
	Exposure Research

NERL News

About NERL

Where You Live

Publications/
Presentations

Assistance
Opportunities

Ecosystems Research Division Publications: 2007

This page lists publication titles, citations and abstracts produced by NERL's Ecosystems Research Division for the year 2007, organized by Publication Type. Your search has returned 169 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	Case Study: Dieldrin Attack in Dalyan Lagoon	04/03/2007

ERTURK, A., R. B. AMBROSE, AND B. RASHLEIGH. Case Study: Dieldrin Attack in Dalyan Lagoon. Chapter 17, I.E. Gonenc, V. Koutitonsky, B. Rashleigh, J.P. Wolflin and R.B. Ambrose, Jr. (ed.), Assessment of the Fate and Effects of Toxic Agents on Water Resources. Springer Netherlands, , Netherlands, 329-386, (2007).
Abstract:	During the first two weeks of December 2005, NATO sponsored an Advanced Study Institute (ASI) in Istanbul, Turkey. Part of this ASI involved a case study of a terrorist attack, where a chemical was assumed to be dumped into Sulunger Lake in Turkey. This chapter documents the response developed by the ASI participants to this scenario, in terms of hydrodynamic transport, ecosystem effects, and decision making.

BOOK CHAPTER	Assessment of Lake Ecosystem Response to Toxic Events With the Aquatox Model	04/03/2007

RASHLEIGH, B. Assessment of Lake Ecosystem Response to Toxic Events With the Aquatox Model. , Chapter 14, I.E. Gonenc, V. Koutitonsky, B. Rashleigh, J.P. Wolflin, and R.B. Ambrose, Jr. (ed.), Assessment of the Fate and Effects of Toxic Agents on Water Resources. Springer Netherlands, , Netherlands, 291-297, (2007).
Abstract:	An attack involving a toxic chemical added to a water resource could have multiple effects on the aquatic ecosystem of that resource. This is particularly significant for systems such as lakes and reservoirs, where the residence time of water is long and there is more opportunity for organisms to be exposed to the chemical. A toxic chemical release in a lake ecosystem may cause bioaccumulation in fish tissues for a period of time after an attack. Ecosystem dynamics in lakes and reservoirs are quite complex due to interactions and feedbacks between habitat, feeding relationships, and other physiological processes. Because of the complexities of lake and reservoir ecosystems, these systems are often represented and studied with simulation models. Here we use AQUATOX to model the effects of a toxic event on a lake ecosystem. Model applications such as this can be useful in contingency planning to assess ecosystem response to chemical releases under emergency conditions.

EPA PUBLISHED PROCEEDINGS	Symposium in Italy: Fish Physiology, Toxicology, and Water Quality	02/05/2007

U.S. EPA. Symposium in Italy: Fish Physiology, Toxicology, and Water Quality. Proceedings of the Ninth International Symposium, Capri, ITALY, April 24 - 28, 2006. C.J. Brauner, K. Suvajdzic, G. Nilsson, and D.J.Randall (ed.), U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-07/010, 2007.
Abstract:	Scientists from Europe, North America and South America convened in Capri, Italy, April 24-28, 2006 for the Ninth International Symposium on Fish Physiology, Toxicology, and Water Quality. The subject of the meeting was Eutrophication: The toxic effects of ammonia, nitrite and the detrimental effects of hypoxia on fish. These proceedings include 22 papers presented over a 3-day period and discuss eutrophication, ammonia and nitrite toxicity and the effects of hypoxia on fish with the aim of understanding the effects of eutrophication on fish. The ever increasing human population and the animals raised for human consumption discharge their sewage into rivers and coastal waters worldwide. This is resulting in eutrophication of rivers and coastal waters everywhere. Eutrophication is associated with elevated ammonia and nitrite levels, both of which are toxic, and the water often becomes hypoxic. Aquatic hypoxia has been shown to reduce species diversity and reduce total biomass.

JOURNAL	Enantiomeric Composition of Chiral Polychlorinated Biphenyl Atropisomers in Dated Sediment Cores	02/15/2007

WONG, C. S., U. PAKDEESUSUK, J. A. MORRISSEY, C. M. LEE, J. T. COATES, A. W. GARRISON, S. A. MABURY, C. H. MARVIN, AND D. C. MUIR. Enantiomeric Composition of Chiral Polychlorinated Biphenyl Atropisomers in Dated Sediment Cores. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 26(2):254-263, (2007).
Abstract:	Enantiomer fractions (EFs) of seven chiral polychlorinated biphenyl (PCB) congeners were measured in dated sediment cores of Lake Hartwell, SC, and Lake Ontario, to detect and quantify microbial reductive dechlorination of PCBs at high and low concentrations, respectively. Lake Hartwell sediments had high total PCB concentrations (5 to 60 micrograms/g), with accumulation and congener patterns consistent with PCB use there. Lake Hartwell sediment EFs were significantly nonracemic, and generally consistent with those from previous laboratory microcosm reductive dechlorination experiments with sediments taken from these sites. These results imply that sediment reductive dechlorination had occurred in situ, including at total PCB concentrations below the 30-80 micrograms/g threshold suggested as necessary for reductive dechlorination. Enantiomer fractions of PCBs 91, 95, 132 and 136 in Lake Hartwell cores were significantly correlated with both concentrations of those individual congeners as well as with total PCB concentration for some sites but not for others. This result suggests that stereoselective microbial dechlorination activity increased with higher concentrations and greater time within sediments, but also that these factors were not the only ones affecting stereoselective dechlorination activity. Comparison of EFs with dates suggest biotransformation half-lives of approximately 30 years, on the same time scale as burial sequestration. Enantiomer composition reversed with depth for PCBs 91, 132, and 176, suggesting there may be multiple microbial populations present within the same core enantioselectively dechlorinating PCBs. In contrast, Lake Ontario sediments (maximum total PCBs 400 nanograms/g) had racemic or near racemic amounts of most congeners throughout the core profile. This result is consistent with achiral indicators suggesting no microbial biotransformation within Lake Ontario sediments, and suggests that thresholds for reductive dechlorination may exist, but at concentrations below 30-80 micrograms/g.

JOURNAL	Drowning in Disinfection By-Products? Assessing Swimming Pool Water	01/15/2007

ZWIENER, C., S. D. RICHARDSON, D. M. DEMARINI, T. GRUMMT, T. GLAUNER, AND F. H. FRIMMEL. Drowning in Disinfection By-Products? Assessing Swimming Pool Water. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 41(2):363-372, (2007).
Abstract:	The development of treated water for swimming pools has made swimming a year round activity, widely enjoyed for leisure as well as exercise. Swimming pools can be found in different kinds and sizes in public areas, hotels and spas, or at private homes. In Germany ~250-300 million people visit pools each year, averaging 3 visits per capita. In the UK, one third of the children and ~36% of adults (>15 years of age) visit swimming pools at least once a week; 55% of children (5-9 years of age) use pools at least once a month. The highest numbers of existing in-ground and above-ground pools in Europe are found in France (773,000) and Germany (625,000), followed by the UK with 155,000 and Italy with 94,000. In the U.S., the current number of existing in-ground pools is estimated at 4,210,000 units (1). Pool water and other recreational waters are increasingly regarded as a health priority around the world. The World Health Organization (2) has identified some of the hazards associated with recreational water use, which include infections caused by feces-associated microbes, such as viruses and bacteria, as well as protozoa such as Giardia and Cryptosporidium, which are resistant to chlorine and other pool disinfectants. In the U.S., the National Swimming Pool Foundation (NSPF) has recently awarded the Centers for Disease Control and Prevention a grant to explore such health issues (3). "There is a compelling need to get some answers on the spread of recreational water illnesses," says NSPF's Chief Executive Officer, Thomas M. Lachocki (4). In the UK, technological developments, pool water quality, and governing standards were the topics of an International Conference held in 2002 in Cranfield (5). Beyond the engineering aspects of the pool itself, sufficient disinfection with a minimum of disinfection by-products (DBPs) is the other major issue in pool water treatment. The goal is to prevent illnesses associated with recreational water use (3) and to minimize any health impacts from excessive DBPs. Swimming pool water is a dynamic environment that changes with the climate, the number of people in the pool, activities of the swimmers, as well as environmental contaminants brought into the pool on the skin and clothes (bather load). Pool water must achieve suitable disinfection given this range of contamination while also accommodating a wide range of people: young children, pregnant women, the elderly, people with compromised immune systems, Olympic athletes, etc. This is a challenging environment in which to achieve a suitable public health outcome. The topic of optimized disinfection and minimized DBP formation by new treatment techniques was the focus of a recent collaborative research project in Germany titled "Pool Water Chemistry and Health," which was funded by the German Ministry of Education and Research (Bundesministerium fur Bildung and Forschung BMBF) and attended by experts from academia, industry, and the German Federal Environmental Agency (Umweltbundesamt). Researchers evaluated pool water quality from the perspectives of chemistry, technology, and health. The goals of the project were to explore aspects of pool water quality in terms of hygienic and chemical safety. Investigations were conducted in the fields of DBP formation, epidemiologic and toxicologic assessment of DBPs, and minimization of DBPs by new treatment technologies. Results were presented at an International Symposium on "Pool Water Chemistry and Health" in Karlsruhe, Germany in September 2003 (6). It became obvious that despite a fundamental knowledge of pool water quality and a well-developed tradition in pool water treatment, further research would help to characterize the health effects of swimming pool water.

JOURNAL	The Role of Nitrogen in Chromophoric and Fluorescent Dissolved Organic Matter Formation	01/08/2007

BIERS, E. J., R. G. ZEPP, AND M. A. MORAN. The Role of Nitrogen in Chromophoric and Fluorescent Dissolved Organic Matter Formation. MARINE CHEMISTRY. Elsevier Science Ltd, New York, NY, 103(1-2):46-60, (2007).
Abstract:	Microbial and photochemical processes affect chromophoric dissolved organic matter (CDOM) dynamics in the ocean. Some evidence suggests that dissolved nitrogen plays a role in CDOM formation, although this has received little systematic attention in marine ecosystems. Coastal seawater incubations were carried out in the presence of model dissolved organic nitrogen (DON: amino sugars and amino acids) and dissolved inorganic nitrogen (DIN) compounds to assess their role in biological and photochemical production of CDOM. For several of the dissolved N compounds, microbial processing resulted in a pulse of CDOM that was mainly labile, appearing and disappearing within 7 days. In contrast, a net loss of CDOM occurred when no N was added to the microbial incubations. The greatest net biological CDOM formation was found upon addition of amino sugars (formation of fluorescent, mostly labile CDOM) and tryptophan (formation of non-fluorescent, refractory CDOM). Photochemical formation of CDOM was only found with tryptophan, the one aromatic compound tested. This CDOM was highly fluorescent, with excitation-emission matrices (EEMs) resembling those of terrestrial, humic-like fluorophores. The heterogeneity in CDOM formation from this collection of labile N-containing compounds was surprising. These compounds are common components of biopolymers and humic substances in natural waters and likely to contribute to microbially- and photochemically-produced CDOM in coastal seawater.

JOURNAL	Conditions for Coexistence of Freshwater Mussel Species Via Partitioning of Fish Host Resources	02/24/2007

RASHLEIGH, B. AND D. L. DEANGELIS. Conditions for Coexistence of Freshwater Mussel Species Via Partitioning of Fish Host Resources. ECOLOGICAL MODELLING. Elsevier Science BV, Amsterdam, Netherlands, 201(2):171-178, (2007).
Abstract:	Riverine freshwater mussel species can be found in highly diverse communities where many similar species coexist. Mussel species potentially compete for food and space as adults, and for fish host resources during the larval (glochidial) stage. Resource partitioning at the larval stage may promote coexistence. A model of resource utilization was developed for two mussel species and analyzed to determine conditions for coexistence. Mussel species were predicted to coexist when they differed in terms of their success in contacting different fish host species; very similar strategies offered limited possibilities for coexistence. Differences in the mussel species' maximum infestation loads on the fish hosts that coincided with differences in their fish host contact success promoted coexistence. Mussel species with a given set of trade-offs in fish host use were predicted to coexist only for a subset of relative fish host abundances, so a shift in relative fish host abundances could result in the loss of a mussel species. An understanding of the conditions for freshwater mussel species coexistence can help explain high mussel diversity in rivers and guide ongoing conservation activities.

JOURNAL	Quantification of Fluorotelomer-Based Chemicals in Mammalian Matrices By Monitoring Perfluoroalkyl Chain Fragments With Gc/MS	02/01/2007

HENDERSON, W. M., E. J. WEBER, S. E. DUIRK, J. W. WASHINGTON, AND M. A. SMITH. Quantification of Fluorotelomer-Based Chemicals in Mammalian Matrices By Monitoring Perfluoroalkyl Chain Fragments With Gc/MS. Journal of Chromatography B. Elsevier Science Ltd, New York, NY, 846(1-2):155-161, (2007).
Abstract:	Perfluorocarboxylic acids (PFCAs), namely perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA), have been identified as persistent, bioaccurnulative and potentially toxic compounds. The structural analog, 8-2 fluorotelomer alcohol (8-2 FTOH) is considered the probable precursor of these stable metabolites. Because simultaneous quantification is needed for volatile and non-volatile perfluorinated chemicals (PFCs) in complex matrices, a GC/MS method was developed and tested based on selected ion monitoring of perfluorinated alkyl parent chain fragment ions. Although the method requires a derivatization step, combined GC/MS analysis of PFCA -me's and FTOHs increases analytical efficiency and decreases sample analysis time. The method instrument detection limits are between 7.1 and 24.5 ng/mL extract (MTBE), and the method quantification limits are below 50 ng/mL serum or ng/g liver for all PFCs investigated. Recoveries from mouse serum and liver homogenates, which were spiked with FTOHs and PFCAs at levels of 25 and 200 ng/mL or ng/g, ranged from 81 to 101%. Finally, the utility of the method was demonstrated by dosing male CD-I mice with 30 mg/kg-BW of 8-2 FTOH and quantifying PFCs 6 h post-treatment. The advantages of this method are (1) the simultaneous detection of both volatile and non-volatile fluorotelomer-based chemicals in complex matrices such as mammalian tissues, (2) as a confirmatory method to LC-MS/MS, and (3) as an alternative method of analysis for laboratories without access to LC-MS/MS.

JOURNAL	Use of Habitat-Contamination Spatial Correlation to Determine When to Perform a Spatially Explicit Ecological Risk Assessment	03/23/2007

PURUCKER, S. T., C. J. WELSH, R. N. STEWART, AND P. STARZEC. Use of Habitat-Contamination Spatial Correlation to Determine When to Perform a Spatially Explicit Ecological Risk Assessment. ECOLOGICAL MODELLING. Elsevier Science BV, Amsterdam, Netherlands, 204(1-2):180-192, (2007).
Abstract:	Anthropogenic contamination is typically distributed heterogeneously through space. This spatial structure can have different effects on the cumulative doses of individuals exposed to contamination within the environment. These effects are accentuated when individuals pursue different movement strategies, and movement strategies can be affected by how individuals and species value habitat. Habitat quality is often neglected when ecological risk assessments are performed, despite evidence that inclusion of a quantitative habitat measure can have a significant effect on the overall exposure estimate. We couple an exposure model with habitat data to examine the interactions between habitat preferences, the spatial distribution of contamination, and the resulting impact on dose estimates. Dose distributions are constructed for pronghorn (Antilocapra americana) exposed to fluoride when foraging on desert sagebrush. The results show the magnitude of the difference between simulated doses when foraging concentrations are positively or negatively correlated with different spatial distributions of habitat preferences. Mean estimated exposures obtained from non-spatial versus spatial methods can vary by a factor greater than two, and variation within the movement model, due to different habitat preferences, can vary by an order of magnitude. Such differences in calculated exposures can change the decision from no-action to remediation, or vice-versa, and impact the remedial design when cleanup is required. Results presented here are generally applicable to other terrestrial exposure situations. These simple model results demonstrate that examining the strength of the spatial correlation between habitat preference and contaminant data can be quickly used to determine when the implementation of a spatially explicit ecological risk assessment is useful.

JOURNAL	Diversity Surfaces and Species Wave Fronts in a Soil Microarthropod Assemblage: Adding the Dimension of Time	01/04/2007

JOHNSTON, J. M. Diversity Surfaces and Species Wave Fronts in a Soil Microarthropod Assemblage: Adding the Dimension of Time. Pedobiologia. Elsevier Science, New York, NY, 50(6):527-533, (2007).
Abstract:	As a general rule, animal species of intermediate size within a given taxonomic group are most abundant in nature. It is not known if these patterns occur in small-bodied taxa, such as soil microarthropods, or how these patterns change through time. Here I show that Oribatida (Acari), the most abundant and diverse arthropod fauna of coniferous forest soils, exhibit this pattern. However, the pattern is more complex than reported for other arthropods. I analyzed the total species surface comprising 6613 individuals and 54 species by forest stand. The underlying pattern consists of 15-year stands and 30-year stands forming two distinct and separated maxima. These results suggest that assemblage patterns form early in the development of ecological communities, and that these patterns appear within the soil assemblage as waves propagating in species - abundance - body size space during forest development. These results also support the assertion that undescribed species will likely be of intermediate size within a group. This analysis contributes to investigations of biodiversity and body size relationships by adding the temporal dimension. Potential applications are in disturbance and indicator studies or other work where changes in assemblage structure are used as measures of disturbance or as response variables in manipulative studies.

JOURNAL	Perfluorooctanoic Acid and Perfluorononanoic Acid in Fetal and Neonatal Mice Following in Utero Exposure to 8-2 Fluorotelomer Alcohol	02/01/2007

HENDERSON, W. M. AND M. A. SMITH. Perfluorooctanoic Acid and Perfluorononanoic Acid in Fetal and Neonatal Mice Following in Utero Exposure to 8-2 Fluorotelomer Alcohol. TOXICOLOGICAL SCIENCES. Society of Toxicology, 95(2):452-461, (2007).
Abstract:	8-2 fluorotelomer alcohol (FTOH) and its metabolites, perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA), are developmental toxicants, but metabolism and distribution during pregnancy is not known. To examine this, timed-pregnant mice received a single gavage dose (30 mg 8-2 FTOH/kg BW) on gestational day (GD) 8. Maternal and neonatal serum and liver as well as fetal and neonatal homogenate extracts were analyzed using GC/MS. During gestation (GD9 to GD18), maternal serum and liver concentrations of PFOA decreased from 789±41 to 668±23 ng/mL and from 673±23 to 587±55 ng/g, respectively. PFOA was transferred to the developing fetuses as early as 24 hours post-treatment with concentrations increasing from 45±9 ng/g (GD10) to 140±32 ng/g (GD18), while PFNA was quantifiable only at GD18 (31±4 ng/g). Post-partum, maternal serum PFOA concentrations decreased from 451±21 ng/mL post-natal day (PND) 1 to 52±19 ng/mL (PND15) and PFNA concentrations, although 5-fold less, exhibited a similar trend. Immediately after birth, pups were cross-fostered with dams that had been treated during gestation with 8-2 FTOH (T) or vehicle (C) resulting in four treatment groups in which the first letter represents in utero (fetal) exposure and the second represents lactational (neonatal) exposure: C/C, T/C, C/T, T/T. On PND1, neonatal whole-body homogenate concentrations of PFOA from T/T and T/C groups averaged 200±26 ng/g, decreased to 149±19 ng/g at PND3 and this decreasing trend was seen in both neonatal liver and serum from PND3 to PND15. Based on detectible amounts of PFOA in neonatal serum in the C/T group on PND3 (57±11 ng/mL) and on PND15 (58±3 ng/mL), we suggest the neonates were exposed through lactation. In conclusion, exposure of neonates to PFOA and PFNA occur both pre- and post-natally following maternal 8-2 FTOH exposure on GD8.

JOURNAL	Estimation of Phosphate Ester Hydrolysis Rate Constants. II. Acid and General Base Catalyzed Hydrolysis	05/01/2007

WHITESIDE, T. S., S. H. HILAL, AND L. A. CARREIRA. Estimation of Phosphate Ester Hydrolysis Rate Constants. II. Acid and General Base Catalyzed Hydrolysis. QSAR & COMBINATORIAL SCIENCE. John Wiley & Sons, Ltd., Indianapolis, IN, 26(5):587-595, (2007).
Abstract:	SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to calculate acid and neutral hydrolysis rate constants of phosphate esters in water. The rate is calculated from the energy difference between the initial and transition states of a molecule. This difference is a function of the reference rate and internal and external perturbations to the reference rate. The internal perturbations are comprised of electrostatic and resonance effects. The external perturbations quantify solute-solvent interactions based on the dielectric constant of the solvent and the steric effect of substituent groups. The general base hydrolysis model has been tested against 89 observed hydrolysis rate constants at multiple temperatures. The RMS deviation of the calculated versus observed values was 1.08 log M^-1 s^-1. The acid hydrolysis model has been tested on 83 rate constants over a variety of temperatures. The RMS deviation of the acid hydrolysis model was 0.41 log M^-1 s^-1.

JOURNAL	In Vitro Metabolism of the Fungicide and Environmental Contaminant Trans-Bromuconazole and Implications for Risk Assessment	01/15/2007

MAZUR, C. S., J. F. KENNEKE, C. T. STEVENS, M. S. OKINO, AND J. C. LIPSCOMB. In Vitro Metabolism of the Fungicide and Environmental Contaminant Trans-Bromuconazole and Implications for Risk Assessment. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH - PART A: CURRENT ISSUES. Taylor & Francis, Inc., Philadelphia, PA, 70(14):1241-1250, (2007).
Abstract:	Trans-Bromuconazole is a chiral chemical representative of a class of triazole-derivatives known to inhibit specific fungal cytochrome P450 (CYP) reactions. Kinetic measurements and delineation of metabolic pathways for triazole chemicals within in vitro hepatic microsomes are needed for accurate risk assessment and predictive in vivo physiological modeling. The current studies were conducted with rat liver microsomes to determine Michaelis-Menten saturation kinetic parameters (Vmax and KM ) for trans-bromuconazole using both substrate depletion and product formation reaction velocities. Kinetic parameters determined for trans-bromuconazole depletion at varying protein levels incubated at physiological temperature 37 degress C resulted in a KM value of 1.69 micro M and a Vmax value of 1398 pmole/min/mg protein. The concomitant linear formation of two metabolites identified using LC/MS-TOF and LC-MS/MS indicated hydroxylation of the trans-bromuconazole dichlorophenyl ring moiety. KM values determined for the hydroxylated metabolites were 0.87 and 1.03 micro M, with Vmax values of 449 and 694 pmole/min/mg protein, respectively. Chemical inhibition assays and studies conducted with individual purified human recombinant enzymes indicated the CYP3A subfamily was primarily responsible for biotransformation of the parent substrate. Additionally, trans-bromuconazole was found to undergo stereoselective metabolism as evidenced by a change in the enantiomeric ratio (trans-/trans +) with respect to time.

JOURNAL	Use of Δ¹³c, Δ¹⁵n and Carbon to Nitrogen Ratios to Evaluate the Impact of Sewage Derived Particulate Organic Matter on the Benthic Communities of the Southern California Bight	11/01/2007

RAMIREZ-ALVAREZ, N., J. V. MACIAS-ZAMORA, R. A. BURKE, AND L. V. RODRIGUEZ-VILLANUEVA. Use of Δ¹³c, Δ¹⁵n and Carbon to Nitrogen Ratios to Evaluate the Impact of Sewage Derived Particulate Organic Matter on the Benthic Communities of the Southern California Bight. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 26(11):2332-2338, (2007).
Abstract:	We present stable isotope (δ¹³C and δ¹⁵N) measurements of particulate organic matter (POM) sources and benthic organic matter (OM) compartments, and sediment C/N ratios from the coastal area of the southern end of the Southern California Bight (SCB). We use the isotopic values to evaluate the relative importance of the major POM sources to the sediment and two benthic macroinvertebrates. Application of a simple model to sediment δ¹³C values suggests that sewage derived POM (SDPOM) supplies an average of 48% of the organic carbon to study area sediments. Application of a similar model to Spiophanes duplex δ¹³C values suggests that SDPOM from wastewater treatment plants discharging into the SCB could supply up to 28 % of the C assimilated by this important benthic macroinvertebrates in areas as far away as 26 km from SDPOM inputs. The Amphiodia urtica stable isotope data are more difficult to interpret because of the complex feeding habits of this organism.

JOURNAL	Evaluating Regional Predictive Capacity of a Process-Based Mercury Exposure Model, Regional-Mercury Cycling Model (R-Mcm), Applied to 91 Vermont and New Hampshire Lakes and Ponds, USA	04/01/2007

KNIGHTES, C. D. AND R. B. AMBROSE. Evaluating Regional Predictive Capacity of a Process-Based Mercury Exposure Model, Regional-Mercury Cycling Model (R-Mcm), Applied to 91 Vermont and New Hampshire Lakes and Ponds, USA. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 26(4):807-815, (2007).
Abstract:	Regulatory agencies must develop fish consumption advisories for many lakes and rivers with limited resources. Process-based mathematical models are potentially valuable tools for developing regional fish advisories. The Regional Mercury Cycling model (R-MCM) was specifically designed to model a series of lakes for a given region with site-specific data and parameterization for each application. In this paper, we explore the feasibility of R-MCM application to develop regional fish advisories from existing data by testing model performance across 91 Vermont (VT) and New Hampshire (NH) (both in USA) lakes. We use a progressive method of parameter refinement ranging from simple defaults specified by the model to site-specific parameterization to evaluate potential improvements in model prediction. Model applications and parameter refinement tiers are based on Regional Environmental Monitoring Assessment Program (REMAP) data. Results show that R-MCM generally under-predicts water column methylmercury and total mercury concentrations and over-predicts sediment methylmercury concentrations. Default level input parameterization produced the largest amount of random scatter in model forecasted values. Using site-specific values for the default level characteristics reduced this variability but did not improve overall model performance. By separating the observed and predicted data by lake characteristics, we identify some overall trends in bias and fit, but are unable to identify systematic biases in model performance by lake type. This analysis suggests that process based models like R-MCM cannot be used for a priori predictive applications at the regional scale at this time. Further, this work reinforces the need for additional research on the transport and transformation of mercury to elucidate parameterization useable in a modeling framework to help refine predictive capabilities of process based models.

JOURNAL	Production of Hydrated Electrons from Photoionization of Dissolved Organic Matter in Natural Waters	03/01/2007

WANG, W., O. C. ZAFIRIOU, I. Y. CHAN, R. G. ZEPP, AND N. V. BLOUGH. Production of Hydrated Electrons from Photoionization of Dissolved Organic Matter in Natural Waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 41(5):1601-1607, (2007).
Abstract:	Under UV irradiation, an important primary photochemical reaction of colored dissolved organic matter (CDOM) is electron ejection, producing hydrated electrons (e-aq). The efficiency of this process has been studied in both fresh and seawater samples with both steady-state scavenger (SS-S) and time-resolved laser flash photolysis (LFP) methods. However, the apparent quantum yields (AQYs) of (e-aq) for the same samples using the two methods differ by as much as a factor of 100, calling for a closer re-examination of how the process is measured. We developed a highly sensitive multi-pass LFP apparatus that allows detection of transient species at very low and variable UV irradiation intensities. Under single-photon conditions, we measured the AQY from Laurentian fulvic acid as 1.3 x 10(-4), and set the upper limit for other CDOM samples at 6 x 10(-5), bringing the LFP results very close to those from SS-S methods. We also examined the ionization at elevated irradiation intensities and clearly demonstrated that multiphoton ionization occurs at intensities well below those usually used in LFP experiments. The multiphoton ionization is probably the cause of the high AQYs reported by earlier LFP work. In addition, we also observed in real time other photochemical reactions, such as triplet quenching and bleaching, in the single photon regime.

JOURNAL	Calibration and Evaluation of a Mercury Model for a Western Stream and Constructed Wetland	05/09/2007

BROWN, S., L. SAITO, C. D. KNIGHTES, AND M. GUSTIN. Calibration and Evaluation of a Mercury Model for a Western Stream and Constructed Wetland. WATER, AIR, AND SOIL POLLUTION. Springer, New York, NY, 182(1-4):275-290, (2007).
Abstract:	Numerous studies have shown that Steamboat Creek in Nevada is highly contaminated with mercury, with aqueous mercury concentrations more than two orders of magnitude greater than nearby mountain streams. One objective of this study was to determine if the new Spreadsheet-based Ecological Risk Assessment for the Fate of Mercury (SERAFM) model could be calibrated to the concentrations of unfiltered and dissolved total mercury, and unfiltered and dissolved MeHg in the water column for a reach on SBC and a related constructed wetland mesocosm for different seasons and residence times. SERAFM is a new U.S. Environmental Protection Agency steady state, single segment, mass balance mercury model that has been applied to lakes, and this study also examined the model's applicability for modeling an arid flowing water environment in different seasons. The average combined error between observed and model-estimated mercury concentrations was 12 percent and 17 percent for the reach and mesocosm, respectively. Some recommendations are proposed that may allow SERAFM to better model flowing systems.

JOURNAL	Interactive Effects of Solar UV Radiation and Climate Change on Biogeochemical Cycling	03/08/2007

ZEPP, R. G., D. J. ERICKSON III, N. D. PAUL, AND B. SULZBERGER. Interactive Effects of Solar UV Radiation and Climate Change on Biogeochemical Cycling. PHOTOCHEMICAL AND PHOTOBIOLOGICAL SCIENCES. Royal Society of Chemistry, Cambridge, Uk, 6(3):286-300, (2007).
Abstract:	This paper assesses research on the interactions of UV radiation (280-400 nm) and global climate change with global biogeochemical cycles at the Earth's surface. The effects of UV-B (280-315 nm), which are dependent on the stratospheric ozone layer, on biogeochemical cycles are often linked to concurrent exposure to UV-A radiation (315-400 nm), which is influenced by global climate change. These interactions involving UV radiation (the combination of UV-B and UV-A) are central to the prediction and evaluation of future Earth environmental conditions. There is increasing evidence that elevated UV-B radiation has significant effects on the terrestrial biosphere with implications for the cycling of carbon, nitrogen and other elements. The cycling of carbon and inorganic nutrients such as nitrogen can be affected by UV-B-mediated changes in communities of soil organisms, probably due to the effects of UV-B radiation on plant root exudation and/or the chemistry of dead plant material falling to the soil.

JOURNAL	Haloacetonitriles Vs. Regulated Haloacetic Acids: Are Nitrogen Containing DBPs More Toxic?	01/15/2007

MUELLNER, M. G., E. D. WAGNER, K. MCCALLA, S. D. RICHARDSON, Y. WOO, AND M. J. PLEWA. Haloacetonitriles Vs. Regulated Haloacetic Acids: Are Nitrogen Containing DBPs More Toxic? ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 41(2):645-651, (2007).
Abstract:	Haloacetonitriles (HANs) are toxic nitrogenous drinking water disinfection by-products (N-DBPs) and are observed with chlorine, chloramine, or chlorine dioxide disinfection. Using microplate-based Chinese hamster ovary (CHO) cell assays for chronic cytotoxicity and acute genotoxicity, we analyzed 7 HANs: iodoacetonitrile (IAN), bromoacetonitrile (BAN), dibromoacetonitrile (DBAN), bromochloroacetonitrile (BCAN), chloroacetonitrile (CAN), dichloroacetonitrile (DCAN), and trichloroacetonitrile (TCAN). As a chemical class, the HANs are more toxic than regulated DBPs, such as the haloacetic acids. The toxicity of N-DBPs may become a health concern because of the increased use of alternative disinfectants, such as chloramines, which may enhance the formation of N-DBPs, including HANs.

JOURNAL	Temporal Moisture Content Variability Beneath and External to a Building and the Potential Effects on Vapor Intrusion Risk Assessment	06/15/2007

TILLMAN, F. AND J. W. WEAVER. Temporal Moisture Content Variability Beneath and External to a Building and the Potential Effects on Vapor Intrusion Risk Assessment. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier Science Ltd, New York, NY, 379(1):1-15, (2007).
Abstract:	Migration of vapors from organic chemicals residing in the subsurface into overlying buildings is known as vapor intrusion. Because of the difficulty in evaluating vapor intrusion by indoor air sampling, models are often employed to determine if a potential indoor inhalation exposure pathway exists and, if such a pathway is complete, whether long-term exposure increases the occupants' risk for cancer or other toxic effects to an unacceptable level. For site-specific vapor intrusion assessments, moisture content is, at times, determined from soil cores taken in open spaces between buildings. However, there is little published information on how moisture content measured outside a building structure compares with the moisture content directly beneath the building - where the values are most critical for vapor intrusion assessments. This research begins to address these issues by investigating the movement of soil moisture next to and beneath a building at a contaminated field site and determining the effect on vapor intrusion risk assessment. A 2-dimensional, variably-saturated water flow model, HYDRUS-2D, is used with 2 years of hourly, local rainfall data to simulate subsurface moisture content in the vicinity of a hypothetical 10×10-m building slab at a contaminated field site. These moisture content values are used in vapor intrusion risk assessment simulations using the Johnson and Ettinger model with instantaneous and averaged moisture contents. Results show that vapor intrusion risk assessments based on moisture content determined from soil cores taken external to a building structure may moderately-to-severely underestimate the vapor intrusion risk from beneath the structure. Soil under the edges of a slab may be influenced by rainfall events and may show reduced vapor intrusion risk as a consequence. Data from a building instrumented with subslab moisture probes showed results similar to the modeling, but with a smaller difference between the subslab and outside average moisture contents. These results indicate that, depending upon the point of vapor ingress into the structure and soil type, risk-based cleanup concentrations based on outside-of-slab or default moisture content values may not be predictive of exposure to organic vapors from below a building.

JOURNAL	Analytic Element Ground Water Modeling as a Research Program (1980-2006)	07/11/2007

KRAEMER, S. R. Analytic Element Ground Water Modeling as a Research Program (1980-2006). GROUND WATER. National Ground Water Association, Westerville, OH, 45(4):402-408, (2007).
Abstract:	Scientists and engineers who use the analytic element method (AEM) for solving problems of regional ground water flow may be considered a community, and this community can be studied from the perspective of history and philosophy of science. Applying the methods of the Hungarian philosopher of science Imre Lakatos (1922-1974), the AEM research program is distinguished by its hard core (theoretical basis), protective belt (auxiliary assumptions), and heuristic (problem solving machinery). AEM has emerged relatively recently in the scientific literature and has a relatively modest number of developers and practitioners compared to the more established finite element and finite difference methods. Nonetheless, there is evidence to support the assertion that the AEM research program remains in a progressive phase. The evidence includes an expanding publication record, a growing research strand following Professor Otto Strack's book Groundwater Mechanics (1989), the continued placement of AEM researchers in academia, and the further development of innovative analytic solutions and computational solvers/models.

JOURNAL	Analysis of Perfluorinated Carboxylic Acids in Soils: Detection and Quantitation Issues at Low Concentrations	06/01/2007

WASHINGTON, J. W., J. J. ELLINGTON, T. JENKINS, AND J. J. EVANS. Analysis of Perfluorinated Carboxylic Acids in Soils: Detection and Quantitation Issues at Low Concentrations. JOURNAL OF CHROMATOGRAPHY A. Elsevier Science Ltd, New York, NY, 1154(1-2):111-120, (2007).
Abstract:	Methods were developed for the extraction from soil, identification, confirmation and quantitation by LC/MS/MS of trace levels of perfluorinated octanoic acid (PFOA), perfluorinated nonanoic acid (PFNA) and perfluorinated decanoic acid (PFDA). Whereas PFOA, PFNA and PFDA all can be quantitated using the method of standard additions, PFOA also can be quantitated less laboriously using 13C4-PFOA as a matrix internal standard. The impact of extract matrices on signal varied between soils and temporally during analytical runs rendering 13C4-PFOA unsuitable as a matrix internal standard for quantitating perfluorinated carboxylic acids (PFCAs) other than PFOA, which co-elutes with 13C4-PFOA. In fact, for soil extracts quantitation of PFCAs based on external calibrations proved about as accurate as use of matrix internal standards for target analytes that do not co-elute with the matrix internal standard. Also, 13C4-PFOA should be used carefully as a matrix internal standard for trace levels of PFOA because some 13C4-PFOA standards contain trace impurities of unlabelled PFOA. When the presence of PFCAs in soil extracts is being determined by LC/MS/MS, detection limits are best defined by statistical methods that quantify the significance of contrast between analytical signal and background noise using multiple analyses. Further, when developing a calibration of low concentrations using weighted regression, the central tendency of the calibration line is best fitted using graphical depictions of error. As the MDL for the transition-product quantitation ion is approached in LC/MS/MS, relatively weak signals of transition-product confirmation ions can be used as a rejection criterion by looking for anomalously high values of the ratio of the confirmation to the quantitation ion.

JOURNAL	Seasonal Variations in River Discharge and Nutrient Export to a Northeastern Pacific Estuary	03/26/2007

SIGLEO, A. C. AND W. E. FRICK. Seasonal Variations in River Discharge and Nutrient Export to a Northeastern Pacific Estuary. ESTUARINE, COASTAL AND SHELF SCIENCE. Elsevier Science Ltd, New York, NY, 73(3-4):368-378, (2007).
Abstract:	Seasonal variations in dissolved nitrogen and silica loadings were related to seasonal variability in river discharge. Dissolved nutrient concentrations measured weekly at three stations in the Yaquina River, Oregon from 1999 through 2001, and then monthly in 2002 were used as the basis for developing a nutrient loading regression as part of a larger agency program for evaluating nutrient processes. Because realistic models of nutrient transport require dense data sets to capture both long and short term fluctuations in nutrient concentrations, data at one freshwater station also were collected hourly for the same years using an in-stream monitor. The effects of storm events on dissolved nutrient transport were examined during three storms, including one in a high rainfall-discharge year, and two in average years, one of which followed a drought year. During the drought year (WY2001), total dissolved nitrate input was considerably less than in wetter years. Dissolved nitrate concentrations, however, were unusually high in the first winter storm runoff after the drought. The freshwater dissolved nitrate nitrogen loads varied from 40,380 kg day 1 during a high flow storm event to 0.11 kg day-1 during late summer, low flow conditions. Dissolved silica dynamics differed from those of nitrate because during storm events, silica concentrations in the Yaquina River decreased to near zero at the storm height, probably due to dilution by near surface or overland flow, and later recovered. During the time interval studied, over 94% of the dissolved nitrate and silica were transported from the watershed during the winter months of greater rainfall, indicating that seasonality and river flow are primary factors when considering nutrient loadings from this watershed system.

JOURNAL	Some Statistical Issues Related to Multiple Linear Regression Modeling of Beach Bacteria Concentrations	03/15/2007

GE, Z. AND W. E. FRICK. Some Statistical Issues Related to Multiple Linear Regression Modeling of Beach Bacteria Concentrations. ENVIRONMENTAL RESEARCH. Academic Press Incorporated, Orlando, FL, 103(3):358-364, (2007).
Abstract:	As a fast and effective technique, the multiple linear regression (MLR) method has been widely used in modeling and prediction of beach bacteria concentrations. Among previous works on this subject, however, several issues were insufficiently or inconsistently addressed. Those issues include the value and use of interaction terms, the serial correlation, the criteria for model selection, and model assessment. The present work shows that serial correlations, as often present in sequentially observed data records, deserve full attention from the modeler. The testing and adjustment for the time-series effect should be implemented in a statistically rigorous framework.

JOURNAL	Research Activities at U.S. Government Agencies in Subsurface Reactive Transport Modeling	11/20/2007

CYGAN, R. T., C. T. STEVENS, R. PULS, S. B. YABUSAKI, R. D. WAUCHOPE, C. J. MCGRATH, G. P. CURTIS, M. D. SIEGEL, L. A. VEBLEN, AND D. R. TURNER. Research Activities at U.S. Government Agencies in Subsurface Reactive Transport Modeling. Vadose Zone Journal. Soil Science Society of America, Madison, WI, 6(4):805-822, (2007).
Abstract:	The fate of contaminants in the environment is controlled by both chemical reactions and transport phenomena in the subsurface. Our ability to understand the significance of these processes over time requires an accurate conceptual model that incorporates the various mechanisms of coupled chemical and physical processes. Adsorption, desorption, ion exchange, precipitation, dissolution, growth, solid solution, redox, microbial activity, and other processes are often incorporated into reactive transport models for the prediction of contaminant fate and transport. U.S. federal agencies utilize such models to evaluate contaminant transport and provide guidance to decision makers and regulators for treatment issues. Summaries of selected research projects and programs are provided to demonstrate the level of activity in various applications and to present examples of recent advances in subsurface reactive transport modeling.

JOURNAL	Estuarine-Ocean Exchange in a North Pacific Estuary: Comparison of Steady State and Dynamic Models	08/01/2007

FRICK, W. E., T. KHANGAONKAR, A. C. SIGLEO, AND Z. YANG. Estuarine-Ocean Exchange in a North Pacific Estuary: Comparison of Steady State and Dynamic Models. Estuarine Coastal and Shelf Science. Elsevier Science Ltd, New York, NY, 74(1-2):1-11, (2007).
Abstract:	Nutrient levels in coastal waters must be accurately assessed to determine the nutrient effects of increasing populations on coastal ecosystems. To accomplish this goal, in-field data with sufficient temporal resolution are required to define nutrient sources and sinks, and to ultimately calculate nutrient budgets. Models then are required for the interpretation and analysis of data sets. To quantify the coastal ocean nitrogen input to Yaquina Bay, Oregon, nitrate concentrations were measured by a moored sensor hourly for one month during summer upwelling some distance outside the estuary entrance jetties. The time series results then were interpreted using a steady state model (Visual Plumes' PDSW) and a hydrodynamic model, the Finite Volume Coastal Ocean Model (FVCOM). The results showed that the steady-state plume model simulates observed velocity and concentration data fairly well during periods of strong discharge velocity and weak ambient coastal currents. FVCOM was judged to give better estimates under all other ambient current conditions, although the data from the mooring cannot be used to prove this assertion as stronger currents would deflect the plume away from the mooring. Nevertheless, plume models may be useful in establishing boundary and initial conditions for hydrodynamic models.

JOURNAL	Toxicity of Fipronil and Its Enantiomers to Marine and Freshwater Non-Targets	06/01/2007

OVERMYER, J. P., D. R. ROUSE, A. W. GARRISON, J. K. AVANTS, M. E. DELORENZO, K. W. CHUNG, P. B. KEY, W. A. WILSON, AND M. C. BLACK. Toxicity of Fipronil and Its Enantiomers to Marine and Freshwater Non-Targets. Journal of Environmental Science and Health. Part B, Pesticides, Food Contaminants, and Agricultural Wastes. Marcel Dekker Incorporated, New York, NY, 42(5):471-480, (2007).
Abstract:	Fipronil is a phenylpyrazole insecticide used in agricultural and domestic settings for controlling various insect pests in crops, lawns, and residential structures. Fipronil is chiral; however, it is released into the environment as a racemic mixture of two enantiomers. In this study, the acute toxicity of the (S,+) and (R,-) enantiomers and the racemic mixture of fipronil were assessed using Simulium vittatum IS-7 (black fly), Xenopus laevis (African clawed frog), Procambarus clarkii (crayfish), Palaemonetes pugio (grass shrimp), Mercenaria mercenaria (hardshell clam), and Dunaliella tertiolecta (phytoplankton). Results showed that S. vittatum IS-7 was the most sensitive freshwater species to the racemic mixture of fipronil (LC50 = 0.65 µg/L) while P. pugio was the most sensitive marine species (LC50 = 0.32 µg/L). Procambarus clarkii were significantly more sensitive to the (S,+) enantiomer while larval P. pugio were significantly more sensitive to the (R,-) enantiomer. Enantioselective toxicity was not observed in the other organisms tested. Increased mortality and minimal recovery was observed in all species tested for recovery from fipronil exposure. These results indicate that the most toxic isomer of fipronil is organism specific and that enantioselective toxicity may be more common in crustaceans than in other aquatic organisms.

JOURNAL	Water Analysis: Emerging Contaminants and Current Issues: 2007 Review	06/15/2007

RICHARDSON, S. D. Water Analysis: Emerging Contaminants and Current Issues: 2007 Review. ANALYTICAL CHEMISTRY. American Chemical Society, Washington, DC, 79(12):4295-4324, (2007).
Abstract:	This biennial review covers developments in Water Analysis over the period of 2005-2006. A few significant references that appeared between January and March 2007 are also included. Analytical Chemistry's current policy is to limit reviews to include 200-250 significant references and to focus on new trends. As a result, as was done in the previous 2005 Water Analysis review, this 2007 review is limited to new, emerging contaminants and environmental issues that are driving most of the current research. Even with a narrow focus, only a small fraction of the quality research publications could be discussed. As a result, this review will not be comprehensive, but will highlight new areas and discuss representative papers in the areas of focus.

JOURNAL	Raman Spectroscopy-Based Metabolomics for Differentiating Exposures to Triazole Fungicides Using Rat Urine	10/01/2007

CHERNEY, D., D. R. EKMAN, D. J. DIX, AND T. W. COLLETTE. Raman Spectroscopy-Based Metabolomics for Differentiating Exposures to Triazole Fungicides Using Rat Urine. ANALYTICAL CHEMISTRY. American Chemical Society, Washington, DC, 79(19):7324-7332, (2007).
Abstract:	Normal Raman spectroscopy was evaluated as a metabolomic tool for assessing the impacts of exposure to environmental contaminants, using rat urine collected during the course of a toxicological study. Specifically, one of three triazole fungicides, myclobutanil, propiconazole or triadimefon, was administered daily via oral gavage to male Sprague-Dawley rats at doses of 300, 300, or 175 mg/kg, respectively. Urine was collected from all three treatment groups and also from vehicle control rats on day six, following five consecutive days of exposure. Spectra were acquired with a CCD-based dispersive Raman spectrometer, using 785nm diode-laser excitation. To optimize the signal-to-noise ratio, urine samples were filtered through a stirred ultrafiltration cell with a 500 nominal molecular weight limit filter to remove large, unwanted urine components that can degrade the spectrum via fluorescence. However, a subsequent investigation suggested that suitable spectra can be obtained in a high-throughput fashion, with little or no Raman-specific sample preparation. For sake of comparison, a parallel 1H-NMR- based metabolomic analysis was also conducted on the unfiltered samples. Results from multivariate data analysis demonstrated that the Raman method compares favorably with NMR in regard to the ability to differentiate responses from these three contaminants.

JOURNAL	Parameter Sets for Upper and Lower Bounds on Soil-to-Indoor-Air Contaminant Attenuation Predicted By the Johnson and Ettinger Vapor Intrusion Model	09/15/2007

TILLMAN, F. D. AND J. W. WEAVER. Parameter Sets for Upper and Lower Bounds on Soil-to-Indoor-Air Contaminant Attenuation Predicted By the Johnson and Ettinger Vapor Intrusion Model. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 41(27):5797-5806, (2007).
Abstract:	Migration of volatile chemicals from the subsurface into overlying buildings is known as vapor intrusion (VI). Under certain circumstances, people living in homes above contaminated soil or ground water may be exposed to harmful levels of these vapors. A popular VI screening-level algorithm widely used in the United States, Canada and the U.K. to assess this potential risk is the Johnson and Ettinger (J&E) model. Concern exists over using the J&E model for deciding whether or not further action is necessary at sites as many parameters are not routinely measured (or are un-measurable). Using EPA-recommended ranges of parameter values for nine soil-type/source depth combinations, input parameter sets were identified that correspond to best and worst case results of the J&E model. The results established the existence of generic best and worst case parameter sets for maximum and minimum exposure for all soil types and depths investigated. Using the generic worst case/best case parameter sets, an analysis can be performed that, given the limitations of the input ranges and the model, bounds the indoor air exposures in a vapor intrusion investigation.

JOURNAL	Enantioselective Microbial Transformation of the Phenylpyrazole Insecticide Fipronil in Anoxic Sediments	12/15/2007

JONES, W. J., C. S. MAZUR, J. F. KENNEKE, AND A. W. GARRISON. Enantioselective Microbial Transformation of the Phenylpyrazole Insecticide Fipronil in Anoxic Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 41(24):8301-8307, (2007).
Abstract:	Fipronil, a chiral insecticide, was biotransformed initially to fipronil sulfide in anoxic sediment slurries following a short lag period. Sediment slurries characterized as either sulfidogenic or methanogenic transformed fipronil with half-lives of approximately 35 and 40 days, respectively. In all microbially active sediment slurries tested, transformation of fipronil to fipronil sulfide was enantioselective. In the sulfidogenic sediment slurry, the enantiomeric fraction (EF) of fipronil decreased from an initial racemic EF value of 0.46 to a value of 0.22 during the incubation period of active fipronil transformation, indicating preferential transformation of the (+)-enantiomer. A previously unidentified product, 5-NH2-4-CF3S-3-CONH2-1-[2,6-dichloro-4-(trifluoromethyl)phenyl] pyrazole, or fipronil sulfide-amide, was detected in the sulfidogenic slurries and coincided with the loss of fipronil sulfide. Biota from methanogenic freshwater sediment slurries also transformed fipronil enantioselectively but with a preference for the (-)-enantiomer. In all microbially inhibited (autoclaved) sediment slurries tested, no changes in the enantiomeric fractions of fipronil were observed and only low levels (less than 5% of the added fipronil) of the fipronil sulfide metabolite were detected. In defined (model) chemical experiments, solutions of pyrite (FeS2) and iron sulfide (FeS) non- enantioselectively transformed fipronil primarily to either 2,6-dichloro-4-(trifluoromethyl)- aniline or to fipronil sulfide and fipronil amide, respectively. This report provides the first experimental evidence of enantioselective microbial transformation of fipronil in a natural environment (soil, water, sediment) as well as identification of a novel fipronil biotransformation product.

JOURNAL	Nmr Analysis of Male Fathead Minnow Urinary Metabolites: A Potential Approach for Studying Impacts of Chemical Exposures	10/01/2007

EKMAN, D. R., Q. TENG, AND T. W. COLLETTE. Nmr Analysis of Male Fathead Minnow Urinary Metabolites: A Potential Approach for Studying Impacts of Chemical Exposures. AQUATIC TOXICOLOGY. Elsevier Science Ltd, New York, NY, 85(2):104-112, (2007).
Abstract:	The potential for profiling endogenous metabolites in urine from male fathead minnows (Pimephales promelas) to assess chemical exposures was explored using nuclear magnetic resonance (NMR) spectroscopy. Both one dimensional (1D) and two dimensional (2D) NMR spectroscopy was used for the assignment of metabolites in urine from unexposed fish. Because fathead minnow urine is dilute, we lyophilized these samples prior to analysis. Furthermore, 1D 1H-NMR spectra of unlyophilized fathead minnow and rat urine were acquired to allow comparison of relative water content and to compare rat and fish metabolite profiles. As a small proof-of-concept study, lyophilized urine samples from male fathead minnows exposed to three different concentrations of the antiandrogen vinclozolin were analyzed by 1D 1H-NMR to assess exposure-induced changes. Two partial least squares discriminant analysis (PLS-DA) models were constructed - one comparing the low-exposure class (100 g/L, nominal), and one comparing the high-exposure class (700 g/L, nominal), to controls. Weight loadings plots from these two models were used to determine changes in urinary metabolite profiles associated with the exposure. The results of this study demonstrate the potential utility of an NMR-based approach for assessing chemical exposures in male fathead minnow, using urine collected from individual fish.

JOURNAL	An Assessment of Thermodynamic Reaction Constants for Simulating Aqueous Environmental Monomethylmercury Speciation	11/01/2007

LOUX, N. T. An Assessment of Thermodynamic Reaction Constants for Simulating Aqueous Environmental Monomethylmercury Speciation. CHEMICAL SPECIATION AND BIOAVAILABILITY. Science and Technology Letters, 19(4):183-196, (2007).
Abstract:	Monomethylmercury (CH3Hg+) is both the most ecologically significant and the least well characterized species of mercury in environmental settings. Our understanding of the environmental speciation behavior of this compound is limited both as the result of lesser available laboratory data (when compared to inorganic mercury) as well as the uncertainties associated with our understanding of the properties of environmental ligands. Extensive carefully screened databases of reaction constants useful for describing the environmental speciation of inorganic mercury with inorganic ligands are already in existence (Sillen and Martell, 1964, 1971; Lindsay, 1979; Rai et al., 1986; Sadiq, 1992; Martell, Smith and Motekaitis, 1998, 2003). This work focuses on assessing the accuracy of the thermodynamic reaction constant database of the much less well characterized monomethyl compound.

JOURNAL	Occurrence, Genotoxicity, and Carcinogenicity of Emerging Disinfection By-Products in Drinking Water: A Review and Roadmap for Research	11/15/2007

RICHARDSON, S. D., M. J. PLEWA, E. D. WAGNER, R. S. SCHOENY, AND D. M. DEMARINI. Occurrence, Genotoxicity, and Carcinogenicity of Emerging Disinfection By-Products in Drinking Water: A Review and Roadmap for Research. MUTATION RESEARCH. Elsevier Science Ltd, New York, NY, 636(1-3):178-242, (2007).
Abstract:	Disinfection by-products (DBPs) are formed when disinfectants (chlorine, ozone, chlorine dioxide, or chloramines) react with naturally occurring organic matter, anthropogenic contaminants, bromide, and iodide during the production of drinking water. Here we review 30 years of research on the occurrence, genotoxicity, and carcinogenicity of 85 DBPs, 11 of which are currently regulated by the U.S., and 74 of which are considered emerging DBPs due to their moderate occurrence levels and/or toxicological properties. Our analysis identified 3 categories of DBPs of particular interest. Category 1 contains 8 DBPs with some or all of the toxicologic characteristics of human carcinogens: 4 regulated (bromodichloromethane, dichloroacetic acid, dibromoacetic acid, and bromate) and 4 unregulated DBPs (formaldehyde, acetaldehyde, MX, and NDMA). Categories 2 and 3 contain 43 emerging DBPs that are present at moderate levels (sub-low µg/L): category 2 contains the 26 of these that are genotoxic (including chloral hydrate, which is also a rodent carcinogen); and category 3 contains the remaining17 for which little or no toxicological data are available.

JOURNAL	Calculating Physical Properties of Organic Compounds for Environmental Modeling from Molecular Structure	12/21/2007

HILAL, S. H., A. N. SARAVANARAJ, T. WHITESIDE, AND L. A. CARREIRA. Calculating Physical Properties of Organic Compounds for Environmental Modeling from Molecular Structure. Journal of Computer-Aided Molecular Design. Springer, New York, NY, 21(12):693-708, (2007).
Abstract:	Mathematical models for predicting the transport and fate of pollutants in the environment require reactivity parameter values-- that is value of the physical and chemical constants that govern reactivity. Although empirical structure activity relationships have been developed that allow estimation of some constants, such relationships are generally valid only within limited families of chemicals. The computer program, SPARC, uses computational algorithms based on fundamental chemical structure theory to estimate a large number of chemical reactivity parameters and physical properties for a wide range of organic molecules strictly from molecular structure. Resonance models were developed and calibrated using measured light absorption spectra, whereas electrostatic interaction models were developed using measured ionization pKas in water. Solvation models (i.e., dispersion, induction, H-bonding, etc.) have been developed using various measured physical properties data. At the present time, SPARC's physical property models can predict vapor pressure and heat of vaporization (as a function of temperature), boiling point (as a function of pressure), diffusion coefficient (as a function of pressure and temperature), activity coefficient, solubility, partition coefficient and chromatographic retention time as a function of solvent and temperature. This prediction capability crosses chemical family boundaries to cover a broad range of organic compounds.

JOURNAL	Enhancing Hydrological Simulation Program Fortran Model Channel Hydraulic Representation	10/30/2007

MOHAMOUD, Y. M. Enhancing Hydrological Simulation Program Fortran Model Channel Hydraulic Representation. JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION. American Water Resources Association, Middleburg, VA, 43(5):1280-1292, (2007).
Abstract:	The Hydrological Simulation Program– FORTRAN (HSPF) is a comprehensive watershed model that employs depth-area - volume - flow relationships known as the hydraulic function table (FTABLE) to represent the hydraulic characteristics of stream channel cross-sections and reservoirs. An accurate FTABLE determination for a stream cross-section site requires an accurate determination of mean flow depth, mean flow width, roughness coefficient, longitudinal bed slope, and length of stream reach. A method that uses regional regression equations to estimate mean flow depth, mean flow width, and roughness coefficient is presented herein. FTABLES generated by the proposed method (Alternative Method) and FTABLES generated by BASINS were compared. As a result, the Alternative Method was judged to be an enhancement over the BASINS method. This study concludes that hydraulic calibration enhances suspended sediment simulation performance, but even greater improvement in suspended sediment calibration can be achieved when hydrological simulation performance is improved. Any improvements in hydrological simulation performance are subject to improvements in the temporal and spatial representation of the precipitation data.

JOURNAL	Drowning in Disinfection Byproducts? Swimming Pool Water Quality	11/01/2007

Zwiener, C., S. D. RICHARDSON, D. M. DEMARINI, T. Grummt, T. Glauner, AND F. Frimmel. Drowning in Disinfection Byproducts? Swimming Pool Water Quality. Water: Journal of the Australian Water Association. Australian Water Association, Wentworth Falls, Australia, 34(7):25-27, (2007).
Abstract:	Disinfection is mandatory for swimming pools, because transmission of disease by bacteria, virus and protozoa is the most significant health issue. However another issue arises, and care should be taken to minimize the risks from disinfection by-products (DBPs). Public pools are usually disinfected by gaseous chlorine or sodium hypochlorite; home pools typically use stabilized chlorine. The use of chlorine produces a variety of disinfection byproducts (DBPs), such as trihalomethanes (THMs), which have been detected in the blood and breath of swimmers and of nonswimmers at indoor pools. Also produced are halogenated acetic acids (HAAs) and haloketones, which irritate the eyes, skin, and mucous membranes; trichloramine, which is linked with swimming pool-associated asthma; and halogenated derivatives of UV sun screens, some of which show endocrine effects. Precursors of DBPs include human body substances, chemicals used in cosmetics and sun screens, and natural organic matter. A 1.6- 2.0-fold increased risk for bladder cancer has been associated with swimming or showering/bathing with chlorinated water. Bladder cancer risk from THM exposure (all routes combined) was greatest among those with the GSTT1-1gene. DBPs may be reduced by engineering and behavioral means, such as applying new oxidation and filtration methods, reducing bromide and iodide in the source water, increasing air circulation in indoor pools and assuring the cleanliness of swimmers. The positive health effects gained by swimming can be increased by reducing all potential adverse health risks.

JOURNAL	Managing Multimedia Pollution for a Multimedia World	12/01/2007

BABENDREIER, J. E., L. S. MATOTT, J. Hameedi, R. L. DENNIS, C. D. KNIGHTES, R. MATHUR, Y. M. MOHAMOUD, J. M. JOHNSTON, C. C. WEST, G. F. LANIAK, N. GABER, P. PASCUAL, AND R. ARAUJO. Managing Multimedia Pollution for a Multimedia World. EM: AIR AND WASTE MANAGEMENT ASSOCIATIONS MAGAZINE FOR ENVIRONMENTAL MANAGERS. Air & Waste Management Association, Pittsburgh, PA, 6-11, (2007).
Abstract:	Through modest attention to the information highway we ride upon each day, we are increasingly aware of the intent, actions, and reactions of local, state and Federal governments, regional compacts, and international organizations to protect the quality of the water we drink, the air we breathe, and the food we (and our pets) eat. Just as with the globalization of our economy, these scales of government interact in many ways, each from its own vantage point, to optimally manage or otherwise influence critical aspects of our multimedia world. As one example, we are currently witnessing a proliferation of resolutions and actions affirming county government support for addressing climate change. On the other end of the spectrum, most citizens are familiar with the successes of the international effort to control chlorofluorocarbons (CFCs) under the Montreal Protocol on Substances that Deplete the Ozone Layer of 1987. Exemplifying an inherently adaptive science-based approach, the treaty has been amended five times to reflect an updated base of knowledge and data on causes and effects of ozone depletion.

JOURNAL	Atmospheric Deposition of Mercury	12/01/2007

KNIGHTES, C. D., M. Meaburn, AND R. ARAUJO. Atmospheric Deposition of Mercury. EM: AIR AND WASTE MANAGEMENT ASSOCIATIONS MAGAZINE FOR ENVIRONMENTAL MANAGERS. Air & Waste Management Association, Pittsburgh, PA, 26-30, (2007).
Abstract:	With the advent of the industrial era, the amount of mercury entering the global environment increased dramatically. Releases of mercury in its elemental form from gold mines and chlor-alkali plants, as sulfides such as mercaptans and agricultural chemicals, and as volatile emissions from fossil fuel combustion became commonplace. Despite improvements in control methods, mercury pollution continues to be a serious environmental problem and poses a significant health risk to both humans and wildlife.

JOURNAL	Seeking More Effective Management of Freshwater Pollution	12/01/2007

MOHAMOUD, Y. M., P. Restrepo, C. C. WEST, AND M. J. Plodinec. Seeking More Effective Management of Freshwater Pollution. EM: AIR AND WASTE MANAGEMENT ASSOCIATIONS MAGAZINE FOR ENVIRONMENTAL MANAGERS. Air & Waste Management Association, Pittsburgh, PA, 33-35, (2007).
Abstract:	The atmosphere contains airborne pollutants such as mercury, nitrogen oxides, and sulfur oxides released from automobiles, factories, and power plants. Similarly, land surfaces such as croplands, feedlots, logged forests, construction sites, and urban land surfaces may be reservoirs of pollutants. The hydrologic cycle acts as the major driving force for the movement of these pollutants from these land surfaces - nutrients, sediments, and pathogens - to receiving water bodies. In this paper, we highlighted the interdependences between watershed disturbances particularly land use change and freshwater pollution. We also emphasized the need for more interactions between scientists and environmental managers.

JOURNAL	Standard Reporting Requirements for Biological Samples in Metabolomics Experiments: Environmental Context	09/20/2007

Morrison, N., D. Bearden, J. G. Bundy, T. W. COLLETTE, F. Currie, M. P. Davey, N. S. Haigh, D. Hancock, O. A. Jones, S. Rochfort, S. Sansone, D. Stys, Q. TENG, D. Field, AND M. R. Viant. Standard Reporting Requirements for Biological Samples in Metabolomics Experiments: Environmental Context. Metabolomics. Plenum Press, New York, NY, 3(3):203-210, (2007).
Abstract:	Metabolomic technologies are increasingly being applied to study biological questions in a range of different settings from clinical through to environmental. As with other high-throughput technologies, such as those used in transcriptomics and proteomics, metabolomics continues to generate large volumes of complex data that necessitates computational management. Making sense of this wealth of information also requires access to sufficiently detailed and well annotated meta-data. Here we provide standard reporting requirements for describing biological samples, taken from an environmental context and involved in metabolomic experiments. It is our intention that these reporting requirements should guide and support the standardised annotation, dissemination and interpretation of environmental metabolomics meta-data.

JOURNAL	Influence of Dissolved Organic Matter and Fe (II) on the Abiotic Reduction of Pentachloronitrobenzene	11/01/2007

Hakala, J. A., Y. P. Chin, AND E. J. WEBER. Influence of Dissolved Organic Matter and Fe (II) on the Abiotic Reduction of Pentachloronitrobenzene. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 41(21):7337-7342, (2007).
Abstract:	Nitroaromatic pesticides (NAPs) are hydrophobic contaminants that can accumulate in sediments by the deposition of suspended solids from surface waters. Fe(II) and dissolved organic matter (DOM), present in suboxic and anoxic zones of freshwater sediments, can transform NAPs in natural systems. We studied the reduction of pentachloronitrobenzene (PCNB) to pentachloroaniline (PCA) in controlled studies using Fe(II) and surface water DOM isolates from Pony Lake, Antarctica, and Suwannee River, GA.

PAPER IN NON-EPA PROCEEDINGS	Comparison of the Temporal Variability of Enterococcal Clusters in Impacted Streams Using a Multiplex Polymerase Chain Reaction Procedure	03/27/2007

MOLINA, M., M. J. CYTERSKI, J. MAIMES, J. FISHER, AND B. JOHNSON. Comparison of the Temporal Variability of Enterococcal Clusters in Impacted Streams Using a Multiplex Polymerase Chain Reaction Procedure. In Proceedings, 2007 Georgia Water Resources Conference, Athens, GA, March 27 - 29, 2007. Georgia Institute of Technology, Atlanta, GA, 1-4, (2007).
Abstract:	Understanding how fecal indicator bacteria and/or fecal indicator genotypes vary over time is important to determine the sources of fecal contamination. Enterococcus is one of the two indicators recommended by the EPA to monitor freshwaters for fecal contamination. Along with Escherichia coli, it has been used by a number of researchers to infer sources of fecal contamination, an area identified as microbial source tracking (MST). Our objective in this study was to identify changes in the seasonal distribution of enterococcal populations in streams directly impacted by cattle farming. The sites under study are located in Madison County, Ga., in farms where cows have unrestricted access to first order streams. Enterococci were counted and isolated monthly from water samples using membrane filtration. The isolates were identified using a multiplex PCR procedure. From a total of nine species identified in stream samples, only the most frequently observed species (E. faecalis, E. casseliflavus, E. flavescens, E. faecium and E. hirae) were used to develop groupings of enterococcal populations via cluster analysis. This analysis revealed that E. casseliflavus and E. faecalis dominated the enterococcal community during spring and fall, respectively. The cluster dominated by E. faecium seemed to increase during winter. This study indicates that enterococcal communities exhibit seasonal variability; and suggests that cluster analysis is a robust approach to identify this variability. In conclusion, to determine the true impact of certain farming operations on stream water quality using enterococcal species as indicators, it is important to consider the temporal variability of key enterococcal communities.

PAPER IN NON-EPA PROCEEDINGS	Using Long-Term Chemical and Biological Indicators to Assess Stream Health in the Upper Oconee River Watershed	03/27/2007

KOMINOSKI, J. S., B. J. MATTSSON, B. RASHLEIGH, AND S. L. EGGERT. Using Long-Term Chemical and Biological Indicators to Assess Stream Health in the Upper Oconee River Watershed. In Proceedings, 2007 Georgia Water Resources Conference, Athens, GA, March 27 - 29, 2007. Georgia Institute of Technology, Atlanta, GA, 1-4, (2007).
Abstract:	Macroinvertebrates are commonly used as biological indicators of stream habitat and water quality. Chemical variables, such as dissolved oxygen (DO), specific conductance (SC), and turbidity are used to measure stream water quality. Many aquatic macroinvertebrates are sensitive to changes in water chemistry, and streams with degraded water quality are often characterized by low macroinvertebrate diversity. Chemical (DO, SC, turbidity) and biological (macroinvertebrates) data from multiple tributaries of the North and Middle Oconee Rivers in Clarke County, Georgia, USA were collected seasonally from 2000-2006. Macroinvertebrates were identified, and communities were scored using the Georgia Adopt-A-Stream biotic index. Significant differences in biotic index scores were identified across sites and time using a two-way ANOVA. A general linear model relating chemical variables to biological score was more parsimonious than a model without chemical variables. These relationships varied by sample site, but they were consistent across seasons and years. Macroinvertebrate communities became degraded with increasing specific conductance, but associations with the other chemical variables were unclear. Results suggest the importance of using long-term chemical and biological indices in assessing stream health.

PAPER IN NON-EPA PROCEEDINGS	Concentrations and Estimated Loads of Nitrogen Contributed By Two Adjacent Wetland Streams With Different Flow-Source Terms in Watkinsville, Ga	03/27/2007

SCHROER, K., D. M. ENDALE, C. T. STEVENS, J. W. WASHINGTON, AND V. NZENGUNG. Concentrations and Estimated Loads of Nitrogen Contributed By Two Adjacent Wetland Streams With Different Flow-Source Terms in Watkinsville, Ga. In Proceedings, Georgia Water Resources Conference, Athens, GA, March 27 - 29, 2007. Georgia Institute of Technology, Atlanta, GA, 1-4, (2007).
Abstract:	Inorganic, fixed nitrogen from agricultural settings often is introduced to first-order streams via surface runoff and shallow ground-water flow. Best management practices for limiting the flux of fixed N to surface waters often include buffers such as wetlands. However, the efficacy of wetlands to immobilize or reduce nitrate depends on several interacting local conditions that are not well understood. Two adjacent streams (14 m apart at source) draining a wetland depression have partly different flow-source terms. One has a flowing spring at its head-cut, and is protected by surface runoff by a man-made berm. The other accepts run-off from the upland pasture and does not have a conspicuous spring. The lower discharge, and higher organic substrate, residence times and water/sediment contact all apparently contribute to the lower nitrogen flux out of the runoff stream.

PAPER IN NON-EPA PROCEEDINGS	Trend Analysis of Water Quality Monitoring Data for Cobb County, Georgia	03/27/2007

RASHLEIGH, B. AND R. BOURNE. Trend Analysis of Water Quality Monitoring Data for Cobb County, Georgia. In Proceedings, 2007 Georgia Water Resources Conference, Athens, GA, March 27 - 29, 2007. Georgia Institute of Technology, Atlanta, GA, 1-4, (2007).
Abstract:	The Cobb County Water Protection Division Water Quality Laboratory has conducted quarterly chemical monitoring from 1995-2005. Here we analyze these data for temporal trends at 45 sites in 10 Piedmont streams in the Chattahoochee and Etowah river basins. The strongest overall trends were increases in conductivity, chlorides, TKN, and NOx and decreases in Copper and Zinc. Some sites showed a decrease in turbidity, TSS, and percent dissolved oxygen saturation. To the extent that changes in water quality have resulted from increasing urbanization and development in the watershed, the best indicators of land use change in Cobb County may be conductivity and TKN. This dataset provides a unique opportunity to examine water quality trends for a rapidly developing region of Georgia.

PAPER IN NON-EPA PROCEEDINGS	Solid-Phase Extraction of 35 DBPs With Analysis By Gc/Ecd and Gc/MS	11/04/2007

CHINN, R., T. LEE, S. KRASNER, M. DALE, S. D. RICHARDSON, J. G. PRESSMAN, T. F. SPETH, R. J. MILTNER, AND J. E. SIMMONS. Solid-Phase Extraction of 35 DBPs With Analysis By Gc/Ecd and Gc/MS. In Proceedings, 2007 Water Quality Technology Conference, Charlotte, NC, November 04 - 08, 2007. American Water Works Association, Denver, CO, 1-20, (2007).
Abstract:	An analytical method for 35 disinfection by-products (DBPs) was developed for a U.S. Environmental Protection Agency (EPA) health effects study. A toxicological evaluation was conducted on drinking water that was "scaled-up" using reverse osmosis (RO) by concentrating the total organic carbon (TOC) from a treated surface water by ~130-fold, replacing bromide lost in the concentration process, and subjecting the concentrate to chlorine disinfection scaled up by the increased TOC content. This concentrated water presented analytical challenges, which were resolved by merging two methods, providing excellent quality control data while increasing the efficiency of the analysis and offering confirmation data for 19 of the target analytes. An automated solid phase extraction procedure was used for all of the sample preparation and the liquid-liquid extraction (LLE) method was eliminated. The sample extract was divided into two separate volumes for analysis by two different instruments. The previously used LLE method offered better extraction recoveries; however other drawbacks of the LLE method resulted in the selection and use of the solid phase extraction method. Quality control data was compared between the two instrumental methods and were found to be similar. Disinfection by-product degradation was shown to occur in two ways: base-catalyzed hydrolysis in water and thermal loss during heated injections on the gas chromatograph. Analytical conditions were chosen to minimize these problems.

PRESENTATION	Emerging Environmental Contaminants: Achievements and Challenges With Mass Spectrometry	02/26/2007

RICHARDSON, S. D. Emerging Environmental Contaminants: Achievements and Challenges With Mass Spectrometry. Presented at 58th Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy, Chicago, IL, February 25 - March 02, 2007.
Abstract:	Much has been achieved in the way of environmental protection over the last 30 years. However, as we learn more, new concerns arise. This presentation will discuss emerging contaminants that the U.S. Environmental Protection Agency (EPA) and other agencies are currently concerned about and will discuss the achievements being made with mass spectrometry, along with the challenges in measuring these contaminants. Included in this group of emerging contaminants are perfluorooctanoic acid (PFOA) and other perfluorinated compounds, pharmaceuticals, pesticide degradation/reaction products, and polybrominated diphenyl ethers (PBDEs); emerging drinking water pollutants, such as perchlorate, organotins, and algal toxins; and new drinking water disinfection by-products (DBPs), such as nitrosodimethylamine (NDMA), iodo-acids, iodo-trihalomethanes, and bromonitromethanes. Many of these contaminants have been proposed for consideration under the Unregulated Contaminants Monitoring Rule, which requires EPA to select five or more contaminants every five years to consider for regulation. Also, several of these are listed or being considered for EPA's Contaminant Candidate List (CCL), which identifies drinking water contaminants that might be regulated by EPA at a future date. Analytical methods are available for many of the proposed contaminants; however, several contaminants do not have rugged, reliable methods. The status and issues with these chemical contaminants will be discussed.

PRESENTATION	Using Long-Term Chemical and Biological Indicators to Assess Stream Health in the Upper Oconee River Watershed	03/27/2007

KOMINOSKI, J. S., B. J. MATTSON, B. RASHLEIGH, AND S. L. EGGERT. Using Long-Term Chemical and Biological Indicators to Assess Stream Health in the Upper Oconee River Watershed. Presented at Georgia Water Resources Conference, Athens, GA, March 27 - 29, 2007.
Abstract:	Macroinvertebrates are commonly used as biological indicators of stream water and habitat quality. Sediment is a common pollutant in streams, and high levels of sediment are linked with decreased dissolved oxygen (DO) in stream ecosystems. Many aquatic macroinvertebrates are sensitive to changes in DO, and streams containing low levels of DO are often characterized with low macroinvertebrate diversity. Stream-dependent birds have been shown to be effective indicators of stream quality, and few studies have compared the relationship between stream macroinvertebrate and riparian bird communities. Chemical (turbidity and DO) and biological (stream macroinvertebrates) data from multiple tributaries of the North and Middle Oconee Rivers in Clarke County, Georgia, USA were collected seasonally from 2000-2006. Riparian bird data was collected Settable solids were measured as a surrogate for turbidity (NTU) using the Imhoff cone method, and DO (mg L-1) was calculated using Sodium Thiosulfate titration. Macroinvertebrates were identified and community assemblages were scored using Georgia Adopt-A-Stream biological sampling and identification protocols. Riparian bird species diversity was measured using visual surveys. Pairwise comparisons of chemical and biological parameters were analyzed using simple regression. Relationships between DO, turbidity, and macroinvertebrate score were variable. There was a positive relationship between macroinvertebrate score and riparian bird assemblage. Results suggest the importance of using multiple chemical and biological indices in assessing stream health.

PRESENTATION	Trend Analysis of Water Quality Monitoring Data for Cobb County, Georgia	03/27/2007

BOURNE, R. AND B. RASHLEIGH. Trend Analysis of Water Quality Monitoring Data for Cobb County, Georgia. Presented at Georgia Water Resources Conference, Athens, GA, March 27 - 29, 2007.
Abstract:	The Cobb County Water Protection Division Water Quality Laboratory has conducted quarterly chemical monitoring from 1995-2005. Here we analyze these data for temporal trends in 20 Piedmont streams in the Chattahoochee and Etowah river basins. We found trends through time at most sites for most parameters; overall, temperature increased slightly, percent dissolved oxygen saturation decreased, and conductivity increased. To the extent that the changes in water quality have resulted from land use change and increasing urbanization and development in the watershed, the best indicators of land use change in Cobb County may be oxygen saturation and conductivity. This dataset provides a unique opportunity to examine water quality trends for a rapidly developing region of Georgia.

PRESENTATION	Application of the Hspf Model to the South Fork of the Broad River Watershed in Northeastern Georgia	03/27/2007

MOHAMOUD, Y. M. AND L. M. PRIETO. Application of the Hspf Model to the South Fork of the Broad River Watershed in Northeastern Georgia. Presented at Georgia Water Resources Conference, Athens, GA, March 27 - 29, 2007.
Abstract:	The Hydrological Simulation Program-Fortran (HSPF) is a comprehensive watershed model which simulates hydrology and water quality at user-specified temporal and spatial scales. Well-established model calibration and validation procedures are followed when adjusting model parameter values. In general, parameter values that result in good agreement between simulated and observed streamflow and water quality are retained. Final parameter selection often depends on the accuracy of the model input data, particularly the temporal and spatial resolution of precipitation data. This study evaluates how calibrated model parameter values respond to changes in temporal and spatial resolution of precipitation data over a watershed. Based on sensitivity of specific parameters to the resolution of spatial and temporal scale of precipitation data, this study demonstrates how HSPF parameter values shift to compensate for errors in precipitation resolution. In addition, it establishes typical HSPF model parameter values for Piedmont watersheds in Northeastern Georgia.

PRESENTATION	Concentrations and Estimated Loads of Nitrogen Contributed By Two Adjacent Wetland Streams With Different Flow-Source Terms in Watkinsville, Georgia	03/27/2007

SCHROER, K., D. M. ENDALE, C. T. STEVENS, J. W. WASHINGTON, AND V. NZENGUNG. Concentrations and Estimated Loads of Nitrogen Contributed By Two Adjacent Wetland Streams With Different Flow-Source Terms in Watkinsville, Georgia. Presented at Georgia Water Resources Conference, Athens, GA, March 27 - 29, 2007.
Abstract:	Inorganic, fixed nitrogen from agricultural settings often is introduced to first-order streams via surface runoff and shallow ground-water flow. Best management practices for limiting the flux of fixed N to surface waters often include buffers such as wetlands. However, the efficacy of wetlands to immobilize or reduce nitrate depends on several interacting local conditions that are not well understood. At the USDA-ARS, J. Phil Campbell Sr. National Resource Conservation Center in Watkinsville, Georgia, two adjacent streams (14m apart at head-cut) in a wetland depression provide drainage for an upland pasture for beef cattle. One of the streams is protected from surface run-off by a man-made berm and has a flowing spring at its head-cut. The other stream is not protected from runoff and does not have a conspicuous spring. Due to the different flow-source terms, chemical-species distribution is very different in the two adjacent stream channels. This research is part of a larger study in which in-stream processes are being evaluated to account for N loss along each channel. However, quantifying the individual nitrogen species and total N loadings contributed by each of the two channels will shed light on the importance of specific wetland hydrological and geochemical conditions to delivery of fixed N from agricultural settings to receiving waters.

PRESENTATION	Designing Pesticide Metabolic Pathway/Degradate Databases for Registrant Submitted Health Effects/Ecological Effects Data	02/07/2007

KOLANCZYK, R. C., W. J. JONES, O. MEKENYAN, A. PROTZEL, G. DANNAN, S. ABEL, AND P. K. SCHMIEDER. Designing Pesticide Metabolic Pathway/Degradate Databases for Registrant Submitted Health Effects/Ecological Effects Data. Presented at BOSC SP2 Review, Research Triangle Park, NC, February 07 - 09, 2007.
Abstract:	OPPTS requires information on the toxic effects of pesticide metabolites as well as the parent chemical. Currently, OPP receives metabolic maps with registrant study data submissions, but there is no efficient way to access previously submitted maps on similar chemicals to help with assessment of new chemicals. Information from past studies is used by risk assessors to assess the likelihood that all potentially toxic metabolites have been considered. More efficient use of existing data is needed to meet the challenge of resource limitations and aggressive assessment deadlines. Additionally, without access to this data, it is difficult to identify similarities in chemical metabolism and for researchers to formulate and test hypotheses for the types of chemicals that are of highest concern to EPA.

PRESENTATION	Simulating Metabolism to Enhance Effects Modeling	02/07/2007

JONES, W. J., R. C. KOLANCZYK, O. MEKENYAN, A. PROTZEL, AND P. K. SCHMIEDER. Simulating Metabolism to Enhance Effects Modeling. Presented at BOSC SP2 Review, Research Triangle Park, NC, February 07 - 09, 2007.
Abstract:	A major uncertainty that has long been recognized in evaluating chemical toxicity is accounting for metabolic activation of chemicals resulting in increased toxicity. The proposed research will develop a capability for forecasting the metabolism of xenobiotic chemicals of EPA interest and to allow prediction of the most likely chemical metabolites to be formed. The information is interfaced with toxic effect models allowing prediction of parent chemical toxic potential and of chemical metabolites of equal or greater toxicity than the parent chemical. These predictions will enable reasonable decisions to be made as to whether or not empirical studies are required to further refine a risk assessment, and will allow OPPTS to move toward a new assessment paradigm that targets specific effects data needs, for specific chemicals and exposures, that are essential to assess and manage risks appropriately.

PRESENTATION	Organophosphate Pesticide Degradation Pathways During Drinking Water Treatment	06/17/2007

DUIRK, S. E., L. M. DESETTO, AND T. W. COLLETTE. Organophosphate Pesticide Degradation Pathways During Drinking Water Treatment. Presented at Micropol and Ecohazard 2007 5th IWA Specialised Conference on Assessment and Control of Micropollutants/Hazardous Substances in Water, Frankfurt, GERMANY, June 17 - 20, 2007.
Abstract:	Free chlorine has been found to react with organophosphate (OP) pesticides resulting in the more toxic oxon products. We will discuss OP pesticide degradation pathways and modeling in the presence of chlorine and chloramines, as well as present a relationship between structure and reactivity with each disinfectant. These structure activity relationships and models will aid regulators in determining the risk associated with drinking OP pesticide contaminated potable water.

PRESENTATION	The Impact of Cdom Photobleaching on UV Attenuation Near Coral Reefs in the Florida Keys	02/04/2007

ZEPP, R. G., G. SHANK, AND C. ROSENFELD. The Impact of Cdom Photobleaching on UV Attenuation Near Coral Reefs in the Florida Keys. Presented at ASLO 2007 Aquatic Sciences Meeting, Santa Fe, NM, February 04 - 09, 2007.
Abstract:	We have investigated how the loss of chromophoric dissolved organic matter (CDOM) in the water column due to photobleaching allows for increased penetration of UV radiation near coral reefs in the Florida Keys. Extended exposure to UV may contribute to coral bleaching episodes. CDOM serves as the primary control on UV exposure of corals in this region because it strongly absorbs UV radiation, especially damaging UVB wavelengths. An important fraction of the CDOM pool in Florida Keys coastal waters is transported from Florida Bay, but local sources including seagrasses, mangroves, and Sargassum colonies may also be substantial. CDOM samples collected along transects near the reefs and from mangrove leaf and Sargassum incubation experiments were exposed to simulated solar radiation for up to 96 hours. Calculated photobleaching rates (k305) of CDOM produced by mangrove leaf litter and Sargassum colonies (approx. 0.02 hr (-1)) were an order of magnitude greater than rates measured for the water column samples (0.002 hr (-1)). However, our experiments indicate that photobleaching of CDOM in natural waters near the reefs can still be substantial during summer months and may allow UVB levels at 4 m depth (typical depth of fringing reefs) to increase by as much as 20%. Corals located in shallower waters (2 m) along the reef line may experience up to a 40% increase in UVB exposure due to loss of CDOM.

PRESENTATION	Factors Influencing Light-Induced Mortality of Enterococci in Sediment Suspensions	02/05/2007

ZEPP, R. G. AND R. JONES. Factors Influencing Light-Induced Mortality of Enterococci in Sediment Suspensions. Presented at ASLO 2007 Aquatic Sciences Meeting, Santa Fe, NM, February 04 - 09, 2007.
Abstract:	Contamination of recreational waters by pathogenic microorganisms occurs through complex, poorly understood interactions involving variable microbial sources, hydrodynamic transport, arid microbial fate processes. Fecal indicator bacteria such as enterococci have been used to assess such contamination. Here we report laboratory studies of the sorption and light-induced mortality of enterococci in suspensions of sediments from streams and ponds in the Piedmont region of the southeastern United States. The studies indicated that enterococci are strongly associated with the suspended and bottom sediments of these systems. Size fractionation studies indicated that the bacteria were predominantly partitioned to clay-sized sediments that are readily suspended in the water column by currents or wind action. Direct exposure of the sorbed bacteria to solar radiation resulted in rapid mortality of the enterococci with half-lives of a few minutes. In the dark, mortality half-lives were much longer, on the order of several days. Other studies indicated that the UV component of the solar radiation was mainly responsible for inducing mortality.

PRESENTATION	Nowcasting and Forecasting Beach Bacteria Concentrations Using EPA Virtual Beach Software	02/04/2007

FRICK, W. E. AND Z. GE. Nowcasting and Forecasting Beach Bacteria Concentrations Using EPA Virtual Beach Software. Presented at ASLO 2007 Aquatic Sciences Meeting, Santa Fe, NM, February 04 - 09, 2007.
Abstract:	Evidence shows that traditional persistence-based beach closure decision making is inadequate, beaches are closed when they could be open and kept open when they should be closed. Intense interest is now focused on efforts to nowcast beach conditions using surrogate variables, such as turbidity, temperature, rainfall, and other variables. Contributing to the effort to alert to public, EPA developed the Virtual Beach software program to help users develop beach bacteria concentration models. Similar approaches have been used to develop beach advisories. In tests conducted during the summer of 2006, the authors found that the multi-variable linear regression statistical approach could be extended to forecasting using publicly available weather and water forecasts. Using data from the 2006 Huntington Beach, Lake Erie advisory project, 24 and 48 hour forecasts were found to be about as accurate as nowcasting results. It is hypothesized that the greater precision of some forecasts compensate for the decreasing accuracy of weather and water forecasts. Further forecasting tests of Virtual Beach are planned for the 2007 bathing season.

PRESENTATION	Methodological Approach for Measuring Priority DBPs in Reverse Osmosis Concentrated Drinking Water	03/26/2007

BODIN, N., H. S. WEINBERG, S. W. KRASNER, S. D. RICHARDSON, J. G. PRESSMAN, T. F. SPETH, R. J. MILTNER, AND J. E. SIMMONS. Methodological Approach for Measuring Priority DBPs in Reverse Osmosis Concentrated Drinking Water. Presented at American Chemical Society National Meeting, Chicago, IL, March 25 - 29, 2007.
Abstract:	Many disinfection by-products (DBPs) are formed when drinking water is chlorinated, but only a few are routinely measured or regulated. Various studies have revealed a plethora of DBPs for which sensitive and quantitative analytical methods have always been a major limiting factor in developing an occurrence database. In an effort to extend our grasp of the potential health implications of current disinfection practices, approximately 500 of these DBPs that had been reported in the literature were prioritized according to predicted cancer effects and subsequently 50 of these were identified as high priority for a large-scale occurrence study across the U.S.A. Although many new sensitive analytical methods were developed for these new DBPs, some of them were found at levels close to or below their detection limits. Moreover, most of the previous toxicological testing for DBPs had been carried out on a single chemical-by-chemical basis, which could not account for the nature of a complex drinking water mixture nor explain the adverse health effects observed in some epidemiologic studies. Consequently, a new study was evolved that addressed these two weaknesses and provided for comprehensive chemical determination and toxicological evaluation of environmentally realistic complex mixtures of DBPs. In the present part of this large multi-disciplinary effort, drinking water was scaled-up by concentrating the total organic carbon (TOC) from a treated surface water and subjecting the concentrate to chlorination, using similar chlorine dose to TOC and bromide to TOC ratios as would be used or found in conventional treatment. Higher levels of all DBPs would be produced that could be detectable using currently available methods and a battery of toxicological assays could then focus on adverse health effects and correlate these to the levels and mixture of DBPs. This paper focuses on adaptation of methods used for quantitation of over 50 priority DBPs from drinking water to chlorinated surface water concentrates.

PRESENTATION	Chlorinated Vs. Chloraminated Drinking Water: Toxicity-Based Identification of Disinfection By-Products Using Esi-MS and Esi-MS/MS	03/26/2007

RICHARDSON, S. D., F. G. CRUMLEY, M. J. PLEWA, E. D. WAGNER, T. H. MIZE, P. ANGEL, R. ORLANDO, L. WILLIAMSON, AND M. G. BARTLETT. Chlorinated Vs. Chloraminated Drinking Water: Toxicity-Based Identification of Disinfection By-Products Using Esi-MS and Esi-MS/MS. Presented at American Chemical Society National Meeting, Chicago, IL, March 25 - 29, 2007.
Abstract:	Drinking water disinfection by-products (DBPs) are of concern because some epidemiologic studies have shown that some DBPs are associated with cancer or adverse reproductive/developmental effects in human populations, and other studies have shown that certain DBPs cause similar health effects in laboratory animals. As a result, the U.S. EPA has regulated several DBPs. However, more than 500 DBPs have been reported in drinking water for which little or no occurrence and health data exist. The goal of this research is to use a bio-assay 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 and chloramines as disinfectants, and this drinking water was fractionated initially according to molecular size (through the use of ultrafiltration membranes). Mammalian cell genotoxicity and cytotoxicity assays were used to determine the toxicity of the fractions, and electrospray ionization (ESI)-mass spectrometry (MS) and ESI-MS/MS were used to obtain structural information on the DBPs in those fractions.

PRESENTATION	Meeting in New Zealand: Emerging Environmental Contaminants and Current Issues	02/09/2007

RICHARDSON, S. D. Meeting in New Zealand: Emerging Environmental Contaminants and Current Issues. Presented at EnviroAnalysis Conference, Wellington, NEW ZEALAND, February 07 - 10, 2007.
Abstract:	Much has been achieved in the way of environmental protection over the last 30 years. However, as we learn more, new concerns arise (including potential adverse health effects, bioaccumulation, and widespread distribution). This presentation will discuss emerging environmental contaminants that the U.S. EPA and other agencies are currently concerned about. Emerging contaminants include drinking water disinfection by-products (DBPs), pharmaceuticals, perfluorooctanoic acid (PFOA), polybrominated diphenyl ether (PBDE) flame retardants, 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. Concerns with PFOA and PBDEs include widespread global distribution in the blood of the general population and in wildlife, as well as potential health effects, including cancer and developmental toxicity. Pharmaceuticals are of concern due to antibiotic resistance and potential endocrine disrupting effects. Some of the emerging contaminants (e.g., nitrosamines, PBDE flame retardants, and pesticide degradation products) are currently listed on the proposed Unregulated Contaminants Monitoring Rule (UCMR2), which requires EPA to select five or more contaminants every five years to consider for regulation. Other emerging contaminants are listed on the Contaminant Candidate List (CCL), which identifies drinking water contaminants that might be regulated by EPA at a future date, and other emerging contaminants are currently under consideration for the UCMR and the 3rd CCL. The status and health/environmental issues with these emerging environmental contaminants will be discussed, as well as analytical methods used to measure them.

PRESENTATION	Data for Environmental Modeling (D4em)	05/22/2007

WOLFE, K. L., R. S. PARMAR, G. F. LANIAK, D. P. AMES, M. H. GRAY, A. PARKS, AND L. WILSON. Data for Environmental Modeling (D4em). Presented at International Symposium on Environmental Software Systems, Prague, CZECH REPUBLIC, May 22 - 25, 2007.
Abstract:	Data is a basic requirement for most modeling applications. Collecting data is expensive and time consuming. High speed internet connections and growing databases of online environmental data go a long way to overcoming issues of data scarcity. 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. This project demonstrates the development of a comprehensive set of open source software tools that bridge these obstacles by allowing a model developer to programmatically populate model input datasets with environmental data available from distributed data sources. Data management and geoprocessing components allow for complex data transformations. Geoprocessing operations are implemented through linkages with open source GIS software. The components also handle metadata and data caching. While this project was initially undertaken to meet the data requirements for two US Environmental Protection Agency (USEPA) modeling systems, i.e. 3MRA (Multimedia, Multi-pathway, Multi-receptor Risk Assessment) and the BASINS (Better Assessment Science Integrating Point and Non-point Sources), its component-based architecture allows it to be integrated into other modeling applications. The components are written in Microsoft .Net languages ¿ C# and Visual Basic .Net. Current data sources include: EPA¿s STORET data, US Geological Survey (USGS) Terraserver maps and photos, USGS National Water Information System (NWIS) data and the multi agency National Land Cover Dataset.

PRESENTATION	The Science of Remediation, Abatement, and Decommissioning of Catastrophic (and Lesser) Events	02/15/2007

KITCHENS, J. The Science of Remediation, Abatement, and Decommissioning of Catastrophic (and Lesser) Events. Presented at Georgia Science Teacher's Association Conference, Athens, GA, February 15, 2007.
Abstract:	This is a brief overview of some of the activities commonly involved in remediation, abatement, and decommissioning of areas affected by significant events whether natural or man-made. Some examples from the EPA's post-Katrina and anthrax responses are used to demonstrate the scientific and technical nature of activities.

PRESENTATION	Introduction to a Combined Multiple Linear Regression and Arma Modeling Approach for Beach Bacteria Prediction	05/29/2007

GE, Z. AND W. E. FRICK. Introduction to a Combined Multiple Linear Regression and Arma Modeling Approach for Beach Bacteria Prediction. Presented at IAGLR's 50th Annual Conference on Great Lakes Research, University Park, PA, May 28 - June 01, 2007.
Abstract:	Due to the complexity of the processes contributing to beach bacteria concentrations, many researchers rely on statistical modeling, among which multiple linear regression (MLR) modeling is most widely used. Despite its ease of use and interpretation, there may be time dependences in the observations that cannot be explained by the MLR model, so that the residuals are not as random as they are assumed to be. In this case, an ARMA (auto-regressive moving average) model can be used to extract the possible deterministic time patterns from the MLR residuals. The ARMA-modeled deterministic part of the residual is then added to the MLR predictions as an adjustment, and the variance of the prediction errors can be considerably reduced. The whole modeling process is demonstrated with actual data from Huntington Beach, Ohio, in 2000-2004. Results show that the predictive capacity of the initial MLR model is significantly improved by making use of the supplemental ARMA technique. Supplemental ARMA modeling is an independent step that does not otherwise affect the existing MLR models, another attractive feature of this approach.

PRESENTATION	Ecosystem Services and Beyond: Integration of Ecosystem Science and Multimedia Exposure Modeling for Environmental Protection	05/23/2007

JOHNSTON, J. M., G. F. LANIAK, AND R. B. AMBROSE. Ecosystem Services and Beyond: Integration of Ecosystem Science and Multimedia Exposure Modeling for Environmental Protection. Presented at EcoSummit 2007, Beijing, CHINA, May 22 - 27, 2007.
Abstract:	Decision-making for ecosystem protection and resource management requires an integrative science and technology applied with a sufficiently comprehensive systems approach. Single media (e.g., air, soil and water) approaches that evaluate aspects of an ecosystem in a stressor-by-stressor fashion, or those that do not include human endpoints and values are incomplete and as a result of limited value. Valued ecosystem endpoints and services and the interactions of these components are described in several examples, with the knowledge that many processes and model-dependent inputs (e.g, process rates, initial conditions, and parameter estimates) will be underdetermined. A sufficient scientific assessment includes both an explicit treatment of ecosystem complexity, grounded in ecological principles, as well as scientific uncertainty. We describe a methodology that addresses problem statements across multiple spatial and temporal scales, with a support technology that can address the needs of a range of decision makers. The modeling framework serves as the infrastructure for data and model management, uncertainty and sensitivity analysis. Ecosystem services are illustrated with the example of provisioning of fisheries resources, and sustainability is defined operationally in a human-influenced system in the Mid-Atlantic Highlands (USA). Additional examples include nutrient management to mitigate eutrophication in agro-ecosystems, as well as the extension of the framework to the regulation of contaminants of emerging concern in managed systems.

PRESENTATION	Metabolomic Studies of Endocrine Disruption in Small Fish Models	04/23/2007

TENG, Q., D. R. EKMAN, T. W. COLLETTE, G. T. ANKLEY, K. M. JENSEN, M. D. KAHL, AND D. L. VILLENEUVE. Metabolomic Studies of Endocrine Disruption in Small Fish Models. Presented at 48th ENC Conference, Daytona, FL, April 22 - 27, 2007.
Abstract:	Metabolomics is now being widely used to obtain complementary information to genomic and proteomic studies. To better understand temporal, compensatory and dose responses to endocrine-disrupting chemicals (EDCs) within the hypothalamic-pituitary¬gonadal (HPG) axis, we have carried out NMR-based metabolomic studies on multiple tissues and biofluids of two important small fish models - fathead minnow and zebrafish. Reported here are the results of an exposure conducted using a model EDC at different dose levels and a number of time points during and after the exposure.

PRESENTATION	Nmr-Based Metabolomic Studies of Endocrine Disruption in Small Fish Models	05/20/2007

TENG, Q., D. R. EKMAN, T. W. COLLETTE, G. T. ANKLEY, K. M. JENSEN, M. D. KAHL, AND D. L. VILLENEUVE. Nmr-Based Metabolomic Studies of Endocrine Disruption in Small Fish Models. Presented at SETAC Europe 17th Annual Meeting, Porto, PORTUGAL, May 20 - 24, 2007.
Abstract:	Metabolomics is now being widely used to obtain complementary information to genomic and proteomic studies. Among the various approaches used in metabolomics, NMR spectroscopy is particularly powerful, in part because it is relatively non-selective, and is amenable to the study of biological samples in their native state whether in solution, cells or tissues. To better understand temporal, compensatory and dose responses to endocrine-disrupting chemicals (EDCs) within the hypothalamic-pituitary--gonadal (HPG) axis, we have carried out NMR-based metabolomics studies on multiple tissues and biofluids of two important small fish models - fathead minnow and zebrafish. Reported here are the results of an exposure conducted using a model EDC at different dose levels and a number of time points during and after the exposure. In addition, we will report the results of resonance assignment of metabolites in these tissues and biofluids that seem to be most related to exposure to important endocrine disrupting chemicals.

PRESENTATION	Design and Performance of a Xenobiotic Metabolism Database Manager for Metabolic Simulator Enhancement and Chemical Risk Analysis	05/21/2007

MEKENYAN, O., W. J. JONES, R. C. KOLANCZYK, AND P. K. SCHMIEDER. Design and Performance of a Xenobiotic Metabolism Database Manager for Metabolic Simulator Enhancement and Chemical Risk Analysis. Presented at SETAC Europe 17th Annual Meeting, Porto, PORTUGAL, May 20 - 24, 2007.
Abstract:	A major uncertainty that has long been recognized in evaluating chemical toxicity is accounting for metabolic activation of chemicals resulting in increased toxicity. In silico approaches to predict chemical metabolism and to subsequently screen and prioritize chemicals for risk assessments has been a goal of regulatory agencies for years. Research is underway to develop the capability for reliably forecasting the metabolism of xenobiotic chemicals (TIssue MEtabolism Simulator [TIMES] software) and to allow prediction of the most likely chemical metabolites to be formed. This information, when interfaced with toxic effect models, allows prediction of parent chemical toxic potential and of chemical metabolites of equal or greater toxicity than the parent chemical. The performance of a metabolic simulator can be enhanced for a particular toxic effect by collecting relevant measured chemical metabolism maps (e.g., from published literature and from specifically designed metabolism experiments). Newly acquired maps for relevant enzymatic transformations used to re-train the metabolism simulator improve simulator reliability. For example, chemicals forecasted to be metabolically transformed to estrogen receptor (ER) active forms are assessed in metabolically-competent liver slices from male fish that produce the metabolites and the subsequent effect, i.e., ER-mediated vitellogenin production. Metabolism data from these studies are used to improve metabolic simulations and to aid in the prioritization of chemicals for testing that have the potential to be bioactivated to ER active species. Metabolism data for training and improvement of the simulator are stored and accessed using the database manager software, MetaPath, capable of ubiquitous sub-structure search functions, depiction and comparison of metabolic maps, and providing access to metabolic maps and associated data. MetaPath software allows automated upload of metabolic maps and metadata from specifically-designed XML-coded Microsoft Word data templates. The metabolism database assembled in MetaPath may also be used as a stand-alone dataset by risk assessors to increase efficiency of metabolism data access allowing the risk assessor to perform searches for specific compounds and toxicophores and identify metabolism commonalities and differences across chemical classes, species, and dose-groups.

PRESENTATION	Nestedness in Riverine Freshwater Mussel Communities	06/04/2007

RASHLEIGH, B. Nestedness in Riverine Freshwater Mussel Communities. Presented at North American Benthological Society Meeting, Columbia, SC, June 03 - 07, 2007.
Abstract:	The pattern of nestedness, where species present at less diverse sites are subsets of species present in locations with higher species richness, 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 four 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. Nestedness was not related to differences in immigration probabilities. Site diversity increased in the downstream direction, giving some indication of structuring by differences in extinction among species. Mussel species distributions were not related to the number or distribution of their fish hosts. Nestedness may be due to a nestedness of fish hosts in terms of their 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.

PRESENTATION	Nowcasting and Forecasting Beach Bacteria Concentration Using the EPA Virtual Beach Software	05/29/2007

FRICK, W. E. AND Z. GE. Nowcasting and Forecasting Beach Bacteria Concentration Using the EPA Virtual Beach Software. Presented at IAGLR's 50th Annual Conference on Great Lakes Research, University Park, PA, May 28 - June 01, 2007.
Abstract:	Beaches are subject to closure when bacterial counts exceed water quality criteria. Many authorities base these decisions on sample counts, which typically require a day or more to analyze. Sometimes called the persistence model, because conditions are assumed to persist, experience shows that this approach often leads to poor decisions: beaches are often closed when they could be open and vice versa. Studies show mathematical models can outperform the persistence model. Many use multi-variable linear regression (MLR) that base predictions on explanatory variables, such as turbidity, temperature, rainfall, and other variables. Virtual Beach, software developed at EPA, does too. It has been used successfully to nowcast, the practice for using real-time variables to estimate existing bacteria concentrations. This work addresses the question, can weather and water forecasts be used to forecast beach conditions in advance? The answer is based on an analysis of 2006 Huntington Beach, Lake Erie beach data (by USGS, state, and local agencies), weather forecasts for nearby Cleveland-Hopkins international airport, and NOAA lake condition forecasts. A comparison of static and dynamic MLR models is also given.

PRESENTATION	Emerging DBPs and Current Issues	02/13/2007

RICHARDSON, S. D. Emerging DBPs and Current Issues. Presented at Water Care Company, Wellington, NEW ZEALAND, February 13, 2007.
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	The Transport of Oil in Water Bodies Subjected to Waves	02/01/2007

WEAVER, J. W. AND M. C. BOUFADEL. The Transport of Oil in Water Bodies Subjected to Waves. Presented at Dispersed Oil Research Forum, Red Bank, NJ, February 01 - 02, 2007.
Abstract:	This is a powerpoint presentation on the transport of oil in water bodies which was presented at the Dispersed Oil Research Forum, February 2007.

PRESENTATION	Modeling Fish and Shellfish Distributions in the Mobile Bay Estuary, USA	04/10/2007

RASHLEIGH, B., M. J. CYTERSKI, L. M. SMITH, AND J. NESTLERODE. Modeling Fish and Shellfish Distributions in the Mobile Bay Estuary, USA. Presented at Eighth Environmental Monitoring and Assessment Program (EMAP) Symposium, Washington, DC, April 10 - 11, 2007.
Abstract:	Estuaries in the Gulf of Mexico provide rich habitat for many fish and shellfish, including those that have been identified as economically and ecologically important. For the Mobile Bay estuary, we developed statistical models to relate distributions of individual species and species assemblages to two dozen water quality and habitat variables in a geo-referenced database. A hierarchical cluster analysis was performed on Mobile Bay fish and shellfish abundance data from 123 samples to identify groups of co-occurring species. Fifteen clusters were used subsequently in a discriminant analysis with water quality and habitat variables; a 65% success rate in classifying the fish assemblages was achieved. Next, habitat variables were used to develop predictive habitat models for individual species. Fish and shellfish responded most strongly to patterns of salinity, depth, substrate, and water chemistry. Results from this work could be used to guide restoration of degraded estuarine habitat, which is a key environmental goal of the National Estuary Program.

PRESENTATION	Gasoline Composition in the US (1976-2007)	02/22/2007

WEAVER, J. W. Gasoline Composition in the US (1976-2007). Presented at US EPA ORD Workshop: Modeling Contaminant Transport for LUST Sites, Denver, CO, February 21 - 22, 2007.
Abstract:	Slide presentation presented at the US EPA Workshop on Modeling Contaminant Transport for LUST Sites, February 21-22, 2007, in Denver, CO.

PRESENTATION	Meeting in Denver: Capabilities and Limitations of Contaminant Transport Models	02/22/2007

WEAVER, J. W. Meeting in Denver: Capabilities and Limitations of Contaminant Transport Models. Presented at US EPA ORD Workshop: Modeling Contaminant Transport for LUST Sites, Denver, CO, February 21 - 22, 2007.
Abstract:	Slide presentation presented at the US EPA Workshop on Modeling Contaminant Transport for LUST Sites, February 21-22, 2007, in Denver, CO.

PRESENTATION	Toxics in Our Rivers	02/17/2007

AMBROSE, R. B., C. D. KNIGHTES, AND B. RASHLEIGH. Toxics in Our Rivers. Presented at Georgia River Network Conference 2007 "Ensuring a Clean Water Legacy", Milledgeville, GA, February 17, 2007.
Abstract:	Slide presentation for the Georgia River Network Conference, February 21, 2007, Milledgeville, GA.

PRESENTATION	Meeting in Canada: Emerging Environmental Contaminants and Current Issues	04/10/2007

RICHARDSON, S. D. Meeting in Canada: Emerging Environmental Contaminants and Current Issues. Presented at 3rd Annual LC/MS and LC/MS/MS Applications in Environmental Analysis Conference, Guelph, ON, CANADA, April 10 - 11, 2007.
Abstract:	Much has been achieved in the way of environmental protection over the last 30 years. However, as we learn more, new concerns arise (including potential adverse health effects, bioaccumulation, and widespread distribution). This presentation will discuss emerging environmental contaminants that the U.S. EPA and other agencies are currently concerned about. Emerging contaminants include drinking water disinfection by-products (DBPs), pharmaceuticals, perfluorooctanoic acid (PFOA), polybrominated diphenyl ether (PBDE) flame retardants, pesticide degradation products, sunscreens/UV filters, and algal toxins. Emerging DBPs include iodo-acids, iodo-trihalomethanes, bromonitromethanes, haloamides, and nitrosamines (including nitrosodimethylamine, NOMA).

PRESENTATION	Integrating Models With Site Assessment Part One	02/22/2007

WEAVER, J. W. Integrating Models With Site Assessment Part One. Presented at US EPA ORD Workshop: Modeling Contaminant Transport for LUST Sites, Denver, CO, February 21 - 22, 2007.
Abstract:	Slide presentation presented at the US EPA Workshop on Modeling Contaminant Transport for LUST Sites, February 21-22, 2007, in Denver, CO.

PRESENTATION	Plume Formation Transport and Modeling	02/22/2007

WEAVER, J. W. Plume Formation Transport and Modeling. Presented at US EPA ORD Workshop: Modeling Contaminant Transport for LUST Sites, Denver, CO, February 21 - 22, 2007.
Abstract:	Slide presentation presented at the US EPA Workshop on Modeling Contaminant Transport for LUST Sites, February 21-22, 2007, in Denver, CO.

PRESENTATION	Meeting in Denver: Model Parameter Estimation	02/21/2007

WEAVER, J. W. Meeting in Denver: Model Parameter Estimation. Presented at US EPA ORD Workshop: Modeling Contaminant Transport for LUST Sites, Denver, CO, February 21 - 22, 2007.
Abstract:	Slide presentation presented at the US EPA Workshop on Modeling Contaminant Transport for LUST Sites, February 21-22, 2007, in Denver, CO.

PRESENTATION	Meeting in Denver: Modeling for Environmental Decision Making	02/21/2007

WEAVER, J. W. Meeting in Denver: Modeling for Environmental Decision Making. Presented at US EPA ORD Workshop: Modeling Contaminant Transport for LUST Sites, Denver, CO, February 21 - 22, 2007.
Abstract:	Slide presentation for the EPA Workshop on Modeling Contaminant Transport for LUST Sites, Denver, CO, February 21-22, 2007.

PRESENTATION	Gasoline Composition	03/05/2007

WEAVER, J. W. Gasoline Composition. Presented at 19th Annual National Tanks Conference, San Antonio, TX, March 05 - 07, 2007.
Abstract:	Slide presentation presented at the 19th Annual National Tanks Conference, San Antonio, TX, March 5-7, 2007.

PRESENTATION	Reductive Transformation of Organic Contaminants in Aquatic Systems	03/12/2007

COLON, D. Reductive Transformation of Organic Contaminants in Aquatic Systems. Presented at Seminar at the Medical Sciences Campus, University of Puerto Rico, San Juan, PUERTO RICO, March 12, 2007.
Abstract:	Slide presentation for seminar at the University of Puerto Rico, Medical Sciences Campus, March 12, 2007.

PRESENTATION	Comparative Distribution of Perfluorooctanoic Acid in Male, Female and Pregnant Mice Following Treatment With 8-2 Fluorotelomer Alcohol (Ftoh)	03/26/2007

HENDERSON, W. M. AND M. A. SMITH. Comparative Distribution of Perfluorooctanoic Acid in Male, Female and Pregnant Mice Following Treatment With 8-2 Fluorotelomer Alcohol (Ftoh). Presented at 46th Annual Meeting of the Society of Toxicology, Charlotte, NC, March 25 - 29, 2007.
Abstract:	The global occurrence of perfluorooctanoic acid (PFOA) in environmental and mammalian matrices has spurred regulatory interest in potential sources of this stable compound. 8-2 fluorotelomer alcohol, a primary compound used in polymer synthesis, is found ubiquitously in the environment and can undergo biotic and abiotic transformation to PFOA. An appropriate animal model is needed to fully elucidate the mechanisms of 8-2 FTOH metabolism and distribution of metabolites in mammals. The objective of this study was to compare the metabolism of 8-2 FTOH in male, female and pregnant mice.

PRESENTATION	Impacts of Regulation on U.S. Gasoline Composition	03/05/2007

WEAVER, J. W. AND L. R. EXUM. Impacts of Regulation on U.S. Gasoline Composition. Presented at 19th Annual National Tanks Conference, San Antonio, TX, March 05 - 07, 2007.
Abstract:	Poster presented at the 19th Annual National Tanks Conference, San Antonio, TX, March 5-7, 2007.

PRESENTATION	Environmental Impacts from Lead Scavengers in Avgas and Gasoline	03/05/2007

SPIDLE, D. L., J. W. WEAVER, S. BURTON, D. COLON, AND L. R. EXUM. Environmental Impacts from Lead Scavengers in Avgas and Gasoline. Presented at 19th Annual National Tanks Conference, San Antonio, TX, March 05 - 07, 2007.
Abstract:	Poster presented at the 19th Annual National Tanks Conference, San Antonio, TX, March 5-7, 2007.

PRESENTATION	Integrating Modeling Into Plume Diving Assessment	03/05/2007

WEAVER, J. W. AND V. GOROKHOVSKI. Integrating Modeling Into Plume Diving Assessment. Presented at 19th Annual National Tanks Conference, San Antonio, TX, March 05 - 07, 2007.
Abstract:	Poster presented at the 19th Annual National Tanks Conference, San Antonio, TX, March 5-7, 2007.

PRESENTATION	Meeting in Mexico: Nowcasting and Forecasting Beach Bacteria Concentration Using EPA's Virtual Beach Software	05/22/2007

FRICK, W. E. AND Z. GE. Meeting in Mexico: Nowcasting and Forecasting Beach Bacteria Concentration Using EPA's Virtual Beach Software. Presented at AGU 2007 Joint Assembly, Acapulco, MEXICO, May 22 - 25, 2007.
Abstract:	Beaches in the United States of (North) America are subject to closure when bacterial counts exceed water quality criteria. Many authorities base these decisions on water samples that typically require at least 18 hours to analyze. This persistence approach, or model, often leads to erroneous decisions due to the great variability in bacterial concentrations. Beaches are closed when they could be open and vice versa, their true status unknown until the next day. Studies show that mathematical models based on multi-variable linear regression (MLR) principles can produce better estimates, or nowcasts, using real-time explanatory variables, such as turbidity, cloud cover, and rainfall. To make such models generally available, the Environmental Protection Agency (EPA) is developing a program called Virtual Beach (VB). VB is public-domain software for developing site-specific predictive models. It features capabilities that make it possible with reasonable effort to develop, and compare the performance of, static and dynamic MLR models. The results of tests on 2006 Huntington Beach, Lake Erie beach data are presented. In addition to nowcasting, the work begins to address the question, can weather and water forecasts be used to forecast beach conditions in advance? A preliminary affirmative answer is provided based on an analysis of the Huntington Beach data, with weather forecasts for nearby Cleveland-Hopkins international airport, and NOAA lake condition forecasts. We encourage those engaged in beach monitoring and management to request VB, applying the nowcast and forecast models developed with it to their locations of interest.

PRESENTATION	Effects of Photochemical, Microbial and Sorption Processes on the Optical Properties and Degradation of Dissolved Organic Matter from Coastal Wetlands	04/03/2007

ZEPP, R. G., M. A. MORAN, W. SHELDON, E. BIERS, AND G. C. SHANK. Effects of Photochemical, Microbial and Sorption Processes on the Optical Properties and Degradation of Dissolved Organic Matter from Coastal Wetlands. Presented at 10th International Symposium on Wetland Biogeochemistry, Annapolis, MD, April 01 - 04, 2007.
Abstract:	The dissolved organic matter (DOM) exported from rivers and intertidal marshes to coastal oceans is rich in light-absorbing, fluorescent constituents, including humic substances and other polyphenolic moieties. Interactions between microbial and photochemical processes have important effects on the production and consumption of these chromophoric constituents. Nitrogen-containing compounds such as aminosugars and amino acids participate in the processes that produce the chromophores. Photoreactions alter decomposition rates of the DOM both through direct conversion to CO2, carbon monoxide and other trace gases and through DOM transformations to biologically labile photoproducts. These transformations are accompanied by changes in the absorption, fluorescence and isotopic composition of the DOM that contribute to observed changes in DOM properties in estuaries and coastal waters. Wavelength studies indicate that the ultraviolet and blue parts of solar irradiance induce the DOM photoreactions. Sorption of DOM to sediments also can affect DOM optical properties by selectively removing high-molecular-weight, light-absorbing humic substances.

PRESENTATION	Meeting in Charlotte: Solid-Phase Extraction of 35 DBPs With Analysis By Gc/Ecd and Gc/MS	11/06/2007

CHINN, R., T. LEE, S. KRASNER, M. DALE, S. D. RICHARDSON, J. G. PRESSMAN, T. F. SPETH, R. J. MILTNER, AND J. E. SIMMONS. Meeting in Charlotte: Solid-Phase Extraction of 35 DBPs With Analysis By Gc/Ecd and Gc/MS. Presented at 2007 Water Quality Technology Conference, Charlotte, NC, November 04 - 08, 2007.
Abstract:	An analytical method for 35 disinfection by-products (DBPs) was developed for a U.S. Environmental Protection Agency health effects study. A toxicological evaluation was conducted on drinking water that was scaled-up (using reverse osmosis) by concentrating the total organic carbon (TOC) from a treated surface water by ~130-fold, adjusting the bromide concentration to re-establish the natural TOC to bromide ratio, and subjecting the concentrate to chlorination, using a similar chlorine dose to TOC ratio as would be used in conventional treatment. This concentrated water presented analytical challenges, which were resolved by merging two methods, which provided excellent quality control data while increasing the efficiency of the analysis and offering confirmation data for 19 of the target analytes. In previous studies, the analysis of a broad suite of DBPs was accomplished using two analytical methods, micro liquid-liquid extraction (MLLE) with gas chromatography/electron capture detection (GC/ECD), and solid-phase extraction (SPE) with GC/mass spectrometry (MS). Due to the complex sample matrix in this study, attempts to use conventional MLLE produced thick layers of emulsions that made the separation of a clean solvent layer very difficult. The analysis was labor-intensive and produced low analyte recoveries. However, sample preparation by SPE using a styrene divinylbenzene polymer cartridge proved successful. An automated SPE system was used for all sample preparations. Because GC/ECD offered some detection sensitivity advantages over GC/MS, the SPE extracts were split into two separate vials and both types of instruments were used for sample analyses over a six-month period.

PRESENTATION	Meeting in Charlotte: Methods for the Analysis of Priority DBPs in Ro-Concentrated Drinking Water	11/06/2007

BODIN, N., H. S. WEINBERG, S. W. KRASNER, S. D. RICHARDSON, J. G. PRESSMAN, T. F. SPETH, R. J. MILTNER, AND J. E. SIMMONS. Meeting in Charlotte: Methods for the Analysis of Priority DBPs in Ro-Concentrated Drinking Water. Presented at 2007 Water Quality Technology Conference, Charlotte, NC, November 04 - 08, 2007.
Abstract:	The ability to understand mechanisms of formation and occurrence of disinfection by-products (DBPs) resulting from treatment of natural waters has been limited to those formed at ug/L levels. Toxicological evaluations suggest that many of the DBPs missing from current regulation may be of greater concern to public health, but because of their sub-ug/L levels and resulting challenges to analytical methods, we have little occurrence data for them. Scaling-up drinking water DBPs by concentrating (~130-fold with RO) the total organic carbon from a treated surface water and subjecting the concentrate to chlorination generated higher levels of all DBPs that could then be detectable using currently available methods. Moreover, such a water was used in toxicological evaluations, so characterization of the DBPs formed was critical. This presentation will discuss approaches that have been used to adapt the methods used in our laboratories for the accurate quantitation of many of the priority DBPs in the chlorinated RO concentrates of natural water. The targeted DBPs included, among others, expanded numbers of chlorine-and bromine-containing haloketones, haloacetaldehydes, haloacetonitriles, halonitromethanes, haloacetamides, and halofuranones, as well as iodinated trihalomethanes. Different dilutions were prepared, standard additions used where appropriate, and recovery of analytes calculated. Methods were generated that balanced accuracy with quantifiable detection and subsequently revealed whether priority DBPs might be formed during drinking water treatment.

PRESENTATION	Library-Dependent Microbial Source Tracking of Enterococcus Sp. Using Aflp and Box-Pcr	05/22/2007

BUDINOFF, C. R., J. D. WILLIS, AND M. MOLINA. Library-Dependent Microbial Source Tracking of Enterococcus Sp. Using Aflp and Box-Pcr. Presented at American Society for Microbiology Annual Meeting, Toronto, ON, CANADA, May 21 - 25, 2007.
Abstract:	Library-dependent microbial source tracking (LD MST) methods are one of the approaches used to identify nonpoint sources of fecal contamination in support of total maximum daily load implementation. However, LD MST methods have been questioned due to the high temporal and spatial variability of selected genotypes. Our goal was to examine the temporal variability of Enterococcus sp. isolates through the application of two genotyping LD MST methods, amplified fragment length polymorphism (AFLP) and repetitive polymerase chain reaction with BOX-primers (BOX-PCR). The library consists of 1600 isolates collected over a seasonal cycle at two separate bovine farms. Samples were collected from pre-farm sites (non-impacted), farm sites (impacted), and fecal matter.

PRESENTATION	Molecular Tracking Fecal Contamination in Surface Waters: 16s Rdna Versus Metagenomics Approaches	05/22/2007

LEE, Y. J., M. MOLINA, J. W. SANTO-DOMINGO, O. C. SHANKS, AND M. J. CYTERSKI. Molecular Tracking Fecal Contamination in Surface Waters: 16s Rdna Versus Metagenomics Approaches. Presented at American Society for Microbiology Annual Meeting, Toronto, ON, CANADA, May 21 - 25, 2007.
Abstract:	Microbial source tracking methods need to be sensitive and exhibit temporal and geographic stability in order to provide meaningful data in field studies. The objective of this study was to use a combination of PCR-based methods to track cow fecal contamination in two watersheds. Water, sediment, and cow fecal samples were collected monthly for 12 months from two Georgia watersheds. Watershed 1 (WS1) was under direct cattle impact while watershed 2 (WS2) was only affected through runoff. Various physico-chemical parameters and enterococci counts were measured during sample collection. DNA was extracted from each sample type and challenged against several Bacteroides 16S rDNA-based and metagenome-based assays.

PRESENTATION	Color Counts! Interactions of Colored Organic Matter With Light and Contaminants in Aquatic Environments	03/13/2007

ZEPP, R. G. Color Counts! Interactions of Colored Organic Matter With Light and Contaminants in Aquatic Environments. Presented at Clemson Institute of Environmental Toxicology, Clemson University, Clemson, SC, March 13, 2007.
Abstract:	Slide presentation presented at Clemson University, March 13, 2007.

PRESENTATION	Fate and Effects of the Enantiomers of Chiral Environmental Pollutants	07/09/2007

GARRISON, A. W. Fate and Effects of the Enantiomers of Chiral Environmental Pollutants. Presented at Chirality 2007 - 19th International Symposium on Chirality, San Diego, CA, July 08 - 11, 2007.
Abstract:	Enantiomers, the mirror image isomers of chiral compounds, are known to be selective in their interaction with other chiral molecules, including enzymes and other biochemicals. This holds true for pesticides, about 25% of which are chiral molecules, and other chiral environmental pollutants. Considerable research has shown, for example, that chiral pesticides are often degraded selectively by microbes, leading to differential environmental persistence of the enantiomers. Enantioselectivity is also observed in various organisms after pesticide bioaccumulation. In addition, effects of pesticide enantiomers are often different. This presentation will show examples of enantioselective fate and effects of chiral pesticides and other chiral pollutants, factors that should be taken into account in risk assessment.

PRESENTATION	Meeting in Portugal: Linkage of Exposure and Effects Using Genomics, Proteomics and Metabolomics in Small Fish Models	05/20/2007

COLLETTE, T. W., D. R. EKMAN, Q. TENG, D. C. BENCIC, J. M. LAZORCHAK, R. WANG, M. BREEN, R. CONOLLY, N. DENSLOW, K. WATANABE, E. PERKINS, D. L. VILLENEUVE, AND G. T. ANKLEY. Meeting in Portugal: Linkage of Exposure and Effects Using Genomics, Proteomics and Metabolomics in Small Fish Models. Presented at SETAC Europe 17th Annual Meeting, Porto, PORTUGAL, May 20 - 24, 2007.
Abstract:	With an interdisciplinary team of scientists from U.S. Government Agencies and Universities, we are utilizing zebrafish and fathead minnow to develop techniques for extrapolation of chemical stressor impacts across species, chemicals and endpoints. The linkage of responses across endpoints at multiple biological levels of organization, from the molecular responses to populations, will serve as a basis for identifying and validating mechanistic markers of exposure and effects that can be used for ecological risk assessments. A systems-based approach is being used to define toxicity pathways for model chemicals with well-defined modes/mechanisms of action within the hypothalamic-pituitary-gonadal axis. These pathways serve as a basis for understanding responses of the fish across biological levels of organization, ranging from molecular alterations to adverse effects in individuals to, ultimately, changes in population status. The studies employ a combination of state-of-the-art molecular biology, bioinformatic and modeling approaches, in conjunction with whole animal testing protocols.

PRESENTATION	Application of Advanced in Vitro Techniques to Measure, Understand and Predict the Kinetics and Mechanisms of Xenobiotic Metabolism	05/21/2007

KENNEKE, J. F., W. M. HENDERSON, A. W. GARRISON, S. RITGER, AND C. S. MAZUR. Application of Advanced in Vitro Techniques to Measure, Understand and Predict the Kinetics and Mechanisms of Xenobiotic Metabolism. Presented at International Science Forum on Computational Toxicology, Research Triangle Park, NC, May 21 - 23, 2007.
Abstract:	We have developed a research program in metabolism that involves numerous collaborators across EPA as well as other federal and academic labs. A primary goal is to develop and apply advanced in vitro techniques to measure, understand and predict the kinetics and mechanisms of xenobiotic metabolism. To achieve this, we will focus on inter- and intra-species extrapolation, the various classes of enzymes involved in xenobiotic metabolism, and the role of chirality of both parents and metabolites. Liver microsomes are commonly used as a representative cellular component for mammalian metabolic transformation studies. In vitro metabolism studies have been conducted under well defined experimental conditions using a series of structurally-related model compounds (conazole fungicides) as a proof-of-concept activity.

PRESENTATION	Application of Metabolomics for Improving Ecological Exposure and Risk Assessments	05/21/2007

COLLETTE, T. W., D. R. EKMAN, A. W. GARRISON, W. M. HENDERSON, AND Q. TENG. Application of Metabolomics for Improving Ecological Exposure and Risk Assessments. Presented at International Science Forum on Computational Toxicology, Research Triangle Park, NC, May 21 - 23, 2007.
Abstract:	We have developed a research program in metabolomics that involves numerous partners across EPA, other federal labs, academia, and the private sector. A primary goal is to develop metabolite-based markers that can be used by EPA in ecological exposure and risk assessments. We are focusing this program on ecologically relevant species- in particular, small fish toxicological models. For example, to better understand the impact of endocrine-disrupting chemicals (EDCs) in small fish (fathead minnow, zebrafish), we are conducting metabolomic analyses with multiple tissues (brain, blood, liver, and gonad) and urine. We are developing hypotheses about which tissue- and biofluid-specific metabolite changes will be definitively related to exposure, based on the current understanding of modes-of-action for these chemicals. Results will allow testing of these hypotheses to refine understanding of activity, and will help ensure that molecular markers of EDC exposure are meaningful. While certain metabolites are being specifically targeted in these studies, we will also discern changes in the complete metabolic profile using nuclear magnetic resonance (NMR) and mass spectroscopic (MS) data with statistical approaches that allow capturing subtle changes in less-abundant metabolites. These data are being integrated with genomic, proteomic, and whole organism data from untreated fish and those exposed to known EDCs. Ultimately, these data are used in integrated systems biology models that link: chemical exposures and toxic modes-of-action to ecologically-relevant outcomes.

PRESENTATION	Analysis De La Calidad De Aguas Costeras Culebra, Puerto Rico	03/17/2007

MOLINA, M. Analysis De La Calidad De Aguas Costeras Culebra, Puerto Rico. Presented at Town Hall Meeting, Costaneros Culebra, PUERTO RICO, March 17, 2007.
Abstract:	Presented at a town hall meeting in Costaneros Culebra, Puerto Rico, March 17, 2007.

PRESENTATION	Meeting in San Diego: EPA on-Line Calculators for Site Assessment Calculations	03/21/2007

WEAVER, J. W. Meeting in San Diego: EPA on-Line Calculators for Site Assessment Calculations. Presented at 17th Annual AEHS Meeting and West Coast Conference on Soils, Sediments, and Water, San Diego, CA, March 19 - 22, 2007.
Abstract:	Presented at the AEHS Workshop on Tools for Supporting Cleanup and Closure Decisions at Petroleum Release Sites, San Diego, CA, March 21, 2007.

PRESENTATION	Data for Environmental Modeling (D4em): Background and Example Applications of Data Automation	05/23/2007

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 Example Applications of Data Automation. Presented at International Symposium on Environmental Software Systems, Prague, CZECH REPUBLIC, May 22 - 25, 2007.
Abstract:	Data is a basic requirement for most modeling applications. Collecting data is expensive and time consuming. High speed internet connections and growing databases of online environmental data go a long way to overcoming issues of data scarcity. 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. The Data for Environmental Modeling (D4EM) project demonstrates the development of a comprehensive set of open source software tools that overcome these obstacles by automating the process of populating model input datasets with environmental data available from distributed data sources. Data management and geoprocessing components included in D4EM allow for complex data transformations. Geoprocessing operations are implemented through linkages with open source GIS software. The components also handle metadata and data caching. While this project was initially undertaken to meet the data requirements for two US Environmental Protection Agency (USEPA) modeling systems, i.e. 3MRA (Multimedia, Multipathway, Multi-receptor Risk Assessment) and the BASINS (Better Assessment Science Integrating point and Non-point Sources), its component-based architecture allows it to be integrated into other modeling applications. The components are written in Microsoft .Net languages - C# and Visual Basic .Net. Current data sources include: EPA's STORET data, US Geological Survey (USGS) Terraserver maps and photos, USGS National Water Information System (NWIS) data and the multi agency National Land Cover Dataset (NLCD).

PRESENTATION	Comparison of the Temporal Variability of Enterococcal Clusters in Impacted Streams Using a Multiplex Polymerase Chain Reaction Procedure	03/29/2007

MOLINA, M., M. J. CYTERSKI, J. MAIMES, J. FISHER, AND B. JOHNSON. Comparison of the Temporal Variability of Enterococcal Clusters in Impacted Streams Using a Multiplex Polymerase Chain Reaction Procedure. Presented at 2007 Georgia Water Resources Conference, Athens, GA, March 27 - 29, 2007.
Abstract:	Presented at the Georgia Water Resources Conference, March 27-29, 2007, Athens, GA.

PRESENTATION	Application of Enterococci to Detect and Track Fecal Contamination in Surface Waters	04/26/2007

MOLINA, M. Application of Enterococci to Detect and Track Fecal Contamination in Surface Waters. Presented at Seventh CECIA-IAU Biennial Symposium on Potable Water Issues in Puerto Rico, Bayamón, PUERTO RICO, April 26 - 27, 2007.
Abstract:	Presented at the 7th CECIA-UIPR Potable Water Symposium, April 26-27, 2007, Puerto Rico.

PRESENTATION	High School Advanced Placement Calculus Class Lecture	03/28/2007

WEAVER, J. W. High School Advanced Placement Calculus Class Lecture. Presented at North Oconee High School Advnaced Placement Calculus Class, Bogart, GA, March 28, 2007.
Abstract:	Presented to the North Oconee High School Advanced Placement Calculus Class, March 28, 2007.

PRESENTATION	Elucidating the Role of Electron Transfer Mediators in Reductive Transformations in Natural Sediments	08/19/2007

ZHANG, H. AND E. J. WEBER. Elucidating the Role of Electron Transfer Mediators in Reductive Transformations in Natural Sediments. Presented at 234th National American Chemical Society Meeting, Boston, MA, August 19 - 23, 2007.
Abstract:	To study the identity and reactivity of electron transfer mediators (ETMs) in natural sediments, the reduction kinetics of a glass bead-azo dye complex were measured in abiotic and biotic model systems, as well as in natural sediments. In abiotic model systems, the bead-dye complex was rapidly reduced by chemically reduced quinoid model compounds and NOMs. The presence of Fe(II)/goethite had no effect on reactivity. In biotic model systems, a high density of microbial cells reduced the bead-dye complex. The addition of NOMs, which had not been chemically reduced, increased the rate and extent of reduction of the bead-dye complex. In sediment systems, the bead-dye reduction rates correlated well with organic carbon (OC) contents of both the sediments and their supernatants. These results support the hypothesis that the predominant ETMs in reducing sediments are quinoid functional groups associated with dissolved OC that can be repeatedly reduced through microbial processes.

PRESENTATION	Transformation of Organic Chemicals in Aquatic Systems	04/27/2007

COLON, D. Transformation of Organic Chemicals in Aquatic Systems. Presented at Seventh CECIA-IAU Biennial Symposium on Potable Water Issues in Puerto Rico, Bayamon, PUERTO RICO, April 26 - 27, 2007.
Abstract:	Presented at the Seventh CECIA-IAU Biennial Symposium on Potable Water Issues in Puerto Rico, April 26-27, 2007.

PRESENTATION	Metabolomics in Small Fish Toxicology and Ecological Risk Assessments	06/12/2007

COLLETTE, T. W., D. R. EKMAN, Q. TENG, D. L. VILLENEUVE, AND G. T. ANKLEY. Metabolomics in Small Fish Toxicology and Ecological Risk Assessments. Presented at Metabolomics Society 3rd Annual Conference, Manchester, UK, June 11 - 14, 2007.
Abstract:	The US EPA is tasked with protecting not only humans, but also ecosystems from potentially harmful effects of chemical pollutants. Although lagging behind applications targeted to human endpoints, metabolomics offers great potential in ecotoxicology. Indeed, the advantages of metabolomics (relative to other 'omic techniques) may be more tangible in ecotoxicology because there is often not a sequenced genome available for ecologically relevant species. We are conducting metabolomics studies on small fish, such as the fathead minnow, that are used both as model organisms in ecotoxicology research, and in regulatory testing programs. For example, in a project that involves a large, interdisciplinary team of scientists from US government, academia, and industry, we are integrating transcriptomic, proteomic, and metabolomic data to describe endocrine disruption in the fathead minnow. Our long-tenn goal is to understand how chemical exposures are linked through these early molecular changes to whole-organism adverse outcomes and, ultimately, to changes in population status. To achieve this goal, a systems-based approach is being used to define toxicity pathways for model chemicals with well defined modes of action within the hypothalamic-pituitary-gonadal (HPG) axis of the fathead minnow. We will describe the unique role that metabolomics plays in this ecotoxicological application, and also the role that we envision for metabolomics in regulatory decision making.

PRESENTATION	Gasoline Composition in the U.S. 1976-2007	04/17/2007

WEAVER, J. W. Gasoline Composition in the U.S. 1976-2007. Presented at Clemson Hydrogeology Symposium, Clemson, SC, April 17, 2007.
Abstract:	Presentation presented at Clemson University, April 17, 2007.

PRESENTATION	Occurrence and Toxicity of Iodinated Disinfection By-Products in Drinking Water	06/18/2007

RICHARDSON, S. D., J. J. ELLINGTON, F. G. CRUMLEY, K. BUETTNER, J. J. EVANS, B. C. BLOUNT, L. K. SILVA, F. L. CARDINALI, M. J. PLEWA, E. D. WAGNER, G. W. LUTHER III, AND T. J. WAITE. Occurrence and Toxicity of Iodinated Disinfection By-Products in Drinking Water. Presented at Micropol and Ecohazard Conference 2007, Frankfurt, GERMANY, June 17 - 20, 2007.
Abstract:	As part of a recent Nationwide Disinfection By-Product (DBP) Occurrence Study, iodo-acids were identified for the first time as DBPs in drinking water disinfected with chloramines. The iodo-acids identified included iodoacetic acid, bromoiodoacetic acid, (E)-3-bromo-3-iodo-propenoic acid, (Z)-3-bromo-3-iodo-propenoic acid, and (E)-2-iodo-3-methylbutenedioic acid. There is concern because toxicity studies have revealed that iodoacetic acid is highly cytotoxic and genotoxic, with a genotoxicity potency 2X higher than bromoacetic acid, the most genotoxic of the regulated haloacetic acids. Also, many drinking water treatment plants in the United States have switched from chlorine to chloramines for treatment. New evidence indicates that the formation of iodinated DBPs will be higher in chloraminated drinking water than in chlorinated drinking water. For this research, a gas chromatography (GC)/negative chemical ionization mass spectrometry (MS) method was developed to measure the iodo-acids in drinking waters across the U.S., and two iodinated trihalomethanes (THMs) (dichloroiodomethane and bromochloroiodomethane) were measured using a GC/high resolution electron ionization-MS method with isotope dilution. Iodoacetic acid, bromoiodoacetic acid, and (E)-2-iodo-3-methylbutenedioic acid were found in most of the plants sampled, at sub-ppb to low-ppb levels; the two iodo-THMs were found at all plants sampled, at low ppb or sub-ppb levels (with a high of 10.2 ppb for bromochloroiodomethane). New toxicity work is underway for the other iodo-acids (beyond iodoacetic acid) and for the two iodo-THMs; these new toxicity data will be presented, along with measurements of iodide in the source waters.

PRESENTATION	Heuristic Optimization and Algorithm Tuning Applied to Sorptive Barrier Design	02/19/2007

MATOTT, L. S., S. L. BARTELT-HUNT, A. J. RABIDEAU, AND K. R. FOWLER. Heuristic Optimization and Algorithm Tuning Applied to Sorptive Barrier Design. Presented at SIAM Conference on Computational Science and Engineering, Costa Mesa, CA, February 19 - 23, 2007.
Abstract:	While heuristic optimization is applied in environmental applications, ad-hoc algorithm configuration is typical. We use a multi-layer sorptive barrier design problem as a benchmark for an algorithm-tuning procedure, as applied to three heuristics (genetic algorithms, simulated annealing, and particle swarm optimization). Design problems were formulated as combinatorial optimizations where the sorptive layers of a landfill liner were selected to minimize contaminant transport. Results indicate that formal pre-tuning can improve algorithm performance and provide insight into the physical processes that control environmental systems.

PRESENTATION	Enantioselective Formation of the Triazole Fungicide Triadimenol from Triadimefon in Mammal and Fish Hepatic Microsomes	08/20/2007

KENNEKE, J. F., C. S. MAZUR, AND A. W. GARRISON. Enantioselective Formation of the Triazole Fungicide Triadimenol from Triadimefon in Mammal and Fish Hepatic Microsomes. Presented at 234th National American Chemical Society Meeting, Boston, MA, August 19 - 23, 2007.
Abstract:	Triazole containing compounds are used extensively in both agriculture and medicine for the control of fungal infections. Recently, emphasis has been placed on the potential adverse effects of these compounds within mammalian systems. Triadimefon is a common agricultural fungicide. It contains one chiral center, and forms a second chiral center when metabolized to triadimenol, another commercially used fungicide. We have studied the enantioselective metabolism of the individual enantiomers and racemate of triadimefon to triadimenol in microsomes from male and female mammals, fish and invertebrates. In all species and genders, (+) triadimefon was metabolized more quickly than (-) with the enantiomeric fractions of the resulting four triadimenol enantiomers being species specific. Inhibitor and pure enzyme studies indicated that triadimefon was metabolized by a short-chain dehydrogenase/reductase and may disrupt steroid pathways. These findings will be put in context of species differences, potential impacts on steroidogenesis and tumorigenesis, and risk assessment.

PRESENTATION	Meeting in Germany: Emerging Environmental Contaminants and Current Issues	06/25/2007

RICHARDSON, S. D. Meeting in Germany: Emerging Environmental Contaminants and Current Issues. Presented at Seminar at German Federal Environmental Agency, Berlin, GERMANY, June 27, 2007.
Abstract:	Much has been achieved in the way of environmental protection over the last 30 years. However, as we learn more, new concerns arise (including potential adverse health effects, bioaccumulation, and widespread distribution). 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), pharmaceuticals, perfluorooctanoic acid (PFOA), polybrominated diphenyl ether (PBDE) flame retardants, 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. Concerns with PFOA and PBDEs include widespread global distribution in the blood of the general human population and in wildlife, as well as potential health effects, including cancer and developmental toxicity. Pharmaceuticals are of concern due to antibiotic resistance and potential endocrine disrupting effects. Some of the emerging contaminants (e.g., nitrosamines, PBDE flame retardants, and pesticide degradation products) are currently listed on the proposed Unregulated Contaminants Monitoring Rule (UCMR2), which requires EPA to select five or more contaminants every five years to consider for regulation. Other emerging contaminants are listed on the Contaminant Candidate List (CCL), which identifies drinking water contaminants that might be regulated by EPA at a future date, and other emerging contaminants are currently under consideration for the UCMR and the 3rd CCL. The status and health/environmental issues with these emerging environmental contaminants will be discussed, as well as analytical methods used to measure them.

PRESENTATION	Organophosphorus Pesticide Degradation Pathways During Drinking Water Treatment	06/18/2007

DUIRK, S. E. AND L. M. DESETTO. Organophosphorus Pesticide Degradation Pathways During Drinking Water Treatment. Presented at Micropol and Ecohazard Conference 2007, Frankfurt, GERMANY, June 17 - 20, 2007.
Abstract:	The objective of this work was to investigate organophosphorus (OP) pesticide transformation pathways as a class in the presence of aqueous chlorine. Seven priority OP pesticides were examined for their reactivity with aqueous chlorine: chlorpyrifos (CP), parathion (PA), diazinon (DZ), malathion (MA), methidathion (ME), tebupirimfos (TE), and chlorethoxyfos (CE). These OP pesticides were selected for their use patterns as well as their diverse structures and chemical properties. The experimental results will be used to determine intrinsic rate coefficients and model the reaction between aqueous chlorine and OP pesticides. Molecular descriptors will then be used to correlate reactivity with chlorine to OP structural characteristics. Structural 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	Virtual Beach Course Introductory Module	05/01/2007

FRICK, W. E. AND Z. GE. Virtual Beach Course Introductory Module. Presented at Training Course at the University of Wisconsin, Oshkosh, Oshkosh, WI, May 01 - 02, 2007.
Abstract:	Training course presented at University of Wisconsin, Oshkosh, May 1-2, 2007.

PRESENTATION	Seminar in New Jersey: the Next Generation of Drinking Water Disinfection By-Products and Health Issues	05/02/2007

RICHARDSON, S. D. Seminar in New Jersey: the Next Generation of Drinking Water Disinfection By-Products and Health Issues. Presented at Seminar at the New Jersey Institute of Technology, Newark, NJ, May 02, 2007.
Abstract:	Presentation given at the New Jersey Institute of Technology, May 2, 2007.

PRESENTATION	Chiral Methods and Analysis of PCB 95 and Cis-Permethrin in Environmental Samples from the Ctepp Study	07/09/2007

ULRICH, E. M., T. CUMMINGS, A. W. GARRISON, AND M. K. MORGAN. Chiral Methods and Analysis of PCB 95 and Cis-Permethrin in Environmental Samples from the Ctepp Study. Presented at Chirality 2007 - 19th International Symposium on Chirality, San Diego, CA, July 08 - 11, 2007.
Abstract:	The creation of chiral chromatography techniques significantly advanced the development of methods for the analysis of individual enantiomers of chiral compounds. These techniques are being employed at the US EPA for human exposure and ecological research studies with indoor samples, sediment, plants, and biota. A variety of chemicals including legacy persistent organic pollutants and current use pesticides are being investigated. One such project is the Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) study. The CTEPP study focuses on measuring the exposures of preschool children to chemicals, including pesticides and polychlorinated biphenyls (PCBs), found in their everyday environments (i.e., homes and daycare centers). Chiral gas chromatographic mass spectrometry methods were developed and the enantiomer fractions of cis-permethrin and PCB 95 were measured in selected environmental samples. Enantiomer fractions [EF = chromatographic peak area (+) enantiomer / sum of (+) and (-) areas] can be used to implicate sources, distinguish between biological and other types of degradation, and give a more complete picture of environmental concentrations. cis-Permethrin has a racemic signature, or an EF of 0.5, in the three matrices analyzed (floor dust, hard floor surface wipe, and food preparation surface wipe). These results suggest that no enantioselective biological degradation of permethrin has occurred. PCB 95 EFs range between 0.48 and 0.69 in eight different matrices (transferable residues from surfaces; floor dust; food preparation surface, hard floor surface, and dermal wipes; indoor and outdoor air; and soil). The nonracemic EFs in the environmental samples indicate that some enantioselective biological degradation has occurred to this PCB over time, either in the indoor environment, or prior to translocation to the indoor environment. These results highlight the importance of the enantiomers of chiral compounds because some degradation pathways, usually biological ones, can change the distribution of enantiomers in the environment. This may lead to differential exposure to enantiomers, as is the case with PCB 95. The toxicity of enantiomers can also vary. When these two factors are combined, a differential risk to humans and other organisms may also be revealed.

PRESENTATION	Modeling Wave-Induced Entrainment of Mud in Newnans Lake, Florida	09/25/2007

HAYTER, E. J., M. JAIN, AND A. J. MEHTA. Modeling Wave-Induced Entrainment of Mud in Newnans Lake, Florida. Presented at INTERCOH '07- 9th International Conference on Nearshore and Estuarine Cohesive Sediment Transport Processes, Brest, FRANCE, September 25 - 28, 2007.
Abstract:	Many shallow lakes in the southeastern US are eutrophic, and as such, the water quality in these lakes is of concern to state and federal environmental regulatory agencies. Some of these lakes have been classified as impaired with one or more nutrients being the stressor. For these water bodies, a TMDL (total maximum daily load) must be established for the purpose of improving the water quality. Establishment of a TMDL requires estimation of nutrient influxes and effluxes as well as sources and/or sinks of nutrients within the lake. Most of these eutrophic lakes are typically loaded with fine-grained, organic-rich mud at the bottom. Nutrients are usually adsorbed to the fine-grained sediments and organic matter that constitute the mud. Sorbed nutrients (i.e., phosphate, ammonium) in the mud may be re-introduced to the water column through one or more of the following processes: desorption of the nutrients from the mud particles; diffusive and possibly groundwater-induced advective transport of the dissolved nutrients through the pore water in the mud; diffusive and bioturbation enhanced flux of the dissolved nutrients from the surficial mud layer to the water column; and entrainment of surficial mud particles. Thus, estimation of internal loading of nutrients from the mud to the water column requires the ability to simulate these processes. In this study the ability to simulate one of these processes - the entrainment of organic-rich mud in a shallow lake - will be investigated using the mud entrainment model developed by Jain.

PRESENTATION	Using Hydrographic Data and the EPA Virtual Beach Model to Test Predictions of Beach Bacteria Concentrations	11/05/2007

FRICK, W. E. AND Z. GE. Using Hydrographic Data and the EPA Virtual Beach Model to Test Predictions of Beach Bacteria Concentrations. Presented at ERF 2007, Providence, RI, November 04 - 08, 2007.
Abstract:	A modeling study of 2006 Huntington Beach (Lake Erie) beach bacteria concentrations indicates multi-variable linear regression (MLR) can effectively estimate bacteria concentrations compared to the persistence model. Our use of the Virtual Beach (VB) model affirms that fact. VB is public-domain software developed at the USEPA, including an MLR model. The study involved a suite of explanatory variables, however stream flow variables describing point sources more directly, while available, were not used. Results presented by Nevers et al. (2007) showed that current reversals were associated with changes in beach bacteria concentrations. This work analyzes available hydrological data, adjusting for travel times, to assess their model potential. If the differences are found to be statistically significant, the work should help to put the importance of source strength into perspective to other important explanatory variables.

PRESENTATION	Predictive Modeling of Light-Induced Mortality of Enterococci Faecalis in Recreational Waters	11/14/2007

ZEPP, R. G., R. JONES, J. WILLIS, M. J. CYTERSKI, AND M. MOLINA. Predictive Modeling of Light-Induced Mortality of Enterococci Faecalis in Recreational Waters. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Milwaukee, WI, November 11 - 15, 2007.
Abstract:	One approach to predictive modeling of biological contamination of recreational waters involves the application of process-based approaches that consider microbial sources, hydrodynamic transport, and microbial fate. This presentation focuses on one important fate process, light-induced mortality. Fecal indicator bacteria such as enterococci have been used to assess possible contamination of beaches and other recreational waters. Past studies have indicated that sunlight plays an important role in altering concentrations of culturable enterococci and other indicator microorganisms in beach environments. Here we report studies of the light-induced mortality of one species of enterococci, Enterococci faecalis, under various conditions in Nanopure and natural waters. Direct exposure of the bacteria to solar radiation in all waters resulted in rapid mortality of the enterococci with half-lives of a few minutes. In the dark, mortality half-lives were much longer, on the order of several days. Mortality rates of E. faecalis were determined in a series of irradiations of the bacteria that used simulated solar radiation that was passed through light filters that blocked different parts of the ultraviolet and visible spectral region. The mortality rates and spectral irradiance were then analyzed by the Rundel techllique to develop biological weighting functions (BWFs) for the light-induced mortality. The BWFs were then combined with other data concerning underwater solar spectral irradiance to model the light-induced mortality of E. faecalis in selected recreational waters.

PRESENTATION	Meeting in Indianapolis: Chlorinated Vs. Chloraminated Drinking Water: Toxicity-Based Identification of DBPs Using Esi-MS and Esi-MS/MS	06/05/2007

RICHARDSON, S. D., F. G. CRUMLEY, F. FASANO, M. J. PLEWA, E. D. WAGNER, L. N. WILLIAMSON, M. G. BARTLETT, T. H. MIZE, P. M. ANGEL, AND R. ORLANDO. Meeting in Indianapolis: Chlorinated Vs. Chloraminated Drinking Water: Toxicity-Based Identification of DBPs Using Esi-MS and Esi-MS/MS. Presented at 55th ASMS Conference on Mass Spectrometry, Indianapolis, IN, June 03 - 07, 2007.
Abstract:	Drinking water disinfection by-products (DBPs) are of concern because some epidemiologic studies have shown that they are associated with cancer or adverse reproductive/developmental effects in human populations. While more than 500 DBPs have been reported in drinking water, there is almost no information on high molecular weight DBPs (>1000 Da), which are included to comprise >50% of the total organic halide (TOX) from chlorinated drinking water. None of these high molecular weight halogenated by-products have ever been precisely identified, and there is no information on potential toxicity of this high molecular weight fraction. The goal of this research is to use a bio-assay directed approach to focus identification work on the most toxicologically important DBPs. FT-MS analyses of drinking water fractions revealed negative mass defects in ions for chlorinated and chloraminated water, whereas positive mass defects were observed for the raw, non-treated drinking water. In addition, halogen patterns were evident in the ultra-high resolution mass spectral data, and loses of HCl, HBr, and CO2 were evident in the MS/MS spectra. Genotoxicity results of the molecular weight fractions of chlorinated and chloraminated water revealed the <1 kDa fraction to be the most genotoxic. The cytotoxicity and genotoxicity of the >5 kDa fraction was the least toxic of the molecular weight fractions of drinking water.

PRESENTATION	Bacterial Mortality Due to Solar Radiation, Comparing Experimental and Statistical Evidence	11/12/2007

FRICK, W. E. AND Z. GE. Bacterial Mortality Due to Solar Radiation, Comparing Experimental and Statistical Evidence. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Milwaukee, WI, November 11 - 15, 2007.
Abstract:	Many researchers report that sunlight is a primary stressor of beach indicator bacteria. Some water quality models include code that quantifies the effect of radiation on bacterial decay. For example, the EPA Visual Plumes model includes two coliform and one enterococcus submodels, including the Mancini (1978) coliform model that expresses bacterial mortality as functions of solar radiation, salinity, and temperature. The Environmental Protection Agency (EPA) has developed and tested a program called Virtual Beach (VB), public-domain software. Among other functions, VB facilitates the development of site-specific multi-variable linear regression (MLR) models. Studies, including those using VB, show that MLR models can produce good estimates, both nowcasts and forecasts, using real-time and forecasted explanatory variables, such as turbidity, cloud cover, wind, and rainfall. In this study we investigate the role solar radiation plays in determining bacterial decay. Based on data published by the U.S. Geological Survey for Huntington Beach (Lake Erie) and other sources, including solar radiation data measured by the Ohio State University's Ohio Agricultural Research and Development Center (OARDC) at their nearby Avon site, we used VB to examine the role of radiation on bacterial decay. This work helps to contrast the influence of solar radiation to other factors affecting the fate of bacteria in beach water.

PRESENTATION	Frames and 3mra: An Integrated Modeling Infrastructure and Example Resident Modeling System	01/30/2007

BABENDREIER, J. E. AND G. F. LANIAK. Frames and 3mra: An Integrated Modeling Infrastructure and Example Resident Modeling System. Presented at CREM/ERD Integrated Modeling for Integrated Environmental Decision-Making Workshop, Research Triangle Park, NC, January 30 - February 01, 2007.
Abstract:	Oral presentation given at the CREM/ERD Integrated Modeling Workshop, January 30, 2007.

PRESENTATION	Using Chirality to Inform the Metabolism of Triadimefon to Triadimenol: A Cross-Species Examination	11/12/2007

OVERMYER, J. P., J. F. KENNEKE, C. S. MAZUR, J. K. AVANTS, A. W. GARRISON, M. DELORENZO, AND P. KEY. Using Chirality to Inform the Metabolism of Triadimefon to Triadimenol: A Cross-Species Examination. Presented at Society for Environmental Toxicology and Chemistry Annual Meeting, Milwaukee, WI, November 11 - 15, 2007.
Abstract:	Triadimefon is a systemic agricultural fungicide of the conazole class whose metabolite, triadimenol, provides the majority of the actual fungicidal activity; i.e. inhibition of steroid demethylation. Triadimenol is also registered and used as a fungicide. Both chemicals are chiral: triadimefon has one chiral center with two enantiomers while its enzymatic reduction to triadimenol produces a second chiral center and four enantiomers (two diastereomers). Our research involves treatment of microsomes prepared from a variety of mammalian, fish and invertebrate species with triadimefon, followed by analysis of the triadimenol metabolites using a chiral BGB-172 column in a GC-MS system. The two triadimefon enantiomers and the four triadimenol enantiomers are separated from each other so that the stereoselectivity of loss of the parent and formation of the metabolite can be observed. In vitro exposure of microsomes from seven species with subsequent chiral analysis shows that the (+)-enantiomer of triadimefon is transformed to triadimenol faster than the (-)-enantiomer in all these microsomes, but that the pattern of stereoselectivity of formation of the latter differs for all species. Since it is known that the diastereomers of triadimenol differ in their toxicities, the resulting biological activity of this metabolite most likely depends on the pattern of stereoisomers formed. Interspecies comparison by chiral analysis may be useful in probing the metabolism of pesticide-exposed organisms as well as improving cross-species extrapolation for risk assessment.

PRESENTATION	Cross-Species Comparison of Conazole Fungicide Metabolites Using Rat and Rainbow Trout (Onchorhynchus Mykiss) Hepatic Microsomes and Purified Human Cytochrome P450 3a4	10/10/2007

MAZUR, C. S. AND J. F. KENNEKE. Cross-Species Comparison of Conazole Fungicide Metabolites Using Rat and Rainbow Trout (Onchorhynchus Mykiss) Hepatic Microsomes and Purified Human Cytochrome P450 3a4. Presented at 8th International Society for the Study of Xenobiotics, Sendai, JAPAN, October 09 - 12, 2007.
Abstract:	Conazoles represent a unique class of azole-containing fungicides that are widely used in both pharmaceutical and agriculture applications. The antifungal property of conazoles occurs via complexation with cytochrome P450 monooxygenases (CYP) responsible for mediating fungal cell wall synthesis. This CYP-directed mode of action has cause for concern in vertebrate species with regards to inhibiting a broad spectrum of CYP-detoxifying mechanisms. Most toxicological screening assays are designed with mammalian (rodent) receptors or tissues, thus a major complication for environmental risk assessment is the degree of cross-species extrapolation used from mammalian to aquatic systems. Although inherently complex, metabolite identification is critical to risk assessment since products formed may pose a greater toxicological threat than the parent molecule. In this report, LC/MS and LC-MS/MS were implemented to determine in vitro metabolic profiles for thirteen different conazoles using rat and rainbow trout (Oncorhynchus mykiss) hepatic microsomes and purified human CYP 3A4. Our results indicate that rat and trout interspecies metabolite comparison of conazole fungicides was well conserved via both aromatic and aliphatic hydroxylation and carbonyl reduction processes. In addition, biotransformation screening clearly indicates that the phase I mode of action observed with human CYP 3A4 was strongly correlated to that of both rat and trout microsomes.

PRESENTATION	Forecasts and Sensitivity of PCB Bioaccumulation in Fish of Lake Hartwell, South Carolina, USA	11/12/2007

RASHLEIGH, B., M. C. BARBER, AND D. M. WALTERS. Forecasts and Sensitivity of PCB Bioaccumulation in Fish of Lake Hartwell, South Carolina, USA. Presented at Society for Environmental Toxicology and Chemistry Annual Meeting, Milwaukee, WI, November 11 - 15, 2007.
Abstract:	The EPA aquatic ecosystem model AQUATOX was applied to the Twelvemile Creek arm of Lake Hartwell, which received 400,000 lbs of PCBs from the Sangamo-Weston Superfund Site near Clemson, South Carolina, USA, from 1955 until the early 1990s. AQUATOX was used to characterize food web dynamics, simulate bioaccumulation, and identify important pathways of contaminants to higher trophic levels. The model was also used to estimate the time needed for PCB concentrations in all fish to be reduced to target recovery levels. Under the scenario of constant tributary flows, no new external loadings, and a linear decline of existing loadings, the model calculated that target recovery levels should occur in approximately 6 years. We used new capabilities in AQUATOX Release 3 for comprehensive sensitivity analysis of the model results. A sensitivity analysis of fish PCB concentrations to a 10% decrease in individual parameter values revealed the strongest responses to fish consumption rate (+200 for bass%); input nutrient concentrations (+179% for catfish), and optimum temperatures for fish (+140 for bass%). Largemouth bass and channel catfish were more generally sensitive to parameters changes than shad and bluegill. High sensitivities of certain parameters indicate uncertainty in forecasts for bioaccumulation in this system.

PRESENTATION	A Review of Bioaccumulation Modeling Approaches for Persistent Organic Pollutants	11/12/2007

BARBER, M. C., W. R. MUNNS, JR., AND B. RASHLEIGH. A Review of Bioaccumulation Modeling Approaches for Persistent Organic Pollutants. Presented at Society for Environmental Toxicology and Chemistry Annual Meeting, Milwaukee, WI, November 11 - 15, 2007.
Abstract:	Persistent organic pollutants and mercury are likely to bioaccumulate in biological components of the environment, including fish and wildlife. The complex and long-term dynamics involved with bioaccumulation are often represented with models. Current scientific developments in this area include how to adequately (1) represent diet, dermal, and gill exchanges, (2) represent food web structure and dynamics, (3) link bioaccumulation models to chemical fate and transport models, (4) incorporate residue-based effects models, and (5) integrate to ecological and human health dietary risk assessment models. The accurate representation of bioaccumulation in models is critical because such models are often used in decision-support. Here, we review and discuss bioaccumulation representations that are needed to support decisions about environmental protection, restoration, and enhancement.

PRESENTATION	Identifying Indicators of Reactivity for Chemical Reductants in Anoxic and Anaerobic Sediments	11/14/2007

ZHANG, H. AND E. J. WEBER. Identifying Indicators of Reactivity for Chemical Reductants in Anoxic and Anaerobic Sediments. Presented at Society for Environmental Toxicology and Society Annual Meeting, Milwaukee, WI, November 13 - 17, 2007.
Abstract:	To develop reaction transport models describing the movement of redox-active organic contaminants through contaminated sediments and aquifers, it is imperative to know the identity and reactivity of chemical reductants in natural sediments and to associate their reactivity with physicochemical indicators that can be readily measured. For this purpose the reactivity, as defined by the reduction rate of p-cyanonitrobenzene (pCNB), of twenty-one natural sediments with either 3-d (anoxic conditions) or 5-w (anaerobic conditions) pre-incubation periods was studied.

PRESENTATION	Dissolved Organic Carbon and Dissolved Carbon Dioxide Concentrations and Export in Georgia Piedmont Headwater Streams	07/08/2007

BURKE, R. A. AND J. MOLINERO. Dissolved Organic Carbon and Dissolved Carbon Dioxide Concentrations and Export in Georgia Piedmont Headwater Streams. Presented at Gordon Research Conference on Catchment Science: Interactions of Hydrology, Biology, and Geochemistry, New London, NH, July 08 - 13, 2007.
Abstract:	The South Fork Broad River (SFBR) drains about 550 km2 of the Georgia Piedmont. The SFBR watershed is primarily rural and undeveloped although the human population increased by about 25% between 1990 and 2000. Forestry and agriculture are the main land uses. Agriculture consists mainly of pasture and poultry operations. Northern Georgia is a major area of US poultry production and massive amounts of poultry litter are generated, most of which is applied to pastures near the production site. Further, 90% of the homes are on septic tanks. Given all these sources, there is potential for contamination of headwater streams by organic waste contamination. We monitored concentrations of dissolved organic carbon (DOC), dissolved CO2, pH, temperature, flow, and other parameters in 17 SFBR headwater streams on a monthly basis for about a year. We calculated bicarbonate concentrations from the pH and temperature data, and total dissolved carbon (TDC) as the sum of DOC, dissolved CO2, and bicarbonate. Land use in the small watersheds that we studied was derived from the National Land Cover Data database. Mean concentrations of DOC, dissolved CO2, bicarbonate and TDC, and annual DOC export were positively correlated with land cover (% pasture). In contrast, annual export of TDC, dissolved CO2, and bicarbonate were not correlated with land use suggesting that hydrological controls are relatively more important for these parameters. We hypothesize that elevated DOC concentrations and DOC export observed in streams draining watersheds with extensive pasture land use result from input of organic wastes to the soils in excess of terrestrial ecosystem processing capacity. Contamination of streams as a result of the excessive land application of organic wastes is a concern because we observed dissolved oxygen concentrations below the minimum allowed for non-trout waters (4 mg/L) during the summer in some of the streams.

PRESENTATION	Metabolomics as a Tool for Discriminating Among Adaptive, Compensatory, and Toxic Responses Upon Exposure of Small Fish to Edcs	11/14/2007

EKMAN, D. R., T. W. COLLETTE, Q. TENG, G. T. ANKLEY, D. MARTINOVIC, K. M. JENSEN, AND D. L. VILLENEUVE. Metabolomics as a Tool for Discriminating Among Adaptive, Compensatory, and Toxic Responses Upon Exposure of Small Fish to Edcs. Presented at Society for Environmental Toxicology and Chemistry Annual Meeting, Milwaukee, WI, November 13 - 17, 2007.
Abstract:	Determining the impact(s) of exposure on aquatic organisms by endocrine disrupting compounds (EDCs) is essential 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 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. Therefore, 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	Measurement of Nanoparticles in Water	10/14/2007

BOUCHARD, D. Measurement of Nanoparticles in Water. Presented at 80th Annual Water Environment Federation Technical Exhibition and Conference, San Diego, CA, October 13 - 17, 2007.
Abstract:	Measuring nanoparticles in water differs from traditional dissolved solute measurement in several ways. The most salient difference is that nanoparticles are colloids rather than solutes and therefore are subject to the interparticle interactions (mainly electrostatic and Van der Waals forces) that determine whether a colloid remains dispersed and stable in water, or whether particle aggregation and sedimentation is favored. Subsequently, care needs to be taken from sample collection to instrumental measurement in the lab to ensure that the sample being measured is representative of the water body at the point of collection. The primary concern here is to maintain the sample water chemistry so that the colloidal state of the nanoparticles is held constant.

PRESENTATION	The Next Generation of Disinfection By-Products: Uncovering High Molecular Weight DBPs and Other Emerging DBPs	06/25/2007

RICHARDSON, S. D. The Next Generation of Disinfection By-Products: Uncovering High Molecular Weight DBPs and Other Emerging DBPs. Presented at Invited Seminar at EAWAG, Zurich, SWITZERLAND, June 25, 2007.
Abstract:	Oral presentation at EAWAG in Zurich, Switzerland, June 25, 2007.

PRESENTATION	Meeting in Switzerland: the Next Generation of Drinking Water Disinfection By-Products and Health Issues	06/22/2007

RICHARDSON, S. D. Meeting in Switzerland: the Next Generation of Drinking Water Disinfection By-Products and Health Issues. Presented at Seminar at Agroscope, Wadenswil, SWITZERLAND, June 22, 2007.
Abstract:	Oral presentation at Agroscope, Wadenswil, Switzerland, June 22, 2007.

PRESENTATION	Environmental Consequences of Land Use Change: Accounting for Complexity With Agent-Based Models	06/08/2007

PURUCKER, S. T., M. J. CYTERSKI, R. S. PARMAR, B. RASHLEIGH, AND K. L. WOLFE. Environmental Consequences of Land Use Change: Accounting for Complexity With Agent-Based Models. Presented at 2007 Annual Conference of the North American Association of Computational Social and Organizational Sciences, Atlanta, GA, June 07 - 09, 2007.
Abstract:	The effects of people on ecosystems and the impacts of ecosystem services on human well-being are being viewed increasingly as an integrated system. Demographic and economic pressures change a variety of ecological indicators, which can then result in reduced quality of ecosystem services and a concomitant reduction in human well-being. Of particular interest is the effect of human activities, including changes in land use and cover, species introduction and removal, and climate change, on the quality and spatial distribution of habitat. However, using reductionist approaches to predict the effects of land use change on ecosystem services is difficult. Consensus concerning model development and application must be achieved among many stakeholders with diverse opinions. The models ultimately constructed often consist of simple approaches, dominated by direct cause-effect relationships, which ignore important feedback mechanisms. In addition, effects of ecological change are complex in that they exhibit emergent behavior that is non-linear and sensitive to initial conditions. These complex relationships can be assessed in the context of an adaptive system. Agent-based models that account for human impacts on habitat can be used to assess these problems better, and can be integrated with ecological effects models to improve planning and forecast effects of land use change, as well as to evaluate mitigation actions under alternative futures.

PRESENTATION	Bats and Bt Insect Resistance on Agricultural Landscapes	08/22/2007

PURUCKER, S. T., P. FEDERICO, T. G. HALLAM, K. S. KENNARD, G. F. MCCRACKEN, AND J. K. WESTBROOK. Bats and Bt Insect Resistance on Agricultural Landscapes. Presented at 14th International Bat Research Conference, Merida, MEXICO, August 19 - 23, 2007.
Abstract:	A landscape model that utilizes land cover classification data, insect life history, insect movement, and bat foraging pressure is developed that addresses the implementation of genetically modified crops in the Winter Garden region of Texas. The principal strategy for delaying resistance in insects to Bt modified crops is a combination of a high Bt dose to the insect in the crop and the creation of a spatial refuge in close proximity so that susceptible insects will mate with insects that develop resistance. We examine the resistance population dynamics of the pest insects on a landscape of genetically-modified crops and refuges, including insect productivity for different land cover classifications and the effects of mass migration of susceptible moths from Mexico, then explore the impacts that differential foraging of Mexican free-tailed bats (Tadarida brasiliensis) on refuge insects can have on the dynamics of time to resistance. Model results have implications for the impacts of biotechnology on large bat populations, insect resistance monitoring in this area, and the value of agroecosystem services provided by bats.

PRESENTATION	Sada: A Freeware Decision Support Tool Integrating GIS, Sample Design, Spatial Modeling and Risk Assessment (Slide Presentation)	05/24/2007

STEWART, R. N., S. T. PURUCKER, AND G. E. POWERS. Sada: A Freeware Decision Support Tool Integrating GIS, Sample Design, Spatial Modeling and Risk Assessment (Slide Presentation). Presented at ISESS 2007 Conference, Prague, CZECH REPUBLIC, May 22 - 25, 2007.
Abstract:	Spatial Analysis and Decision Assistance (SADA) is a Windows freeware program that incorporates tools from environmental assessment into an effective problem-solving environment. SADA was developed by the Institute for Environmental Modeling at the University of Tennessee and 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 began in the middle 1990s as a simple tool for integrating human health risk with spatial modeling tools. Since then, SADA has continued as an evolving freeware product targeted to individuals needing the integration or expansion of existing models into a spatial context. Because of the varied user base, SADA was engineered with an open and highly scaleable environment that in most cases allows additional functionality without an apparent increase in complexity. As a result, applications of SADA have extended into other disciplines that place strong emphasis on the spatial distribution of data. This paper provides an overview of the central functions of SADA and discusses how we addressed the problem of presenting complex and integrated models in a tractable manner. Information on SADA and a free download of the program can be found at http://www.tiem.utk.edu/~sada/.

PRESENTATION	Spatial Dynamics of Land Cover and Infectious Disease Risk	04/16/2007

PURUCKER, S. T., B. RASHLEIGH, K. L. WOLFE, M. J. CYTERSKI, R. S. PARMAR, AND L. M. PRIETO. Spatial Dynamics of Land Cover and Infectious Disease Risk. Presented at 2007 Biomedical and Health Sciences Symposium on Climate, Ecology and Infectious Disease, Athens, GA, April 16 - 17, 2007.
Abstract:	Climate changes may allow for vector-transmitted tropical diseases to spread into temperate areas. Areas of low ecological diversity are at higher risk of infectious disease transmission due to decreased zooprophylaxis, the diversion of disease carrying insects from humans to animals. Human demographic and economic pressures cause land cover changes that directly impact community diversity, resulting in reduced quality of ecosystem services such as zooprophylaxis and a concomitant reduction in human well-being. Studies that forecast the impact of climate change on disease transmission need to be coupled with dynamic models of land cover in order to properly address infectious disease transmission risks. This poster surveys available approaches and tools for simulating land cover dynamics.

PRESENTATION	Meeting in Chicago: Sada: A Freeware Decision Support Tool Integrating GIS, Sample Design, Spatial Modeling, and Environmental Risk Assessment	03/29/2007

PURUCKER, S. T. AND R. N. STEWART. Meeting in Chicago: Sada: A Freeware Decision Support Tool Integrating GIS, Sample Design, Spatial Modeling, and Environmental Risk Assessment. Presented at American Chemical Society National Meeting, Chicago, IL, March 25 - 29, 2007.
Abstract:	Spatial Analysis and Decision Assistance (SADA) is a Windows freeware program that incorporates tools from environmental assessment into an effective problem-solving environment. SADA was developed by the Institute for Environmental Modeling at the University of Tennessee and 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 began in the middle 1990s as a simple tool for integrating human health risk with spatial modeling tools. Since then, SADA has continued as an evolving freeware product targeted to individuals needing the integration or expansion of existing models into a spatial context. Because of the varied user base, SADA was engineered with an open and highly scaleable environment that in most cases allows additional functionality without an apparent increase in complexity. As a result, applications of SADA have extended into other disciplines that place strong emphasis on the spatial distribution of data. This paper provides an overview of the central functions of SADA and discusses how we addressed the problem of presenting complex and integrated models in a tractable manner. Information on SADA and a free download of the program can be found at http://www.tiem.utk.edu/~sada/.

PRESENTATION	Calculating Physicochemical Properties for Environmental Modeling Using Sparc	05/22/2007

CARREIRA, L. A., T. S. WHITESIDE, S. N. AYYAMPALAYAM, AND S. H. HILAL. Calculating Physicochemical Properties for Environmental Modeling Using Sparc. Presented at International Science Forum on Computational Toxicology, Research Triangle Park, NC, May 21 - 23, 2007.
Abstract:	Slide presentation for the International Science Forum on Computational Toxicology, May 21-23, 2007.

PRESENTATION	Mercury in the Environment	02/17/2007

LOUX, N. T. Mercury in the Environment. Presented at Georgia Science Teachers Association Conference, Athens, GA, February 15 - 17, 2007.
Abstract:	This presentation was a general overview of mercury in the environment presented to the Georgia Science Teachers Association Conference which was held in Athens, GA, in February 2007.

PRESENTATION	Issues in Simulating Elemental Mercury Air/Water Exchange and Aqueous Monomethylmercury Speciation	02/14/2007

LOUX, N. T. Issues in Simulating Elemental Mercury Air/Water Exchange and Aqueous Monomethylmercury Speciation. Presented at EPA Metals Fate and Transport Modeling Worksop, Denver, CO, February 13 - 15, 2007.
Abstract:	This presentation focuses on two areas relevant to assessing the global fate and bioavailability of mercury: elemental mercury air/water exchange and aqueous environmental monomethylmercury speciation.

PRESENTATION	Human Health and Ecological Risk Assessment With Spatial Analysis and Decision Assistance (Sada) Freeware	08/07/2007

PURUCKER, S. T. AND R. N. STEWART. Human Health and Ecological Risk Assessment With Spatial Analysis and Decision Assistance (Sada) Freeware. Presented at Office of Solid Waste and Emergency Response, Technology Innovation Program Internet Seminar, Washington, DC, August 07, 2007.
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 China: Emerging Environmental Contaminants and Current Issues	09/27/2007

RICHARDSON, S. D. Meeting in China: Emerging Environmental Contaminants and Current Issues. Presented at Seminars at Hong Kong University of Science & Technology; Chinese Academy of Science; and Beijing University, Beijing, CHINA, September 24 - 28, 2007.
Abstract:	Much has been achieved in the way of environmental protection over the last 30 years. However, as we learn more, new concerns arise (including potential adverse health effects, bioaccumulation, and widespread distribution). 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), pharmaceuticals, perfluorooctanoic acid (PFOA), polybrominated diphenyl ether (PBDE) flame retardants, 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. Concerns with PFOA and PBDEs include widespread global distribution in the blood of the general human population and in wildlife, as well as potential health effects, including cancer and developmental toxicity. Pharmaceuticals are of concern due to antibiotic resistance and potential endocrine disrupting effects. Some of the emerging contaminants (e.g., nitrosamines, PBDE flame retardants, and pesticide degradation products) are currently listed on the proposed Unregulated Contaminants Monitoring Rule (UCMR2), which requires EPA to select five or more contaminants every five years to consider for regulation. Other emerging contaminants are listed on the Contaminant Candidate List (CCL), which identifies drinking water contaminants that might be regulated by EPA at a future date, and other emerging contaminants are currently under consideration for the UCMR and the 3rd CCL. The status and health/environmental issues with these emerging environmental contaminants will be discussed, as well as analytical methods used to measure them.

PRESENTATION	Meeting in China: Chlorinated Vs. Chloraminated Drinking Water: Toxicity-Based Identification of Disinfection By-Products Using Esi-MS and Esi-MS/MS	09/24/2007

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 China: Chlorinated Vs. Chloraminated Drinking Water: Toxicity-Based Identification of Disinfection By-Products Using Esi-MS and Esi-MS/MS. Presented at Colloquium Spectroscopicum Internationale XXXV, Xiamen, CHINA, September 25 - 26, 2007.
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, and some cause cancer in laboratory animals. As a result, the U.S. Environmental Protection Agency (EPA) has regulated several DBPs. However, >500 DBPs have been reported in drinking water for which little or no occurrence and health data exist. In addition, there is almost no information on high molecular weight DBPs (> 1000 Da), which are indicated to comprise >50% of the total organic halide (TOX) from chlorinated drinking water. None of these high molecular weight halogenated by-products have ever been precisely identified, and there is no information on potential toxicity of this high molecular weight fraction. The goal of this research is to use 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 and 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.

PRESENTATION	Vapor Intrusion Challenges	08/09/2007

WEAVER, J. W. Vapor Intrusion Challenges. Presented at Micah's Mission Monthly Meeting, Danielsville, GA, August 09, 2007.
Abstract:	Slide presentation on vapor intrusion challenges.

PRESENTATION	Meeting in Czech Republic: Sada: A Freeware Decision Support Tool Integrating GIS, Sample Design, Spatial Modeling, and Risk Assessment	05/24/2007

STEWART, R. N., S. T. PURUCKER, AND G. E. POWERS. Meeting in Czech Republic: Sada: A Freeware Decision Support Tool Integrating GIS, Sample Design, Spatial Modeling, and Risk Assessment. Presented at ISESS 2007 Conference, Prague, CZECH REPUBLIC, May 22 - 25, 2007.
Abstract:	Spatial Analysis and Decision Assistance (SADA) is a Windows freeware program that incorporates tools from environmental assessment into an effective problem-solving environment. SADA was developed by the Institute for Environmental Modeling at the University of Tennessee and 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 began in the middle 1990s as a simple tool for integrating human health risk with spatial modeling tools. Since then, SADA has continued as an evolving freeware product targeted to individuals needing the integration or expansion of existing models into a spatial context. Because of the varied user base, SADA was engineered with an open and highly scaleable environment that in most cases allows additional functionality without an apparent increase in complexity. As a result, applications of SADA have extended into other disciplines that place strong emphasis on the spatial distribution of data. This paper provides an overview of the central functions of SADA and discusses how we addressed the problem of presenting complex and integrated models in a tractable manner. Information on SADA and a free download of the program can be found at http://www.tiem.utk.edu/~sada/.

PRESENTATION	Modeling the Effects of Climate and Land Use Change on Carbon and Trace Gas Budgets Over the Amazon Region Using Nasa Satellite Products	09/28/2007

POTTER, C., M. BUSTAMANTE, S. KLOSTER, V. GENOVESE, L. FERREIRA, A. HUERTE, R. COSME, R. NEMANI, AND R. G. ZEPP. Modeling the Effects of Climate and Land Use Change on Carbon and Trace Gas Budgets Over the Amazon Region Using Nasa Satellite Products. Presented at Large-Scale Biosphere-Atmosphere Eco Science Team Meeting and Synthesis Workshop, Salvador, BRAZIL, September 26 - 30, 2007.
Abstract:	As part of the LBA-ECO Phase III synthesis efforts for remote sensing and predictive modeling of Amazon carbon, water, and trace gas fluxes, we are evaluating results from the regional ecosystem model called NASA-CASA (Carnegie-Ames Stanford Approach). The NASA-CASA model has been formulated to run at monthly time intervals for the years 2000 to the present using NASA satellite data inputs from the MODIS and CERES sensors. Our preliminary results point to the importance of better understanding and mapping the influence of incident solar radiance, rainfall amounts, and land cover changes at the basin scale to reduce model uncertainties in relation to LBA tower flux records. For more information, go to http://geo.arc.nasa.gov/sge/casa/

PRESENTATION	Regional Emissions of Nitric Oxide (No) and Carbon Dioxide (Co2) in Agroecosystems in Central West Region, Brazil.	09/28/2007

FERNANDES, E., M. BUSTAMANTE, A. KOZOVITS, AND R. G. ZEPP. Regional Emissions of Nitric Oxide (No) and Carbon Dioxide (Co2) in Agroecosystems in Central West Region, Brazil. Presented at Large-Scale Biosphere-Atmosphere Eco Science Team Meeting and Synthesis Workshop, Salvador, BRAZIL, September 28 - 30, 2007.
Abstract:	The Central West Region in Brazil has been the focus of intense agricultural expansion since the 1970s and, nowadays, a large area of native cerrado has been converted to agricultural use. The expansion was accompanied by intensive use of fertilizer, irrigation and management practices. However, the consequences of these agricultural practices on NO and CO2 emissions from soil to atmosphere are still unclear. Here, we present estimates of regional emissions of NO and CO2 in a Latosol cultivated with corn, soybean, cotton and irrigated bean, under a no till system. The measurements were made from August, 2003 to August, 2005. NO and CO2 fluxes were measured before and after planting, after nitrogen fertilization, during the growing season and before and after harvesting. The regional emissions were estimated considering the area occupied by the crops and the cropping cycle (corn 173, soybeans 134, cotton 258 and irrigated beans 135 days). The field cotton had the highest N-NO emission per unit area (0.8 kg ha-1), followed by irrigated beans and corn (0.3 kg ha-1) and soybeans (0.2 kg ha-1). Per hectare, the field cotton and corn contributed 34.6 and 32.0 tons C-CO2, the irrigated beans 25,4 tons and the soybeans 19.4 tons C-CO2. Integrated over all cultivated fields, the highest soil emissions of NO and CO2 came from soybeans which emitted 4.6 Gt N-NO and 0.12 Tg C-CO2 from 22,854,000 ha, followed by corn with 3.7 Gt N-NO and 0.11 Tg C-CO2 from 12,297,000 ha, irrigated beans with 1.2 Gt N-NO and 0.03 Tg C-CO2 from 3,910,000 ha, and cotton with 0.9 Gt N-NO and 0.01 Tg C-CO2 from 1,152,000 ha. The results show that it is necessary for government policies to encourage management systems that enhance sustainability and that take into account the impacts of agricultural activities on soil emissions of NO and CO2.

PRESENTATION	Meeting in Charlotte, Nc: Methods for the Analysis of Priority DBPs in Ro-Concentrated Drinking Water	11/05/2007

BODIN, N., H. S. WEINBERG, S. W. KRASNER, S. D. RICHARDSON, J. G. PRESSMAN, T. F. SPETH, R. J. MILTNER, AND J. E. SIMMONS. Meeting in Charlotte, Nc: Methods for the Analysis of Priority DBPs in Ro-Concentrated Drinking Water. Presented at 2007 Water Quality Technology Conference, Charlotte, NC, November 04 - 08, 2007.
Abstract:	Slide presentation for the AWWA Water Quality Technology Conference, November 4-8, 2007.

PRESENTATION	Analyzing the Sausalito Outfall With Visual Plumes	08/30/2007

FRICK, W. E. AND P. J. ROBERTS. Analyzing the Sausalito Outfall With Visual Plumes. Presented at Visual Plumes Mixing Zone Modelling Course, Sacramento, CA, August 30 - 31, 2007.
Abstract:	Slide presentation for the Visual Plumes Mixing Zone Modelling Course, August 2007.

PRESENTATION	Ecological Endpoints in Watershed Management	10/23/2007

RASHLEIGH, B. Ecological Endpoints in Watershed Management. Presented at NATO CCMS Pilot Study 5th Workshop on Sustainable Use and Development of Watersheds for Human Security and Peace, Istanbul, TURKEY, October 22 - 26, 2007.
Abstract:	Slide presentation for the NATO CCMS Pilot Study 5 Workshop in Istanbul Turkey, October 2007.

PRESENTATION	An Open-Source Community Web Site to Support Ground-Water Model Testing	12/11/2007

KRAEMER, S. R., M. BAKKER, AND J. R. CRAIG. An Open-Source Community Web Site to Support Ground-Water Model Testing. Presented at 2007 AGU Fall Meeting, San Francisco, CA, December 10 - 14, 2007.
Abstract:	A community wiki wiki web site has been created as a resource to support ground-water model development and testing. The Groundwater Gourmet wiki is a repository for user supplied analytical and numerical recipes, how-to's, and examples. Members are encouraged to submit analytical solutions, including source code and documentation. A diversity of code snippets are sought in a variety of languages, including Fortran, C, C++, Matlab, Python. In the spirit of a wiki, all contributions may be edited and altered by other users, and open source licensing is promoted. Community accepted contributions are graduated into the library of analytic solutions and organized into either a Strack (Groundwater Mechanics, 1989) or Bruggeman (Analytical Solutions to Geohydrological Problems, 1999) classification. The examples section of the wiki are meant to include laboratory experiments (e.g., Hele Shaw), classical benchmark problems (e.g., Henry Problem), and controlled field experiments (e.g., Borden landfill and Cape Cod tracer tests).

PRESENTATION	Meeting in China: Emerging Disinfection By-Products and Current Issues	09/22/2007

RICHARDSON, S. D. Meeting in China: Emerging Disinfection By-Products and Current Issues. Presented at Seminars at Hong Kong University of Science & Technology and Beijing University, Hong Kong and Beijing, CHINA, September 22 - 29, 2007.
Abstract:	Slide presentation for seminars in China, September 2007.

PRESENTATION	Gasoline Composition, Ethers, Ethanol, and Lead Scavengers in 2007	09/19/2007

WEAVER, J. W. Gasoline Composition, Ethers, Ethanol, and Lead Scavengers in 2007. Presented at 18th Annual Alabama UST Assessment and Remediation Conference, Montgomery, AL, September 18 - 19, 2007.
Abstract:	Slide presentation presented at the 18th Annual Alabama UST Assessment and Remediation Conference, September 2007.

PRESENTATION	Metabolomics in Small Fish Toxicology and Other Environmental Applications	10/19/2007

COLLETTE, T. W. Metabolomics in Small Fish Toxicology and Other Environmental Applications. Presented at Fort Johnson Marine Science Seminar Series, Charleston, SC, October 19, 2007.
Abstract:	Although lagging behind applications targeted to human endpoints, metabolomics offers great potential in environmental applications, including ecotoxicology. Indeed, the advantages of metabolomics (relative to other 'omic techniques) may be more tangible in ecotoxicology because there is often not a sequenced genome available for ecologically relevant species. We are conducting metabolomics studies on small fish, such as the fathead minnow, that are used both as model organisms in ecotoxicology research, and in regulatory testing programs. Our goal is to use information from these studies to meet EPA's mission to protect ecosystems from potentially harmful effects of chemical pollutants. For example, as part of a project involving a large, interdisciplinary team of scientists from US government, academia, and industry, we are integrating transcriptomic, proteomic, and metabolomic data to describe endocrine disruption in the fathead minnow. We seek to understand how chemical exposures are linked through early molecular changes to whole-organism adverse outcomes and, ultimately, to changes in population status. To achieve this goal, a systems-based approach is being used to define toxicity pathways for model chemicals with well defined modes of action within the hypothalamic-pituitary-gonadal (HPG) axis of the fathead minnow. We will describe the unique role that metabolomics plays in this, and in other, important environmental applications.

PRESENTATION	What Is Visual Plumes?	10/09/2007

FRICK, W. E. What Is Visual Plumes? Presented at Visual Plumes Mixing Zone Modeling Course, Olympia, WA, October 09 - 11, 2007.
Abstract:	Course presented at the Washington State Department of Ecology, Olympia, WA, October 2007.

PRESENTATION	Iodo-Acid Disinfection By-Products in Drinking Water: Does LC/Esi-MS/MS Offer An Advantage Over Gc/Nci-Ms?	11/29/2007

RICHARDSON, S. D., F. FASANO, J. J. ELLINGTON, F. G. CRUMLEY, K. BUETTNER, J. J. EVANS, B. C. BLOUNT, L. K. SILVA, F. L. CARDINALI, M. J. PLEWA, E. D. WAGNER, G. W. LUTHER III, AND T. J. WAITE. Iodo-Acid Disinfection By-Products in Drinking Water: Does LC/Esi-MS/MS Offer An Advantage Over Gc/Nci-Ms? Presented at 20th Annual Tandem Mass Spectrometry Workshop, Lake Louise, AB, CANADA, November 28 - December 01, 2007.
Abstract:	As part of a recent Nationwide Disinfection By-Product (DBP) Occurrence Study, iodo-acids were identified for the first time as DBPs in drinking water disinfected with chloramines. The iodo-acids identified included iodoacetic acid, bromoiodoacetic acid, (E)-3-bromo-3-iodo-propenoic acid, (Z)-3-bromo-3-iodo-propenoic acid, and (E)-2-iodo-3-methylbutenedioic acid. There is concern because toxicity studies have revealed that iodoacetic acid is highly cytotoxic and genotoxic, with a genotoxicity potency 2X higher than bromoacetic acid, the most genotoxic of the regulated haloacetic acids. Also, many drinking water treatment plants in the United States have switched from chlorine to chloramines for treatment. New evidence indicates that the formation of iodinated DBPs will be higher in chloraminated drinking water than in chlorinated drinking water. As a result, we initiated an occurrence study of 23 plants in North America and developed a gas chromatography (GC)/negative chemical ionization (NCI) mass spectrometry (MS) method to measure the iodo-acids in drinking waters across the U.S. GC/NCI-MS was much more sensitive than traditional GC/electron ionization (EI)-MS, and the NCI-MS was ideal for these iodinated compounds, as the iodo-acids were much more sensitive than the corresponding bromo- and chloro-acids. Detection limits of low and sub-ng/L could be obtained using GC/NCI-MS when extracting 1 L of drinking water and derivatizing by methylation. However, recoveries were not in the desired 90-100% range, and it was evident that the derivatization efficiency was the primary reason for less than ideal recoveries. As a result, we investigated the possibility to measure these using liquid chromatography (LC)/electrospray ionization (ESI)-MS/MS so that derivatization would not be necessary, and possibly extraction would not be necessary. A comparison of LC/ESI-MS/MS results to those with GC/NCI-MS will be presented, along with data from the occurrence study and new toxicity results.

PRESENTATION	Statistical Techniques to Relate Landscape Measures to Instream Biota	10/17/2007

RASHLEIGH, B. AND M. J. CYTERSKI. Statistical Techniques to Relate Landscape Measures to Instream Biota. Presented at Workshop for Advanced Methods in GIS, Research Triangle Park, NC, October 17, 2007.
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 Gettysburg: Impacts of Regulation on U.S. Gasoline Composition	10/22/2007

WEAVER, J. W. AND L. R. EXUM. Meeting in Gettysburg: Impacts of Regulation on U.S. Gasoline Composition. Presented at EPA Region III States LUST Technical Workshop, Gettysburg, PA, October 22 - 24, 2007.
Abstract:	Poster presented at the EPA Region III States LUST Technical Workshop in October 2007.

PRESENTATION	Meeting in Gettysburg: Gasoline Composition in the U.S. (1976-2005)	10/22/2007

WEAVER, J. W., L. M. PRIETO, AND L. R. EXUM. Meeting in Gettysburg: Gasoline Composition in the U.S. (1976-2005). Presented at EPA Region III States LUST Technical Workshop, Gettysburg, PA, October 22 - 24, 2007.
Abstract:	Poster presented at the EPA Region III Lust Workshop, October 2007.

PRESENTATION	Meeting in Gettysburg: Integrating Modeling Into Plume Diving Assessment	10/22/2007

WEAVER, J. W. AND V. K. Gorokhovski. Meeting in Gettysburg: Integrating Modeling Into Plume Diving Assessment. Presented at EPA Region III States LUST Technical Workshop, Gettysburg, PA, October 22 - 24, 2007.
Abstract:	Poster presented at the EPA Region III States LUST Workshop in October 2007.

PRESENTATION	U.S. Gasoline Composition After the 2005 Energy Policy Act	10/22/2007

WEAVER, J. W. U.S. Gasoline Composition After the 2005 Energy Policy Act. Presented at EPA Region III States LUST Technical Workshop, Gettysburg, PA, October 22 - 24, 2007.
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	Human Ecosystem Interactions: the Case of Mercury	10/17/2007

MANGIS, D. R., C. D. KNIGHTES, AND D. A. VALLERO. Human Ecosystem Interactions: the Case of Mercury. Presented at 17th Annual Conference of the International Society of Exposure Analysis, Durham, NC, October 14 - 18, 2007.
Abstract:	Human and ecosystem exposure studies evaluate exposure of sensitive and vulnerable populations. We will discuss how ecosystem exposure modeling studies completed for input into the US Clean Air Mercury Rule (CAMR) to evaluate the response of aquatic ecosystems to changes in mercury deposition will be used to improve human exposure modeling for methylmercury. Results from the five freshwater case studies showed that most freshwater systems will achieve 90% of the benefits of the mercury emissions reductions as the result of CAMR in 2-3 decades. Some systems may respond faster (5-10 years), and watershed dominated systems will likely take 50 years or more to respond. Attenuation of methylmercury after load reductions are calculated for northern pike and yellow perch by size class to illustrate body burdens across species and size classes that are cost prohibitive to sample effectively. The time lag in ecosystem response has a major effect on the benefits of regulations and how quickly these benefits are translated into human health benefits. By coupling ecosystem process models developed to evaluate the impacts of mercury reductions on sensitive ecosystems with atmospheric source models, and human consumption models, we can improve our human exposure risk analyses of mercury control scenarios, and better evaluate the impacts of local mercury hotspots to ecosystems and local fish consumptive human populations. The next step is to take this to the coastal and oceanic systems to determine how much reduction of mercury is needed to protect coastal and ocean ecosystems, and humans, since most mercury exposure comes from ocean fish consumption.

PRESENTATION	Meeting in Atlanta: U.S. Gasoline Composition After the 2005 Energy Policy Act	11/15/2007

WEAVER, J. W. Meeting in Atlanta: U.S. Gasoline Composition After the 2005 Energy Policy Act. Presented at NEIWPCC Assessment of Remediation of Oxygenates and Other Fuel Components Meeting, Atlanta, GA, November 15 - 16, 2007.
Abstract:	Slide presentation for the New England Interstate Water Pollution Control Commission Meeting in Atlanta, GA, November 15-16, 2007.

PRESENTATION	Seminar in Canada: Emerging Environmental Contaminants and Current Issues	11/27/2007

RICHARDSON, S. D. Seminar in Canada: Emerging Environmental Contaminants and Current Issues. Presented at Seminar at Health Canada, Ottawa, ON, CANADA, November 27, 2007.
Abstract:	Presentation given in Canada on emerging environmental contaminants and current issues.

PRESENTATION	Geospatial Analysis of Pesticide Drift from Applications to Control Silverleaf Whiteflies on Tomato Farms	12/04/2007

JULIEN, R., S. L. BIRD, L. R. EXUM, AND L. M. PRIETO. Geospatial Analysis of Pesticide Drift from Applications to Control Silverleaf Whiteflies on Tomato Farms. Presented at Pestidrift Meeting, Quincy, FL, December 04, 2007.
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	Emerging Disinfection By-Products and Other Emerging Environmental Contaminants: What's New	12/03/2007

RICHARDSON, S. D. Emerging Disinfection By-Products and Other Emerging Environmental Contaminants: What's New. Presented at Seminar at Alberta Research Council, Edmonton, AB, CANADA, December 03, 2007.
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.

PUBLISHED REPORT	United States Meteorological Data Daily and Hourly Files to Support Predictive Exposure Modeling	05/16/2007

BURNS, L. A., L. A. SUAREZ, AND L. M. PRIETO. United States Meteorological Data Daily and Hourly Files to Support Predictive Exposure Modeling. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-07/053 (NTIS PB2007-110161), 2007.
Abstract:	ORD numerical models for pesticide exposure include a model of spray drift (AgDisp), a cropland pesticide persistence model (PRZM), a surface water exposure model (EXAMS), and a model of fish bioaccumulation (BASS). A unified climatological database for these models has been assembled from several National Weather Service (NWS) datasets, including Solar and Meteorological Surface Observation Network (SAMSON) data for 1961-1990 (versions 1.0 and 1.1), combined with NWS precipitation and evaporation data. Together these NWS products provide coordinated access to solar radiation, sky cover, temperature, relative humidity, station atmospheric pressure, wind direction and speed, and precipitation. The resulting hourly and daily weather parameters provide a unified dataset for use in coordinated exposure modeling. The data files, which include some derived data of use to exposure modeling (e.g., short-grass crop standard evapotranspiration ET0) are publicly available (gratis) on EPA's Center for Exposure Assessment Modeling (CEAM) web site at http://www.epa.gov/ceampubl/tools/metdata/index.htm. By using observational data for models, trace-matching Monte Carlo simulation studies can transmit the effects of environmental variability directly to exposure metrics, by-passing issues of correlation (covariance) among external driving forces.

PUBLISHED REPORT	A Catalog of Ground Water Flow Solutions for Plume Diving Calculations	10/04/2007

GOROKHOVSKI, V. M. AND J. W. WEAVER. A Catalog of Ground Water Flow Solutions for Plume Diving Calculations. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-07/122, 2007.
Abstract:	This report focuses on the problem of diving plumes, a term which generally refers to plumes that go deeper into aquifers with distances from their sources. This document presents the mathematical basis of software for real-time development and refinement of site conceptual models. The emphasis in the work is on evaluation of ground water flow patterns and the proper placement of vertical sample intervals. Lack of consideration of plume diving could result in underestimation of the extent of contamination at these sites.

PUBLISHED REPORT	Evaluation of Selected Dna-Based Technology in Impaired Watersheds Impacted By Fecal Contamination from Diverse Sources	12/10/2007

MOLINA, M. Evaluation of Selected Dna-Based Technology in Impaired Watersheds Impacted By Fecal Contamination from Diverse Sources. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-07/123 (NTIS PB2008-107359), 2007.
Abstract:	Fecal pollution of surface waters is a top reason for impairment, as listed by the U.S. Environmental Protection Agency’s report on the quality of the Nation's waters. To be able to develop and implement TMDLs in impaired aquatic resources, it is imperative to determine the sources of the contamination. One tool used to determine the sources of bacterial fecal contamination is to apply a microbial source tracking approach to the system of interest. Microbial source tracking (MST) approaches are based on the assumption that specific strains of bacteria, genetic fingerprints, or DNA-based markers are associated with specific host species. Because accurate source identification of fecal contamination is essential in MST, more sensitive, selective and reliable molecular markers are required. The two types of genotypic methods that have been applied widely in a variety of environments can be classified as library-independent (LI) and library-dependent (LD). For both types of methods, the temporal and spatial stability of selected genotypes are aspects that need to be evaluated and are often times missing when applying MST to environmental samples. LD-MST methods require the development of large databases comprised of source specific isolates. Once a source specific fingerprint has been identified, the temporal and spatial variability of the particular genotype still needs to be validated. LI-MST is based on the application of culture-independent methods such as amplification of DNA from environmental samples using 16S rDNA markers in combination with polymerase chain reaction (PCR). However, cross-reactivity of some of the 16S rDNA markers used in field studies has prompted the development of alternative PCR assays using metagenomic markers specific for bovine feces. In this study we report on the comparison of selected LD and LI methodologies, their usability as rapid reliable methods for developing and applying markers to various environmental scenarios, and the stability of these markers under spatial and temporal considerations. From our results we concluded that library production is highly time and resource consuming. Its application is probably appropriate in very specific scenarios where discrimination among few selective sources is necessary. In contrast, application of DNA, PCR-based markers produced fairly rapid results and has the capability to screen multiple scenarios in a short period of time. Once stability and cross-amplification aspects have been addressed, it can be a highly efficacious approach to determine sources of contamination in a variety of scenarios.

		ORD Home \| Search EPA \| Search NERL \| Search EIMS \| Contacts \| Help


		EPA Home \| Privacy and Security Notice \| Contact Us Last Updated on Tuesday, October 23, 2007 URL: http://cfpub.epa.gov/ordpubs/nerlpubs/nerlpubs_erd_2007.cfm