modeling Approach Using the Exposure Related Dose Estimating Model (Erdem). Presented at Society of Toxicology, Baltimore, MD, March 21-25, 2004.
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ERDEM, a complex PBPK modeling system, is the result of the implementation of a comprehensive PBPK modeling approach. ERDEM provides a scalable and user-friendly environment that enables researchers to focus on data input values rather than writing program code. It efficiently manages these inputs and provides reporting and model output assessment capabilities. This simplifies the modeling efforts for toxicologists, risk assessors, exposure scientists and managers. As PBPK models grow in complexity, the implementation of models, preparation and maintenance of inputs, and the assessment of model output results has become more tedious and error prone.
Concern with the management of these diverse tasks, a comprehensive modeling approach was developed which has been integrated into ERDEM and other PBPK modeling projects. The goal of this modeling approach is to improve the modeling process from planning to application for multimedia exposure assessments. The core activities for this approach include identification and implementation of the model design and performance criteria, metabolism structure and parameterization, the model hardware/software specifications, and the model testing and evaluation.
As a comprehensive modeling system, ERDEM contains a PBPK model engine component that can create scenario-based simulations and target dose estimates in multiple compartments for exposure of a species to multiple chemicals and metabolites. The input management component uses a Windows based graphical user interface and relational database, enabling the user to enter, edit, report, and export data sets of user assigned physiological information. The stochastic component evaluates the uncertainty associated with input parameters and model results. ERDEM replaces the traditional program-oriented modeling approach, which is error prone, with a sophisticated and user-friendly model simulation and data management system.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Overview of Perflourinated Compound Research at the U.S. Environmental Protection Agency's NERL/Mdab |
03/22/2004
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Strynar, M. J. AND A. B. Lindstrom. Overview of Perflourinated Compound Research at the U.S. Environmental Protection Agency's NERL/Mdab. Presented at John Hopkins University Weekly Seminar, Baltimore, MD, March 22, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Overview of Perfluorinated Compound Research at the U.S. Environmental Protection Agency's NERL/Mdab |
11/17/2004
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Lindstrom, A. B. AND M. J. Strynar. Overview of Perfluorinated Compound Research at the U.S. Environmental Protection Agency's NERL/Mdab. Presented at Kyoto University Graduate School of Medicine, Department of Health and Environmental Sciences, Kyoto, Japan, November 17, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Exposure Assessment Findings from the Tampa Asthmatic Children's Study (Tacs) |
10/19/2004
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Williams, R. W., C. Stevens, K. W. Leovic, F. L. Chen, A. F. Vette, R. L. Seila, W. E. Amos, L. S. Sheldon, C. Rodes, J. Thornburg, AND C. Croghan. Exposure Assessment Findings from the Tampa Asthmatic Children's Study (Tacs). Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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The Tampa Asthmatic Children's Study (TACS) was a pilot study that focused on developing and evaluating air pollution exposure assessment methods and participant recruiting tools. The four-week study was performed in October and November, 2003. The study involved repeated daily personal, residential, and ambient air pollution measurements for a cohort of nine children. Measurements were taken to determine the microenvironmental concentrations of combustion-related products (CRP), particulate matter (PM), and some air toxics. A portable "lunch box" was developed that permitted air in close proximity to the young child (personal) to be continuously monitored. The lunch box was designed to fully contain all of the active and passive sampling devices needed for personal monitoring of each child in a safe and effective manner. The lunch box had to be lightweight, quiet, and portable so that it would be easy to move the box and keep it near their child at all times. Participating children were clinically diagnosed as being asthmatics, +/- 5 years of age, and lived in single family dwellings with nonsmoking parents. They were recruited through a broad-based campaign consisting of public notices, physician and community contacts. The study involved 24-hour integrated PM2.5 and PM10 mass measurements over four consecutive days for each participant. Real-time measurement of PM2.5 mass concentrations were collected using the MIE-pDR nephelometer. These measures and the activities recorded in a daily dairy will be used to correlate the child's personal PM exposure with their activities and the microenvironments where they spend time. Concentrations of a number of criteria pollutants (CO, SO2, NO2, O3) were also measured. Data collection for the study has been completed and an initial data analysis has been performed. Mean daily personal, residential indoor, residential outdoor, and ambient PM2.5 mass concentrations were 12.5, 9.3, 11.3, and 12.7 ug/m3, respectively. Personal PM2.5 mass concentrations ranged from 6.1 to 26.1ug/m3. Specific source events such as exposure to cooking aerosols, household cleaning events, and riding in an automobile were determined to contribute to the children's total personal PM exposure. Personal and residential indoor concentrations of criteria pollutants were determined to below the national ambient air quality standards for all participants.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by the EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Sampling and Analysis of Semivolatile Aerosols |
04/06/2004
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Volckens, J. Sampling and Analysis of Semivolatile Aerosols. Presented at State of the Science Workshop on Organic Speciation in Atmospheric Aerosols, Las Vegas, NV, April 5-7, 2004.
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Denuder based samplers can effectively separate semivolatile gases from particles and 'freeze' the partitioning in time. Conversely, samples collected on filters partition mass according to the conditions of the influent airstream, which may change over time. As a result these time-integrated sampling techniques do not measure 'average Kp,' but instead report Kp measurements that are weighted towards the end of the sampling event. Several examples of such bias will be presented and discussed. However, denuders are subject to the same types of biases that affect filters and care must be taken in their use. Furthermore, the ratio Kp is easily corrupted by even minute artifacts that affect filters and denuders alike. Some of these errors are easily detected from plots of log Kp vs. log compound vapor pressure, P0 while others are more difficult to identify. Estimates of Kp can vary by up to two orders of magnitude depending on the sampling method used. A need exists to develop an improved sampling technique with less perturbation of semi-volatile equilibrium, shorter sampling periods, and lower limits of detection.
Although this work was reviewed by EPA and approved for presentation, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Multi-Site Evaluations of Candidate Methodologies for Determining Coarse Particulate Matter (Pmc) Concentrations |
04/15/2004
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Vanderpool, R., T. G. Ellestad, M. K. Harmon, T. Hanley, R. Scheffe, E. Hunike, P. A. Solomon, R. Murdoch, S. Natarajan, C. A. Noble, J. Ambs, G. Sem, AND J. Tisch. Multi-Site Evaluations of Candidate Methodologies for Determining Coarse Particulate Matter (Pmc) Concentrations. Presented at Managing Environmental Quality Systems, Tampa, FL, April 15, 2004.
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Comprehensive field studies were conducted to evaluate the performance of sampling methods for measuring the coarse fraction of PM10 in ambient air. Five separate sampling approaches were evaluated at each of three sampling sites. As the primary basis of comparison, a discrete difference method was used which employs two designated FRM samplers, one to measure PM2.5 and the other PM10. The numerical difference of these reference method concentrations (PM10-PM2.5) represented an estimate of PMc. A second sampling approach involved a sequential dichotomous sampler, which provided both PM2.5 and PMc measurements. In both of these filter-based, time-integrated measurement approaches, the collected aerosol mass was analyzed gravimetrically in the laboratory under controlled temperature and relative humidity conditions. Three continuous coarse particle samplers that measure PMc directly with a time resolution of 1 hour or less were also evaluated. One such sampler was a commercially available system based on beta attenuation, the second was based on TEOM technology. Both of these measurement approaches used dichotomous virtual impactors for separating fine and coarse particles. The third real-time sampler evaluated was an aerodynamic particle sizer (APS) that measures the aerodynamic diameter of individual particles, calculates the mass of the particle based on an assumed particle density, then sums the mass within the size range of interest to estimate the PMc mass concentration.
Sampling sites and timing of the studies were selected to provide diverse challenges to the samplers with respect to aerosol concentration, aerosol particle size distribution, and aerosol composition. Results from performance evaluations of the candidate PMc samplers at Gary, IN, Phoenix, AZ, and Riverside, CA are summarized.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Multi-Site Evaluations of Candidate Methodologies for Determining Coarse Particulate Matter (Pmc) Concentrations |
04/21/2004
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Vanderpool, R., T. G. Ellestad, M. K. Harmon, T. Hanley, R. Scheffe, E. Hunike, P. A. Solomon, R. Murdoch, S. Natarajan, C. A. Noble, J. Ambs, G. Sem, AND J. Tisch. Multi-Site Evaluations of Candidate Methodologies for Determining Coarse Particulate Matter (Pmc) Concentrations. Presented at Symposium of Air Quality Measurement Methods and Technology, Research Triangle Park, NC, April 20-22, 2004.
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Comprehensive field studies were conducted to evaluate the performance of sampling methods for measuring the coarse fraction of PM10 in ambient air. Five separate sampling approaches were evaluated at each of three sampling sites. As the primary basis of comparison, a discrete difference method was used which employs two designated FRM samplers, one to measure PM2.5 and the other PM10. The numerical difference of these reference method concentrations (PM10-PM2.5) represented an estimate of PMc. A second sampling approach involved a sequential dichotomous sampler, which provided both PM2.5 and PMc measurements. In both of these filter-based, time-integrated measurement approaches, the collected aerosol mass was analyzed gravimetrically in the laboratory under controlled conditions. Three continuous coarse particle samplers that measure PMc directly with a time resolution of 1 hour or less were also evaluated. One such sampler was a commercially available system based on beta attenuation, the second was based on TEOM technology. Both of these measurement approaches used dichotomous virtual impactors for separating fine and coarse particles. The third real-time sampler evaluated was an aerodynamic particle sizer (APS) that measures the aerodynamic diameter of individual particles, calculates the mass of the particle based on an assumed particle density, then sums the mass within the size range of interest to estimate the PMc mass concentration.
Sampling sites and timing of the studies were selected to provide diverse challenges to the samplers with respect to aerosol concentration, aerosol particle size distribution, and aerosol composition. Results from performance evaluations of the candidate PMc samplers at Gary, IN, Phoenix, AZ, and Riverside, CA will be presented.
This paper has been reviewed in accordance with the United States Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation by the Agency.
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| PRESENTATION |
The Monitoring and Modeling of Mercury Species in Support of Local, Regional, and Global Modeling |
05/24/2004
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Landis, M. S. AND R. K. STEVENS. The Monitoring and Modeling of Mercury Species in Support of Local, Regional, and Global Modeling. Presented at Harmonization of Mercury Measurement Methods and Models, Maratea, Italy, May 23-26, 2004.
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Cyrill Brosset, as early as 1979, recognized through research on the chemical forms of mercury in rain and in the air in Sweden and the Baltic States that (i) coal fired utility boilers in Eastern Europe were sources of mercury contaminating lakes in Sweden, and (ii) that both elemental and mercury halides (e.g., HgCl2) were being transported to these sites. His methods of measuring the various forms of mercury, were at the time extremely innovative, but required at least 24 hour sampling and subsequent complex laboratory analysis. Brosset recognized at that time a need to speiciate the forms of mercury being emitted from power plants and incinerators and the importance of developing near real time atmospheric mercury measurements.
It was not until the late 1990's that reliable techniques for speciation of mercury emissions and ambient air became available. Subsequent field studies confirmed Brosset's earlier work that, indeed, fossil fueled combustion sources emit both elemental and divalent forms of mercury, referred to as reactive gaseous mercury (RGM). RGM in stack emissions is most likely in the form of mercuric chloride (HgCl2). Atmospheric mercury studies in the Florida Everglades and Great Lakes during the 1990's demonstrated the relative importance of RGM dry deposition as a significant contributor of total mercury loading to these aquatic ecosystems. More recent studies including aircraft measurements off the coast of Florida (60-3500 m), at the Mauna Loa high altitude research station (3500 m), and in the Polar regions have shown elemental mercury is oxidized into RGM and particulate phase mercury via halide/photochemical reactions.
Since a significant portion of the atmospheric chemistry of mercury is poorly understood, contemporary atmospheric mercury models do not adequately simulate halide oxidation mechanisms observed in during polar mercury depletion events or in the marine free troposphere. This reality coupled to a lack of a comprehensive global emissions inventory that includes speciated anthropogenic and natural mercury sources limit the present reliability of deterministic models in predicting atmospheric behavior and deposition of mercury over short temporal and large spatial scales. To investigate the transport and deposition of atmospheric mercury and to elucidate the local, regional and global impact of industrial emissions, appropriate source and receptor site chemical monitoring and characterization is required.
The purpose of this paper is to provide information on contemporary mercury speciation and associated air quality monitoring methodologies required to generate the data necessary to conduct a robust source apportionment/receptor modeling study.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Picture Perfect: in Depth Look at the Picture Format |
11/01/2004
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Croghan, C. Picture Perfect: in Depth Look at the Picture Format. Presented at SouthEast SAS Users Group, Nashville, TN, October 31-November 2, 2004.
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SAS picture format is a very powerful tool. The different options allow the display of data in a more picturesque manner adding symbols, qualifiers, and comments to the data points without modifying the data. With a picture format one can create a series of templates for displaying the data. The picture format even allows the user to generate their own date and time formats. In addition to the options available with the value formats, picture format has options such as datatype, noedit, prefix, multiplier, and fill. With its multitude of options, the picture format is very powerful, but it can also be confusing. It is not always clear how different options will interact. The width of the format will affect the results. Picture formats will truncate the data that does not fit into the template width. If not careful, this can produce misleading information. This presentation will look at the structure and the options available removing some of the mystery of the picture format removed and revealing a powerful formatting.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Picture Perfect: in Depth Look at the Picture Format |
11/01/2004
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Croghan, C. Picture Perfect: in Depth Look at the Picture Format. Presented at SouthEast SAS Users Group, Nashville, TN, October 31-November 2, 2004.
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SAS PICTURE format is a very powerful tool. The different options allow the display of data in a more picturesque manner adding symbols, qualifiers, and comments to the data points without modifying the data. With a PICTURE format one can create a series of templates for displaying the data. The PICTURE format even allows the user to generate their own date and time formats. In addition to the options available with the VALUE formats, PICTURE format has options such as DATATYPE, NOEDIT, PREFIX, MULTIPLIER, and FILL. With its multitude of options, the PICTURE format is very impressive, but it can also be confusing. It is not always clear how different options will interact. If not carefully applied, the PICTURE format can produce misleading information. This presentation will look at the structure and the options available, removing some of the mystery of the PICTURE format and revealing a powerful formatting tool.
This paper has been reviewed in accordance with the United States Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation by EPA for use.
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| PRESENTATION |
Picture Perfect: Indepth Look at the Picture Format |
11/01/2004
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Croghan, C. Picture Perfect: Indepth Look at the Picture Format. Presented at SouthEast SAS Users Group, Nashville, TN, October 31- November 2, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
A Probabilistic Exposure Assessment for Children Who Contact Cca-Treated Playsets and Decks Using the Stochastic Human Exposure and Dose Simulation (Sheds) Model for the Wood Preservative Exposure Scenario |
10/20/2004
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Zartarian, V., J. Xue, A. H. Ozkaynak, W. Dang, G. Glenn, L. Smith, AND C. Stallings. A Probabilistic Exposure Assessment for Children Who Contact Cca-Treated Playsets and Decks Using the Stochastic Human Exposure and Dose Simulation (Sheds) Model for the Wood Preservative Exposure Scenario. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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The U.S. Environmental Protection Agency has conducted a probabilistic exposure and dose assessment on the arsenic (As) and chromium (Cr) components of Chromated Copper Arsenate (CCA) using the Stochastic Human Exposure and Dose Simulation model for wood preservatives (SHEDS-Wood). A draft assessment was presented to OPP's Scientific Advisory Panel in December, 2003 and is currently being finalized. This assessment is part of the Agency's health risk assessment for children who frequently contact CCA-treated wood in playsets and home decks and CCA-contaminated soil around these structures. Two bounding estimate climate scenarios; three exposure time periods (short-term, intermediate-term, and lifetime); and four pathways (dermal contact with, and ingestion of, As and Cr in both soil and wood residues) were considered. Variability, sensitivity, and uncertainty analyses were conducted, as well as special analyses considering different subpopulations (e.g., pica children) and exposure reduction scenarios (e.g., sealants, hand washing). The draft assessment was presented to OPP's Scientific Advisory Panel in December, 2003 and is currently being finalized. The results from this probabilistic exposure and dose analysis showed that the predicted central values for lifetime annual average daily dose values for arsenic were on the order of 10-6 to 10-5 mg/kg/day, with the predicted 95th percentiles on the order of 10-5 mg/kg/day. There was several orders of magnitude difference between the lower and the upper percentiles of predicted population exposure and dose variability estimates. Residue ingestion via hand-to-mouth contact was the most significant exposure route for most scenarios. The key variables that were found to influence model estimates were: wood surface residue-to-skin transfer efficiency, wood surface residue concentrations, fraction of hand surface area mouthed, hand washing events, soil concentrations near treated playsets, daily soil ingestion rate, and time spent on/around treated residential decks. Alternative scenarios did not significantly impact the baseline results, except for the impact of greatly reducing wood residues through hypothetical wood sealant applications. Finally, the SHEDS-Wood CCA probabilistic results were found to compare well to results from other deterministic CCA exposure assessments.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Application and Evaluation of An Aggregate Physically-Based Two-Stage Monte Carlo Probabilistic Model for Quantifying Children's Residential Exposure and Dose to Chlorpyrifos |
10/20/2004
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Xue, J., V. Zartarian, A. H. Ozkaynak, S. V. Liu, G. Glenn, AND L. Smith. Application and Evaluation of An Aggregate Physically-Based Two-Stage Monte Carlo Probabilistic Model for Quantifying Children's Residential Exposure and Dose to Chlorpyrifos. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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Critical voids in exposure data and models lead risk assessors to rely on conservative assumptions. Risk assessors and managers need improved tools beyond the screening level analysis to address aggregate exposures to pesticides as required by the Food Quality Protection Act of 1996. Thus, there is a need for developing probabilistic aggregate and cumulative source-to-dose models for assessing realistic multimedia, multipathway exposure and risk to pollutants and populations of concern. The aggregate Stochastic Human Exposure and Dose Simulation model for multimedia, multipathway pollutants (SHEDS-Pesticides) is a physically-based probabilistic model designed to estimate likely values of human exposure and dose to selected multimedia/multipathway pollutants. SHEDS-Pesticides combines actual human activity data (from national time/activity diary surveys and videography studies) with residue and concentration measurements in media contacted, exposure factors, and dose factors. The model then predicts, for user-specified cohorts, exposures and doses incurred via eating contaminated foods or drinking water, inhaling contaminated air, touching contaminated surface residues, and ingesting residues from hand- or object- to-mouth activities. To illustrate model capabilities, an aggregate case study for young children and chlorpyrifos was conducted, and model predictions were evaluated using measured chlorpyrifos data from the National Human Exposure Assessment Survey (NHEXAS) Minnesota Children's study. Three post-application time periods (<1,1-7, 8-30 days) were considered for indoor residential crack and crevice applications and outdoor liquid and granular turf applications. Non-dietary ingestion and dermal contact were found to be the most important routes for shorter post-application time periods (<7 days); inhalation and dietary ingestion were most important for longer time periods (>7 days). Despite current data limitations and model assumptions, the model predictions of exposure and dose compared well with the Minnesota Children's data, and provided useful insights to the relative importance of exposure routes and critical model inputs.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Application and Evaluation of An Aggregate Physically-Based Monte Carlo Probabilistic Model of Quantifying Children's Residential Exposure and Dose to Chlorpyrifos |
10/19/2004
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Xue, J., V. Zartarian, A. H. Ozkaynak, S. V. Liu, G. Glenn, AND L. Smith. Application and Evaluation of An Aggregate Physically-Based Monte Carlo Probabilistic Model of Quantifying Children's Residential Exposure and Dose to Chlorpyrifos. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Levels of Organophosphates and Their Degradation Products in the Homes, Day Care Centers, and Urine of 127 Ohio Preschool Children |
10/19/2004
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Morgan, M. K., L. S. Sheldon, C. Croghan, P. A. JONES, N. K. Wilson, J. C. Chuang, AND C. Lyu. Levels of Organophosphates and Their Degradation Products in the Homes, Day Care Centers, and Urine of 127 Ohio Preschool Children. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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This study examined the aggregate exposures of 257 preschool children to pollutants commonly found in their everyday environments. A primary objective of the study was to identify important sources and routes that contribute to the children's exposures in these environments. Participants were recruited randomly from selected homes and day care centers in 12 North Carolina and Ohio counties. Monitoring was performed over a 48-h period at the children's homes and/or day care centers. Samples that were collected included diet, water, air, urine, dust, soil, and surface wipes. The samples were analyzed by gas chromatography/mass spectrometry for over 50 pollutants including chlorpyrifos and diazinon as well as their degradation products 3,5,6-trichloro-2-pyridinol (TCP) and 2-isopropyl-6-methyl-4-pyrimidinol (IMP). We have reported the preliminary results for the levels of these two organophosphates and their degradation products in multimedia samples collected at the homes (n=127) or day cares (n=16) of 127 Ohio preschool children. The median levels of chlorpyrifos and TCP measured at homes were 52.0 and 41.0 ng/g (dust), 1.7 and 0.6 ng/m3 (indoor air), and 0.2 and 1.9 ng/g (solid food), respectively. At day cares, the median levels of chlorpyrifos and TCP were 174.0 and 57.7 ng/g (dust), 2.1 and 0.7 ng/m3 (indoor air), and 0.1 and 1.5 ng/g (solid food). The median levels of diazinon and IMP at homes were 19.8 and 14.3 ng/g (dust), 1.0 and 0.5 ng/m3 (indoor air), and <0.1 and 0.4 ng/g (solid food), respectively. At day cares, the median levels of diazinon and IMP were 40.0 and 16.7 ng/g (dust), 1.0 and 0.5 ng/m3 (indoor air), and <0.1 and 0.4 ng/g (solid food), respectively. The median TCP concentration in the children's urine was 5.1 ng/mL. The results suggested that pesticides and their metabolites should be simultaneously measured in media, particularly when using these metabolites as urinary biomarkers of exposure.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Comparison of Measurement of Ambient Particle Nitrate With Semi-Continuopus Instruments |
04/21/2004
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Long, R. W. AND W. A. McClenny. Comparison of Measurement of Ambient Particle Nitrate With Semi-Continuopus Instruments. Presented at Symposium on Air Quality Measurement Methods and Technology, Research Triangle Park, NC, April 20-22, 2004.
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Comparisons between two different semi-continuos monitors of ambient level particulate nitrate are interpreted for both field and laboratory studies. One instrument involves flash vaporization of impacted particulate nitrate to form a combination of NO and NO2 gases which are detected as NO in a chemiluminescence monitor. The second instrument involves the collection of particulate nitrate in a mist chamber with subsequent analysis of nitrate ions by ion chromatography (IC). Ambient measurements in Rubidoux, CA during July 2003 as well as measurements in the EPA research laboratories at Research Triangle Park, NC suggest the occurrence of decreased instrumental response related to particle bound water (or other matrix) content for the monitor using flash vaporization. Both Ambient and laboratory experimental results are interpreted.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Supplement to EPA Compendium Method to-15 Reduction of Method Detection Limits to Meet Vapor Intrusion Monitoring Needs |
04/20/2004
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Daughtrey Jr., E. H., K. D. Oliver, H. H. Jacumin Jr., AND W. A. McClenny. Supplement to EPA Compendium Method to-15 Reduction of Method Detection Limits to Meet Vapor Intrusion Monitoring Needs. Presented at Symposium on Air Quality Measurement Methods and Technology, Research Triangle Park, NC, April 20-22, 2004.
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The Supplement to EPA Compendium Method TO-15 provides guidance for reducing the method detection limit (MDL) for the compound 1,1-dichloroethene (1,1-DCE) and for other volatile organic compounds (VOCs) from 0.5 parts per billion by volume (ppbv), as cited in Method TO-15, to much lower concentrations. Revisions were made to the wording of Method TO-15 where the original language proved limiting to the goal of extending Method TO-15 to low parts per trillion by volume (pptv) levels or where minor omissions were observed. Also, recommendations in the form of additions were made on aspects of laboratory procedure deemed critical to low-pptv-level analysis. Specifically, the MDL for 1,1-DCE was determined to be 6 pptv. During this effort, a capability for preparing 1,1-DCE sample concentrations of 30 pptv and 60 pptv in ambient air was developed. Using this capability and the capability to prepare samples of humidified zero air, samples were prepared in canisters and sent to three contract laboratories as unknowns. Subsequent comparison of results indicated close agreement among the laboratories while maintaining the performance standards for replicate precision (25%) and audit accuracy (30%) originally specified in Method TO-15. The following compounds were also detected at low pptv levels in canisters filled with spiked ambient air: chloroethene, dichloromethane, cis-1,2-dichloroethene, trichloromethane, 1,2-dichloroethane, benzene, 1,1,1-trichloroethane, trichloroethene, and tetrachloroethene. Since the different laboratories employed different analytical procedures, the use of a performance-based method appears justified.
This work has been partially funded by the United States Environmental Protection Agency under Contract 68-D-00-206 to ManTech Environmental Technology, Inc. This paper has been reviewed in accordance with the Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
24-Hour Diffusive Sampling of 1,3-Butadiene in Air Onto Carbopack X Solid Adsorbent Followed By Thermal Desorption/Gc/MS Analysis Feasibility Study |
04/21/2004
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McClenny, W. A., D. A. Whitaker, K. D. Oliver, H. H. Jacumin Jr., AND E. H. Daughtrey Jr. 24-Hour Diffusive Sampling of 1,3-Butadiene in Air Onto Carbopack X Solid Adsorbent Followed By Thermal Desorption/Gc/MS Analysis Feasibility Study. Presented at Symposium on Air Quality Measurement Methods and Technology, Research Triangle Park, NC, April 20-22, 2004.
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Diffusive sampling of 1,3-butadiene for 24 hr onto the graphitic adsorbent Carbopack X packed in a stainless steel tube badge (6.3 mm o.d., 5 mm i.d., and 90 mm in length) with analysis by thermal desorption/gas chromatography (GC)/mass spectrometry (MS) has been evaluated in controlled tests. A test matrix of 42 trace-level volatile organic compounds (VOCs) in humidified zero air was established by dynamic dilution of compressed gas standards flowing through an environmental chamber. Conditions for both automated thermal desorption of the badge, including pre-desorption dry purging, and GC/MS analyses (column flow rate and temperature programming profile) were optimized for specificity, precision, and sensitivity of response. Analytical system responses for sets of tubes exposed to a given 1,3-butadiene concentration were typically precise, e.g., a % RSD < 10% at 1.1 ug/m3 (0.5 ppbv), and system response was approximately linear with concentration over the range 0-9 ug/m3. No significant systematic variations of response were observed for changes in sample humidity and temperature (35% and 75% RH at 16, 20, and 29 "C). Loss of 1,3-butadiene from the tube badge due to reverse diffusion into clean air over 12 hr after an initial 12-hr exposure at 9 ug/m3 gave an 11% response decrease. Adding 100 ppbv (~ 200 ug/m3) of ozone during the second 12 hr caused no additional response change.
This work has been partially funded by the United States Environmental Protection Agency under Contract 68-D-00-206 to ManTech Environmental Technology, Inc. This paper has been reviewed in accordance with the Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Evaluation and Use of Stand-Alone Commercial Photolytic Converters for Conversion of NO2 and No |
04/21/2004
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Kronmiller, K. G. AND W. A. McClenny. Evaluation and Use of Stand-Alone Commercial Photolytic Converters for Conversion of NO2 and No. Presented at Symposium on Air Quality Measurement Methods and Technology, Research Triangle Park, NC, April 20-22, 2004.
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Two types of stand-alone photolytic converters of nitrogen dioxide (NO2) to nitric oxide (NO) are now commercially available for use with NO, ozone (O3) chemiluminescence detector (CLD) monitors for the measurement of NO2. Both units have been tested for interferences resulting from photolysis of nitrous acid (HONO) and from the decomposition of peroxyl acetyl nitrate (PAN). One unit (Model 81800, Spectra-Physics Stratford, CT) is based on the use of a broadband source (short-arc mercury lamp) and incorporates a source cooler. This unit has been used for two month-long field studies, one in May 2002 and a second in October 2003. The results indicate that the converter is robust and reliable with conversion efficiencies (CEs) of 35-70% depending on the airflow rate through the converter. The second commercial unit (Droplet Measurement Technologies-Sonoma Technology, Inc., Petaluma, CA) is based on a light-emitting diode (LED) array with output emission wavelengths centered near 390 nm with emission bandwidths of typically 20 nm. This unit is being field tested for use as part of ongoing tests. Based on results so far, the prospect of using one of the stand-alone converters with an external, heated metal (molybdenum) converter and a chemiluminescence monitor to measure NO, NO2, and NOY (e.g., NO, NO2, HNO3, HONO, HO2NO2, NO3, N2O5, and organic nitrate) seems reasonable.
This work has been partially funded by the United States Environmental Protection Agency under Contract 68-D-00-206 to ManTech Environmental Technology, Inc. This paper has been reviewed in accordance with the Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use
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| PRESENTATION |
Assessing Children's Exposures to the Wood Preservative Cca (Chromated Copper Arsenate) on Treated Playsets and Decks |
06/02/2004
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Zartarian, V., J. Xue, AND A. H. Ozkaynak. Assessing Children's Exposures to the Wood Preservative Cca (Chromated Copper Arsenate) on Treated Playsets and Decks. Presented at EPA Science Forum 2004, Washington, DC, June 1-3, 2004.
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Concerns have been raised regarding the safety of young children contacting arsenic and chromium residues while playing on and around Chromated Copper Arsenate (CCA) treated wood playground structures and decks. Although CCA registrants voluntarily canceled treated wood for residential use effective December 31, 2003, the potential for exposure from existing treated wood structures and surrounding soil still poses child health hazard concerns.
The EPA's Office of Research and Development (ORD), National Exposure Research Laboratory (NERL) collaborated closely with the EPA's Office of Prevention, Pesticides, and Toxic Substances (OPPTS), Office of Pesticide Programs (OPP) to conduct a probabilistic exposure assessment for children in the United States who frequently contact treated wood playsets and decks in public and residential locations. NERL's probabilistic Stochastic Human Exposure and Dose Simulation model for wood preservatives (SHEDS-Wood) was developed and applied to estimate children's absorbed dose of the arsenic and hexavalent chromium components of CCA. ORD's exposure assessment was used by OPP to help determine the potential short-term, intermediate-term, and lifetime cancer risks for the population of interest.
Skin contact with, and ingestion of, arsenic and chromium in soil and wood residues were considered for a population of children simulated by SHEDS-Wood using EPA's Consolidated Human Activity Database (CHAD). Model analyses were conducted to assess the range and uncertainty in population estimates, key model inputs, and the impact of various potential mitigation strategies such as the use of sealants and hand washing after play events. Draft reports for the exposure and risk assessments can be found on the EPA website for the December 3-5, 2003 Scientific Advisory Panel meeting: www.epa.gov/scipoly/sap.
OPP's Reregistration Eligibility Decision (RED) document for Chromated Arsenicals will include a comprehensive assessment of the potential impacts of CCA on human health and the environment. It is anticipated that the outcome of OPP/ORD human health risk assessment will be pivotal in the risk management and reregistration eligibility decisions for CCA, and in advising the public how to minimize health risks from existing treated wood structures
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Harmonization and Communication of PBPK Models Using the Exposure Related Dose Model (Erdem) System: Trichloroethylene |
06/02/2004
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Okino, M. S., F. W. Power, J. N. Blancato, W. Chiu, C. Chen, AND J. Lipscomb. Harmonization and Communication of PBPK Models Using the Exposure Related Dose Model (Erdem) System: Trichloroethylene. Presented at EPA Science Forum 2004, Washington, DC, June 1-3, 2004.
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In support of the trichloroethylene (TCE) risk assessment for the Office of Air and Radiation, Office of Solid Waste and Emergency Response, and Office of Water, NERL and NCEA are developing an updated physiologically-based pharmacokinetic (PBPK) model. The PBPK modeling effort is in conjunction with a workgroup organized by TERA (Toxicology Excellence for Risk Assessment) that includes researchers from academia, the Air Force, and outside industry. PBPK models are powerful computational tools that can be used to link exposure to the internal concentrations of parent compounds and/or active metabolites at the target site(s) of toxicity. Challenges in model development are the comparison and harmonization of existing models, management of multiple diverse datasets, and characterization of the uncertainties. The implementation and documentation of a mathematical model in a general structure addresses these issues by managing the chemicals, compartments, and parameters in a consistent manner. The Exposure Related Dose Estimating Model (ERDEM) platform, developed by NERL, provides an appropriate structure. Also, the EPA Science Advisory Board has stressed the importance of transparency in the updated assessment of TCE. The development of the updated PBPK model in the ERDEM system addresses this charge through its graphical user interface (GUI), standard report generation, and availability to the public. Evaluation of the model can be done at a high level - standard reports or simulations of new scenarios through the GUI - and at varying levels of detail down to the actual FORTRAN code. This enables use and review by researchers of diverse backgrounds.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Harmonization and Communication of PBPK Models Using the Exposure Related Dose Estimation Model (Erdem) System: Trichloroethylene |
06/02/2004
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Okino, M. S., F. W. Power, J. Blancato, W. Chiu, C. W. Chen, AND J. Lipscomb. Harmonization and Communication of PBPK Models Using the Exposure Related Dose Estimation Model (Erdem) System: Trichloroethylene. Presented at EPA Science Forum 2004, Washington, DC, June 1-3, 2004.
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| Abstract:
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In support of the trichloroethylene (TCE) risk assessment for the Office of Air and Radiation, Office of Solid Waste and Emergency Response, and Office of Water, NERL and NCEA are developing an updated physiologically-based pharmacokinetic (PBPK) model. The PBPK modeling effort is being coordinated with a workgroup co-sponsored by EPA and the U.S. Air Force and facilitated by Toxicology Excellence for Risk Assessment (TERA). The workgroup includes researchers from EPA, academia, the Air Force, and private consulting. PBPK models are powerful computational tools that can be used to link exposure to the internal concentrations of parent compounds and/or active metabolites at the target site(s) of toxicity. Challenges in model development are the comparison and harmonization of existing models, management of multiple diverse datasets, and characterization of the uncertainties. The implementation and documentation of a mathematical model in a general structure addresses these issues by managing the chemicals, compartments, and parameters in a consistent manner. The Exposure Related Dose Estimating Model (ERDEM) platform, developed by NERL, provides an appropriate structure. The EPA Science Advisory Board has stressed the importance of transparency in the updated assessment of TCE. The development of the updated PBPK model in the ERDEM system addresses this charge through its graphical user interface (GUI), standard report generation, and availability to the public. Evaluation of the model can be done at a high level - standard reports or simulations of new scenarios through the GUI - and at varying levels of detail down to the actual FORTRAN code. This enables use and review by researchers of diverse backgrounds.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Laboratory and Field Evaluation of Instrumentation for the Semi-Continuous Determination of Particulate Nitrate (and Other Water-Soluble Particulate Compounds) |
06/23/2004
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Long, R. W. AND W. A. McClenny. Laboratory and Field Evaluation of Instrumentation for the Semi-Continuous Determination of Particulate Nitrate (and Other Water-Soluble Particulate Compounds). Presented at A&WMA 's 97th Annual Conference & Exhibition, Indianapolis, IN, June 22-25, 2004.
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Studies conducted at the EPA facility in Research Triangle Park, NC and at a field study in Southern California have demonstrated the capability for the semi-continuous determination of particulate nitrate (and other water soluble ionic species). Two instruments, a R&P 8400N particulate nitrate monitor and an ion chromatography (IC)-based prototype monitor developed at Texas Tech University (TTU), were evaluated both in the laboratory using a simulated ambient aerosol and in the field (Rubidoux, CA) during a three week joint ambient comparison study with Brigham Young University (BYU) and the South Coast Air Quality Monitoring District (SCAQMD). During the initial laboratory studies, both instruments were responsive to changes in the simulated aerosol concentration. However, potential problems were discovered involving both instruments during the laboratory based studies and these problems are currently being addressed. Both instruments were then transported to the SCAQMD Rubidoux field site and operated for a period of three weeks (July 1- 21, 2003). Due to manufacturer's quality assurance issues associated with IC components of the TTU prototype instrument, limited data were obtained from this instrument during the three week sampling period. Initial comparisons show general agreement between the R&P and IC-based prototype instruments for the semi-continuous determination of ambient particulate nitrate at lower nitrate concentrations (<15 ug/m3) and an under determination by the R&P instrument at higher concentrations (>15 ug/m3). During the three week study period, 15-minute average particulate nitrate concentrations approaching 30 ug/m3 were observed. Semi-continuous results obtained from the EPA-operated instruments were averaged and compared to integrated sampler results obtained by BYU and SCAQMD. Results of the laboratory and field studies will be addressed.
This paper has been reviewed in accordance with the United States Environmental Protection Agency's peer and administrative policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Contribution of Fine Particles of Outdoor Origin to Personal Exposures: Results of a 37-Person Panel Study in North Carolina |
10/19/2004
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Wallace, L. A. AND R. W. Williams. Contribution of Fine Particles of Outdoor Origin to Personal Exposures: Results of a 37-Person Panel Study in North Carolina. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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The US EPA carried out a study of personal exposures to PM2.5 for 37 persons with hypertension or cardiovascular disease in North Carolina. Personal, indoor (home) and outdoor (home and central site) 24-h samples were collected for 7 consecutive days in each of four seasons in 2000-2001. PM results from the study have been previously reported (Williams et al., 2003a,b). We have applied a method based on sulfur measurements to calculate the portion of indoor PM2.5 concentrations and personal exposure due to outdoor particles. Because sulfur has few sources indoors, it can be used as a marker for PM of outdoor origin. All filters (>2000 from the personal, indoor at home and outdoor near home samples) were analyzed by X-ray fluorescence for sulfur among other elements. The fraction of personal exposure due to outdoor particles measured near the homes ranged from 0.33 to 0.77, with a median of 0.53. R2 values for regressions of the outdoor-generated contribution to personal PM2.5 exposure vs. outdoor measurements at the central site ranged from 0.19 to 0.88, with a median value of 0.73.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Coarse PM Methods Evaluation Study Study Design and Results |
04/15/2004
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Vanderpool, R., T. G. Ellestad, P. A. Solomon, M. K. Harmon, S. Natarajan, C. A. Noble, R. Murdoch, J. Ambs, J. Tisch, AND G. Sem. Coarse PM Methods Evaluation Study Study Design and Results. Presented at EPA Region 8 Air Monitoring Meeting, Denver, CO, April 14-15, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Coarse PM Methods Evaluation Study: Study Design and Results |
05/12/2004
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Vanderpool, R., T. G. Ellestad, P. A. Solomon, M. K. Harmon, S. Natarajan, C. A. Noble, R. Murdoch, J. Ambs, J. Tisch, AND G. Sem. Coarse PM Methods Evaluation Study: Study Design and Results. Presented at Region 6 Annual Air Monitoring Meeting, Little Rock, AR, May 11-13, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Heds EPA Database System for Public Access to Human Exposure Data |
06/02/2004
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Croghan, C. Heds EPA Database System for Public Access to Human Exposure Data. Presented at EPA Science Forum 2004, Washington, DC, June 1-3, 2004.
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Human Exposure Database System (HEDS) is an Internet-based system developed to provide public access to human-exposure-related data from studies conducted by EPA's National Exposure Research Laboratory (NERL). HEDS was designed to work with the EPA Office of Research and Development's Environmental Information Management System (EIMS), using links to EIMS to provide searching capabilities and short abstracts for each study and its data sets. The data in HEDS will be from studies with peer reviewed study designs and data quality assurance. Study documents, such as quality assurance plans and sample collection and analysis procedures, are provided. A data dictionary and code table are provided with each data set to detail what information is provided in the data set and to explain the codes. The data are provided in text and database formats which can be used by most commercial software packages. These features provide the data in an easy-to-use format with enough information to evaluate the quality and potential uses of the data. Currently, HEDS contains data from the three National Human Exposure Assessment Survey pilot studies which were conducted in EPA Region 5, Maryland, and Arizona.
The data in HEDS are expected to be used to:
- provide inputs for exposure assessments
- identify subgroups of the general population that may be highly exposed or particularly susceptible to chemicals in their environment
- relate known pollution sources to the actual exposure that people experience
- provide a baseline of the normal range of exposure to chemicals in the general population
- evaluate and improve the accuracy of models developed to predict exposure of people to chemicals
- test different techniques for performing multimedia human exposure studies
The information in HEDS will help communities, states, regions, and other organizations to assess the potential health risks from various chemicals and decide whether steps to reduce those risks are needed.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Heds-EPA Database System for Public Access to Human Exposure Data |
06/02/2004
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Croghan, C. Heds-EPA Database System for Public Access to Human Exposure Data. Presented at EPA Science Forum 2004, Washington, DC, June 1-3, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Laboratory and Field Evaluation of Crystallized Dow 704 Oil on the Performance of the Wins PM2.5 Fractionator |
04/21/2004
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Vanderpool, R., L. Byrd, R. W. Wiener, E. Hunike, M. Labickas, A. Leston, M. Tolocka, F. McElroy, R. Murdoch, S. Natarajan, AND C. A. Noble. Laboratory and Field Evaluation of Crystallized Dow 704 Oil on the Performance of the Wins PM2.5 Fractionator. Presented at Symposium on Air Quality Measurement Methods and Technology - 2004, Research Triangle Park, NC, April 20-22, 2004.
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Subsequent to the 1997 promulgation of the Federal Reference Method (FRM) for monitoring PM2.5 in ambient air, the United States Environmental Protection Agency (USEPA) received reports that the Dow 704 diffusion oil used in the method's WINS fractionator would occasionally crystallize during field use - particularly under wintertime conditions. While the USEPA's survey of site operators revealed that the frequency of occurrence on a nationwide basis was low, concerns were raised that crystallization of the Dow 704 oil during a given sampling event may adversely affect the event's data quality due to possible particle bounce from the crystallized impaction surface.
In response to these concerns, the USEPA and the Connecticut Department of Environmental Protection (CT DEP) jointly conducted a series of specialized tests to determine if crystallized oil adversely affected the performance of the WINS fractionator. In the laboratory, an experimental setup used dry ice to artificially induce crystallization of the diffusion oil under controlled conditions. Using primary calibration aerosols, standard size-selective performance tests of the WINS fractionator showed that neither the position nor the shape of the WINS particle size fractionation curve was substantially influenced by the crystallization of the Dow 704 oil. No large particle bounce from the crystallized impaction surface was observed.
Wintertime field tests were then conducted in Windsor, CT using collocated FRMs equipped with both crystallized and non-crystallized oil. As predicted by results of the laboratory tests, crystallization of the Dow 704 oil did not adversely affect measured PM2.5 concentrations. In 32 collocated PM2.5 tests, regression of measurements with crystallized Dow 704 versus liquid dioctyl sebacate (DOS) oil produced slope, intercept, and R2 values of 0.98, 0.1 ug/m3, and 0.997, respectively.
In 45 additional collocated PM2.5 tests conducted at three U.S. cities, regression of liquid DOS versus liquid Dow 704 produced slope, intercept, and R2 values of 0.995, -0.006 ug/m3, and 0.999, respectively. As a result of these laboratory and field tests, DOS oil has been approved by the USEPA as a substitute for Dow 704 oil. Since the field deployment of DOS oil in 2001, users of this alternative oil have not reported any operational problems associated with its use in the PM2.5 FRM.
This paper has been reviewed in accordance with the United States Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation by the Agency.
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| PRESENTATION |
Laboratory and Field Evaluation of Crystallized Dow 704 Oil on the Performance of the Wins PM2.5 Fractionator |
04/21/2004
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Vanderpool, R., L. Byrd, R. W. Wiener, E. Hunike, M. Labickas, A. Leston, F. McElroy, R. Murdoch, S. Natarajan, AND C. A. Noble. Laboratory and Field Evaluation of Crystallized Dow 704 Oil on the Performance of the Wins PM2.5 Fractionator. Presented at Symposium on Air Quality Measurement Methods and Technology - 2004, Research Triangle Park, NC, April 20-22, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Strategies for Analyzing Polar Organic Compounds in PM2.5 |
04/06/2004
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Kleindienst, T. E., E. O. Edney, AND M. Jaoui. Strategies for Analyzing Polar Organic Compounds in PM2.5. Presented at Organic Speciation in Atmospheric Research Workshop, Las Vegas, NV, April 6, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Comparison of the Speciated VOC Composition at Selected Houston, Texas Area Sites for the Years 1978 and 2000 |
04/21/2004
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Lonneman, W. A. AND R. L. Seila. Comparison of the Speciated VOC Composition at Selected Houston, Texas Area Sites for the Years 1978 and 2000. Presented at Symposium on Air Quality Measurement Methods and Technology - 2004, Research Triangle Park, NC, April 20-22, 2004.
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Comparisons are presented for the C2-C12 volatile organic compounds (VOCs) observed at Houston area sites used for ambient air monitoring during special ozone field study programs conducted in 1978 and 2000. In 1978 the special study called the Houston Ozone Modeling Study consisted of the measurement of VOCs and other pollutants at several ground sites throughout the Houston area to develop a pollutant database for ozone model development and testing. In 2000 the special ozone study called the Texas 2000 Air Quality Study had a similar goal for ozone model testing and consisted predominately of aircraft sampling platforms in addition to the exiting network of ground sampling sites many of which were in operation during the 1978 program. Sampling strategies at the ground sites were different for the two studies. To compare VOCs more directly with the 1978 VOC data a canister collection program was implemented in 2000 at selected sites to collect integrated air samples in canisters during the 0600-0900 and 1300-1600 periods. VOC composition and concentration levels are compared to determine similarities and differences between the 1978 and 2000 periods. In both 1978 and 2000 samples were collected in the Houston Washburn Tunnel to determine VOC composition emitted predominately from vehicular sources. VOC composition will be compared to evaluate hydrocarbon compositions in vehicular tailpipe emissions during the two study periods.
The views expressed in these Proceedings are those of the individual authors and do not necessarily reflect the views and policies of the United States Environmental Protection Agency (EPA). Scientists in EPA have prepared the EPA sections, and those sections have been reviewed in accordance with EPA's peer and administrative review policies and approved for presentation and publication.
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| PRESENTATION |
Can We Determine Penetration Coefficients and Deposition Rates from Field Studies? Results of a 37-Person Panel Study in North Carolina |
10/07/2004
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Wallace, L. A. AND R. W. Williams. Can We Determine Penetration Coefficients and Deposition Rates from Field Studies? Results of a 37-Person Panel Study in North Carolina. Presented at American Association for Aerosol Research, Atlanta, GA, Ocotober 4-8, 2004.
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The contribution of outdoor particles to indoor concentrations is governed by three physical processes: air exchange, penetration, and deposition. Air exchange rates can be measured during field studies, but the other two parameters must be estimated. Over the past few years, half a dozen studies have attempted to estimate these parameters for PM2.5. In almost every case, the attempt has failed when applied to individual homes, although an average value across homes has sometimes been estimated, with uncertain reliability. This presentation attempts to estimate individual parameters for 36 homes, based on an EPA-sponsored study of personal exposures to PM2.5 for 37 persons with hypertension or cardiovascular disease in North Carolina. Personal, indoor and outdoor 24-h samples were collected for 7 days in each of four seasons in 2000-2001. PM results from the study have been previously reported (Williams et al., 2003a,b). All filters (>2000) were analyzed by X-ray fluorescence for sulfur among other elements. Because sulfur has few sources indoors, it can be used as a marker for PM of outdoor origin. Estimates of the penetration coefficient and deposition rate were made using both a linear and nonlinear approach involving the measured air exchange rate or its inverse. The approaches generally agreed among themselves, but both approaches resulted in predictions for five of the 36 homes that were physically impossible.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Bioavailability of Metals in Contaminated Soil and Dust |
05/05/2004
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Bradham, K., S. L. Harper, AND E. A. Coppedge. Bioavailability of Metals in Contaminated Soil and Dust. Presented at 19th Annual Regional Risk Assessors Meeting, Boston, MA, May 3-7, 2004.
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Due to widespread metal contamination, it is necessary to characterize soils suspected of metal contamination and determine if the metal levels in these soils pose a hazard. Metal toxicity is often not directly related to the total concentration of metals present due to a number of modifying factors that depend, in part, on soil physicochemical properties. Soil organic matter, pH, and clay content are a few of the soil physicochemical properties that influence metal toxicity and bioavailability. Current routine practices of investigating the nature and extent of contamination at metal-contaminated sites involve determining total metal content in media, such as soil and dust. Approximately 60-80% of household dust is tracked-in soil. The quantity of toxic element to be used as exposure concentrations in the risk calculation is an assumed percentage of the total content, which may be the bioavailable concentration. Often, very high percentages (near 100%) of total metals are assumed bioavailable. While this assumption is conservative in terms of being protective of human health and the environment, it may not be a reasonable estimate of site conditions because the actual bioavailability of metals has not been assessed. The resulting risk calculations may overestimate the true risk of exposure to site media. Use of the bioavailability approach in conjunction with the total concentration analysis will reduce uncertainty in the risk assessment, thus avoiding unnecessary risk-reduction expenses.
The data from research showing the effect of soil properties on the bioavailability and toxicity of metals in 21 contaminated soils with a wide range of physicochemical properties (pH, % organic carbon, % clay, and amorphous iron and aluminum oxides) will be presented. The combined relationship between biological endpoints (lettuce and earthworms) and soil properties were examined using multiple regression and structural equation modeling (path analysis). Structural equation models proved useful for providing a quantitative causal influence of soil properties on metal bioavailability and toxicity.
In addition, an overview of on-going research projects within the National Exposure Research Laboratory (NERL), Human Exposure and Atmospheric Sciences Division (HEASD) will be presented. These projects include investigating the bioavailability of arsenic from select soil samples contaminated with chromated copper arsenate (CCA) in a controlled field study as well as a sub-set of soils and house dusts collected in the U.S. Department of Housing and Urban Development's (HUD) nationwide "American Healthy Homes Survey". Both projects will produce data under varying environmental conditions to help establish relationships between total concentrations and bioavailable concentrations to yield a better understanding of the absorbed dose of toxic elements.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Demonstration of Human Exposure Tools |
06/02/2004
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Kryak, D. D. Demonstration of Human Exposure Tools. Presented at EPA Science Forum 2004, Washington, DC, June 1-3, 2004.
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The Human Exposure and Atmospheric Sciences Division (HEASD) of the National Exposure Research Laboratory (NERL) conducts research on exposure measurements, human activity patterns, exposure and dose models, and cumulative exposures critical for the Agency to make scientifically based regulatory decisions. For this exposition, the following four (4) major HEASD research projects are presented and demonstrated.
HEDS. The major focus of the Human Exposure Database System (HEDS) is the dissemination of human exposure databases via the World Wide Web. These data collected by HEASD, or its contractors and collaborators will provide needed information on human exposure to researchers, exposure and risk assessors, and the public. HEDS will ensure that data sets on human exposure measurements, activity patterns, and exposure factors are available, easily understood, and readily accessible for exposure analysts and modelers.
CHAD. Personal exposure monitoring studies have demonstrated the critical role that activities play in explaining and predicting variation in exposure and intake dose from all media. NERL has undertaken a number of activity surveys, including the National Human Activity Pattern Survey (NHAPS), and has combined its data and others into the Consolidated Human Activity Database (CHAD). CHAD facilitates queries by the public and exposure modelers needing activity information. Since inhalation, water consumption, and food ingestion can be related to a personal energy expenditure indicator in CHAD, this database facilitates multi-route exposure and uptake dose modeling.
SHEDS. Risk assessors and managers need realistic exposure and dose prediction tools. NERL has developed Stochastic Human Exposure and Dose Simulation (SHEDS) model to improve the scientific basis of exposure assessments. The primary objectives for the SHEDS model are: (1) to provide a refined and evaluated exposure model tool with the capability to address exposures for cumulative risk assessments; and (2) to apply the model to conduct reliable probabilistic population exposure assessments for specific case studies of importance to the Agency (e.g., pesticides, wood preservatives, particulate matter, air toxics).
ERDEM. The Exposure-Related Dose-Estimating Model (ERDEM) is a physiologically based pharmacokinetic (PBPK) modeling framework and a set of applied PBPK models for several different chemicals or groups of related chemicals. ERDEM simulates absorption into the body by multiple routes of entry (e.g., dermal absorption, ingestion, and inhalation), and the distribution, metabolism, and elimination of chemicals. These exposure-to-dose models provide the essential linkage between experimental data and assumptions established by regulation, and dose-response models designed by toxicologists.
Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government, and shall not be used for advertising or product endorsement purposes. With respect to documents available from this server, neither the United States Government nor any of their employees, makes any warranty, express or implied, including the warranties of merchantability and fitness for a particular purpose, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights.
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| PRESENTATION |
Metabolism of 1,1-and 1,3-Dichloropropene: A Mechanism of Bioactivation By Glutathione |
08/31/2004
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Ross, M. K., R. TORNERO-VELEZ, C. Granville, A. Gold, M. V. Evans, AND D. M. DeMarini. Metabolism of 1,1-and 1,3-Dichloropropene: A Mechanism of Bioactivation By Glutathione. Presented at International Society for the Study of Xenobiotics, Vancouver, Canada, August 29-September 2, 2004.
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Glutathione transferases (GST) catalyze the reaction of glutathione (GSH) with haloalkenes via a nucleophilic vinylic substitution mechanism (SNV reaction). The source water contaminants 1,1-dichloropropene and 1,3-dichloropropene, which are under scrutiny by the U.S.EPA, were examined for their ability to produce S-conjugates of GSH and to produce genotoxic species as a result. Following in vitro reactions of 1,1- and 1,3-dichloropropenes with mouse liver cytosol and supplemented GSH, the products were examined by LC-MS and LC-MS/MS analyses. The presence of m/z 382/384 ions following reaction with both 1,1-dichloropropene and 1,3-dichloropropene confirmed the production of stable mono S-conjugates of GSH containing a single Cl atom. LC-MS/MS analysis (SRM m/z 382 - m/z 253) provided a sensitive means of detecting the GSH conjugate of 1,1-dichloropropene since it was much less reactive than 1,3-dichloropropene toward GSH. The significance of GSH conjugation of 1,1-dichloropropene is that Salmonella typhimurium transformed with GSTT5 (rat) or GSTT1 (human) cDNA produced mutations following exposure to 1,1-dichloropropene. The mutations were dependent on the presence of the GST isozyme. In contrast, 1,3-dichloropropene was not mutagenic in the same strains of bacteria. An addition-elimination mechanism is proposed that can account for the production of the stable S-conjugate(s) of 1,1-dichloropropene (m/z 382/384) in addition to the formation of a transient episulfonium ion that may be the genotoxic species responsible for the mutations produced in the bacterial strains.
This work has been funded by the United States Environmental Protection Agency. It has been subjected to Agency review and approved for publication.
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| PRESENTATION |
Advanced Computational Methods in Dose Modeling: Application of Computational Biophysical Transport, Computational Chemistry, and Computational Biology |
06/02/2004
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TORNERO-VELEZ, R., W. Longest, S. Harper, C. C. Dary, AND J. Blancato. Advanced Computational Methods in Dose Modeling: Application of Computational Biophysical Transport, Computational Chemistry, and Computational Biology. Presented at EPA Science Forum 2004, Washington, DC, June 1-3, 2004.
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Computational toxicology (CompTox) leverages the significant gains in computing power and computational techniques (e.g., numerical approaches, structure-activity relationships, bioinformatics) realized over the last few years, thereby reducing costs and increasing efficiency in hazard evaluations, screening assessments, and multi-chemical risk assessments. In this work, we draw upon innovations in CompTox to reduce uncertainties in route-to-route, species-to-species, and other dose extrapolations that are commonly performed in multi-chemical risk assessments. Biophysical transport theory applies computational fluid dynamics and mass transport methodologies to reduce uncertainties in inhalation dosimetry of aerosols and vapors. These computational approaches strengthen the linkage between exposure and absorption of pollutants. Through development of structure-activity relationships, computational chemistry can reduce uncertainties in dose-modeling by reducing bias and imprecision in parameter estimation (e.g., metabolic rate constants, enzyme inhibition constants). Computational biology applies "omics" (e.g., genomics, proteomics, and metabonomics) within a dose-modeling framework to better account for differences in chemical disposition within populations, across species and over a range of exposure regimes. Information on inter-individual differences (i.e. gene polymorphisms), as well as species specific parameters and/or multiple exposure scenarios, may be directly incorporated within a physiologically-based pharmacokinetic model to evaluate their effect on a toxic metabolite.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency Policy.
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| PRESENTATION |
Compound Indicators for Soa Precursors in Ambient PM2.5 |
04/06/2004
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Edney, E. O., T. E. Kleindienst, M. Lewandowski, J. Offenberg, AND M. Jaoui. Compound Indicators for Soa Precursors in Ambient PM2.5. Presented at Organic Speciation in Atmospheric Research Workshop, Las Vegas, NV, April 6, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Summary of EPA's Draft Probabilistic Assessment for Children's Exposure to Cca-Treated Wood |
05/07/2004
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Zartarian, V., J. Xue, A. H. Ozkaynak, W. Dang, G. Glenn, AND L. Smith. Summary of EPA's Draft Probabilistic Assessment for Children's Exposure to Cca-Treated Wood. Presented at 19th Regional Risk Assessors Meeting, Boston, MA, May 3-7, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Summary of EPA's Draft Probabilistic Assessment for Children's Exposures to Cca-Treated Wood |
05/12/2004
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Zartarian, V., J. Xue, A. H. Ozkaynak, W. Dang, G. Glenn, AND L. Smith. Summary of EPA's Draft Probabilistic Assessment for Children's Exposures to Cca-Treated Wood. Presented at Introduction of Human Exposure Analysis Course, Stanford, CA, May 12, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Agricultural Health Study Pesticude Exposure Study |
05/18/2004
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Thomas, K. W. Agricultural Health Study Pesticude Exposure Study. Presented at North Carolina Cooperative Extension Service Special AHS Training Session, Raleigh, NC, May 18, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field for further information.
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| PRESENTATION |
Agricultural Health Study Pesticide Exposure Study |
07/22/2004
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Thomas, K. W. Agricultural Health Study Pesticide Exposure Study. Presented at Joint Meeting of the Agricultural Health Study Exposure Workgroup, Rockville, MD, July 22, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Methods Development for Detection of Pptv Concentrations of Selected Vocs |
04/27/2004
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McClenny, W. A. Methods Development for Detection of Pptv Concentrations of Selected Vocs. Presented at Joint Session of USEPA Regional Laboratory Directors and Laboratory Technical Information Group, Kansas City, KS, April 27, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Effects of Correlated Probabilistic Exposure Model Inputs on Simulated Results |
10/20/2004
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Xue, J., V. Zartarian, AND A. H. Ozkaynak. Effects of Correlated Probabilistic Exposure Model Inputs on Simulated Results. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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In recent years, more probabilistic models have been developed to quantify aggregate human exposures to environmental pollutants. The impact of correlation among inputs in these models is an important issue, which has not been resolved. Obtaining correlated data and implementing a correlated input structure into a simulation model is difficult. This paper assesses the impact of various correlated inputs on EPA's Stochastic Human Exposure and Dose Simulation (SHEDS) model for pesticides.
The object-mouth (OM) nondietary exposure pathway in SHEDS is used to evaluate effect of two and three correlated inputs on the daily and annual averaged OM exposure. The distribution-free technique was used to generate various correlated input distributions for dislodgeable surface residues (V1,ug/cm2), ratio of residue on object mouthed to residue on floor surface (V2), object surface area mouthed per mouthing event (V3,cm2/mouthing event), frequency of object-mouth activity (V4,mouthing events/hr) and saliva removal efficiency(V5). Available published data were used to fit the original distribution.
The relevant equation is: OM exposure (ug/event)=V1*V2*V3*V4*V5*duration of macroactivity (hr/event).
Results with enforced paired and multiple correlated inputs in the model simulations show:
1) If the correlation coefficient of paired inputs is less than 0.5, the relative error of the 95th percentile of daily averaged OM exposure is less than 10%. Any degree of paired correlation will have no impact on any percentile of the annual averaged OM exposure.
2) The spread of the input distribution has an impact on the effect of correlated inputs for daily averaged OM exposure. The bigger the standard deviation of the original distribution, the larger the effect of correlated inputs on daily averaged OM exposure.
3) Correlated inputs affect standard deviation of the OM exposure more than its 95th and 99th percentile.
4) Positive and negative correlations have a cancellation effect; Multiple correlated inputs have an additive effect.
The conclusions are that big correlated input will affect central values and profile of short-term exposure and multiple correlated inputs will have joint impact on the results but correlated inputs will have no impact on predicted annual averaged exposures, and small correlated inputs (correlation coefficient < 0.5) will be insignificant in exposure model predictions even for daily averaged exposures.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Effects of Correlated Probabilistic Exposure Model Inputs on Simulation Results |
10/19/2004
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Xue, J., V. Zartarian, AND A. H. Ozkaynak. Effects of Correlated Probabilistic Exposure Model Inputs on Simulation Results. Presented at International Society for Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Population Exposure and Dose Model for Air Toxics: A Benzene Case Study |
10/19/2004
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Graham, S. E. AND J. M. Burke. Population Exposure and Dose Model for Air Toxics: A Benzene Case Study. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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The EPA's National Exposure Research Laboratory (NERL) is developing a human exposure and dose model called the Stochastic Human Exposure and Dose Simulation model for Air Toxics (SHEDS-AirToxics) to characterize population exposure to air toxics in support of the National Air Toxics Program. SHEDS-AirToxics uses a probabilistic approach to predict the distribution of exposure and dose for a specified population. The model estimates this distribution by simulating the time series of exposure and dose for individuals that demographically represent the population of interest. U.S. census data are used to build the simulation population, and human-activity-pattern data are assigned to each simulated individual to account for interaction with their immediate environment. Each individual's inhalation exposure and dose profile is estimated from the time spent in each location, the concentration in that location, and the activity-specific inhalation rate while in that location. The model also can estimate exposure and dose from ingestion of food containing air toxic residues and from dermal absorption of chemicals while bathing. A daily-averaged exposure and dose for each individual can then be calculated and combined to provide a distribution of exposure and dose for the population.
A case-study application of the model was conducted to estimate benzene exposures for the population of Houston, Texas. Modeled ambient benzene concentrations used as input to the model were produced by EPA's Office of Air Quality Planning and Standards (OAQPS) using the ISC model for all major point, area, and mobile sources in the Houston area. Model inputs for estimating indoor and in-vehicle benzene concentrations were obtained from analysis of available measurement study data. Preliminary results from the case study indicate that benzene exposure and dose varied significantly across the population due to variability in microenvironmental concentrations and the impact of certain activities (e.g., commuting, smoking). The SHEDS-AirToxics inhalation exposure results will also be compared with outputs generated for Houston using OAQPS's Air Pollutant Exposure (APEX) model.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Summary of Research on Perfluorinated Compounds at the U.S. Environmental Protection Agency's Ord/NERL/Mdab |
05/25/2004
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Strynar, M. J. AND A. B. Lindstrom. Summary of Research on Perfluorinated Compounds at the U.S. Environmental Protection Agency's Ord/NERL/Mdab. Presented at Center for Disease Control, Atlanta, GA, May 25, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Organic Carbon Artifacts |
05/14/2004
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Solomon, P. A. AND T. KlamserWilliams. Organic Carbon Artifacts. Presented at State Air Monitoring Working Group, Point Clear, AL, May 13-15, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Organic Carbon Artifact |
06/29/2004
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Solomon, P. A. AND T. KlamserWilliams. Organic Carbon Artifact. Presented at Mid-Atlantic Regional Air Management Association Conference Call, Baltimore, MD, June 29, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Physiologically-Based Pharmacokinetics/Pharmacodynamic Modeling and Cumulative Risk Assessment: Case Study for the N-Methyl Carbmate Pesticides |
06/02/2004
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Lowit, A., C. C. Dary, F. W. Power, J. Blancato, R. W. Setzer, R. Conolly, AND M. Seaton. Physiologically-Based Pharmacokinetics/Pharmacodynamic Modeling and Cumulative Risk Assessment: Case Study for the N-Methyl Carbmate Pesticides. Presented at EPA Science Forum 2004, Washington, DC, June 1-3, 2004.
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The Food Quality Protection Act of 1996 [PL 104-170: 110 STAT. 1513] requires EPA to consider potential cumulative human health risks resulting from aggregate exposure to pesticide chemicals acting through a common mechanism of toxicity. This includes all anticipated dietary exposures and all other exposure for which there is reliable information. In 2001, EPA established the N-methyl carbamate pesticides as a common mechanism group based on their structural characteristics and also similarity and shared ability to inhibit acetylcholinesterase (AChE) by carbamylation of the serine hydroxyl group located in the active site of the enzyme. The Office of Pesticide Programs (OPP) expects to release a preliminary cumulative risk assessment for this group in the spring of 2005. OPP is currently evaluating which method or methods will be used to estimate cumulative risk. A collaborative research effort to develop a physiologically-based pharmacokinetic/pharmacodynamic (PBPK/PD) model for the N-methyl carbamate pesticides has been undertaken by the OPP, ORD's National Health and Environmental Effects Laboratory (NHEERL) and National Exposure Research Lab (NERL), and the CIIT Centers for Health Research. PBPK/PD models are very powerful tools that can account for anatomic structure and physiological and biochemical processes. These models can be used to estimate internal exposure dose or concentrations of parent compounds and/or active metabolites at the target site(s) and also toxicologically relevant effects. Typically, inhibition of AChE is fairly rapid (within hours) for members of the N-methyl carbamate common mechanism group. The time dependant relationship between exposure and effect for this group make the N-methyl carbamates a good case study to aid the EPA in developing a multi-chemical, multi-pathway PBPK/PD models for evaluating cumulative risk.
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| PRESENTATION |
Physiologically-Based Pharmacokinetic/Pharmacodynamic Modeling and Cumulative Risk Assessment: Case Study for the N-Methyl Carbamate Pesticides |
06/02/2004
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Lowit, A., C. C. Dary, F. W. Power, J. Blancato, R. W. Setzer, R. Conolly, AND M. Seaton. Physiologically-Based Pharmacokinetic/Pharmacodynamic Modeling and Cumulative Risk Assessment: Case Study for the N-Methyl Carbamate Pesticides. Presented at EPA Science Forum 2004, Washington, DC, June 1-3, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Population-Based Exposure Modeling for Air Pollutants at EPA's National Exposure Research Laboratory |
05/05/2004
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Burke, J. M. Population-Based Exposure Modeling for Air Pollutants at EPA's National Exposure Research Laboratory. Presented at EPA Region 1 Air Programs Office, Boston, MA, May 5, 2004.
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The US EPA's National Exposure Research Laboratory (NERL) has been developing, applying, and evaluating population-based exposure models to improve our understanding of the variability in personal exposure to air pollutants. Estimates of population variability are needed for EPA to assess what populations are at risk for adverse health outcomes due to air pollutant exposures. Two primary research questions are being addressed: (a) what proportion of the population of interest may be exposed to air pollutant levels where health risks are of concern, and (b) what are the important factors driving the variability in population exposures, and therefore risks. Estimating the uncertainty associated with the findings for these questions is also a key objective of this research.
The Stochastic Human Exposure and Dose Simulation (SHEDS) model has been developed by NERL for addressing these research questions. The SHEDS model is similar in structure to EPA's Hazardous Air Pollutant Exposure Model (HAPEM) used by OAQPS in the National Air Toxics Assessment (NATA). These models estimate population distributions of exposures by simulating the time series of exposure for individuals that demographically represent a user-defined population of interest. US Census demographic data are used to randomly select individuals from the population, and human activity pattern data are randomly assigned to each simulated individual to account for the way people interact with their environment. The differences between these models are primarily in the level of detail and spatial/temporal resolution used in the model calculations. In addition, the SHEDS model utilizes statistical methods for incorporating both variability and uncertainty in the model inputs, and can therefore provide estimates of the uncertainty associated with the model predictions.
The SHEDS model has been applied to particulate matter (PM) and to air toxics using initial case studies that provided information on the impact of different source types (outdoor sources and indoor sources) on exposures for these pollutants, as well as the influence of exposure factors such as the time people spend in various locations (e.g. home, outdoors, in vehicle, workplace, school) and the physical activity level while in those locations. Inhalation exposure to PM2.5 for the population of Philadelphia was investigated using the SHEDS-PM model, and benzene exposure through multiple routes (inhalation, ingestion, dermal) for the Houston population is currently being assessed using the SHEDS-Air Toxics model. Additional PM and air toxics case studies that can address EPA's exposure assessment and risk assessment needs using available data sets would be beneficial for further testing and evaluation of the SHEDS model.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy
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| PRESENTATION |
A Preliminary PBPK Model of Pyrethroid Pesticides for Application in Environmental Risk Assessment |
07/17/2004
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Dary, C. C., M. Dellarco, J. N. Blancato, AND R. TORNERO-VELEZ. A Preliminary PBPK Model of Pyrethroid Pesticides for Application in Environmental Risk Assessment. Presented at X2004 - Exposure Assessment in a Changing Environment, Utrecht, The Netherlands, June 16-18, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Vapor Sampling Device for Interface With Microtox Assay for Screening Toxic Industrial Chemicals |
11/16/2004
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Rogers, K. R. AND G. L. Robertson. Vapor Sampling Device for Interface With Microtox Assay for Screening Toxic Industrial Chemicals. Presented at Society of Environmental Toxicology and Chemistry, Portland, OR, Novembr 14-18, 2004.
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A time-integrated sampling system interfaced with a toxicity-based assay is reported for monitoring volatile toxic industrial chemicals (TICs). Semipermeable membrane devices (SPMDs) using dimethyl sulfoxide (DMSO) as the fill solvent accumulated each of 17 TICs from the vapor phase. Uptake kinetics experiments for one of these compounds (acrolein) indicated that it was significantly sequestered (i.e., 10 percent of the 24 hr maximum) in as little as 10 min and was concentrated by a factor of over 200 in 24 hr as measured using both mass and toxicity assays. The effect of each of the TICs on the Microtox bacterial luminescence assay was determined both from a direct assay and a vapor accumulation assay using SPMDs. Microtox EC50 values (concentration yielding 50 percent inhibition) were determined for each of the TICs analyzed and ranged from 0.070 parts per million volume (ppmv) for diketene to 322 ppmv for 1,2-dibromoethane. The rank order of the Microtox EC50 values for each compound measured directly from liquid was similar but not identical to the Apparent (App) EC50 values determined from the vapor accumulation assay. The ratios of the EC50 and the AppEC50 values were used to calculate toxicity-derived Concentration Factors (i.e., the toxicity equivalents of compound that concentrate from vapor into the SPMD). These Concentration Factors ranged from 17 to 5400 and primarily reflected differences in partitioning characteristics between air and DMSO for each compound. Acrolein was chosen as a representative compound for the vapor dilution experiment and it showed a toxicity-based detection limit of 19 mg/m3 which was less than the LD-50 by a factor of 100, but greater than the National Institute for Occupational Safety and Health (NIOSH) 40 hr/week exposure limit also by a factor of 100. Consequently, for acrolein, this system in its current configuration, shows potential for development as an initial screening tool for mid to high acute vapor phase toxicity determinations.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Exhaled Breath Analysis for Human Exposure Research |
09/25/2004
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Lindstrom, A. B. Exhaled Breath Analysis for Human Exposure Research. Presented at Conference Breath Gas Analysis in Medical Diagnostics, Dornbirn, Austria, September 23-26, 2004.
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Exhaled breath collection and analysis has historically been used in environmental research studies to characterize exposures to volatile organic compounds. The use of this approach is based on the fact that many compounds present in blood are reflected in the breath, and that unlike blood, breath collection is noninvasive and generally well tolerated by study subjects. This research has focused on demonstrating exposures to volatile compounds, establishing conclusive links between specific activities and corresponding body burdens of xenobiotics, characterizing uptake and elimination kinetics, and illuminating relevant pathways of exposure. In the past few years exhaled breath analysis has evolved to the point where it is now being used to help characterize biological responses associated with exposures to environmental pollutants.
This presentation will explore historical and newly emerging methods for the collection and analysis of exhaled breath for use in environmental exposure assessment studies. We will discuss their applicability and limitations with respect to environmental research. Particular emphasis will be placed on new methods and their utility for examining exhaled biomarkers of environmental pollution.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
The Unique Value of Breath Biomarkers for Estimating Phamacokinetic Rate Constants and Body Burden from Random/Intermittent Dose |
09/25/2004
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Pleil, J. D. AND D. Kim. The Unique Value of Breath Biomarkers for Estimating Phamacokinetic Rate Constants and Body Burden from Random/Intermittent Dose. Presented at Breath Gas Analysis for Medical Diagnostics, Dornbirn, Austria, September 23-26, 2004.
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Biomarker measurements are used in three ways: 1) evaluating the time course and distribution of a chemical in the body, 2) estimating previous exposure or dose, and 3) assessing disease state. Blood and urine measurements are the primary methods employed. Of late, it has been recognized that collecting exhaled breath is an attractive alternative to blood and urine sampling because it is less invasive, and is not restricted by sample volume or time frame. Breath volume and frequency of sampling are essentially unlimited; the subject never runs out sample and one can collect even adjacent breaths with existing technology. Furthermore, there is a fundamental difference between blood and breath measurement in that blood levels report only the status quo at the time of collection, whereas exhaled breath is reflective of current blood levels as well as an elimination mechanism allowing calculation of real time removal rates. Therefore, from a mathematical standpoint, the time courses of blood and breath are interpreted differently and give complementary information.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Monitoring the Air for Toxic and Genotoxic Compounds |
07/07/2004
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Rogers, K. R. Monitoring the Air for Toxic and Genotoxic Compounds. Presented at Green Chemistry Gordon Conference, Bristol, RI, July 4-9, 2004.
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A time-integrated sampling system interfaced with a toxicity-based assay is reported for monitoring volatile toxic industrial chemicals (TICs). Semipermeable membrane devices (SPMDs) using dimethyl sulfoxide (DMSO) as the fill solvent accumulated each of 17 TICs from the vapor phase. Uptake kinetics experiments for one of these compounds (acrolein) indicated that it was significantly sequestered (i.e., 10 percent of the 24 hr maximum) in as little as 10 min and was concentrated by a factor of over 200 in 24 hr as measured using both mass and toxicity assays. The effect of each of the TICs on the Microtox bacterial luminescence assay was determined both from a direct assay and a vapor accumulation assay using SPMDs. The response of the IQ-tox assay based on Daphnia magna was also investigated for the 17 TICs. EC50 values (i.e., concentration yielding 50% inhibition of measured response) were similar to those observed for the Mocrotox assay.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
ELISA Measurement for Stachylysin |
07/29/2004
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Van Emon, J. M. AND S. J. Vesper. ELISA Measurement for Stachylysin. Presented at American Society for Testing Materials, Boulder, CO, July 25-30, 2004.
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The consumption of food commodities contaminated with the mold, Stachybotrys charatrum, has a long history of causing severe illness, and even death, in humans and animals. More recently, negative health effects have been linked to indoor inhalation exposures to S. chartarum. For these health effects to be documented, a mechanistic biomarker of exposure must be demonstrated. An enzyme linked- immunosorbent assay (ELISA) was developed for stachylysin, a proteinaceous hemolysin obtained from cultures of S. chartarum. The ELISA was highly selective to stachylysin and had an average limit of detection of 2 ppb depending upon the sample matrix. The conidia from several other molds showed a negligible reaction in the assay indicating the specificity of stachylysin to S. chartarum. The ELISA was used to analyze environmental samples from mold- contaminated buildings and biological samples obtained from individuals with known mold exposures. Stachylysin was quantified by the ELISA in spore, wallboard, mycelial and dust samples, and in the serum of adults exposed to S. chartarum in water-damaged environments. All control sera was negative for stachylysin. Thus, the analysis of stachylysin in serum may provide a useful measurement of human exposure to the mold. If stachylysin is a relevant biomarker, its determination in environmental samples may be useful for assessing and managing risk for indoor mold exposures.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy. Mention of trade names or commercial products does not constitute endorsement or recommendation by EPA for use.
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| PRESENTATION |
U.S. EPA Ord's Receptor Model Development and Applications |
10/27/2004
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Eberly, S. I. U.S. EPA Ord's Receptor Model Development and Applications. Presented at Regional and Global Perspectives on Haze: Causes, Consequences & Controversies Visability Specialty Conference, Asheville, NC, October 25-29, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Air Toxics Exposure Assessment Activities at EPA |
08/04/2004
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Watkins, T. H. Air Toxics Exposure Assessment Activities at EPA. Presented at MIT Air Toxics Symposium, Boston, MA, August 3-5, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Application of Erdem in Risk Assessment: Health Effects Division's Risk Assessor Training and Certification Program |
08/11/2004
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Blancato, J., C. C. Dary, M. S. Okino, F. W. Power, A. Ruiz, AND R. TORNERO-VELEZ. Application of Erdem in Risk Assessment: Health Effects Division's Risk Assessor Training and Certification Program. Presented at Health Effects Division's Risk Assessor Training and Certification Program, Washington, DC, August 11-12, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Bioavailability of Arsenic, Chromium, and Copper for Cca Contaminated Soils and Dust |
11/12/2004
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Coppedge, E. A., S. L. Harper, K. Bradham, AND R. Keys. Bioavailability of Arsenic, Chromium, and Copper for Cca Contaminated Soils and Dust. Presented at The Southeastern Regional Meeting of the American Chemical Society, Research Triangle Park, NC, November 10-13, 2004.
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It is estimated that 70% of single family homes have pressure-treated wood decks or porches and 14% of playground equipment uses pressure-treated wood. This popular form of wood contains chromated copper arsenate (CCA), which is an antimicrobial pesticide and is currently undergoing a rigorous risk assessment by the U.S. Environmental Protection Agency (EPA). Although manufacturers signed an agreement with EPA for voluntary cancellation of the registration of CCA-treated wood for residential uses beginning January 1, 2004, pressure-treated wood typically lasts 20 - 40 years, thus posing a potential for long-term exposure. The following projects will produce data under varying environmental conditions to help establish relationships between total concentrations and bioavailable concentrations to yield a better understanding of the absorbed dose of toxic elements. The bioavailability approach seeks to reduce uncertainty of total concentration analyses, which may over or under estimate health hazard, provide inaccurate risk assessments, and inappropriate risk-reduction expenses.
EPA's National Exposure Research Laboratory (NERL) is collaborating with the U.S. Department of Housing and Urban Development in the nationwide "American Healthy Homes Survey", which will provide data from a national cross-section of residential soils collected near CCA-treated wood outside homes and indoor house dusts. NERL is also collaborating with EPA's National Risk Management Research Laboratory (NRMRL) on a research project evaluating the effectiveness of coatings in reducing dislodgeable arsenic (As) from CCA-treated wood. NERL's main role in the project is to use bioassays, including earthworms and lettuce, to investigate the bioavailability of As, Chromium (Cr), and Copper (Cu) in the soil below coated CCA mini decks. Results to date show that total arsenic in the mini decks field control soils are below background concentrations. The results to date for both projects will be presented.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Use of Pelleted Lettuce Seeds in Bioavailability Studies |
11/12/2004
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Cummings, K. T., R. Keys, K. Bradham, S. L. Harper, M. MedinaVera, AND A. AbuShakra. Use of Pelleted Lettuce Seeds in Bioavailability Studies. Presented at The Southeastrn Regional Meeting of the American Chemical Society, Research Triangle Park, NC, November 10-13, 2004.
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Lettuce (Latuca sativa L., cv. Buttercrunch) is one of the most common and sensitive test organisms, among plants, used in toxicology and bioavailability studies. Much of the available lettuce seeds in commercial channels are pelleted to allow for precision machine planting. The use of pelletized seeds in plant studies would allow for a much greater diversity of seeds resources to be utilized. The following work compared the germination of pelleted, de-pelleted, and raw lettuce seeds to see if the pelleted seeds could be used in such studies. Pelleted and raw lettuce seeds were obtained from commercial sources. Pelleted seeds were de-pelleted in the lab by placing 100 seeds in a 50ml centrifuge tube, adding 30ml deionized water, and shaking gently for 3 min. The mix was filtered on qualitative filter paper in a Buchner funnel with vacuum for 3 min, and the filter paper was removed to air dry on the bench. Pelleted seeds contained approximately 10% seeds by weight, with the 90% pellet comprised of soluble and insoluble components. Pelleted, de-pelleted, and raw seeds were germinated in Petri dishes on two layers of germination blotter paper at 15oC with a 16h light/8h dark photoperiod (90 umol m-2 s-1 photosynthetic photon flux density (PPFD)). Total germination of the pelleted, de-pelleted, and raw seeds was identical (>90%) at 7 days. The de-pelleted and raw seeds had identical germination and growth time course plots. The pelleted seeds lagged behind in germination slightly up to 4 days, but were identical to the de-pelleted and raw seeds by 5 days. The work indicates that pelleted lettuce seeds could be used in plant toxicology or bioavailability studies provided such studies were longer than approximately 5-7 days.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Use of Pelleted Lettuce Seeds in Bioabailability Studies |
11/13/2004
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Cummings, K. T., R. Keys, K. Bradham, S. L. Harper, M. MedinaVera, AND A. AbuShakra. Use of Pelleted Lettuce Seeds in Bioabailability Studies. Presented at The Southeastern Regional Meeting of the American Chemical Society, Research Triangle Park, NC, November 10-13, 2004.
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| Abstract:
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Lettuce (Latuca sativa L., cv. Buttercrunch) is one of the most common and sensitive test organisms, among plants, used in toxicology and bioavailability studies. Much of the available lettuce seeds in commercial channels are pelleted to allow for precision machine planting. The use of pelletized seeds in plant studies would allow for a much greater diversity of seeds resources to be utilized. The following work compared the germination of pelleted, de-pelleted, and raw lettuce seeds to see if the pelleted seeds could be used in such studies. Pelleted and raw lettuce seeds were obtained from commercial sources. Pelleted seeds were de-pelleted in the lab by placing 100 seeds in a 50ml centrifuge tube, adding 30ml deionized water, and shaking gently for 3 min. The mix was filtered on qualitative filter paper in a Buchner funnel with vacuum for 3 min, and the filter paper was removed to air dry on the bench. Pelleted seeds contained approximately 10% seeds by weight, with the 90% pellet comprised of soluble and insoluble components. Pelleted, de-pelleted, and raw seeds were germinated in Petri dishes on two layers of germination blotter paper at 15oC with a 16h light/8h dark photoperiod (90 umol m-2 s-1 photosynthetic photon flux density (PPFD)). Total germination of the pelleted, de-pelleted, and raw seeds was identical (>90%) at 7 days. The de-pelleted and raw seeds had identical germination and growth time course plots. The pelleted seeds lagged behind in germination slightly up to 4 days, but were identical to the de-pelleted and raw seeds by 5 days. The work indicates that pelleted lettuce seeds could be used in plant toxicology or bioavailability studies provided such studies were longer than approximately 5-7 days.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Current and Emerging Techniques for Characterizing Tropospheric Aerosols |
09/01/2004
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Vallero, D. A. Current and Emerging Techniques for Characterizing Tropospheric Aerosols. Presented at Mechanics in the Environment Seminar, Durham, NC, September 1, 2004.
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Particulate matter generally includes dust, smoke, soot, or aerosol particles. Environmental research addresses the origin, size, chemical composition, and the formation mechanics of aerosols. In the troposphere, fine aerosols (e.g. with diameters < 2.5 um) remain suspended until aggregation, agglomeration or flocculation to form larger particles, leading to sedimentation and deposition. Aerosols are often hygroscopic nuclei that attract water vapor and form droplets. The finer suspended particles are human health hazards, since once breathed into the lungs, they are trapped and remain there to cause a number of respiratory problems. The ability to measure and to characterize aerosols has been evolving, so that numerous methods are presently available. However, several challenges remain; including improved gravimetric for very small particles (< 1 um) and optical techniques for small particles (< 2.5 um), real-time and on-line measurements of chemical composition (e.g. single particle mass spectrometry), and means for enhanced precision and accuracy (e.g. decreased losses in sampling apparatus, including pressure drops, particle bounce, and chemical reactions on filters, as well as remote and portable measurement and analytical capabilities).
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Evidence of Secondary Aerosol Formation from the Photooxidation of Monoterpenes in the Southeastern United States |
10/05/2004
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Jaoui, M., E. W. Corse, T. E. Kleindienst, M. Lewandowski, J. Offenberg, AND E. O. Edney. Evidence of Secondary Aerosol Formation from the Photooxidation of Monoterpenes in the Southeastern United States. Presented at American Association for Aerosol Research 2004 Annual Conference, Atlanta, GA, October 4-8, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Elements of Quality Assurance in Monitoring Volatile Organic Compounds at Trace Levels |
10/20/2004
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McClenny, W. A. Elements of Quality Assurance in Monitoring Volatile Organic Compounds at Trace Levels. Presented at 14th Annual Quality Assurance Conference, Dallas, TX, October 18-22, 2004.
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Monitoring for air toxic VOCs at sub-ppbv concentrations has been demonstrated in the TO-15 Supplement recently published by the EPA. While this approach uses specially prepared canisters for sampling and storage of the air samples, the use of solid adsorbents has now been investigated for the same purpose. Examples of the results obtained with both canisters and solid adsorbents are given along with a discussion of the quality assurance guidelines in both cases.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Multi-Site Comparison of Mass and Major Chemical Components Obtained By Collocated Stn and Improve Chemical Speciation Network Monitors |
10/05/2004
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Solomon, P. A., T. KlamserWilliams, P. P. Egeghy, D. Crumpler, J. Rice, L. Ashbaugh, AND C. McDade. Multi-Site Comparison of Mass and Major Chemical Components Obtained By Collocated Stn and Improve Chemical Speciation Network Monitors. Presented at American Association for Aerosol Research 2004 Annual Conference, Atlanta, GA, October 4-8, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Validation of a Method for Estimating Long-Term Exposures Based on Short-Term Measurements |
10/18/2004
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Wallace, L. A. AND R. W. Williams. Validation of a Method for Estimating Long-Term Exposures Based on Short-Term Measurements. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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A method for estimating long-term exposures from short-term measurements is validated using data from a recent EPA study of exposure to fine particles. The method was developed a decade ago but data to validate it did not exist until recently. In this paper, data from repeated visits to 37 persons over one year (up to 28 measurements per person) are used to test the model. Both fine particle mass and elemental concentrations measured indoors, outdoors, and on the person are examined. To provide the most stringent test of the method, only two single-day distributions are randomly selected for each element to predict the long-term distributions. The precision of the method in estimating the long-term geometric mean and geometric standard deviation appears to be on the order of 10%, with no apparent bias. The precision in estimating the 99th percentile ranges from 19-48%, again without obvious bias. It appears likely that the precision can be improved by selecting a number of pairs of single-day distributions instead of just one pair. Occasionally the method fails to provide an estimate for the long-term distribution. In that case, a repeat of the selection procedure using a slightly different basis for the random selection of measurements can provide an estimate. Although the method assumes a log-normal distribution, most of the distributions tested failed the Chi-square test for log-normality. Therefore the method appears suitable for application to distributions that depart from log-normality.
Although this work was reviewed by EPA and approved for publication, it may not reflect official Agency policy.
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| PRESENTATION |
Organic Speciation Sampling Artifacts |
10/06/2004
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Sihabut, T., J. W. Ray, A. Northcross, AND S. R. McDow. Organic Speciation Sampling Artifacts. Presented at American Assocation for Aerosol Research, 2004 Annual Conference, Philadelphia, PA, October 4-8, 2004.
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Sampling artifacts for molecular markers from organic speciation of particulate matter were investigated by analyzing forty-one samples collected in Philadelphia as a part of the Northeast Oxidant and Particulate Study (NEOPS). Samples were collected using a high volume sampler with two quartz fiber filters in series. Altogether thirty-one species including alkanes (C23-C31), hopanes (C27-C31), n-alkanoic acids (C10-C22), and aliphatic dicarboxylic acids (C3 to C9) were analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that species with low molecular weight or high vapor pressure had significant amounts of artifacts on the backup filters. Particulate organic species can be classified into the following three categories: 1) the amount collected on the backup filter was often a large fraction of the amount collected on the front filters (n-alkanes C23 and C24, n-carboxylic acids C10 to C14); 2) the amount collected on the backup filter was consistently a small fraction of the amount collected on the front filter (n-alkanes C25 to C28, hopanes C27 to C30, n-carboxylic acids C15 to C18, and dicarboxylic acids C3 to C9); 3) rarely observed on backup filters (n-alkanes C29 to C31, hopanes C31 and C32).
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency Policy.
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| PRESENTATION |
Exposure Assessment Concepts from Border Xxi and Border 2012 Environmental Health Projects |
10/07/2004
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Mukerjee, S. Exposure Assessment Concepts from Border Xxi and Border 2012 Environmental Health Projects. Presented at US-Mexico Border 2012 Air Policy Forum, Tijuana, Baja California, Mexico, October 6-7, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Sampling Duration Dependence of Semi-Continuous Organic Carbon Measurements on Steady State Secondary Organic Aerosols |
10/07/2004
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Offenberg, J., M. Lewandowski, T. E. Kleindienst, E. O. Edney, M. Jaoui, AND E. W. Corse. Sampling Duration Dependence of Semi-Continuous Organic Carbon Measurements on Steady State Secondary Organic Aerosols. Presented at American Association for Aerosol Research 2004 Annual Conference, Atlanta, GA, October 4-8, 2004.
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Semi-continuous organic carbon concentrations were measured through several experiments of statically generated secondary organic aerosol formed by hydrocarbon + NOx irradiations. Repeated, randomized measurements of these steady state aerosols reveal decreases in the observed concentration with increasing sampling time for a given sampling flow rate. More pronounced changes are observed when a gas phase denuder is not upstream of the semi-continuous instrument. Initial results indicate that longer sampling integrations times will minimize the influence of the apparent sampling artifacts. Furthermore, these experiments indicate that reported organic carbon concentrations collected using one set of sampling time/flow rate parameters may not be comparable to other sampling protocols, especially when protocols involve short duration sampling, or when integrations periods are most dissimilar. Extrapolation of these results to ambient measurements of organic carbon also suggests that comparison of concentrations measured via differing instrumental protocols may lead to results which are not directly comparable.
This work has been funded wholly or in part by the United States Environmental Protection Agency under Contract 68-D-00-206 to ManTech Environmental Technology, Inc. Although this work was reviewed by the EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Development of a Bayesian Hierarchical Model for Personal Exposures to Particulate Matter |
10/19/2004
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McBride, S., R. W. Williams, AND J. P. Creason. Development of a Bayesian Hierarchical Model for Personal Exposures to Particulate Matter. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Mercury Species Measured Off the Atlantic Coast of South Florida |
09/28/2004
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Landis, M. S. Mercury Species Measured Off the Atlantic Coast of South Florida. Presented at EPA Region 4 Science Meeting, Atlanta, GA, September 28-29, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Human Exposure Modeling for Air Pollutants Using Sheds |
10/05/2004
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Graham, S. E. AND J. M. Burke. Human Exposure Modeling for Air Pollutants Using Sheds. Presented at Northwest International Air Quality Environmental Science and Technology Consortium Workshop, Spokane, WA, October 5-6, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Speciation of Organics for Apportionment of PM2.5 (Soap) in the New York City Metropolitan Area |
10/06/2004
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Mazurek, M. A., M. Li, S. R. McDow, J. Graham, D. Felton, T. McKenna, C. Pietarinen, A. Leston, AND S. Bailey. Speciation of Organics for Apportionment of PM2.5 (Soap) in the New York City Metropolitan Area. Presented at American Association of Aerosol Research 2004 Annual Conference, Philadelphia, PA, October 4-8, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Levels of Polycyclic Aromatic Hydrocarbons and Pyrethroid Pesticides in the Homes, Day Care Centers, and Urine of 127 Ohio Preschool Children |
10/19/2004
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Chuang, J. C., N. K. Wilson, R. A. Lordo, M. C. Brinkman, C. Lyu, S. M. Gordon, M. K. Morgan, AND L. S. Sheldon. Levels of Polycyclic Aromatic Hydrocarbons and Pyrethroid Pesticides in the Homes, Day Care Centers, and Urine of 127 Ohio Preschool Children. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Composition of PM 2.5 During the Summer of 2003 in Research Triangle Park, North Carolina |
10/07/2004
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Lewandowski, M., T. E. Kleindienst, M. Jaoui, AND E. O. Edney. Composition of PM 2.5 During the Summer of 2003 in Research Triangle Park, North Carolina. Presented at American Association of Aerosol Research 2004 Annual Conference, Atlanta, GA, October 4-8, 2004.
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Ambient PM2.5 contains a complex mixture of organic and inorganic compounds which may be derived from primary emission to the atmosphere or from secondary reaction processes. Determining the relative contributions of primary emissions versus secondary production and understanding the sources of secondary products are of great importance for the development of effective control strategies for reducing ambient PM2.5 levels.
A short-term field study was carried out in Research Triangle Park to examine the inorganic and organic components of PM2.5. Samples were collected during seven 48-hour periods between July and September of 2003. The general composition of the collected PM2.5 was evaluated using a combination on gravimetric analysis, ion chromatography, and a thermal-optical method for the determination of carbon content. The ambient PM2.5 mass concentrations measured in this summer field study ranged between 6.1 and 33.7 µg/m3, with an average value of ~20 µg/m3. On average, the PM2.5 samples contained 6.4 µg/m3 sulfate, 2.2 µg/m3 ammonium, very little nitrate (0.01 µg/m3), and 5.8 µg/m3 total carbon.
For structural characterization of the organic fraction, the collected ambient PM2.5 was solvent extracted and derivatized using a single, double, or triple derivatization technique based upon the BF3-methanol, BSTFA, and PFBHA techniques. The resulting derivatives were analyzed by GC-MS in EI and methane-CI modes. Interpretation of the EI and CI mass spectra provide important information, leading to unambiguous identification of compounds comprising PM2.5. GC-MS analyses of the field samples showed the presence of seven compounds that we have tentatively identified in laboratory irradiations of monoterpence/NOx that could serve as tracer compounds for monoterpene SOA: 3-isopropyl pentanedioic acid, 3-acetyl pentanedioic acid, 3-carboxy heptanedioic acid, 3-acetyl hexanedioic acid, 3-(2-hydroxy-ethyl)-2,2-dimethyl-cyclobutane-carboxylic acid, and two triol compounds. GC-MS analysis also revealed two additional compounds, 2,3 dihydroxy-4-oxopentanoic acid and ,3-dihydroxy-4-oxobutanoic acid, which are observed in laboratory irradiations of toluene/NOx and may serve as tracer compounds for aromatic SOA.
This work has been funded wholly or in part by the United States Environmental Protection Agency under Contract 68-D-00-206 to ManTech Environmental Technology, Inc. It has been subjected to Agency review and approved for publication.
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| PRESENTATION |
Longitudinal Study of Young Children's Exposures in Their Homes to Selected Pesticides, Phthalates, Brominated Flame Retardants, and Perfluorinated Chemicals (a Children's Environmental Exposure Research Study Cheers) |
10/06/2004
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Tulve, N. S. AND R. C. Fortmann. Longitudinal Study of Young Children's Exposures in Their Homes to Selected Pesticides, Phthalates, Brominated Flame Retardants, and Perfluorinated Chemicals (a Children's Environmental Exposure Research Study Cheers). Presented at American Chemistry Council Peer Advisory Committee Meeting, Arlington, VA, October 6, 2004.
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The U.S. Environmental Protection Agency's (EPA) National Exposure Research Laboratory (NERL) is conducting a study of young children's exposures to chemicals in the home. The American Chemistry Council (ACC) is partnering with the EPA to enhance an existing EPA study of children's exposure to pesticides in residences by including additional measurements and data collection to evaluate the potential exposures of very young children to three classes of organic compounds that may be found in residences. The study, which will start in the fall of 2004, is a two-year longitudinal study in Jacksonville, Florida originally designed to measure the aggregate exposures for children 3 months to 3 years of age to current use indoor residential pesticides (primarily pyrethroids). Approximately 60 infants/toddlers will be enrolled in the study in two cohorts: (1) infants recruited into the study soon after birth, and, (2) children recruited into the study at approximately one year of age. Participant recruitment will be performed at Duval County Health Department clinics, local hospitals, and other child-friendly locations in the County. The study involves up to six visits during the two-year period during which measurements will be performed for all pathways and routes of exposure. Urine samples will be collected and analyzed for pesticide and phthalate metabolites by the Centers for Disease Control and Prevention, another partner in the study.
The ACC-funded enhancement to the study will allow the EPA to perform aggregate exposure estimates for the children in the existing study to a suite of phthalates. The exposures will be estimated using measurements of phthalates for all pathways and routes of exposure. Results of aggregate exposure estimates from the environmental and diet measurements will be compared to biomarker data from urine samples collected from the study participants. Additionally, using resources from the ACC, measurements will be made to evaluate the potential exposures of the children in the study to selected polybrominated diphenyl ethers (PBDEs) and to selected perfluorinated compounds in their residences. Although aggregate exposure estimates will not be performed for these two classes of compounds, data in the study will provide information on the potential magnitude of exposure and the temporal and spatial variability.
This study will provide critically needed data on very young children's exposures to chemicals in their homes. Data will be used to gain a better understanding of the factors affecting children's exposures, the impact of children's age and activities on their exposures, the important routes and pathways of exposures, and the use of biomarkers as indicators of exposure for pesticides and phthalates.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect Agency policy.
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| PRESENTATION |
Radiocarbon Measurement of the Biogenic Carbon Contribution to PM 2.5 Aerosol Near Tampa, Fl |
10/07/2004
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Lewis, C. W., D. C. Stiles, AND T. D. Atkeson. Radiocarbon Measurement of the Biogenic Carbon Contribution to PM 2.5 Aerosol Near Tampa, Fl. Presented at American Association for Aerosol Research, 2004 Annual Conference, Atlanta, GA, October 4-8, 2004.
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| Abstract:
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Use of An Integrated Approach to Evaluate Young Children's Activities |
10/19/2004
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Tulve, N. S., P. A. Jones, T. R. McCurdy, R. C. Fortmann, AND C. Croghan. Use of An Integrated Approach to Evaluate Young Children's Activities. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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Linking a young child's activity pattern data with the environmental, biological, and personal samples that are collected during an exposure assessment is important in evaluating potential exposures and dose associated with environmental contaminants. A number of different approaches have been taken to characterize children's activity levels, including videotaping of "normal" activities of the children, completing a time activity diary or "timeline" (a simplified activity diary) by the primary caregiver, and the wearing of an accelerometer by the child.
However, there is no documented relationship between the predictability and reliability of using an accelerometer, activity time line or diary, and videotaped segments to classify activity levels of a child going about his or her daily activities. Furthermore, the use of an accelerometer to relate activity level to potential contaminant exposure and intake/uptake dose rate is novel. A pilot study was performed to collect activity data from young children (n=9, <24 months) using all three methods in an integrated manner. Because up to 4 days of information are available, intra-individual variability in the data can also be addressed. Results from this pilot study are described and the concordance among the three methods of data collecting are tested and discussed.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Pesticide Measurement Results from the First National Environmental Survey of Child Care Centers |
10/19/2004
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Tulve, N. S., P. A. Jones, R. C. Fortmann, AND C. Croghan. Pesticide Measurement Results from the First National Environmental Survey of Child Care Centers. Presented at International Society for Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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| Abstract:
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Approximately 13 million children are placed in non-parental child care during the work day; however, children's exposures to chemicals in child care centers have not been characterized. To address this data gap, three federal agencies teamed to characterize contaminants in child care centers. The US Department of Housing and Urban Development, in collaboration with the US Consumer Product Safety Commission and the US Environmental Protection Agency, characterized young children's potential exposures to lead, allergens, and pesticides in a randomly-selected nationally representative sample of licensed institutional child care centers. Multi-stage sampling with clustering was used to select approximately 150 child care centers in 30 primary sampling units in the United States. Child care centers were recruited into the study by telephone interviewers. Samples for pesticides, lead, and allergens were collected at multiple locations in each child care center by field technicians. Wipe samples from indoor surfaces (floors, tabletops, desks, etc.) and soil samples were collected at the child care centers. A wide variety of pesticides were detected in the environmental measurements with chlorpyrifos (0.003-63 ng/cm2 of surface; 9-881 ng/g of soil), diazinon (0.004-15 ng/cm2 of surface; 6-89000 ng/g of soil), and cis- (0.001-103 ng/cm2 of surface; 10-116 ng/g of soil) and trans- (0.002-219 ng/cm2 of surface; 2-118 ng/g of soil) permethrin detected in >60% of the child care centers. Based on the questionnaire responses, pyrethroids were the most commonly used pesticides among child care centers applying pesticides. Furthermore, among the 63% of centers applying pesticides, the number of pesticides in the center ranged from 1 to 10 and the frequency of use ranged from 1 to 107 times annually. More detailed pesticide results will be presented.
Although this work was reviewed by EPA, HUD, and CPSC, and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Characterizing Transfer of Surface Residues to Skin Using a Video-Fluorescent Imaging Technique |
10/19/2004
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CohenHubal, E. A., P. P. Egeghy, M. G. Nishioka, AND W. Ivancic. Characterizing Transfer of Surface Residues to Skin Using a Video-Fluorescent Imaging Technique. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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Surface-to-skin transfer of contaminants is a complex process. For children's residential exposure, transfer of chemicals from contaminated surfaces such as floors and furniture is potentially significant. Once on the skin, residues and contaminated particles can be transferred back to the contaminated surface during subsequent contact, lost by dislodgement or washing, or transferred into the body by percutaneous absorption or hand-to-mouth activity. Increased understanding of the relevant factors influencing transfers from contaminated surfaces to skin and the resulting dermal-loading will reduce uncertainty in exposure assessment.
In a previously reported study, a fluorescence imaging system was developed, tested and used to measure transfer of riboflavin residues from surfaces to hands (Ivancic et al. Ann. Occup. Hyg, in press ; Cohen Hubal et al., JEAEE, in press). Parameters evaluated included: surface type, surface loading, contact motion, pressure, duration, and skin condition. Results of this initial study indicated that contact duration and pressure were not significant for the range of values tested, but that there are potentially significant differences in the transfer efficiencies of different compounds.
In this study, the experimental methods were refined and additional transfer data collected. A second tracer, Uvitex OB, having very different physicochemical properties than riboflavin, was also evaluated to better characterize the range of transfers that may be expected for a variety of compounds. The fluorescent tracers were applied individually to surfaces and the transfers to skin were measured after each of seven repeated hand contacts with the surface. Application loadings of 0.2 and 2.0 µg/cm2 were used to approximate loadings that occur in homes after product use.
Results of this study indicate that for the average of all experiments, dermal loadings of both tracers increase in a linear fashion through the seventh contact. Dermal loading of Uvitex tends to increase at a higher rate than dermal loadings of riboflavin. At the 0.2 µg/cm2 surface loading, Uvitex transfers more efficiently than riboflavin.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Urinary Levels of 2,4-D and 3,5,6-Trichloro-2-Pyridinol for Spouses and Children of Pesticide Applicators in the Agricultural Health Study |
10/19/2004
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Chapa, G., K. W. Thomas, S. M. Gordon, M. Jones, J. Raymer, J. A. Hoppin, AND M. Alavanja. Urinary Levels of 2,4-D and 3,5,6-Trichloro-2-Pyridinol for Spouses and Children of Pesticide Applicators in the Agricultural Health Study. Presented at International Society for Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-20, 2004.
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The Agricultural Health Study (AHS) is a prospective epidemiologic study of pesticide applicators and their spouses in Iowa and North Carolina. Exposure to targeted pesticides, 2,4-D or chlorpyrifos, was measured in conjunction with agricultural applications for a subset of applicators and their families. Urinary biomarker levels were measured in samples collected from applicator spouses and children immediately before and two days after a pesticide application. Questionnaires and observations of pesticide handling activities provided information about work practices, personal protective equipment (PPE) use, and hygiene practices. Forty-one spouses and 12 children provided urine samples in conjunction with one application event. Eight spouses provided additional urine samples associated with a second application event. Geometric mean and geometric standard deviation of urinary 2,4-D concentrations for forty-one spouse measures were 1.3+/-3.µg/L (range < 1-37 µg/L) in pre-application samples and were slightly higher at 1.8+/-4.6 µg/L (range < 1-59 µg/L) in post-application samples. The spouse with the highest post-application concentration used a product containing 2,4-D during the observation period. Geometric mean urinary 2,4-D concentrations for nine child measures were 1.6+/-2.2 µg/L (range < 1-5.3 µg/L) in pre-application samples and were slightly higher at 2.0+/-2.1 µg/L (range < 1-5.9 µg/L) in post-application samples. Geometric mean urinary concentrations of 3,5,6-trichloro-2-pyridinol (TCP), a chlorpyrifos metabolite, for eight spouse measures were 7.6 +/-1.8 µg/L (range 4.7-18 µg/L) in pre-application samples and were somewhat lower at 4.3+/-1.9 µg/L (range 1.1-8.3 µg/L) in post-application samples. TCP concentrations for three children ranged from 3.3 to 8.5 µg/L in pre-application samples and 1.3 to 5.3 µg/L in post-application samples. Significant associations between spouse and applicator pre- and post-application urinary 2,4-D concentrations were observed. One spouse that handled a product containing 2,4-D had the highest urinary levels. Hygiene factors such as laundering contaminated clothes did not result in significantly higher spouse urinary 2,4-D levels, but some applicator work practices, such as use of protective gloves, did appear to be related to spouse urinary 2,4-D levels.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Public Health Air Surveillance Evaluation (Phase) Air Quality Characterization for Environmental Public Health Tracking |
10/19/2004
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Watkins, T. H. Public Health Air Surveillance Evaluation (Phase) Air Quality Characterization for Environmental Public Health Tracking. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Assessing Asthmatic Children's Exposures to Toxic Air Pollutants and the Potential Inhaled Doses Using Time Activity Information and Energy Expenditure Data |
10/19/2004
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Stevens, C., R. W. Williams, AND T. R. McCurdy. Assessing Asthmatic Children's Exposures to Toxic Air Pollutants and the Potential Inhaled Doses Using Time Activity Information and Energy Expenditure Data. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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Accurately quantifying human exposures and the potential doses of various populations to environmental pollutants is critical for the U.S. Environmental Protection Agency to assess and manage human health risks. The Tampa Asthmatic Children's Study (TACS) was a pilot research study that monitored exposures to combustion related products, PM, and air toxic pollutants. Children's activities were recorded by the parents every fifteen minutes in a time activity diary, and accelerometers (Actical( R) physical activity monitor) were worn by the children to determine exertion levels and energy expenditures. The activity pattern data were collected to categorize the children's activities by their levels of energy exertion for each activity. Energy expenditures associated with these activities were used to estimate the children's ventilation rates and potential pollutant doses.
Digital accelerometer data was determined to be highly correlated (r=0.9) with the time activity diary (TAD) information for the level of activity for each participant. These results indicate that the information entered by the participants' parents in the TAD were validated by the accelerometers. Data analyses determined that the energy expenditure and the estimated ventilation rate generally increased with age, with the child's weight being the determining factor. This asthmatic cohort, on average, had reduced ventilation rates when compared to the expected or predicted ventilation rates of children without asthma. The average reductions were 45% of the recommended rates for similar children without asthma (age and/or weight). These reductions in their predicted ventilation rates were consistent with asthmatic children with severe persistent symptoms of asthma (
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Assessing Exposure Classification in the Agricultural Health Study |
10/19/2004
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Thomas, K. W., M. Dosemeci, J. Coble, G. Chapa, C. Croghan, P. A. Jones, J. A. Hoppin, D. P. Sandler, A. Blair, AND M. Alavanja. Assessing Exposure Classification in the Agricultural Health Study. Presented at Industry Farm Family Study Task Force Meeting, Philadelphia, PA, October 19, 2004.
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The Agricultural Health Study (AHS) is a prospective epidemiologic study examining cancer and non-cancer health outcomes for over 55,000 pesticide applicators and 34,000 spouses in Iowa and North Carolina. Questionnaires were used to collect information about the use of specific agricultural pesticides, work practices, and personal protective equipment. Algorithms were developed to calculate exposure intensity scores for individual applicators using literature-derived data for several important exposure factors. The AHS Pesticide Exposure Study was designed to measure applicator exposures to 2,4-D or chlorpyrifos to assess the exposure intensity algorithms. Applicators were selected into one of eight exposure scenarios based on their use of specific application methods and personal protective equipment. Dermal patch, hand wipe, and personal air samples were collected during pesticide mixing, loading, and application activities on one day. Urinary biomarker levels were measured in pre-and post-application samples. Observations and questionnaires provided information about activities that may affect exposure. A total of 108 monitoring visits were completed at 84 farms. Geometric means for the eight scenarios ranged from 7 to 70 µg/L in post application urine, 12 to 2200 µg for hand loading, 180 to 21000 µg for body loading, and 0.2 to 1.5 µg/m3 in personal air. Post-application urine concentrations and exposure intensity scores derived from observations of work activities were significantly correlated for applications of liquid 2,4-D products (Spearman r = 0.40, p < 0.0001) and applications of liquid chlorpyrifos products ( r = 0.97, p = 0.0048) but not for applications of granular chlorpyrifos products. Adjustment for the amount of active ingredient used increased the correlation between post application urine levels and exposure intensity scores for 2,4-D (r = 0.63, p < 0.0001). Dermal loadings were also significantly correlated with exposure intensity scores derived from observed work practices. In a preliminary analysis, exposure intensity scores derived from work practice information from a questionnaire completed by the pesticide applicator were similar to those derived from observations (r2 = 0.80). Correlations between exposure measures and the questionnaire-derived exposure intensity scores were similar to those from observer-derived scores.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Quantitative Pesticide Exposure Assessment of Children Living in An Agricultural Community |
10/19/2004
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Bradman, A., D. A. Whitaker, J. N. Morgan, L. S. Sheldon, M. G. Nishioka, D. Barr, R. Castorina, B. Claus, T. Mckone, M. Harnly, B. Eskenazi, AND L. Quiros. Quantitative Pesticide Exposure Assessment of Children Living in An Agricultural Community. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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In support of planning efforts for the National Children's Study, we conducted a pilot study to test field methods characterizing pesticide exposures to 20 farmworker children aged 6-24 months living in the Salinas Valley, Monterey County, California. Sample collection included dust, air, C18 press, surface wipe, toy wipe, clothing dosimeter (sock and union suits), food, spot urine, and overnight diaper urine samples. Twenty-six common agricultural and home use pesticides were measured in the environmental samples; a subset of organophosphate pesticides and permethrin were measured in food; non-specific and specific metabolites for organophsphate and other common-use pesticides were measured in urine. Four field instruments were administered, including a questionnaire, dietary recall log, home inspection, and visual activity timeline completed by the participants. The children were primarily from Mexico, Spanish speaking, had little formal schooling, and their families were of low to very low income status. Pesticides were detected more frequently in house dust than other media, with diazinon, chlorpyrifos, dacthal, and cis- and trans-permethrin detected in 95-100% of dust samples, with slightly lower detection frequencies in other media except the C18 press samples. Iprodione, malathion, and several pyrethroid pesticides commonly used as home pesticides were detected in 20-55% of the house dust samples and were detected in all media except the C18 press samples. Excluding chlorpyrifos, dust, sock, and union suit samples were correlated (Spearman r=0.32-0.58). Analytes were not detectable in any C18 press sample. Pesticide loading on sock and union suits was higher for 24 month olds compared to 6 month olds (mean ratio=2.3 and 1.8 for socks and unions suits, respectively). Organophosphate pesticides and permethrin were rarely detected in the food samples. The activity timeline, a novel, low-literacy instrument based on pictures, was successfully used by our participants. Participants were also compliant with duplicate diet and overnight diaper sample collection procedures. In all cases intensive education and demonstration was necessary to ensure that participants understood data and sample collection procedures. This presentation will summarize laboratory results for pesticides or metabolites in the environmental, food, and biological samples and will review the success of data collection instruments used with this low-income, low-literacy population.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
A Community-Based Children's Pesticide Exposure Measurement Study in Jacksonville, Florida: Results from the Aggregate Exposure Assessment |
10/20/2004
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Tulve, N. S., R. C. Fortmann, D. A. Whitaker, C. Croghan, A. Hilliard, AND L. P. Naeher. A Community-Based Children's Pesticide Exposure Measurement Study in Jacksonville, Florida: Results from the Aggregate Exposure Assessment. Presented at International Society of Exposure Analysis 14th Annual Conference, Philadelphia, PA, October 17-21, 2004.
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Young children may be more susceptible to pesticides because they are undergoing rapid development and more likely to engage in activities in which they directly contact contaminated surfaces. As a result, children may be more exposed to pesticides through normal daily activities, as compared to adults, within the home. The EPA collaborated with the Duval County Health Department (DCHD, Jacksonville, FL) and the Centers for Disease Control and Prevention on a measurement study to characterize young children's (4 to 6 years) exposures to pesticides in residential environments in Jacksonville, FL.
The study examined potential exposures of young children to a large number of organophosphate and pyrethroid pesticides. The three-tiered study design consisted of the following:
- Tier 1: Recruitment of 200 children from County health clinics, completion of a questionnaire, and collection of a urine sample from each participating child;
- Tier 2: Collection of environmental screening samples (surface wipe, transferable residue, pesticide inventory, time activity diary, urine) at the homes of approximately 25% of the enrolled children;
- Tier 3: A detailed aggregate exposure assessment (air, surface wipe, transferable residue, duplicate diet, socks, pesticide inventory, time activity diary, urine) for nine of the homes sampled in tier 2. DCHD staff collected samples in tiers 1 and 2. EPA staff performed the aggregate exposure assessment at the nine homes in tier 3.
Results from the aggregate exposure assessment will be presented. The pesticide inventories showed that pyrethroids were the most commonly applied pesticides. Environmental, personal, and biological samples, as well as activity pattern data, were collected and aggregate exposure estimates were calculated. Preliminary analyses suggest that there is a correlation between the environmental loadings of cypermethrin and the urinary metabolites, cis- and trans-DCCA. Further analysis will be presented.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Investigating Oxidation Mechanisms of Hg0 in the Free Troposphere and Its Influence on Long Range Mercury Transport |
11/16/2004
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Landis, M. S. Investigating Oxidation Mechanisms of Hg0 in the Free Troposphere and Its Influence on Long Range Mercury Transport. Presented at Fourth SETAC World Congress, Portland, OR, November 14-18, 2004.
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In 2000, the US EPA Office of Research and Development (ORD) initiated a study to evaluate the magnitude of long-range transport of mercury through the marine free troposphere to South Florida via aircraft measurements (200 to 12,000 feet). ORD funded the National Oceanic and Atmospheric Administration (NOAA) to provide a DeHavilland Twin Otter aircraft and personnel to collaborate with the collection of aerosol and trace gas measurements. One study period was conducted from January 18, through February 1, 2000 when the tropospheric winds typically transport air to South Florida from the Gulf of Mexico and the North American continent. Flights for a second study period were conducted from June 3 through June 26, 2000 when South Florida is predominantly influenced from easterly marine transport. Preliminary results from the flights indicate that mercury concentrations were significantly higher within air masses with continental influence. The Hg0 concentrations were observed to be higher below 5000 feet (2.3 +/- 0.4 ng m-3 ) than above 5000 feet (1.5 +/- 0.4 ng m-3). Conversely, the concentrations of Hg2+ were typically higher above 5000 feet (49 +/- 28 pg m-3) than below (12 +/- 7 pg m-3).
ORD subsequently initiated speciated mercury measurements at the NOAA Mauna Loa Observatory (MLO), a high altitude research station (~11,500 feet) in 2001. Observations at MLO are consistent with the aircraft results suggesting that there is a significant Hg0 oxidation mechanism at altitude. These observations are not consistent with the contemporary conceptual atmospheric mercury model that estimates the Hg0 atmospheric lifetime to be approximately 1 year. Meteorological modeling and chemical tracer results will also be presented to investigate the importance of trans-Atlantic and trans-Pacific transport of mercury species.
This work has been funded wholly or in part by the United States Environmental Protection Agency Office of Research and Development. It has been subjected to peer review and approved for publication.
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| PRESENTATION |
Modeling the Atmosphere Formation of Reactive Mercury in Florida and the Great Lakes |
12/15/2004
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Sillman, S., F. Marsik, K. I. AlWali, M. S. Landis, AND G. J. Keeler. Modeling the Atmosphere Formation of Reactive Mercury in Florida and the Great Lakes. Presented at American Geophysical Union's Fall Meeting, San Francisco, CA, December 13-17, 2004.
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Reactive mercury in the troposphere is affected by a complex mix of local emissions, global-scale transport, and gas and aqueous-phase chemistry. Here, we describe a modified version of the EPA model for urban/regional air quality (CMAQ) to include the chemistry of mercury, and model applications focusing on the Great Lakes region and on South Florida. The University of Michigan modifications to CMAQ include an integrated numerical solver for gas-phase and aqueous photochemistry, improved representation of in-cloud photolysis rates, and up-to-date reaction schemes for mercury chemistry. Reactive mercury is produced primarily by gas-phase reactions. Aqueous reactions tend to convert reactive mercury back to its elemental form, but the most important aqueous reactions (with HO2 and O2-) are problematic (Gartfeld and Jonnson, 2003). Model results suggest that gas-phase conversion from elemental to reactive mercury can lead to high concentrations of reactive mercury in the middle troposphere. Reactive mercury in the lower troposphere is removed more rapidly through both wet and dry deposition and potentially through aqueous conversion to elemental mercury. Model results are compared with a suite of comprehensive gas and aerosol measurements performed in Michigan and during aircraft measurements in S. Florida. Model results suggest that direct emission of reactive mercury contribute to atmospheric deposition in source regions.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Evaluation of Immunoassay Methods for Determination of 3,5,6-Trichloro-2-Pyridinol in Multiple Sample Media |
12/09/2004
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Chuang, J. C., J. M. Van Emon, A. W. Reed, AND N. Junod. Evaluation of Immunoassay Methods for Determination of 3,5,6-Trichloro-2-Pyridinol in Multiple Sample Media. Presented at EPA, Las Vegas EnviroExpo: Moving Towards Balance, Las Vegas, NV, December 9, 2004.
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Two enzyme-linked immunosorbent assay (ELISA) methods were evaluated for the determination of 3,5,6-trichloro-2-pyridinol (3,5,6-TCP) in multiple sample media (dust, soil, food, and urine). The dust and soil samples were analyzed by the RaPID (TM) commercial immunoassay testing kit based on antibody-coated magnetic particles. The food and urine samples were analyzed by a solid-phase 96-microwell plate immunoassay format. Methanol was used as the extraction solvent for the preparation of the dust and soil samples for analysis by both the ELISA and gas chromatography/mass spectrometry (GC/MS) procedures. Chlorobutane was used for the extraction of the urine samples for each method. The food samples were extracted with methanol for GC/MS and with acidic methanol for ELISA. The percent difference of the duplicate RaPID assays ranged from 0 to 43.4% for dust and from 0 to 47.9% for soil. The percent relative standard deviation of the 96-microwell plate triplicate assays was 15% or less for food and urine samples. Quantitative recoveries of 3,5,6-TCP were obtained for the spiked dust, soil, food and urine samples by the ELISAs ranging from 71 to 102%. Quantitative recoveries (>90%) of 3,5,6-TCP were also obtained for these samples by GC/MS. The overall method precision of these samples was within +/- 10% using the GC/MS procedure. The immunoassay and GC/MS data were highly correlated, with correlation coefficients of 0.98 for dust, 0.98 for soil, 0.93 for food and 0.98 for urine. Both ELISA methods can be used as quantitative monitoring tools for 3,5,6-TCP concentrations in dust, soil, food, and urine samples to reduce analytical costs and increase sample throughput.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Immunochemical Determination of Dioxins in Sediment Samples |
12/09/2004
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Nichkova, M., M. Chow, M. E. Koivunen, Kamita, S,G., S. J. Gee, J. C. Chuang, J. M. Van Emon, AND B. D. Hammock. Immunochemical Determination of Dioxins in Sediment Samples. Presented at EPA EnviroExpo: Moving Toward Balance, Las Vegas, NV, December 9, 2004.
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Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are considered highly toxic contaminants with the environmental monitoring of these compounds being of great importance. Immunoassay procedures such as the enzyme-linked immunosorbent assay (ELISA) may be useful as screening methods to satisfy the growing demand for rapid and low-cost analysis of these compounds. In this work, we describe the application of an immunoassay for the screening of PCDDs and PCDFs in sediments. Sample extraction and preparation methods were developed with the aim to establish the simplest, cost-effective and efficient removal of matrix interferences for the ELISA. The overall method is based on a hexane extraction; cleanup by a multilayered (H2SO4/NaOH) silica gel column followed by an activated carbon column; an organic solvent exchange with DMSO-0.01% Triton X-100, the final step being ELISA measurement. The less toxic 2,3,7-trichloro-8-methyldibenzo-p-dioxin (TMDD) was used as a surrogate standard for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The estimated theoretical method detection limit for the determination of PCDDs/PCDFs was about 20 pg TMDD equivalents per g of dry sediment. The accuracy (60-113%) and the precision (13-33% RSD) of the ELISA method were evaluated through the analysis of spiked sediment samples. Gas chromatography-high-resolution mass spectrometry (GC-HRMS) validation studies were performed using13 samples. The validation revealed that the method is suitable for Toxic Equivalent Quantity (TEQ) screening of dioxins in sediments with a method detection limit of about 100 pg TMDD g-1 sediment. The study indicated that the immunoassay screening method offers improvement in speed, sample throughput, as well as cost, in comparison to GC-HRMS analysis.
The United States Environmental Protection agency (EPA) through its Office of Research and Development funded and collaborated in the research described here under contract No.68-D 99-01 to Battelle. Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Bioavailability of Arsenic, Chromium, and Copper from Cca Contaminated Soils and Dusts |
11/12/2004
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Coppedge, E. A., S. L. Harper, K. Bradham, AND R. Keys. Bioavailability of Arsenic, Chromium, and Copper from Cca Contaminated Soils and Dusts. Presented at The Southeastern Regional Meeting of the American Chemical Society, Research Triangle Park, NC, November 10-13, 2004.
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It is estimated that 70% of single family homes have pressure-treated wood decks or porches and 14% of playground equipment uses pressure-treated wood. This popular form of wood contains chromated copper arsenate (CCA), which is an antimicrobial pesticide and is currently undergoing a rigorous risk assessment by the U.S. Environmental Protection Agency (EPA). Although manufacturers signed an agreement with EPA for voluntary cancellation of the registration of CCA-treated wood for residential uses beginning January 1, 2004, pressure-treated wood typically lasts 20 - 40 years, thus posing a potential for long-term exposure. The following projects will produce data under varying environmental conditions to help establish relationships between total concentrations and bioavailable concentrations to yield a better understanding of the absorbed dose of toxic elements. The bioavailability approach seeks to reduce uncertainty of total concentration analyses, which may over or under estimate health hazard, provide inaccurate risk assessments, and inappropriate risk-reduction expenses.
EPA's National Exposure Research Laboratory (NERL) is collaborating with the U.S. Department of Housing and Urban Development in the nationwide "American Healthy Homes Survey", which will provide data from a national cross-section of residential soils collected near CCA-treated wood outside homes and indoor house dusts. NERL is also collaborating with EPA's National Risk Management Research Laboratory (NRMRL) on a research project evaluating the effectiveness of coatings in reducing dislodgeable arsenic (As) from CCA-treated wood. NERL's main role in the project is to use bioassays, including earthworms and lettuce, to investigate the bioavailability of As, Chromium (Cr), and Copper (Cu) in the soil below coated CCA mini decks. Results to date show that total arsenic in the mini decks field control soils are below background concentrations. The results to date for both projects will be presented.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Analytical Methods Developed for the Children's Total Exposures to Persistent Pesticides and Other Persistent Organic Pollutants (Ctepp) Study |
11/12/2004
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MedinaVera, M., M. K. Morgan, J. M. Van Emon, A. B. Lindstrom, E. M. Ulrich, AND J. N. Morgan. Analytical Methods Developed for the Children's Total Exposures to Persistent Pesticides and Other Persistent Organic Pollutants (Ctepp) Study. Presented at The Southeastern Regional Meeting of the American Chemical Society, Research Triangle Park, NC, November 10-13, 2004.
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The Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) study was designed by the U.S. EPA to collect data on young children's exposures to pesticides and other pollutants in their everyday environments in support of the Food Quality Protection Act of 1996. Participants were recruited randomly from selected homes and day care centers in 12 North Carolina and Ohio counties. Monitoring was performed over a 48-h period at the children's homes and/or day care centers. Samples that were collected included diet, water, air, urine, dust, soil, and surface wipes. Analytical methods were developed for some of the pollutants (e.g. perfluorinated acids, cis-Permethrin, Chlorpyrifos, 3,5,6-Trichloro-2-pyridinol) in media such as house dust and food while the study was on-going. These included screening methods (i.e., immunoassays) and quantitative analytical techniques (i.e., LC/MS/MS and chiral separations). These methods represent a significant step forward in reducing uncertainties in assessing children's exposures to these pollutants in their everyday surroundings. This work was a collaborative effort with several divisions (Cincinnati, OH; Las Vegas, NV and Research Triangle Park, NC) located in the National Exposure Research Laboratory. A brief discussion on the methods that were developed will be presented.
This is an abstract of a proposed presentation and does not necessarily reflect the United States Environmental Protection Agency (EPA) policy. The actual presentation has not been peer reviewed by EPA. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Pilot Study: the Tampa Asthmatic Children's Study (Tacs) |
12/03/2004
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Williams, R. W. Pilot Study: the Tampa Asthmatic Children's Study (Tacs). Presented at The National Children's Study Pilot Study Review Workshop, Research Triangle Park, NC, December 3, 2004.
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The Tampa Asthmatic Children's Study (TACS) was a pilot research study that focused on developing and evaluating air pollution exposure assessment methods and participant recruiting tools for children in the age range of 1-5 years old. The pilot study focused on (a) simple, cost-effective methods for assessing environmental exposures relevant to asthma and (b) the development of techniques for the early assessment of asthma-related health outcomes. The study was designed to evaluate simple exposure measurement methods that might be used in the National Children's Study (NCS) and other human exposure studies. The TACS was a nine child pilot study conducted in the fall of 2002. Young children (<6 years of age) were recruited and enrolled in this study which focused upon collecting exposure assessment data relative to combustion related products (CRPs). Field data collection was completed in 2002. The database validation, analyses, and reporting are in various stages of completion. Data from chemical analyses that are currently being completed will be used to evaluate the specific influence of various air pollutant sources on the children's exposure. The Florida Department of the Environment, Hillsborough County, and the study participants have been briefed on preliminary exposure data from the study. Data will be report in an EPA Research Report on "Lessons Learned" and in journal manuscripts currently being developed.
Although this work was reviewed by EPA and approved for publication, it may not necessary reflect official Agency policy.
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| PRESENTATION |
Gas Particle Partitioning of Chlordanes in Coupled Indoor/Outdoor Air Samples from Three U.S. Cities |
11/18/2004
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Offenberg, J., Y. Y. Naumova, S. Eisenreich, AND B. Turpin. Gas Particle Partitioning of Chlordanes in Coupled Indoor/Outdoor Air Samples from Three U.S. Cities. Presented at Fourth SETAC World Congress, Portland, OR, November 14-18, 2004.
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Concentrations of six Chlordane species (trans-chlordane, cis-chlordane, trans-nonachlor, cis-nonachlor, oxychlordane and MC5) were measured indoors and outdoors at 157 non-smoking residences in three urban areas during June 1999-May 2000. These measurements were performed on a subset of samples collected within the Relationship of Indoor, Outdoor, and Personal Air study (RIOPA). The objective of the study was to evaluate the hypothesis that outdoor air pollution strongly contributes to indoor air pollution. Forty-eight hour integrated samples were collected from homes in Los Angeles County, CA, Houston, TX, and Elizabeth, NJ. Both particle bound (PM2.5; quartz fiber filter) and vapor phase (PUF adsorbant) chlordane concentrations were separately measured by GC/EI-MS after solvent extraction. The measured partition coefficients of Chlordanes were correlated with the compounds' sub-cooled liquid vapor pressure. Measured partition coefficients varied by two orders of magnitude for any value of vapor pressure. These variations in gas/particle partitioning of Chlordanes are related to the aerosol characteristics and sampling conditions. Multiple linear regression analysis (MLR), which included temperature corrected vapor pressure, fOC and fEC as independent variables, as well as corresponding interaction terms, explains up to 44% of the variability of the partition coefficients. This is higher than the explained variance when vapor pressure is used as a single parameter. The relative importance of each variable for prediction of partition coefficients in both indoor and outdoor air will be discussed. Further comparisons of octanol-air partition coefficient with vapor pressure will also be presented.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect Agency policy.
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| PRESENTATION |
Children's Exposures to Endocrine Disrupting Chemicals |
12/14/2004
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FORTMANN, R. C., M. K. MORGAN, AND N. S. TULVE. Children's Exposures to Endocrine Disrupting Chemicals. Presented at EDC Program Review, Research Triangle Park, NC, December 13 - 15, 2004.
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EPA is committed to protecting children's health by identifying, assessing, and reducing the risks from chemicals present in the air they breathe, food they eat, water they drink, and surfaces they touch. The Agency is committed to understanding the extent of children's exposures to EDCs and the factors that affect their exposures. Two large children's exposure studies have been designed to collect data that will improve our understanding of young childrens exposures to chemicals that are potential EDCs. The two studies address exposures of children from birth to approximately 5 years of age, include exposures in residential and child care settings, and address a number of different classes of chemicals. The Childrens Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) study (completed in 2002) is one of the largest aggregate exposure studies of preschool children in the U.S. In this landmark study, the exposures of about 260 children (ages 2 to 5 years) to persistent and non-persistent organic chemicals were measured in homes and child care centers in North Carolina and Ohio. The targeted chemicals included polychlorinated biphenyls (PCBs), organochlorine pesticides (OCs), pyrethroid pesticides, alkyl phenols, and phthalates. Measurements were performed to determine the important sources, pathways, and routes of exposure for these preschool children. Results of the study showed that there were low levels of many chemicals, including potential EDCs (e.g. chlordane, bisphenol-A), in both the homes and child care centers. Bisphenol-A, for example, was measured in 65% of the indoor air samples Chlordane was detected in over 85% of the indoor air and dust samples collected in the study. Median concentrations of gamma-chlordane, as an example, were 1.5 ng/m3 in indoor air and 31 ng/g in dust samples collected in homes and 0.78 ng/m3 in indoor air and 67 ng/g in dust samples collected in child care centers in North Carolina. Dietary ingestion was shown to be the most important route of exposure for many chemicals, including bisphenol-A. The CTEPP data will be complemented by data collected in the Children's Environmental Exposure Research Study (CHEERS), to be initiated in the spring of 2005. Data will be collected in CHEERS for children under three years of age, filling a critical data gap for young children. Measurements will be performed for polybrominated diphenyl ethers (PBDEs), phthalates, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and a large suite of synthetic pyrethroid pesticides. This large children's exposure study will involve repeated visits to the home of each study child up to six times over a two-year period in order to evaluate the impact of the children's age and activities on their exposures. Like CTEPP, data will be analyzed to determine the extent of exposure, the important routes of exposure, and the factors that have the greatest impact on children's exposures to chemicals in their homes.
This poster does not necessarily reflect EPA policy. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Evaluation of Exposure Measurement Methods and Approaches for the National Children's Study |
12/03/2004
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THOMAS, K. W., Y. HU, AND J. RAYMER. Evaluation of Exposure Measurement Methods and Approaches for the National Children's Study. Presented at NCS Pilot Study Meeting, Research Triangle Park, NC, December 03, 2004.
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Several hypotheses have been proposed for the National Children's Study to examine the role of environmental exposures to chemical pollutants in health outcomes including asthma and impaired neurobehaviorial or neurocognitive function. To address these hypotheses, it will be necessary to assess exposures to a range of chemical pollutants at different life stages through the use of survey tools and biological and environmental measurement methods. The purpose of this work was to survey the literature to obtain and synthesize existing information about personal and environmental measurement methods and approaches, exposure questionnaire and diary methods, and to provide exposure data from pervious human exposure studies that are most relevant to the National Children's Study. This work also examined the relative strengths and weaknesses of existing methodology for chemical exposure measurement in a longitudinal study of children.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Assessing Exposures to Mobile Source Air Toxic Emissions for Populations Living Near Roadways |
12/01/2004
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BALDAUF, R. W., C. BAILEY, AND J. P. WEINSTEIN. Assessing Exposures to Mobile Source Air Toxic Emissions for Populations Living Near Roadways. Presented at CRC Mobile Source Air Toxics Workshop, Phoenix, AZ, November 30 - December 02, 2004.
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A growing number of epidemiological studies have identified an increase in occurrence of adverse health effects for populations living near major roads. However, the biological mechanism(s) leading to the adverse effects have not been identified. Limitations in exposure assessment have resulted in a need to evaluate and improve methods of predicting exposures in the near road environment. Questions remain on the spatial extent of the zone of influence of the road, and the factors affecting concentration variability including traffic volume, vehicle fleet mix, and fleet operating characteristics. Federal agencies have also been under increasing pressure to evaluate potential air quality and health impacts from roadway construction.
The Traffic-Related EXposure (T-REX) Study will provide data to characterize the temporal and spatial variability in pollutant concentrations in the near road environment. Air toxics measurements will be collected along 500 meter transects away from major roads with traffic volumes in excess of 100,000 vehicles per day. Air measurements include volatile organic compounds (benzene, toluene, ethylbenzene, zylenes), particulate matter (mass, number, elemental/organic carbon, semi-volatile organic carbon), and regulated gases (CO, CO2, NOx, and O3). Air quality measurements will be collected at fixed site locations, in a mobile monitoring vehicle, and at a fixed site trailer also equipped with meteorological monitoring devices (wind speed, wind direction, temperature, humidity and mixing height). In addition to ambient air quality measurements, monitors will be placed directly outside and inside buildings adjacent to the major roadways to determine contaminant infiltration. Air quality monitoring will emphasize continuous and near continuous measurement techniques. Tracer gas will also be released near the roadway to measure atmospheric dilution during the measurement period. Video recordings will be used to assess roadway activity during the collection of air quality measurements. Results of the study will provide detailed data to evaluate and improve exposure and air quality models supporting epidemiologic studies and assessments of transportation system impacts.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Persistent Perfluorinated Compounds in the Environment: A New Challenge for the U.S. Environmental Protection Agency |
12/02/2004
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LINDSTROM, A. B. AND M. J. STRYNAR. Persistent Perfluorinated Compounds in the Environment: A New Challenge for the U.S. Environmental Protection Agency. Presented at Tokyo American Center, Embassy of the United States, Tokyo, JAPAN, December 02, 2004.
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There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
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| PRESENTATION |
Evaluation of Disposable Diapers for Quantative Measurements of Pesticide Metabolites and Creatinine in Urine Samples |
12/03/2004
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FORTMANN, R. C. Evaluation of Disposable Diapers for Quantative Measurements of Pesticide Metabolites and Creatinine in Urine Samples. Presented at NCS Pilot Study Review, Research Triangle Park, NC, December 03, 2004.
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This project consisted of a laboratory study to evaluate an extraction and analysis method for quantifying biomarkers of pesticide exposure and creatinine in urine samples collected with commercially-available disposable diapers. For large exposure studies, such as the National Children's Study (NCS), it is highly desirable to identify a low burden, low-cost method for collection of urine from infants and very young children. Disposable diapers that contain polyacrylate fibers or granules can be used to collect the urine samples if the pesticide metabolites can be quantitatively recovered from the diaper materials. The testing was performed in two phases. An initial set of tests was performed to evaluate the feasibility of the proposed solvent extraction and gas chromatography/mass spectrometry (GC/MS) analysis method. After demonstrating that the proposed method was feasible, a second set of tests was performed to document the performance of the method for metabolites of chlorpyrifos, diazinon, and synthetic pyrethroid pesticides. Laboratory testing has been completed. The testing showed that a single derivatization method could not be used for both the pyrethroid metabolites and the metabolites of chlorpyrifos and diazinon. The limit of detection for the method was 0.1 to 0.4 ng/mL for the ten metabolites that were tested. The efficiencies of extraction of the metabolites from the diapers ranged from 58% for cis-3-(2,2-dimethylvinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (DMCA), a metabolite of synthetic pyrethroid pesticides to 102 % for 3,5,6-trichloro-2-pyridinol (TCPy), a metabolite of chlorpyrifos. The extraction efficiency was greater than 70% for eight of the 10 metabolites tested. The average extraction efficiency was 108% for creatinine. The results show that the method will be suitable for use in exposure measurement studies.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
Demonstration of Low Cost, Low Burden Exposure Monitoring Strategies Birth Cohort |
12/03/2004
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FORTMANN, R. C. Demonstration of Low Cost, Low Burden Exposure Monitoring Strategies Birth Cohort. Presented at NCS Pilot Study Review, Research Triangle Park, NC, December 03, 2004.
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This study was designed to develop and demonstrate relevant, low cost, low burden monitoring strategies that can be used in a longitudinal epidemiological study that focuses on pregnant women and young children. The focus of this study was on (1) recruiting and retaining participants (children and their caretakers) in a longitudinal exposure study and (2) demonstrating the feasibility of measurement strategies that use remote employment of readily available, easy to use, state-of-the-art methods, instruments, and/or techniques for assessing human exposures to environmental contaminants. The monitoring strategies involved mailing sampling kits to study participants with instructions for collecting biological samples (e.g., urine, breast milk, and hair) and environmental samples (e.g., water, house dust, surface wipes and personal air samples). After collection, participants packaged and shipped the samples back to the laboratory. Participants also completed an on-line questionnaire that collected information on contaminant sources and participant activities at the time of sample collection. The study has been completed. Results of the study demonstrated high retention rates over the one-year sample collection period. Compliance with sample collection protocols was very good and return rates were high for most sample types. Return of urine samples collected with diapers or as first morning voids was very good. As expected, participants had difficulty collecting samples using more complex methods, such as a badge sampler for volatile organic compounds. Considerable information was generated that favorably supports the strategy of remote sample collection by study participants. Lessons learned in the study will be important in developing the sample collection protocols for the National Children's Study.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
(Presented at Morioka, Japan) Persistent Perfluorinated Compounds in the Environment: A Brief Introduction to This Important New Class of Pollutants |
12/16/2004
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LINDSTROM, A. B. AND M. J. STRYNAR. (Presented at Morioka, Japan) Persistent Perfluorinated Compounds in the Environment: A Brief Introduction to This Important New Class of Pollutants. Presented at Research Institute for Environmental Sciences and Public Health of Iwate, Morioka, JAPAN, December 16, 2004.
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PowerPoint presentation summarizing method development research involving the persistent perfluorinated organic compounds. Review of data indicating widespread distribution of these materials and the potential for toxicity.
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| PRESENTATION |
(Presented at Tsukiji, Chuo-Ku, Japan) Persistent Perfluorinated Compounds in the Environment: A Brief Introduction to This Important New Class of Pollutants |
12/21/2004
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LINDSTROM, A. B. AND M. J. STRYNAR. (Presented at Tsukiji, Chuo-Ku, Japan) Persistent Perfluorinated Compounds in the Environment: A Brief Introduction to This Important New Class of Pollutants. Presented at National Cancer Research Center for Cancer Prevention and Screening Epidemiology and Prevention Division, Tsukiji, Chuo-ku, JAPAN, December 21, 2004.
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PowerPoint presentation summarizing method development research involving the persistent perfluorinated organic compounds. Review of data indicating widespread distribution of these materials and the potential for toxicity.
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| PRESENTATION |
(Presented at Tsukuba, Japan) Persistent Perfluorinated Organic Compounds Method Development Research at the U.S. Environmental Protection Agency |
12/09/2004
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LINDSTROM, A. B. AND M. J. STRYNAR. (Presented at Tsukuba, Japan) Persistent Perfluorinated Organic Compounds Method Development Research at the U.S. Environmental Protection Agency. Presented at National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan, JAPAN, December 09, 2004.
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PowerPoint presentation summarizing method development research involving the persistent perfluorinated organic compounds. Review of data indicating widespread distribution of these materials and the potential for toxicity.
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| PRESENTATION |
Identifying High Priority Exposure Research Supporting the EPA Asbestos Action Plan |
12/09/2004
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VALLERO, D. A., T. L. CONNER, AND R. HIGHSMITH. Identifying High Priority Exposure Research Supporting the EPA Asbestos Action Plan. Presented at Asbestos Site Evaluation Communication and Cleanup, Tampa, FL, December 08 - 10, 2004.
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The EPA Asbestos Action Plan outlines areas, including two exposure assessment areas, where research is needed to reduce uncertainties in current asbestos risk assessments. Scientists from the National Exposure Research Laboratory (NERL) recently conducted survey and literature searches to identify potential data/methods/research gaps and areas of uncertainty in conducting asbestos exposure assessments. The Regional Asbestos Coordinators and representatives of EPAs Asbestos Coordination Team were asked to complete a relatively simple survey where they would identify the most important asbestos exposure scenarios they routinely address. They were also asked to identify the sampling and analytical methods used to conduct these asbestos scenario assessments and to include any problems they encounter in their scenario assessments. The results of these surveys and queries have been summarized and will be presented during the general conference session, with opportunities for additional discussion and clarification of these reported issues occurring in the subsequent breakout sessions. During the breakout group discussions, EPAs Office of Research and Development will work with the participants to refine and clarify the research issues and to gain consensus regarding the overall highest priority exposure research needs. During a final breakout session, NERL will present a summary of the workshop discussions and proposals, to include a draft prioritized list of exposure research needs for review and discussion. Through this iterative gap analysis process, ORD and the members of the EPA Asbestos Coordination Team will develop a final list of priority asbestos exposure research needs that can be used as the basis for ORDs asbestos exposure research plan.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.
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| PRESENTATION |
The Use of Time/Activity Diaries and Computer-Assisted Reporting in Exposure Study |
12/10/2004
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TULVE, N. S., R. C. FORTMANN, T. R. MCCURDY, C. D. STEVENS, D. A. WHITAKER, AND R. W. WILLIAMS. The Use of Time/Activity Diaries and Computer-Assisted Reporting in Exposure Study. Presented at National Children's Study Workshop, Washington, DC, December 09 - 10, 2004.
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There is no abstract for this product. If further informaiton is requested, please refere to the bibliographic citation and contact the person listed under contact field.
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| PRESENTATION |
US EPA Research Activities to Characterize Children's Environmental Exposures. |
12/16/2004
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COHEN-HUBAL, E. A. US EPA Research Activities to Characterize Children's Environmental Exposures. Presented at Environmental Research for the Future - US EPA, Region 7, Kansas City, KS, December 16, 2004.
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There is no abstract for this product. If further informaiton is requested, please refere to the bibliographic citation and contact the person listed under contact field.
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| PRESENTATION |
Use of the Aerodynamic Particle Sizer to Measure PM-Coarse |
02/09/2004
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PETERS, T. AND R. W. VANDERPOOL. Use of the Aerodynamic Particle Sizer to Measure PM-Coarse. Presented at American Association of Aerosol Research, Atlanta, GA, February 07 - 11, 2005.
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The aerodynamic particle sizer (APS 3321, TSI, Inc.) measures particle size distributions from 0.5 µm to 20 µm by determining the time-of-flight of individual particles in an accelerating flow field. A complete particle size distribution may be determined in a matter of seconds, making the APS ideal for assessing rapid fluctuations in atmospheric PM-coarse. Recent laboratory tests show that the APS 3321 can sample PM-coarse-sized particles with near 100% efficiency if they are solid; however, this efficiency becomes substantially lower for liquid droplets.
This work compared PM-coarse measurements made with 24-hr, filter-based PM samplers to that measured with the APS. Two APS 3321 instruments with PM-10 and PM-2.5 samplers were deployed in four field campaigns in three U.S. cities: Gary, IN, Riverside, CA, and Phoenix, AZ. To collect representative aerosol samples, each APS sampled isokinetically from the downtubes of a standard 16.7-Lpm, FRM PM-10 inlet. In addition to comparing 24-hr measurements, the APS data were investigated to observe trends in temporal and size variability of the PM-coarse aerosol.
Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy. Mention of trade names of commercial products does not constitute endorsement or recommendation for use.
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| PRESENTATION |
Environmental Chamber Studies of Mercury Reactions in the Atmosphere |
12/15/2004
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Sumner, A. L., C. W. Spicer, J. Satola, R. Mangaraj, M. S. Landis, R. K. STEVENS, AND T. D. Atkeson. Environmental Chamber Studies of Mercury Reactions in the Atmosphere. Presented at American Geophysical Union's Fall Meeting, San Francisco, CA, December 13-17, 2004.
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Mercury is released into the environment through both natural and anthropogenic pathways. The cycling and fate of mercury in atmospheric, soil, and water ecosystems is impacted by various factors, including chemical transformation and transport. An understanding of these processes is critical for predicting the impact of mercury emission controls and future mercury concentrations. The chemical transformations of elemental mercury in the atmosphere were studied to determine the role of atmospheric chemistry in the mercury cycle. The rates of the gas phase reactions of elemental mercury with molecular bromine, chlorine, and fluorine, the atomic halogens, BrO, ClO, ozone, and the nitrate radical were studied at room temperature in a 17.3 m3 environmental chamber. The fate of elemental mercury resulting from these chemical reactions was addressed by measurement of reactive gaseous mercury, article-phase mercury, and reactive mercury lost to the chamber surfaces during the experiments. The implications of these chemical reactions and others studied in environmental chambers for the cycling of elemental atmospheric mercury will be discussed.
This work has been funded wholly or in part by the United States Environmental Protection Agency Office of Research and Development. It has been subjected to peer review and approved for publication.
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| PRESENTATION |
GIS-Modeled Indicators of Mobile Source Emissions and Adverse Health Effects Among Children in El Paso, Texas, USA |
08/02/2004
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NEAS, L. M., M. GONZALES, S. MUKERJEE, L. SMITH, E. R. SVENDSEN, M. ROSS, D. B. WALSH, S. W. RHONEY, G. ANDREWS, AND H. A. OZKAYNAK. GIS-Modeled Indicators of Mobile Source Emissions and Adverse Health Effects Among Children in El Paso, Texas, USA. Presented at 16th Conference on International Society for Environmental Epidemiology, New York , NY, August 01 - 04, 2004.
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The El Paso Children's Health Study has been a major collaborative effort by NHEERL and NERL scientists to examine the role of mobile source emissions in the development of allergies and asthma among 4th and 5th grade children in El Paso, TX. The purpose of this study was to determine if exposures to gaseous air toxics and particulate matter from mobile and other urban sources are associated with increased incidence of respiratory health effects in children. Intra-urban gradients of exposure and possible respiratory outcomes were evaluated.
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| PRESENTATION |
Monitoring Exposure to Point-Source Aerosolized Contaminants: Can We Continue to Assume They Are Well-Mixed? |
04/20/2004
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RichmondBryant, J., A. D. Eisner, AND R. W. Wiener. Monitoring Exposure to Point-Source Aerosolized Contaminants: Can We Continue to Assume They Are Well-Mixed? Presented at Symposium on Air Quality Measurement Methods and Technology - 2004, Raleigh Durham, NC, April 19-22, 2004.
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Monitoring of aerosols is typically regulated over 3-hour to diurnal time scales for outdoor concentration levels and 15-minute to 8-hour scales indoors. At these scales, concentration is assumed to be well mixed with little spatia-temporal variability around the sampler. Less attention has been given to the potential for acute exposure to contaminants during the initial minutes after a point-source release, where pointwise concentrations may greatly exceed the well mixed conditions. Here, we seek to demonstrate that the commonl used well mixed assumption is flawed in the first minutes after the contaminant is released, because pointwise concentration levels are initially highly non-uniform and are mitigated by the presence of obstacles and turbulent structuresin the vicinity of the samplers. This assumption is examined by releasing 1 mm aerosols in a test room with HEPA-filter ventilation by varying controlled conditions of ventilation rate (0.25 m/s and 0.5 m/s), room furnishing (furnished vs. unfurnished), a release locations (at the inlet vent, under the desk). For each experiment, aerosol concentrations are measured simultaneously at nine locations using a combination of spectrometry and nephelometry. Additionally, air velocity and turbulence intensity are measured with hot wire anemometry at each of the aerosol sampling points to discern any correlation between the pattern of aerosol dispersion and the airflow characteristics. Complimentary computational fluid dynamics simulations are performed to validate the experiments and to provide detailed pictaures of the velocity profiles and particle trajectories. The experimental and numerical results cooroborate the hypothesis. For both release locations, a completely well mixed condition has not occurred five minutes after the release, and aerosol dispersion is dictated by the turbulent airflow pattern. This information may be used to develop new instrumentation for first responders to detect spatial concentration patterns upon entering a room in which a hazardous substance has just been aerosolized.
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| PUBLISHED REPORT |
Identification of Time-Integrated Sampling and Measurement Techniques to Support Human Exposure Studies |
05/01/2004
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McKinney, J. D., S. N. Hern, AND G. L. Robertson. Identification of Time-Integrated Sampling and Measurement Techniques to Support Human Exposure Studies. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-04/043 (NTIS PB2004-105639), 2004.
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Accurate exposure classification tools are required to link exposure with health effects in epidemiological studies. Long-term, time-integrated exposure measures would be desirable to address the problem of developing appropriate residential childhood exposure classifications. Screening techniques are also of interest that could focus attention on the most highly exposed (to indicator compounds) populations for which costly multiroute, multimedia monitoring would be most informative. This report presents the results of a literature review that was designed to investigate and/or evaluate methods used in classifying exposure, both long-term, time-integrated and screening methods for assessing exposures to relatively short half-life contaminants.
The information in this document has been funded and managed by the United States Environmental Protection Agency under Contract 68-D-99-012 to Research Triangle Institute. It has been subjected to the Agency's peer and administrative review and has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PUBLISHED REPORT |
Demonstration of Low Cost Burden, Exposure Monitoring Strategies for Use in Longitudinal Cohort Studies Volume I Final Report and Volume II Appendices |
09/02/2004
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Rench, J., J. Raymer, L. Thalji, M. Spruill, C. A. Salmons, L. Michael, M. J. Pecha, E. Dean, G. G. Akland, AND R. C. Fortmann. Demonstration of Low Cost Burden, Exposure Monitoring Strategies for Use in Longitudinal Cohort Studies Volume I Final Report and Volume II Appendices. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-04/109 (NTIS PB2006-101283), 2004.
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The Federal Government is currently planning a large, prospective birth cohort study known as the National Children's Study that will potentially involve 100,000 children and their families. The observation period will start as close to conception as possible and will continue for 20 years after birth. Given the magnitude and expense of such a large study, sample collection methods that are amenable to acquisition of samples exclusively by the participants themselves followed by direct shipment to the analysis laboratory present a cost-effective alternative to technician-based sampling procedures. In this pilot study, the ability of participants in three age cohorts to collect environmental and biological samples according to prescribed protocols was evaluated. The cohorts consisted of parents and their children in the ages of 0-1 year, 3-5 years, and 6-8 years old. Biological and environmental samples collected during the study included urine, hair, saliva, breast milk, duplicate diet, tap water, vacuum cleaner dust, floor surface dust wipes, air samples, cotton sock dosimeters, and humidity/temperature measurements. Sample collection instructions and materials were prepared, subjected to evaluation and modification using a test population, and shipped to participants over a 12-month period. Participants were requested to collect the samples, complete questionnaires, and return the samples to the laboratory within defined time periods. Upon receipt at the laboratory, the condition of the samples was assessed by visual inspection and the details of the receipt and evaluation were logged into a computer database; queries were subsequently used to assess compliance. In some cases, chemical analysis was used to further evaluate sample integrity.
The demonstration studies generated considerable information that favorably supports sample collection by study participants and remote data collection via the web, although the studies brought forward a number of issues that can impact a large-scale study such as the NCS. Completion rates for the different on-line surveys were 73% or better. For a relatively complex survey including pesticide use, the response rate was 92%. There was a 96% response rate for completion of a time/activity diary related to the participant child's exposure to pesticides in the home. Participant compliance with sample collection instructions appeared to be good for most sample types. One hundred percent of the hair samples and vacuum cleaner dust samples, for example, were considered to be acceptable. Acceptability rates were greater than 85% for breast milk, urine and food. But the number of acceptable beverage (diet) and tap water samples was lower due to return of leaking containers. The number of acceptable samples was substantially lower for the more complex sampling methods. All of the VOC air sampling badges were returned to the laboratory, but only 56% of the samples were determined to be acceptable. Although an instructional video was included with the badge, the participants found the sample collection method to be too complex. Samples were generally returned in a timely manner, in compliance with the instructions. Results of this project are very encouraging, indicating that remote data collection by study participants is feasible. Results can be used to develop strategies that will maximize completeness of sample collection while minimizing participant burden and study costs.
The U.S. Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under Contract Number 68-D-99-012 to RTI International. It has been subjected to the Agency's peer and administrative review and has been apprpoved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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| PUBLISHED REPORT |
A Pilot Study of Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (Ctepp) |
10/25/2004
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Morgan, M. K., L. S. Sheldon, C. Croghan, J. C. Chuang, C. Lyu, N. K. Wilson, R. A. Lordo, M. C. Brinkman, N. Morse, Y. L. Chou, C. Hamiltin, J. K. Finegold, K. Hand, AND S. M. Gordon. A Pilot Study of Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (Ctepp). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-04/193 (NTIS PB2006-101286), 2005.
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The Pilot Study of Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) investigated the aggregate exposures of 257 preschool children and their primary adult caregivers to pollutants commonly detected in their everyday environments. The target compounds include organophosphate (OP) pesticides, OP metabolites, organochlorine (OC) pesticides, pyrethroid pesticides and metabolites, acid herbicides, polycyclic aromatic hydrocarbons (PAH), phthalates, phenols, polychlorinated biphenyls (PCB), PAH metabolites, and atrazine. Some of the target compounds are persistent indoors and sometimes outdoors, so that very low levels may exist in the children's surroundings and provide a source of non-acute exposure. The primary purposes of the research were to increase the understanding of children's exposures to persistent and non-persistent organic pollutants, and to gain information on the various activities, environmental media, and pollutant characteristics that may influence children's exposures. The overall objectives were to measure the aggregate exposures of approximately 260 preschool children and their adult caregivers to low levels of a suite of pesticides and other organic pollutants that the children may encounter in their everyday environments and to apportion the routes of exposure and estimate the relative contributions of each route. Within these objectives, four major, specific goals for the CTEPP study were accomplished in this report. These goals were: (1) to measure the concentrations of the target pollutants in multimedia samples collected at the homes and at day care centers of preschool children in six North Carolina (NC) counties and six Ohio (OH) counties, (2) to determine the distributions of child characteristics, activities, and locations that contributed to their exposures, (3) to estimate the aggregate exposures of the preschool children to these pollutants that they may encounter in their everyday environments, and (4) to apportion the routes of exposure. Results will also be used to identify important hypotheses to be tested in future research.
A two-state sampling plan was used to select and recruit study participants. In each state, a total of four urban and two rural counties were randomly selected. The counties were located in three distinct geographical regions of each state. These regions were the mountains, the Piedmont, and the coastal plain of NC, and the northern, central, and southern regions of OH. Dual sampling frames (the day care and the telephone components) were used in each state. To recruit participants in households whose children attended child day care centers, 13 centers in the six NC counties and 16 centers in the six OH counties were selected using probability sampling. Children were then selected randomly from classrooms having children in the eligible age group of two to five years, and their participation was recruited through their parents. To recruit participants in households whose children did not attend child day care centers, list-assisted, random digit dialing telephone sampling in the selected counties was used.
The calculated response rates in NC were 53% for day care centers and 50% for day care parents. In OH these response rates were 57% for OH day care centers and 31% for OH day care parents. The calculated response rate for the telephone sample was 58% in NC and 57% in OH. In NC, children and their caregivers in 130 households participated in the study; in OH, 127 households participated. Approximately half of the children in each state attended child day care centers (63 in NC and 58 in OH). About 84% of the NC participants and 87% of the OH participants lived in urban locations. Low-income households, classified according to federal guidelines for the Women, Infants, and Children (WIC) program (185% of the federal poverty level), comprised 46% of the sampled households in NC and 38% of those in OH.
More than 5,000 discrete personal and environmental samples, including quality control samples, were collected in each state and analyzed. Additionally, house/building characteristics observation surveys, pre- and post-monitoring questionnaires, day care food menus, and detailed child/adult time-activity and food diaries provided ancillary information necessary to estimate aggregate exposures and to aid in interpretation of the CTEPP data.
Field sampling for the day care component took place over a 48-h period at each child's day care center and simultaneously at his/her home. Field sampling for the telephone component took place over a 48-h period at each participant's home. Environmental samples included indoor and outdoor air, outdoor play area soil, indoor floor dust (carpet dust) or if no carpet, hard floor surface wipes, and household/day care drinking water. Personal samples included duplicate diet, hand wipes, and urine. If a pesticide had been applied in the seven days prior to or during sampling, transferable residues, hard floor surface wipes and food preparation surface wipes were also collected. Approximately 10% of the children were videotaped for about 2 h at their homes in OH during sampling to supplement and validate the activity diaries and observations.
All samples, including quality control samples, were extracted, and then analyzed by gas chromatography/mass spectrometry for over 50 target compounds. These compounds included two organopnospnorus (OP) pesticides,two OP metabolites, ten organochlorine (OC) pesticides, one pyrethroid metabolite, three acid herbicides, nine polycyclic aromatic hydrocarbons (PAHs), six PAH metabolites, two phthalates, three phenols, 17 polychlorinated biphenyls (PCBs), and atrazine. These compounds, with the exception of atrazine, PAH metabolites and pyrethroid metabolites, were analyzed in the environmental and personal samples. Atrazine was analyzed only in drinking water samples. Only one OP metabolite, 3,5,6-trichloro-2-pyridinol (3,5,6-TCP), was analyzed in the NC environmental and personal samples; both 2-isopropyl-6-methyl-4-pyrimidinol (IMP) and 3,5,6-TCP were measured in the OH samples. In the NC urine samples, two OP metabolites; IMP and 3,5,6-TCP; 2,4-dichlorophenoxyacetic acid (2,4-D), two hydroxy PAHs: 1-hydroxybenz[a]anthracene and 3-hydroxychrysene; and pentachlorophenol were analyzed. In the OH urine samples, these same metabolites and/or parent compounds were analyzed, in addition to five hydroxy PAHs (1-hydroxypyrene, 3-hydroxybenz[a]anthracene, 3-hydroxybenzo[a]pyrene, 6-hydroxychrysene, and 6-hydroxyindeno[l,2,3-cd]pyrene) and 3-phenoxybenzoic acid (3-PBA).
Two similarly formatted CTEPP databases were developed, one for the NC study and one for the OH study. Each database contained questionnaire data, analytical data, and metadata, and provided sufficient documentation to allow the data to be understood by a diverse set of users. Descriptive statistics were calculated for sample size, mean, standard deviation, percentage detected, minimum and maximum reported values, and selected percentiles (25th, 50th, 75th , and 95th ). The distributions of participant characteristics, activities, and locations that are important for exposure were quantified, based on the questionnaire data. Potential exposures and potential absorbed doses were estimated for selected target compounds, based on the percentage of the samples that had detectable levels of these compounds, the measured concentrations, the participants' activity patterns, and assumed physiological parameters. Statistical analyses to meet the four goals of the study were performed on log-transformed data, using analysis of variance (ANOVA) models. The data summaries presented in this report represent only the children and their primary caregivers in NC and OH who participated in this study.
The information in this document has been funded wholly by the United States Environmental Protection Agency under EPA contract number 68-D-99-011 to Battelle Memorial Institute. It has been subjected to the Agency's peer and administrative review and has been approved for publication as an EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
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