|
|
|
Ecosystems Research Division Publications: 2008
 |
|
This page lists publication titles, citations and abstracts produced by NERL's Ecosystems Research Division for the year 2008, organized by Publication Type. Your search has returned
124 Matching Entries.
See also Ecosystems Research Division citations with abstracts:
1999,
2000,
2001,
2002,
2003,
2004,
2005,
2006,
2007,
2008
Technical Information Manager: Janice Sims - (706) 355-8011 or sims.janice@epa.gov
|
| |
|
|
|
Presented/Published |
| BOOK CHAPTER |
Analysis of the Enantiomers of Chiral Pesticides and Other Pollutants in Environmental Samples By Capillary Electrophoresis |
07/01/2008
|
|
|
|
GARRISON, A. W., P. SCHMITT-KOPPLIN, AND J. K. AVANTS. Analysis of the Enantiomers of Chiral Pesticides and Other Pollutants in Environmental Samples By Capillary Electrophoresis. Chapter 8, P. Schmitt-Kopplin (ed.), Capillary Electrophoresis Methods and Protocols. Humana Press Incorporated, Totowa, NJ, 157-170, (2008).
|
| Abstract:
|
The generic method described here involves typical capillary electrophoresis (CE) techniques, with the addition of cyclodextrin chiral selectors to the electrolyte for enantiomer separation and also, in the case of neutral analytes, the further addition of a micelle forming compound such as sodium dodecyl sulfate (SDS) for separation by the micellar electrokinetic chromatography (MEKC) mode of CE. This generic method has broad application for the separation and analysis of enantiomers of chiral pesticides and other small molecules in a variety of environmental matrices.
|
|
| BOOK CHAPTER |
Comparative Mammalian Cell Toxicity of N-DBPs and C-DBPs |
07/01/2008
|
|
|
|
Plewa, M. J., E. D. Wagner, M. G. Muellner, K. M. Hsu, AND S. D. RICHARDSON. Comparative Mammalian Cell Toxicity of N-DBPs and C-DBPs. , Chapter 3, Karanfil, T., S.W. Krasner, P. Westerhoff, and Y. Xie (ed.), Occurrence, Formation, Health Effects and Control of Disinfection By-Products in Drinking Water. American Chemical Society, Washington, DC, 36-50, (2008).
|
| Abstract:
|
In order to generate a quantitative, direct comparison amongst classes of drinking water disinfection by-products (DBPs), we developed and calibrated in vitro mammalian cell cytotoxicity and genotoxicity assays to integrate the analytical biology with the analytical chemistry of these important environmental contaminants. The generated database demonstrates the universality of the comparative toxicity of iodo- >bromo- >>chloro-DBPs across different structural DBP classes and the substantially greater toxicity of nitrogen-containing DBPs (N-DBPs) compared to carbonaceous DBPs (C-DBPs). These results are important in light of the generation of iodinated-DBPs and N-DBPs that may result from the use of alternative disinfectants.
|
|
| BOOK CHAPTER |
The Role of Ecological Endpoints in Watershed Management |
07/15/2008
|
|
|
|
RASHLEIGH, B. The Role of Ecological Endpoints in Watershed Management. , Chapter 21, I.E. Gonenc, A. Vadineanu, J.P. Wolflin, and R.C. Russo (ed.), Sustainable Use and Development of Watersheds. Springer, New York, NY, 337-348, (2008).
|
| Abstract:
|
Landscape change and pollution in watersheds affect ecological endpoints in receiving water bodies. Therefore, these endpoints are useful in watershed management. Fish and benthic macro invertebrates are often used as endpoints, since they are easily measured in the field and integrate over time and stressors. A range of approaches are used to incorporate ecological endpoints into watershed management. A common approach is the use of metrics, such as species diversity and the presence of rare or unique species; metrics are also combined into multimetric indices. Multivariate analyses are used to relate endpoints to landscape characteristics. Detailed ecological models can be used to represent effects of multiple stressors and predict the response to ecological endpoints to future conditions and alternative management scenarios. Ecological endpoints are currently used to assess or classify sites or water bodies, to identify impaired sites and waters, support water quality permits or enforcement, identify areas for conservation, or to set restoration goals or monitor progress. In the future, it is likely that ecological endpoints will be incorporated with aspects of water quality and economic valuation to create sophisticated decision support tools for watersheds.
|
|
| BOOK CHAPTER |
Watershed Management in the United States |
07/15/2008
|
|
|
|
RUSSO, R. C., B. RASHLEIGH, AND R. B. AMBROSE. Watershed Management in the United States. , Chapter 11, I.E. Gonenc, A. Vadineanu, J.P. Wolflin, and R.C. Russo (ed.), Sustainable Use and Development of Watersheds. Springer, New York, NY, 173-198, (2008).
|
| Abstract:
|
A watershed approach provides an effective framework for dealing with water resources challenges. Watersheds provide drinking water, recreation, and ecological habitat, as well as a place for waste disposal, a source of industrial cooling water, and navigable inland water transport. Consequently, much depends on the health of watersheds. Watersheds
are threatened by wastewater and nonpoint source runoff that load surface waters with excess organic matter, nutrients, pathogens, solids, and toxic substances. Physical alterations, such as paving and stream channelization, change both the hydrologic regime and habitat. Estuaries are of particular importance, since they have great economic, ecological, recreational, and aesthetic value. An approach to the protection, management, and restoration of these water resources in the United States, and the respective roles of federal, state, and local governments, as well as the private sector and volunteer groups, is discussed. Protecting and sustaining watersheds requires that water resource goals be prioritized within a coordinating framework.
|
|
| JOURNAL |
Building Model Analysis Applications With the Joint Universal Parameter Identification and Evaluation of Reliability (Jupiter) Api |
04/01/2008
|
|
|
|
BANTA, E. R., M. C. HILL, E. POETER, J. E. DOHERTY, AND J. E. BABENDREIER. Building Model Analysis Applications With the Joint Universal Parameter Identification and Evaluation of Reliability (Jupiter) Api. Computers & Geosciences. Elsevier Science Ltd, New York, NY, 34(4):310-319, (2008).
|
| Abstract:
|
The open-source, public domain JUPITER (Joint Universal Parameter IdenTification and Evaluation of Reliability) API (Application Programming Interface) provides conventions and Fortran-90 modules to develop applications (computer programs) for analyzing process models. The input and output conventions allow application users to access various applications and the analysis methods they embody with a minimum of time and effort. Process models simulate, for example, physical, chemical, and (or) biological systems of interest using phenomenological, theoretical, or heuristic approaches. The types of model analyses supported by the JUPITER API include, but are not limited to, sensitivity analysis, data needs assessment, calibration, uncertainty analysis, model discrimination, and optimization. The advantages provided by the JUPITER API for users and programmers allow for rapid programming and testing of new ideas. Application-specific coding can be in languages other than the Fortran-90 of the API. This article briefly describes the capabilities and utility of the JUPITER API, lists existing applications, and uses UCODE _ 2005 as an example.
|
|
| JOURNAL |
Development and Test Application a Screening-Level Mercury Fate Model and Tool for Evaluating Wildlife Exposure Risk for Surface Waters With Mercury-Contaminated Sediments (Serafm) |
04/01/2008
|
|
|
|
KNIGHTES, C. D. Development and Test Application a Screening-Level Mercury Fate Model and Tool for Evaluating Wildlife Exposure Risk for Surface Waters With Mercury-Contaminated Sediments (Serafm). ENVIRONMENTAL MODELLING & SOFTWARE. Elsevier Science, New York, NY, 23(4):495-510, (2008).
|
| Abstract:
|
Complex chemical cycling of mercury in aquatic ecosystems means that tracing the linkage between anthropogenic and natural loadings of mercury to watersheds and water bodies and associated concentrations in the environment are difficult to establish without the assistance of numerical models that describe biogeochemical controls on mercury distribution and availability to organisms. This paper presents an overview of a process-based, steady-state model developed for state and water quality managers and scientists to assist in ecological risk assessments for mercury in aquatic environments. SERAFM (Spreadsheet-based Ecological Risk Assessment for the Fate of Mercury) incorporates the chemical, physical, and biological processes governing mercury transport and fate in a surface water including: atmospheric deposition; watershed transport and transformation; solid transport and cycling within the water body; and water body mercury processes. This modelling framework was designed to assist risk assessors in evaluating wildlife risk at the screening level for an aquatic ecosystem with mercury contaminated sediments. An example application of the model that is used to inform a regional risk assessment is presented in this manuscript. In the example provided, hazard quotients for exposed wildlife and humans are calculated by the model for three scenarios: historical case of mercury-contaminated sediments, required clean-up levels to protect the most sensitive species, and background conditions. The spreadsheet structure of SERAFM permits dismantling and reassembling of specific sub-modules, while maintaining transparency to permit flexibility in use and application.
|
|
| JOURNAL |
Nestedness in Riverine Freshwater Mussel Communities: Patterns Across Sites and Fish Hosts |
10/01/2008
|
|
|
|
RASHLEIGH, B. Nestedness in Riverine Freshwater Mussel Communities: Patterns Across Sites and Fish Hosts. ECOGRAPHY. Blackwell Publishing, Malden, MA, 31(5):612-619, (2008).
|
| Abstract:
|
The pattern of nestedness, where species present in depauperate locations are subsets of species present in locations with higher species diversity, is often found in ecological communities. The pattern may indicate the mechanism by which the communities are structured and can be used to inform conservation efforts. Nestedness was examined in six rivers in the Tennessee River basin, using mussel data collected through the Tennessee Valley Authority's Cumberlandian Mollusk Conservation Program. The communities appeared significantly nested compared to randomly generated matrices. Species distributions were mostly unrelated to differences in immigration probabilities and only weakly related to downstream direction, giving some indication of structuring by differences in extinction. Mussel species distributions were not related to the number or distribution of their fish hosts, and mussel species were more likely to overlap on common fish hosts. Correlations indicated that mussel abundance and diversity and fish abundance and diversity were all positively correlated with one another. Nestedness may be driven by fish host abundance, where high fish host abundance promotes the survival of rare mussel species. The understanding of diversity in these streams can aid conservation of this imperiled fauna.
|
|
| JOURNAL |
Enantioselective Chronic Toxicity of Fipronil to Ceriodaphnia Dubia |
01/01/2008
|
|
|
|
WILSON, W. A., B. J. KONWICK, A. W. GARRISON, J. K. AVANTS, AND M. C. BLACK. Enantioselective Chronic Toxicity of Fipronil to Ceriodaphnia Dubia. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY. Springer, New York, NY, 54(1):36-43, (2008).
|
| Abstract:
|
Fipronil is a phenylpyrazole pesticide that has greatly increased in popularity in recent years. As a chiral molecule, fipronil is released into the environment as a 1:1 mixture (called a racemate) of its two enantiomers. Previous toxicity work has indicated that the enantiomers of fipronil exhibit significantly different levels of acute toxicity to the non-target organism Ceriodaphnia dubia. In this work, we examine the chronic effects of the pure enantiomers and racemate on the survival, development, mobility, and reproduction of C. dubia adults, and the survival and mobility of their offspring.
|
|
| JOURNAL |
Chlorpyrifos Transformation By Aqueous Chlorine in the Presence of Bromide and Natural Organic Matter |
02/27/2008
|
|
|
|
DUIRK, S. E., C. TARR, AND T. W. COLLETTE. Chlorpyrifos Transformation By Aqueous Chlorine in the Presence of Bromide and Natural Organic Matter. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY. American Chemical Society, Washington, DC, 56(4):1328-1335, (2008).
|
| Abstract:
|
The aqueous chlorination of chlorpyrifos (CP) was investigated in the presence of bromide and natural organic matter (NOM), which were identified as naturally occurring aqueous constituents that could impact CP transformation rates to the toxic product chlorpyrifos oxon (CPO). Bromide can be oxidized by chlorine to form hypobromous acid (HOBr), which was found to oxidize CP at a rate that was three orders of magnitude faster than was the case with chlorine. Similar to previous findings with the hypochlorite ion, hypobromite (OBr) was found to accelerate the hydrolysis of CP and CPO. Treated water from the Athens Clarke County (ACC) water treatment plant in Athens, Georgia, USA was used in some of the experiments as a NOM source. A mechanistic model was used to adequately predict the loss of CP as well as the formation of CPO and the hydrolysis product 3,5,6-trichloro-2-pyridinol (TCP) in the presence of the ACC water.
|
|
| JOURNAL |
Integrated Disinfection Byproducts Mixtures Research: Comprehensive Characterization of Water Concentrates Prepared from Chlorinated and Ozonated/Postchlorinated Drinking Water |
01/01/2008
|
|
|
|
RICHARDSON, S. D., A. D. THRUSTON,JR, S. W. KRASNER, H. S. WEINBERG, R. J. MILTNER, K. M. SCHENCK, M. G. NAROTSKY, A. B. MCKAGUE, AND J. E. SIMMONS. Integrated Disinfection Byproducts Mixtures Research: Comprehensive Characterization of Water Concentrates Prepared from Chlorinated and Ozonated/Postchlorinated Drinking Water. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH - PART A: CURRENT ISSUES. Taylor & Francis, Inc., Philadelphia, PA, 71(17):1165-1186, (2008).
|
| Abstract:
|
This article describes the disinfection byproduct (DBP) characterization portion of a series of experiments designed for comprehensive chemical and toxicological evaluation of two drinking water concentrates containing highly complex mixtures of DBP. This project, called the Four Lab Study, involved the participation of scientists from 4 lab and centers of the U.S. Environmental Protection Agency's (EPA) Office of Research and Development, along with collaborators from the water industry and academia, and addressed toxicologic effects of complex DBP mixtures, with an emphasis on reproductive and developmental effects that are associated with DBP exposures in epidemiologic studies. Complex mixtures of DBP from two different disinfection schemes (chlorination and ozonation/postchlorination) were concentrated successfully, while maintaining a water matrix suitable for animal studies. An array of chlorinated/brominated/iodinated DBP was created. The DBP were relatively stable over the course of the animal experiments, and a significant portion of the halogenated DBP formed in the drinking water might be accounted for through a comprehensive qualitative and quantitative identification approach. DBP quantified included priority DBP that are not regulated, but have been predicted to produce adverse health effects, as well as those currently regulated in the United States and those targeted during implementation of the Information Collection Rule. New byproducts were also reported for the first time. These included previously undetected and unreported bromo- and chloroacids, iodinated compounds, bromo- and iodophenols, and bromoalkyltins.
|
|
| JOURNAL |
Spatial and Temporal Variability of Solar Ultraviolet Exposure of Coral Assemblages in the Florida Keys: Importance of Colored Dissolved Organic Matter |
09/15/2008
|
|
|
|
ZEPP, R. G., G. C. SHANK, E. STABENAU, K. W. PATTERSON, M. J. CYTERSKI, W. S. FISHER, E. BARTELS, AND S. L. ANDERSON. Spatial and Temporal Variability of Solar Ultraviolet Exposure of Coral Assemblages in the Florida Keys: Importance of Colored Dissolved Organic Matter. LIMNOLOGY AND OCEANOGRAPHY. American Society of Limnology and Oceanography, Lawrence, KS, 53(5):1909-1922, (2008).
|
| Abstract:
|
Solar UV radiation can have deleterious effects on coral assemblages in tropical and subtropical marine environments. We present evidence that UV exposure of coral reefs in the Florida Keys is controlled primarily by chromophoric dissolved organic matter (CDOM) in waters overlying the reefs. Diffuse attenuation coefficients (Kd) were determined using downwelling vertical profiles of UV and visible radiation obtained at sites located in the Middle and Lower Keys and the Dry Tortugas. Significant linear correlations were observed between dissolved organic carbon (DOC) and Kd values in the UV spectral region (305 - 380 nm) for inshore and reef tract sites but no significant correlations between Kd and DOC were found
further offshore in bluewater sites.
|
|
| JOURNAL |
Cross-Species Comparison of Conazole Fungicide Metabolites Using Rat and Rainbow Trout (onchlorhynchus Mykiss) Hepatic Microsomes and Purified Human Cyp 3a4 |
02/01/2008
|
|
|
|
MAZUR, C. S. AND J. F. KENNEKE. Cross-Species Comparison of Conazole Fungicide Metabolites Using Rat and Rainbow Trout (onchlorhynchus Mykiss) Hepatic Microsomes and Purified Human Cyp 3a4. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 42(3):947-954, (2008).
|
| Abstract:
|
Ecological risk assessment frequently relies on cross-species extrapolation to predict acute toxicity from chemical exposures. A major concern for environmental risk characterization is the degree of uncertainty in assessing xenobiotic biotansformation processes. Although inherently complex, metabolite identification is critical to risk assessment since the product(s) formed may pose a greater toxicological threat than the parent molecule. This issue is further complicated by differences observed in metabolic transformation pathways among species. Conazoles represent an important class of azole fungicides that are widely used in both pharmaceutical and agricultural applications. The antifungal property of conazoles occurs via complexation with the cytochrome P450 monooxygenases (CYP) responsible for mediating fungal cell wall synthesis. This mode of action has cause for concern regarding the potential adverse impact of conazoles on the broad spectrum of CYP-based processes within mammalian and aquatic species. In this study, in vitro metabolic profiles were determined for thirteen conazole fungicides using rat and rainbow trout (Oncorhynchus mykiss) liver microsomes and purified human CYP 3A4. Results showed that 10 out of the 13 conazoles tested demonstrated identical metabolite profiles among rat and trout microsomes, and these transformations were well conserved via both aromatic and aliphatic hydroxylation and carbonyl reduction processes. Furthermore, nearly all metabolites detected in the rat and trout microsomal assays were detected within the human CYP 3A4 assays. These results indicate a high degree of metabolic conservation among species with an equivalent isozyme activity of human CYP 3A4 being present in both the rat and trout, and provides insight into xenobiotic biotransformations needed for accurate risk assessment.
|
|
| JOURNAL |
Analysis of Perfluorinated Carboxylic Acids in Soils II: Optimization of Chromatography and Extraction |
02/15/2008
|
|
|
|
WASHINGTON, J. W., W. M. HENDERSON, J. J. ELLINGTON, T. JENKINS, AND J. J. EVANS. Analysis of Perfluorinated Carboxylic Acids in Soils II: Optimization of Chromatography and Extraction. JOURNAL OF CHROMATOGRAPHY A. Elsevier Science Ltd, New York, NY, 1181(1-2):21-32, (2008).
|
| Abstract:
|
With the objective of detecting and quantitating low concentrations of perfluorinated carboxylic acids (PFCAs), including perfluorinated octanoic acid (PFOA), in soils, we compared the analytical suitability of liquid chromatography columns containing three different stationary phases, two different liquid chromatography tandem mass spectrometry (LC/MS/MS) systems, and eight combinations of sample-extract pretreatments, extractions and cleanups on three test soils. For the columns and systems we tested, we achieved the greatest analytical sensitivity for PFCAs using a column with a C18 stationary phase in a Waters LC/MS/MS. In this system we achieved an instrument detection limit for PFOA of 270 ag/µL, equating to about 14 fg of PFOA on-column. While an elementary acetonitrile/water extraction of soils recovers PFCAs effectively, natural soil organic matter also dissolved in the extracts commonly imparts significant noise that appears as broad, multi-nodal, asymmetric peaks that coelute with several PFCAs. The intensity and elution profile of this noise is highly variable among soils and it challenges detection of low concentrations of PFCAs by decreasing the signal-to-noise ratio. In an effort to decrease this background noise, we investigated several methods of pretreatment, extraction and cleanup, in a variety of combinations, that used alkaline and unbuffered water, acetonitrile, tetrabutylammonium hydrogen sulfate, methyl tert-butyl ether, dispersed activated carbon and solid-phase extraction. For the combined objectives of complete recovery and minimization of background noise, we have chosen: 1) alkaline pretreatment; 2) extraction with acetonitrile/water; 3) evaporation to dryness; 4) reconstitution with Tetrabutylammonium-hydrogen-sulfate ion-pairing solution; 5) ion-pair extraction to methyl-tert-butyl ether; 6) evaporation to dryness; 7) reconstitution with 60/40 acetonitrile/water (v/v) and; 8) analysis by LC/MS/MS. Using this method, we detected in all three of our test soils, endogenous concentrations of all of our PFCA analytes, C6 through C10 -- the lowest concentrations being roughly 30 pg/g of dry soil for perfluorinated hexanoic and decanoic acids in an agricultural soil.
|
|
| JOURNAL |
Calibration of Subsurface Batch and Reactive-Transport Models Involving Complex Biogeochemical Processes |
02/01/2008
|
|
|
|
MATOTT, L. S. AND A. J. RABIDEAU. Calibration of Subsurface Batch and Reactive-Transport Models Involving Complex Biogeochemical Processes. ADVANCES IN WATER RESOURCES. Elsevier Science Ltd, New York, NY, 31(2):269-286, (2008).
|
| Abstract:
|
In this study, the calibration of subsurface batch and reactive-transport models involving complex biogeochemical processes was systematically evaluated. Two hypothetical nitrate biodegradation scenarios were developed and simulated in numerical experiments to evaluate the performance of three calibration search procedures: a multi-start non-linear regression algorithm (i.e. multi-start Levenberg-Marquardt), a global search heuristic (i.e. particle swarm optimization), and a hybrid algorithm that combines the particle swarm procedure with a regression-based polishing step. Graphical analysis of the selected calibration problems revealed heterogeneous regions of extreme parameter sensitivity and insensitivity along with abundant numbers of local minima. These characteristics hindered the performance of the multi-start non-linear regression technique, which was generally the least effective of the considered algorithms. In most cases, the global search and hybrid methods were capable of producing improved model fits at comparable computational expense. In other cases, the multi-start and hybrid calibration algorithms yielded comparable fitness values but markedly differing parameter estimates and associated uncertainty measures.
|
|
| JOURNAL |
Isofit a Program for Fitting Sorption Isotherms to Experimental Data |
05/01/2008
|
|
|
|
MATOTT, L. S. AND A. J. RABIDEAU. Isofit a Program for Fitting Sorption Isotherms to Experimental Data. ENVIRONMENTAL MODELLING & SOFTWARE. Elsevier Science, New York, NY, 23(5):670-676, (2008).
|
| Abstract:
|
Isotherm expressions are important for describing the partitioning of contaminants in environmental systems. ISOFIT (ISOtherm FItting Tool) is a software program that fits isotherm parameters to experimental data via the minimization of a weighted sum of squared error (WSSE) objective function. ISOFIT supports a number of isotherms, including several dual-mode isotherms that combine Freundlich, Langmuir, and Polanyi expressions with a linear partitioning term. To minimize the WSSE objective function, ISOFIT utilizes a hybrid optimization procedure that combines particle swarm optimization with Levenberg-Marquardt nonlinear regression. An initial swarm optimization step identifies promising solutions while circumventing local minima and the follow-on regression step provides local refinement and facilitates the calculation of numerous regression statistics. To demonstrate ISOFIT and evaluate its performance, the program was applied to a readily available sorption dataset and benchmarked against results generated using the MS Excel solver package.
|
|
| JOURNAL |
An Assessment of the Fate of Metal Oxide Nanomaterials in Porous Media |
09/11/2008
|
|
|
|
LOUX, N. T. AND N. SAVAGE. An Assessment of the Fate of Metal Oxide Nanomaterials in Porous Media. WATER, AIR, AND SOIL POLLUTION. Springer, New York, NY, 194(1-4):227-241, (2008).
|
| Abstract:
|
Developing procedures for assessing the potential environmental fate and transport of nanomaterials is an active endeavor of the environmental technical research community. Insufficient information exists for estimating the likelihood of nanomaterial deposition on natural surfaces in aquatic environments. This work develops a framework for estimating potential metal oxide nanomaterial self-aggregation through the combined application of recent developments in diffuse layer model surface complexation theory with historical DLVO procedures. Findings from the work include: 1) the surface and/or zeta potential of nanomaterials in environmental aqueous systems is likely to have an absolute value less than 25 mV, 2) only nanomaterials with a Hamaker constant as large as 1E-19 J (and an absolute surface potential ≤25 mV) will likely aggregate in most environmental aquatic media, 3) natural organic matter coatings may render metal oxide nanomaterials less likely to aggregate in aquatic media, 4) nanomaterials in aqueous suspension will likely have an absolute surface potential less than their micron-sized counterparts of the same composition, and 5) robust diffuse layer model databases of intrinsic surface site reactivity constants with multivalent aqueous environmental ions will need to be developed in order to provide accurate mechanistic estimates of the surface potential of nanoparticles suspended in aqueous environmental systems.
|
|
| JOURNAL |
Occurrence, Synthesis and Mammalian Cell Cytotoxicity and Genotoxicity of Haloacetamides: An Emerging Class of Nitrogenous Drinking Water Disinfection By-Products |
02/01/2008
|
|
|
|
Plewa, M. J., M. G. Muellner, S. D. RICHARDSON, F. Fasano, K. M. Buettner, Y. WOO, A. B. McKague, AND E. D. Wagner. Occurrence, Synthesis and Mammalian Cell Cytotoxicity and Genotoxicity of Haloacetamides: An Emerging Class of Nitrogenous Drinking Water Disinfection By-Products. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 42(3):955-961, (2008).
|
| Abstract:
|
The haloacetamides, a class of emerging nitrogenous drinking water disinfection by-products (DBPs), were analyzed for their chronic cytotoxicity and for the induction of genomic DNA damage in Chinese hamster ovary cells.
|
|
| JOURNAL |
Investigating Compensation and Recovery of Fathead Minnow (pimephales Promelas) Exposed to 17α-Ethynylestradiol With Metabolite Profiling |
06/01/2008
|
|
|
|
EKMAN, D. R., Q. TENG, D. L. VILLENEUVE, M. D. KAHL, K. M. JENSEN, E. J. DURHAN, G. T. ANKLEY, AND T. W. COLLETTE. Investigating Compensation and Recovery of Fathead Minnow (pimephales Promelas) Exposed to 17α-Ethynylestradiol With Metabolite Profiling. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 42(11):4188-4194, (2008).
|
| Abstract:
|
1H-NMR spectroscopy was used to profile metabolite changes in the livers of fathead minnows (Pimephales promelas) exposed to the synthetic estrogen 17α ethynylestradiol (EE2) via a continuous flow water exposure. Fish were exposed to either 10 or 100 ng EE2/L for 8 days, followed by an 8 day depuration phase. Livers were collected after days 1, 4 and 8 of the exposure, and at the end of the depuration phase. Analysis of polar extracts of the liver revealed a greater impact of EE2 on males than females, with metabolite profiles of the former assuming similarities with those of the females (i.e., feminization) early in the exposure. Biochemical effects observed in the males included changes in metabolites relating to energetics (e.g., glycogen, glucose, and lactate) and liver toxicity (creatine, bile acids). In addition, amino acids associated with vitellogenin (VTG) synthesis increased in livers of EE2-exposed males, a finding consistent with increased plasma concentrations of the lipoprotein in the fish. Using partial least squares discriminant analysis (PLS-DA), the response trajectories of the males at both exposure concentrations were compared. This revealed an apparent ability of the fish to compensate for the presence of EE2 later in the exposure, and to partially recover from its effects after the chemical was removed.
|
|
| JOURNAL |
Effect of Natural Organic Matter on the Reduction of Nitroaromatics By Fe(ii) Species |
09/01/2008
|
|
|
|
COLON, D., E. J. WEBER, AND J. L. Anderson. Effect of Natural Organic Matter on the Reduction of Nitroaromatics By Fe(ii) Species. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 42(17):6538-6543, (2008).
|
| Abstract:
|
Although natural organic matter is a necessary electron source for the microbial mediated development of redox zones in nature, uncertainty still exists regarding its role(s) in the reduction of chemicals. This work studied the effect of Suwannee river humic acid (SRHA) on the reduction of p-monosubstituted nitrobenzenes in Fe(II)-treated goethite suspensions.
|
|
| JOURNAL |
Brazilian Free-Tailed Bats (Tadarida Brasiliensis) as Insect Pest Regulators in Transgenic and Conventional Cotton Crops |
06/01/2008
|
|
|
|
Federico, P., T. G. Hallam, G. F. McCracken, S. T. PURUCKER, W. E. Grant, A. N. Correa Sandoval, J. K. Westbrook, R. A. Medellin, C. J. Cleveland, C. G. Sansone, J. D. Lopez, M. Betke, A. Moreno-Valdez, AND T. H. Kunz. Brazilian Free-Tailed Bats (Tadarida Brasiliensis) as Insect Pest Regulators in Transgenic and Conventional Cotton Crops. ECOLOGICAL APPLICATIONS. Ecological Society of America, Ithaca, NY, 18(4):826-837, (2008).
|
| Abstract:
|
During the past 12,000 years agricultural systems have transitioned from natural habitats to conventional agricultural regions, and recently to large areas of genetically- engineered (GE) croplands. This GE revolution occurred for cotton in a span of slightly more than a decade where a switch occurred in major cotton production areas from growing 100% conventional cotton to an environment where 95% transgenics are grown. Ecological interactions between GE targeted insects and non-targeted insectivorous insects have been investigated. However, the relationships between ecological functions (such as herbivory and ecosystem transport) and agronomic benefits of avian or mammalian insectivores in the transgenic environment are generally remain unclear. However, the importance of some agricultural pest management services provided by insectivorous species such as the Brazilian free-tailed bat, Tadarida brasiliensis, have been recognized.
|
|
| JOURNAL |
Scale Dependence in the Species-Discharge Relationship for Fishes of the Southeastern U.S.A. |
10/01/2008
|
|
|
|
MCGARVEY, D. J. AND G. M. Ward. Scale Dependence in the Species-Discharge Relationship for Fishes of the Southeastern U.S.A. FRESHWATER BIOLOGY. Blackwell Publishing, Malden, MA, 53(11):2206-2219, (2008).
|
| Abstract:
|
Species-discharge relationships (SDR) are aquatic analogues of species-area relationships, and are increasingly used in both basic research and conservation planning. SDR studies are often limited, however, by two shortcomings. First, they do not determine whether the reported SDR’s, which normally use complete drainage basins as sampling units, are scale-dependent. Second, they do not account for the effects of habitat diversity within or among samples. We addressed both problems by using discrete fish zones as sampling units in a SDR analysis. To do so, we first tested for longitudinal zonation in three southeastern (U.S.A.) rivers. In each river, we detected successive ‘lower’, ‘middle’, and ‘upper’ fish zones, which were characterized by distinct fish assemblages with predictable habitat requirements. Because our analyses combined fish data from multiple sources, we also used rarefaction and Monte Carlo simulation to ensure that our zonation results were robust to spurious sampling effects. Next, we estimated the average discharge within each zone, and plotted these estimates against their respective richnesses (log10 data). Notably, this zonal SDR fit the empirical data better than a comparable SDR that did not discriminate among longitudinal zones. We therefore conclude that the southeastern fish SDR is scale-dependent, and that accounting for within-basin habitat diversity is an important step in explaining the high diversity of southeastern fishes. Lastly, we discuss how our zonal SDR can be used to improve conservation planning. Specifically, we show how the slope of the SDR can be used to forecast potential extinction rates, and how the zonal data can be used to identify species of greatest concern.
|
|
| JOURNAL |
Dietary Uptake Models Used for Modeling the Bioaccumulation of Organic Contaminants in Fish |
04/01/2008
|
|
|
|
BARBER, M. C. Dietary Uptake Models Used for Modeling the Bioaccumulation of Organic Contaminants in Fish. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 27(4):755-777, (2008).
|
| Abstract:
|
Numerous models have been developed to predict the bioaccumulation of organic chemicals in fish. Although chemical dietary uptake can be modeled using assimilation efficiencies, bioaccumulation models fall into two distinct groups. The first group implicitly assumes that assimilation efficiencies describe the net chemical exchanges between fish and their food. These models describe chemical elimination as a lumped process that is independent of the fish's egestion rate or as a process that does not require an explicit fecal excretion term. The second group, however, explicitly assumes that assimilation efficiencies describe only actual chemical uptake and formulates chemical fecal and gill excretion as distinct, thermodynamically driven processes. After reviewing the derivations and assumptions of the algorithms that have been used to describe chemical dietary uptake of fish, their application, as implemented in 16 published bioaccumulation models, is analyzed for largemouth bass (Micropterus salmoides), walleye (Sander vitreus = Stizostedion vitreum), and rainbow trout (Oncorhynchus mykiss) that bioaccumulate an unspecified, poorly metabolized, hydrophobic chemical possessing a log KOW of 6.5 (i.e., a chemical similar to a pentachlorobiphenyl).
|
|
| JOURNAL |
Simple Approaches for Measuring Dry Atmospheric Nitrogen Deposition to Watersheds |
09/23/2008
|
|
|
|
GOLDEN, H. E., E. W. Boyer, M. G. Brown, AND D. K. Lee. Simple Approaches for Measuring Dry Atmospheric Nitrogen Deposition to Watersheds. WATER RESOURCES RESEARCH. American Geophysical Union, Washington, DC, 44:W00D02, (2008).
|
| Abstract:
|
Assessing the effects of atmospheric nitrogen (N) deposition on surface water quality requires accurate accounts of total N deposition (wet, dry, and cloud vapor); however, dry deposition is difficult to measure and is often spatially variable. Affordable passive sampling methods are available for estimating "hotspots" and spatial variations of gaseous dry N deposition (i.e., nitrogen dioxide (NO2) and ammonia (NH3)), though few viable methods for estimating the deposition from nitric acid (HNO3) gas using passive sampling techniques exist. We consider passive sampling approaches for assessing spatial patterns of dry atmospheric N deposition across watersheds and a potential method for monitoring spatial variations in the magnitude of HNO3 in the atmosphere using simple passive monitoring techniques. We demonstrate the applicability of passive samplers for use in water quality modeling, watershed nitrogen budgets, and watershed management through a review of previous applications and via our own case study in the South Korean peninsula.
|
|
| JOURNAL |
Extending the Diffuse Layer Model of Surface Acidity Constant Behavior: II. Estimation of Intrinsic Acidity and Electrolyte Ion Site Binding Constants |
08/01/2008
|
|
|
|
LOUX, N. T. Extending the Diffuse Layer Model of Surface Acidity Constant Behavior: II. Estimation of Intrinsic Acidity and Electrolyte Ion Site Binding Constants. CHEMICAL SPECIATION AND BIOAVAILABILITY. Science and Technology Letters, 20(3):161-172, (2008).
|
| Abstract:
|
The two-pK metal oxide surface acidity constant model relies on generic mass action expressions of the form: Ka = [>SOHx-1x-2]aH+EXP(-ΔGexcess/RT)/[>SOHxX-l] where x equals 1 or 2. While all current two-pK surface complexation models require numerical estimates of "intrinsic" acidity constants (i.e., Ka values when ΔGexcess equals zero), there exists a large range in the metal oxide intrinsic acidity constant values reported in the literature. This paper describes improved procedures for obtaining intrinsic acidity constants from published metal oxide titrimetic datasets. Because of the observed ionic strength sensitivity of acidity constant estimates at zero charge conditions, these constants were interpreted within the context of a new procedure for estimating historical electrolyte ion site binding constants.
|
|
| JOURNAL |
Prediction of Daily Flow Duration Curves and Streamflow for Ungauged Catchments Using Regional Flow Duration Curves |
06/01/2008
|
|
|
|
MOHAMOUD, Y. M. Prediction of Daily Flow Duration Curves and Streamflow for Ungauged Catchments Using Regional Flow Duration Curves. Hydrological Sciences Journal. IAHS LIMITED, Oxford, Uk, 53(4):706-724, (2008).
|
| Abstract:
|
This study presents a method to predict flow duration curves (FDCs) and streamflow for ungauged catchments in the Mid-Atlantic Region, USA. We selected 29 catchments from the Appalachian Plateau, Ridge and Valley, and Piedmont physiographic provinces to develop and test the proposed method. Using a stepwise multiple regression analysis, the dominant climate-landscape descriptors were identified and regional FDC models were developed for each province. Predictive performance of the proposed method was estimated using data from three evaluation sites that were not included in parameter estimation for the regional FDC models. Results of this study show that climate and geomorphological descriptors strongly influence the hydrology of the Appalachian Plateau and some Ridge and Valley catchments, whereas soil and geomorphological descriptors strongly influence the hydrology of the Piedmont and some Ridge and Valley catchments. Streamflows calculated by the drainage area ratio method and streamflows reconstructed by the FDC method were compared with the observed streamflows. The results indicated that the FDC-based method shows great promise for predicting streamflow in ungauged basins.
|
|
| JOURNAL |
Environmental Mass Spectrometry: Emerging Contaminants and Current Issues, 2008 Review |
06/15/2008
|
|
|
|
RICHARDSON, S. D. Environmental Mass Spectrometry: Emerging Contaminants and Current Issues, 2008 Review. ANALYTICAL CHEMISTRY. American Chemical Society, Washington, DC, 80(12):4373-4402, (2008).
|
| Abstract:
|
This biennial review covers developments in Environmental Mass Spectrometry for Emerging Environmental Contaminants over the period of 2006-2007. A few significant references that appeared between January and February 2008 are also included. Analytical Chemistry’s current policy is to limit reviews to a maximum of 250 significant references and to mainly focus on new trends. As a result, as was done in the previous 2006 Environmental Mass Spectrometry review, this 2006 review will be limited to new, emerging contaminants and environmental issues that are driving most of the current research. Even with a more narrow focus, only a small fraction of the quality research publications could be discussed. Thus, this review will not be comprehensive, but will highlight new areas and discuss representative papers in the areas of focus.
|
|
| JOURNAL |
Impact of Urbanization on Water Quantity and Quality: the Need for An Integrative Watershed Modeling Approach |
07/15/2008
|
|
|
|
MOHAMOUD, Y. M. Impact of Urbanization on Water Quantity and Quality: the Need for An Integrative Watershed Modeling Approach. WATER RESOURCES IMPACT. American Water Resources Association, Middleburg, VA, 10(4):27-29, (2008).
|
| Abstract:
|
Economic development through natural resource extraction is the primary driver of land use change. Land use change generally occurs as a result of urban development (residential, commercial, and industrial), agriculture (pasture and crop production), forestry (wood for construction and paper), transportation (roads and railways), mining, and water resources development (multi-purpose dams and reservoirs). Resource extraction is crucial to economic growth but without sustainable natural resources management strategies in place these economic gains may cause serious environmental consequences. Our focus here is on urbanization and its effects on water quantity and quality. The impacts of urbanization are multi-faceted and not limited to water quantity and water quality alterations, but also the consequences of these alterations on the health of aquatic ecosystems and reliability of municipal water supply systems.
|
|
| JOURNAL |
Nowcasting and Forecasting Concentrations of Biological Contaminants at Beaches: A Feasibility and Case Study |
07/01/2008
|
|
|
|
FRICK, W. E., Z. GE, AND R. G. ZEPP. Nowcasting and Forecasting Concentrations of Biological Contaminants at Beaches: A Feasibility and Case Study. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 42(13):4818-4824, (2008).
|
| Abstract:
|
Public concern over microbial contamination of recreational waters has increased in recent years. A common approach to evaluating beach water quality has been to use the persistence model which assumes that day-old monitoring results provide accurate estimates of current concentrations. This model is frequently incorrect. Recent studies have shown that, frequently, statistical regression models based on least squares fitting are more accurate. To make such models more generally available, the Virtual Beach (VB) tool was developed. VB is public-domain software that prescribes site-specific predictive models. In this study we used VB as a tool to evaluate statistical modeling for predicting E coli levels at Huntington Beach, on Lake Erie. The models were based on readily available weather and environmental data, plus U.S. Geological Service onsite data. Although models for Great Lakes beaches have frequently been fitted to multi-year data sets, this work demonstrates that useful statistical models can be based on limited data sets collected over much shorter time periods, leading to dynamic models that are periodically refitted as new data become available. Comparisons of the resulting nowcasts (predictions of current, but yet unknown, bacterial levels) with observations verified the effectiveness of VB and showed that dynamic models are about as accurate as long-term static models. Finally, fitting models to forecasted explanatory variables, bacteria forecasts were found to compare favorably to nowcasts.
|
|
| JOURNAL |
Simulating the Vapour Phase Air/Water Exchange of P,p′-Dde, P,p′-Ddt, Lindane, and 2,3,7,8-Tetrachlorodibenzodioxin |
06/01/2008
|
|
|
|
LOUX, N. T. Simulating the Vapour Phase Air/Water Exchange of P,p′-Dde, P,p′-Ddt, Lindane, and 2,3,7,8-Tetrachlorodibenzodioxin. CHEMICAL SPECIATION AND BIOAVAILABILITY. Science and Technology Letters, 20(2):77-91, (2008).
|
| Abstract:
|
Uncertainties in our understanding of gaseous air/water exchange have emerged as major sources of concern in efforts to construct global and regional mass balances of both the green house gas carbon dioxide and semi-volatile persistent, bioaccumulative and toxic chemicals. Hoff et al. (1996) suggested that these uncertainties result from a lack of understanding of the overall gaseous air/water mass transport process as well as imprecision in our ability to perform the necessary physicochemical property measurements of the gaseous species of interest. In this work, nine low to intermediate wind speed-dependent mass transport models were evaluated as to their suitability for simulating air/water gaseous exchange of 2,3,7,8-TCDD, p,p′-DDT, p,p′-DDE and lindane. In addition, two physicochemical property estimation procedures were examined over an environmental temperature range of 0 to 40°C and compared with observations reported elsewhere in the literature. Findings from the work included: (1) the gaseous air/water exchange paradigm published by Mackay and Yeun (1983) appears to be the most robust, (2) models derived from environmental SF6 exchange data may generate upper limits for overall mass transfer coefficients but also may overestimate gaseous air/water exchange for compounds with small Henry's Law constants, and (3) neither the property estimation procedures outlined by Paasiverta et al. (1999) nor those by Hilal et al. (2003) are suitable for all physicochemical property estimates; instead, combinations of property estimation procedures from both may be most useful.
|
|
| PAPER IN NON-EPA PROCEEDINGS |
Modeled Watershed Runoff Associated With Variations in Precipitation Data, With Implications for Contaminant Fluxes: Initial Results |
09/08/2008
|
|
|
|
GOLDEN, H. E., C. D. KNIGHTES, E. COOTER, AND R. L. DENNIS. Modeled Watershed Runoff Associated With Variations in Precipitation Data, With Implications for Contaminant Fluxes: Initial Results. In Proceedings, Third Interagency Conference on Research in the Watersheds, Estes Park, CA, September 08 - 11, 2008. United States Geological Survey, Denver, CO, 1-6, (2008).
|
| Abstract:
|
Precipitation is one of the primary forcing functions of hydrologic and watershed fate and transport models; however, in light of advances in precipitation estimates across watersheds, data remain highly uncertain. A wide variety of simulated and observed precipitation data are available for use in regional air quality models and watershed fate and transport models. Although these single media models can potentially link together to estimate contaminant loadings issuing from watersheds, questions remain concerning how precipitation data from diverse sources used within each model affect water and contaminant mass balances. We assess how two sets of spatially distributed precipitation data, simulated at 12km grid and 36km grid resolutions, affect runoff simulated from a spatially distributed grid-based mercury watershed model that has been calibrated using observed precipitation data. We focus on two headwater catchments in the Cape Fear River Basin, North Carolina. Our initial results suggest that precipitation data simulated at a coarse resolution (e.g., 36km grid) decreases the efficiency and goodness-of-fit of modeled runoff, but this is watershed specific. Variations in the response to coarse resolution precipitation potentially results from differences in the size and within stream structural modifications of each watershed. These initial results are assessed within the context a broader project that will also evaluate the effects of radar and empirically-estimated precipitation data sets on modeled runoff and variations in watershed contaminant loading resulting from these diverse precipitation inputs.
|
|
| PRESENTATION |
Dispersant Effectiveness on Oil Spills Empirical Correlations |
05/04/2008
|
|
|
|
NAGARAJAN, K., N. DESHPANDE, G. A. SORIAL, AND J. W. WEAVER. Dispersant Effectiveness on Oil Spills Empirical Correlations. Presented at 2008 International Oil Spill Conference, Savannah, GA, May 04 - 08, 2008.
|
| Abstract:
|
When a dispersant is applied to an oil slick, its effectiveness in dispersing the spilled oil depends on various factors such as oil properties, wave mixing energy, temperature of both oil and water, and salinity of the water. Estuaries represent water with varying salinities. In this study three salinity values in the range of 10-34 ppt were investigated, representing potential salinity concentrations found in typical estuaries. Three oils were chosen to represent light refined oil, light crude oil and medium crude oil. Each oil was tested at three weathering levels to represent maximum, medium and zero weathering. Two dispersants were chosen for evaluation. A modified trypsinizing flask termed the "Baffled Flask" was used for conducting the experimental runs. A full factorial experiment was conducted for each oil to investigate the effect of salinity (3 levels), temperature (6 levels), oil weathering (3 levels) and mixing energy(150, 200, and 250 rpm) on dispersant effectiveness. Each experiment was replicated four times in order to evaluate the accuracy of the test. Statistical analyses of the experimental data were performed separately for each of the three oils three times (with or without dispersant). Viscosity of the three oils at the different temperatures and weathering conditions were determined. An empirical correlation of the viscosity for each of the three oils was then obtained. A linear regression model incorporating the viscosity correlations to represent temperature and weathering, the other remaining main factors (salinity and flask speed) and second order interactions among the factors was developed and was found to accurately represent the experimental data. The empirical approach to the interaction between the dispersant and oil slick developed could provide a useful or practical approach for including dispersants in a model to assess the impacts of dispersant usage on oil spills.
|
|
| PRESENTATION |
Impacts of Dissolved Organic Matter Variability on Corals-Associated Microbial Communities in the Florida Keys |
03/03/2008
|
|
|
|
SHANK, G. C., R. G. ZEPP, E. BARTELS, AND K. RITCHIE. Impacts of Dissolved Organic Matter Variability on Corals-Associated Microbial Communities in the Florida Keys. Presented at 2008 Ocean Sciences Meeting, Orlando, FL, March 02 - 07, 2008.
|
| Abstract:
|
Coral reefs in the Florida Keys have experienced a significant decrease in coral cover over the past few decades with most reefs currently exhibiting <10% overall coral cover. Environmental factors that are routinely examined for their impact on coral vitality include nutrients, turbidity, water temperature, and light availability. Our research is exploring whether fluctuations in the magnitude and/or chemical structure of the dissolved organic matter pool (DOM) influence the health of this imperiled coral ecosystem. We are evaluating DOM variability near reefs throughout the middle and lower Keys and investigating the direct relationship between microbial communities within the coral surface mucopolysaccharide layer and ambient water column DOM conditions. In the middle and lower Keys, DOC concentrations can range from <100 to 300 µM C at patch reefs near shore and from <100 to 200 µM C along the fringing reef tract. Variability in the magnitude of the DOM pool is strongly correlated with daily and seasonal pulses of Florida Bay discharge, but local sources of dissolved organic matter likely become important during periods of decreased flow from Florida Bay. Additional data indicates that the bioavailability of DOM emanating from Florida Bay is enhanced by photochemical breakdown of its higher MW pool. We are investigating whether bacterial communities associated with corals are stimulated by DOM that is bioavailable to water column microbes.
|
|
| PRESENTATION |
Photobiogeochemistry of Sargassum: A Potentially Important Source of Chromophoric Dissolved Organic Matter in the Upper Ocean |
03/03/2008
|
|
|
|
ZEPP, R. G., G. C. SHANK, A. VAHATALO, E. BARTELS, AND R. JONES. Photobiogeochemistry of Sargassum: A Potentially Important Source of Chromophoric Dissolved Organic Matter in the Upper Ocean. Presented at 2008 Ocean Sciences Meeting, Orlando, FL, March 02 - 07, 2008.
|
| Abstract:
|
Sargassum is a genus of widely distributed, generally planktonic macroalgae that often is found near the surface of the ocean. Here we report that a consortium of commonly occurring species in the Gulf of Mexico, Caribbean Sea and North Atlantic, Sargassum natans and Sargassum fluitans, are a source of chromophoric dissolved organic matter (CDOM) that contributes to the optical properties and photobiogeochemistry of the upper ocean. The production and light induced degradation of CDOM from sargassum was examined under field conditions and controlled conditions in the laboratory. The laboratory studies measured the temperature and light-dependence of CDOM production from sargassum and photodegradation of the spectral (UV-visible, fluorescence) properties of CDOM produced. These studies indicate that CDOM (based on absorption coefficients at 350 nm) is released from sargassum (0.003-0.009 m-1g-1h-1) at significant rates and that CDOM production increases sharply with increasing temperature and with exposure of the sargassum colonies to natural sunlight. The CDOM produced by sargassum is photodegraded under simulated sunlight with half-lives of 25-30 hours, and the spectral slope coefficients of its UV-visible absorption spectra (about 16 µm-1) are in the range of S-values generally observed in ocean water. Sargassum derived CDOM thus likely contributes significantly to remotely sensed observations of ocean color and to attenuation of solar UV radiation in the upper ocean.
|
|
| PRESENTATION |
Light-Induced Processes Affecting Enterococci in Aquatic Environments |
03/03/2008
|
|
|
|
JONES, R., R. G. ZEPP, M. J. CYTERSKI, M. MOLINA, AND E. M. WHITE. Light-Induced Processes Affecting Enterococci in Aquatic Environments. Presented at 2008 Ocean Sciences Meeting, Orlando, FL, March 02 - 07, 2008.
|
| Abstract:
|
Fecal indicator bacteria such as enterococci have been used to assess contamination of freshwater and marine environments by pathogenic microorganisms. Various past studies have shown that sunlight plays an important role in reducing concentrations of culturable enterococci and other indicator microorganisms in aquatic environments. Results presented here indicate that several pathways contribute to the light-induced mortality of enterococci in natural waters. Studies of one species of enterococci, Enterococci faecalis, showed that a key mechanism involves mortality via direct absorption of the UV component of sunlight. Chromophoric dissolved organic matter (CDOM) and suspended sediments also can play a role in indirect pathways for light-induced deactivation. CDOM photosensitizes the production of reactive oxygen species that can affect the survivability of enterococci. Enterococci are predominantly sorbed to sediments in aquatic environments and our results showed that the sorbed enterococci from sediments of local streams were rapidly inactivated by sunlight exposure. These results suggest that photoinduced damage can be initiated by substances on the sediment surface.
|
|
| PRESENTATION |
Using Pharmacokinetic Data to Interpret Metabolomic Changes in Cd-1 Mice Treated With Triazole Fungicides |
03/17/2008
|
|
|
|
HENDERSON, W. M., J. F. KENNEKE, T. W. COLLETTE, AND S. E. RITGER. Using Pharmacokinetic Data to Interpret Metabolomic Changes in Cd-1 Mice Treated With Triazole Fungicides. Presented at Society of Toxicology Annual Meeting, Seattle, WA, March 16 - 20, 2008.
|
| Abstract:
|
Triazoles are a class of fungicides widely used in both pharmaceutical and agricultural applications. These compounds elicit a variety of toxic effects including disruption of normal metabolic processes such as steroidogenesis. Metabolomics is used to measure dynamic changes in endogenous metabolite levels to help understand the biochemical impacts of exposure to xenobiotics. Understanding exposure pharmacokinetics (i.e., metabolism and distribution), coupled with changes in the endogenous metabolome, will help link parent and metabolically derived chemical interactions with the normal biological processes occurring in vivo. In the first study, male CD-1 mice were orally dosed with triadimefon (TDN; 50 or 115 mg/kg/d), propiconazole (PRO; 75 or 150 mg/kg/d) or myclobutanil (MYC; 75 or 150 mg/kg/d) in 10% glycerol formal for 4 days. Daily urine samples were obtained and tissues collected on days 1, 3, and 5. A second study was conducted to investigate the pharmacokinetic parameters of each triazole, and in this study mice received a single oral bolus dose of each fungicide (TDN, PRO, or MYC) and tissues were excised at 0.25, 0.5, 1, 2, 3, 6, 12 and 24 hrs post-treatment. Serum, liver, gonad and fat were extracted and then analyzed via GC/MS to determine chemical concentration. Absorption and metabolism of the triazole fungicides occurred rapidly in vivo. In general, both the parent compound and its transformation products were no longer detectable by 24 hrs post-treatment. Metabolomic analyses of urine, serum and liver were similarly conducted via GC/MS following a two-step derivatization process. Because these compounds are known to disrupt steroidogenesis, the above method was also used to target steroid levels in serum and liver samples. Ultimately, this research will aid in linking both xenobiotic- and metabolomic- biomarkers following triazole fungicide exposure.
|
|
| PRESENTATION |
Xenobiotic Metabolism Research and Its Application to Human and Ecological Exposure and Risk Assessment |
03/17/2008
|
|
|
|
KENNEKE, J. F., C. S. MAZUR, W. M. HENDERSON, A. W. GARRISON, S. E. RITGER, T. SACK, C. BROWN, AND J. K. AVANTS. Xenobiotic Metabolism Research and Its Application to Human and Ecological Exposure and Risk Assessment. Presented at Society of Toxicology Annual Meeting, Seattle, WA, March 16 - 20, 2008.
|
| Abstract:
|
A major uncertainty in risk assessment is determining the exposure of a target organism to a chemical stressor, and a confounding factor is the transformation of the chemical to a toxic metabolite inside the target organism. Physiologically-based pharmacokinetic (PBPK) models are the preferred tool to describe the fate of xenobiotics in physiological systems, since these models can be used to evaluate target tissue dose relative to route of uptake. One major obstacle to fully implementing PBPK models for risk assessment is the lack of xenobiotic metabolism data for a majority of organic chemicals in use. This data gap becomes an even greater obstacle when risk is extrapolated across species such as from rat to human or to an ecologically important organism. In an effort to close this data gap, we develop and apply innovative techniques for elucidating the kinetics and mechanisms of xenobiotic metabolism, and apply these techniques to the understanding and modeling of chemical exposure for informing human health and ecological risk assessment. Unique to our program, concomitant substrate depletion and metabolite formation kinetic parameters (i.e., Vmax and KM) are determined using non-linear models. Specific enzyme inhibitors, purified recombinant human cytochrome P450s (CYPs), stable isotopes, stereoselectivity and molecular docking are used to elucidate the mechanisms of xenobiotic metabolism. Kinetic parameters and mechanistic information are integrated to develop PBPK models, which are then validated in vivo. The entire paradigm, from metabolite map elucidation to PBPK model development, is applied across multiple species (e.g., human, rodent, fish, crustacean and insect) to develop and test cross-species extrapolations for human health and ecological risk assessment. We will illustrate this paradigm and its application to risk assessment using results from 20 conazole fungicides and the piscicide antimycin A.
|
|
| PRESENTATION |
The Importance of Concurrent Monitoring and Modeling for Understanding Mercury Exposure in the Environment |
05/20/2008
|
|
|
|
KNIGHTES, C. D. The Importance of Concurrent Monitoring and Modeling for Understanding Mercury Exposure in the Environment. Presented at National Water Quality Monitoring Conference, Atlantic City, NJ, May 18 - 22, 2008.
|
| Abstract:
|
Understanding the cycling processes governing mercury exposure in the environment requires sufficient process-based modeling and monitoring data. Monitoring provides ambient concentration data for specific sample times and locations. Modeling provides a tool for investigating the processes governing mercury exposure, providing insight into predictions of pasts and futures, and wildlife and human exposure risks. Both monitoring and modeling provide valuable information on their own, and one can be tempted to focus solely on one or the other. However, neither of these can be effectively used in isolation to address the mercury problem. By designing sampling strategies for monitoring concurrently with developing a site-specific modeling structure, a more complete picture of mercury exposure can be drawn connecting data temporally and spatially and anchoring modeling results. The difficulty lies when monitoring is done first and then modeling is attempted after the fact. In this presentation the case is made for combining modeling with monitoring at the onset of an ecosystem investigation by demonstrating benefits associated with more tightly coupled monitoring and modeling programs.
|
|
| PRESENTATION |
Watershed Nitrogen Modeling: Benefits of Diverse Approaches Using a Case Study from New York State |
05/19/2008
|
|
|
|
GOLDEN, H. E., C. D. KNIGHTES, AND E. W. BOYER. Watershed Nitrogen Modeling: Benefits of Diverse Approaches Using a Case Study from New York State. Presented at National Water Quality Monitoring Conference, Atlantic City, NJ, May 18 - 22, 2008.
|
| Abstract:
|
Watershed-scale models have evolved as an important tool for estimating the sources, transformation, and transport of contaminants to surface water systems. A wide variety of modeling approaches exist for estimating inputs, fate, and transport of constituents but most are broadly mathematically categorized as either statistical or process-based. Selection of either approach is often determined by the level of computational detail required for the intended output, spatiotemporal scales of the project or research, and the skills and desired outcomes of the end-user audience. Our work aims to evaluate the efficacy of statistical versus process-based modeling for assessing exposures in surface water systems. Here we focus on a specific driver of watershed nutrient models, presenting a statistical model for estimating contemporary atmospheric inputs of nitrogen to multiple-scale watersheds across New York State and comparing this approach to process-based atmospheric deposition models (e.g., CMAQ). Movement toward hybrid approaches for fate and transport modeling (e.g., SPARROW) in some modeling communities suggests that these two ostensibly disparate approaches can be complementary and that neither modeling approach needs to operate exclusively of the other. For example, statistical models can potentially provide a distribution of important input parameters for some process-based models. Further, we suggest that implementation of monitoring networks - both atmospheric and surface water - at spatial and temporal scales appropriate for model calibration is critical to the success of either separate or integrated statistical and process-based modeling approaches.
|
|
| PRESENTATION |
Meeting in New Orleans: An Assessment of the Fate of Metal Oxide Nanomaterials in Porous Media |
04/07/2008
|
|
|
|
LOUX, N. T. AND N. SAVAGE. Meeting in New Orleans: An Assessment of the Fate of Metal Oxide Nanomaterials in Porous Media. Presented at American Chemical Society National Meeting, New Orleans, LA, April 06 - 10, 2008.
|
| Abstract:
|
This work assesses potential aqueous environmental metal oxide nanomaterial self-aggregation through the application of recent developments in surface complexation theory with historical DLVO procedures. Findings include: 1) nanomaterials with a Hamaker constant as large as 1E-19 J (and an absolute surface potential < 25 mV) will likely aggregate in most environmental aquatic media, 2) natural organic matter coatings may render metal oxide nanomaterials less likely to aggregate in aquatic media, 3) nanomaterials in aqueous suspension will likely have an absolute surface potential less than their micron-sized counterparts of the same composition, and 4) robust diffuse layer model databases of intrinsic surface site reactivity constants with multivalent aqueous environmental ions will need to be developed to provide accurate estimates of the surface potential of nanoparticles suspended in aqueous environmental systems.
|
|
| PRESENTATION |
Gender and Species-Mediated Differences in the in Vitro Metabolism of Triadimefon By Rodent Hepatic Microsomes |
03/16/2008
|
|
|
|
Ritger, S., J. F. KENNEKE, C. S. MAZUR, W. M. HENDERSON, AND J. Fisher. Gender and Species-Mediated Differences in the in Vitro Metabolism of Triadimefon By Rodent Hepatic Microsomes. Presented at Society of Toxicology Annual Meeting, Seattle, WA, March 16 - 20, 2008.
|
| Abstract:
|
Understanding how metabolism kinetics differ between genders and species is important in developing informative pharmacokinetic models and accurately assessing risk. Metabolism of the conazole fungicide Triadimefon (TDN) was studied in hepatic microsomes of SD rats and CD-1 mice. Michaelis-Menten saturation kinetic parameters were calculated using both substrate depletion and product formation reaction velocities. For values calculated from substrate depletion data, male rat microsomes were found to metabolize TDN most rapidly. Differences in stereoselectivity of TDN metabolism were also addressed by measuring changes in the enantiomeric ratio with respect to time. These data indicate a need to further investigate differences in metabolic kinetics and mechanisms between species and genders of model organisms in order to develop more accurate pharmacokinetic models for risk assessment.
|
|
| PRESENTATION |
Hspf Toolkit: A New Tool for Stormwater Management at the Watershed Scale |
06/22/2008
|
|
|
|
MOHAMOUD, Y. M., R. S. PARMAR, K. L. WOLFE, AND J. N. CARLETON. Hspf Toolkit: A New Tool for Stormwater Management at the Watershed Scale. Presented at Sustainability 2008 - Green Practices for the Water Environment Conference, National Harbor, MD, June 22 - 25, 2008.
|
| Abstract:
|
The Hydrological Simulation Program - FORTRAN (HSPF) is a comprehensive watershed model endorsed by US EPA for simulating point and nonpoint source pollutants. The model is used for developing total maximum daily load (TMDL) plans for impaired water bodies; as such, HSPF is the core watershed model in the US EPA BASINS (Better Assessment Science for Integrating Point and Nonpoint Sources) modeling framework. It characterizes the entire landscape of a watershed into pervious land (PERLAND), impervious land (IMPLND), and receiving surface waters (RECHRES). Its representation of land use is a feature that makes the model highly suitable for modeling streamflow and water quality for watersheds with mixed land uses. HSPF simulates streamflow as the sum of surface, interflow, and baseflow at user-defined temporal and spatial scales. It also simulates water quality constituents including sediment, pathogens (fecal coliform, etc.), pesticide chemicals, nutrients (nitrogen and phosphorus), tracers (chloride, bromide, dyes, etc.), carbon dioxide, inorganic carbon, zooplankton, phytoplankton, benthic algae, organic carbon, BOD, DO, pH, and alkalinity at user-defined scales. Our objective is to address HSPF limitations especially its limited capability to model urban watersheds with storm sewer networks and best management practices (BMPs), which are needed as part of low impact development (LID) promoted by many local jurisdictions. To meet these modeling challenges, stormwater management models must not only simulate the mitigation effects of detention-based BMPs, but also the effects of infiltration-based BMPs that support LID requirements and control runoff at the source. We developed a web-based toolkit for HSPF to address these stormwater modeling limitations and, in this presentation, we will discuss these enhanced HSPF capabilities.
|
|
| PRESENTATION |
Water, Water Everywhere, but Is It Safe to Drink? |
04/06/2008
|
|
|
|
RICHARDSON, S. D. Water, Water Everywhere, but Is It Safe to Drink? Presented at American Chemical Society Awards Presentation, New Orleans, LA, April 06 - 10, 2008.
|
| Abstract:
|
Drinking water disinfection by-products (DBPs) have been associated with adverse human health effects, including bladder cancer, early term miscarriage, and birth defects. While it is vitally important to kill harmful pathogens in water, it is also important to minimize harmful chemicals formed. Despite more than 30 years of research on DBPs, it is currently not known which DBPs are responsible for the human health effects. To this end, our research group has used mass spectrometry to uncover more than 300 DBPs that were not previously known. We have also linked with toxicologists to determine which may be responsible for the human health effects observed, and have investigated DBPs formed by alternative disinfectants that are increasing in use. What we currently know, and what we still hope to learn will be presented.
|
|
| PRESENTATION |
Formation Kinetics of Aqueous Suspensions of Fullerenes:Meeting in New Orleans. |
04/07/2008
|
|
|
|
MA, X. AND D. BOUCHARD. Formation Kinetics of Aqueous Suspensions of Fullerenes:Meeting in New Orleans. Presented at American Chemical Society National Meeting, New Orleans, LA, April 06 - 10, 2008.
|
| Abstract:
|
Stable colloidal suspension of C60 is commonly achieved through various solvent exchange techniques. Nevertheless, the additives such as tetrahydrofuran may be retained in the C60 aggregates, which may influence the surface properties of the suspension. In this study, colloidal suspensions of C60, C70 and a derivative of C60, PCBM ([6,6]-Phenyl C61-butyric acid methyl ester) were produced by extended mixing with water. This method is more environmentally relevant since it represents the behavior of nanomaterials in natural systems. We examined the contribution of background solution chemistry (pH, ionic strength) on the formation kinetics of colloidal suspensions in terms of mass, size and surface charge (zeta potential). These parameters are also compared between free-settling and filtered treatments.
|
|
| PRESENTATION |
Extraction and Analysis of C60, C70 and Pcbm in Aqueous Suspensions |
04/07/2008
|
|
|
|
BOUCHARD, D. AND X. MA. Extraction and Analysis of C60, C70 and Pcbm in Aqueous Suspensions. Presented at American Chemical Society National Meeting, New Orleans, LA, April 06 - 10, 2008.
|
| Abstract:
|
The goal of this work is to develop sampling and analytical methodologies for extracting and quantifying fullerenes in aqueous colloidal suspensions. Sampling and analysis of colloidal suspensions pose some unique challenges not encountered when working with true solutions. For example, sampling and analysis of aqueous fullerene suspensions is made problematic by the difficulty of preparing a standard suspension of known analyte concentration. As a result, extraction recoveries can be best determined through exhaustive extraction to determine total analyte mass in suspension.
|
|
| PRESENTATION |
Environmental Tools and Radiological Assessment |
01/29/2008
|
|
|
|
PURUCKER, S. T. Environmental Tools and Radiological Assessment. Presented at European Union PROTECT Working Group, Oslo, NORWAY, January 28 - 29, 2008.
|
| Abstract:
|
This presentation details two tools (SADA and FRAMES) available for use in environmental assessments of chemicals that can also be used for radiological assessments of the environment. Spatial Analysis and Decision Assistance (SADA) is a Windows freeware program that incorporates tools from environmental assessment for effective problem-solving. SADA includes integrated modules for GIS, visualization, geospatial analysis, statistical analysis, human health and ecological risk assessment, cost/benefit analysis, sampling design, and decision support. SADA is engineered with an open and highly scaleable environment that allows additional functionality without increase in complexity. The result is a mature infrastructure with considerable capabilities in data management, visualization, statistics, GIS functionality, input/output, and self-documentation for assessment of contaminated sites. Multimedia, Multi-pathway, Multi-receptor Exposure and Risk Assessment (3MRA) technology provides the ability to conduct screening-level risk-based assessment of potential human and ecological health impacts resulting from long term (chronic) exposure to hazardous chemicals released from land-based waste management units (WMUs). The 3MRA integrated modeling system consists of a set of 17 science model components with various post-processing capabilities. 3MRA resides within an underlying modeling system infrastructure called FRAMES. The FRAMES (Framework for Risk Analysis in Multimedia Environmental Systems) modeling infrastructure provides a solid foundation for integrating regulatory support decision tools and provides significant sensitivity and uncertainty analysis capabilities.
|
|
| PRESENTATION |
Benthic Macroinvertebrate Assemblages and Environmental Correlates in Springs of the Ridge and Valley Province |
04/17/2008
|
|
|
|
RASHLEIGH, B. Benthic Macroinvertebrate Assemblages and Environmental Correlates in Springs of the Ridge and Valley Province. Presented at Association of Southeastern Biologists Meeting, Greenville, SC, April 16 - 19, 2008.
|
| Abstract:
|
Springs are unique features in the landscape that provide important habitat for benthic invertebrates, yet there are few studies characterizing the distribution of benthic macro invertebrates in springs. Benthic macroinvertebrate and water quality data were collected at 35 springs in the Ridge and Valley region of the upper Tennessee River basin. Benthic macroivertebrate taxa comprised 75 familes, most occurring in the orders of Trichoptera and Diptera. The number of familes per site ranged from 10-26. Classification tree analysis of benthic macroivertebrate data identified five groups of springs based on elevation, conductivity, temperature, and coliform bacteria. High
elevation and oxygen favored diversity especially in the Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa. Springs with higher temperature and pollutants support more families within Coleoptera and Odonata. These findings for spring ecosystems can guide future assessments of springs in the Southeastern region.
|
|
| PRESENTATION |
Fishing for Novel Approaches to Ecosystem Service Forecasts |
07/13/2008
|
|
|
|
MCGARVEY, D. J. Fishing for Novel Approaches to Ecosystem Service Forecasts. Presented at Society for Conservation Biology 2008 Annual Meeting, Chattanooga, TN, July 13 - 17, 2008.
|
| Abstract:
|
The ecosystem service concept provides a powerful framework for conserving species and the environments they depend upon. Describing current distributions of ecosystem services and forecasting their future distributions have therefore become central objectives in many conservation and management efforts. For example, the U.S. Environmental Protection Agency (EPA) is currently testing methods that will allow it to forecast the productivity of multiple inland and estuarine fisheries, and to anticipate their associated services. One approach within EPA is to combine independently developed models of water quality, physical habitat, and fish production within a common computing environment, and to use the linked systems to assess a variety of alternative futures scenarios. This mechanistic, integrated approach facilitates rigorous sensitivity and uncertainty analyses, but its applicability is constrained by the data-intensive parameterization process. Alternatively, a pattern-based, macroecological strategy is being used to characterize fisheries at broad spatial and temporal scales. This empirical approach is less powerful than the mechanistic one, but can be readily implemented in any area of interest with existing, national-coverage datasets. To illustrate the benefits, tradeoffs, and mechanics of the latter method, I present a fisheries services model of the Albemarle-Pamlico River System in eastern Virginia and North Carolina (USA).
|
|
| PRESENTATION |
Risk Reduction from Minimization of Persistent, Bioaccumulative, and Toxic Waste Materials Within the U.S. Industrial Solid Waste Management System |
10/01/2008
|
|
|
|
BABENDREIER, J. E. Risk Reduction from Minimization of Persistent, Bioaccumulative, and Toxic Waste Materials Within the U.S. Industrial Solid Waste Management System. Presented at 1st International Conference on Hazardous Waste Management, Chania, GREECE, October 01 - 03, 2008.
|
| Abstract:
|
This study addressed three questions of interest in national-scale solid and hazardous waste management decision-making within the United States: 1) can we quantify the reduction in risk to human and ecological receptors resulting from the reduction of certain industrial waste streams containing select Waste Minimization Priority Chemicals (WMPC) that are persistent, bioaccumulative, and toxic; 2) can we address uncertainty in developing such a performance metric; and 3) more generally, can we quantify a protective national-scale “exit-level” threshold concentration that would establish the ability to safely manage low-level hazardous waste streams in less expensive, non-hazardous industrial waste management facilities?
|
|
| PRESENTATION |
Identifying Sources of Fecal Contamination in Streams Associated With Chicken Farms |
06/02/2008
|
|
|
|
Lee, Y., M. MOLINA, J. D. Willis, J. W. SANTO-DOMINGO, AND J. LU. Identifying Sources of Fecal Contamination in Streams Associated With Chicken Farms. Presented at 108th General Meeting of the American Society of Microbiology , Boston, MA, June 01 - 05, 2008.
|
| Abstract:
|
Poultry is responsible for 44% of the total feces production in the U.S., followed by cattle and swine. The large U.S. production of feces poses a contamination risk for affected watersheds across the country. To aid in the identification of the sources of contamination, many DNA-based, source-specific identifiers have been developed including recently developed chicken-specific metagenome-based markers. The objective of this study was to evaluate transport of chicken fecal material from manure-fertilized pastures into adjacent streams. Further, we used additional source-specific identifiers to track other sources of fecal contamination (cattle, human and wildlife).
|
|
| PRESENTATION |
Comparative Analysis of River Conservation in the United States and South Africa |
07/13/2008
|
|
|
|
RASHLEIGH, B., D. Roux, P. J. Ashton, AND N. Brajevich. Comparative Analysis of River Conservation in the United States and South Africa. Presented at Society for Conservation Biology 2008 Annual Meeting, Chattanooga, TN, July 13 - 17, 2008.
|
| Abstract:
|
Both the United States and South Africa are recognized for their strong and innovative approaches to the conservation of river ecosystems. These national programs possess similar driving legislation and ecoregional classification schemes supported by comprehensive monitoring programs. Strengths of the South African system include management based on watershed boundaries, specific conservation targets, and a strong consideration of the role of instream flows and connectivity. Comparative strengths of the U.S. program include the involvement of nonprofit and volunteer organizations, the use of modeling and causal analysis to support the setting of conservation objectives, and extensive efforts directed at stream restoration and species reintroduction. These complementary strengths provide opportunities for cooperative improvement of both systems. As the future threats of climate change, invasive species, and water pollution exert increasingly adverse effects on aquatic resources in both countries, it will be necessary for programs to share ideas and learn from each other's experiences, so that national freshwater conservation objectives are both achievable and sustainable.
|
|
| PRESENTATION |
Simulating Runoff from a Grid Based Mercury Model: Flow Comparisons |
07/06/2008
|
|
|
|
GOLDEN, H. E. AND C. D. KNIGHTES. Simulating Runoff from a Grid Based Mercury Model: Flow Comparisons. Presented at Computational Methods in Water Resources Conference, San Francisco, CA, July 06 - 10, 2008.
|
| Abstract:
|
Several mercury cycling models, including general mass balance approaches, mixed-batch reactors in streams or lakes, or regional process-based models, exist to assess the ecological exposure risks associated with anthropogenically increased atmospheric mercury (Hg) deposition, soil Hg concentrations, and consequent surface water fluxes. However, few mercury models exist at the scale of watersheds and include the coupling of processes involving multiple sources (atmospheric and terrestrial) and transformations of Hg, and watershed loading to surface water bodies. This is particularly important in large basins, where few mercury modeling studies have been conducted. We are refining a grid-based watershed Hg model (GBMM v2.0, Tetra Tech, 2006) that computes mass balances for hydrology, sediment, and mercury within each GIS raster grid cell and produces flux estimates of each to a tributary network.
|
|
| PRESENTATION |
A Macroecological Approach to Forecasting Fisheries Services: How Much Energy Does It Take to Catch a Fish? |
05/13/2008
|
|
|
|
MCGARVEY, D. J. AND J. M. JOHNSTON. A Macroecological Approach to Forecasting Fisheries Services: How Much Energy Does It Take to Catch a Fish? Presented at CAU/GFO Workshop: Ecosystem Services - Solution for Problems or a Problem that Needs Solution, Kiel, GERMANY, May 13 - 15, 2008.
|
| Abstract:
|
The U.S. Environmental Protection Agency is currently developing methods to quantify freshwater fisheries services (e.g., standing-stock abundance and/or biomass) at multiple spatial scales, and to forecast their future distributions. One approach uses linked, ecosystem process models (e.g., hydrologic dynamics, nutrient cycling, and density-dependant growth) to simulate fisheries responses to a suite of anthropogenic disturbances, such as land use changes and global climate change. This integrated methodology can generate robust predictions with known accuracy and precision (through sensitivity and uncertainty analyses), but is difficult to implement across regions, given the large datasets needed for model parameterization and validation. An alternative, macroecological approach capitalizes on first principles of aquatic ecosystem metabolism by estimating the total energy (i.e., in situ primary production plus allocthonous inputs) within a given system, then partitioning that energy among resident fish populations. This strategy is robust because all fish species have similar metabolic requirements, when considered on a per-unit-mass basis. The macroecological approach also requires relatively little a priori knowledge of environmental conditions or species’ life-histories; documented relationships between primary productivity and stressors of concern (e.g., the relationship between stream temperature and primary productivity), and basic information on regional species distributions are sufficient. It is therefore more flexible than the mechanistic modeling approach, and more amenable to regional and national-scale predictions. However, it is also a less powerful tool for predicting fisheries services at local-scales, with a high degree of precision. To demonstrate the advantages and limitations of the macroecological method, we present a series of current and future predictions, regarding fisheries services in the Albemarle-Pamlico River System of eastern Virginia and North Carolina (USA).
|
|
| PRESENTATION |
Integrated Disinfection By-Products Mixtures Research: Results from the Four Lab Study |
06/02/2008
|
|
|
|
RICHARDSON, S. D., J. E. SIMMONS, M. G. NAROTSKY, L. D. CLAXTON, E. S. HUNTER, R. J. MILTNER, J. G. PRESSMAN, T. F. SPETH, G. E. RICE, L. K. TEUSCHLER, S. W. Krasner, AND H. S. Weinberg. Integrated Disinfection By-Products Mixtures Research: Results from the Four Lab Study. Presented at 56th ASMS Conference on Mass Spectrometry, Denver, CO, June 01 - 05, 2008.
|
| Abstract:
|
This study involves collaboration of four national laboratories/centers of the U.S. Environmental Protection Agency (EPA), as well as scientists from universities and water utilities, and is termed the ‘Four Lab Study’. The purpose of this study is to address concerns related to potential health effects from exposure to complex mixtures of drinking water disinfection by-products (DBPs) that cannot be addressed directly from toxicological studies of individual DBPs or simple DBP mixtures. Adverse health effects evaluated in this study include the reproductive and developmental effects observed in some recent human epidemiologic studies of drinking water, as well as several other effects.
|
|
| PRESENTATION |
Integrated Monitoring, Modeling and Mapping for Managing and Valuing Bundled Services in the US – Ecosystem Services Research and Development at the EPA |
05/13/2008
|
|
|
|
JOHNSTON, J. M., A. C. NEALE, M. E. MCDONALD, K. Reckhow, AND D. Ames. Integrated Monitoring, Modeling and Mapping for Managing and Valuing Bundled Services in the US – Ecosystem Services Research and Development at the EPA. Presented at CAU/GFO Workshop: Ecosystem Services - Solution for Problems or a Problem that Needs Solution, Kiel, GERMANY, May 13 - 15, 2008.
|
| Abstract:
|
The Ecological Research Program (ERP) of the EPA Office of Research and Development has the vision of a comprehensive theory and practice for characterizing, quantifying, and valuing ecosystem services, and their relationship to human well-being for environmental decision making. This vision of future environmental decisionmaking is planned as an innovative, online decision support platform with a full range of data exploration methods, models and decision options, and is intended to be a dynamic connection between managers and policy developers and their ecosystems and bundled services of interest, from local to regional and national scales. Essential to the success of this ambitious goal is the application of systems thinking that is both structured and comprehensive.
|
|
| PRESENTATION |
Ecosystem Services and Environmental Decision-Making |
01/31/2008
|
|
|
|
PURUCKER, S. T. Ecosystem Services and Environmental Decision-Making. Presented at Seminar at the Swedish Geotechnical Institute, Goteborg, SWEDEN, January 31, 2008.
|
| Abstract:
|
Presentation on ecosystem services and environmental decision-making.
|
|
| PRESENTATION |
Spatial Approaches for Ecological Screening and Exposure Assessment of Chemicals and Radionclides |
01/29/2008
|
|
|
|
PURUCKER, S. T. Spatial Approaches for Ecological Screening and Exposure Assessment of Chemicals and Radionclides. Presented at European Union PROTECT Working Group, Oslo, NORWAY, January 29, 2008.
|
| Abstract:
|
This presentation details a tool, SADA, available for use in environmental assessments of chemicals that can also be used for radiological assessments of the environment. Spatial Analysis and Decision Assistance (SADA) is a Windows freeware program that incorporates tools from environmental assessment for effective problem-solving. SADA includes integrated modules for GIS, visualization, geospatial analysis, statistical analysis, human health and ecological risk assessment, cost/benefit analysis, sampling design, and decision support. SADA is engineered with an open and highly scaleable environment that allows additional functionality without increase in complexity. The result is a mature infrastructure with considerable capabilities in data management, visualization, statistics, GIS functionality, input/output, and self-documentation for assessment of contaminated sites.
|
|
| PRESENTATION |
2008 Meeting in Germany: Emerging Environmental Contaminants and Current Issues |
04/14/2008
|
|
|
|
RICHARDSON, S. D. 2008 Meeting in Germany: Emerging Environmental Contaminants and Current Issues. Presented at 2nd International Symposium on Genotoxicity in Aquatic Systems: Causes, Effects and Regulatory Needs, Dessau, GERMANY, April 14 - 16, 2008.
|
| Abstract:
|
This presentation will discuss emerging environmental contaminants that are currently of concern to the U.S. EPA and to other agencies. Emerging contaminants include drinking water disinfection by-products (DBPs), perfluorinated chemicals, pharmaceuticals, flame retardants, benzotriazoles, gasoline additives, pesticide degradation products, sunscreens/UV filters, and algal toxins. Emerging DBPs include iodo¬acids, iodo-trihalomethanes, bromonitromethanes, haloamides, and nitrosamines (including nitrosodimethylamine, NDMA). New toxicological research is revealing that some of these emerging DBPs are more genotoxic and cytotoxic than DBPs currently regulated, and the use of newer alternative disinfectants (chloramines, ozone, chlorine dioxide) can increase their formation.
|
|
| PRESENTATION |
Meeting in Canada: Chlorinated Vs. Chloraminated Drinking Water: Toxicity-Based Identification of Disinfection By-Products Using Esi-MS and Esi-MS/MS |
05/27/2008
|
|
|
|
RICHARDSON, S. D., F. G. CRUMLEY, F. Fasano, M. J. Plewa, E. D. Wagner, T. H. Mize, P. Angel, R. Orlando, L. N. Williamson, AND M. G. Bartlett. Meeting in Canada: Chlorinated Vs. Chloraminated Drinking Water: Toxicity-Based Identification of Disinfection By-Products Using Esi-MS and Esi-MS/MS. Presented at Canadian Society of Chemistry Conference, Edmonton, AB, CANADA, May 27 - 29, 2008.
|
| Abstract:
|
Drinking water disinfection by-products (DBPs) are of concern because epidemiologic studies have shown that they are associated with bladder cancer and adverse reproductive/developmental effects in human populations. There is almost no information on high molecular weight DBPs (> 1000 Da), which are indicated to comprise >50% of the total organic halogen from chlorinated drinking water. We used a bioassay directed approach to focus identification work on the most toxicologically important DBPs. To this end, drinking water was collected from full-scale treatment plants that use chlorine or chloramines as disinfectants, and this drinking water was fractionated initially according to molecular size (through the use of ultrafiltration membranes). Mammalian cell acute genotoxicity and cytotoxicity assays were used to determine the toxicity of the fractions, and electrospray ionization (ESI)-mass spectrometry (MS) and ESI-MSIMS were used to obtain structural information on the DBPs in those fractions. Genotoxicity results of the molecular weight fractions of chlorinated and chloraminated water revealed the <1K Da fraction to be the most genotoxic. The cytotoxicity and genotoxicity of the >5K Da fraction was the least toxic.
|
|
| PRESENTATION |
Bromine Incorporation in Regulated and Emerging DBPs and the Relative Predominance of Mono, Di, and Trihalogenated DBPs |
11/16/2008
|
|
|
|
Krasner, S. W., T. Lee, R. Chinn, H. Weinberg, N. Bodin, S. D. RICHARDSON, J. G. PRESSMAN, T. F. SPETH, R. J. MILTNER, AND J. E. SIMMONS. Bromine Incorporation in Regulated and Emerging DBPs and the Relative Predominance of Mono, Di, and Trihalogenated DBPs. Presented at AWWA Water Quality Technology Conference and Exposition, Cincinnati, OH, November 16 - 20, 2008.
|
| Abstract:
|
Brominated disinfection by-products (DBPs) (in general) appear to be more cytotoxic and genotoxic than the chlorinated species, and some of the dihalogenated species are more toxic than the trihalogenated analogues; however, many of the more toxic species are not routinely measured. The primary objective of this presentation is an examination of bromine incorporation in emerging DBPs versus that of the regulated DBPs and a secondary objective is the study of the predominance of di- versus trihalogenated species in these different DBP classes, in order to better understand and characterize exposure to DBPs of health concern. Occurrence data on emerging halogenated DBPs of health concern from nationwide studies are being evaluated. Specific DBPs that are being studied include 4 regulated trihalomethanes (THMs), 9 bromine- and chlorine-containing haloacetic acids (HAAs), 2 mono- and 3 dihaloacetonitriles (HANs), 3 dihalo- and 4 trihalonitromethanes (HNMs), 3 dihalo- and 4 trihaloacetaldehydes (HAs), and selected bromine- and chlorine-containing haloketones and haloacetamides.
|
|
| PRESENTATION |
Preventing Pollution from Biofuels Through a Knowledge Based Approach to Composition and Transport |
05/20/2008
|
|
|
|
WEAVER, J. W., M. Tonkin, E. J. HAYTER, H. WHITE, N. NICHOLS, L. DEHAVEN, M. SMALL, L. R. EXUM, D. L. SPIDLE, D. COLON, AND L. M. PRIETO. Preventing Pollution from Biofuels Through a Knowledge Based Approach to Composition and Transport. Presented at EPA Science Forum, Washington, DC, May 20 - 22, 2008.
|
| Abstract:
|
The US has been subject to unexpected and costly fuel-related contamination problems. The composition, properties and behavior of fuels in the environment is problematic because they are composed of hundreds of compounds of varying chemical types. Consequently a comprehensive two-pronged program to study their behavior has been developed. The first prong is to study the composition and properties of representative fuels and biofuels nationally in measurements taken from around the country; and historically to see how fuel composition has changed over the years. This study is important to the problem of subsurface contamination as underground releases are not generally detected until years after their occurrence. The second prong of this work is focused on transport of these contaminants in surface and ground waters. Whereas previously, single components such as benzene were the primary focus, a more comprehensive approach is needed to assess contemporary fuels because plume travel and transformation of one component (i.e., benzene) depends on the presence, transport and transformation of other fuel components. Similar problems may be encountered in surface waters for biofuels where phase separation of ethanol blends may create oil slicks while generating large volumes of alcohol-water mixtures. Surface and ground water transport models are being modified to use compositional data for biofuels. In the subsurface, the Hydrocarbon Spill Screening Model is being merged with MODFLOW and MT3D for transport calculations. For surface waters, the EPA Research Object-Oriented Oil Spill Model is being merged with the Environmental Fluid Dynamics Code (EFDC) for analogous problems.
|
|
| PRESENTATION |
Virtual Beach: Decision Support Tools for Beach Pathogen Prediction |
05/20/2008
|
|
|
|
WOLFE, K. L., W. E. FRICK, R. G. ZEPP, M. MOLINA, AND M. J. CYTERSKI. Virtual Beach: Decision Support Tools for Beach Pathogen Prediction. Presented at EPA Science Forum, Washington, DC, May 20 - 22, 2008.
|
| Abstract:
|
The Virtual Beach Managers Tool (VB) is decision-making software developed to help local beach managers make decisions as to when beaches should be closed due to predicted high levels of water borne pathogens. The tool is being developed under the umbrella of EPA's Advanced Monitoring Initiative (AMI) and in support of the Beaches Environmental Assessment and Coastal Health (BEACH) Act. AMI is an EPA initiative that advances the goals of integrating science and environmental data into decision support tools useful to policy makers and individuals. Virtual Beach is comprised of two components. The first is a data exploration/model builder tool that facilitates the development of a multiple linear regression (MLR) equation for predicting pathogen concentrations for a specific beach based on environmental data such as wave height and water temperature. The second component is a Beach Manager tool that is deployed for use by local beach officials. It houses the MLR developed with the model builder, automatically pulls in distributed data for the current day, and makes a prediction to aid local officials in deciding whether a beach should be closed for a particular day. VB should benefit the beach going public by keeping the beaches open on more days when they are safe, and protecting them more frequently when water quality drops below acceptable levels. The testing and deployment of VB is possible through collaboration between the Office of Water, Region 5 and several Great Lake States and organizations.
|
|
| PRESENTATION |
Data for Environmental Modeling (D4em): Background and Applications of Data Automation |
05/20/2008
|
|
|
|
WOLFE, K. L., R. S. PARMAR, G. F. LANIAK, A. B. Parks, L. Wilson, J. E. Brandmeyer, D. P. Ames, AND M. H. Gray. Data for Environmental Modeling (D4em): Background and Applications of Data Automation. Presented at EPA Science Forum, Washington, DC, May 20 - 22, 2008.
|
| Abstract:
|
The Data for Environmental Modeling (D4EM) project demonstrates the development of a comprehensive set of open source software tools that overcome obstacles to accessing data needed by automating the process of populating model input data sets with environmental data available from distributed data sources. Among the obstacles still remaining are: locating sources of data, querying the data sources, understanding various access protocols, and converting data from native to model specific formats. Data management and geoprocessing components included in D4EM allow for complex data transformations. Geoprocessing operations are implemented through linkages with open source GIS software.
|
|
| PRESENTATION |
U.S. EPA High-Field Nmr Facility With Remote Accessibility |
05/20/2008
|
|
|
|
TENG, Q., D. R. EKMAN, W. Huang, W. M. HENDERSON, AND T. W. COLLETTE. U.S. EPA High-Field Nmr Facility With Remote Accessibility. Presented at EPA Science Forum, Washington, DC, May 20 - 22, 2008.
|
| Abstract:
|
EPA’s High-Field Nuclear Magnetic Resonance Research Facility housed in Athens, GA has two Varian 600 MHz NMR spectrometers used for conducting sophisticated experiments in environmental science. Off-site users can ship their samples and perform their NMR experiments remotely from their desktops via secure internet connection.
In collaboration with other Divisions in ORD/NERL, ORD/NHEERL, ORD/NCCT, various other Federal labs (PNNL, NIH/NCI, US Army Corp of Engineers), several Universities (UGA, UF, OGI, Purdue), and industry (Dow Chemical), the initial focus of the facility is metabolomics research to improve chemical exposure assessments, and structure biology research The facility is an ORD-wide resource, and we are inviting all EPA investigators to consider using the state-of-the-art NMR instrumentation in their work. After completing training provided by ERD researchers, any EPA scientist may independently operate the NMR spectrometers either on-site or remotely. The facility also offers access to Dr. Teng’s broad expertise in NMR experimental design and data interpretation. Remote operation of the NMR spectrometers will be demonstrated at the Science Forum.
|
|
| PRESENTATION |
Differential Effects of Solar Ultraviolet Radiation on Culturable Enterococcus Faecalis and Enterococcus Dna Determined Using Real-Time Quantitative Pcr |
06/08/2008
|
|
|
|
ZEPP, R. G., E. M. WHITE, AND M. MOLINA. Differential Effects of Solar Ultraviolet Radiation on Culturable Enterococcus Faecalis and Enterococcus Dna Determined Using Real-Time Quantitative Pcr. Presented at 2008 ASLO Summer Meeting, St. John's, NL, CANADA, June 08 - 13, 2008.
|
| Abstract:
|
Biological contamination of aquatic environments by pathogenic microorganisms is often assessed using fecal indicator bacteria such as enterococci. The concentrations of enterococci are commonly determined by culturing techniques, but there has been recent interest in using molecular microbial analysis methods with shorter reporting times. The quantitative polymerase chain reaction (qPCR) applied to detect DNA concentrations of Enterococcus is one rapid technique that shows great promise for evaluating recreational water quality. Very little is known about factors that affect enterococci qPCR results in freshwater environments. Studies conducted near UV -disinfected effluents of sewage treatment plants typically indicate that the ratios of qPCR - to culture-determined concentrations of enterococci ranged up to several orders of magnitude. These results indicate that the sensitivity of these two indicators to solar ultraviolet (UV) radiation may be very different. In this paper we compare the effects of solar UV radiation on culturable Enterococcus faecalis with its effects on Enterococcus measured using real-time qPCR. As part of this study, we also report the effects of chromophoric dissolved organic matter (CDOM) and suspended sediments on the light-induced degradation of these indicators.
|
|
| PRESENTATION |
Meeting at Yale University: the Next Generation of Disinfection By-Products |
03/05/2008
|
|
|
|
RICHARDSON, S. D. Meeting at Yale University: the Next Generation of Disinfection By-Products. Presented at Seminar at Yale University, New Haven, CT, March 05, 2008.
|
| Abstract:
|
Slide presentation on drinking water disinfection by-products.
|
|
| PRESENTATION |
Virtual Beach Manager Toolset |
03/18/2008
|
|
|
|
WOLFE, K. L., W. E. FRICK, R. G. ZEPP, M. MOLINA, M. J. CYTERSKI, AND R. S. PARMAR. Virtual Beach Manager Toolset. Presented at 7th Annual Surface Water Monitoring and Standards Meeting (SWiMS), Chicago, IL, March 18 - 20, 2008.
|
| Abstract:
|
The Virtual Beach Manager Toolset (VB) is a set of decision support software tools developed to help local beach managers make decisions as to when beaches should be closed due to predicted high levels of water borne pathogens. The tools are being developed under the umbrella of EPA’s Advanced Monitoring Initiative (AMI) and in support of the Beaches Environmental Assessment and Coastal Health (BEACH) Act. AMI is an EPA initiative that advances the goals of integrating science and environmental data into decision support tools useful to policy makers and individuals.
|
|
| PRESENTATION |
Aggregation and Deposition of C60 in Aqueous Systems |
08/17/2008
|
|
|
|
MA, X. AND D. BOUCHARD. Aggregation and Deposition of C60 in Aqueous Systems. Presented at 236th ACS National Meeting & Exposition, Philadelphia, PA, August 17 - 21, 2008.
|
| Abstract:
|
The extremely low water solubility of many fullerenes precludes aqueous solution processing for engineering applications and minimizes the potential for fullerene environmental effects in aqueous environments. However, studies have shown that C60 fullerene can form stable colloidal suspensions in water that result in C60 aqueous concentrations many orders of magnitude above C60’s aqueous solubility. The effects of solution chemistry on the magnitude and kinetics of fullerene deposition will be explored. Atomic force microscopy (AFM) will also be used to probe the structure of aggregates deposited on QCM crystal surfaces. In addition, deposition under favorable and unfavorable conditions will be measured with the QCM to allow estimation of attachment efficiencies that will be compared with empirically derived measures from colloid transport studies using porous media columns.
|
|
| PRESENTATION |
An Update on U.S. Gasoline Composition |
03/13/2008
|
|
|
|
WEAVER, J. W. An Update on U.S. Gasoline Composition. Presented at 18th Annual AEHS Meeting and West Coast Conference on Soils, Sediments, and Water, San Diego, CA, March 10 - 13, 2008.
|
| Abstract:
|
There is no abstract for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
|
|
| PRESENTATION |
Meeting in Atlanta: An Update on U.S. Gasoline Composition |
03/19/2008
|
|
|
|
WEAVER, J. W. Meeting in Atlanta: An Update on U.S. Gasoline Composition. Presented at ASTWMO Meeting on MTBE and Other Fuel Additives, Atlanta, GA, March 17 - 20, 2008.
|
| Abstract:
|
There is no abstract for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
|
|
| PRESENTATION |
Do You Know What's in Your Drinking Water? Uncovering New Disinfection By-Products |
03/12/2008
|
|
|
|
RICHARDSON, S. D. Do You Know What's in Your Drinking Water? Uncovering New Disinfection By-Products. Presented at Seminar at Georgia College & State University, Milledgeville, GA, March 12, 2008.
|
| Abstract:
|
Slide presentation on drinking water disinfection by-products. There is no abstract for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
|
|
| PRESENTATION |
Framework for Optimizing the Evaluation of Data from Contaminated Soil in Sweden |
06/03/2008
|
|
|
|
Norman, J., S. T. PURUCKER, R. N. Stewart, P. Back, AND F. Engelke. Framework for Optimizing the Evaluation of Data from Contaminated Soil in Sweden. Presented at ConSoil 2008, Milan, ITALY, June 03 - 06, 2008.
|
| Abstract:
|
The Swedish guidelines for the evaluation of data for the purpose of a risk assessment at contaminated sites are of a qualitative character, as opposed to the USEPA’s Data Quality Objective Process. In Sweden, this can sometimes be a problem because the demands on data quality are unclear and often guided by the experience of the consultant or by the persons at the regulatory agency, rather than by national guidelines. A framework for evaluating data from contaminated sites is thus useful, both for consultants and for the regulatory agencies. Such a framework can facilitate not only a common ground for demands on data evaluation, but also a transparent and scientific basis for data evaluation where statistical methods and uncertainty analysis are in focus.
|
|
| PRESENTATION |
Spectroscopic and Photochemical Properties of Water-Soluble Fullerenol |
08/17/2008
|
|
|
|
Kong, L., O. Tedrow, AND R. G. ZEPP. Spectroscopic and Photochemical Properties of Water-Soluble Fullerenol. Presented at 236th ACS National Meeting & Exposition, Philadelphia, PA, August 17 - 21, 2008.
|
| Abstract:
|
Fullerenol, a hydroxylated form of C60-fullerene, is of potential environmental and biological significance due to its buckyball structure, hydroxyl groups and high water solubility. Although fullerenol is known to be an efficient triplet photosensitizer, little is known about its direct photoreactivity under environmental conditions. Spectroscopic properties including ultraviolet-visible absorption and fluorescence were examined, and fullerenol irradiation kinetics with simulated solar and monochromatic irradiation were investigated. The absorption coefficients of fullerenol decreased after irradiation, whereas the excitation-emission matrix fluorescence increased with the excitation/emission peak shifting to shorter wavelengths. The fluorescence quantum yields of fullerenol ranged from 0.00017 to 0.00041 over an excitation wavelength range of 300 to 410 nm. The direct photoreaction of fullerenol exhibited multi-stage kinetics with an initial quantum yield of 0.017 at an irradiation wavelength of 366 nm.
|
|
| PRESENTATION |
Gasoline Composition in 2008 |
03/18/2008
|
|
|
|
WEAVER, J. W., L. R. EXUM, AND L. M. PRIETO. Gasoline Composition in 2008. Presented at 20th Annual Tanks Conference, Atlanta, GA, March 17 - 19, 2008.
|
| Abstract:
|
Gasoline composition in the U.S is determined by factors related to crude oil source, refinery capacity, geography and regulatory factors. Major regulation derived from the Clean Air Act and its amendments determines the benzene and former oxygenate requirements for reformulated gasoline. These were specified on a county, partial county, or city basis. Reformulated gasoline has historically accounted for 1/3 of the total gasoline used in the country, but is prevalent in the most highly populated regions of the country, especially the Northeast corridor and California. The remainder of the country uses conventional gasoline, where the benzene content is limited by 1990 producer baselines. This gasoline may have more benzene than reformulated gasoline as seen in EPA/ORD and many other data sets. The Mobile Source Air Toxics Rule of 2007 will limit benzene content across the U.S. by 2011. The passage of the Energy Policy Act of 2005 caused ethers to be removed from the U.S. gasoline supply. Data from the Department of Energy document an abrupt shift in reformulated gasoline to reformulated gasoline made with alcohol. Current data show that benzene levels continue to be responsive to Clean Air Act mandates and that ethanol content can vary from 6% to 12% in both reformulated and conventional gasoline.
|
|
| PRESENTATION |
Development of Mass Spectrometric Ionization Methods for Fullerenes and Fullerene Derivatives |
08/17/2008
|
|
|
|
Isaacson, C., J. A. Field, AND D. BOUCHARD. Development of Mass Spectrometric Ionization Methods for Fullerenes and Fullerene Derivatives. Presented at 236th ACS National Meeting & Exposition, Philadelphia, PA, August 17 - 21, 2008.
|
| Abstract:
|
Currently investigations into the environmental behavior of fullerenes and fullerene derivatives is hampered by the lack of well characterized standards and by the lack of readily available quantitative analytical methods. Reported herein are investigations into the utility of matrix assisted laser desorption ionization, electrospray ionization, atmospheric pressure chemical ionization, fast atom bombardment, and atmospheric solids analysis probe (ASAP) for the ionization and analysis of fullerenes and fullerene derivatives by mass spectrometry. Most interestingly, ASAP analysis of aqueous fullerene aggregates generated by extended stirring in water produced ions corresponding to C60OxHy with x and y each being less than 7. This is the first reported observation of the functionalization of C60 upon extended stirring in water. Additionally, analysis of hydroxylated fullerene, C60 OH16-24 by ASAP or any other of the above mentioned ionization techniques only produced ions for C60 and no ions diagnostic of the hydroxylated species.
|
|
| PRESENTATION |
Characterizing Aqueous Fullerene Suspensions |
08/11/2008
|
|
|
|
BOUCHARD, D., X. MA, AND C. Isaacson. Characterizing Aqueous Fullerene Suspensions. Presented at National Environmental Monitoring Conference, Washington, DC, August 11 - 15, 2008.
|
| Abstract:
|
Over 500 products purporting to contain nanoscale materials were on the market in 2007 and projections have suggested that the market for nanomaterial-containing products could reach over $2 trillion by the year 2014. With the expected development, production, and use of nanomaterials, the need for further research on the transport and fate of nanomaterials in the environment has been recognized. Federal agencies and industry liaison groups have identified the key environmental, health, and safety research needs for engineered nanomaterials. One of the key research needs identified was the development of analytical methodology for characterizing nanomaterials in environmental matrices. In this study, aqueous fullerene suspensions were formed at pH's of 4, 7, and 10 in 10mM NaCl equivalent using the extended stirring technique, which does not employ organic solvents, as this technique is more representative of actual environmental conditions. Suspensions were also formed using ground and surface waters. The suspensions were then characterized for fullerene mass concentration, particle size, morphology, and surface potential (zeta potential). Fullerene mass concentration was determined by extracting the fullerenes from the aqueous phase using a liquid-liquid extraction procedure. Fullerenes in the extract were then separated and quantitated by HPLC-UV and HPLC-MS. Fullerene particle size analysis was achieved using dynamic light scattering, electrophoretic mobilities of fullerene aggregates were measured using laser Doppler velocimetry, and particle size and morphology were evaluated using atomic force microscopy (AFM) and transmission electron microscopy (TEM).
|
|
| PRESENTATION |
Meeting in Atlanta: Lead Scavengers in Old Product Samples: An EPA Evaluation |
03/19/2008
|
|
|
|
WEAVER, J. W. AND D. L. SPIDLE. Meeting in Atlanta: Lead Scavengers in Old Product Samples: An EPA Evaluation. Presented at ASTWMO Meeting on MTBE and Other Fuel Additives, Atlanta, GA, March 19, 2008.
|
| Abstract:
|
Slide presentation presented at the ASTWMO meeting on MTBE and other fuel additives on lead scavengers in old product samples.
|
|
| PRESENTATION |
Lead Scavengers in Old Product Samples: An EPA Evaluation |
03/17/2008
|
|
|
|
WEAVER, J. W. AND D. L. SPIDLE. Lead Scavengers in Old Product Samples: An EPA Evaluation. Presented at 20th Annual Tanks Conference, Atlanta, GA, March 17 - 19, 2008.
|
| Abstract:
|
Slide presentation presented at the 20th Annual Tanks Conference on lead scavengers in old product samples.
|
|
| PRESENTATION |
EPA ’s Ecological Models for Integrated Watershed Management |
05/20/2008
|
|
|
|
RASHLEIGH, B., M. C. BARBER, AND S. M. CORMIER. EPA ’s Ecological Models for Integrated Watershed Management. Presented at 2008 National Monitoring Conference, Atlantic City, NJ, May 18 - 22, 2008.
|
| Abstract:
|
Aquatic ecological populations and communities are affected by the nature and quality of the water in which they live. Specific factors that affect instream biota include chemical variables, biotic interactions, energy source, flow regime, and habitat structure. As watershed management becomes more holistic and comprehensive, managers have become increasingly interested in the dynamics and functioning of the aquatic ecosystem and the relation of landscape processes to aquatic endpoints. The U.S. EPA has developed multiple modeling and decision support approaches to allow monitoring data to be used to support these more comprehensive questions. Three of these approaches, CADDIS, BASS, and AQUATOX, are most useful in integrated watershed management.
|
|
| PRESENTATION |
Mechanistic Investigation of the Non-Cytochrome P450 Mediated Metabolism of Triadimefon and Implications for Toxicity |
06/01/2008
|
|
|
|
KENNEKE, J. F., C. S. MAZUR, S. E. Ritger, AND T. SACK. Mechanistic Investigation of the Non-Cytochrome P450 Mediated Metabolism of Triadimefon and Implications for Toxicity. Presented at 4th Pan Pacific Conference on Pesticide Science, Honolulu, HI, June 01 - 05, 2008.
|
| Abstract:
|
Triazole containing compounds have been used for decades as agricultural and medicinal fungicides. Recently, emphasis has been placed on the potential adverse effects of these compounds within mammalian systems and an effort has been made to understand their toxic mode of action. Triadimefon is a triazole fungicide used on turf grasses, shrubs and agricultural products including pineapples. It is classified as a possible human carcinogen and the U.S. Environmental Protection Agency (EPA) has concluded that it does not share a common mechanism of toxicity with other triazole fungicides. We postulate that one reason for this difference is that while many triazole fungicides are metabolized via an oxidative cytochrome P450 (CYP)-mediated pathway, triadimefon is not. Results from specific enzyme inhibitor and pure enzyme studies indicated that the microsomal short-chain dehydrogenase/reductase, 11B-hydroxysteroid dehydrogenase type1 (11B-HSD1), mediated the stereoselective carbonyl reduction of triadimefon to yield triadimenol. Additionally, hexose-6-phosphate dehydrogenase (H6PDH) was found to be indirectly involved in triadimefon metabolism by acting as a source of NADPH for 11B-HSD1. These results ultimately associate xenobiotic metabolism with both steroidogenesis (i.e., the physiological role of 11B-HSD1 is glucocorticoid regulation) and carbohydrate metabolism (i.e., H6PDH is involved in the pentose phosphate pathway). Considering the impact of triadimefon on these biochemical pathways may help explain some of triadimefon’s unique toxicological effects relative to other triazole fungicides.
|
|
| PRESENTATION |
Meeting at Temple University: An Update on U.S. Gasoline Composition |
04/08/2008
|
|
|
|
WEAVER, J. W. Meeting at Temple University: An Update on U.S. Gasoline Composition. Presented at Temple University Civil Engineering Graduate Seminar, Philadelphia, PA, April 08, 2008.
|
| Abstract:
|
There is no abstract for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.
|
|
| PRESENTATION |
Fecal Indicator Bacteria and Environmental Observations: Validation of Virtual Beach |
06/29/2008
|
|
|
|
WHITE, E. M., R. G. ZEPP, M. MOLINA, K. L. WOLFE, AND W. E. FRICK. Fecal Indicator Bacteria and Environmental Observations: Validation of Virtual Beach. Presented at Gordon Research Conference on Oceans & Human Health, Tilton, NH, June 29 - July 04, 2008.
|
| Abstract:
|
Contamination of recreational waters by fecal material is often assessed using indicator bacteria such as enterococci. Enumeration based on culturing methods can take up to 48 hours to complete, limiting the accuracy of water quality evaluations. Molecular microbial techniques employing the quantitative polymerase chain reaction (qPCR) show great promise due to shorter reporting times. However, decision makers need additional tools to predict pathogen exposure and identify sources of contamination at beaches. We are currently conducting studies at several beach sites to validate the empirical modeling component of the Virtual Beach software. This modeling tool has been developed to provide beach managers with early warnings of bacterial levels that pose health risks. Bacterial concentrations can be highly dynamic in response to a number of environmental factors including meteorological conditions, hydrodynamics, solar irradiance, and water chemistry. Current studies involve concurrent measurements of microbial levels and environmental observations at the beaches. The data will be used with the Virtual Beach software to develop statistical models that nowcast and forecast microbial levels. Preliminary findings will be presented. Laboratory studies investigating the role of ultraviolet (UV) radiation on the fate of culturable and qPCR-determined enterococci will also be reported, including the effects of chromophoric dissolved organic matter (CDOM) and suspended sediments. Results indicate that the sensitivity of enterococci DNA and whole cells to UV radiation may be very different.
|
|
| PRESENTATION |
Calculating Henry’s Constants of Charged Molecules Using Sparc |
08/17/2008
|
|
|
|
Ayyampalayam, S. N., S. H. HILAL, AND L. Carreira. Calculating Henry’s Constants of Charged Molecules Using Sparc. Presented at 236th ACS National Meeting & Exposition, Philadelphia, PA, August 17 - 21, 2008.
|
| Abstract:
|
SPARC Performs Automated Reasoning in Chemistry is a computer program designed to model physical and chemical properties of molecules solely based on thier chemical structure. SPARC uses a toolbox of mechanistic perturbation models to model intermolecular interactions. SPARC has implemented a Henry’s constant calculator for neutral molecules using existing vapor pressure and activity models. The problems associated with modeling Henry’s constants for charged molecules is the lack of sufficient data required to train and develop the required parameters to represent the charged group. In this project we have developed a reliable model with less parameterization to model the interaction of the monopole with the solvent. The importance of calculating the Henry’s constant is its utility in modeling the gas pKa, non-aqueous pKa, log Kow of charged species, and log D. This modeling concept has been applied to calculate the single proton transfer energy in various solvents and is used in modeling gas and non-aqueous pKa in SPARC.
|
|
| PRESENTATION |
Organophosphorus (Op) Pesticide Degradation in the Presence of Chlorinated Oxidants: Kinetics, Modeling, and Structure-Activity Relationships |
06/22/2008
|
|
|
|
DUIRK, S. E., L. M. Desetto, AND G. M. Davis. Organophosphorus (Op) Pesticide Degradation in the Presence of Chlorinated Oxidants: Kinetics, Modeling, and Structure-Activity Relationships. Presented at Gordon Research Conference, Environmental Sciences: Water, Holderness, NH, June 22 - 27, 2008.
|
| Abstract:
|
The rates and pathways for pesticide transformation during drinking water treatment are known for only a few pesticides and under limited conditions. The resulting oxons are more toxic than the parent pesticides. The transformation rates and pathways for chlorpyrifos, an OP pesticide, have been established in buffered deionized water and in the presence of naturally occurring aquatic constituents. However, it has not been established how the OP pesticides react in the presence of chlorinated oxidants as a class of pesticides. The objective of this work is to investigate OP pesticide transformation pathways as a class in the presence of aqueous chlorine and chloramines. Eight priority OP pesticides from two subgroups will be examined for their reactivity with chlorinated oxidants: phosphorothioate subgroup (chlorethoxyfos, chlorpyrifos, parathion, diazinon, tebupirimfos) and phosphorodithioate subgroup (malathion, methidathion, and phosmet). These OP pesticides were selected for their use patterns as well as their diverse structures and chemical properties. Experimental results will be used to determine intrinsic rate coefficients and model the reaction between chlorine/chloramine and OP pesticides. Molecular descriptors will be used to correlate reactivity with chlorinated oxidants to OP structural characteristics. Structure-activity relationships and models will aid regulators in determining the risk associated with drinking potable water contaminated with a mixture of pesticides that elicit a common mode of toxicity.
|
|
| PRESENTATION |
Ecosystem Services of Rivers |
05/03/2008
|
|
|
|
RASHLEIGH, B. Ecosystem Services of Rivers. Presented at 2008 National River Rally, Huron, OH, May 02 - 05, 2008.
|
| Abstract:
|
Presentation on ecosystem services of rivers for the National River Rally, May 2008, in Huron, OH.
|
|
| PRESENTATION |
The Response of Fish Habitat to Environmental Flows in the Albemarle-Pamlico Watershed |
10/27/2008
|
|
|
|
RASHLEIGH, B., S. T. PURUCKER, L. M. PRIETO, L. A. SUAREZ, AND R. B. AMBROSE. The Response of Fish Habitat to Environmental Flows in the Albemarle-Pamlico Watershed. Presented at Southeastern Environmental Flows Partnership Conference, Athens, GA, October 27 - 29, 2008.
|
| Abstract:
|
The provision of habitat for fish is an important service provided by rivers. Future land development and climate change will likely alter several aspects of habitat, including flow. We have used hierarchical models to predict the presence of 25 fish species within the Albemarle-Pamlico basin, using predictors of land use, flow, temperature, and environmental setting from the USGS NHD Plus dataset. The most parsimonious models for these species typically included positive responses to either flow or velocity. These models are being linked within the FRAMES modeling framework where dynamic hydrologic and hydrodynamic models (SWAT and WASP) provide time-series inputs for the habitat models. This framework can serve as a tool for the assessment of flow alteration in the context of multiple stressors.
|
|
| PRESENTATION |
Environmental Flow Modeling Challenges for Rapidly Urbanizing Watersheds |
10/27/2008
|
|
|
|
MOHAMOUD, Y. M. AND S. R. KRAEMER. Environmental Flow Modeling Challenges for Rapidly Urbanizing Watersheds. Presented at Southeastern Environmental Flows Partnership Conference, Athens, GA, October 27 - 29, 2008.
|
| Abstract:
|
It is a challenge for land use planners and water resource managers to balance water needs that support urban growth and economic development of a growing population and yet maintain ecological flow needs. Urban growth and the associated water resources development in a watershed directly influence environmental flows as more water is diverted from rivers or retained behind dams for public water supplies. Converting forest land to urban areas increases the percent of impervious land surfaces in the form of rooftops, driveways, and parking lots. Increased impervious cover also causes serious hydrologic alterations (e.g., increased surface runoff, decreased infiltration and groundwater recharges) that affect the health of aquatic ecosystems. Determining environmental flows is challenging when watershed conditions are changing and when natural hydrologic regimes are altered by urbanization and the demand for municipal water supply is increasing. It is impractical to determine environmental flows as a percentage of historical stream flows when a watershed is experiencing rapid urbanization and associated demands for water. In such cases, a suitable approach is to allocate environmental flows within a watershed-wide water allocation program, which is implemented in an overall watershed planning and management strategy. A two-stage modeling approach is proposed. The first stage simulates the effect of alternative urban development and water resources development and management scenarios on water availability and water quality. The second stage allocates water to multiple users to ensure that environmental flows of sufficient quantity and quality are available to aquatic habitats and organisms.
|
|
| PRESENTATION |
Partitioning and Phase Behavior of Ethanol Fuel Blends |
05/05/2008
|
|
|
|
WEAVER, J. W., D. L. SPIDLE, S. L. BIRD, AND S. SKAGGS. Partitioning and Phase Behavior of Ethanol Fuel Blends. Presented at 2008 International Oil Spill Conference, Savannah, GA, May 05 - 08, 2008.
|
| Abstract:
|
Presentation at the 2008 International Oil Spill Conference in May 2008.
|
|
| PRESENTATION |
Relationship Between Watershed Land Use and Denitrification Enzyme Activity in Headwater Streams |
05/27/2008
|
|
|
|
BURKE, R. A., K. M. FRITZ, B. R. JOHNSON, S. FULTON, AND C. Barton. Relationship Between Watershed Land Use and Denitrification Enzyme Activity in Headwater Streams. Presented at Denitrification Research Coordination Network Workshop, Cambridge, MD, May 27 - 30, 2008.
|
| Abstract:
|
Headwater streams are the dominant land-water interface across much of the landscape. Denitrification is an important ecological service provided by headwater streams. Anthropogenic inputs of N to terrestrial ecosystems largely result from agricultural practices. Animal agriculture is the largest agricultural sector in the southeastern U.S. The South Fork Broad River (SFBR) watershed in Georgia covers approximately 600 km in an important poultry production area. Poultry wastes are disposed of by application to pastures. Appalachia accounts for over a third of US coal production. Mountaintop mining/valley fill (MTM/VF) is a common coal mining practice in Appalachia that physically devastates the areas in which it is employed. From 1992 to 2002, approximately1200 miles of small streams were impacted by MTM/VF in Appalachia. Due to high variability and methodological problems associated with measuring in situ denitrification rates, various measures of denitrification potential have been developed. The assay of denitrification enzyme activity (DEA) developed by Smith and Tiedje is a commonly used measure of denitrification potential. In the DEA assay, O is removed, C and nitrate are present in excess, and growth is inhibited by chloramphenicol so that only the enzymes originally present in the sample contribute to N gas production. Our observations of relatively high DEA in streams with low nitrate levels suggests that there is a reservoir of denitrification potential in many headwater streams that should be considered a valuable ecosystem service worthy of protection.
|
|
| PRESENTATION |
Impact of Mountaintop Mining/Valley Fill on the Stable Carbon Isotopic Composition and Concentration of Dissolved Organic Carbon and Dissolved Inorganic Carbon in Headwater Streams |
08/25/2008
|
|
|
|
BURKE, R. A., K. M. FRITZ, B. R. JOHNSON, S. FULTON, AND C. Barton. Impact of Mountaintop Mining/Valley Fill on the Stable Carbon Isotopic Composition and Concentration of Dissolved Organic Carbon and Dissolved Inorganic Carbon in Headwater Streams. Presented at 6th International Conference on Applications of Stable Isotope Techniques to Ecological Studies, Honolulu, HI, August 25 - 29, 2008.
|
| Abstract:
|
Headwater streams are the dominant land-water interface across much of the landscape and provide many important ecological services. Cycling and transport of various carbon fractions, which serve as important food sources for downstream aquatic ecosystems, are among the important functions of headwater streams. Dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) are two of the most ecologically important carbon fractions. Mountaintop mining/valley fill (MTM/VF) coal mining results in burial of headwater streams and causes sedimentation and elevated levels of various chemical constituents. We are using a wet chemical oxidation analyzer coupled to an isotope ratio mass spectrometer to measure the stable carbon isotopic composition and concentrations of DOC and DIC and other parameters in reference and MTM/VF impacted streams in eastern Kentucky and southern West Virginia. Our results suggest that DOC in MTM/VF impacted streams is a mixture of relatively 13C-rich organic carbon released by mining activities and organic carbon derived from intact parts of the watershed.
|
|
| PRESENTATION |
Estimation of Henry's Law Constant for a Diverse Set of Organic Compounds from Molecular Structure |
08/17/2008
|
|
|
|
HILAL, S. H., A. N. Saravanaraj, AND L. A. Carreira. Estimation of Henry's Law Constant for a Diverse Set of Organic Compounds from Molecular Structure. Presented at 236th ACS National Meeting & Exposition, Philadelphia, PA, August 17 - 21, 2008.
|
| Abstract:
|
The SPARC (SPARC Performs Automated Reasoning in Chemistry) vapor pressure and activity coefficient models were coupled to estimate Henry’s Law Constant (HLC) in water and in hexadecane for a wide range of non-polar and polar organic compounds without modification or additional parameterization of the vapor pressure or activity coefficient models. The vapor pressure model describes the solute-solute intermolecular interactions in the pure liquid phase while the activity coefficient model describes the solute-solvent and solvent-solvent intermolecular interactions upon placing solute, i, in solvent, j. These intermolecular interactions are factored into dispersion, induction, H-bonding and dipole-dipole components upon moving a solute molecule from the gas to the liquid phase. These models were tested and validated on the largest experimental HLC data set to date. 1353 organic solutes, spanning a wide range of functional groups, dipolarities, and hydrogen-bonding capabilities. The RMS deviation error for the SPARC-calculated versus the experimental log HLC for 1220 compounds in water and for 562 compounds in hexadecane were 0.456 and 0.192 (log (mole/L)/(mole/L)), respectively.
|
|
| PRESENTATION |
Modeled Watershed Runoff Associated With Variations in Precipitation Data With Implications for Contaminant Fluxes |
09/08/2008
|
|
|
|
GOLDEN, H. E., C. D. KNIGHTES, E. COOTER, AND R. L. DENNIS. Modeled Watershed Runoff Associated With Variations in Precipitation Data With Implications for Contaminant Fluxes. Presented at Third Interagency Conference on Research in the Watersheds, Estes Park, CO, September 08 - 11, 2008.
|
| Abstract:
|
Watershed-scale fate and transport models are important tools for estimating the sources, transformation, and transport of contaminants to surface water systems. Precipitation is one of the primary inputs to
watershed biogeochemical models, influencing changes in the water budget of the surface, shallow subsurface, and deep groundwater zones, and as a result the transport of contaminants to surface water
systems. Knowledge of precipitation across watersheds is notably imperfect, and most watershed fate and transport studies focus on observed data at a few sites within or near the watersheds. However, as
numerous new generations of simulated and radar detected datasets of precipitation become increasingly refined, available, and applied to watersheds for a more spatially resolved estimate of precipitation,
questions remain as to how these will affect modeled runoff generation in watersheds and thus contaminant fluxes. We utilize observed and simulated precipitation data across representative wet, dry, and normal years (2001-2003) in the southeastern USA to assess how variations in precipitation estimates affect daily and monthly modeled runoff. We apply daily observed and simulated precipitation as input parameters to a grid-based watershed mercury (Hg) model (GBMM v2.0, Tetra Tech, 2006) that computes daily mass balances for hydrology, sediment, and mercury within each GIS raster grid cell and produces flux estimates of each to a tributary network. Preliminary results suggest that although modeled precipitation resolves spatial issues associated with sparsely located precipitation gage data, observed precipitation data generates daily and monthly variations in runoff closer to observed runoff than modeled precipitation data. Results also illustrate that simulated precipitation data do not reflect rapid changes in daily rainfall
and subsequent runoff responses as well as observed precipitation data. The study highlights the importance of calculating uncertainties associated with precipitation and how these uncertainties are
reflected in modeled runoff generation, particularly as it is linked to watershed contaminant fluxes.
|
|
| PRESENTATION |
Site Information Management: Visualizing and Making Decisions |
06/03/2008
|
|
|
|
PURUCKER, S. T., J. Bing-Canar, R. Howe, AND C. Pachon. Site Information Management: Visualizing and Making Decisions. Presented at ConSoil 2008, 10th International Conference on Soil-Water Systems, Milan, ITALY, June 03 - 06, 2008.
|
| Abstract:
|
Presentation at Tenth International Conference on Soil-Water Systems, June 2008.
|
|
| PRESENTATION |
Method Development for the Determination of Fluorotelomer Alcohols in Soils By Gas Chromatography Mass Spectrometry |
06/03/2008
|
|
|
|
ELLINGTON, J. J., J. W. WASHINGTON, J. J. EVANS, T. JENKINS, AND S. Hafner. Method Development for the Determination of Fluorotelomer Alcohols in Soils By Gas Chromatography Mass Spectrometry. Presented at PFAA (Perfluorinated Alkyl Acids) Days II Workshop, Research Triangle Park, NC, June 03 - 05, 2008.
|
| Abstract:
|
Fluorotelomer alcohols (FTOHs) have been widely studied as precursors to perfluorocarboxylates, e.g. 8:2 FTOH degrades to perfluorooctanoic acid (PFOA). This presentation describes an analytical method for the extraction and analysis of 6:2, 8:2, and 10:2 FTOHs. Gas chromatograph/chemical ionization-mass spectrometry (GC/CI-MS) was used for sensitive determination of the fluortelomer alcohols. The best selectivity and sensitivity was observed when the detector was operated in the positive mode (GC/PCI-MS).
|
|
| PRESENTATION |
Incorporation of Modeling in Assessment of Diving Plumes |
06/04/2008
|
|
|
|
WEAVER, J. W. AND V. GOROKHOVSKI. Incorporation of Modeling in Assessment of Diving Plumes. Presented at Alabama Department of Environmental Management Groundwater Conference, Montgomery, AL, June 03 - 05, 2008.
|
| Abstract:
|
Powerpoint presentation on modeling in assessment of diving plumes.
|
|
| PRESENTATION |
Determination of Perfluorocarboxylic Acids in Sludge |
06/03/2008
|
|
|
|
Yoo, H., J. W. WASHINGTON, AND T. JENKINS. Determination of Perfluorocarboxylic Acids in Sludge. Presented at PFAA (Perfluorinated Alkyl Acids) Days II Workshop, Research Triangle Park, NC, June 03 - 05, 2008.
|
| Abstract:
|
Methods were developed for the extraction from wastewater-treatment sludge and quantitation by LC/MS/MS of perfluorocarboxylic acids (PFCAs, C6 to C12), 7-3 fluorotelomer carboxylic acid (7-3 FTCA) and 8-2 fluorotelomer 2-unsaturated carboxylic acid (8-2 FTUCA) using LC/MS/MS.
|
|
| PRESENTATION |
Ethanol and Lead Scavengers in U.S. Gasolines |
06/04/2008
|
|
|
|
WEAVER, J. W., D. L. SPIDLE, AND S. SKAGGS. Ethanol and Lead Scavengers in U.S. Gasolines. Presented at Alabama Department of Environmental Management Groundwater Conference, Montgomery, AL, June 03 - 05, 2008.
|
| Abstract:
|
Powerpoint presentation on ethanol and lead scavengers in gasoline.
|
|
| PRESENTATION |
Environmental Contaminants That Degrade in the Environment: Do They Really Disappear? |
06/03/2008
|
|
|
|
RICHARDSON, S. D. Environmental Contaminants That Degrade in the Environment: Do They Really Disappear? Presented at 56th ASMS Conference on Mass Spectrometry, Denver, CO, June 01 - 05, 2008.
|
| Abstract:
|
Slide presentation for the American Society for Mass Spectrometry 2008 meeting in Denver, CO.
|
|
| PRESENTATION |
Using Asymmetric Flow Field-Flow Fractionation (Af4) to Determine C60 Colloidal Size Distributions |
06/23/2008
|
|
|
|
ISAACSON, C., X. MA, AND D. BOUCHARD. Using Asymmetric Flow Field-Flow Fractionation (Af4) to Determine C60 Colloidal Size Distributions. Presented at Gordon Research Conference, Environmental Sciences: Water, Holderness, NH, June 22 - 27, 2008.
|
| Abstract:
|
The formation of aqueous fullerene suspensions by solvent exchange, sonication, or extended mixing in water is widely reported. Commonly used methods for determining the size of these aggregates rely on static and dynamic light scattering, electron microscopy (EM), or atomic force microscopy (AFM). Light scattering techniques are limited by poor resolution and sample heterogeneity, while EM and AFM techniques require extensive sample preparation which may alter aggregate size. Asymmetric flow field-flow fractionation (AF4) is a fractionation technique which is able to separate particles ranging from 1 nm to 10 µm based on particle diffusion coefficients. When combined with in-line with light scattering detectors, AF4 methods can be developed for the separation and size determinations of mono- or polydisperse samples. AF4 fractionation methods using NaCl, Tris and HEPES buffers, and the surfactants sodium dodecyl sulftate and FL-70 (a mixture of anionic and cationic surfactants) were developed to determine the size distribution of fullerene suspensions generated by a range of solvent exchange and extended stirring techniques.
|
|
| PRESENTATION |
Characterizing Fullerene Nanoparticles in Aqueous Suspensions |
09/23/2008
|
|
|
|
BOUCHARD, D., X. MA, AND C. ISAACSON. Characterizing Fullerene Nanoparticles in Aqueous Suspensions. Presented at American Chemical Society 42nd Western Regional Meeting , Las Vegas, NV, September 23 - 27, 2008.
|
| Abstract:
|
Studies have indicated that fullerenes can form stable colloidal suspensions in water when introduced to the aqueous phase through solvent exchange, sonication, or extended mixing. The colloidal suspensions created using these techniques have effective aqueous phase concentrations of fullerenes that are many orders of magnitude above their aqueous solubility. Analyzing these suspensions poses challenges in collecting representative suspension samples and in characterizing the fullerene nanomaterials in suspension with respect to particle size, surface potential, and mass. In this study, aqueous fullerene suspensions were formed at pH’s of 4, 7, and 10 in 10mM NaCl equivalent using the extended stirring technique, which does not employ organic solvents, as this technique is more representative of actual environmental conditions. Suspensions were also formed using ground and surface waters. The suspensions were then characterized for fullerene mass concentration, particle size, morphology, and surface potential (zeta potential). Fullerene mass concentration was determined by extracting the fullerenes from the aqueous phase using a liquid-liquid extraction procedure. Fullerenes in the extract were then separated and quantitated by HPLC-UV. Fullerene particle size analysis was achieved using dynamic light scattering, electrophoretic mobilities of fullerene aggregates were measured using laser Doppler velocimetry, and particle size and morphology were evaluated using atomic force microscopy (AFM) and transmission electron microscopy (TEM).
|
|
| PRESENTATION |
Recovery of a PCB-Contaminated Creek Fish Community |
11/16/2008
|
|
|
|
RASHLEIGH, B., M. C. BARBER, AND D. M. WALTERS. Recovery of a PCB-Contaminated Creek Fish Community. Presented at SETAC 29th Annual Meeting, Tampa, FL, November 16 - 20, 2008.
|
| Abstract:
|
Polychlorinated Biphenyls (PCBs) from the Sangamo-Weston Superfund Site near Clemson, South Carolina, USA, were released into the Twelvemile Creek until the early 1990s. PCB concentrations in fish in this creek have remained elevated: levels in six target fish species are still above the wildlife limits for kingfisher and mink. We used the AQUATOX model to represent the concentrations and dynamics of total PCB in a system of six connected creek segments. Studies in this system that classified gut contents of six fish species into eight food item categories were used to parameterize the food web. The model was calibrated to measured data then used to estimate recovery for the different species, sites, and system as a whole. The model can be used to predict future PCB concentrations in fish under different model assumptions (fish movement between segments, varying habitat conditions) and different management scenarios (proposed dam removal).
|
|
| PRESENTATION |
Formation and Occurrence of Disinfection By-Products |
10/20/2008
|
|
|
|
RICHARDSON, S. D. Formation and Occurrence of Disinfection By-Products. Presented at Environmental Mutagen Society Annual Meeting, Rio Grande, PUERTO RICO, October 18 - 22, 2008.
|
| Abstract:
|
Disinfection by-products (DBPs) are formed when disinfectants such as chlorine, ozone, chlorine dioxide, or chloramines react with naturally occurring organic matter, anthropogenic contaminants, bromide, and iodide during the production of drinking water. There is concern about DBPs due to bladder cancer and reproductive/developmental effects that have been associated with them in human epidemiologic studies. A recent review published in 2007 (Richardson et aI., Mutation Research 2007, 636, 178-242) provided an analysis of 30 years of published research on the occurrence, genotoxicity, and carcinogenicity of regulated and emerging DBPs, as well as a roadmap for future research. This presentation will focus on the formation and occurrence of these DBPs from different disinfectants. Emerging, unregulated DBPs discussed include halonitromethanes, iodo-acids and other unregulated halo-acids, iodo-trihalomethanes, halofuranones, haloamides, haloacetonitriles, and nitrosamines. Strategies for minimizing DBP formation will also be discussed.
|
|
| PRESENTATION |
Conazole Fungicides as Chiral Environmental Contaminants: Enantiomer Analysis and Enantioselectivity in Soil Slurries |
11/16/2008
|
|
|
|
GARRISON, A. W., J. K. AVANTS, AND W. J. JONES. Conazole Fungicides as Chiral Environmental Contaminants: Enantiomer Analysis and Enantioselectivity in Soil Slurries. Presented at SETAC 29th Annual Meeting, Tampa, FL, November 16 - 20, 2008.
|
| Abstract:
|
Conazoles are triazole compounds, many of which are in wide use as agricultural and medicinal fungicides. Opportunities exist for them to contaminate the environment and, since they are all chiral molecules, they are apt to be degraded enantioselectively by indigenous microbes. To characterize such enantioselectivity, it is necessary to analyze environmental samples for the separate conazole enantiomers. In most of the present study, enantiomer analysis was accomplished using a BGB-172 chiral GC column; detection was by GC-MS. For occasional confirmation, enantiomer analyses was performed by capillary electrophoresis (CE) in the micellar electrokinetic chromatography mode using various cyclodextrin chiral selectors. Research reported here involved the conazoles triadimefon, triadimenol, and propiconazole. Complete enantiomeric separation was achieved using either GC or CE for the enantiomers of all 3 fungicides.
|
|
| PRESENTATION |
How Are Changing Solar Ultraviolet Radiation and Climate Affecting Light-Induced Chemical Processes in Aquatic Environments? |
06/30/2008
|
|
|
|
ZEPP, R. G. How Are Changing Solar Ultraviolet Radiation and Climate Affecting Light-Induced Chemical Processes in Aquatic Environments? Presented at Northeast Regional Meeting of the American Chemical Society, Burlington, VT, June 29 - July 02, 2008.
|
| Abstract:
|
Changes in the ozone layer over the past three decades have resulted in increases in solar UV-B radiation (280-315 nm) that reach the surface of aquatic environments. These changes have been accompanied by unprecedented changes in temperature and precipitation patterns around the globe. Here the interactions of these environmental changes with light-induced chemistry are highlighted. The chromophoric (or colored) component of dissolved organic matter (DOM) in aquatic environments, often referred to as CDOM, strongly absorbs solar ultraviolet (UV) radiation and thus controls the penetration of biologically harmful solar UV into many freshwater and marine ecosystems. Climatic conditions can strongly influence CDOM concentrations and thus UV penetration. For example, long periods of dry, warm weather reduce CDOM inputs, thus permitting the removal processes to significantly reduce CDOM levels and enhance UV penetration. This effect can be amplified during the summer when stratification greatly slows inputs of CDOM into the upper layers of a water body from deeper waters. Photodegradation of CDOM results in loss of UV and visible absorbance, a process referred to as "photobleaching". Action spectra (plots of the ratio, molecules reacted: incident photons, versus wavelength) indicate that the UV-B component of sunlight is most effective at inducing CDOM photoreactions. In addition to spectral changes, photoreactions result in changes in the biological availability of CDOM carbon- and nitrogen-containing constituents and of metal-DOM complexes. For example, the organonitrogen components are photo degraded to produce ammonium. Photoreactions of organic complexes with metals (e.g. iron, copper) involve either direct photoreactions of the complexes or reactions of the complexes with reactive oxygen species that are produced photochemically. Methods that are being used to study these interesting reactions in the laboratory and field will be discussed as will approaches to modeling the effects of these photoreactions on aquatic biogeochemical cycles.
|
|
| PRESENTATION |
The Next Generation of Disinfection By-Products |
09/25/2008
|
|
|
|
RICHARDSON, S. D. The Next Generation of Disinfection By-Products. Presented at ISC 2008 - 27th International Symposium on Chromatography, Munster, GERMANY, September 21 - 25, 2008.
|
| Abstract:
|
The disinfection of drinking water has been rightly hailed as a public health triumph of the 20th century. Millions of people worldwide receive quality drinking water every day from their public water systems. However, chemical disinfection has also produced an unintended health hazard: the potential for cancer and reproductive/developmental effects that are associated with chemical disinfection by-products (DBPs). Chemical disinfectants are effective for killing harmful pathogens in drinking water, but they are also powerful oxidants, oxidizing the organic matter, anthropogenic contaminants, and bromide/iodide naturally present in most source waters (rivers, lakes, and many groundwaters). Chlorine, ozone, chlorine dioxide, and chloramines are the most common disinfectants in use today, and each produces its own suite of DBPs in drinking water. Out of more than 600 DBPs known, only 11 are currently regulated in the United States. And, those that are regulated do not cause the primary type of cancer (bladder cancer) that is observed in the human epidemiologic studies. Recent research has identified 'emerging', unregulated DBPs that are more cytotoxic and genotoxic than those that are currently regulated, and the use of newer alternative disinfectants (chloramines, ozone, chlorine dioxide) can increase their formation. This is important because many drinking water utilities in the U.S. are changing from chlorine to alternative disinfectants to meet stricter regulations. Emerging DBPs include iodo-acids, iodo-trihalomethanes (lodo-THMs), bromonitromethanes, haloamides, and nitrosamines (including nitrosodimethylamine, NDMA). New research on emerging DBPs will be presented, along with results from an occurrence study of iodo-acids and iodo-THMs and new research on high molecular weight DBPs. Finally, results from a new EPA study (the Four Lab Study), which involves the chemical and toxicological evaluation of complex drinking water mixtures treated with chlorine and alternative disinfectants, will be briefly discussed, along with other important new health effects information. Research in the discovery of new, emerging DBPs has included the use of gas chromatography (GC) with low and high resolution mass spectrometry (MS), as well as liquid chromatography (LC)/MS(/MS). Details on the use of these techniques will also be presented.
|
|
| PRESENTATION |
The Use of Aquatic Ecosystem Modeling in Environmental Management |
08/13/2008
|
|
|
|
RASHLEIGH, B., M. C. BARBER, AND D. M. WALTERS. The Use of Aquatic Ecosystem Modeling in Environmental Management. Presented at Environmental Leadership Program Webinar, Athens, GA, August 13, 2008.
|
| Abstract:
|
Presentation on the use of aquatic ecosystem modeling in environmental management.
|
|
| PRESENTATION |
Hepatotoxicity of Chlorpyrifos in Zebrafish Liver Cells By Nmr-Based Metabolomics |
09/02/2008
|
|
|
|
Huang, W., Q. TENG, D. R. EKMAN, AND T. W. COLLETTE. Hepatotoxicity of Chlorpyrifos in Zebrafish Liver Cells By Nmr-Based Metabolomics. Presented at Metabolomics Society's 4th Annual International Conference, Boston, MA, September 02 - 06, 2008.
|
| Abstract:
|
For decades chlorpyrifos (CPS) has been one of the most widely used organophosphate insecticides for a variety of agricultural and public health applications. The extensive use of CPS inevitably results in exposure to a small number of the human population. It is believed that the chemical is metabolically oxidized to its oxygen analog, chlorpyrifos oxon (CPO), which can cause acute toxicity in humans by the inhibition of acetylcholinesterase in the central nervous systems. The metabolical oxidization of CPS to CPO primarily occurs in livers by multiple cytochrome P450 (CYP) enzyme isoforms. The aim of this study is to identify the metabolic changes in zebrafish (Danio rerio) liver cells (ZFL) caused by CPS and CPO at different dose levels and to investigate any differences in the cells response to the exposure of the two chemicals. This study is also a proof-of-concept for in-vitro metabolomics using fish cell culture as a model for testing chemical toxicity.
|
|
| PRESENTATION |
Metabolic Changes Caused By Ethinylestradiol in Human Breast Cancer Cells as Observed By Nmr Spectroscopy |
09/02/2008
|
|
|
|
TENG, Q., W. Huang, D. R. EKMAN, AND T. W. COLLETTE. Metabolic Changes Caused By Ethinylestradiol in Human Breast Cancer Cells as Observed By Nmr Spectroscopy. Presented at Metabolomics Society's 4th Annual International Conference, Boston, MA, September 02 - 06, 2008.
|
| Abstract:
|
To conduct cell culture based metabolomics, we have developed a novel sample preparation method using adherent mammalian cells, which is rapid, effective, and exhibits greater metabolite retention by approximately a factor of 50 compared to the conventional sample preparation method. We have applied this approach to study the metabolic changes caused by 17alpha-ethynylestradiol (EE2) in estrogen receptor (ER)-positive MCF-7 and ER-negative MDA-MB-231 human breast cancer cell lines using NMR spectroscopy. Details of sample preparation, NMR spectroscopy, metabolite identification, statistical analysis and intracellular metabolic changes will be presented.
|
|
| PRESENTATION |
Toxicity Assessment of 17 Alpha-Ethinylestradiol By Cell-Culture Based Nmr Metabolomics |
09/02/2008
|
|
|
|
EKMAN, D. R., Q. TENG, W. Huang, AND T. W. COLLETTE. Toxicity Assessment of 17 Alpha-Ethinylestradiol By Cell-Culture Based Nmr Metabolomics. Presented at Metabolomics Society's 4th Annual International Conference, Boston, MA, September 02 - 06, 2008.
|
| Abstract:
|
A zebrafish liver cell line (ZFL) established from adult zebrafish has been used in a variety of biological research, including toxicology, pharmacology, developmental biology and molecular genetics. The goal of this study is to develop an in vitro approach to identify the responsive changes in cellular metabolic profiles induced by the exposure of chemicals. The metabolites of the cellular extracts were profiled by 1D NOESY NMR experiments. Statistical analysis showed that the perturbational metabolic profiles in the ZFL cells exposed to EE2 have both dose- and time-dependences. The results demonstrated that cell culture based metabolomics using zebrafish liver cell line can potentially be used to screen chemicals for ecotoxicity. We are currently applying the in vitro metabolomics approach to assess toxicity of chemicals in human cell lines. Details of sample preparation, NMR spectroscopy, metabolite identification, statistical analysis and cellular metabolite profiling will be presented.
|
|
| PRESENTATION |
Light-Induced Decomposition of Surface Litter from the Cerrado in Central Brazil |
11/17/2008
|
|
|
|
ZEPP, R. G., M. MOLINA, M. J. CYTERSKI, K. Kisselle, A. R. Kozovits, M. R. Silva, D. A. da Silva, AND M. M. Bustamante. Light-Induced Decomposition of Surface Litter from the Cerrado in Central Brazil. Presented at Amazon in Perspective: International Science Conference, Manaus, BRAZIL, November 17 - 20, 2008.
|
| Abstract:
|
It is well-established that light-induced decomposition can accelerate the decomposition of the organic matter in aquatic environments. In this study, using the production of carbon monoxide as an indicator of decomposition, we investigated the wavelength dependence of the photodegradation of the litter derived from several plant species of the Cerrado. Using polychromatic UV and visible radiation with a series of cutoff filters, as originally described by Rundel (Physiol. Plant. 1986, 58, 360-366), we determined action spectra for the photodegradation. The action spectra indicated that the UV component of sunlight is primarily responsible for litter photodegradation. We also used the action spectra to model relationships between litter photodegradation rates and measurements of solar irradiance such as PAR or total irradiance that are commonly used to model terrestrial carbon dynamics based on satellite data. In addition to the litter photodecomposition studies, we conducted laboratory incubation studies on the effects of added fertilizers on bacterial consumption of carbon monoxide in soil samples obtained from native Cerrado areas (20-50% canopy cover). The studies were conducted in gas-tight jars maintaining the same soil moisture level throughout treatments. CO was taken up by the soil cores in all cases and the uptake was quantified as deposition velocities.
|
|
| PRESENTATION |
Investigating Adaptive, Compensatory, and Toxic Responses of Fathead Minnow (pimephales Promelas) Exposed to 17α-Ethynylestradiol Using Nmr-Based Metabolite Profiling |
10/05/2008
|
|
|
|
EKMAN, D. R., T. W. COLLETTE, Q. TENG, G. T. ANKLEY, E. J. DURHAN, K. M. JENSEN, M. D. KAHL, D. MARTINOVIC, AND D. L. VILLENEUVE. Investigating Adaptive, Compensatory, and Toxic Responses of Fathead Minnow (pimephales Promelas) Exposed to 17α-Ethynylestradiol Using Nmr-Based Metabolite Profiling. Presented at 35th Annual Aquatic Toxicity Workshop, Saskatoon, SK, CANADA, October 05 - 08, 2008.
|
| Abstract:
|
Determining the impact(s) on fish and other aquatic organisms of exposure to endocrine disrupting compounds (EDCs) is critical for determining the risks that these chemicals pose. However, to accurately evaluate these risks, beyond simply measuring a “before and after exposure” snapshot, researchers must assess the ability of the exposed organisms to adapt to, or compensate for the presence of these compounds. The extent of true harm from sub-lethal exposure is often a complex relationship of both time and chemical concentration. Due to the large number of samples required to map this complex response profile, a robust molecular technique with low per-sample cost of analysis is desirable. In response to this need, we have employed a metabolomics approach for studying these responses in small-fish toxicity models (e.g., fathead minnow) using nuclear magnetic resonance (NMR) spectroscopy. This approach provides the ability to measure molecular responses in different tissue and biofluid types, both rapidly and inexpensively, making it ideal for this application. Using this approach, we have been able to observe apparent compensatory responses to the presence of EDCs over the duration of an exposure. Furthermore, it appears that after the chemical has been removed from the water (i.e. during a depuration phase) that fish are able in some cases to return to a near “pre-exposure” state, providing evidence of partial recovery. These results demonstrate the potential of this approach for improving the assessment of risk(s) that various EDCs pose to sentinel small-fish species.
|
|
| PRESENTATION |
Ecosystem Services Modeling Infrastructures: Simile/Mimes (Gund Institute) and Frames/3mra (US EPA) Integrated Modeling for Forecasting |
10/17/2008
|
|
|
|
JOHNSTON, J. M., G. F. LANIAK, R. R. Lassiter, R. Boumans, D. Ames, AND K. Reckhow. Ecosystem Services Modeling Infrastructures: Simile/Mimes (Gund Institute) and Frames/3mra (US EPA) Integrated Modeling for Forecasting. Presented at Ecosystem Services Conference, Beijing, CHINA, October 13 - 17, 2008.
|
| Abstract:
|
The Ecological Research Program (ERP) of the EPA Office of Research and Development has the vision of a comprehensive theory and practice for characterizing, quantifying, and valuing ecosystem services and their relationship to human well-being for environmental decision making. This vision of future environmental decision-making is planned as an innovative, online decision support platform with a full range of data exploration methods, models and decision options, and is intended to be a dynamic connection between managers and policy developers and their ecosystems and bundled services of interest, from local to regional and national scales. Forecasting of alternative future ecosystem states driven by land use change, climate change and multiple stressors, and in response to alternative decisions, is foreseen as leading to better long-term decisions. Two mature modeling frameworks and their associated science being evaluated for the requirements of the ecology program are Simile/MIMES and FRAMES/3MRA.
|
|
| PRESENTATION |
Modeling Watershed Mercury Response to Atmospheric Loadings: Response Time and Challenges |
12/15/2008
|
|
|
|
GOLDEN, H. E. AND C. D. KNIGHTES. Modeling Watershed Mercury Response to Atmospheric Loadings: Response Time and Challenges. Presented at American Geophysical Union Fall Meeting, San Francisco, CA, December 15 - 19, 2008.
|
| Abstract:
|
The relationship between sources of mercury to watersheds and its fate in surface waters is invariably complex. Large scale monitoring studies, such as the METAALICUS project, have advanced current understanding of the links between atmospheric deposition of mercury and accumulation of methyl mercury in fish tissue. However, effective watershed-scale models simulating the effects of changes in mercury deposition on surface soil mercury concentrations and watershed mercury loadings are currently lacking. As a result, numerous default assumptions - such as steady state relationships between atmospheric loading of total mercury and methyl mercury concentrations in surface waters - are required for management purposes (e.g, total maximum daily loads (TMDLs)). We use a spatially distributed watershed fate and transport model to simulate historic and future patterns of watershed soil mercury concentrations and associated watershed loadings in two watersheds within the Cape Fear River Basin, North Carolina. Simulations were initiated using background soil concentrations and constant atmospheric mercury deposition rates. We also simulate watershed mercury response (soil concentrations and loadings) during a period of locally-increased emissions from a mercury cell chlor-alkali facility (in operation from 1963-1999 using the mercury cell chlorine production process) and estimate the length of time for watershed mercury loading to return to baseline conditions after plant closure. All model simulations are performed using a recently developed spatially distributed grid-based watershed mercury (Hg) model (GBMM v2.0, Tetra Tech, 2006) that computes daily mass balances for hydrology, sediment, and mercury within each GIS grid cell and produces daily flux estimates of each to a tributary network. We present preliminary results suggesting that after more than 150 years, watershed response to atmospheric loading does not reach a steady-state condition, which is potentially attributed to lack of extreme overland runoff events during the simulation period and increased storage due to low soil mercury reduction rates. We discuss the implications of this for managing mercury in aquatic ecosystems. Further, we explore the time lag between decreasing emissions near the chlor-alkali facility and return of soil mercury concentrations and watershed mercury loadings to baseline conditions.
|
|
| PRESENTATION |
Numerical Modeling of One-Dimensional Steady-State Flow and Contaminant Transport in a Horizontally Heterogeneous Unconfined Aquifer With An Uneven Base |
12/15/2008
|
|
|
|
Gorokhovski, V. M. AND J. W. WEAVER. Numerical Modeling of One-Dimensional Steady-State Flow and Contaminant Transport in a Horizontally Heterogeneous Unconfined Aquifer With An Uneven Base. Presented at American Geophysical Union Fall Meeting, San Francisco, CA, December 15 - 19, 2008.
|
| Abstract:
|
Algorithms and a short description of the D1_Flow program for numerical modeling of one-dimensional steady-state flow in horizontally heterogeneous aquifers with uneven sloping bases are presented. The algorithms are based on the Dupuit-Forchheimer approximations. The program permits evaluation of water table elevations, tracking streamlines, delineating bounds of contaminant plume, and estimating advective travel times. The D1_Flow program was tested against three types of analytical solutions, data from the Borden Landfill, and results obtained by the two-dimensional model used on the landfill previously. The program yielded results practically coinciding with each of these. With its flexible boundary conditions and rapid execution, the code can form a suitable basis for a plume diving calculation and be integrated into a site assessment.
|
|
| PRESENTATION |
Semi-Analytical Models of Co2 Injection Into Deep Saline Aquifers: Evaluation of the Area of Review and Leakage Through Abandoned Wells |
12/15/2008
|
|
|
|
KRAEMER, S. R., D. C. DIGIULIO, AND A. LEVINE. Semi-Analytical Models of Co2 Injection Into Deep Saline Aquifers: Evaluation of the Area of Review and Leakage Through Abandoned Wells. Presented at 2008 AGU Fall Meeting, San Francisco, CA, December 15 - 19, 2008.
|
| Abstract:
|
This presentation will provide a conceptual preview of an Area of Review (AoR) tool being developed by EPA’s Office of Research and Development that applies analytic and semi-analytical mathematical solutions to elucidate potential risks associated with geologic sequestration of carbon dioxide into deep saline subsurface formations. These solutions can be applied to commercial scale injections of supercritical CO2 and enable the zone of influence and potential endangerment to be mapped, thereby helping to delineate the AoR. We anticipate implementing the semi-analytical solutions into an open source computer modeling framework. The major risks to be evaluated by the AoR tool include: induced subsurface pressures that may force native saline waters into an underground source of drinking water (USDW), and the potential transport of CO2 away from the injection center and out of the receiving zone. Both of these phenomena are influenced by leakage and compromises of the sealing layers, such as presented by abandoned wells or other subsurface penetrations. The semi-analytical solutions will be tested against numerical solutions (TOUGH2/ECO2N) and field data associated with the Kimberlina test injection site near Bakersfield, CA. The AoR tool will be used to simulate a hypothetical commercial scale injection and to evaluate if existing or potential USDW aquifers may be adversely impacted by short-term or long-term geologic sequestration activities. The AoR tool will be useful for permit applicants and regulators evaluating potential exposure and risks associated with geoequestration under the Underground Injection Control (UIC) program.
|
|
| PRESENTATION |
Emerging Contaminants in Water: A Perspective from the United States |
09/22/2008
|
|
|
|
RICHARDSON, S. D. Emerging Contaminants in Water: A Perspective from the United States. Presented at Workshop on the Water Framework Implementation on Priority and Emerging Pollutants, Koblenz, GERMANY, September 22 - 24, 2008.
|
| Abstract:
|
Workshop presentation on emerging contaminants in water.
|
|
| PRESENTATION |
Formation of Emerging and High Molecular Weight DBPs from Nom |
09/29/2008
|
|
|
|
RICHARDSON, S. D. Formation of Emerging and High Molecular Weight DBPs from Nom. Presented at Workshop on Natural Organic Matter in Natural and Technical Processes, Lake Constance, GERMANY, September 29 - October 01, 2008.
|
| Abstract:
|
Workshop presentation on formation of emerging disinfection by-products reacting with natural organic matter.
|
|
| PRESENTATION |
Tools for Assessing Ecological Nanomaterial Exposures |
10/04/2008
|
|
|
|
LOUX, N. T., B. VERONESI, Y. Su, AND S. A. DIAMOND. Tools for Assessing Ecological Nanomaterial Exposures. Presented at Conference on Aquatic Conservation Science: Merging Theory and Application, Athens, GA, October 03 - 04, 2008.
|
| Abstract:
|
Manufactured nanomaterials (MNs) are commonly defined as being
commercial products with at least one dimension in the size range of 1
nm to 100 nm that also possess unique properties as the result of
their size. Anecdotal evidence suggests that at least 600 MN products
are currently in commercial production and that the number of products
in commerce is expected to increase in an exponential fashion. Several national/international organizations with regulatory authority are in the process of assessing whether the existing physical/chemical/toxicological test guidelines that are applied to
commercial chemicals are adequate for assessing the environmental risks posed by MNs when intentionally or unintentionally introduced into the environment. In addition, possible new test guidelines are under
examination in order to address the unique properties of these products.
The environmental dispersal of MNs has the potential to adversely impact such ecosystem services as clean water, food provisioning and recreation. However, due to their unique properties, it is not clear whether existing environmental fate, transport, exposure and persistence models can be expected to provide useful estimates of future biological exposures to these products. This presentation will describe progress made in adapting existing fate,transport and exposure models to this new class of commercial products.
|
|
| PRESENTATION |
Analysis of Fish and Shellfish Community Patterns in the Mobile Bay Estuary, USA |
10/20/2008
|
|
|
|
RASHLEIGH, B., M. J. CYTERSKI, L. M. SMITH, AND J. NESTLERODE. Analysis of Fish and Shellfish Community Patterns in the Mobile Bay Estuary, USA. Presented at NATO CCMS Final Workshop on Experiences and Challenges on Sustainable Use and Development of Coastal Lagoons, Dalaman, TURKEY, October 20 - 24, 2008.
|
| Abstract:
|
To present information on the analysis of fish and shellfish community patterns in the Mobile Bay.
|
|
| PRESENTATION |
Meeting in Korea: Wasp Transport Modeling and Wasp Ecological Modeling |
11/03/2008
|
|
|
|
AMBROSE, R. B. AND T. A. WOOL. Meeting in Korea: Wasp Transport Modeling and Wasp Ecological Modeling. Presented at Training Course on WASP and EFDC Water Quality Modeling, Daejeon, SOUTH KOREA, November 01 - 08, 2008.
|
| Abstract:
|
A combination of lectures, demonstrations, and hands-on excercises will be used to introduce pollutant transport modeling with the U.S. EPA's general water quality model, WASP (Water Quality Analysis Simulation Program). WASP features include a user-friendly Windows-based interface, a data pre-processor, a selection of water quality modules, and a graphical post-processor.
|
|
| PRESENTATION |
Using a Metabolic Null Model to Predict Freshwater Fish Abundances at Regional to National Scales |
10/03/2008
|
|
|
|
MCGARVEY, D. J. Using a Metabolic Null Model to Predict Freshwater Fish Abundances at Regional to National Scales. Presented at Conference on Aquatic Conservation Science: Merging Theory and Application, Athens, GA, October 03 - 04, 2008.
|
| Abstract:
|
Poster presented at the Conference on Aquatic Conservation Science held in Athens, GA, October 3-4, 2008.
|
|
| PRESENTATION |
Interactions of Changing Solar Ultraviolet Radiation and Climate With Light Induced Chemical Reactions in Aquatic Environments |
10/10/2008
|
|
|
|
ZEPP, R. G. Interactions of Changing Solar Ultraviolet Radiation and Climate With Light Induced Chemical Reactions in Aquatic Environments. Presented at Michigan State University, Department of Chemistry, East Lansing, MI, October 10, 2008.
|
| Abstract:
|
Changes in the ozone layer over the past two decades have resulted in increases in solar ultraviolet radiation that reach the surface of North American aquatic environments. Concurrent changes in atmospheric CO2 are resulting in changes in stratification and precipitation that are affecting the chemical composition and light-induced processes of freshwaters and coastal marine environments. Recent research has provided evidence that interactions of solar UV radiation and the chromophoric component of dissolved organic matter, often referred to as CDOM, may play an important role in the functioning of aquatic ecosystems. CDOM strongly absorbs UV radiation and thus controls the penetration of biologically-harmful solar ultraviolet radiation into many freshwater and marine ecosystems. On irradiation, CDOM and its complexes with metals such as iron produce excited state and reactive oxygen species that mediate photosensitized reactions in aquatic environments. Photodegradation of CDOM results in loss of its UV and visible absorbance and fluorescence, a process referred to as photobleaching, changes in the biological availability of its carbon- and nitrogen-containing constituents, and production of carbon dioxide, carbon monoxide, volatile hydrocarbons, and sulfur-containing gases. This presentation will discuss kinetic and mechanistic approaches that are used to study these intriguing photoreactions in the laboratory and field.
|
|
| PRESENTATION |
U.S. EPA's Ecosystem Services Research for Coastal Wetlands |
10/20/2008
|
|
|
|
RASHLEIGH, B. U.S. EPA's Ecosystem Services Research for Coastal Wetlands. Presented at NATO CCMS Final Workshop on Experiences and Challenges on Sustainable Use and Development of Coastal Lagoons, Dalaman, TURKEY, October 20 - 24, 2008.
|
| Abstract:
|
Slide presentation on the EPA's ecosystem services research for coastal wetlands, NATO CCMS meeting in Dalaman, Turkey, October 2008.
|
|
| PRESENTATION |
Development of Water Quality Modeling in the United States |
11/06/2008
|
|
|
|
AMBROSE, R. B. Development of Water Quality Modeling in the United States. Presented at National Conference of the Korean Society of Environmental Engineering, Seoul, SOUTH KOREA, November 06, 2008.
|
| Abstract:
|
This presentation describes historical trends in water quality model development in the United States, reviews current efforts, and projects promising future directions. Water quality modeling has a relatively long history in the United States. While its origins lie in the work of Streeter and Phelps in the 1920’s, the practice began its first modern development phase with the availability of mainframe computers in the 1960s. Successive development phases have been driven by the availability of desktop computers in the late 1980s, improved Windows operating systems in the mid to late 1990s, and the internet in the later 1990s to the present. Model development has also been driven by the needs of regulation. The primary regulatory driver for water quality modeling in the U.S. has been the 1956 Federal Water Pollution Control Act, including the Clean Water Act and amendments of 1972, 1977, 1981, and 1987. Four US laws address the environmental risks from toxic substances and their effect on watersheds. These regulate industrial chemicals (Toxic Substances Control Act), contaminated sites (Superfund), hazardous waste (Resource Conservation and Recovery Act), and pesticides (Federal Insecticide, Fungicide, and Rodenticide Act). Most of the conventional water quality variables and processes were coded in modeling frameworks by the late 1970s, and toxicant variables and processes were coded by the mid-1980s. Since then, water quality modeling content has been slowly refined and improved in a variety of applications. Present high-end water quality models feature multiple algal groups and detrital variables, and linkages to sediment diagenesis modules. Faster computers have promoted dynamic, spatially-detailed simulations driven by better transport models. Specialized user interface software has promoted better water quality modeling practice. GIS software and on-line databases are promoting more realistic model parameterization and application. Robust frameworks are facilitating model linkage with databases and other models, which promises more comprehensive analyses of environmental problems. These trends and developments in water quality modeling in the United States will be described, and examples will be reviewed.
|
|
| PUBLISHED REPORT |
Fate of High Priority Pesticides During Drinking Water Treatment |
09/01/2008
|
|
|
|
DUIRK, S. E., L. M. Desetto, AND G. M. Davis. Fate of High Priority Pesticides During Drinking Water Treatment. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-08/089, 2008.
|
| Abstract:
|
The fate of organophosphorus (OP) pesticides in the presence of chlorinated oxidants was investigated under drinking water treatment conditions. In the presence of aqueous chlorine, intrinsic rate coefficients were found for the reaction of hypochlorous acid and hypochlorite ion with eight OP pesticides.
|
|
|
|
