Skip common site navigation and headers
United States Environmental Protection Agency
Exposure Research
Begin Hierarchical Links EPA Home > Research & Development > Exposure Research > Publications/Presentations > End Hierarchical Links

 

Ecosystems Research Division Publications: 2005

spacer
spacer

This page lists publication titles, citations and abstracts produced by NERL's Ecosystems Research Division for the year 2005, organized by Publication Type. Your search has returned 180 Matching Entries.

See also Ecosystems Research Division citations with abstracts: 1999,  2000,  2001,  2002,  2003,  2004,  2005,  2006,  2007,  2008,  2009

Technical Information Manager: Janice Sims - (706) 355-8011 or sims.janice@epa.gov

spacer
Presented/Published
BOOK CHAPTER Nitrate and Nitrous Oxide Concentrations in Small Streams of the Georgia Piedmont 06/01/2005
Burke Jr., R A. AND J. Molinero. Nitrate and Nitrous Oxide Concentrations in Small Streams of the Georgia Piedmont. Chapter 3.4, Russo, R.C. (ed.), NATO/CCMS Pilot Study: Modeling Nutrient Loads and Response in River and Estuary Systems. NATO - CCMS, Brussels, Belgium, 79-89, (2005).
Abstract: We are measuring dissolved nitrate and nitrous oxide concentrations and related parameters in 17 headwater streams in the South Fork Broad River, Georgia watershed on a monthly basis. The selected small streams drain watersheds dominated by forest, pasture, residential, or mixed land uses. Mean stream nitrate concentrations are lowest in forested watersheds (0.09 to 0.20 mg N L(-1)) and somewhat higher in streams draining agricultural (0.39 to 0.99 mg N L(-1)) and mixed (0.39 to 1.08 mg N L(-1)) land-use watersheds. One of the residential watersheds showed an appreciably higher mean stream nitrate concentration (1.79 mg N L(-1)) than any of the other watersheds but nitrate levels in the other residential watersheds were similar to those in watersheds with other land uses. Nitrous oxide concentrations vary widely from about 10 nM (approximate atmospheric equilibrium concentration) to greater than 80 nM among the streams. Overall, the streams draining watersheds dominated by residential and agricultural land use have significantly higher dissolved nitrous oxide concentrations than those draining forested watersheds. Our results suggest that small streams could be a significant conduit of nitrous oxide from the terrestrial environment to the atmosphere in some watersheds.

DATA Johnson and Ettinger (1991) Vapor Intrusion Model With Sub-Slab Concentration 10/31/2005
TILLMAN, F. AND J. W. WEAVER. Johnson and Ettinger (1991) Vapor Intrusion Model With Sub-Slab Concentration. U.S. Environmental Protection Agency, Washington, DC, EPA/600/C-06/002, 2005.
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. Vapor intrusion is a particularly difficult pathway to assess, as challenges exist in delineating subsurface contributions to measured indoor air concentrations as well as in adequate characterization of subsurface parameters necessary to calibrate a predictive flow and transport model. Often, a screening-level model is 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. A popular screening-level algorithm currently in wide use in the United States and Canada for making such determinations is the Johnson and Ettinger (J&E) model. The form of the J&E model most widely used has as an output an attenuation factor defined as the ratio of the indoor air contaminant concentration to that of the vapor source concentration. This attenuation coefficient is dimensionless and is often used to back-calculate cleanup goals based on indoor air contaminant measurements and acceptable risk levels, or to predict potential indoor air contaminant exposure and risk based on measured source concentrations. However, use of the attenuation factor does not allow for the direct computation of sub-slab vapor concentration. This Microsoft Excel workbook provides a means to calculate sub-slab vapor concentrations based on user-input values for subsurface and building parameters. Use of this model allows practitioners to compare predicted sub-slab contaminant concentrations with field-measured sub-slab data.

DATA Indoor Air Concentration Unit Conversions 07/28/2005
TILLMAN, F. AND J. W. WEAVER. Indoor Air Concentration Unit Conversions. U.S. Environmental Protection Agency, Washington, DC, EPA/600/C-05/007, 2005.
Abstract: Migration of volatile chemicals from the subsurface into overlying buildings is called vapor intrusion (VI). Volatile organic chemicals in contaminated soils or groundwater can emit vapors, which can migrate through subsurface soils and may enter the indoor air of overlying buildings. In extreme cases, the vapors may accumulate in dwellings to levels that pose near-term safety hazards, such as explosion. Typically, however, vapor concentrations are present at low levels, to which long-term exposure may pose increased risk for chronic health effects. In evaluating indoor air concentrations of carcinogenic or toxic compounds, some confusion exists over the various units in use. Common units of indoor air measurements include micrograms (or milligrams) per meter-cubed, micrograms (or milligrams) per liter, parts-per-billion-volume [ppbV] and parts-per-million-volume [ppmV], as well as percent [%]. The confusion arises because parts-per-billion (or million)-volume used in gas measurements is based on volume-to-volume ratio and is NOT the same as part-per-billion (or million) used in aqueous measurements that is based on a mass-per-mass ratio. Thus, micrograms per liter in gas systems IS NOT equal to [ppbV], nor is milligrams per liter in gas systems equal to [ppmV]. Each of these conversions is dependent upon the molecular weight of the contaminant and the temperature and pressure of the system. This on-line calculator (http://www.epa.gov/athens/learn2model/part-two/onsite/ia_unit_conversion.htm) permits conversions between all common units of indoor air concentration micrograms per liter, milligrams per liter, micrograms per meter-cubed, milligrams per meter-cubed, [ppmV], [ppbV] and percent [%] based on user inputs of contaminant type (with automatic look-up of molecular weight), indoor temperature and pressure.

DATA On-Line Calculator: Johnson Ettinger Vapor Intrusion Model 01/21/2005
TILLMAN, F. AND J. W. WEAVER. On-Line Calculator: Johnson Ettinger Vapor Intrusion Model. U.S. Environmental Protection Agency, Washington, DC, EPA/600/C-06/005, 2005.
Abstract: On-Site was developed to provide modelers and model reviewers with prepackaged tools ("calculators") for performing site assessment calculations. The philosophy behind OnSite is that the convenience of the prepackaged calculators helps provide consistency for simple calculations, and access to methods and data that are not commonly available. This on-line calculator implements the Johnson and Ettinger (J&E) (Johnson and Ettinger, 1991) simplified model to evaluate the vapor intrusion pathway into buildings. This J&E model replicates the implementation that the US EPA Office of Solid Waste and Emergency Response (OSWER) used in developing its draft vapor intrusion guidance, but includes a number of enhancements that are facilitated by web implementation: temperature dependence of Henry's Law Constants and gaseous diffusivities, automatic sensitivity analysis of certain parameters, and others described on the background page.

EXTRAMURAL DOCUMENT Partition Coefficients for Metals in Surface Water, Soil, and Waste 07/25/2005
ALLISON, J. D. AND T. L. ALLISON. Partition Coefficients for Metals in Surface Water, Soil, and Waste. U.S. Environmental Protection Agency, Washington, DC, 2005.
Abstract: This report presents metal partition coefficients for the surface water pathway and for the source model used in the Multimedia, Multi-pathway, Multi-receptor Exposure and Risk Assessment (3MRA) technology under development by the U.S. Environmental Protection Agency. Partition coefficients values are presented for partitioning between soil and water; partitioning between the suspended sediment load and the water in streams, rivers, and lakes; partitioning between riverine or lacustrine sediment and its porewater; and partitioning between dissolved organic carbon (DOC) and the inorganic solution species in the water of streams, rivers, and lakes.

EXTRAMURAL DOCUMENT Geochemistry and Characteristics of Nitrogen Transport at a Confined Animal Feeding Operation in a Coastal Plain Agricultural Watershed, and Implications for Nutrient Loading in the Neuse River Basin, North Carolina, 1999-2002 03/18/2005
SPRUILL, T. B., A. J. TESORIERO, H. E. MEW, JR, K. M. FARRELL, S. L. HARDEN, A. B. COLOSIMO, AND S. R. KRAEMER. Geochemistry and Characteristics of Nitrogen Transport at a Confined Animal Feeding Operation in a Coastal Plain Agricultural Watershed, and Implications for Nutrient Loading in the Neuse River Basin, North Carolina, 1999-2002. U.S. Geological Survey, Reston, VA, 2005.
Abstract: Chemical, geologic, hydrologic, and age-dating information collected between 1999 and 2002 were used to examine the transport of contaminants, primarily nitrogen, in ground water and the pathways to surface water in a coastal plain setting in North Carolina. Data were collected from more than 35 wells and 4 surface-water sampling sites located in a 0.59 square-mile basin to examine detailed hydrogeology and geochemical processes affecting nutrient fate and transport.

JOURNAL 1h-Nmr Metabonomics Analysis of Sera Differentiates Between Mammary Tumor-Bearing Mice and Healthy Controls 10/18/2005
WHITEHEAD, T. L., B. MONZAVI-KARBASSI, AND T. KIEBER-EMMONS. 1h-Nmr Metabonomics Analysis of Sera Differentiates Between Mammary Tumor-Bearing Mice and Healthy Controls. Metabolomics. Plenum Press, New York, NY, 1(3):230-237, (2005).
Abstract: Global analysis of 1H-NMR spectra of serum is an appealing approach for the rapid detection of cancer. To evaluate the usefulness of this method in distinguishing between mammary tumor-bearing mice and healthy controls, we conducted 1H-NMR metabonomic analyses on serum samples obtained from the following: 10 mice inoculated with a highly-metastatic mammary carcinoma cell line, 10 mice inoculated with a "normally" metastatic mammary carcinoma cell line, and 10 healthy controls. Following standard spectral processing and subsequent data reduction, we applied unsupervised Principal Component Analysis (PCA) to determine if unique metabolic fingerprints for different categories of metastatic breast cancer in serum exist. The PCA method correctly separated sera of tumor-bearing mice from that of normal healthy controls, as shown using the scores plot which indicated that sera classes from tumor-bearing mice did not share multivariate space with that from healthy controls. In addition, this technique was capable of distinguishing between classes of varying metastatic ability in this system. Metabolites apparently responsible for separation between diseased and healthy mice include lactate, taurine, choline, and sugar moieties. Results of this study suggest that 1H-NMR spectra of mouse serum analyzed using PCA statistical methods indicate separation of tumor-bearing mice from healthy normal controls, justifying further study of the use of 1H-NMR metabonomics for cancer detection in serum.

JOURNAL New Disinfection By-Product Issues: Emerging Dbp's and Alternative Routes of Exposure 10/01/2005
RICHARDSON, S. D. New Disinfection By-Product Issues: Emerging Dbp's and Alternative Routes of Exposure. GLOBAL NEST: the International Journal. Global Network for Environmental Science and Technology, Athens, Greece, 7(1):43-60, (2005).
Abstract: This paper discusses current issues with drinking water disinfection by-products (DBPs), which include emerging (unregulated) DBPs that can be formed at greater levels with alternative disinfectants (as compared to chlorine) and routes of human exposure (which include inhalation and dermal exposure studies, in addition to ingestion). Of the alternative disinfectants, chloramination appears to increase the formation of iodo-acids, iodo-THMs, and NDMA and other nitrosamines, relative to chlorine. Preozonation appears to increase the formation of halonitromethanes.

JOURNAL Variations in the Spectral Properties of Freshwater and Estuarine Cdom Caused By Partitioning Onto River and Estuarine Sediments 10/01/2005
SHANK, G. C., R. G. ZEPP, R. F. WHITEHEAD, AND M. A. MORAN. Variations in the Spectral Properties of Freshwater and Estuarine Cdom Caused By Partitioning Onto River and Estuarine Sediments. ESTUARINE, COASTAL AND SHELF SCIENCE. Elsevier Science Ltd, New York, NY, 65(1/2):289-301, (2005).
Abstract: The optical properties and geochemical cycling of chromophoric dissolved organic matter (CDOM) are altered by its sorption to freshwater and estuarine sediments. Measured partition coefficients (Kp) of Satilla River (Georgia) and Cape Fear River estuary (North Carolina) CDOM ranged from 19 to 233 L kg-1 when model freshwater and organic-rich estuarine sediments were added to solution (concentrations of 0.1, 1, or 10 g L-1), with the largest Kp values measured in solutions with the lowest sediment concentrations.

JOURNAL An Individual-Based Simulation Model for Mottled Sculpin (Cottus Bairdi) in a Southern Appalachian Stream 09/25/2005
RASHLEIGH, B. AND G. D. GROSSMAN. An Individual-Based Simulation Model for Mottled Sculpin (Cottus Bairdi) in a Southern Appalachian Stream. ECOLOGICAL MODELLING. Elsevier Science BV, Amsterdam, Netherlands, 187(2-3):247-258, (2005).
Abstract: We describe and analyze a spatially explicit, individual-based model for the local population dynamics of mottled sculpin (Cottus bairdi). The model simulated daily growth, mortality, movement and spawning of individuals within a reach of stream. Juvenile and adult growth was based on consumption bioenergetics of benthic macroinvertebrate prey; benthic macroinvertebrate densities were a function of flow, season, and habitat quality. We based mortality rates of individual sculpin on their condition. Fish movement was determined by a growth maximization rule. We adjusted selected parameters to calibrate the model for a sculpin population in a southern Appalachian stream, in terms of adult and juvenile abundance and mean adult weight and length. Sensitivity and correlation analysis of the calibrated model suggested that this population was regulated by overwinter density-dependence among juveniles and adults.

JOURNAL Evaluating Predictive Errors of a Complex Environmental Model Using a General Linear Model and Least Square Means 08/25/2005
KNIGHTES, C. D. AND M. J. CYTERSKI. Evaluating Predictive Errors of a Complex Environmental Model Using a General Linear Model and Least Square Means. ECOLOGICAL MODELLING. Elsevier Science BV, Amsterdam, Netherlands, 186(3):366-374, (2005).
Abstract: A General Linear Model (GLM) was used to evaluate the deviation of predicted values from expected values for a complex environmental model. For this demonstration, we used the default level interface of the Regional Mercury Cycling Model (R-MCM) to simulate epilimnetic total mercury concentrations in Vermont and New Hampshire lakes based on data gathered through the EPAs Regional Environmental Monitoring and Assessment Program (REMAP).

JOURNAL Photochemical Mineralization of Dissolved Organic Nitrogen to Ammonium in the Baltic Sea 08/19/2005
VAHATALO, A. V. AND R. G. ZEPP. Photochemical Mineralization of Dissolved Organic Nitrogen to Ammonium in the Baltic Sea. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 39(18):6985-6992, (2005).
Abstract: Solar radiation-induced photochemistry can be considered as a new source of nutrients when photochemical reactions release bioavailable nitrogen from biologically non-reactive dissolved organic nitrogen (DON). Pretreatments of Baltic Sea waters in the dark indicated that >72% of DON was recalcitrant to biological mineralization. The results of this study indicate that the rate of photoammonification approximately equals and periodically exceeds the rate of atmospheric deposition of reactive inorganic nitrogen to the northern Baltic Sea. For these stratified surface waters beyond riverine input of labile nitrogen, photoammonification can periodically be the largest source of new bioavailable nitrogen.

JOURNAL Analysis of Disinfection By-Products in Drinking Water By LC-MS and Related MS Techniques 08/01/2005
ZWIENER, C. AND S. D. RICHARDSON. Analysis of Disinfection By-Products in Drinking Water By LC-MS and Related MS Techniques. TRENDS IN ANALYTICAL CHEMISTRY. Elsevier Science Ltd, New York, NY, 24(7):613-621, (2005).
Abstract: This review covers recent applications of LC/MS and other related techniques such as flow injection-atmospheric pressure chemical ionization and electrospray ionization-MS, high-field asymmetric waveform ion mobility spectrometry-electrospray ionization-MS, membrane introduction mass spectrometry, and ion chromatography-electrospray ionization-MS for measuring known DBPs and exploring the nature of previously uncharacterized DBPs.

JOURNAL Investigating Uncertainty and Sensitivity in Integrated, Multimedia Environmental Models: Tools for Frames-3mra 08/01/2005
Babendreier, J E. AND K. Castleton. Investigating Uncertainty and Sensitivity in Integrated, Multimedia Environmental Models: Tools for Frames-3mra. ENVIRONMENTAL MODELLING AND SOFTWARE 20(8):1043-1055, (2005).
Abstract: Elucidating uncertainty and sensitivity structures in environmental models can be a difficult task, even for low-order, single-medium constructs driven by a unique set of site-specific data. Quantitative assessment of integrated, multimedia models that simulate hundreds of sites, spanning multiple geographical and ecological regions, will ultimately require a comparative approach using several techniques, coupled with sufficient computational power. The Framework for Risk Analysis in Multimedia Environmental Systems - Multimedia, Multipathway, and Multireceptor Risk Assessment (FRAMES-3MRA) is an important software model being developed by the United States Environmental Protection Agency for use in risk assessment of hazardous waste management facilities. The 3MRA modeling system includes a set of 17 science modules that collectively simulate release, fate and transport, exposure, and risk associated with ha zardous contaminants disposed of in land-based waste management units (WMU). The 3MRA model encompasses 966 multi-dimensional input variables, over 185 of which are explicitly stochastic. Design of SuperMUSE, a 215 GHz PC-based, Windows-based Supercomputer for Model Uncertainty and Sensitivity Evaluation is described. Developed for 3MRA and extendable to other computermodels, an accompanying platform-independent, Java-based parallel processing software toolset is also discussed. For 3MRA, comparison of stand-alone PC versus SuperMUSE simulation executions showed a parallel computing overhead of only 0.57 seconds/simulation, a relative cost increase of 0.7% over average model runtime. Parallel computing software tools represent a critical aspect of exploiting the capabilities of such modeling systems. The Java toolset developed here readily handled machine and job management tasks over the Windows cluster, and is currently capable of completing over 3 million 3MRA model simulations per month on SuperMUSE. Preliminary work is reported for an example uncertainty analysis of Benzene disposal that describes the relative importance of various exposure pathways in driving risk levels for ecological receptors and human health. Incorporating landfills, waste piles, aerated tanks, surface impoundments, and land application units, the site-based data used in the analysis included 201 facilities across the United States representing 419 site-WMU combinations.

JOURNAL Nitrate Variability Along the Oregon Coast: Estuarine-Coastal Exchange 08/01/2005
SIGLEO, A. C., C. W. MORDY, P. STABENO, AND W. E. FRICK. Nitrate Variability Along the Oregon Coast: Estuarine-Coastal Exchange. ESTUARINE, COASTAL AND SHELF SCIENCE. Elsevier Science Ltd, London, Uk, 64(2-3):211-222, (2005).
Abstract: Coastal upwelling along the Eastern Pacific provides a major source of nutrients to nearby bays and estuaries during the summer months. To quantify the coastal ocean nitrogen input to Yaquina Bay, Oregon, nitrate concentrations were measured hourly from a moored sensor during summer upwelling in August 2000 outside the jetties to the estuary.

JOURNAL Gene Expression Changes in Arabidopsis Thaliana Seedling Roots Exposed to the Munition Hexahydro-1,3,5-Trinitro-1,3,5-Triazine 07/14/2005
EKMAN, D. R., N. L. WOLFE, AND J. F. DEAN. Gene Expression Changes in Arabidopsis Thaliana Seedling Roots Exposed to the Munition Hexahydro-1,3,5-Trinitro-1,3,5-Triazine. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 39(16):6313-6320, (2005).
Abstract: Arabidopsis thaliana root transcriptome responses to the munition, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), were assessed using serial analysis of gene expression (SAGE). Comparison of the transcriptional profile for the RDX response to a profile previously described for Arabidopsis roots exposed to trinitrotoluene (TNT) revealed significant differences in the inferred gene expression patterns. This suggests that Arabidopsis employs drastically different mechanisms for coping with these two compounds.

JOURNAL Application of Electrophoresis to Study the Enantioselective Transformation of Five Chiral Pesticides in Aerobic Soil Slurries 07/06/2005
JARMAN, J. L., W. J. JONES, L. A. HOWELL, AND A. W. GARRISON. Application of Electrophoresis to Study the Enantioselective Transformation of Five Chiral Pesticides in Aerobic Soil Slurries. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY. American Chemical Society, Washington, DC, 53(16):6175-6182, (2005).
Abstract: The enantiomers of five chiral pesticides of environmental interest, metalaxyl, imazaquin, fonofos (dyfonate), ruelene (cruformate) and dichlorprop, were separated analytically using capillary electrophoresis (CE) with cyclodextrin chiral selectors. CE is shown to be a simple, efficient and inexpensive way to follow the transformation of chiral pesticides in laboratory microcosms where concentrations can be made high enough (25-50 mg/L initial racemate concentration) for detection of residual parent enantiomers during most of the process.

JOURNAL Comparison of Highly-Fluorinated Chloroformates as Direct Aqueous Sample Derivatizing Agents for Hydrophilic Analytes and Drinking Water Disinfection By-Products 06/30/2005
VINCENTI, M., S. BIAZZI, N. GHIGLIONE, M. C. VALSANIA, AND S. D. RICHARDSON. Comparison of Highly-Fluorinated Chloroformates as Direct Aqueous Sample Derivatizing Agents for Hydrophilic Analytes and Drinking Water Disinfection By-Products. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY. Elsevier Science Ltd, New York, NY, 16(6):803-813, (2005).
Abstract: Four highly-fluorinated alkyl and aryl chloroformates, including 2,2,3,3,4,4,5,5-octafluoro-1-pentyl chloroformate (OFPCF), 2,3,4,5,6-pentafluorobenzyl chloroformate (PFBCF), 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octyl chloroformate (TDFOCF) and 2-(2,3,4,5,6-pentafluorophenoxy)-ethyl chloroformate (PFPECF), were synthesized and tested as reagents for the direct water derivatization of polar and hydrophilic analytes. The goal of this research was to develop an optimal derivatizing agent to aid in the identification of highly polar ozonation drinking water disinfection by-products (DBPs) that are believed to be missed with current analytical procedures.

JOURNAL Water Analysis: Emerging Contaminants and Current Issues, 2005 Review 06/15/2005
RICHARDSON, S. D. AND T. A. TERNES. Water Analysis: Emerging Contaminants and Current Issues, 2005 Review. Analytical Chemistry. American Chemical Society, Washington, DC, 77(12):3807-3838, (2005).
Abstract: This biennial review covers developments in Water Analysis over the period of 2003-2004. A few significant references that appeared between January and February 2005 are also included. Analytical Chemistry's current policy is to limit reviews to include 100-200 significant references and to mainly focus on new trends. As a result, as was done in the previous 2003 Water Analysis review, this 2005 review will limit its focus to new, emerging contaminants and environmental issues that are driving most of the current research. Even with a more narrow focus, only a small fraction of the quality research publications could be discussed. Thus, this review will not be comprehensive, but will highlight new areas and discuss representative papers in the new areas of focus.

JOURNAL Dispersant Effectiveness on Three Oils Under Various Simulated Environmental Conditions 05/30/2005
CHANDRASEKAR, S., G. A. SORIAL, AND J. W. WEAVER. Dispersant Effectiveness on Three Oils Under Various Simulated Environmental Conditions. ENVIRONMENTAL ENGINEERING SCIENCE. Mary Ann Liebert, Inc., Larchmont, NY, 22(3):324-336, (2005).
Abstract: The complexity of chemical and physical interactions between spilled oils, dispersants and the sea, necessitates an empirical approach for describing the interaction between the dispersant and oil slick which may provide a guide to dispersant effects on oil slicks. Recently, US EPA developed an improved laboratory dispersant testing protocol, called the baffled flask test. Use of this protocol was the basis for the experiments conducted in this study. A factorial experimental design was conducted in order to determine which of the factors temperature, oil type, oil weathering, dispersant type, and rotation speed of the shaker are related to the effectiveness of a dispersant used in oil remediation. Three oils were chosen to represent light refined oil (Number 2 Fuel Oil 2FO), light crude oil (South Louisiana Crude Oil (SLC)) and medium crude oil (Prudhoe Bay Crude Oil (PBC)). Statistical analyses of the experimental data performed separately for the three oils revealed that certain two-way interactions exist among the factors. For SLC, temperature and mixing energy were significant factors, for PBC, temperature, mixing energy and weathering were significant and for 2FO, only temperature was a significant factor. Empirical relationships between the amount of oil dispersed and the variables studied were developed.

JOURNAL Modeling Mercury Fluxes and Concentrations in a Georgia Watershed Receiving Atmospheric Deposition Load from Direct and Indirect Sources 05/15/2005
Ambrose Jr., R B., I. X. Tsiros, AND T A. Wool. Modeling Mercury Fluxes and Concentrations in a Georgia Watershed Receiving Atmospheric Deposition Load from Direct and Indirect Sources. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION 55(5):547-558, (2005).
Abstract: This paper presents a modeling analysis of airborne mercury deposited onto the Ochlockonee River watershed located in Georgia, USA. Atmospheric deposition monitoring and source attribution data were used along with simulation models to calculate mercury build-up in the subwatershed soils, its subsequent runoff loading and delivery through the tributaries, and its ultimate fate in the mainstem river. The terrestrial model calculated annual watershed yields for total mercury ranging from 0.7 to 1.1 micrograms/m2. Results suggest that about 2/3 of the atmospherically deposited mercury to the watershed is returned to the atmosphere, 10% is delivered to the river, and the rest is retained in the watershed. A check of the aquatic model results against survey data showed a reasonable agreement. Comparing observed and simulated total and methylmercury concentrations gave RMSE values of 0.26 ng/l and 0.10 ng/l, respectively, in the water column, and 5.9 ng/g and 1.0 ng/g, respectively, in the upper sediment layer. Sensitivity analysis results imply that mercury in the Ochlockonee River is dominated by watershed runoff inputs and not by direct atmospheric deposition, and that methylmercury concentrations in the river are mainly determined by net methylation rates in the watershed, presumably in wetted soils and in the wetlands feeding the river.

JOURNAL Environmental Effects of Ozone Depletion and Its Interactions With Climate Change: Progress Report 2004 02/15/2005
ZEPP, R. G., T. V. CALLAGHAN, AND D. J. ERICKSON. Environmental Effects of Ozone Depletion and Its Interactions With Climate Change: Progress Report 2004. PHOTOCHEMICAL AND PHOTOBIOLOGICAL SCIENCES. Royal Society of Chemistry, Cambridge, Uk, 4(2):177-184, (2005).
Abstract: The measures needed for the protection of the Earth's ozone layer are decided regularly by the Parties to the Montreal Protocol. This progress report is the 2004 update by the Environmental Effects Assessment Panel.

JOURNAL Purification and Partial Characterization of An Acid Phosphatase from Spirodela Oligorrhiza and Its Affinity for Selected Organophosphate Pesticides 01/12/2005
Hoehamer, C. F., C S. Mazur, AND N L. Wolfe. Purification and Partial Characterization of An Acid Phosphatase from Spirodela Oligorrhiza and Its Affinity for Selected Organophosphate Pesticides. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 53(1):90-97, (2005).
Abstract: An acid phosphatase from the aquatic plant Spirodela oligorrhiza (duckweed) was isolated by fast protein liquid chromatography (FPLC) and partially characterized. The enzyme was purified 1871-fold with a total yield of 40%. SDS-PAGE electrophoresis of the pure acid phosphatase resolved a single protein band that migrated to approximately 60-kD. Nondenaturing SDS-PAGE electrophoresis revealed a single protein band around 120-kD after staining with Coomassie Brilliant blue. Quantitative gel filtration chromatography estimated a native molecular mass of this enzyme to be 120-kD. Thus, this acid phosphatase likely functions as a homodimer, consisting of two similar 60-kD subunits. An electrophoretic technique using the flourogenic substrate 4-methylumbelliferylphosphate enabled visualization of an acid phosphatase activity that corresponded to the protein band at 120-kD on a non-denaturing PAGE gel. It was determined that the acid phosphatase had a pH optimum of 6.0 at 25 degrees C. The enzyme activity appeared to be stable over a broad range of temperatures (10-40 degrees C) and in the presence of the metals Zn+2 , Mn+2 , and Mg+2 as well as the chelating agents EDTA and EGTA. It was shown that this acid phosphatase could hydrolyze a variety of physiological organophosphate compounds including, beta-glycerophosphate, phosphoserine, adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monphosphate (AMP) and pyrophosphate. Furthermore, analysis using capillary electrophoresis demonstrated this hydrolytic enzyme could transform a wide array of organophosphate pesticides including S-2-ethylthioethyl O, O-dimethyl phosphorothioate (demeton-S-methyl); S-1, 2-bis(ethoxycarbonyl)ethyl O, O-dimethyl phosphorodithioate (Malathion); O, O-dimethyl O-4-nitrophenyl (paraoxon); O, O, O, O-tetraethyl dithiopyrophosphate (sulfatep); O-2-chloro-4-nitrophenyl O, O-dimethyl phosphorothioate (dicapthon); and 2, 2-dichlorovinyl dimethyl phosphate (dichlorvos).

JOURNAL Workshop Report: Computational Toxicology: Framework, Partnerships, and Program Development, September 29-30, 2003, Research Triangle Park, North Carolina 01/01/2005
KAVLOCK, R. J., G. T. ANKLEY, T. W. COLLETTE, E. Z. FRANCIS, K. A. HAMMERSTROM, J. R. FOWLE, H. A. TILSON, G. P. TOTH, P. K. SCHMIEDER, G. D. VEITH, E. J. WEBER, D. C. WOLF, AND D. M. YOUNG. Workshop Report: Computational Toxicology: Framework, Partnerships, and Program Development, September 29-30, 2003, Research Triangle Park, North Carolina. REPRODUCTIVE TOXICOLOGY. Elsevier Science Ltd, New York, NY, 19(3):265-280, (2005).
Abstract: Computational toxicology is a new research initiative being developed within the Office of Research and Development (ORD) of the US Environmental Protection Agency (EPA). Operationally, it is defined as the application of mathematical and computer models together with molecular chemistry and biological approaches to improve our understanding of the key toxicological issues faced by the regulatory program offices of EPA. A two-day workshop on the topic was held on September 29-30, 2003, at the EPA's Research Triangle Park campus in North Carolina. The focus of the workshop was on a proposal entitled A Framework for a Computational Toxicology Research Program in ORD (available with ancillary information at www.epa.gov/comptox), which identifies research needs to provide the basis for a focused and integrated research effort utilizing modern computing, chemistry, and molecular biology tools for developing in silico models that can predict the ecological and human health risk of potentially toxic chemicals. Traditional risk assessment of chemicals relies primarily on laboratory testing on a chemical-by-chemical basis to obtain data about adverse effects and the quantitative relationship between doses and likelihood of response. In human health risk assessment, these laboratory data are extrapolated to predict the likelihood of an adverse effect and to estimate risk to humans. The large number of chemicals in commerce for which assessments need to be made and the expense of testing limits our ability to apply standard toxicity testing methods to relatively few of the vast array of chemicals of interest and necessitates new scientific approaches to the problem. The proposal puts forth three strategic objectives of the emerging computational toxicology program in ORD to address this situation: (1) to improve linkages in the source to outcome paradigm used for risk assessment by EPA, (2) develop predictive models for hazard identification, and (3) improve quantitative risk assessment. The first objective is largely technology based, and is intended to develop the tools that will enable advances in the remaining two goals. The objectives are designed to enhance EPAs ability to prioritize and screen chemicals for toxicity for testing, and to develop accurate risk assessments more economically and efficiently. Overall, successful completion of these objectives would allow the EPA to more efficiently screen, test, and evaluate the toxicity of chemicals.

PAPER IN NON-EPA PROCEEDINGS Organic Waste Contamination Indicators in Small Georgia Piedmont Streams 04/28/2005
Burke Jr., R A. AND J. Molinero. Organic Waste Contamination Indicators in Small Georgia Piedmont Streams. In Proceedings, 2005 Georgia Water Resources Conference, Athens, GA, April 25 - 27, 2005. University of Georgia, Athens, GA, 529-532, (2003).
Abstract: We monitored concentrations of nitrous oxide, methane, carbon dioxide, nutrients and other parameters (T, conductivity, dissolved oxygen, alkalinity, pH, DOC, DON, flow rate) in 17 headwater streams (watershed sizes from 0.5 to 3.4 kilometers) of the South Fork Broad River watershed on a monthly basis for a year. We measured the stable nitrogen isotope ratio of plants growing in the channel and potential denitrification rate in the sediments on a few dates. Land use in the small watersheds that we studied was derived from the National Land Cover Data (NLCD) database. Based on monthly monitoring results our initial research suggested that although TDN, DOC, nitrous oxide, methane, and carbon dioxide in streams are all effective indicators of stream impairment by organic wastes and/or nutrients from septic tanks and/or animal manure, the trace gas concentrations are more sensitive indicators that respond to lower levels of waste contamination than do TDN and DOC. Our recent research suggests that stable nitrogen isotope ratios and potential denitrification rates are positively correlated with estimates of watershed waste loading and thus also appear to be potentially effective indicators of waste contamination in these watersheds. Trace gas, isotopic, potential denitrification rate, and other biogeochemical indicators of organic waste and/or nutrient contamination may have value to managers and regulators trying to protect water quality.

PRESENTATION EPA's Computational Toxicology Research Program: Developing Tools for Identifying Environmental Contaminants of Concern 12/16/2005
WEBER, E. J. EPA's Computational Toxicology Research Program: Developing Tools for Identifying Environmental Contaminants of Concern. Presented at Pacifichem 2005, Honolulu, HI, December 15 - 20, 2005.
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 3mra: A Multi-Media Human and Ecological Modeling System for Site-Specific to National Scale Regulatory Applications 12/13/2005
LANIAK, G. F., J. E. BABENDREIER, S. KRONER, Z. SALEEM, K. L. WOLFE, AND R. S. PARMAR. 3mra: A Multi-Media Human and Ecological Modeling System for Site-Specific to National Scale Regulatory Applications. Presented at Board of Scientifc Counselors Land Goal Research Program Review, Cincinnati, OH, December 13 - 15, 2005.
Abstract: 3MRA provides a technology that fully integrates the full dimensionality of human and ecological exposure and risk assessment, thus allowing regulatory decisions a more complete expression of potential adverse health effects related to the disposal and reuse of contaminated wastestreams. 3MRA provides a technology that facilitates research, model development, and regulatory assessment. This, in turns, establishes a pathway for assimilating modeling-based research products directly into regulatory-based assessments.

PRESENTATION EPA Modeling Tools for Capture Zone Delineation 12/13/2005
KRAEMER, S. R. AND H. M. HAITJEMA. EPA Modeling Tools for Capture Zone Delineation. Presented at National Ground Water Association Ground Water Expo, Marietta, GA, December 13 - 16, 2005.
Abstract: The EPA Office of Research and Development supports a step-wise modeling approach for design of wellhead protection areas for water supply wells. A web-based WellHEDSS (wellhead decision support system) is under development for determining when simple capture zones (e.g., centric circular, eccentric circular, boat-shaped) would be protective given limited available data. The presentation will also discuss when full-featured professional modeling tools and additional data collection is appropriate.

PRESENTATION A Comparative Risk Reduction Analysis of the Office of Solid Waste's Waste Minimization Priority Chemicals Initiative Using the 3mra Multimedia Modeling System 12/13/2005
BABENDREIER, J. E., W. BRANDES, Z. SALEEM, S. KRONER, R. S. PARMAR, AND K. L. WOLFE. A Comparative Risk Reduction Analysis of the Office of Solid Waste's Waste Minimization Priority Chemicals Initiative Using the 3mra Multimedia Modeling System. Presented at Board of Scientific Counselors Land Goal Research Program Review, Cincinnati, OH, December 13 - 15, 2005.
Abstract: A study was initiated by the EPA/ORD National Exposure Research Lab (NERL) in FY05 to quantify risk reduction resulting from this national EPA initiative to reduce WMPC disposal. Using the 3MRA modeling system, which was recommended for use by the EPA Science Advisory Board for national-scale risk assessment of waste management units, we will develop a performance measure by comparatively assessing reduction in risks to ecological and human populations resulting from achievement of current and future waste reduction goals, for up to 9 of 31 WMPCs (e.g., Pb, Hg, TCDD). The study will address waste stream flows into five waste management types associated with industrial Subtitle D facilities. This national-scale risk reduction assessment will quantify uncertainty and variability in a wide range of factors that describe waste management environments at industrial facilities across the country. The study will also be able to assess specific subpopulations of receptors experiencing more or less benefit. An outcome of this work will be an ability to quantify, on a national-scale, the reduction in risk to human and ecological receptors resulting from the reduction of selected WMPCs (i.e., persistent, bioaccumulative, and toxic chemicals) found within waste streams reaching industrial solid waste management facilities. The study will ultimately provide a useful, quantifiable metric (accountability) of benefits associated with the RCC WMPC program.

PRESENTATION Model Evaluation Science to Meet Today's Quality Assurance Requirements for Regulatory Use: Addressing Uncertainty, Sensitivity, and Parameterization 12/13/2005
BABENDREIER, J. E., K. L. WOLFE, R. S. PARMAR, AND G. F. LANIAK. Model Evaluation Science to Meet Today's Quality Assurance Requirements for Regulatory Use: Addressing Uncertainty, Sensitivity, and Parameterization. Presented at Board of Scientific Counselors Land Goal Research Program Review, Cincinnati, OH, December 13 - 15, 2005.
Abstract: The EPA/ORD National Exposure Research Lab's (NERL) UA/SA/PE research program addresses both tactical and strategic needs in direct support of ORD's client base. The design represents an integrated approach in achieving the highest levels of quality assurance in environmental decision-making, with technology development focuses on: (a) methods for holistic compositional and performance based model evaluation; (b) tools for uncertainty analysis and parameter estimation; (c) tools for conducting screening, local, and global-based sensitivity analyses; (d) tools for communicating uncertainty in outcomes and how best to reduce it; (e) methods and tools for addressing the computational burdens of quality assurance; (f) model evaluation demonstrations supporting selected research applications; and (g) national and international outreach efforts (leveraging collaborations and tools outside of EPA). This research is enhancing multimedia modeling and performance-based assessments underpinning major Agency initiatives. In the future, model evaluation will be a requisite decision-making component needed to analyze performance in achieving environmental benefits. Improving the overall efficiency of regulatory programs, this research is directly supporting multiple Program Office and ORD missions in allowing EPA to improve models and regulatory programs through better characterization of model sensitivities and uncertainties. Results from complementary approaches being undertaken to enhance model evaluation science and the Agency's capabilities will help EPA form the needed technical basis to: 1) better drive strategic research planning by identifying needs for improved science and data; 2) more accurately identify uncertainty in exposure and risk assessments of solid and hazardous waste management facilities; and 3) directly support the Office of Solid Waste and Emergency Response's (OSWER) Resource Conservation Challenge and One Cleanup Initiatives.

PRESENTATION New Programming Environments for Uncertainty Analysis 12/06/2005
HILL, M. C., E. P. POETER, E. R. BANTA, S. CHRISTENSEN, R. L. COOLEY, D. M. ELY, J. E. BABENDREIER, G. LEAVESLEY, M. TONKIN, AND R. JULICH. New Programming Environments for Uncertainty Analysis. Presented at American Geophysical Union Fall Meeting, San Francisco, CA, December 05 - 09, 2005.
Abstract: We live in a world of faster computers, better GUI's and visualization technology, increasing international cooperation made possible by new digital infrastructure, new agreements between US federal agencies (such as ISCMEM), new European Union programs (such as Harmoniqua), and greater collaboration between US university scientists through CUAHSI. These changes provide new resources for tackling the difficult job of quantifying how well our models perform. This talk introduces new programming environments that take advantage of these new developments and will change the paradigm of how we develop methods for uncertainty evaluation. For example, the programming environments provided by COSU API, JUPITER API, and Sensitivity/Optimization Toolbox provide enormous opportunities for faster and more meaningful evaluation of uncertainties. Instead of waiting years for ideas and theories to be compared in the complex circumstances of interest to resource managers, these new programming environments will expedite the process. In the new paradigm, unproductive ideas and theories will be revealed more quickly, productive ideas and theories will more
quickly be used to address our increasingly difficult water resources problems. As examples, two ideas in JUPITER API applications are presented: uncertainty correction factors that account for system complexities not represented in models, and PPR and OPR statistics used to identify new data needed to reduce prediction uncertainty.

PRESENTATION UV Attenuation Near Coral Reefs in the Florida Keys: Light Absorption By Cdom and Particles 12/05/2005
SHANK, G. C., R. G. ZEPP, AND E. BARTELS. UV Attenuation Near Coral Reefs in the Florida Keys: Light Absorption By Cdom and Particles. Presented at American Geophysical Union Fall Meeting, San Francisco, CA, December 05 - 09, 2005.
Abstract: We have investigated the roles of chromophoric dissolved organic matter (CDOM) and suspended particles in the attenuation of UV radiation in the middle and lower regions of the Florida Keys. Extended exposure to UV radiation, along with elevated sea surface temperatures, impairs physiological processes in corals and contributes to bleaching episodes. Our research also has implications for remote sensing applications as light absorbed by particles must be considered when modeling optical data from satellites.

PRESENTATION The Aquatox Model 12/04/2005
RASHLEIGH, B. The Aquatox Model. Presented at NATO Advanced Study Institute, Dalyan, TURKEY, December 04 - 16, 2005.
Abstract: This lecture will present AQUATOX, an aquatic ecosystem simulation model developed by Dr. Dick Park and supported by the U.S. EPA. The AQUATOX model predicts the fate of various pollutants, such as nutrients and organic chemicals, and their effects on the ecosystem, including fish, invertebrates, and aquatic plants. A recently-developed estuarine version of the model simulates stratification, water and salt balance, and salinity effects on biological and chemical processes. The model can be used to predict ecological responses to proposed management alternatives.

PRESENTATION Wasp Transport Modeling and Wasp Ecological Modeling 12/04/2005
AMBROSE, R. B., T. A. WOOL, AND C. D. KNIGHTES. Wasp Transport Modeling and Wasp Ecological Modeling. Presented at NATO Programme Security Through Science, Dalyan, TURKEY, December 04 - 16, 2005.
Abstract: A combination of lectures, demonstrations, and hands-on excercises will be used to introduce pollutant transport modeling with the U.S. EPA's general water quality model, WASP (Water Quality Analysis Simulation Program). WASP features include a user-friendly Windows-based interface, a data pre-processor, a selection of water quality modules, and a graphical post-processor.

PRESENTATION Cic Response to Hurricane Katrina 12/01/2005
KITCHENS, J. Cic Response to Hurricane Katrina. Presented at Wolfskin Volunteer Fire Department Business Meeting, Arnoldsville, GA, December 01, 2005.
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 Toxicity-Based Identification of Drinking Water Disinfection By-Products Using Esi-MS and Esi-MS/MS 11/30/2005
RICHARDSON, S. D., F. G. CRUMLEY, J. CHOI, M. J. PLEWA, E. D. WAGNER, T. H. MIZE, R. ORLANDO, R. N. WINN, L. WILLIAMSON, AND M. BARTLETT. Toxicity-Based Identification of Drinking Water Disinfection By-Products Using Esi-MS and Esi-MS/MS. Presented at 18th Annual Tandem Mass Spectrometry Workshop, Lake Louise, AB, CANADA, November 30 - December 03, 2005.
Abstract: The goal of this research is to use a bio-assay directed approach to focus identification work on the most toxicologically important disinfection by-products. To this end, drinking water is being collected from full-scale treatment plants that use chlorine, ozone, chlorine dioxide, and chloramines as disinfectants, and this drinking water is being fractionated according to polarity (through the use of different polarity XAD resins, preparatory liquid chromatography columns, and solvent gradients) and molecular size (through the use of ultrafiltration and size exclusion chromatography).

PRESENTATION Metabolomics as a Diagnostic Tool for Small Fish Toxicology 11/17/2005
COLLETTE, T. W., D. R. EKMAN, J. F. KENNEKE, T. L. WHITEHEAD, D. L. VILLENEUVE, M. D. KAHL, K. M. JENSEN, AND G. T. ANKLEY. Metabolomics as a Diagnostic Tool for Small Fish Toxicology. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MA, November 13 - 17, 2005.
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 Determination of Perfluorinated Chemicals (Pfcs) in Soils, Sediment and Other Matrices 11/17/2005
ELLINGTON, J. J., J. W. WASHINGTON, M. J. STRYNAR, J. J. EVANS, T. M. JENKINS, AND W. M. HENDERSON. Determination of Perfluorinated Chemicals (Pfcs) in Soils, Sediment and Other Matrices. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
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 Aerobic Denitrification at Low No3 and Organic Carbon Concentrations 11/17/2005
THOMAS, R. C., J. W. WASHINGTON, AND L. SAMARKINA. Aerobic Denitrification at Low No3 and Organic Carbon Concentrations. Presented at Invited Lecture at the University of Georgia, Department of Geology, Athens, GA, November 17, 2005.
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 Design of Biodegradation Experiments for Fluorotelomer-Based Polymers 11/17/2005
WASHINGTON, J. W., J. J. ELLINGTON, T. M. JENKINS, J. J. EVANS, AND W. M. HENDERSON. Design of Biodegradation Experiments for Fluorotelomer-Based Polymers. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
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 Modeling the Response of a Variety of Freshwater Ecosystems to Changes in Atmospheric Hg Deposition Associated With the Clean Air Mercury Rule 11/16/2005
SUNDERLAND, E., C. D. KNIGHTES, R. B. AMBROSE, AND J. M. JOHNSTON. Modeling the Response of a Variety of Freshwater Ecosystems to Changes in Atmospheric Hg Deposition Associated With the Clean Air Mercury Rule. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
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 Enantioselective Chronic Toxicity of Fipronil in Ceriodaphnia Dubia 11/16/2005
WILSON, W. A., B. J. KONWICK, A. W. GARRISON, AND M. C. BLACK. Enantioselective Chronic Toxicity of Fipronil in Ceriodaphnia Dubia. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
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 Development and Application of a Tool for Evaluating Wildlife Exposure Risk Associated With Mercury-Contaminated Sediments 11/16/2005
KNIGHTES, C. D. Development and Application of a Tool for Evaluating Wildlife Exposure Risk Associated With Mercury-Contaminated Sediments. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
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 Acute Toxicity of Fipronil and Its Enantiomers to Marine and Freshwater Non-Targets 11/16/2005
OVERMYER, J., A. W. GARRISON, J. K. AVANTS, M. DELORENZO, P. KEY, K. CHUNG, B. KONWICK, W. A. WILSON, AND M. BLACK. Acute Toxicity of Fipronil and Its Enantiomers to Marine and Freshwater Non-Targets. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
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 Investigating the Enantioselective Toxicity of Conazole Fungicides in Rainbow Trout Through Nmr Based Metabolomics 11/14/2005
KONWICK, B., A. FISK, A. W. GARRISON, J. F. KENNEKE, AND D. R. EKMAN. Investigating the Enantioselective Toxicity of Conazole Fungicides in Rainbow Trout Through Nmr Based Metabolomics. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
Abstract: Recently, metabolomics, or the quantitative measurement of a broad spectrum of metabolic responses of living systems in response to disease onset or genetic modification, has been employed to enable rapid identification of the mechanisms of toxicity for compounds of environmental concern, such as the enantiomers of chiral pesticides. In this study, we investigated the potential for this new technology to differentiate the toxicities of the enantiomers of triadimefon and other conazoles in rainbow trout using nuclear magnetic resonance (NMR) spectroscopy.

PRESENTATION PCB 84: Disposition and Toxicity 11/14/2005
LEHMLER, H. J., P. S. KODAVANTI, D. J. PRICE, W. J. BIRGE, L. W. ROBERTSON, AND A. W. GARRISON. PCB 84: Disposition and Toxicity. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
Abstract: The findings of this study may have important implications for understanding the mechanism of neurotoxicity of chiral PCB congeners and further investigations of the disposition and toxicity of chiral PCBs are warranted.

PRESENTATION Metabolomics as a Diagnostic Tool for Small Fish Toxicology Research 11/14/2005
COLLETTE, T. W., D. R. EKMAN, J. F. KENNEKE, T. L. WHITEHEAD, D. L. VILLENEUVE, M. D. KAHL, K. M. JENSEN, AND G. T. ANKLEY. Metabolomics as a Diagnostic Tool for Small Fish Toxicology Research. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
Abstract: Metabolomics involves the application of advanced analytical and statistical tools to profile changes in levels of endogenous metabolites in tissues and biofluids resulting from disease onset or stress. While certain metabolites are being specifically targeted in these studies, we will also discern changes in the complete metabolic profile using NMR spectroscopic data with statistical approaches that allow capturing subtle changes in less-abundant metabolites. These data will be integrated with genomic, proteomic, and whole organism data from untreated fish and those exposed to known EDCs

PRESENTATION Meeting at Baltimore, Md: Distribution of Chiral PCBs in Selected Tissues in the Laboratory Rat 11/14/2005
LEHMLER, H. J., I. KANIA-KORWEL, J. K. AVANTS, K. C. HORNBUCKLE, L. W. ROBERTSON, W. W. SULKOWSKI, AND A. W. GARRISON. Meeting at Baltimore, Md: Distribution of Chiral PCBs in Selected Tissues in the Laboratory Rat. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
Abstract: In order to investigate the tissue distribution and enantiomeric fractions (EFs) of Polychlorinated Biphenyl (PCB) atropisomers, immature male Sprague-Dawley rats were administered environmentally relevant doses of (a) Aroclor 1254 or (b) an environmental mixture extracted from soil contaminated with Chlorofen, a Polish PCB mixture. The differences in the induction of PCB metabolizing enzymes may be responsible for the differences in the enantiomeric enrichment between both groups.

PRESENTATION Design of Biodegradation Experiments for Fluorotelomer-Based Polymers 11/14/2005
WASHINGTON, J. W., J. J. ELLINGTON, T. M. JENKINS, J. J. EVANS, AND W. M. HENDERSON. Design of Biodegradation Experiments for Fluorotelomer-Based Polymers. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
Abstract: Fluorotelomer-based polymers (FBPs) are used in a wide variety of consumer products and are widely distributed throughout society. Accordingly, there is great interest in whether and how fast these materials might degrade in various environmental settings. A useful quality of FBPs is the chemical stability of the polymers and, therefore, half-lives are anticipated to be long relative to typical laboratory experiments.

PRESENTATION Enantioselective Chronic Toxicity of Fipronil in Ceriodaphnia Dubia 11/14/2005
WILSON, W. A., B. KONWICK, A. W. GARRISON, AND M. C. BLACK. Enantioselective Chronic Toxicity of Fipronil in Ceriodaphnia Dubia. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
Abstract: Fipronil is released into the environment in a racemic (1:1) mixture of two mirror image isomers, called enantiomers. Although enantiomers undergo the same abiotic reactions and have identical physical properties, they may exhibit differing biological activity. Fipronil exhibited enantioselective toxicity in acute (48 h) toxicity tests with the aquatic crustacean Ceriodaphnia dubia, with the (+) enantiomer being up to three times more toxic.

PRESENTATION Techniques for Determining UV Exposure in Coastal Waters: Case Study in South Florida 11/14/2005
ZEPP, R. G., G. C. SHANK, W. S. FISHER, W. L. MILLER, C. FICHOT, E. BARTELS, E. STABENAU, M. A. MORAN, AND R. LEE. Techniques for Determining UV Exposure in Coastal Waters: Case Study in South Florida. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
Abstract: The photosynthesis of coral reefs is inhibited by solar ultraviolet (UV) radiation and UV in combination with unusually high sea surface temperatures is believed to play an important role in coral bleaching. In this presentation we use a new technique based on remotely sensed ocean color to estimate UV attenuation in coastal areas. This technique is applied in a case study of the coral reefs in the South Florida region to estimate fluctuations in underwater solar spectral UV irradiance as a function of location and season.

PRESENTATION Increased Endocrine Activity of Xenobiotic Chemicals as Mediated By Metabolic Activation 11/14/2005
KOLANCZYK, R. C., M. A. TAPPER, B. NELSON, V. WEHINGER, J. S. DENNY, D. W. KUEHL, B. R. SHEEDY, C. S. MAZUR, J. F. KENNEKE, W. J. JONES, AND P. K. SCHMIEDER. Increased Endocrine Activity of Xenobiotic Chemicals as Mediated By Metabolic Activation. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
Abstract: This research is part of an effort to develop in vitro assays and QSARs applicable to untested chemicals on EPA inventories through study of estrogen receptor (ER) binding and estrogen mediated gene expression in fish. The current effort investigates metabolic activation of chemicals resulting in increased estrogenicity.

PRESENTATION QSAR Evaluation of ER Binding Affinity of Chemicals and Metabolites 11/13/2005
SERAFIMOVA, R., H. ALADJOV, R. C. KOLANCZYK, P. K. SCHMIEDER, Y. AKAHORI, W. J. JONES, AND O. MEKENYAN. QSAR Evaluation of ER Binding Affinity of Chemicals and Metabolites. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
Abstract: Chemicals in commerce are assessed for a variety of potential adverse effects. As governments around the globe strive to meet the challenge of assessing chemicals as endocrine disruptors, the need for hypothesis-driven strategies to prioritize chemicals for testing has risen to the forefront. As part of a larger research effort, this study describes quantitative structure-activity relationships (QSAR) to predict chemical ER binding using an iterative process of strategic selection of chemicals for testing, in vitro data generation, in silico model development, etc., to facilitate model evaluation and refinement for user-specified levels of predictive certainty.

PRESENTATION Determination of Perfluorinated Chemicals (Pfcs) in Soils, Sediment and Other Matrices 11/13/2005
ELLINGTON, J. J., J. W. WASHINGTON, M. J. STRYNAR, J. J. EVANS, T. JENKINS, AND W. M. HENDERSON. Determination of Perfluorinated Chemicals (Pfcs) in Soils, Sediment and Other Matrices. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
Abstract: Soils that receive land application of treated wastewater from carpet manufacturing plants were sampled for perfluorooctanoic acid (PFOA) and other perfluorinated chemicals (PFCs) that are potential degradation products of fluorotelomer-based polymers (FBPs). Soils from other potentially impacted sites and soils remote from exposure to PFCs (except by atmospheric deposition) were analyzed to determine ambient levels of PFCs as well.

PRESENTATION Performance, Reliability, and Improvement of a Tissue-Specific Metabolic Simulator 11/13/2005
MEKENYAN, O., W. J. JONES, P. K. SCHMIEDER, S. KOTOV, T. S. PAVLOV, AND S. DIMITROV. Performance, Reliability, and Improvement of a Tissue-Specific Metabolic Simulator. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Baltimore, MD, November 13 - 17, 2005.
Abstract: A methodology is described that has been used to build and enhance a simulator for rat liver metabolism providing reliable predictions within a large chemical domain. The tissue metabolism simulator (TIMES) utilizes a heuristic algorithm to generate plausible metabolic maps using a library of measured biotransformations and abiotic reactions. The TIMES simulator prioritizes the order of implementation of metabolic transformation reactions applied to a parent chemical by using probabilities determined from measured data, a significant improvement over earlier approaches.

PRESENTATION Effects of Fertilizer Addition on Microbial Respiration and Uptake of Carbon Monoxide in a Cerrado Soil 11/10/2005
MOLINA, M., R. G. ZEPP, A. KOZOVITS, J. BRESOLIN, AND M. BUSTAMANTE. Effects of Fertilizer Addition on Microbial Respiration and Uptake of Carbon Monoxide in a Cerrado Soil. Presented at LBA Science Meeting, Sao Paulo, BRAZIL, November 10 - 12, 2005.
Abstract: The savanna area in central Brazil (Cerrado) is undergoing rapid agricultural land use changes and these changes are often accompanied by fertilization of the land. Because fertilization is a widespread management practice in the Cerrado, it is important to understand the effect that such treatments have on the microbial decomposition rates of soil organic matter (SOM) of various qualities. We conducted laboratory incubation studies on the effects of added fertilizers on bacterial production of carbon dioxide (CO2) and consumption of carbon monoxide (CO) in soil samples obtained from native Cerrado areas (20-50% canopy cover). The effects of added fertilizers were investigated by comparing fluxes in controls with no added fertilizer and soils with added nitrogen (40 ?g/g of soil as (NH4)2SO4) and phosphorus (1 mg/g of soil as Ca(H2PO4)2+CaSO4?2H2O) in gas-tight jars maintaining the same soil moisture level throughout treatments. Soil respiration was analyzed assuming that the soil organic matter (SOM) could be described by a two-compartment model (labile and refractory SOM). Results indicate that during the first 10 days, respiration from the labile component of the SOM was enhanced by addition of both fertilizers. However, in longer-term incubations (>32 days) addition of phosphorus produced the largest enhancement in respiration from the more refractory SOM. CO was taken up by the soil cores in all cases and the uptake was quantified as deposition velocities. The deposition velocities were enhanced by the addition of fertilizer with particularly large effects observed with soil cores amended by phosphorus. Observed mean deposition velocities at 28 degrees C were: control 0.0059 cm s-1; with added N 0.0081 cm s-1; and with added P 0.010 cm s-1.

PRESENTATION Effects of Fertilizer Addition on Microbial Respiration and Uptake of Carbon Monoxide in a Cerrado Soil 11/10/2005
MOLINA, M., R. G. ZEPP, A. KOZOVITS, J. BRESOLIN, AND M. BUSTAMANTE. Effects of Fertilizer Addition on Microbial Respiration and Uptake of Carbon Monoxide in a Cerrado Soil. Presented at LBA Science Meeting, Sao Paulo, BRAZIL, November 10 - 12, 2005.
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 Evaluation of the Ability of a 3D Hydrodynamic and Transport Model to Simulate Highly Stratified Estuarine Flows 11/02/2005
AREGA, F. AND E. J. HAYTER. Evaluation of the Ability of a 3D Hydrodynamic and Transport Model to Simulate Highly Stratified Estuarine Flows. Presented at 9th Estuarine and Coastal Modeling Conference, Charleston, SC, October 31 - November 02, 2005.
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 Metabolism and Metabolic Activation of Chemicals: in-Silico Simulation 10/29/2005
MEKENYAN, O. G., S. D. DIMITROV, T. S. PAVLOV, W. J. JONES, AND P. K. SCHMIEDER. Metabolism and Metabolic Activation of Chemicals: in-Silico Simulation. Presented at 3rd International Symposium on Computational Methods in Toxicology and Pharmacology Integrating Internet Resources, Shanghai, CHINA, October 29 - November 01, 2005.
Abstract: The role of metabolism in prioritizing chemicals according to their potential adverse health effects is extremely important because innocuous parents can be transformed into toxic metabolites. This work presents the TIssue MEtabolism Simulator (TIMES) platform for simulating metabolism.

PRESENTATION In Vitro Metabolism of the Chiral Triazole Fungicide Bromuconazole 47 Using Substrate Depletion and Product Formation Kinetics in Rat Hepatic Microsomes 10/25/2005
MAZUR, C. S. AND J. F. KENNEKE. In Vitro Metabolism of the Chiral Triazole Fungicide Bromuconazole 47 Using Substrate Depletion and Product Formation Kinetics in Rat Hepatic Microsomes. Presented at International Society for the Study of Xenobiotics Conference, Maui, HI, October 23 - 27, 2005.
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 Enantioselective in Vitro Metabolism of the Triazole Fungicides Bromuconazole and Triadimefon Using Rat Hepatic Microsomes 10/25/2005
KENNEKE, J. F. AND C. S. MAZUR. Enantioselective in Vitro Metabolism of the Triazole Fungicides Bromuconazole and Triadimefon Using Rat Hepatic Microsomes. Presented at International Society for the Study of Xenobiotics Conference, Maui, HI, October 23 - 27, 2005.
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 Enantioselective in Vitro Metabolism of the Triazole Fungicides Bromuconazole and Triadimefon Using Rat Hepatic Microsomes 10/24/2005
KENNEKE, J. F. AND C. S. MAZUR. Enantioselective in Vitro Metabolism of the Triazole Fungicides Bromuconazole and Triadimefon Using Rat Hepatic Microsomes. Presented at International Society for the Study of Xenobiotics Conference, Maui, HI, October 23 - 27, 2005.
Abstract: We report on the in vitro metabolism of the enantiomers of two triazole fungicides: triadimefon [two enantiomers; 1-(4-chlorophneoxy)-3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)butan-2-one] and bromuconazole {two diastereomers, each having two enantiomers; 1-[(2RS,4RS:2RS,4SR)-4-bromo-2-(2,4-dichlorophenyl)tetrahdrofurfuryl]-1H-1,2,4-triazole} by rat hepatic microsomes. Concomitant substrate depletion and product formation kinetics were measured in all cases.

PRESENTATION In Vitro Metabolism of the Chiral Triazole Fungicide Bromuconazole 47 Using Substrate Depletion and Product Formation Kinetics in Rat Hepatic Microsomes 10/23/2005
MAZUR, C. S. AND J. F. KENNEKE. In Vitro Metabolism of the Chiral Triazole Fungicide Bromuconazole 47 Using Substrate Depletion and Product Formation Kinetics in Rat Hepatic Microsomes. Presented at 13th North American International Society for the Study of Xenobiotics Meeting, Maui, HI, October 23 - 27, 2005.
Abstract: Kinetic analysis of xenobiotic metabolism using in vitro hepatic microsomes are needed for predictive in vivo physiological modeling. Recently, much emphasis has been placed on the adverse effects of triazole fungicides in mammalian steroid metabolism. In vitro metabolism of the triazole fungicide bromuconazole 47, which contains two chiral centers and exists in commercial mixtures with bromuconazole 46, was investigated using rat liver microsomes.

PRESENTATION Developing Site-Specific Models for Forecasting Bacteria Levels at Coastal Beaches 10/20/2005
FRICK, W. E., D. S. FRANCY, R. A. DARNER, AND Z. GE. Developing Site-Specific Models for Forecasting Bacteria Levels at Coastal Beaches. Presented at 18th Biennial Conference of the Estuarine Research Federation, Norfolk, VA, October 16 - 20, 2005.
Abstract: The U.S.Beaches Environmental Assessment and Coastal Health Act of 2000 authorizes studies of pathogen indicators in coastal recreation waters that develop appropriate, accurate, expeditious, and cost-effective methods (including predictive models) for quantifying pathogens in coastal recreation waters. The U.S. Geological Survey developed models for predicting concentrations that exceed the bathing-water standard for Escherichia coli at Lake Erie beaches. The statistical models were specific to each beach, and the best were based on a unique combination of environmental and water-quality variables as explanatory factors, including wave height, wind direction, rainfall, and turbidity. The models can be used like weather forecasts to predict the probability that bathing water standards will be exceeded. The strategies and statistical techniques used to develop these methods are applied to a selected coastal beach in the formal, established way. A general modeling framework is also developed that is intended to allow users without extensive training in statistical techniques to create similar models. Results are compared and analyzed.

PRESENTATION Cdom Production By Mangrove Leaf Litter and Sargassum Colonies in Florida Keys Coastal Waters 10/20/2005
SHANK, G. C., R. LEE, R. G. ZEPP, AND E. BARTELS. Cdom Production By Mangrove Leaf Litter and Sargassum Colonies in Florida Keys Coastal Waters. Presented at 2006 Ocean Sciences Meeting, Honolulu, HI, February 20 - 24, 2006.
Abstract: We have investigated the importance of leaf litter from red mangroves (Rhizophora mangle) and living Sargassum plants as sources of chromophoric dissolved organic matter (CDOM) to the coastal ocean waters and coral reef system of the Florida Keys. The magnitude of UVB exposure to coral reefs in the Florida Keys exhibits substantial temporal variability controlled almost exclusively by the level of CDOM present in the water column. Previous research indicated that seagrasses are important local sources of CDOM, while tidally-exchanged Florida Bay water is the primary allochthonous source. Our data indicate that CDOM (using absorption coefficient at 305 nm as proxy) is released from both mangrove leaves (0.002-0.067 m-1g-1h-1) and Sargassum (0.004-0.012 m-1g-1h-1) at similar rates and that CDOM production increases sharply with temperature. Measured CDOM fluxes from both the mangrove litter and Sargassum plants were comparable to previous flux measurements for seagrasses in the Florida Keys. Release from mangrove litter depended greatly on the stage of senescence of the leaf as freshly fallen leaves exhibited the highest CDOM production while older decayed leaves released very little CDOM. Production of CDOM by Sargassum was highest in plants exposed to natural sunlight indicating that large Sargassum colonies may be important sources of CDOM to open ocean waters. The photobleaching half-life of CDOM produced from mangrove litter was ~24 h. We are currently investigating the photobleaching rates of CDOM released by the Sargassum colonies.

PRESENTATION Distribution of N and Other Redox-Sensitive Species in Two Adjacent Wetland Streams Draining An Agricultural Field in the Georgia Piedmont 10/18/2005
SCHROER, K., J. W. WASHINGTON, AND V. A. NZENGUNG. Distribution of N and Other Redox-Sensitive Species in Two Adjacent Wetland Streams Draining An Agricultural Field in the Georgia Piedmont. Presented at Geological Society of America Annual Meeting, Salt Lake City, UT, October 16 - 19, 2005.
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 Developing Site-Specific Models for Forecasting Bacteria Levels at Coastal Beaches 10/17/2005
FRICK, W. E., D. S. FRANCY, R. A. DARNER, AND Z. GE. Developing Site-Specific Models for Forecasting Bacteria Levels at Coastal Beaches. Presented at 18th Biennial Conference of the Estuarine Research Federation, Norfolk, VA, October 16 - 20, 2005.
Abstract: The U.S.Beaches Environmental Assessment and Coastal Health Act of 2000 authorizes studies of pathogen indicators in coastal recreation waters that develop appropriate, accurate, expeditious, and cost-effective methods (including predictive models) for quantifying pathogens in coastal recreation waters. The U.S. Geological Survey developed models for predicting concentrations that exceed the bathing-water standard for Escherichia coli at Lake Erie beaches. The statistical models were specific to each beach, and the best were based on a unique combination of environmental and water-quality variables as explanatory factors, including wave height, wind direction, rainfall, and turbidity. The models can be used like weather forecasts to predict the probability that bathing water standards will be exceeded. The strategies and statistical techniques used to develop these methods are applied to a selected coastal beach in the formal, established way. A general modeling framework is also developed that is intended to allow users without extensive training in statistical techniques to create similar models. Results are compared and analyzed and presented in this presentation.

PRESENTATION Raman Spectroscopy-Based Metabolomics: Evaluation of Sample Preparation and Optical Accessories 10/10/2005
CHERNEY, D. P. AND T. W. COLLETTE. Raman Spectroscopy-Based Metabolomics: Evaluation of Sample Preparation and Optical Accessories. Presented at Federation of Analytical Chemistry and Spectroscopy Societies Conference, Quebec City, QC, CANADA, October 09 - 13, 2005.
Abstract: The field of metabonomics/metabolomics involves observing endogenous metabolites from organisms that change in response to exposure to a stressor or chemical of interest. Methods are being developed for measuring the Raman spectra of low-concentration metabolites in urine. The goal of this study is to be able to both detect and quantify individual metabolites in urine. A list of 20 of the most concentrated metabolites in urine was compiled and standard solutions were prepared of both individual components and mixtures at physiologically relevant concentrations. Raman spectra of these were then compared with spectra of real urine samples. To prepare these samples for Raman spectroscopy, it was necessary to remove as many fluorescing molecules that reduce the S/N ratio of the non-fluorescing metabolites as possible. A variety of techniques were used to reduce fluorescence interference including charcoal filtration, ultrafiltration cells and photobleaching of samples. Two different excitation wavelengths (532 and 785nm) along with a cuvette and a waveguide (liquid core optical fiber) were employed to compare the S/N ratio of the metabolites found in urine. Lastly, the concentrations of the individual synthetic components were used to determine the concentration of those components in human urine samples via successive subtraction and with the use of PLS. Thus far, use the green wavelength (532 nm) with a waveguide and sample ultrafiltration has shown the most promise for quantification of metabolites. Subtraction of the individual component spectra shows that constructively interfering peaks may be individually quantified for some of the most concentrated samples.

PRESENTATION Sampling and Evaluation of Leaking Underground Storage Tank Sites 10/06/2005
WEAVER, J. W. Sampling and Evaluation of Leaking Underground Storage Tank Sites. Presented at Lecture at the University of Georgia Forestry Department, Athens, GA, October 06, 2005.
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 Drinking Water Disinfection By-Products and New Health Issues 10/05/2005
RICHARDSON, S. D. AND M. J. PLEWA. Emerging Drinking Water Disinfection By-Products and New Health Issues. Presented at 1st International Conference on Environmental Health, Atlanta, GA, October 05 - 07, 2005.
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 Aerobic Denitrification: Implications for Nitrogen Fate Modeling 10/05/2005
THOMAS, R. C., J. W. WASHINGTON, AND L. SAMARKINA. Aerobic Denitrification: Implications for Nitrogen Fate Modeling. Presented at Mississippi River Basin Nutrient Science Workshop, St. Louis, MO, October 05, 2005.
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 Nutrient Concentrations in Flowing Waters of the South Fork Broad River, Georgia Watershed 10/04/2005
BURKE, R. A., J. MOLINERO, D. L. SPIDLE, AND L. M. PRIETO. Nutrient Concentrations in Flowing Waters of the South Fork Broad River, Georgia Watershed. Presented at Mississippi River Basin Nutrients Science Workshop, St. Louis, MO, October 04 - 06, 2005.
Abstract: The South Fork Broad River (SFBR) drains about 635 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 disposed of by land application to pastures near the production site. Further, 90 % of the homes are on septic tanks so there is great potential for contamination by organic waste derived nutrients within the watershed. We monitored concentrations of nutrients, dissolved organic matter (DOM) and other parameters in 17 headwater streams, at three sites on the main stem, and in three major tributaries near their confluence with the SFBR on a monthly basis for over a year. Land use in the small watersheds that we studied was derived from the National Land Cover Data database. Concentrations of DOM, total dissolved nitrogen (TDN), and total dissolved phosphorous (TDP) were more variable in the more disturbed small streams than in the main stem or major tributary sites. Median concentrations of DOM, TDN, and TDP were much more variable among the small streams than among the main stem sites. DOM and nutrient concentrations varied little along the course of the main stem which suggests that relatively little DOM and nutrient processing occurs in the main stem. Watershed organic waste loading appears to be an important controller of small stream chemistry and our results suggest that some of the small watersheds are nearing a threshold of waste loading above which small stream chemistry and ecological function may be disturbed. If disturbance of the small watersheds within the SFBR watershed becomes extensive enough, the main stem may become impaired.

PRESENTATION Nutrient Concentrations in Flowing Waters of the South Fork Broad River, Georgia Watershed 10/04/2005
BURKE, R. A., J. MOLINERO, AND D. L. SPIDLE. Nutrient Concentrations in Flowing Waters of the South Fork Broad River, Georgia Watershed. Presented at Mississippi River Basin Nutrients Science Workshop, St. Louis, MO, October 04 - 06, 2005.
Abstract: We monitored concentrations of nutrients, dissolved organic matter (DOM) and other parameters in 17 headwater streams, at three sites on the main stem, and in three major tributaries near their confluence with the South Fork Broad River on a monthly basis for over a year. Concentrations of DOM, total dissolved nitrogen (TDN), and total dissolved phosphorous (TDP) were more variable in the small streams than in the main stem or major tributary sites. Median concentrations of DOM, TDN, and TDP were much more variable among the small streams than among the main stem sites.

PRESENTATION Aerobic Denitrification: Implications for Nitrogen Fate Modeling 10/04/2005
THOMAS, R., J. W. WASHINGTON, AND L. SAMARKINA. Aerobic Denitrification: Implications for Nitrogen Fate Modeling. Presented at Mississippi River Basin Nutrients Science Workshop, St. Louis, MO, October 04 - 06, 2005.
Abstract: In the Mississippi, as well as most nitrogen-degraded rivers and streams, NO3- is the dominant N species and therefore understanding its biogeochemical behavior is critical for accurate nitrogen fate modeling. To our knowledge this is the first work to report aerobic denitrification under conditions typically found in environmental settings, such as the Mississippi River Basin. Our discovery of aerobic denitrification is expected to have a high impact on N-fate modeling as most existing models call for denitrification to take place in anoxic settings, yet most impacted surface waters are aerobic.

PRESENTATION Abiotic Reduction of Nitroaromatics and Related Chemicals By Aqueous and Mineral-Associated Iron Species 10/04/2005
COLON, D. Abiotic Reduction of Nitroaromatics and Related Chemicals By Aqueous and Mineral-Associated Iron Species. Presented at 4th Annual Hispanic Research Scientific Seminar Series (Webinar to U.S. EPA locations in Washington, DC; Cincinnati, OH; Research Triangle Park, NC; and Boston, MA), Athens, GA, October 04, 2005.
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 Nutrient Concentrations in Flowing Waters of the South Fork Broad River, Georgia Watershed 10/04/2005
BURKE, R. A., J. MOLINERO, D. L. SPIDLE, AND L. M. PRIETO. Nutrient Concentrations in Flowing Waters of the South Fork Broad River, Georgia Watershed. Presented at Mississippi River Basin Nutrients Science Workshop, St. Louis, MO, October 04 - 06, 2005.
Abstract: We monitored concentrations of nutrients, dissolved organic matter (DOM) and other parameters in 17 headwater streams, at three sites on the main stem, and in three major tributaries near their confluence with the South Fork Broad River on a monthly basis for over a year. Concentrations of DOM, total dissolved nitrogen (TDN), and total dissolved phosphorous (TDP) were more variable in the small streams than in the main stem or major tributary sites. Median concentrations of DOM, TDN, and TDP were much more variable among the small streams than among the main stem sites.

PRESENTATION The Use of Local Mercury Deposition Measurements in Modeling the Fate, Transport and Bioaccumulation of Methylmercury on the Cheyenne River Sioux Tribal Lands 09/29/2005
JOHNSTON, J. M., D. HOFF, R. EDGAR, C. DUCHENEAUX, C. D. KNIGHTES, AND R. B. AMBROSE. The Use of Local Mercury Deposition Measurements in Modeling the Fate, Transport and Bioaccumulation of Methylmercury on the Cheyenne River Sioux Tribal Lands. Presented at NADP 2005: Science Supporting Resource Management, Jackson, WY, September 27 - 30, 2005.
Abstract: Managed farm ponds on Sioux Tribal lands were monitored as a part of a two year study to address the variation in methylmercury bioaccumulation in fishes from 2003-2004. Initial tissue residue monitoring suggested that larger ponds posed less risk for human exposure to methylmercury than smaller ponds; however, variation in hydrology, chemistry, food web dynamics and patterns of local deposition among ponds was uncharacterized.

PRESENTATION Dispersant Effectiveness on Oil Spills Impact of Environmental Factors 09/21/2005
DESHPANDE, N., S. CHANDRASEKAR, G. A. SORIAL, AND J. W. WEAVER. Dispersant Effectiveness on Oil Spills Impact of Environmental Factors. Presented at 2005 Annual Science Conference, International Council for the Expoloration of the Sea, Aberdeen, SCOTLAND, September 20 - 24, 2005.
Abstract: When a dispersant is applied to an oil slick, its effectiveness in dispersing the spilled oil depends on various factors such as oil properties, wave mixing energy, temperature of both oil and water, and salinity of the water. Estuaries represent water with varying salinities. In this study three salinity values in the range of 10-34 ppt (parts per thousand) were investigated, representing potential salinity concentrations found in typical estuaries. Three oils were chosen to represent light refined oil, light crude oil and medium crude oil. Each oil was tested at three weathering levels to represent maximum, medium and zero weathering. Two dispersants were chosen for evaluation. A modified trypsinizing flask termed the `Baffled Flask' was used for conducting the experimental runs. A full factorial experiment was conducted for each oil to investigate the effect of salinity on three environmental factors: temperature (4 levels), oil weathering (3 levels)and mixing energy (150,200 and 250 rpm). Each experiment was replicated four times in order to evaluate the accuracy of the test. Statistical analyses of the experimental data were performed separately for each of the three oils three times (with or without dispersant). A linear regression model representing the main factors (salinity, temperature, oil weathering and flask speed) and second order interactions among the factors were accurately fit to the experimental data. Salinity was found to play an important role in determining the significance of temperature and mixing energy on dispersant effectiveness for almost all the oil dispersant combinations. The impact of salinity at different weathering was only significant for South Louisiana Crude Oil with dispersant 'A'.

PRESENTATION Interactive Management Tools for Fish Response to Habitat in the Mid-Atlantic Highlands 09/15/2005
RASHLEIGH, B., J. M. JOHNSTON, M. C. BARBER, R. S. PARMAR, AND M. J. CYTERSKI. Interactive Management Tools for Fish Response to Habitat in the Mid-Atlantic Highlands. Presented at American Fisheries Society Annual Meeting, Anchorage, AK, September 11 - 15, 2005.
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 Identification and Prediction of Fish Assemblages in Streams of the Mid-Atlantic Highlands, USA 09/12/2005
CYTERSKI, M. J. Identification and Prediction of Fish Assemblages in Streams of the Mid-Atlantic Highlands, USA. Presented at American Fisheries Society Annual Meeting, Anchorage, AK, September 11 - 15, 2005.
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 Interactive Habitat Suitability Models for Stream Fishes in the Mid-Atlantic Highlands 09/12/2005
RASHLEIGH, B., R. S. PARMAR, AND J. M. JOHNSTON. Interactive Habitat Suitability Models for Stream Fishes in the Mid-Atlantic Highlands. Presented at American Fisheries Society Annual Meeting, Anchorage, AK, September 11 - 15, 2005.
Abstract: Models that predict the presence of stream fish species based on habitat characteristics can be useful in watershed management. We developed such models for each of fourteen Mid-Atlantic Highlands stream fish species/groups.

PRESENTATION Emerging DBPs and Other Contaminants in Drinking Water 09/07/2005
RICHARDSON, S. D. Emerging DBPs and Other Contaminants in Drinking Water. Presented at ITLA Meeting, Taunton, MA, September 07, 2005.
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 Evaluating and Managing Pesticide Spray Drift 09/06/2005
BIRD, S. L. Evaluating and Managing Pesticide Spray Drift. Presented at Children's Health Advisory Panel (Pesticide Subgroup) Conference Call, Washington, DC, September 06, 2005.
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 In Vitro Phase I Metabolism of the Triazole Fungicide Bromuconazole and Its Four Enantiomers 08/29/2005
KENNEKE, J. F., C. S. MAZUR, AND A. W. GARRISON. In Vitro Phase I Metabolism of the Triazole Fungicide Bromuconazole and Its Four Enantiomers. Presented at 230th American Chemical Society National Meeting, Washington, DC, August 28 - September 01, 2005.
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 Toxicity of Fipronil Enantiomers to the Water Flea and Black Fly 08/29/2005
KONWICK, B., A. W. GARRISON, A. FISK, M. BLACK, AND J. OVERMYER. Toxicity of Fipronil Enantiomers to the Water Flea and Black Fly. Presented at 230th American Chemical Society National Meeting, Washington, DC, August 28 - September 01, 2005.
Abstract: In this research, we analyzed the enantiomer-specific toxicity of fipronil using two aquatic invertebrate species. Acute toxicity to Ceriodaphnia dubia (water flea) indicated that the (+) enantiomer was significantly more toxic than the (-) enantiomer, with about a 3-fold difference in LC50 values. For Simulium vittatum IS-7 (black fly), both fipronil enantiomers were equally toxic. However, the response to fipronil was markedly different between the two invertebrate classes with the black fly being nearly 2 orders of magnitude more sensitive than the water flea.

PRESENTATION QSAR Study of the Reduction of Nitrobenzenes By Fe II Species: Effect of Ferric Oxides, Ph and Natural Organic Matter 08/29/2005
COLON, D., E. J. WEBER, AND J. L. ANDERSON. QSAR Study of the Reduction of Nitrobenzenes By Fe II Species: Effect of Ferric Oxides, Ph and Natural Organic Matter. Presented at 230th American Chemical Society National Meeting, ENVR117, Washington, DC, August 28 - September 01, 2005.
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 Enantiomer-Specific Fate and Effects of Chiral Pesticides 08/29/2005
GARRISON, A. W. AND J. K. AVANTS. Enantiomer-Specific Fate and Effects of Chiral Pesticides. Presented at 230th American Chemical Society National Meeting, Washington, DC, August 28 - September 01, 2005.
Abstract: This research provides examples of the techniques used for enantiomer separation, a necessity for measurement of enantioselectivity. Examples are also given of selectivity in soil and water microbial transformations with a variety of pesticides, including metalaxyl, dichlorprop, ruelene (cruformate), and others. The ultimate goal of this research is to provide data for help in determining whether the manufacture and use of single-enantiomer pesticides is of benefit to the environment.

PRESENTATION Bioaccumulation and Enantioselective Biotransformation of Fipronil and Selected Conazole Fungicides 08/29/2005
KONWICK, B., A. FISK, J. K. AVANTS, J. F. KENNEKE, AND A. W. GARRISON. Bioaccumulation and Enantioselective Biotransformation of Fipronil and Selected Conazole Fungicides. Presented at 230th American Chemical Society National Meeting, Washington, DC, August 28 - September 01, 2005.
Abstract: In this research, dietary accumulation and enantioselective biotransformation were determined for rainbow trout (Oncorhynchus mykiss) exposed separately to the phenylpyrazole insecticide fipronil and to a series of selected conazole fungicides. Bioaccumulation of each pesticide and resulting enantiomer fractions (EF) were measured
over time.

PRESENTATION The in Vitro Phase I Metabolism of the Triazole Fungicide Bromuconazole and Its Four Enantiomers 08/28/2005
KENNEKE, J. F., C. S. MAZUR, AND A. W. GARRISON. The in Vitro Phase I Metabolism of the Triazole Fungicide Bromuconazole and Its Four Enantiomers. Presented at 230th American Chemical Society National Meeting, Washington, DC, August 28 - September 01, 2005.
Abstract: The triazole fungicide bromuconazole contains two chiral centers and exists as two diastereomers, each with two enantiomers. It has been widely used as a mixture of its diastereomers on food products. Here we report on the in vitro metabolism of the individual and combined diastereomers and enantiomers of bromuconazole.

PRESENTATION Transformation of Nitrosobenzenes and Hydroxylanilines By Fe II Species: Elucidation of Mechanism, Effect of Ferric Oxides and Ph 08/28/2005
COLON, D., E. J. WEBER, J. L. ANDERSON, P. WINGET, AND L. A. SUAREZ. Transformation of Nitrosobenzenes and Hydroxylanilines By Fe II Species: Elucidation of Mechanism, Effect of Ferric Oxides and Ph. Presented at the Sci-Mix Section of the 230th American Chemical Society National Meeting, ENVR 178, Washington, DC, August 28 - September 01, 2005.
Abstract: Nitrosobenzenes, the first intermediates in the reduction of nitrobenzenes, were reduced by Fe(II) solutions as well as by Fe(II)-treated goethite suspensions (Fe(II)/G). Results indicate a reactivity trend in which electron-withdrawing groups in the para position increased the rate of reduction of the nitrosobenzenes.

PRESENTATION Transformation of Nitrosobenzenes and Hydroxylanilines By Fe (II) Species: Elucidation of Mechanism, Effect of Ferric Oxides and Ph 08/28/2005
COLON, D., E. J. WEBER, J. L. ANDERSON, P. WINGET, AND L. A. SUAREZ. Transformation of Nitrosobenzenes and Hydroxylanilines By Fe (II) Species: Elucidation of Mechanism, Effect of Ferric Oxides and Ph. Presented at 230th American Chemical Society National Meeting, ENVR 178, Washington, DC, August 28 - September 01, 2005.
Abstract: The purpose of this work was to (i) study the effect of structure composition on the reactivity of a series of N-hydroxylaniline and nitrosobenzene compounds toward their reduction by Fe(II) species, (ii) evaluate the usefulness of several chemical parameters for predicting the rate of reduction of N-hydroxylaniline compounds in Fe(II) systems, (iii) obtain an insight of the rate determining step for the reduction of N-hydroxylaniline compounds in such systems, (iv) study the effect of pH on the rate of reduction of p-cyano-N-hydroxylaniline (CNHA) and p-cyanonitrosobenzene (CNNO) in the presence of Fe(II) species and (v) determine the reactivity of various ferric oxides and the effect of their surface area loading, toward the reduction of CNHA. CNHA was selected as our model compound for the study of several environmentally relevant variables in the N-hydroxylaniline reduction because its pKa is low enough, i.e., -0.7 to -0.85 (17), to rule out changes in its speciation at the various experimental conditions used in this work.

PRESENTATION Investigating the Enantioselective Toxicity of Conazole Fungicides in Rainbow Trout Through the Use of Nmr Based Metabonomics 08/28/2005
EKMAN, D. R., B. KONWICK, J. F. KENNEKE, A. W. GARRISON, AND A. T. FISK. Investigating the Enantioselective Toxicity of Conazole Fungicides in Rainbow Trout Through the Use of Nmr Based Metabonomics. Presented at 230th American Chemical Society National Meeting, Washington, DC, August 28 - September 01, 2005.
Abstract: In support of the Environmental Protection Agency's Computational Toxicology Program, metabonomics, the quantitative measurement of a broad spectrum of metabolic responses of living systems in response to disease onset or genetic modification, is being employed to enable rapid identification of mechanisms of toxicity for compounds of environmental concern. Recently, we have begun to investigate the potential for this new technology to differentiate the toxicities of the enantiomers of triadimefon and other conazoles in rainbow trout using nuclear magnetic resonance (NMR) spectroscopy. Preliminary NMR data show a significant metabolic response to racemic triadimefon, fed to the trout through gavage, as indicated by differences in the endogenous metabolite pattern from that of a control.

PRESENTATION QSAR Study on Reduction of Nitrobenzenes By Fe II Species: Effect of Ferric Oxides, Ph and Natural Organic Matter 08/28/2005
COLON, D., E. J. WEBER, AND J. L. ANDERSON. QSAR Study on Reduction of Nitrobenzenes By Fe II Species: Effect of Ferric Oxides, Ph and Natural Organic Matter. Presented at the Sci-Mix Section of the 230th American Chemical Society National Meeting, ENVR 177, Washington, DC, August 28 - September 01, 2005.
Abstract: Nitroaromatics are reduced in anoxic Fe(II)/Fe(III) aqueous systems. Studies were performed on the reduction of a series of nitrobenzenes in Fe(II)-treated goethite suspensions (Fe(II)/G).

PRESENTATION Computer Tools and Online Calculators 08/11/2005
WEAVER, J. W. Computer Tools and Online Calculators. Presented at Interstate Technology Regulatory Commission MTBE Training Course, San Francisco, CA, August 10 - 12, 2005.
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 2004/2005 U.S. Gasoline Composition Study 08/11/2005
WEAVER, J. W. 2004/2005 U.S. Gasoline Composition Study. Presented at Interstate Technology Regulatory Commission MTBE Training Course, San Francisco, CA, August 10 - 12, 2005.
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 Plume Formation, Transport and Modeling 08/11/2005
WEAVER, J. W. Plume Formation, Transport and Modeling. Presented at Interstate Technology Regulatory Commission MTBE Training Course, San Francisco, CA, August 10 - 12, 2005.
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 Factors Influencing Exposure to Inorganic and Organic Nanomaterials in Aquatic Environments 07/28/2005
ZEPP, R. G. Factors Influencing Exposure to Inorganic and Organic Nanomaterials in Aquatic Environments. Presented at NHEERL Meeting, RTP, NC, July 28, 2005.
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 Temporal and Spatial Variability in the Soil Microbial Community Along An Elevation Gradient in Five Different Tropical Forests in Puerto Rico 07/28/2005
GARCIA, L. M., S. A. CANTRELL, AND M. MOLINA. Temporal and Spatial Variability in the Soil Microbial Community Along An Elevation Gradient in Five Different Tropical Forests in Puerto Rico. Presented at International Union of Micobiological Societies Meeting, San Francisco, CA, July 23 - 29, 2005.
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 Study of Soil and Leaf Litter Microbial Fatty Acid Profiles in Tabonuco Forest in the Luquillo Experimental Forest in Puerto Rico 07/28/2005
RIVERA-FIGUEROA, F. J., S. A. CANTRELL, AND M. MOLINA. Study of Soil and Leaf Litter Microbial Fatty Acid Profiles in Tabonuco Forest in the Luquillo Experimental Forest in Puerto Rico. Presented at International Union of Micobiological Societies Meeting, San Francisco, CA, July 23 - 29, 2005.
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 Temporal and Spatial Variability in the Soil Microbial Community Along An Elevation Gradient in Five Different Tropical Forests in Puerto Rico 07/24/2005
GARCIA, L. M., S. A. CANTRELL, AND M. MOLINA. Temporal and Spatial Variability in the Soil Microbial Community Along An Elevation Gradient in Five Different Tropical Forests in Puerto Rico. Presented at International Union of Micobiological Societies Meeting, San Francisco, CA, July 23 - 29, 2005.
Abstract: This study focuses on how the microbial community changes through forest type, time and space at a soil depth of 0-5 and 5-10 cm.

PRESENTATION Study of Soil and Leaf Litter Microbial Fatty Acid Profiles in Tabonuco Forest in the Luquillo Experimental Forest in Puerto Rico 07/24/2005
RIVERA-FIGUEROA, F. J., S. A. CANTRELL, AND M. MOLINA. Study of Soil and Leaf Litter Microbial Fatty Acid Profiles in Tabonuco Forest in the Luquillo Experimental Forest in Puerto Rico. Presented at International Union of Microbiological Societies Meeting, San Francisco, CA, July 23 - 29, 2005.
Abstract: The results of this study suggests that there are two significantly distinct microbial communities in the leaf litter and soil components of this tropical forest. Fungi are more abundant in the leaf litter while bacteria are more abundant in the soil.

PRESENTATION Characterizing Spatial and Temporal Dynamics: Development of a Grid-Based Watershed Mercury Loading Model 07/20/2005
Dai, T., R B. Ambrose Jr., K. Alvi, T A. Wool, H. Manguerra, M. Chokshi, H. Yang, AND S R. Kraemer. Characterizing Spatial and Temporal Dynamics: Development of a Grid-Based Watershed Mercury Loading Model. Presented at 2005 Watershed Management Conference, Williamsburg, VA, July 20-23, 2005.
Abstract: A distributed grid-based watershed mercury loading model has been developed to characterize spatial and temporal dynamics of mercury from both point and non-point sources. The model simulates flow, sediment transport, and mercury dynamics on a daily time step across a diverse landscape. The model is composed of six major components: (1) an ArcGIS interface for processing spatial input data; (2) a basic hydrological module; (3) a sediment transport module; (4) a mercury transport and transformation module; (5) a spreadsheet-based model post-processor; and (6) links to other models such as WASP and WhAEM 2000 developed by the U.S. Environmental Protection Agency (U.S. EPA). The model fully uses the grid processing capacity of the latest ArcGIS technology. The water balance, sediment generation and transport, and mercury dynamics are calculated for every grid within a watershed. Water and pollutants are routed daily throughout the watershed based on a unique and flexible algorithm that characterizes a watershed into many runoff travel-time zones. The mercury transport and transformation module simulates the following key processes: (1) mercury input from atmospheric deposition; (2) mercury assimilation and accumulation in forest canopy and release from forest fitter; (3) mercury input from bedrock weathering; (4) mercury transformation in soils; (5) mercury transformation in lakes and wetlands including reduction and net methylation; (6) mercury transport through sediment and runoff, and (7) mercury transport in stream channels. By using the grid-based technology, flow and mercury dynamics can be examined at any of several points in the watershed. The model is capable of supporting large-scale watershed modeling with high-resolution raster datasets and will be used in mercury research projects sponsored by U.S. EPA. The model is programmed in Visual Basic and requires two ArcGIS (version 9.0) components- ArcVIew 9 and the Spatial Analyst extension.

PRESENTATION Interactions of Nitrogen and Nonliving Organic Matter in the Formation and Decomposition of Cdom in Coastal Marine Environments 07/19/2005
MORAN, M. A., E. BIERS, R. G. ZEPP, AND G. C. SHANK. Interactions of Nitrogen and Nonliving Organic Matter in the Formation and Decomposition of Cdom in Coastal Marine Environments. Presented at Biomaterials & Environmental Marine Biotech Program Review, Arlington, VA, July 19 - 20, 2005.
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 Evaluating the Effect of Upstream Watershed Activities to Downstream Streamflow 06/28/2005
MOHAMOUD, Y. M. Evaluating the Effect of Upstream Watershed Activities to Downstream Streamflow. Presented at American Water Resources Association 2005 Summer Specialty Conference, Honolulu, HI, June 27 - 29, 2005.
Abstract: Linking the impacts of upstream activities such as urban development to changes in downstream streamflow is critical to achieving a balance between economic development and environmental protection as a basis for sustainable watershed development. This paper presents a modeling approach which allows resource managers to evaluate the cumulative impacts of urban development, construction of new storage reservoirs and water withdrawal on downstream water availability.

PRESENTATION Evaluating the Effect of Upstream Watershed Activities on Downstream Streamflow 06/28/2005
MOHAMOUD, Y. M. Evaluating the Effect of Upstream Watershed Activities on Downstream Streamflow. Presented at American Water Resources Association 2005 Summer Specialty Conference, Honolulu, HI, June 27 - 29, 2005.
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 Development of Environmental Fate and Metabolic Simulators 06/24/2005
COLLETTE, T. W., D. COLON, S. H. HILAL, W. J. JONES, J. F. KENNEKE, C. S. MAZUR, C. T. STEVENS, P. WINGET, K. L. WOLFE, AND E. J. WEBER. Development of Environmental Fate and Metabolic Simulators. Presented at Bioinformatics Open Source Conference (BOSC), Detroit, MI, June 23 - 24, 2005.
Abstract: Presented at Bioinformatics Open Source Conference (BOSC), Detroit, MI, June 23-24, 2005.

PRESENTATION Identification, Occurrence, and Toxicity of Unregulated Idsinfection By-Products (DBPs) 06/21/2005
RICHARDSON, S. D., A. B. DEANGELO, L. C. KING, D. M. DEMARINI, R. A. MINEAR, M. J. PLEWA, R. N. WINN, M. VINCENTI, U. KARST, S. W. KRASNER, AND H. S. WEINBERG. Identification, Occurrence, and Toxicity of Unregulated Idsinfection By-Products (DBPs). Presented at BOSC Drinking Water Review, Cincinnati, OH, June 21 - 23, 2005.
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 Toxicity-Based Identification of Drinking Water Disinfection By-Products Using LC/Esi-MS and Gc/Esi-MS/MS 06/20/2005
RICHARDSON, S. D., F. G. CRUMLEY, J. CHOI, T. H. MIZE, R. ORLANDO, M. J. PLEWA, AND E. D. WAGNER. Toxicity-Based Identification of Drinking Water Disinfection By-Products Using LC/Esi-MS and Gc/Esi-MS/MS. Presented at First International Workshop on Liquid Chromatography-Tandem Mass Spectrometry for Screening and Trace Level Quantitation in Environmental and Food Samples, Barcelona, SPAIN, June 20 - 21, 2005.
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 Toxicity-Based Identification of Drinking Water Disinfection By-Products Using LC/MS and LC/MS/MS 06/20/2005
RICHARDSON, S. D., F. G. CRUMLEY, J. CHOI, M. J. PLEWA, AND E. WAGNER. Toxicity-Based Identification of Drinking Water Disinfection By-Products Using LC/MS and LC/MS/MS. Presented at First International Workshop on Liquid Chromatography-Tandem Mass Spectrometry for Screening and Trace Level Quantitation in Environmental and Food Samples, Barcelona, SPAIN, June 20 - 21, 2005.
Abstract: The goal of this research is to use a bio-assay directed approach to focus identification work on the most toxicologically important disinfection by-products. To this end, drinking water is being collected from full-scale treatment plants that use chlorine, ozone, chlorine dioxide, and chloramines as disinfectants, and this drinking water is being fractionated according to polarity (through the use of different polarity XAD resins, preparatory liquid chromatography columns, and solvent gradients) and molecular size (through the use of ultrafiltration and size exclusion chromatography).

PRESENTATION Organophosphate Pesticide Degradation Under Drinking Water Treatment Conditions: Modeling Perspectives 06/16/2005
DUIRK, S. E. AND T. W. COLLETTE. Organophosphate Pesticide Degradation Under Drinking Water Treatment Conditions: Modeling Perspectives. Presented at American Water Works Association Conference, San Francisco, CA, June 12 - 16, 2005.
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 Iodoacids and Other Emerging DBPs 06/14/2005
RICHARDSON, S. D., F. G. CRUMLEY, J. J. ELLINGTON, J. J. EVANS, M. J. PLEWA, AND E. D. WAGNER. Iodoacids and Other Emerging DBPs. Presented at American Water Works Association Annual Conference, San Francisco, CA, June 12 - 16, 2005.
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 Organophosphate Pesticide Degradation Under Drinking Water Treatment Conditions: Modeling Perspectives 06/12/2005
DUIRK, S. E. AND T. W. COLLETTE. Organophosphate Pesticide Degradation Under Drinking Water Treatment Conditions: Modeling Perspectives. Presented at American Water Works Association Annual Conference, San Francisco, CA, June 12 - 16, 2005.
Abstract: The objectives of this work were to develop experimental approaches and a modeling philosophy to study degradation of organophosphate pesticides as a class under drinking water treatment conditions.

PRESENTATION Organophosphate Pesticide Degradation Under Drinking Water Treatment Conditions 06/12/2005
Duirk, S E. AND T W. Collette. Organophosphate Pesticide Degradation Under Drinking Water Treatment Conditions. Presented at American Water Works Association Annual Conference, San Francisco, CA, June 12-16, 2005.
Abstract: The Food Quality Protection Act (FQPA) of 1996 requires that all tolerances for pesticide chemical residuals in or on food be considered for anticipated exposure. Drinking water is considered a potential pathway for dietary exposure and there is reliable monitoring data for the source water. Approximately 95% of the U.S. population obtains potable water from community water systems. Conventional water treatment processes (e.g. coagulation/flocculation, sedimentation, and filtration) do not appear to remove or transform hydrophilic pesticides. However, disinfection and softening have been shown to chemically oxidize or catalyze hydrolysis of certain pesticides. Over 90% of all community water systems use free chlorine as both a primary and secondary disinfectant, and approximately 30% of the United States' drinking water plants serving populations of 100,000 or greater use up-flow lime softening. Therefore, base catalyzed hydrolysis and chemical oxidation can potentially transform the parent pesticide to either a less or more toxic stable end-product in potable water. Chlorine reacting with organophosphate (OP) pesticides that contain the thiophosphate functionality (P=S) often results in the formation of oxons (P=O) [5-7]. The resulting oxons are expected to be more toxic than the parent compound. However, the kinetics and mechanisms of these transformations have yet to be fully investigated and modeled. We chose chlorpyrifos (CP) as a representative pesticide to study and model the reaction of free chlorine (TOTOCl = HOCl + OCl-) with OP pesticides. The overall goal of this research is to assess the potential exposure of potable water consumers to pesticides and their transformation products after raw water has undergone water treatment (e.g. chlorine disinfection and water softening).

PRESENTATION Modeling Aquatic Fate and Bioaccumulation of Mercury in Waterbodies: Application of the Bass Model to the Lake Ontario Exposure Framework 06/09/2005
SUNDERLAND, E., J. M. JOHNSTON, AND M. C. BARBER. Modeling Aquatic Fate and Bioaccumulation of Mercury in Waterbodies: Application of the Bass Model to the Lake Ontario Exposure Framework. Presented at Mercury Multicompartment Modeling Workshop, IJC Biennial Meeting and Great Lakes Conference, Kingston, ON, CANADA, June 09 - 11, 2005.
Abstract: A modeling approach for waterbody fate and transformation of mercury species was developed for Lake Ontario. This framework includes the estimation of mercury inputs, including those from atmospheric deposition, tributary and point source loadings, outputs via outflows and volatilization and sediment sequestering. The US EPA BASS model (Bioaccumulation and Aquatic System Simulator) was applied to this framework to simulate the bioaccumulation and biomagnification in the Lake Ontario food chain.

PRESENTATION Measurement and Toxicity of Iodo-Acid Disinfection By-Products in Chloraminated Drinking Water 06/08/2005
RICHARDSON, S. D., J. J. ELLINGTON, F. G. CRUMLEY, J. J. EVANS, M. J. PLEWA, E. D. WAGNER, AND A. B. MCKAGUE. Measurement and Toxicity of Iodo-Acid Disinfection By-Products in Chloraminated Drinking Water. Presented at American Society of Mass Spectrometry Conference, San Antonio, TX, June 05 - 09, 2005.
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 Measurement and Toxicity of Iodo-Acid Disinfection By-Products in Chloraminated Drinking Water 06/06/2005
RICHARDSON, S. D., J. J. ELLINGTON, F. G. CRUMLEY, J. J. EVANS, M. J. PLEWA, AND E. D. WAGNER. Measurement and Toxicity of Iodo-Acid Disinfection By-Products in Chloraminated Drinking Water. Presented at American Society for Mass Spectrometry Conference, San Antonio, TX, June 05 - 09, 2005.
Abstract: The goal of this work was to develop an analytical method to quantify these five iodo-acids (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) in drinking water, measure their occurrence in several drinking waters treated with chloramination, determine whether they are maximized in waters treated with chloramines only (compared to chlorine and chlorine-chloramines), and investigate the mammalian cell cytotoxicity and genotoxicity of the four synthesized iodo-acids (beyond iodoacetic acid).

PRESENTATION Temporal Variability of Enterococci Species in Streams Impacted By Cattle Fecal Contamination 06/05/2005
MOLINA, M., J. MAIMES, J. FISHER, AND B. JOHNSON. Temporal Variability of Enterococci Species in Streams Impacted By Cattle Fecal Contamination. Presented at American Society for Microbiology Annual Meeting, Atlanta, GA, June 05 - 09, 2005.
Abstract: Temporal variability in the gastrointestinal flora of animals impacting water resources with fecal material can be one of the factors producing low source identification rates when applying microbial source tracking (MST) methods. Our objective is to identify and compare the temporal variability of enterococci species in cattle manure and in streams directly impacted by cattle manure.

PRESENTATION Meeting at Leipzig, Germany: Site Assessment With EPA's on-Line Tools 05/30/2005
WEAVER, J. W. Meeting at Leipzig, Germany: Site Assessment With EPA's on-Line Tools. Presented at MTBE and Fuel Oxygenates Training Session, Leipzig, GERMANY, May 30 - 31, 2005.
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 at Leipzig, Germany: Model Selection and Usage at Lust Sites 05/30/2005
WEAVER, J. W. Meeting at Leipzig, Germany: Model Selection and Usage at Lust Sites. Presented at MTBE and Fuel Oxygenates Training Session, Leipzig, GERMANY, May 30 - 31, 2005.
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 at Leipzig, Germany: Nationwide Gasoline Composition Study 05/30/2005
WEAVER, J. W. Meeting at Leipzig, Germany: Nationwide Gasoline Composition Study. Presented at MTBE and Fuel Oxygenates Training Session, Leipzig, GERMANY, May 30 - 31, 2005.
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 Potential Impact of Organic Wastes on Small Stream Water Quality 05/27/2005
BURKE, R. A. AND J. MOLINERO. Potential Impact of Organic Wastes on Small Stream Water Quality. Presented at American Geophysical Union/North American Benthological Society Annual Meeting, New Orleans, LA, May 23 - 27, 2005.
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 at Cophenhagen, Denmark: Nationwide Gasoline Composition Study 05/26/2005
WEAVER, J. W. Meeting at Cophenhagen, Denmark: Nationwide Gasoline Composition Study. Presented at MTBE and Fuel Oxygenates Training Session, Copenhagen, DENMARK, May 26 - 27, 2005.
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 at Copenhagen, Denmark: Model Selection and Usage at Lust Sites 05/26/2005
WEAVER, J. W. Meeting at Copenhagen, Denmark: Model Selection and Usage at Lust Sites. Presented at MTBE and Fuel Oxygenates Training Session, Copenhagen, DENMARK, May 26 - 27, 2005.
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 Coupled Free and Dissolved Phase Transport: New Simulation Capabilities and Parameter Inversion 05/26/2005
TONKIN, M., J. W. WEAVER, C. ZHENG, AND C. MUFFELS. Coupled Free and Dissolved Phase Transport: New Simulation Capabilities and Parameter Inversion. Presented at National Ground Water Association, MTBE and Perchlorate Conference, San Francisco, CA, May 26 - 27, 2005.
Abstract: The vadose zone free-phase simulation capabilities of the US EPA Hydrocarbon Spill Screening Model (HSSM)have been linked with the 3-D multi-species dissolved-phase contaminant transport simulator MT3DMS.

PRESENTATION Meeting at Copenhagen, Denmark: Site Assessment With EPA's on-Line Tools 05/26/2005
WEAVER, J. W. Meeting at Copenhagen, Denmark: Site Assessment With EPA's on-Line Tools. Presented at MTBE and Fuel Oxygenates Training Session, Copenhagen, DENMARK, May 26 - 27, 2005.
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 Coupled Free and Dissolved Phase Transport: New Simulation Capabilities and Parameter Inversion 05/26/2005
TONKIN, M., J. W. WEAVER, C. ZHENG, C. MUFFLES, AND J. RUMBAUGH. Coupled Free and Dissolved Phase Transport: New Simulation Capabilities and Parameter Inversion. Presented at 2005 National Ground Water Association Conference on MTBE and Perchlorate: Assessment, Remediation, and Public Policy, San Francisco, CA, May 26 - 27, 2005.
Abstract: The vadose zone free-phase simulation capabilities of the US EPA Hydrocarbon Spill Screening Model (HSSM) (Weaver et al., 1994) have been linked with the 3-D multi-species dissolved-phase contaminant transport simulator MT3DMS (Zheng and Wang, 1999; Zheng, 2005). The linkage provides the means to include multiple releases of light non-aqueous phase liquids (LNAPLs) in a numerical simulation of aquifer contamination. The HSSM simulates the release of an LNAPL, its migration to the water table, development of a lens-shaped body of LNAPL at the water table interface, and the dissolution and transport of contaminants in the saturated aquifer below. The HSSM is particularly suited to the analysis of underground storage tank spills and leaks. This paper describes the approach for linking the HSSM and MT3DMS programs, and presents an illustrative example simulation in which MT3DMS correctly executes the new HSS Package for multiple leaking underground storage tanks and then accurately solves the mass-transport equation.

PRESENTATION A Beach Forecasting Tool: Visual Beach Empirical Models for Predicting Beach Bacteria 05/25/2005
FRICK, W. E. AND Z. GE. A Beach Forecasting Tool: Visual Beach Empirical Models for Predicting Beach Bacteria. Presented at International Association of Great Lakes Research Annual Conference on Great Lakes Research, Ann Arbor, MI, May 23 - 27, 2005.
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 Potential Impacts of Organic Wastes on Small Stream Water Quality 05/23/2005
BURKE, R. A. AND J. MOLINERO. Potential Impacts of Organic Wastes on Small Stream Water Quality. Presented at American Geophysical Union/North American Benthological Society Annual Meeting, New Orleans, LA, May 23 - 27, 2005.
Abstract: We monitored concentrations of dissolved organic carbon (DOC), dissolved oxygen (DO) and other parameters in 17 small streams of the South Fork Broad River (SFBR) watershed on a monthly basis for 15 months. Our monthly monitoring results showed a strong inverse relationship between mean DOC and mean DO and suggested that concentrations of total nitrogen (TN), DOC, and the trace gases nitrous oxide, methane and carbon dioxide are impacted by organic wastes and/or nutrients from animal manure applied to the land and/or human wastes from wastewater treatment plants or septic tanks in these watersheds.

PRESENTATION Web-Based Watershed Management Tools for the Mid-Atlantic Highlands 05/17/2005
PARMAR, R. S., J. M. JOHNSTON, B. RASHLEIGH, Y. M. MOHAMOUD, M. J. CYTERSKI, J. NEWLAND, AND A. BONNER. Web-Based Watershed Management Tools for the Mid-Atlantic Highlands. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
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 Integrated Risk Analysis in Coastal Ecosystems: the Example of Mercury 05/17/2005
SUNDERLAND, E. AND J. M. JOHNSTON. Integrated Risk Analysis in Coastal Ecosystems: the Example of Mercury. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
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 Tying It All Together: EPA Field Studies and Models Used in the Clean Air Markets Rule 05/17/2005
AMBROSE, R. B., J. M. JOHNSTON, C. D. KNIGHTES, AND E. SUNDERLAND. Tying It All Together: EPA Field Studies and Models Used in the Clean Air Markets Rule. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
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 EPA Science Forum EPA's Toxicogenomics Partnerships Across Government, Academia and Industry 05/16/2005
DIX, D. J., W. BAO, H. REN, D. R. EKMAN, AND R. J. KAVLOCK. EPA Science Forum EPA's Toxicogenomics Partnerships Across Government, Academia and Industry. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
Abstract: Over the past decade genomics, proteomics and metabonomics technologies have transformed the science of toxicology, and concurrent advances in computing and informatics have provided management and analysis solutions for this onslaught of toxicogenomic data. EPA has been actively developing an intramural research program in genomics, proteomics and metabonomics through a series of strategic alliances between the Office of Research and Development (ORD) and external organizations. The National Health and Environmental Effects Research Laboratory (NHEERL), National Center for Computational Toxicology (NCCT), and the National Exposure Research Laboratory (NERL) have initiated a series of integrated studies wherein genomic, proteomic and metabonomic data are being generated from both in vivo and in vitro experiments.

PRESENTATION Serafm: An Ecological Risk Assessment Tool for Evaluating Wildlife Exposure Risk Associated With Mercury-Contaminated Sediment in Lake and River Systems 05/16/2005
KNIGHTES, C. D. Serafm: An Ecological Risk Assessment Tool for Evaluating Wildlife Exposure Risk Associated With Mercury-Contaminated Sediment in Lake and River Systems. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
Abstract: A spreadsheet model, SERAFM, Spreadsheet-based Ecological Risk Assessment for the Fate of Mercury, was developed that can be used as a risk assessment tool for mercury contaminated ecosystems. In this tool, process-based understanding of the chemical, physical, and biological processes governing mercury fate and transport is incorporated into a modeling framework to assist with a wildlife risk assessment for an aquatic ecosystem with mercury contaminated sediments.

PRESENTATION Differentiating Toxicities of Conazole Fungicides Through Metabonomic Analyses of Multiple Tissues 05/16/2005
EKMAN, D. R., H. C. KEUN, C. D. EADS, C. M. FURNISH, J. C. ROCKETT, AND D. J. DIX. Differentiating Toxicities of Conazole Fungicides Through Metabonomic Analyses of Multiple Tissues. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
Abstract: The conazole fungicides represent a large group of compounds widely used agriculturally for the protection of crop plants (Hutson 1998) and pharmaceutically in the treatment of topical and systemic infections (Sheehan 1999). In 1999, the latest period for which agricultural usage estimates are available, 79 and 556 million pounds of fungicide active ingredient were used in the US and world markets, respectively (Donaldson, 2002), creating concern over the impact these compounds may have through environmental exposure to humans and other organisms. In an attempt to better understand the toxicities of these compounds, an NMR-based metabonomics approach was used to determine differences in the toxicities of two conazole fungicides (myclobutanil and triadimefon) by analyses of metabolite changes occurring in blood serum, liver tissue, and testicular tissue of control and exposed rats.

PRESENTATION Model Uncertainty Analysis, Field Data Collection and Analysis of Contaminated Vapor Intrusion Into Buildings 05/16/2005
TILLMAN, F., J. W. WEAVER, D. L. SPIDLE, AND S. L. BIRD. Model Uncertainty Analysis, Field Data Collection and Analysis of Contaminated Vapor Intrusion Into Buildings. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
Abstract: To address uncertainty associated with the evaluation of vapor intrusion problems we are working on a three part strategy that includes: evaluation of uncertainty in model-based assessments; collection of field data and assessment of sites using EPA and state protocols.

PRESENTATION The Lba Project: Nutrient Cycles and Trace Gas Exchange in Savannas of Central Brazil 05/16/2005
ZEPP, R. G., R. A. BURKE, M. MOLINA, K. KISSELLE, M. BUSTAMANTE, A. KOZOVITS, AND A. PINTO. The Lba Project: Nutrient Cycles and Trace Gas Exchange in Savannas of Central Brazil. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
Abstract: The Cerrado of central Brazil is one of the largest savannah regions on Earth. The stressors affecting ecosystems in this region, including deforestation, fire, soil degradation, unwise agricultural practices, climate change, and urbanization, are all experienced in many U. S. ecosystems. Intense agricultural activities such as land clearing for soybean cultivation and cattle farming are rapidly changing the Cerrado. EPA scientists have been collaborating with ecologists from the Universidade de Brasmlia (UnB) in central Brazil to determine how several of these stressors are affecting soil nutrient cycling, decomposition and the soil-atmosphere exchange of carbon- and nitrogen-containing trace gases. The research is contributing data and scientific understanding for the development of models that describe these stressor-ecosystem interactions.

PRESENTATION Analysis of Gasolines for Their Impacts on Leaking Underground Storage Tank Sites 05/16/2005
WEAVER, J. W. Analysis of Gasolines for Their Impacts on Leaking Underground Storage Tank Sites. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
Abstract: A study of gasoline based on samples taken from around the U.S. is intended to address their impacts at leaking underground storage tank sites. The resulting data support EPA's development of datasets for use in simulation modeling and ongoing efforts to develop and evaluate modeling approaches.

PRESENTATION Estimating and Projecting Impervious Cover 05/16/2005
EXUM, L. R., S. L. BIRD, J. HARRISON, AND C. PERKINS. Estimating and Projecting Impervious Cover. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
Abstract: Effective methods to estimate and project impervious cover can help identify areas where a watershed is at risk of changing rapidly from one with relatively pristine streams to one with streams with significant symptoms of degradation. In collaboration with the USEPA, Region 4, a GIS approach using multiple data sources was developed for estimating and projecting impervious cover for small watersheds over a large area.

PRESENTATION Inverse Quantitative Structure Activity Relationship Analysis for Improving Predictions of Chemical Toxicity 05/16/2005
MARTIN, S., J. F. KENNEKE, W. M. BROWN, AND J. L. FAULON. Inverse Quantitative Structure Activity Relationship Analysis for Improving Predictions of Chemical Toxicity. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
Abstract: The toxic outcomes associated with environmental contaminants are often not due to the chemical form that was originally introduced into the environment, but rather to the chemical having undergone a transformation prior to reaching the vulnerable species. More importantly, the chemical is often transformed (or metabolized) to the toxic form inside the species of interest. This situation is so common that any tool for accurately predicting toxicity must include a module that accurately predicts metabolism. In response to this need, NERL/ERD-Athens is developing a metabolic simulator in support of ORDs Computational Toxicology Program.

PRESENTATION Aquatic Ecosystem Protection and Fisheries Management in the Mid-Atlantic Highlands (USA) Using What If: A Collaboration of the Canaan Valley Institute, the Office of Research and Development and Region III 05/16/2005
BARBER, M. C., F. BORSUK, PATRICIA BRADLEY, M. J. CYTERSKI, J. M. JOHNSTON, P. KINDER, T. DEMOSS, Y. M. MOHAMOUD, J. NEWLAND, R. S. PARMAR, J. POMPONIO, R. PRESTON, B. RASHLEIGH, L. REYNOLDS, F. E. STANCIL, AND K. L. WOLFE. Aquatic Ecosystem Protection and Fisheries Management in the Mid-Atlantic Highlands (USA) Using What If: A Collaboration of the Canaan Valley Institute, the Office of Research and Development and Region III. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
Abstract: As described in its Highlands Action Program, the Canaan Valley Institute (CVI) partnered with the US EPA to develop a watershed assessment and management tool that allows managers to evaluate riparian restoration actions to improve instream habitat quality and aquatic community sustainability.

PRESENTATION Factors Affecting Colored Dissolved Organic Matter in Aquatic Environments of the Southeastern United States 05/16/2005
ZEPP, R. G., G. C. SHANK, M. A. MORAN, W. SHELDON, AND W. MILLER. Factors Affecting Colored Dissolved Organic Matter in Aquatic Environments of the Southeastern United States. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
Abstract: The sunlight-absorbing (colored) component of dissolved organic matter (CDOM) in aquatic environments is widely distributed in freshwaters and coastal regions where it influences the fate and transport of toxic organic substances and biologically-important metals such as mercury, iron, and copper. In this research we have examined two key factors, microbial degradation and sorption, that affect the loss of CDOM in rivers, estuaries and coastal shelf regions of the southeastern U.S.

PRESENTATION Multivariate Curve Resolution of Nmr Spectroscopy Metabonomic Data 05/16/2005
ALAM, M. K., T. M. ALAM, AND D. R. EKMAN. Multivariate Curve Resolution of Nmr Spectroscopy Metabonomic Data. Presented at EPA Science Forum 2005, Washington, DC, May 16 - 18, 2005.
Abstract: Sandia National Laboratories is working with the EPA to evaluate and develop mathematical tools for analysis of the collected NMR spectroscopy data. Initially, we have focused on the use of Multivariate Curve Resolution (MCR) also known as molecular factor analysis (MFA), a technique used for pattern recognition and identification of chemical components. We will present results from the analysis of simulated data in order to assess the performance of MCR under several conditions.

PRESENTATION Approaches to Estimating Light Exposure of Coral Reefs 04/29/2005
ZEPP, R. G. Approaches to Estimating Light Exposure of Coral Reefs. Presented at Symbiofest, University of Georgia, Department of Ecology, Athens, GA, April 29, 2005.
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 Water Resources Component of the Ecological Footprint of a Federal Research Laboratory in Athens, Georgia 04/26/2005
KRAEMER, S. R. The Water Resources Component of the Ecological Footprint of a Federal Research Laboratory in Athens, Georgia. Presented at 2005 Georgia Water Resources Conference, Athens, GA, April 25 - 27, 2005.
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 Organic Waste Contamination Indicators in Small Georgia Piedmont Streams 04/26/2005
BURKE, R. A. AND J. MOLINERO. Organic Waste Contamination Indicators in Small Georgia Piedmont Streams. Presented at 2005 Georgia Water Resources Conference, Athens, GA, April 25 - 27, 2005.
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 Foodweb and Bioaccumulation Modeling for Lake Hartwell (Twelvemile Creek Arm) 04/25/2005
RASHLEIGH, B., M. C. BARBER, AND D. WALTERS. Foodweb and Bioaccumulation Modeling for Lake Hartwell (Twelvemile Creek Arm). Presented at 2005 Georgia Water Resources Conference, Athens, GA, April 25 - 27, 2005.
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 Foodweb Modeling for PCBs in the Twelvemile Creek Arm of Lake Hartwell, Ga/Sc 04/25/2005
RASHLEIGH, B., M. C. BARBER, AND D. WALTERS. Foodweb Modeling for PCBs in the Twelvemile Creek Arm of Lake Hartwell, Ga/Sc. Presented at 2005 Georgia Water Resources Conference, Athens, GA, April 25 - 27, 2005.
Abstract: The U.S. EPA is conducting a series of studies on the Sangamo-Weston Superfund Site near Clemson, SC, to examine the pollution of the Twelvemile Creek arm of Lake Hartwell by PCBs that were released from the site until the early 1990s. Monitoring data have shown that while PCB concentration in sediments declined since 1995, PCB concentrations in fish have not. The EPA aquatic ecosystem model AQUATOX has been applied to examine this system. This model provides an understanding of food web dynamics, characterization of bioaccumulation, and identification of most sensitive ecosystem components. The model may eventually be used in prediction of future PCB concentrations in fish under different scenarios for management.

PRESENTATION Organic Waste Contamination Indicators in Small Georgia Piedmont Streams 04/25/2005
BURKE, R. A. AND J. MOLINERO. Organic Waste Contamination Indicators in Small Georgia Piedmont Streams. Presented at 2005 Georgia Water Resources Conference, Athens, GA, April 25 - 27, 2005.
Abstract: We monitored concentrations of dissolved organic carbon(DOC) and dissolved oxygen (DO), and other parameters in 17 small streams of the South Fork Broad River watershed on a monthly basis for 15 months. Here we present estimates of the amounts of organic waste input to these watersheds and evaluate the possible impact of the waste on stream DOC concentrations. Our results suggest that application of poultry litter at recommended rates may impact stream DOC levels if applied to a high enough percentage of the watershed land area.

PRESENTATION Meeting at Chattanooga, Tn: Estimating and Projecting Impervious Cover in the Southeastern United States 04/19/2005
HARRISON, J., L. R. EXUM, S. L. BIRD, AND C. PERKINS. Meeting at Chattanooga, Tn: Estimating and Projecting Impervious Cover in the Southeastern United States. Presented at EPA Region 4 Tiered Aquatic Life Use Training/Workshop, Chattanooga, TN, April 19 - 21, 2005.
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 Research in Support of the Computational Toxicology Initiative 04/19/2005
WEBER, E. J. Research in Support of the Computational Toxicology Initiative. Presented at XII Russian Congress "Man and Drugs", Moscow, RUSSIA, April 18 - 22, 2005.
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 Research Programs at the Ecosystems Research Division, US Environmental Protection Agency 04/12/2005
RUSSO, R. C. Research Programs at the Ecosystems Research Division, US Environmental Protection Agency. Presented at Universidad del Turabo, Gurabo, PUERTO RICO, April 12, 2005.
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 Research Opportunities for University of Georgia Undergraduates at Erd 03/29/2005
DUIRK, S. E. Research Opportunities for University of Georgia Undergraduates at Erd. Presented at Informal Presentation at the University of Georgia, Athens, GA, March 29, 2005.
Abstract: The objective of this informal talk will be to briefly discuss research currently being conducted at ERD and emphasize environmental chemistry.

PRESENTATION Nationwide Gasoline Composition Study 03/16/2005
WEAVER, J. W. Nationwide Gasoline Composition Study. Presented at 17th Annual UST/LUST National Conference, Seattle, WA, March 14 - 16, 2005.
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 Empirical Partitioning Models for Pb and Cd Using Data from 13 Soils, Sediments and Aquifer Materials 03/15/2005
LOUX, N. T., S. M. HASSAN, AND C. R. CHAFIN. Empirical Partitioning Models for Pb and Cd Using Data from 13 Soils, Sediments and Aquifer Materials. Presented at 229th American Chemical Society National Meeting, San Diego, CA, March 13 - 17, 2005.
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 Effects of Moisture Transport Beneath Buildings on Vapor Intrusion Modeling 03/14/2005
TILLMAN, F. AND J. W. WEAVER. Effects of Moisture Transport Beneath Buildings on Vapor Intrusion Modeling. Presented at 17th Annual UST/LUST National Conference, Seattle, WA, March 14 - 16, 2005.
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 Composition of U.S. Gasolines in 2004 03/14/2005
WEAVER, J. W. Composition of U.S. Gasolines in 2004. Presented at 17th Annual UST/LUST National Conference, Seattle, WA, March 14 - 16, 2005.
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 On-Line Sensitivity Analysis of the Johnson & Ettinger Vapor Intrusion Model 03/14/2005
TILLMAN, F. AND J. W. WEAVER. On-Line Sensitivity Analysis of the Johnson & Ettinger Vapor Intrusion Model. Presented at 17th Annual UST/LUST National Conference, Seattle, WA, March 14 - 16, 2005.
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 at New Orleans, La: Mammalian Metabolism and Distribution of Perfluorooctyl Ethanol (8-2 Telomer Alcohol) and Its Oxidation Metabolites 03/07/2005
HENDERSON, W. M., S. E. DUIRK, E. J. WEBER, AND M. A. SMITH. Meeting at New Orleans, La: Mammalian Metabolism and Distribution of Perfluorooctyl Ethanol (8-2 Telomer Alcohol) and Its Oxidation Metabolites. Presented at Society of Toxicology 44th Annual Meeting, New Orleans, LA, March 06 - 10, 2005.
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 Mammalian Metabolism and Distribution of Perfluorooctyl Ethanol (8-2 Telomer Alcohol) and Its Oxidation Metabolites 03/06/2005
HENDERSON, W. M., S. E. DUIRK, E. J. WEBER, AND M. A. SMITH. Mammalian Metabolism and Distribution of Perfluorooctyl Ethanol (8-2 Telomer Alcohol) and Its Oxidation Metabolites. Presented at Society of Toxicology Meeting, New Orleans, LA, March 06 - 10, 2005.
Abstract: Perfluorinated compounds have been shown to be globally distributed, bioaccumulative, persistent and potentially toxic. It has been hypothesized that many precursor fluorinated compounds, including the telomer alcohols, degrade or metabolize to the common metabolite PFOA.
The objective of this study was to investigate the distribution and metabolism of the telomer alcohol in mice.

PRESENTATION Watershed Health Assessment Tools Investigating Fisheries (What-If) 03/03/2005
BARBER, M. C., M. J. CYTERSKI, J. M. JOHNSTON, Y. M. MOHAMOUD, B. RASHLEIGH, R. S. PARMAR, AND K. L. WOLFE. Watershed Health Assessment Tools Investigating Fisheries (What-If). Presented at Region 4 Monitoring Coordinators Meeting, Atlanta, GA, March 03, 2005.
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 at Atlanta, Ga: Estimating and Projecting Impervious Cover in the Southeastern United States 03/03/2005
HARRISON, J., L. R. EXUM, S. L. BIRD, AND C. PERKINS. Meeting at Atlanta, Ga: Estimating and Projecting Impervious Cover in the Southeastern United States. Presented at EPA Region 4 State/EPA Monitoring Coordinators' Meeting, Atlanta, GA, March 03, 2005.
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 Next Generation of Drinking Water Disinfection By-Products and Health Issues 02/11/2005
RICHARDSON, S. D. The Next Generation of Drinking Water Disinfection By-Products and Health Issues. Presented at Seminar at the University of Illinois, Urbana, IL, February 11, 2005.
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 Models for Submarine Outfall Validation and Prediction Uncertainties 02/04/2005
FRICK, W. E. Models for Submarine Outfall Validation and Prediction Uncertainties. Presented at 5th International Exhibition and Conference on Environmental Technology, Athens, GREECE, February 03 - 05, 2005.
Abstract: This presentation describes efforts to verify and validate dilution models.

PRESENTATION Models for Submarine Outfall Validation and Prediction Uncertainties 02/03/2005
FRICK, W. E. Models for Submarine Outfall Validation and Prediction Uncertainties. Presented at 5th International Exhibition and Conference on Environmental Technology, Athens, GREECE, February 03 - 05, 2005.
Abstract: This address reports on some efforts to verify and validate dilution models, including those found in Visual Plumes. This is done in the context of problem experience: a range of problems, including different pollutants such as bacteria; scales, including near-field and far-field effects; temporal extent, including analyses of extended time-series features; and adaptation, particularly the development of a new beach bacteria forecasting tool.

PRESENTATION The U.S. Environmental Protection Agency Visual Plumes Modeling Software 01/31/2005
FRICK, W. E. The U.S. Environmental Protection Agency Visual Plumes Modeling Software. Presented at Technical University of Crete Lecture, Crete, GREECE, January 31, 2005.
Abstract: The U.S. Environmental Protection Agency's Center for Exposure Assessment Modeling (CEAM) at the Ecosystems Research Division in Athens, Georgia develops environmental exposure models, including plume models, and provides technical assistance to model users. The mixing zone and far-field modeling application, Visual Plumes (VP), is a recent addition to the public-domain models available on the center's web page.

PRESENTATION Description of Three Dimensional Hydrodynamic Model Efdc 01/19/2005
HAYTER, E. J. Description of Three Dimensional Hydrodynamic Model Efdc. Presented at Contaminated Sediments Workshop, Santa Barbara, CA, January 17 - 21, 2005.
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 Overview of Contaminated Sediment Transport and Fate Issues Faced By EPA 01/18/2005
HAYTER, E. J. Overview of Contaminated Sediment Transport and Fate Issues Faced By EPA. Presented at Contaminated Sediments Worshop, Santa Barbara, CA, January 17 - 21, 2005.
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 Cooperative Development of a Searchable Metabolism Database (Metapath) 01/11/2005
MEKENYAN, O., J. F. KENNEKE, P. WINGET, K. L. WOLFE, W. J. JONES, AND J. M. LONG. Cooperative Development of a Searchable Metabolism Database (Metapath). Presented at Meeting with OPP, Washington, DC, January 11, 2005.
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.

PUBLISHED REPORT Working With Whaem2000: Capture Zone Delineation for a City Wellfield in a Valley Fill Glacial Outwash Aquifer Supporting Wellhead Protection 11/08/2005
KRAEMER, S. R., H. M. HAITJEMA, AND V. A. KELSON. Working With Whaem2000: Capture Zone Delineation for a City Wellfield in a Valley Fill Glacial Outwash Aquifer Supporting Wellhead Protection. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/151 (NTIS PB2006-102381), 2005.
Abstract: The purpose of this document is to introduce through a case study the use of the ground water geohydrology computer program WhAEM for Microsoft Windows (32-bit), or WhAEM2000. WhAEM2000 is a public domain, ground-water flow model designed to facilitate capture zone delineation and protection area mapping in support of the state's and tribe's Wellhead Protection Programs (WHPP) and Source Water Assessment Planning (SWAP) for public water well supplies in the United States. Program operation and modeling practice is covered in a series of progressively more complex representations of a well field tapping a glacial outwash aquifer. WhAEM2000 provides an interactive computer environment for design of protection areas based on simple WHPAs (e.g., radius methods, well in uniform flow solutions), and geohydrologic modeling methods. Protection areas are designed and overlaid upon US Geological Survey Digital Line Graph (DLG), Digital Raster Graphic (DRG) or other electronic base maps. Geohydrologic modeling for steady pumping wells, including the influence of hydrological boundaries, such as rivers, recharge, no-flow boundaries, and in-homogeneity zones, is accomplished using the analytic element method. Reverse gradient tracelines of known residence time emanating from the pumping center are used to delineate the capture zones. WhAEM2000 has import and export utilities for DXF files and Shapefiles. WhAEM2000 has on-line help and tutorials. Install scripts and base maps are available for download from the EPA Center for Exposure Assessment Modeling web site (www.epa.gov/athens/software/whaem/index.html).

PUBLISHED REPORT Uncertainty and the Johnson-Ettinger Model for Vapor Intrusion Calculations 09/29/2005
WEAVER, J. W. AND F. D. TILLMAN. Uncertainty and the Johnson-Ettinger Model for Vapor Intrusion Calculations. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/110 (NTIS PB2006101094), 2005.
Abstract: The Johnson-Ettinger Model is widely used for assessing the impacts of contaminated vapors on residential air quality. Typical use of this model relies on a suite of estimated data, with few site-specific measurements. Software was developed to provide the public with automated uncertainty analysis applied to the model. (See http://www.epa.gov/athens/onsite.) An uncertainty analysis was performed on the model, that accounted for synergistic effects among variable model parameters. This analysis showed that a simple one-at-a time parameter uncertainty analysis provides a rough guide for the uncertainty generated by individual parameters and allowed their ranking. The one-at-a-time analysis, however, underestimated the uncertainty in the model results when all or groups of parameters were assumed to be uncertain. An apparent increase in simulated cancer risk caused by the uncertainty introduced from the input parameters was as much as 1285%. The model response to the input parameters showed that for the example studied, there was a positive skew in the model response to parameter variation.

PUBLISHED REPORT Review of Recent Research on Vapor Intrustion 09/29/2005
TILLMAN, F. D. AND J. W. WEAVER. Review of Recent Research on Vapor Intrustion. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/106 (NTIS PB2006-101093), 2005.
Abstract: This report reviews current and recent research in the area of vapor intrusion of organic compounds into residential buildings. We begin with a description of the challenges in evaluating the subsurface-to-indoor air pathway. A discussion of the fate and transport mechanisms affecting vapors along this pathway is then presented. Following this discussion is a brief overview of current Federal regulations and proposed guidance concerning vapor intrusion. A review of site studies involving vapor intrusion that have been published in scientific literature is then presented, with a focus on evidence of the extent of the problem. Published approaches to modeling vapor intrusion are presented next, followed by conclusions and ideas about future research needs.

PUBLISHED REPORT Przm-3, a Model for Predicting Pesticide and Nitrogen Fate in the Crop Root and Unsaturated Soil Zones: User's Manual for Release 3.12.2 09/29/2005
SUAREZ, L. A. Przm-3, a Model for Predicting Pesticide and Nitrogen Fate in the Crop Root and Unsaturated Soil Zones: User's Manual for Release 3.12.2. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/111 (NTIS PB2006-101105), 2005.
Abstract: This publication contains documentation for the PRZM-3 model. PRZM-3 is the most recent version of a modeling system that links two subordinate models, PRZM and VADOFT, in order to predict pesticide transport and transformation down through the crop root and unsaturated soil zones. Enhancements to Release 3.0 reported herein include algorithms that also enable modeling of the nitrogen cycle soil kinetic processes, with the ability to track nitrogen discharges from a septic tank into the soil environment and its subsequent movement to groundwater. Additional included enhancements enable better simulation of physicochemical processes, increased flexibility in representing agronomic practices, and improved post-processing and data interpretation aids.

PUBLISHED REPORT Temporal and Spatial Variability of Fecal Indicator Bacteria: Implications for the Application of Mst Methodologies to Differentiate Sources of Fecal Contamination 09/29/2005
MOLINA, M. Temporal and Spatial Variability of Fecal Indicator Bacteria: Implications for the Application of Mst Methodologies to Differentiate Sources of Fecal Contamination. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/107 (NTIS PB2006-101102), 2005.
Abstract: Temporal variability in the gastrointestinal flora of animals impacting water resources with fecal material can be one of the factors producing low source identification rates when applying microbial source tracking (MST) methods. Understanding how bacterial species and genotypes vary over time is highly relevant when the fecal material used to create a source library is collected under very different seasonal conditions than the environmental sample. Our objective was to identify and compare the temporal and spatial variability of fecal indicator bacteria from a specific host in manure and water samples and evaluate the implications of such variability on microbial source tracking approaches and applications.

PUBLISHED REPORT Organophosphate Pesticide Degradation Under Drinking Water Treatment Conditions 09/29/2005
DUIRK, S. E. AND T. W. COLLETTE. Organophosphate Pesticide Degradation Under Drinking Water Treatment Conditions. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/103 (NTIS PB2006-101091), 2005.
Abstract: Chlorpyrifos (CP) was used as a model compound to develop experimental methods and prototype modeling tools to forecast the fate of organophosphate (OP) pesticides under drinking water treatment conditions. CP was found to rapidly oxidize to chlorpyrifos oxon (CPO) in the presence of free chlorine. The primary oxidant is hypochlorous acid (HOCl); thus, oxidation is more rapid at lower pH (i.e., below the pKa of HOCl at 7.5). At elevated pH, both CP and CPO are susceptible to alkaline hydrolysis and degrade to 3,5,6-trichloro-2-pyridinol (TCP), a stable end product. Furthermore, the hydrolysis of both CP and CPO to TCP was shown to be accelerated in the presence of free chlorine by OCl-. These observations regarding oxidation and hydrolysis are relevant to common drinking water treatment processes: disinfection and water softening, respectively. In this work, intrinsic rate constants for these processes were determined, and simple computer models have been developed that accurately predict the concentration of CP, CPO, and TCP as a function of pH, chlorine dose, CP concentration, and time after chlorine dosing. These models serve as a first step toward the development of tools to assess the assessment of risk associated with consuming treated drinking water whose source is contaminated with OP pesticides.

PUBLISHED REPORT Spraytran User's Guide: A GIS-Based Atmospheric Spray Droplet Dispersion Modeling System 09/29/2005
ALLWINE, K. J., F. C. RUTZ, J. DROPPO, S. L. BIRD, AND H. THISTLE. Spraytran User's Guide: A GIS-Based Atmospheric Spray Droplet Dispersion Modeling System. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/109 (NTIS PB2006-101099), 2005.
Abstract: The offsite drift of pesticide from spray operations is an ongoing source of concern. The SPRAY TRANsport (SPRAYTRAN) system, documented in this report, incorporates the near-field spray application model, AGDISP, into a meso-scale atmospheric transport model. The AGDISP model is a near-field modeling technology (<1000 m) used to evaluate primary drift from a single pesticide application to a single row crop field during neutral atmospheric conditions over level terrain with uniform surface characteristics under the assumption of uniform and constant meteorology. The SPRAYTRAN system incorporates the on-field deposition and near-field spray drift results from AGDISP into a meso-scale transport model through a geographic information system-based user interface. SPRAYTRAN also extends and uses the DUST TRANsport (DUSTRAN) modeling system to enhance the assessment of offsite drift of pesticides. DUSTRAN is being developed for the U.S. Department of Defense to assess training/testing range dust-oriented pollutant contributions to local and regional air quality, to help manage dust-generating activities, and to help develop dust-mitigation strategies. SPRAYTRAN allows the assessment of potential pesticide exposures from multiple applications to multiple fields in variable terrain with time-varying, non-uniform meteorology.

PUBLISHED REPORT Empirical Models of Pb and Cd Partitioning Using Data from 13 Soils, Sediments and Aquifer Materials 08/03/2005
LOUX, N. T., S. M. HASSAN, AND C. R. CHAFIN. Empirical Models of Pb and Cd Partitioning Using Data from 13 Soils, Sediments and Aquifer Materials. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/077 (NTIS PB2006-101101), 2005.
Abstract: Lead (Pb) and cadmium (Cd) are two of the most common toxicants found in contaminated environments. Because solubilization of these metallic elements from the solid phase can influence their fate, transport and bioavailability, the partitioning coefficient (Kd) for these metals between environmental solids and natural waters is a key parameter needed for assessing the risks posed by these two elements when present in environmental solids at elevated concentrations. In common with other ionizable contaminants, theoretical models applicable to all environments for assessing the partitioning behavior of Pb and Cd do not exist. Consequently, empirical partitioning models have been developed by the international technical research community. Using large datasets of Pb and Cd partitioning obtained from 13 aquifer materials, soils and sediments, two improved, commonly applicable, empirical models of extended accuracy and applicability were developed in this work.

PUBLISHED REPORT Modeling Monomethylmercury and Tributyltin Speciation With EPA's Geochemical Speciation Model Minteqa2 05/31/2005
Loux, N T. Modeling Monomethylmercury and Tributyltin Speciation With EPA's Geochemical Speciation Model Minteqa2. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/063 (NTIS PB2006-100890), 2005.
Abstract: Given the complexity of the various, simultaneous (and competing) equilibrium reactions governing the speciation of ionic species in aquatic systems, EPA has developed and distributed the geochemical speciation model MINTEQA2 (Brown and Allison, 1987, Allison et al., 1991; Hydrogeologic, 1999a, 1999b). The present work is designed to at least partially address a limitation found in earlier versions of MINTEQA2 by initiating a capability for modeling the aqueous speciation behavior of MMHg and TBT in environmental aquatic systems. Generally speaking, geochemical speciation models require both an innate database of reaction constants that enable one to model complex competitive geochemical speciation simulations and user input containing the total analytical concentrations of the reacting species of interest. It is the purpose of this document to develop a "first cut" modeling capability for both MMHg and TBT in EPA's geochemical speciation model MINTEQA2 by extending the existing reaction constant database. There is extensive ongoing research concerning the environmental speciation behavior of both MMHg and TBT and it is anticipated that future upgrades in this area will be necessary as more data becomes available.

PUBLISHED REPORT Estimating and Projecting Impervious Cover in the Southeastern United States 05/19/2005
EXUM, L. R., S. L. BIRD, J. HARRISON, AND C. A. PERKINS. Estimating and Projecting Impervious Cover in the Southeastern United States. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/061 (NTIS PB2005-108393), 2005.
Abstract: Urban/suburban land use is the most rapidly growing land use class. Along with increased development inevitably comes increased impervious surface--areas preventing infiltration of water into the underlying soil. The extensive hydrological alteration of watersheds associated with increased impervious cover is very difficult to control and correct relative to the impact of urbanization on waterways. Development practices that reduce impervious area and include preventative strategies to protect water quality are more effective and less costly than remedial restoration efforts. Simple and reliable methods to estimate and project impervious cover can help identify areas where a watershed is at risk of changing rapidly from a system with relatively pristine streams to one with significant symptoms of degradation. In this study, a method for estimating and projecting impervious cover for 12 and 14 digit HUCs over a large area was developed and tested. These methods were then applied in EPA Region 4's eight southeastern states to provide the Region with a screening tool to guide monitoring and educational efforts.

PUBLISHED REPORT Predicted Ground Water, Soil and Soil Gas Impacts from U.S. Gasolines, 2004, First Analysis of the Autumnal Data 03/15/2005
WEAVER, J. W., L. JORDAN, AND D. B. HALL. Predicted Ground Water, Soil and Soil Gas Impacts from U.S. Gasolines, 2004, First Analysis of the Autumnal Data. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-05/032 (NTIS PB2005-105435), 2005.
Abstract: Ninety six gasoline samples were collected from around the U.S. in Autumn 2004. A detailed hydrocarbon analysis was performed on each sample resulting in a data set of approximately 300 chemicals per sample. Statistical analyses were performed on the entire suite of reported chemicals.

SUMMARY Items to Consider Regarding Pfoa in Soils: Report for Oppt Public Docket 10/31/2005
WASHINGTON, J. W. AND T. W. COLLETTE. Items to Consider Regarding Pfoa in Soils: Report for Oppt Public Docket. U.S. Environmental Protection Agency, Washington, DC, EPA/600/S-06/001, 2005.
Abstract: Chemical data for perfluorinated octanoic acid (PFOA) and soil partitioning that are available in the literature and from third-parties were used to calculate the propensity for PFOA to sorb to soils. Based upon calculations described here-in, as well as monitoring data from near industrial facilities, PFOA does appear to partition to soil significantly.

 

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

 
Begin Site Footer

EPA Home | Privacy and Security Notice | Contact Us

Last Updated on Wednesday, March 04, 2009
URL: http://cfpub.epa.gov