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Ecosystems Research Division Publications: 2009

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This page lists publication titles, citations and abstracts produced by NERL's Ecosystems Research Division for the year 2009, organized by Publication Type. Your search has returned 132 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

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Presented/Published
BOOK CHAPTER Disinfection By-Products and Drinking Water Treatment 08/01/2009
RICHARDSON, S. D. Disinfection By-Products and Drinking Water Treatment. Chapter , J. Forare (ed.), Drinking Water - Sources, Sanitation and Safeguarding. Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning, Stockholm, Sweden, 92-101, (2009).
Abstract: The disinfection of drinking water has been rightly hailed as a public health triumph of the 20th century. Before its widespread use, millions of people died from waterborne diseases. Now, people in developed nations receive quality drinking water every day from their public water systems. However, chemical disinfection has also produced an unintended health hazard: the potential for cancer and reproductive and developmental effects (including early-term miscarriages and birth defects) that are associated with chemical disinfection by-products (DBPs). Research is being conducted worldwide to solve these important human health issues. Chemical disinfectants, like chlorine, ozone, chloramines, and chlorine dioxide, are used to kill harmful pathogens in drinking water, and produce safe, potable water. However, these disinfectants are also powerful oxidants, and can chemically react with the naturally occurring organic matter (mostly present from decaying leaves and other plant matter), and also bromide and iodide salts naturally present in some source waters (rivers, lakes, and groundwaters). Chlorine, ozone, chlorine dioxide, and chloramines are the most common disinfectants in use today, and each produces its own suite of DBPs in drinking water. Two non-chemical means of disinfecting drinking water—UV light and reverse osmosis (RO) membranes—are also gaining in popularity for disinfecting water, and these technologies may hold promise in reducing levels of DBPs formed in drinking water.

BOOK CHAPTER Free and Open Source GIS Tools: Role and Relevance in the Environmental Assessment Community 07/15/2009
PURUCKER, S. T., H. E. GOLDEN, G. F. LANIAK, L. S. MATOTT, D. J. MCGARVEY, AND K. L. WOLFE. Free and Open Source GIS Tools: Role and Relevance in the Environmental Assessment Community. , Chapter 18, M. Madden (ed.), Manual of Geographic Information Systems. American Society for Photogrammetry and Remote Sensing, Bethesda, MD, 293-310, (2009).
Abstract: The presence of an explicit geographical context in most environmental decisions can complicate assessment and selection of management options. These decisions typically involve numerous data sources, complex environmental and ecological processes and their associated models, risk assessment and cost-benefit considerations, as well as competing stakeholder interests that reflect different decision objectives. This trend has driven a steady increase in available GIS-based environmental decision support software toolkits. Free and open source software (FOSS) is a significant portion of these capabilities. This chapter surveys common environmental assessment tools used with GIS. It does not aim to be comprehensive, given the number of available tools, but to go into detail on a few selected tools. Although some of the tools can be linked to a proprietary GIS environment, the focus here is on FOSS approaches and available freeware (proprietary software distributed freely). Surveyed topics include tools for accessing environmental data sets, performing aquatic and terrestrial assessments, modeling atmospheric deposition processes, and handling uncertainty. The chapter concludes with a discussion of the advantages and limitations of FOSS GIS approaches for environmental assessments.

BOOK CHAPTER Sada: Ecological Risk Based Decision Support System for Selective Remediation 06/01/2009
PURUCKER, S. T., R. N. Stewart, AND C. J. Welsh. Sada: Ecological Risk Based Decision Support System for Selective Remediation. , Chapter 11, A. Marcomini, G.W. Suter, and A. Critto (ed.), Decision Support Systems for Risk Based Management of Contaminated Sites. Springer Science + Business Media, New York, NY, 239-256, (2009).
Abstract: Spatial Analysis and Decision Assistance (SADA) is freeware that implements terrestrial ecological risk assessment and yields a selective remediation design using its integral geographical information system, based on ecological and risk assessment inputs. Selective remediation is a process that achieves a local- and/or site-level media concentration level protective of a defined risk level while minimizing cleanup volume. Implementation requires inputs of contaminant analytical data, a model of the spatial distribution of contamination, and ecological exposure information and models, along with decision-maker cleanup criteria and spatial scale definition. The resulting remedial design is spatially-explicit and optimal for the inputs and decision objectives. A brief application illustrates the specification of an area of concern for short-tailed shrews (Blarina carolinensis) exposed to a polychlorinated biphenyl (PCB) contaminated site in Oak Ridge, Tennessee. Toxicologically-based cleanup criteria were applied to determine a spatially explicit remedial design that reduced shrew exposures to protective levels.

BOOK CHAPTER Chlorine Dioxide Chemistry, Reactions, and Disinfection By-Products 01/01/2009
RICHARDSON, S. D., C. RAV-ACHA, AND G. D. SIMPSON. Chlorine Dioxide Chemistry, Reactions, and Disinfection By-Products. , Chapter 2, State of the Science of Chlorine Dioxide in Drinking Water. Water Research Foundation and Fondazione AMGA, Denver, CO, 21-49, (2009).
Abstract: This chapter contains two main sections-the first section describes the chemistry and reactions of chlorine dioxide, and the second describes the disinfection by-products (DBPs) of chlorine dioxide and their control. A short section on Research Needs completes this chapter. The section on chemistry and reactions is presented first because it lays the foundation for the reactions that are possible with chlorine dioxide, and in many cases, helps to explain some of the DBPs that have been reported. This chapter is intended to provide an overview of chemistry, reactions, and DBPs of chlorine dioxide and, as such, is not meant to be an exhaustive treatise. An extensive reference list is provided for additional details, especially with regard to the mechanisms of reaction.

JOURNAL Light-Initiated Transformatioins of Fullerenol in Aqueous Media 12/15/2009
Kong, L., O. Tedrow, Y. F. Chan, AND R. G. ZEPP. Light-Initiated Transformatioins of Fullerenol in Aqueous Media. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 43(24):9155-9160, (2009).
Abstract: We provide the first evidence that a fullerene derivative can be extensively mineralized under environmental conditions by direct photolysis. Dissolved inorganic carbon (DIC) was identified as a major photoproduct of fullerenol, a hydroxylated C60 molecule and the ratio of moles DIC produced to moles of fullerenol reacted reached 28 or approximately 47% of complete mineralization on extensive irradiation by simulated solar radiation. The direct photoreaction kinetics of fullerenol in dilute aqueous solution can be described by pH-dependent biexponential rate expressions. This photoreaction slowed by a factor of 2 in nitrogen-saturated water. The oxygen dependence is attributed to photoinduced electron or hydrogen atom transfer from fullerenol to oxygen to produce superoxide ions with a quantum yield of 6.2 × 10−4. Fullerenol can photosensitize the production of singlet oxygen (1O2) in dilute aqueous solution with quantum yields ranging from 0.10 in acidic water to 0.05 in neutral and basic solution. However our results indicate that chemical reactions involving diffusive encounters between 1O2 or superoxide and fullerenol are too slow to significantly contribute to the fast component of fullerenol photoreaction in sunlight. The pH dependence of the direct and sensitized photoreactions is attributed to changes in intramolecular hemiketal formation in fullerenol.

JOURNAL Dual Nitrate Isotopes in Dry Deposition: Utility for Partitioning Nox Source Contributions to Landscape Nitrogen Deposition 12/11/2009
Elliott, E. M., C. Kendall, E. B. Boyer, D. A. Burns, G. LEAR, H. E. GOLDEN, K. Harlin, A. Bytnerowicz, T. J. Butler, AND R. Glatz. Dual Nitrate Isotopes in Dry Deposition: Utility for Partitioning Nox Source Contributions to Landscape Nitrogen Deposition. Journal of Geophysical Research - Biogeosciences. American Geophysical Union, Washington, DC, 114(G04020):1-15, (2009).
Abstract: Dry deposition is a major component of total nitrogen deposition and thus an important source of bioavailable nitrogen to ecosystems. However, relative to wet deposition, less is known regarding the sources and spatial variability of dry deposition. This is in part due to difficulty in measuring dry deposition and associated deposition velocities. Passive sampling techniques offer new potential for improving our understanding of the spatial distribution and sources of dry deposition. We present dual nitrate isotopes (δ15N and (δ18O) in actively and passively collected dry and wet deposition across the high deposition region of Ohio, New York, and Pennsylvania. Isotopes in actively collected dry deposition, including particulate nitrate and gaseous nitric acid, are compared with those in wet nitrate deposition and surrounding NOx emission sources.

JOURNAL Extending the Diffuse Layer Model of Surface Acidity Behavior: III. Estimating Bound Site Activity Coefficients 11/15/2009
LOUX, N. T. Extending the Diffuse Layer Model of Surface Acidity Behavior: III. Estimating Bound Site Activity Coefficients. CHEMICAL SPECIATION AND BIOAVAILABILITY. Science and Technology Letters, 21(4):233-244, (2009).
Abstract: Although detailed thermodynamic analyses of the 2-pK diffuse layer surface complexation model generally specify bound site activity coefficients for the purpose of accounting for those non-ideal excess free energies contributing to bound site electrochemical potentials, in application these terms are ignored based on one or more of the following assumptions: (1) bound site activity coefficients cancel out in the mass action quotients; (2) bound sites display ideal behaviour; and/or (3) these energies are already included in the exponential Boltzmann terms. In this work it is demonstrated that the bound site charging energy terms discussed in the two previous papers in this series have both conceptual and computational analogies to the charging energy contribution to the activity coefficients obtained from the Debye-Huckel Limiting Law.

JOURNAL Analysis of Perfluorinated Chemicals in Sludge: Method Development and Initial Results 11/06/2009
Yoo, H., J. W. WASHINGTON, T. JENKINS, AND L. LIBELO. Analysis of Perfluorinated Chemicals in Sludge: Method Development and Initial Results. JOURNAL OF CHROMATOGRAPHY A. Elsevier Science Ltd, New York, NY, 1216(45):7831-7839, (2009).
Abstract: A fast, rigorous method was developed to maximize the extraction efficacy for ten perfluorocarboxylic acids and perfluorooctanesulfonate from wastewater-treatment sludge and to quantitate using liquid chromatography, tandem-mass spectrometry (LC/MS/MS). First, organic solvents were tested for extraction efficiency, including acetonitrile (ACN), methanol (MeOH), isopropanol (IPA), tetrahydrofuran (THF), and 50/50 ACN/MeOH (v/v). Among the extractants tested, 50/50 ACN/MeOH yielded the best results for our combined criteria of extraction efficacy and solvent-handling convenience. Second, chemical pretreatment prior to solvent extraction was tested with sodium hydroxide (NaOH), potassium hydroxide (KOH), hydrochloric acid (HCl), and potassium persulfate (K2S2O8). Pretreatment with NaOH and HCl effectively recovered additional PFCs from the sludge, but KOH and K2S2O8 digestion were less effective than no pretreatment. Third, cleanup methods were investigated with solid-phase extraction using HLB (hydrophilic-lipophilic balanced) and WAX (weak-anion exchange) stationary phases, and with ion-pairing. The HLB stationary phase yielded a slight edge over the other two cleanup strategies in terms of recoverable PFCs and chromatographic separation. Finally, the appropriateness of isotopically labeled PFCs for quantitating unlabeled PFCs using isotopic dilution in complex sludge extracts was evaluated by comparison to results obtained with the standard-addition method. A National Institute of Standards and Technology (NIST) domestic sludge (CRM 2781) was analyzed using our finalized method and compared with previously reported results.

JOURNAL Riparian Sediment Delivery Ratio: Stiff Diagrams and Artifical Neural Networks 11/01/2009
Ssegane, H., E. W. Tollner, AND S. C. MCCUTCHEON. Riparian Sediment Delivery Ratio: Stiff Diagrams and Artifical Neural Networks. Transactions of the ASABE. AMERICAN SOCIETY OF AGRICULTURAL AND BIOLOGICAL ENGINEERS, ST. JOSEPH, MI, 52(6):1885-1893, (2009).
Abstract: Various methods are used to estimate sediment transport through riparian buffers and grass jilters with the sediment delivery ratio having been the most widely applied. The U.S. Forest Service developed a sediment delivery ratio using the stiff diagram and a logistic curve to integrate some of the factors influencing sediment delivery heuristically. This study independently tested the Forest Service sediment delivery ratio contrasted with artificial neural networks to represent the multiple nonlinearities between important factors and sediment delivery. The Forest Service sediment delivery ratio was not adequate when compared to published sediment yields from 30 small experimental buffers from three countries, including four forested buffers. However, artificial neural networks gave estimates of the delivery ratio that were highly correlated to the observations. The 30 buffer observations produced such good estimates of the sediment delivery ratio with both seven and five buffer parameters that this study suggests that as few as 30 sediment yield observations can be the basis for applying neural networks to interpolate the complex, multiple nonlinearities of hydrology and sediment transport on riparian buffers.

JOURNAL The Poplar Gt8e and Gt8f Glycosyltransferases Are Functional Orthologs of Arabidopsis Parvus Involved in Gulcuronoxylan Biosynthesis 11/01/2009
Lee, C., Q. TENG, W. Huang, R. Zhong, AND Z. H. Ye. The Poplar Gt8e and Gt8f Glycosyltransferases Are Functional Orthologs of Arabidopsis Parvus Involved in Gulcuronoxylan Biosynthesis. Plant and Cell Physiology. Oxford Journals, 50(11):1982-1987, (2009).
Abstract: The poplar GT8E and GT8F glycosyltransferases have previously been shown to be associated with wood formation, but their roles in the biosynthesis of wood components are not known. Here, we show that PoGT8E and PoGT8F are expressed in vessels and fibers during wood formation and their encoded proteins are predominantly located in the endoplasmic reticulum. We demonstrate that expression of PoGT8E and PoGT8F in the Arabidopsis parvus mutant rescues the defects in the content and structure of glucuronoxylan conferred by the parvus mutation. These findings suggest that PoGT8E and PoGT8F are involved in glucuronoxylan biosynthesis during wood formation in poplar.

JOURNAL Degradability of An Acrylate-Linked, Fluorotelomer Polymer in Soil 09/01/2009
WASHINGTON, J. W., J. J. ELLINGTON, T. JENKINS, J. J. EVANS, H. Yoo, AND S. C. Hafner. Degradability of An Acrylate-Linked, Fluorotelomer Polymer in Soil. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 43(17):6617-6623, (2009).
Abstract: Fluorotelomer polymers are used in a broad array of products in modern societies worldwide and, if they degrade at significant rates, potentially are a significant source of perfluorooctanoic acid (PFOA) and related compounds to the environment. To evaluate this possibility, we incubated an acrylate-linked fluorotelomer polymer in soil microcosms and monitored the microcosms for possible fluorotelomer (FT) and perfluorinated-compound (PFC) degradation products using GC/MS and LC/MS/MS. This polymer scavenged FTs and PFCs aggressively necessitating development of a multistep extraction using two solvents. Aged microcosms accumulated more FTs and PFCs than were present in the fresh polymer indicating polymer degradation with a half-life of about 870−1400 years for our coarse-grained test polymer. Modeling indicates that more-finely grained polymers in soils might have half-lives of about 10−17 years assuming degradation is surface-mediated. In our polymer-soil microcosms, PFOA evidently was lost with a half-life as short as 130 days, possibly by polymer-catalyzed degradation. These results suggest that fluorotelomer-polymer degradation is a significant source of PFOA and other fluorinated compounds to the environment.

JOURNAL Colloidal Properties of Aqueous Fullerenes: Isoelectric Points and Aggregation Kinetics of C60 and C60 Derivatives 09/01/2009
BOUCHARD, D., XIN MA, AND C. W. Isaacson. Colloidal Properties of Aqueous Fullerenes: Isoelectric Points and Aggregation Kinetics of C60 and C60 Derivatives. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 43(17):6597-6603, (2009).
Abstract: Aqueous colloidal suspensions of C-60 (aqu/C-60) and the C-60 derivatives PCBM ([6,6]-phenyl C-61-butyric acid methyl ester) and the corresponding butyl and octyl esters, PCBB and PCBO (aqu/PCB-R, where R is an alkyl group), were produced by stirring in double deionized water for 5 months. Kinetically stable fullerene aggregates were formed using this procedure that ranged in intensity-averaged hydrodynamic diameter (D-h) from 193 +/- 2 nm (95% C.L.) for aqu/C-60 to 259 +/- 6 nm for aqu/PCBO. Measured zeta potentials (zeta) were < -50 mV, and the isoelectric points (pf) were <1.0 for all of the aqu/fullerenes. Time-resolved dynamic light scattering (TRDLS) was used to measure aqu/fullerene D-h change with time and as a function of background solution ionic strength. The critical coagulation concentration (CCC) values for the aqu/PCB-R fullerenes were significantly higher than that of aqu/C-60, indicating that the phenyl alkyl ester moieties of the aqu/PCB-R fullerenes were impeding the aggregation process.

JOURNAL Contrasting Influence of Nadph and a Nadph-Regenerating System on the Metabolism of Carbonyl-Containing Compounds in Hepatic Microsomes 09/01/2009
MAZUR, C. S., J. F. KENNEKE, M. GOLDSMITH, AND C. BROWN. Contrasting Influence of Nadph and a Nadph-Regenerating System on the Metabolism of Carbonyl-Containing Compounds in Hepatic Microsomes. DRUG METABOLISM AND DISPOSITION. American Society for Pharmacology and Experimental Therapeutics, Bethesda, MD, 37(9):1801-1805, (2009).
Abstract: Carbonyl containing xenobiotics may be susceptible to NADPH-dependent cytochrome P450 (P450) and carbonyl-reduction reactions. In vitro hepatic microsome assays are routinely supplied NADPH either by direct addition of NADPH or via an NADPH-regenerating system (NRS). In contrast to oxidative P450 transformations, which occur on the periphery of a microsome vesicle, intraluminal carbonyl reduction depends on transport of cofactors across the endoplasmic reticulum (ER) membrane into the lumen. Glucose 6-phosphate, a natural cofactor and component of the NRS matrix, is readily transported across the ER membrane and facilitates intraluminal NADPH production, whereas direct addition of NADPH has limited access to the lumen. In this study, we compared the effects of direct addition of NADPH and use of an NRS on the P450-mediated transformation of propiconazole and 11 beta-hydroxysteroid dehydrogenase type 1 (HSD1) carbonyl reduction of cortisone and the xenobiotic triadimefon in hepatic microsomes. Our results demonstrate that the use of NADPH rather than NRS can underestimate the kinetic rates of intraluminal carbonyl reduction, whereas P450-mediated transformations were unaffected. Therefore, in vitro depletion rates measured for a carbonyl-containing xenobiotic susceptible to both intraluminal carbonyl reduction and P450 processes may not be properly assessed with direct addition of NADPH. In addition, we used in silico predictions as follows: 1) to show that 11 beta-HSD1 carbonyl reduction was energetically more favorable than oxidative P450 transformation; and 2) to calculate chemical binding score and the distance between the carbonyl group and the hydride to be transferred by NADPH to identify other 11 beta-HSD1 substrates for which reaction kinetics may be underestimated by direct addition of NADPH.

JOURNAL Spatial Variability of Nitrate Concentrations Under Diverse Conditions in Tributaries to a Lake Watershed 08/15/2009
GOLDEN, H. E., E. W. Boyer, M. G. Brown, S. T. PURUCKER, AND R. H. Germain. Spatial Variability of Nitrate Concentrations Under Diverse Conditions in Tributaries to a Lake Watershed. JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION. American Water Resources Association, Middleburg, VA, 45(4):945-962, (2009).
Abstract: Nitrate-nitrogen (NO3-N) concentrations in stream water often respond uniquely to changes in inter-annual (e.g., biological N uptake, precipitation) conditions in individual catchments. In this paper, we assess (1) how the spatial distribution of NO3-N concentrations varies across a dense network of non-nested catchments and (2) how relationships between multiple landscape factors (within whole catchments and hydrologically-sensitive areas of the catchments) and stream NO3-N are expressed under a variety of annual conditions.

JOURNAL Fish Assemblage Patterns as a Tool to Aid Conservation in the Olifants River Catchment (East), South Africa 07/15/2009
RASHLEIGH, B., D. Hardwick, AND D. Roux. Fish Assemblage Patterns as a Tool to Aid Conservation in the Olifants River Catchment (East), South Africa. Water SA. Water Research Commission, PRETORIA, South Africa, 35(4):517-524, (2009).
Abstract: South Africa has committed to address freshwater conservation at the catchment scale, using a combination of landscape-level and species-level features as surrogates of freshwater biodiversity. Here we examined fishes in the Olifants catchment, where multiple anthropogenic pressures affect streams. We analyzed patterns in fish assemblage data for 87 sites, using data from the National River Health Programme and a series of landscape environmental variables. Multivariate ordination and cluster analysis identified six distinct assemblage types, which were separated by altitude and human influence, primarily dryland cropping and dams. Classification and regression tree analysis was performed for selected species and for species diversity. In the upper reaches of the catchment, a faunal shift occurred with land use change, from more sensitive species to more tolerant species. The fish assemblage of the middle section of the catchment was not unique, but it did support one species, C. pretoriae, that could be considered a focal species. The low elevation, high-yield section of the catchment supported the most species, however, diversity increased in association with dams, through the addition of flow-tolerant species, so diversity may not be an optimal conservation target for this system. Rather, a series of indicators will be necessary to track and measure conservation success in the Olifants catchment.

JOURNAL Mechanistic Approach to Understanding the Toxicity of the Azole Fungicide Triadimefon to a Nontarget Aquatic Insect and Implications for Exposure Assessment 07/15/2009
KENNEKE, J. F., C. S. MAZUR, K. A. Kellock, AND J. P. Overmyer. Mechanistic Approach to Understanding the Toxicity of the Azole Fungicide Triadimefon to a Nontarget Aquatic Insect and Implications for Exposure Assessment. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 43(14):5507-5513, (2009).
Abstract: We utilized mechanistic and stereoselective based in vitro metabolism assays and sublethal exposures of triadimefon to gain insight into the extent of carbonyl reduction and the toxic mode of action of triadimefon with black fly (Diptera: Simuliidae) larvae.

JOURNAL Analysis of Fluorotelomer Alcohols in Soils: Optimization of Extraction and Chromatography 07/10/2009
ELLINGTON, J. J., J. W. WASHINGTON, J. J. EVANS, T. M. JENKINS, S. C. Hafner, AND M. NEILL. Analysis of Fluorotelomer Alcohols in Soils: Optimization of Extraction and Chromatography. JOURNAL OF CHROMATOGRAPHY A. Elsevier Science Ltd, New York, NY, 1216(28):5347-5354, (2009).
Abstract: This article describes the development of an analytical method for the determination of fluorotelomer alcohols (FTOHs) in soil. The sensitive and selective determination of the telomer alcohols was performed by extraction with mthyl tert-butyl ether (MTBE) and analysis of the extract using gas chromatography with detection and quantification by mass spectrometry operated in the positive chemical ionization mode.

JOURNAL Evaluating Uncertainty in Integrated Environmental Models: A Review of Concepts and Tools 06/17/2009
MATOTT, L. S., J. E. BABENDREIER, AND S. T. PURUCKER. Evaluating Uncertainty in Integrated Environmental Models: A Review of Concepts and Tools. WATER RESOURCES RESEARCH. American Geophysical Union, Washington, DC, 45:W06421, (2009).
Abstract: This paper reviews concepts for evaluating integrated environmental models and discusses a list of relevant software-based tools. A simplified taxonomy for sources of uncertainty and a glossary of key terms with standard definitions are provided in the context of integrated approaches to environmental assessment. These constructs provide a reference point for cataloging 65 different model evaluation tools. Each tool is described briefly (in the auxiliary material) and is categorized for applicability across seven thematic model evaluation methods. Ratings for citation count and software availability are also provided, and a companion Web site containing download links for tool software is introduced. The paper concludes by reviewing strategies for tool interoperability and offers guidance for both practitioners and tool developers.

JOURNAL Water Analysis: Emerging Contaminants and Current Issues (2009 Review) 06/15/2009
RICHARDSON, S. D. Water Analysis: Emerging Contaminants and Current Issues (2009 Review). Analytical Chemistry. American Chemical Society, Washington, DC, 81(12):4645-4677, (2009).
Abstract: This biennial review covers developments in Water Analysis for Emerging Environmental Contaminants over the period of 2007-2008. A few significant references that appeared between January and February 2009 are also included. Analytical Chemistry’s current policy is to limit reviews to a maximum of 250 significant references and to mainly focus on new trends. Even with a more narrow focus, only a small fraction of the quality research publications could be discussed. This was especially true this year with all the growth in the pharmaceutical area, where my entire allotment of 250 references could have been used in this one section alone. As a result, as with the previous review on Water Analysis in 2007, this review will not be comprehensive, but will highlight new areas and discuss representative papers in the areas of focus. This review on Water Analysis focuses only on water measurements and applications, but includes other methodologies besides mass spectrometry.

JOURNAL Down-Regulation of Pogt47c Expression in Poplar Results in a Reduced Glucuronoxylan Content and An Increased Wood Digestibility By Cellulase 06/01/2009
Lee, C., Q. TENG, W. Huang, R. Zhong, AND Z. H. Ye. Down-Regulation of Pogt47c Expression in Poplar Results in a Reduced Glucuronoxylan Content and An Increased Wood Digestibility By Cellulase. Plant and Cell Physiology. Oxford Journals, 50(6):1075-1089, (2009).
Abstract: Xylan is the second most abundant polysaccharide in dicot wood. Unraveling the biosynthetic pathway of xylan is important not only for our understanding of the process of wood formation but also for our rational engineering of wood for biofuel production. Although several glycosyltransferases are implicated in glucuronoxylan (GX) biosynthesis in Arabidopsis, whether their close orthologs in woody tree species are essential for GX biosynthesis during wood formation has not been investigated. In fact, no studies have been reported to evaluate the effects of alterations in secondary wall-associated glycosyltransferases on wood formation in tree species. In this report, we demonstrate that PoGT47C, a poplar glycosyltransferase belonging to family GT47, is essential for the normal biosynthesis of GX and the normal secondary wall thickening in the wood of the hybrid poplar Populus alba × tremula. RNA interference (RNAi) inhibition of PoGT47C resulted in a drastic reduction in the thickness of secondary walls, a deformation of vessels and a decreased amount of GX in poplar wood. The transgenic wood was found to yield more glucose by cellulase digestion than the wild-type wood, indicating that the GX reduction in wood reduces the recalcitrance of wood to cellulase digestion. Together, these results provide direct evidence demonstrating that the PoGT47C glycosyltransferase is essential for normal GX biosynthesis in poplar wood and that GX modification could improve the digestibility of wood cellulose by cellulase.

JOURNAL A Direct Cell Quenching Method for Cell-Culture Based Metabolomics 06/01/2009
TENG, Q., W. HUANG, T. W. COLLETTE, D. R. EKMAN, AND C. TAN. A Direct Cell Quenching Method for Cell-Culture Based Metabolomics. Metabolomics. Springer, New York, NY, 5(2):199-208, (2009).
Abstract: A crucial step in metabolomic analysis of cellular extracts is the cell quenching process. The conventional method first uses trypsin to detach cells from their growth surface. This inevitably changes the profile of cellular metabolites since the detachment of cells from the extracellular matrix alters their physiology. This conventional method also includes time consuming wash/centrifuge steps after trypsinization, but prior to quenching cell activity. During this time, a considerable portion of intracellular metabolites are lost, rendering the conventional method less than ideal for application to metabolomics. We report here a novel sample preparation method for metabolomics applications using adherent mammalian cells, which eliminates the time consumption and physiological stress of the trypsinization and wash/centrifuge steps. This new method was evaluated in the study of metabolic changes caused by 17α-ethynylestradiol (EE2) in estrogen receptor (ER)-positive MCF-7 and ER-negative MDA-MB-231 human breast cancer cell lines using NMR spectroscopy. The results demonstrated that our direct cell quenching method is rapid, effective, and exhibits greater metabolite retention, providing an increase of approximately a factor of 50 compared to the conventional method.

JOURNAL Endocrine Disrupting Chemicals in Fish: Developing Exposure Indicators and Predictive Models of Effects Based on Mechanism of Action 05/05/2009
ANKLEY, G. T., D. C. BENCIC, M. BREEN, T. W. COLLETTE, R. CONOLLY, N. Denslow, S. W. EDWARDS, D. R. EKMAN, K. M. JENSEN, J. M. LAZORCHAK, D. MARTINOVIC, D. H. MILLER, E. Perkins, E. F. Orlando, N. Garcia-Reyero, D. L. VILLENEUVE, R. WANG, AND K. Watanabe. Endocrine Disrupting Chemicals in Fish: Developing Exposure Indicators and Predictive Models of Effects Based on Mechanism of Action. AQUATIC TOXICOLOGY. Elsevier Science Ltd, New York, NY, 92(3):168-178, (2009).
Abstract: In this paper we provide an overview and illustrative results from a large, integrated project that assesses the effects of endocrine-disrupting chemicals (EDCs) on two small fish models, the fathead minnow (Pimephales promelas) and zebrafish (Danio rerio). For this work a systems-based approach is being used to delineate toxicity pathways for 12 model EDCs with different known or hypothesized toxic MOA. The studies employ a combination of state-of-the-art genomic (transcriptomic, proteomic, metabolomic), bioinformatic and modeling approaches, in conjunction with whole animal testing protocols, to develop response linkages across biological levels of organization. This understanding forms the basis for predictive approaches for species, endpoint and chemical extrapolation. Although our project is focused specifically on EDCs in fish, we believe that the basic conceptual approach has utility for systematically assessing exposure and effects of chemicals with other MOA across a variety of biological systems.

JOURNAL The F8h Glycosyltransferase Is a Functional Paralog of Fra8 Involved in Glucuronoxylan Biosynthesis in Arabidopsis 04/01/2009
Lee, C., Q. TENG, W. Huang, R. Zhong, AND Z. H. Ye. The F8h Glycosyltransferase Is a Functional Paralog of Fra8 Involved in Glucuronoxylan Biosynthesis in Arabidopsis. Plant and Cell Physiology. Oxford Journals, 50(4):812-827, (2009).
Abstract: The FRAGILE FIBER8 gene was previously shown to be required for the biosynthesis of the reducing end tetrasaccharide sequence of glucuronoxylan (GX) in Arabidopsis thaliana. Here, we demonstrate that F8H, a close homolog of FRA8, is a functional ortholog of FRA8 involved in GX biosynthesis. The F8H gene is preferentially expressed in xylem cells, in which the secondary walls contain abundant amount of GX, and the F8H protein is targeted to Golgi where GX is synthesized. Overexpression of F8H in the fra8 mutant completely complemented the fra8 mutant phenotypes including the secondary wall thickness of fibers and vessels, vessel morphology, GX content, and the abundance of the reducing end tetrasaccharide sequence of GX, indicating that F8H shares the same biochemical function as FRA8. Although the f8h mutant alone did not show any detectable cell wall defects, the f8h/fra8 double mutant exhibits an additional reduction in cell wall xylose level, a more severe deformation of vessels, and an extreme retardation in plant growth compared with the fra8 mutant. Together, our findings suggest that F8H and FRA8 are functional orthologs and they function redundantly in GX biosynthesis during secondary wall formation in Arabidopsis.

JOURNAL Childhood Asthma and Environmental Exposures at Swimming Pools: State of the Science and Research Recommendations 04/01/2009
Weisel, C. P., S. D. RICHARDSON, B. Nemery, G. Aggazzotti, E. Baraldi, E. R. Blatchley III, B. C. Blount, K. H. Carlsen, P. A. Eggleston, F. H. Frimmel, M. Goodman, G. Gordon, S. A. Grinshpun, D. Heederik, M. Kogevinas, J. S. LaKind, M. J. Nieuwenhuijsen, F. C. Piper, AND S. A. Sattar. Childhood Asthma and Environmental Exposures at Swimming Pools: State of the Science and Research Recommendations. ENVIRONMENTAL HEALTH PERSPECTIVES. National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC, 117(4):500-507, (2009).
Abstract: Recent studies have explored the potential for swimming pool disinfection byproducts (DBPs) which are respiratory irritants to cause asthma in young children. While these studies raise concerns, gaps still exist in our knowledge regarding the exact causal agents and mechanisms for reported associations. A multidisciplinary Workshop was held with the goal of developing a research agenda that would improve our understanding of children’s exposure to DBPs and biologics at swimming pools and whether such exposures are associated with new onset childhood asthma.

JOURNAL Transformation of Organophosphorus Pesticides in the Presence of Aqueous Chlorine: Kinetics, Pathways, and Structure-Activity Relationships 04/01/2009
DUIRK, S. E., L. M. Desetto, AND G. M. Davis. Transformation of Organophosphorus Pesticides in the Presence of Aqueous Chlorine: Kinetics, Pathways, and Structure-Activity Relationships. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 43(7):2335-2340, (2009).
Abstract: The fate of organophosphorus (OP) pesticides in the presence of aqueous chlorine was investigated under simulated drinking water treatment conditions. Intrinsic rate coefficients were found for the reaction of hypochlorous acid (kHOCl,OP) and hypochlorite ion (kOCl,OP) for eight OP pesticides. The reaction of hypochlorous acid (HOCl) with each OP pesticide was relatively rapid near neutral pH. A model was developed to predict the transformation of OP pesticides in the presence of chlorinated oxidants. With hydrolysis rate coefficients, the transformation of OP pesticides under drinking water treatment conditions was found to be adequately predicted. The structure-activity relationships and model developed here could be used by risk assessors to determine exposure to OP pesticides and their transformation products in potable water.

JOURNAL Application of Ecosystem-Scale Fate and Bioaccumulation Models to Predict Fish Mercury Response Times to Changes in Atmospheric Deposition 03/10/2009
KNIGHTES, C. D., E. SUNDERLAND, M. C. BARBER, J. M. JOHNSTON, AND R. B. AMBROSE. Application of Ecosystem-Scale Fate and Bioaccumulation Models to Predict Fish Mercury Response Times to Changes in Atmospheric Deposition. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 28(4):881-893, (2009).
Abstract: Management strategies for controlling anthropogenic mercury emissions require understanding how ecosystems will respond to changes in atmospheric mercury deposition. Process-based mathematical models are valuable tools for informing such decisions, because measurement data often are sparse and cannot be extrapolated to investigate the environmental impacts of different policy options. Here, we bring together previously developed and evaluated modeling frameworks for watersheds, water bodies, and food web bioaccumulation of mercury. We use these models to investigate the timescales required for mercury levels in predatory fish to change in response to altered mercury inputs. We model declines in water, sediment, and fish mercury concentrations across five ecosystems spanning a range of physical and biological conditions, including a farm pond, a seepage lake, a stratified lake, a drainage lake, and a coastal plain river. Results illustrate that temporal lags are longest for watershed-dominated systems (like the coastal plain river) and shortest for shallow water bodies (like the seepage lake) that receive most of their mercury from deposition directly to the water surface. All ecosystems showed responses in two phases: A relatively rapid initial decline in mercury concentrations (20–60% of steady-state values) over one to three decades, followed by a slower descent lasting for decades to centuries. Response times are variable across ecosystem types and are highly affected by sediment burial rates and active layer depths in systems not dominated by watershed inputs. Additional research concerning watershed processes driving mercury dynamics and empirical data regarding sediment dynamics in freshwater bodies are critical for improving the predictive capability of process-based mercury models used to inform regulatory decisions.

JOURNAL Profiling Lipid Metabolites Yields Unique Information on Sex-and Time-Dependent Responses of Fathead Minnows (pimephales Promelas) Exposed to 17α-Ethynylestradiol 03/01/2009
EKMAN, D. R., Q. TENG, D. L. VILLENEUVE, M. D. KAHL, K. M. JENSEN, E. J. DURHAN, G. T. ANKLEY, AND T. W. COLLETTE. Profiling Lipid Metabolites Yields Unique Information on Sex-and Time-Dependent Responses of Fathead Minnows (pimephales Promelas) Exposed to 17α-Ethynylestradiol. Metabolomics. Plenum Press, New York, NY, 5(1):22-32, (2009).
Abstract: Alterations in hepatic lipid profiles of fathead minnows (FHM) exposed to the synthetic estrogen 17α-ethynylestradiol (EE2) were determined using 1H-NMR spectroscopy-based metabolite profiling. The exposures were conducted using either 10 ng/l or 100 ng/l EE2 via a continuous flow water delivery system. Livers were collected at 1, 4, and 8 days of the exposure and 8 days after the chemical was removed from the water (i.e. an 8 day depuration). The exposure resulted in a number of sex-specific changes in lipid profiles that were also highly time dependent. Those metabolites most affected by exposure included phosphatidylcholine, diglycerides, triglycerides and cholesterol. In addition, changes in the length and degree of unsaturation of hepatic fatty acids were observed. Lipid profiles in plasma for fish collected on the 4th day of exposure were also analyzed in order to provide further insights into changes observed in hepatic metabolite changes. Using validated partial least-squares discriminant analysis (PLS-DA), the response trajectories of the male liver lipid profiles at both exposure concentrations were compared. This analysis indicated that the males exposed to the low concentration of EE2 (10 ng/l) were largely able to recover from the exposure once the chemical was removed from the water. Conversely, the males exposed to the high concentration (100 ng/l) did not appear to recover from the exposure despite the 8 day depuration.

JOURNAL Spectral Relative Standard Deviation: A Practical Benchmark in Metabolomics 03/01/2009
Parsons, H. M., D. R. EKMAN, T. W. COLLETTE, AND M. R. Viant. Spectral Relative Standard Deviation: A Practical Benchmark in Metabolomics. ANALYST. Royal Society of Chemistry, Cambridge, Uk, 134(3):478-485, (2009).
Abstract: Metabolomics datasets, by definition, comprise of measurements of large numbers of metabolites. Both technical (analytical) and biological factors will induce variation within these measurements that is not consistent across all metabolites. Consequently, criteria are required to assess the reproducibility of metabolomics datasets that are derived from all the detected metabolites. Here we calculate spectrum-wide relative standard deviations (RSD; also termed coefficient of variation, CV) for ten metabolomics datasets, spanning a variety of sample types from mammals, fish, invertebrates and a cell line, and display them succinctly as boxplots. We demonstrate multiple applications of spectral RSDs for characterising technical as well as inter-individual biological variation: for optimising metabolite extractions, comparing analytical techniques, investigating matrix effects, and comparing biofluids and tissue extracts from single and multiple species for optimising experimental design. Technical variation within metabolomics datasets, recorded using one- and two-dimensional NMR and mass spectrometry, range from 1.6% to 20.6% (reported as the median spectral RSD). Inter-individual biological variation is typically larger, ranging from as low as 7.2% for tissue extracts from laboratory housed rats to 58.4% for fish plasma. In addition, for some of the datasets we confirm that the spectral RSD values are largely invariant across different spectral processing methods, such as baseline correction, normalisation and binning resolution. In conclusion, we propose spectral RSDs and their median values contained herein as practical benchmarks for metabolomics studies.

JOURNAL Time-Frequency Analysis of Beach Bacteria Variations and Its Implication for Recreational Water Quality Modeling 02/15/2009
GE, Z. AND W. E. FRICK. Time-Frequency Analysis of Beach Bacteria Variations and Its Implication for Recreational Water Quality Modeling. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 43(4):1128-1133, (2009).
Abstract: This paper explores the potential of time-frequency wavelet analysis in resolving beach bacteria concentration and possible explanatory variables across multiple time scales with temporal information still preserved. The wavelet scalograms of E. coli concentrations and the explanatory variables observed at Huntington Beach, Ohio in 2006 clearly reveal well-defined short-time patterns of different periods, timings, phases, and durations, exhibiting nonstationarity and nonlinearity in all time series. If linear regression models must be used rather than more advanced nonlinear models, these observed characteristics in the time series favor modeling data over shorter durations such that nonstationarity can be reduced and recent temporal patterns in the variations adequately represented. In comparison, a model based on multiple years of data may perform poorly in response to local patterns and cause excessive model error. To further justify the statistical robustness of short-period regression models (typically weekly models), we discuss the stability of the first and second order moments. We found that models based on a duration that is 5/3 times the period of the local largest-scale time pattern can generally attain stable moments.

JOURNAL Elucidating the Role of Electron Shuttles in Reductive Transformations in Anaerobic Sediments 02/15/2009
Zhang, H. AND E. J. WEBER. Elucidating the Role of Electron Shuttles in Reductive Transformations in Anaerobic Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 43(4):1042-1048, (2009).
Abstract: Model studies have demonstrated that electron shuttles (ES) such as dissolved organic matter (DOM) can participate in the reduction of organic contaminants; however, much uncertainty exists concerning the significance of this solution phase pathway for contaminant reduction in natural systems. To compare the identity and reactivity of ES in anaerobic sediments with those in model systems, two chemical probes (4-cyano-4'-aminoazobenzene (CNAAzB) either free or covalently bound to glass beads) were synthesized that allowed for differentiation between surface-associated and solution-phase electron-transfer processes. The feasibility of these chemical probes were demonstrated in abiotic model systems (Fe(II)/Fe(III) oxide) and biotic model systems (Fe(II)/Fe(III) oxide or river sediment amended with S. putrefaciens strain cells). Experiments in the abiotic systems revealed that the addition of model hydroquinones and chemically reduced DOM increased reduction rates of free CNAAzB, whereas no enhancement in reactivity was observed with the addition of model quinones or DOM. Bound CNAAzB was also reduced by model hydroquinones and reduced DOM-but not by model quinones and untreated DOM-in the abiotic model systems, indicating that Fe(II)/Fe(III) oxides do not function as a bulk reductant for the reduction of ES. Addition of model quinones or untreated DOM to the biotic models systems with sediment increased reduction rates of bound CNAAzB, which correlated well with the dissolved organic carbon content. In natural sediment slurries, reduction rates of bound CNAAzB correlated well with parameters for organic carbon (OC) content of both sediments and supernatants. Our results support a scenario in which reducible organic contaminants will compete with iron oxides for the electron flow generated by the microbially mediated oxidation of organic carbon and subsequent reduction of quinone functional groups associated with DOM.

JOURNAL Formation of Aqueous Suspensions of Fullerenes 01/15/2009
MA, X. AND D. BOUCHARD. Formation of Aqueous Suspensions of Fullerenes. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 43(2):330-336, (2009).
Abstract: Colloidal suspensions of C60, C70 and a derivative of C60, PCBM ([6,6]-Phenyl C61-butyric acid methyl ester) were produced by extended mixing in water. We examined the contribution of background solution chemistry (pH, ionic strength) on the formation kinetics of colloidal suspensions in terms of mass, aggregate size and zeta potential. These parameters were also compared between free-settling and filtered treatments. Results indicated that all three fullerenes were highly negatively charged in aqueous systems, that it took a finite time to reach kinetically-stable suspensions, and that suspension formation was pH and ionic strength dependent. With isoelectric points approaching zero, the suspensions were generally stable at pH >3. The results indicate that it is critical to state the condition under which the formation of aqueous fullerene suspensions occur when employing such suspensions to evaluate environmental toxicity or fate and transport of fullerenes.

JOURNAL International Nmr-Based Environmental Metabolomics Intercomparison Exercise 01/01/2009
Viant, M. R., D. Bearden, J. G. Bundy, I. Burton, T. W. COLLETTE, D. R. EKMAN, V. Ezernieks, T. Karakach, C. Y. Lin, S. Rochfort, J. S. De Ropp, Q. TENG, R. S. Tjeerdema, J. Walter, AND H. Wu. International Nmr-Based Environmental Metabolomics Intercomparison Exercise. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 43(1):219-225, (2009).
Abstract: Several fundamental requirements must be met so that NMR-based metabolomics and the related technique of metabonomics can be formally adopted into environmental monitoring and chemical risk assessment. Here we report an intercomparison exercise which has evaluated the effectiveness of 1H NMR metabolomics to generate comparable datasets from environmentally derived samples. It focuses on laboratory practice that follows sample collection and metabolite extraction, specifically the final stages of sample preparation, NMR data collection (500, 600 and 800 MHz), data processing and multivariate analysis. Seven laboratories have participated from the USA, Canada, UK and Australia, generating a total of ten datasets. Phase 1 comprised the analysis of synthetic metabolite mixtures, while Phase 2 investigated European flounder (Platichthys flesus) liver extracts from clean and contaminated sites. Overall, the comparability of datasets from the participating laboratories was good. Principal components analyses (PCA) of the individual datasets yielded ten highly similar scores plots for the synthetic mixtures, with a comparable result for the liver extracts. Furthermore, the same metabolic biomarkers that discriminated fish from clean and contaminated sites were discovered by all the laboratories. PCA of the combined datasets showed excellent clustering of the multiple analyses. These results demonstrate that NMR-based metabolomics can generate data that are sufficiently comparable between laboratories to support its continued evaluation for regulatory environmental studies.

NEWSLETTER ARTICLE Anticipating Environmental Impacts of Future Fuels 05/15/2009
WEAVER, J. W. Anticipating Environmental Impacts of Future Fuels. In: LUSTLine, New England Interstate Water Pollution Control Commission, Lowell, MA(61):5-6, (2009).
Abstract: Automotive fuels are composed of hundreds of compounds and the formulations aren’t uniform; they vary geographically and seasonally and sometimes specifically in response to regulatory requirements. As a result, very few state underground storage tank (UST) regulators know what is in the fuel stream at a service station or bulk plant in their state. Consequently, difficulties abound in anticipating which compounds to sample, choosing analytical methods and eventually selecting technologies for effective remediation in the case of a release. We face the new challenge of determining the correct approach to protecting human health and the environment that includes prioritization of chemicals based on toxicity, fate, and transport in the subsurface. This article touches on some basic new fuel-related concerns in leaking underground storage tank (LUST) site assessment and remediation, particularly those associated with ethanol in gasoline.

PAPER IN NON-EPA PROCEEDINGS Modeled Watershed Runoff Associated With Variations in Precipitation Data, With Implications for Contaminant Fluxes: Initial Results 10/15/2009
GOLDEN, H. E., C. D. KNIGHTES, E. COOTER, AND R. L. DENNIS. Modeled Watershed Runoff Associated With Variations in Precipitation Data, With Implications for Contaminant Fluxes: Initial Results. In Proceedings, Planning for an Uncertain Future—Monitoring, Integration, and Adaptation. Third Interagency Conference on Research in the Watersheds, Estes Park, CO, September 08 - 11, 2008. United States Geological Survey, Denver, CO, 129-135, (2009).
Abstract: Precipitation is one of the primary forcing functions of hydrologic and watershed fate and transport models; however, in light of advances in precipitation estimates across watersheds, data remain highly uncertain. A wide variety of simulated and observed precipitation data are available for use in regional air quality models and watershed fate and transport models. Although these single media models can potentially link together to estimate contaminant loadings issuing from watersheds, questions remain concerning how precipitation data from diverse sources used within each model affect water and contaminant mass balances. We assess how two sets of spatially distributed precipitation data, simulated at 12km grid and 36km grid resolutions, affect runoff simulated from a spatially distributed grid-based mercury watershed model that has been calibrated using observed precipitation data. We focus on two headwater catchments in the Cape Fear River Basin, North Carolina. Our initial results suggest that precipitation data simulated at a coarse resolution (e.g., 36km grid) decreases the efficiency and goodness-of-fit of modeled runoff, but this is watershed specific. Variations in the response to coarse resolution precipitation potentially results from differences in the size and within stream structural modifications of each watershed. These initial results are assessed within the context a broader project that will also evaluate the effects of radar and empirically-estimated precipitation data sets on modeled runoff and variations in watershed contaminant loading resulting from these diverse precipitation inputs.

PAPER IN NON-EPA PROCEEDINGS Using Stream Discharge as a Predictor of Biotic Health in the Upper Oconee Watershed 04/29/2009
Sterling, J. L., B. RASHLEIGH, B. L. Nuse, AND R. Katz. Using Stream Discharge as a Predictor of Biotic Health in the Upper Oconee Watershed. In Proceedings, Georgia Water Resources Conference, Athens, GA, April 27 - 29, 2009. Georgia Institute of Technology, Atlanta, GA, 1-5, (2009).
Abstract: Drought is viewed typically as an issue of water quantity, but drought also likely has strong effects on water quality in streams. These effects may occur via increased pollutant and nutrient concentrations and stream water temperature, as well as reductions in instream habitat. Many aquatic macroinvertebrate taxa are sensitive to changes in water chemistry, and streams with degraded water quality are often characterized by low macroinvertebrate diversity. A previous study by the Upper Oconee Watershed Network related the Georgia Adopt-A-Stream biotic index for macroinvertebrates to water chemistry (Kominoski et al. 2007), but did not consider the effects of stream discharge, which also potentially influences index scores. We used long-term datasets on biotic indices of water quality in the upper Oconee River watershed to determine whether variation in biotic indices is associated with periods of extreme low flow. We used multiple measures of flow (including seasonal means, minima, maxima, and variability in discharge) from USGS gauge data to examine patterns in the Georgia Adopt-A-Stream macroinvertebrate index for seven tributaries of the North and Middle Oconee Rivers in Clarke County, Georgia. We found that the inclusion of flow variables improved the prediction of macroinvertebrate index scores, compared to a model including only chemical variables, and that a positive response occurred to mean flow in the preceding season. We infer from our results that site-specific flow variability may be structuring benthic macroinvertebrate communities in urban streams in the upper Oconee River basin, and may be important to consider when using indices for bioassessment throughout the state of Georgia.

PAPER IN NON-EPA PROCEEDINGS An Assessment of Fecal Contamination in Rural Streams Impacted By Litter Applications 04/27/2009
Lee, Y. J. AND M. MOLINA. An Assessment of Fecal Contamination in Rural Streams Impacted By Litter Applications. In Proceedings, 2009 Georgia Water Resources Conference, Athens, GA, April 27 - 29, 2009. University of Georgia, Athens, GA, 7.7.2, (2009).
Abstract: The objective of this study was to evaluate transport of fecal materials into streams located in farms containing pastures with the presence (AH and DH) and absence (DF) of cattle using various source-specific PCR assays. All pasture sites were fertilized with composted chicken litter. The riparian zones of the streams varied in vegeta-tion cover and type. General Bacteroidales (Bac32F) signatures were detected in 96.2% of the samples across all streams. Ruminant-specific Bacteroidales marker (CF128F) was detected in AH (56.9%) and DF (82.1%); however, chicken-specific metagenomic markers were not detected, indicating the absence or below-detection-limit-level of chicken fecal contamination in the streams. A bird-specific metagenomic marker, CP1-1, was only detected in one of the cattle pastures (AH) following broiler litter application combined with a rain event. Mul-tiple linear regressions (MLR) revealed that temperature and turbidity positively correlated with enterococcal density in AH and DF. No significant explanatory variable for enterococcal density was found in DH. This study suggests that although the general fecal marker was identified frequently in the streams, indicating a constant input of fecal material, the source of the contamination varied. This variability seem to be dependent on a variety of factors, such as the quality of the stream buffer strip, quality of the composted fertilizer, and the distance of the cattle to the stream.

PRESENTATION Simulated Response of Mercury and Nitrogen to Land Management and Land Use Change in a Large River Basin 12/14/2009
GOLDEN, H. E. AND C. D. KNIGHTES. Simulated Response of Mercury and Nitrogen to Land Management and Land Use Change in a Large River Basin. Presented at 2009 American Geophysical Union Fall Meeting, San Francisco, CA, December 14 - 18, 2009.
Abstract: Increases in nitrogen cascading from headwater systems to coastal waterways and bioaccumulation of mercury in aquatic ecosystems have become primary environmental concerns in recent decades. Studies assessing the effects of land use or climate change on water quality in large river basins, however, typically focus on one particular chemical constituent (e.g., inorganic nitrogen) or a group of similarly reacting chemicals (e.g., nutrients). Rarely have long-term studies or management decisions simultaneously focused on excess nitrogen, a nutrient linked to coastal eutrophication, and methyl mercury (MeHg), a neurotoxin linked to multiple human health effects. This is unfortunate, as strategies focusing exclusively on reducing nitrogen in surface waters might counteract efforts to attenuate mercury, and vice versa. For example, the presence of extensive riparian wetland areas within a watershed provides a sink for nitrogen by promoting denitrification, but these anoxic conditions may also enhance mercury methylation, thereby potentially increasing methyl mercury fluxes to surface waters. On the other hand, nutrient management strategies may concurrently reduce mercury exposure. We simulate concurrent long-term changes in loadings of total mercury (THg), MeHg, and nitrate-nitrogen (NO3-N) using a spatially distributed grid-based watershed mercury model (GBMM) linked to a simple watershed nitrogen process model, both of which receive inputs from a regional atmospheric model (CMAQ). We assess change in the fluxes of each, in response to modifications in land use practices and land cover change, and discuss potential implications for targeting nitrogen and mercury reductions in large river basins. Our work focuses on linking regional watershed and atmospheric models in the Cape Fear River Basin, North Carolina. This large river basin is located in the Coastal Carolinas, one of the place-based research initiatives within the broader US Environmental Protection Agency (USEPA) Ecosystems Services Research Program (ESRP). The ESRP focuses on modeling and evaluating the long-term effects of diverse stressors on nutrient and contaminant fluxes and consequently on ecosystem services, particularly in estuarine systems. Our findings provide a window to the temporally linked dynamics of mercury and nitrate in response to land cover and management practices, and may therefore guide future watershed management.

PRESENTATION Anion-Dependent Aggregate Formation and Charge Behavior of Colloidal Fullerenes (N-C60) 12/14/2009
Mukherjee, B. AND J. W. WEAVER. Anion-Dependent Aggregate Formation and Charge Behavior of Colloidal Fullerenes (N-C60). Presented at 2009 American Geophysical Union Fall Meeting, San Francisco, CA, December 14 - 18, 2009.
Abstract: The fate and transport of colloidal fullerenes (n-C60) in the environment is likely to be guided by electrokinetic and aggregation behavior. In natural water bodies inorganic ions exert significant effects in determining the size and charge of n-C60 nanoparticles. Although the effects of cations on the behavior n-C60 NPs have been studied extensively; studies on the effect of anions are relatively few and thus were the focus of our investigation.

PRESENTATION Comparing (Semi-) Analytic Solutions Used to Model the Impact of Deep Carbon Injection on the Displacement and Pressurization of the Resident Brine 12/14/2009
Bandilla, K. W. AND S. R. KRAEMER. Comparing (Semi-) Analytic Solutions Used to Model the Impact of Deep Carbon Injection on the Displacement and Pressurization of the Resident Brine. Presented at 2009 American Geophysical Union Fall Meeting, San Francisco, CA, December 14 - 18, 2009.
Abstract: Injection of carbon dioxide into deep saline formations is seen as one possible technology for mitigating carbon emissions from utilities. The safety of the sequestered carbon dioxide is the focus of many studies with leakage through faults or abandoned wells as some of the main failure mechanisms. The focus of this study is on the displacement of resident brine and the resulting changes in pressure due to the injection of large volumes of super-critical phase carbon dioxide into the subsurface. The movement of brine becomes important if it travels vertically and reaches an existing or potential underground source of drinking water where an increase in salt content may threaten the viability of the drinking water source. Vertical displacement of brine may occur slowly through confining layers, or more rapidly through faults and abandoned wells. This presentation compares several (semi-) analytic solutions to determine their applicability to the problem of brine pressurization and displacement. The goal is to find ranges of formation parameters (e.g., formation seal conductivity, distance to lateral boundary, … ) for which simplifying assumption are justifiable Each simplification in the conceptual model (e.g., neglecting the lateral boundary turns a bounded domain into an infinite one) leads to a simpler (semi-) analytic solution. The process involves a solution hierarchy from the most complex solution down to the basic Theis solution. A software tool-kit implementing several (semi-) analytic solutions was developed for this study to facilitate the comparison of the solutions.

PRESENTATION Ecosystem Services Research for Coastal Wetlands 11/25/2009
RASHLEIGH, B. Ecosystem Services Research for Coastal Wetlands. Presented at Klaipeda University, Coastal Research and Planning Institute, Klaipeda, LITHUANIA, November 25, 2009.
Abstract: Presentation on ecosystem services research for coastal wetlands presented at Klaipeda University, Lithuania.

PRESENTATION Water, Climate, and Ecosystem Services 11/20/2009
RASHLEIGH, B. Water, Climate, and Ecosystem Services. Presented at Cultural Dialogue and Personality International Conference, Klaipeda, LITHUANIA, November 20, 2009.
Abstract: Scientific meeting presentation.

PRESENTATION Enantioselective Toxicity and Biotransformation of Fipronil in the Fathead Minnow (Pimephales Promelas) 11/19/2009
Baird, S., A. W. GARRISON, J. K. AVANTS, AND M. C. Black. Enantioselective Toxicity and Biotransformation of Fipronil in the Fathead Minnow (Pimephales Promelas). Presented at SETAC North America 30th Annual Meeting, New Orleans, LA, November 19 - 23, 2009.
Abstract: Fipronil is a relatively new chiral phenylpyrazole insecticide used to control both agricultural and household invertebrate pests. Fipronil is applied as a racemate, or equal mixture, of its two enantiomers. As regulations on older pesticides increase, production and application of fipronil is expected to increase, leading to increased inputs into aquatic environments. Although a number of toxicity studies have demonstrated acute and chronic enantioselective toxicity of fiprinil in aquatic invertebrates, data on enantioselective toxicity in fish is limited. We conducted three 7-day aquatic toxicity experiments to determine the acute and subchronic toxicity of the fipronil racemate and each enantiomer to larval fathead minnows (Pimephales promelas). Acute (96-hr) LC50s for the fipronil racemate and each enantiomer were not significantly different. However, enantioselective toxicity was observed in fathead minnow exposures with longer exposure durations (7-d), with increased toxicity of the racemate (7-day LC50 = 191 µg/L) and (+) enantiomer (7-day LC50 = 207 µg/L) observed compared to the (-) enantiomer (7-day LC50 = 312 µg/L). Reduced fish growth was also observed in fish exposed to the (+) enantiomer and racemate, compared to the (-) enantiomer. Linear regression of concentration vs. fish weights at 7 days revealed significantly increased slopes for the (+) enantiomer and racemate versus the (-) enantiomer (p<0.05). Curiously, for both chronic endpoints toxicity of the racemate and (+) enantiomer was not significantly different, even though the racemate contains 50% of the (+) enantiomer and 50% of the less toxic (-) enantiomer. Metabolic processes could potentially change the enantiomeric fraction present in the organism, so that fathead minnows selectively transform and eliminate the (-) enantiomer, increasing the proportion of the more toxic (+) enantiomer in the racemic exposure. An on-going bioaccumulation experiment where fathead minnows are exposed to fipronil under realistic sediment:water exposure conditions should allow us to test this hypothesis.

PRESENTATION Asymmetric Flow-Field Flow Fractionation (Af4) of Aqueous C60 Aggregates With Dynamic Light Scattering Size and LC-MS 11/19/2009
Isaacson, C. W., XIN MA, S. Lee, AND D. BOUCHARD. Asymmetric Flow-Field Flow Fractionation (Af4) of Aqueous C60 Aggregates With Dynamic Light Scattering Size and LC-MS. Presented at SETAC North America 30th Annual Meeting, New Orleans, LA, November 19 - 23, 2009.
Abstract: Current methods for the size determination of nanomaterials in aqueous suspension include dynamic or static light scattering and electron or atomic force microscopy techniques. Light scattering techniques are limited by poor resolution and the scattering intensity dependence on particle size. Microscopy techniques are limited by sample preparation artifacts and are cumbersome when multiple samples must be analyzed. Asymmetric flow-field flow fractionation (AF4) is an open channel size separation technique in which particles are separated by difference in diffusion coefficients. AF4 can operate under an array of solution conditions, including a large range of ionic strengths and surfactants. In addition, AF4 has the unique capability of separating particles ranging from 1 to 500 nm in hydrodynamic diameter (Dh). Presented herein is the first report of the size fractionation of aqueous C60 aggregates (aqu/C60) by AF4 coupled in line with dynamic light scattering (DLS) for size determination. Surfactants, which are commonly used to enhance particle stability, were avoided as they may alter particle size. Additionally, to determine the mass of C60 in each size range, fractions were collected from the AF4 and the amounts of C60 were quantified using LC-APPI-MS. As determined by DLS aqu/C60 ranged in size from 80-260 nm in Dh which was verified by the analysis of fractions by DLS in batch mode as well as by TEM. Of the total mass of aqua/C60, 7.7 ± 6.9 % of the aqua/C60 mass had Dh less than 80 nm, while 58 ± 32 % had Dh between 80-150 nm and 14 ± 9.2 % of the aqua/C60 were between 150-260 nm in Dh. Deposition was observed in the AF4 channel as 79 ± 5.7 % of the initial aqua/C60 eluted from the AF4 channel. The use of membranes with hydrophobic and hydrophilic functionalities did not reduce the amount of aqu/C60 deposited. As predicted by AF4 theory, detector flow splitting increased the detector response, although increasing the split ratio beyond 80% of the channel flow resulted in elution of aqu/C60 in the split flow stream.

PRESENTATION Characterization of a Wide Array of Fluorinated Organic Compounds in Contaminated Soils 11/19/2009
Yoo, H., J. W. WASHINGTON, T. M. JENKINS, J. J. ELLINGTON, AND L. LIBELO. Characterization of a Wide Array of Fluorinated Organic Compounds in Contaminated Soils. Presented at SETAC North America 30th Annual Meeting, New Orleans, LA, November 19 - 23, 2009.
Abstract: Herein we report the results of analyses on the concentrations of perfluorinated compounds (PFCs) and fluorotelomer alcohols (FTOHs) in soils from a site that has been impacted by human activities. Soil samples were collected from several locations that had been impacted and one background field that had not been impacted. All samples were extracted and analyzed for perfluorocarboxylic acids ranging from C6 to C14 including C8 (PFOA), the 8:2 and 10:2 unsaturated acids, and the perfluorosulfonates C4, C6, C7 and C8 (PFOS) by liquid-chromatography, tandem mass spectrometry (LC/MS/MS); most of these analytes were quantified using a mass-labeled matrix internal standard of the same chemical species and the 13C8-PFOA internal-standard recovery averaged about 90%. Samples also were extracted and analyzed for FTOHs (F(CF2)xC2H4OH) where x = 6, 8, 10, 12 and 14 perfluorinated carbons, the sec-FTOHs (F(CF2)yCH(CH3)OH) where y = 7, 9, 11 and 13 perfluorinated carbons, and the 8:2 fluorotelomer acrylate by gas chromatography, mass spectrometry (GC/MS); these analytes were quantified using a 2H213C2-10:2FTOH matrix internal standard and the 2H213C2-8:2FTOH internal-standard recovery averaged about 110%. In the absence of authentic standards for the sec-FTOHs, they were quantified using their respective y-1 standard curves and their identity was confirmed by: 1) GC/MS, scan spectra, in positive chemical ionization mode, of the MTBE extract that contained the expected [M + 1]+ ion; 2) the ion corresponding to loss of m/z 38 (HF + H2O) from the [M + 1]+ ion; and 3) by derivitization with trimethylsilylimidazole. We will report absolute concentration ranges for the analytes as well as selected patterns between homologues, between the PFCs and FTOHs, and any correlations between target analytes and soil properties.

PRESENTATION Male Fathead Minnow Urine-Based Metabolomics for Assessing Impacts of Chemical Stressors 11/19/2009
EKMAN, D. R., Q. TENG, K. M. JENSEN, M. D. KAHL, D. MARTINOVIC, D. VILLENEUVE, G. T. ANKLEY, AND T. W. COLLETTE. Male Fathead Minnow Urine-Based Metabolomics for Assessing Impacts of Chemical Stressors. Presented at SETAC North America 30th Annual Meeting, New Orleans, LA, November 19 - 23, 2009.
Abstract: We have developed the potential for profiling metabolites in urine from male fathead minnows (Pimephales promelas) to assess chemical exposures, using nuclear magnetic resonance (NMR) spectroscopy. Both one dimensional (1D) and two dimensional (2D) NMR spectroscopy was used for the assignment of metabolites in urine from unexposed fish. Because fathead minnow urine is dilute, we lyophilized these samples prior to analysis. Furthermore, 1D 1H-NMR spectra of unlyophilized urine from unexposed male fathead minnow and Sprague-Dawley rat have been acquired to qualitatively compare rat and fish metabolite profiles and to provide an estimate of the total urinary metabolite pool concentration difference. As a small proof-of-concept study, lyophilized urine samples from male fathead minnows exposed to three different concentrations of the antiandrogen vinclozolin were analyzed by 1D 1H-NMR to assess exposure-induced changes. Through a combination of principal components analysis (PCA) and measurements of 1H-NMR peak intensities, several metabolites were identified as changing with statistical significance in response to exposure. Among those changes occurring in response to exposure to the highest concentration (450 µg/L) of vinclozolin were large increases in taurine, lactate, acetate, and formate. These increases coincided with a marked decrease in hippurate, a combination potentially indicative of hepatotoxicity. Subsequently, we have used the same methodology to study the impacts of a chemical mixture of a model androgen, trenbolone (TRB) and a model anti-androgen, cyproterone acetate (CA). Results demonstrate that, as expected, the presence of TRB (500 ng/L) decreases the impact that CA has on the male fish when the exposure level of CA is high (200 µg/L). But, interesting, the presence of TRB (500 ng/L) increases the impact of CA when the exposure to CA is below the level that causes decreased plasma testosterone concentrations (20 µg/L). The results of these investigations clearly demonstrate the utility of an NMR-based approach for assessing chemical exposures in male fathead minnow, using urine collected from individual fish.

PRESENTATION Metabolomics in Small Fish Toxicology: Assessing the Impacts of Model Edcs 11/19/2009
COLLETTE, T. W., Q. TENG, K. M. JENSEN, M. D. KAHL, D. MARTINOVIC, D. VILLENEUVE, G. T. ANKLEY, AND D. R. EKMAN. Metabolomics in Small Fish Toxicology: Assessing the Impacts of Model Edcs. Presented at SETAC North America 30th Annual Meeting, New Orleans, LA, November 19 - 23, 2009.
Abstract: Although lagging behind applications targeted to human endpoints, metabolomics offers great potential in environmental applications, including ecotoxicology. Indeed, the advantages of metabolomics (relative to other ‘omic techniques) may be more tangible in ecotoxicology because there is often not a sequenced genome available for ecologically relevant species. We are conducting metabolomics studies on small fish, such as the fathead minnow, that are used both as model organisms in ecotoxicology research, and in regulatory testing programs. Our goal is to use information from these studies to meet EPA’s mission to protect ecosystems from potentially harmful effects of chemical pollutants. For example, as part of a project involving a large, interdisciplinary team of scientists from US government, academia, and industry, we are integrating transcriptomic, proteomic, and metabolomic data to describe endocrine disruption in the fathead minnow. We seek to understand how chemical exposures are linked through early molecular changes to whole-organism adverse outcomes and, ultimately, to changes in population status. To achieve this goal, a systems-based approach is being used to define toxicity pathways for model chemicals with well defined modes of action within the hypothalamic-pituitary-gonadal (HPG) axis of the fathead minnow. We will describe the unique role that metabolomics plays in this important environmental applications.

PRESENTATION Toxicity of Triadimefon Racemate and Enantiomers to Black Fly Larvae 11/19/2009
Kellock, K., J. Overmyer, A. W. GARRISON, AND J. K. AVANTS. Toxicity of Triadimefon Racemate and Enantiomers to Black Fly Larvae. Presented at SETAC North America 30th Annual Meeting, New Orleans, LA, November 19 - 23, 2009.
Abstract: Triadimefon is a conazole fungicide commonly used for commercial and agricultural fungal control on trees, ornamentals and fruits. It is a chiral compound, existing as R-(-) and S-(+) enantiomers and used as the racemate. This is of interest since the triadimefon enantiomers can have varying degrees of toxicity to non-target organisms. Results of earlier 48 hr LC50 tests at pH 7.6, reported as the median with fiducial limits, showed that triadimefon racemate (+/-) is toxic to the black fly larvae. In the current study, the triadimefon racemate and its enantiomers were evaluated separately to determine their respective 48 hr LC50 values to black fly (Diptera: Simuliidae) larvae using an orbital shaker toxicity bioassay. Previous research had shown that triadimefon enantiomerizes in water at near neutral pHs, so the pH was maintained at near 5 to prevent enantiomer conversion. Preliminary data at pH 5 indicates the (-) enantiomer to be two-fold more toxic than the racemate, while the (+) enantiomer LC50 falls in between the racemate and (-) values. Future work will focus on final LC50 toxicity assessments of triadimefon, its enantiomers, and its metabolites, as well as investigations into triadimefon metabolic pathways and mechanisms relative to black fly larvae.

PRESENTATION Integrated Modeling for Watershed Ecosystem Services Assessment and Forecasting 11/09/2009
BARBER, M. C., J. E. BABENDREIER, R. B. AMBROSE, M. J. CYTERSKI, H. E. GOLDEN, C. D. KNIGHTES, S. R. KRAEMER, G. F. LANIAK, N. T. LOUX, R. S. PARMAR, L. M. PRIETO, S. T. PURUCKER, B. RASHLEIGH, L. A. SUAREZ, M. E. TRYBY, G. WHELAN, AND K. L. WOLFE. Integrated Modeling for Watershed Ecosystem Services Assessment and Forecasting. Presented at Millennium Conference 2009: Water-Ecosystem Services, Drought, and Environmental Justice, Athens, GA, November 09 - 12, 2009.
Abstract: Regional scale watershed management decisions must be informed by the science-based relationship between anthropogenic activities on the landscape and the change in ecosystem structure, function, and services that occur as a result. We applied process-based models that represent watershed loading, mercury processing, instream water quality, habitat suitability, and fish community dynamics, linked together in a feed-forward design to address these issues within the Albemarle-Pamlico watershed in Virginia/North Carolina. Additional features of this approach are an automated method to retrieve data from national databases (Data for Environmental Modeling, D4EM), and a framework for assessing and communicating uncertainties that are relevant to the assessment, including natural variability, environmental data measurement error, analysis conceptualization, and model structure. We focused on the services of water quantity and quality, as well as fisheries habitat, productivity, and bioaccumulation. This approach allows us to examine the effects of alternative climate and land-use scenarios on services, and to statistically analyze results and extrapolate to the regional scale, with uncertainty characterization. We have found that for multimedia model development, specific problems drive technology development, and technology integration leads science integration.

PRESENTATION Global Metabolomics of Breast Cancer Cells 11/05/2009
TENG, Q. Global Metabolomics of Breast Cancer Cells. Presented at The Chicago Regional NMR Meeting, Chicago, IL, November 05 - 08, 2009.
Abstract: Scientific meeting presentation.

PRESENTATION Ecosystem Services Provided By Stream Fishes 11/03/2009
RASHLEIGH, B., L. M. PRIETO, S. T. PURUCKER, L. A. SUAREZ, AND M. C. BARBER. Ecosystem Services Provided By Stream Fishes. Presented at 2009 Mid-Atlantic Stream Restoration Conference, Morgantown, WV, November 03 - 05, 2009.
Abstract: Stream fish provide important services to people, including recreation and food, regulation of ecosystem processes, and aesthetic benefits. If the services provided by fish in different streams can be measured, then they can be valued and considered in restoration decisions. We developed predictive habitat models for stream fish species that are indicators for different services in the Albemarle-Pamlico basin. These hierarchical models use environmental predictors from the NHD Plus dataset and account for natural differences in ecoregion and river drainage. We found that different services have distinct responses to stressors, and not all species are important service providers. The services approach to aquatic ecosystems may not protect all stream fish species, and thus should be carefully assessed for use in restoration.

PRESENTATION Potential for Metabolomics-Based Markers of Exposure:Encouraging Evidence from Studies Using Model Organisms 11/01/2009
COLLETTE, T. W., D. R. EKMAN, AND Q. TENG. Potential for Metabolomics-Based Markers of Exposure:Encouraging Evidence from Studies Using Model Organisms. Presented at 19th Annual International Society of Exposure Science Conference, Minneapolis, MN, November 01 - 05, 2009.
Abstract: Genomic techniques (transcriptomics, proteomics, and metabolomics) have the potential to significantly improve the way chemical risk is managed in the 21st century. Indeed, a significant amount of research has been devoted to the use of these techniques to screen chemicals for hazardous effects. However, changes in transcripts, proteins, and endogenous metabolites may, in some cases, be more-certain indicators of chemical exposures than of apical chemical effects. Nonetheless, these powerful new techniques have rarely been applied as markers of exposure. Metabolomics may be a particularly powerful genomic tool for developing markers for both human and ecological exposures. For human exposures, it is important to note that metabolomics can be conducted effectively on biofluids that can be collected non-invasively from humans (e.g., urine, breath condensate, saliva) regardless of the ultimate disposition of the anthropogenic chemical. For ecological exposures, it is important to note that metabolomics can be conducted effectively without the need for a sequenced genome, and that metabolism is often conserved across species. We will illustrate here the advantages of metabolomics for developing markers of exposure, using results from studies with, e.g., fathead minnows, rodents and cell-cultures exposed to a variety of chemical stressors.

PRESENTATION Source-to-Outcome Microbial Exposure and Risk Modeling Framework 11/01/2009
WHELAN, G., M. E. TRYBY, AND J. SOLLER. Source-to-Outcome Microbial Exposure and Risk Modeling Framework. Presented at 19th Annual International Society of Exposure Science Conference, Minneapolis, MN, November 01 - 05, 2009.
Abstract: A Quantitative Microbial Risk Assessment (QMRA) is a computer-based data-delivery and modeling approach that integrates interdisciplinary fate/transport, exposure, and impact models and databases to characterize potential health impacts/risks due to pathogens. As such, a QMRA exercise fits well with multimedia modeling paradigms that have been widely exercised in the chemical and radionuclide communities, using software system architectures, like the Framework for Risk Analysis in Multimedia Environmental Systems (FRAMES). FRAMES provides the infrastructure to seamlessly link disparate models and databases, providing an assessor with the ability to construct an appropriate conceptual site model from a host of modeling choices, so a myriad number of QMRA analyses can be supported and reproduced. The Microbial Risk Assessment Interface Tool (MRA-IT) is an open-source, integrated software environment for performing an application of the pathogen exposure, intake, dose, and risk, containing several key components, including, but not limited to, pathogen specification, exposure scenario identification, and dose-response relationships. The current version of MRA-IT lacks upstream fate and transport components that produce pathogen and indicator concentrations in the water column prior to exposure. The MRA-IT is seamlessly linked, using FRAMES, with upstream fate and transport models. The final package is a software technology framework that focuses on linkages across the source-to-outcome continuum and provides an illustrative demonstration of microbial fate and transport, exposure routes and scenarios, intake volumes, dose, and risk computations.

PRESENTATION A Systems Approach to Assessing Risk: the Role of Metabolism Research in Describing and Predicting Exposure 11/01/2009
KENNEKE, J. F., C. S. MAZUR, A. W. GARRISON, C. K. CUNNINGHAM, AND R. D. Miller. A Systems Approach to Assessing Risk: the Role of Metabolism Research in Describing and Predicting Exposure. Presented at 19th Annual International Society of Exposure Science Conference, Minneapolis, MN, November 01 - 05, 2009.
Abstract: An important component of assessing risk is defining the exposure of a chemical stressor to a target organism. Often the chemical stressor is assumed to be a single compound even when it is comprised of different stereoisomers (e.g., pyrethroids and 1,2,4-triazole fungicides), which possess different physical, chemical and toxicological properties. Additional uncertainties in exposure assessment arise when the chemical undergoes transformation inside the organism, especially when the transformation is organ, species, and/or gender specific. Thus, a “simple” exposure scenario of a single chemical may ultimately involve multiple stressors (i.e., stereoisomers and metabolites) resulting in multiple internal exposures. Our research focuses on defining the internal exposure of chemical stressors in organisms. We utilize in vitro and in vivo metabolism assays, specific enzyme inhibitors, purified enzymes, and molecular docking to elucidate the kinetics and mechanisms of xenobiotic metabolism to deconvolute simple exposure scenarios. For example, we have shown that the exposure of triadimefon to liver microsomes from eight vertebrate species resulted in the formation of triadimenol in all cases; however, the exposure scenario is actually more complex. Triadimefon metabolism occurs via the reduction of a prochiral carbonyl that yields a unique set of four triadimenol stereoisomers for each species. The stereoisomers have different toxicities and degrees of binding with endogenous receptors (e.g., enzymes involved in steroidogenesis and nuclear receptors), which could impact the mode-of-action of triadimefon. The implications of this for risk assessment are worth considering because triadimefon exposure to human liver microsomes produces a significantly higher percentage of the more toxic stereoisomers than rat (i.e., rat results extrapolated to human may underpredict risk). Examples of the (1) stereoselective and gender specific metabolism of 1,2,4-traizole fungicides, (2) organ and species specific metabolism of bisphenol A, and (3) stereoselective metabolism of pyrethroids for use in exposure reconstruction will also be presented.

PRESENTATION Simulating the Stability of Colloidal Amorphous Iron Oxide in Natural Waters 11/01/2009
LOUX, N. T. Simulating the Stability of Colloidal Amorphous Iron Oxide in Natural Waters. Presented at 19th Annual Conference of the International Society of Exposure Science, Minneapolis, MN, November 01 - 05, 2009.
Abstract: Anecdotal evidence suggests that there are more than 800 commercial products containing manufactured nanomaterials in commercial production and that this number is expected to increase in an exponential fashion. Unfortunately, existing standardized test guidelines designed to assess the environmental mobility of commercial products are not likely to be directly applicable to insoluble nanomaterial suspensions in natural waters. This work describes findings from an ongoing effort designed to assess the utility of the historical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal particle stability when used in conjunction with legacy Diffuse Layer (DLM) and Triple Layer (TLM) electrostatic surface complexation models. Due to the availability of data, colloidal amorphous iron oxide was selected as a test substrate and the likelihood of its forming stable suspensions over a pH range of 4 to 10 was assessed in simulated 0.7 M seawater, 0.1 M diluted seawater, world average river water, continental U.S. average groundwater and 50th percentile midwestern U.S. rainwater. Findings from the work included: 1) legacy surface complexation models are likely to overestimate the diffuse layer potential (and stability) of smaller, nanosized colloidal particles, 2) both DLM and TLM models predict unstable iron oxide suspensions in the 0.7 and 0.1 M seawater systems and both models predict stability in most of the rainwater simulations, 3) the DLM diffuse layer potential estimates generally exceeded the TLM values and there was not agreement concerning stability assessments in the simulated river and groundwaters, 4) the major ions present in natural waters are likely to have a profound impact on system-dependent diffuse layer potentials and 5) findings from both models were at least qualitatively in agreement with observations reported in the literature.

PRESENTATION Forecasting of Services Provided By Stream Ecosystems: Integrated Modeling 10/29/2009
BARBER, M. C., R. B. AMBROSE, J. E. BABENDREIER, M. J. CYTERSKI, H. E. GOLDEN, C. D. KNIGHTES, S. R. KRAEMER, G. F. LANIAK, N. T. LOUX, R. S. PARMAR, L. M. PRIETO, S. T. PURUCKER, B. RASHLEIGH, L. A. SUAREZ, M. E. TRYBY, G. WHELAN, AND K. L. WOLFE. Forecasting of Services Provided By Stream Ecosystems: Integrated Modeling. Presented at 2009 Mid-Atlantic Stream Restoration Conference, Morgantown, WV, November 03 - 05, 2009.
Abstract: Scientific meeting poster.

PRESENTATION Predicting the Total Standing Stock of Resident Salmonids in Forested Streams of the Willamette River Basin a Macroecological Approach 10/19/2009
MCGARVEY, D. J. AND J. M. JOHNSTON. Predicting the Total Standing Stock of Resident Salmonids in Forested Streams of the Willamette River Basin a Macroecological Approach. Presented at 2nd Annual Ecosystem Services Research Program Annual Meeting, Athens, GA, October 19 - 23, 2009.
Abstract: Scientific meeting poster.

PRESENTATION Meeting in Dallas: Emerging Environmental Contaminants: What's New 10/19/2009
RICHARDSON, S. D. Meeting in Dallas: Emerging Environmental Contaminants: What's New. Presented at 19th Annual Quality Assurance Conference , Dallas, TX, October 19 - 23, 2009.
Abstract: Scientific meeting presentation. Much has been achieved in the way of environmental protection over the last 30 years. However, as we learn more, new concerns arise (including potential adverse health effects, bioaccumulation, and widespread distribution). This presentation will discuss emerging environmental contaminants that the U.S. Environmental Protection Agency (EPA) and other agencies are currently concerned about. Emerging contaminants include pharmaceuticals, perfluorooctanoic acid (PFOA) and other perfluorinated compounds, nanomaterials, drinking water disinfection by-products (DBPs), polybrominated diphenyl ether (PBDE) flame retardants, pesticide degradation/reaction products, perchlorate, hormones, algal toxins, sunscreens/UV filters, benzotriazoles, dioxane, naphthenic acids, and pathogens. In addition, a recent study of the finding of a new artificial sweetener, sucralose, in surface waters from 27 countries in Europe (up to ppb levels) will be discussed.

PRESENTATION Fish Metapopulation Modeling 10/19/2009
RASHLEIGH, B., D. WHITE, AND JOE L. EBERSOLE. Fish Metapopulation Modeling. Presented at 2nd Annual Ecosystem Services Research Program Annual Meeting, Athens, GA, October 19 - 23, 2009.
Abstract: Scientific meeting poster.

PRESENTATION Integrated Multi-Disciplinary Modeling Capabilities 10/16/2009
WHELAN, G. Integrated Multi-Disciplinary Modeling Capabilities. Presented at EPA Office of Water, Washington, DC, October 16, 2009.
Abstract: Scientific meeting presentation.

PRESENTATION Parallel Computing and Model Evaluation for Environmental Systems: An Overview of the Supermuse and Frames Software Technologies 10/14/2009
BABENDREIER, J. E. Parallel Computing and Model Evaluation for Environmental Systems: An Overview of the Supermuse and Frames Software Technologies. Presented at Annual Public Meeting and Workshop of the Interagency Steering Committee on Multimedia Environmental Models (ISCMEM), Rockville, MD, October 13 - 15, 2009.
Abstract: ERD’s Supercomputer for Model Uncertainty and Sensitivity Evaluation (SuperMUSE) is a key to enhancing quality assurance in environmental models and applications. Uncertainty analysis and sensitivity analysis remain critical, though often overlooked steps in the development and evaluation of computer models. In land management for example, while there is a high potential for exposure of humans and ecosystems to chemicals released into the environment, the degree to which this potential is realized is to some degree uncertain. SuperMUSE helps address various computational tasks associated with various quantitative techniques used to evaluate models and modeling systems (e.g., uncertainty analysis (UA), sensitivity analysis (SA). A specific SuperMUSE interface was developed for FRAMESV2, and is known as the FUITasker. An extensive suite of additional “Systems” tools are also now available in FRAMES Version 2. Together with SuperMUSE 1.0, the software sets can be used for conducting various UA/SA/PE studies. A discussion is presented with various examples of the software, along with key aspects of design. The software additions and joint capabilities allow leverage at both single desktop and cluster scales.

PRESENTATION Integrating Data, Models, Uncertainty Analysis Methods, and Super Computing to Facilitate Modern Environmental Assessments 10/13/2009
LANIAK, G. F. Integrating Data, Models, Uncertainty Analysis Methods, and Super Computing to Facilitate Modern Environmental Assessments. Presented at Annual Public Meeting and Workshop of the Interagency Steering Committee on Multimedia Environmental Models (ISCMEM), Rockville, MD, October 13 - 15, 2009.
Abstract: Scientific meeting presentation.

PRESENTATION Meeting in Atlanta: Iodo-Dbp Formation from the Reaction of Chlorinated Oxidants With X-Ray Contrast Media in the Presence of Natural Organic Matter 10/07/2009
RICHARDSON, S. D., S. E. DUIRK, C. Lindell, C. Cornelison, T. A. Ternes, AND M. J. Plewa. Meeting in Atlanta: Iodo-Dbp Formation from the Reaction of Chlorinated Oxidants With X-Ray Contrast Media in the Presence of Natural Organic Matter. Presented at Atlanta-Athens Mass Spectrometry Discussion Group Annual Symposium, Atlanta, GA, October 07, 2009.
Abstract: Scientific meeting presentation.

PRESENTATION Oceanic Methane Concentrations in Three Mexican Regions 10/07/2009
Macias-Zamora, J. V., K. Castro-Morales, R. A. BURKE, AND F. Saro-Rivera. Oceanic Methane Concentrations in Three Mexican Regions. Presented at First Mexican Carbon Symposium, Ensenada, Baja California, MEXICO, October 07 - 09, 2009.
Abstract: The atmospheric concentration of methane has increased significantly over the last several decades. Methane is an important greenhouse gas, and it is important to better quantify methane sources and sinks. Dissolved methane in the ocean is produced by biological and hydrothermal processes: however, the distribution, variability and role of oceanic methane in the global carbon cycle is poorly understood. We present the first measurements of dissolved methane concentrations in seawater from three oceanic regions in Mexico. Our goals were to determine the methane distribution, evaluate the contributions of natural and anthropogenic processes to its formation, and evaluate the potential contribution of these regions to the global methane inventory. Discrete seawater samples were collected at different depths during different sampling periods from 2004 to 2006. The study areas are: the northern part of the Gulf of California and the nearshore Pacific Ocean from the USA border to Ensenada and from south of Ensenada to Vizcaino Bay. The dissolved methane content was quantified by the phase equilibration method, and methane fluxes were calculated with a simple equation that incorporates the sea-air concentration gradient and a windspeed-dependent gas transfer coefficient. The northern Gulf of California has shown higher fluxes from the ocean to the atmosphere compared to the other regions. The methane in this region is probably produced by biological processes associated with high marine productivity rather than hydrothermal processes.

PRESENTATION Application of Wasp8 Hg Module for Modeling Mercury Transport and Transformation Along the Sudbury River, Massachusetts 10/06/2009
KNIGHTES, C. D. Application of Wasp8 Hg Module for Modeling Mercury Transport and Transformation Along the Sudbury River, Massachusetts. Presented at Sudbury River Stakeholders Meeting, Boston, MA, October 06, 2009.
Abstract: Scientific presentation on WASP8 model for modeling mercury in Sudbuy River, MA.

PRESENTATION Usepa’s Ecological Exposure Modeling Science: Frameworks, Components and the Emerging Community of Practice for Reuse 10/06/2009
JOHNSTON, J. M., G. F. LANIAK, G. WHELAN, D. Ames, AND N. GABER. Usepa’s Ecological Exposure Modeling Science: Frameworks, Components and the Emerging Community of Practice for Reuse. Presented at ISEM 2009 Conference, Quebec City, QC, CANADA, October 06 - 09, 2009.
Abstract: The Ecosystem Services Research Program of the EPA Office of Research and Development envisions a comprehensive theory and practice for characterizing, quantifying and valuing ecosystem services and their relationship to human well-being. This vision of future environmental decisionmaking is planned as an innovative, online decision support platform with a full range of data exploration methods and models connecting managers and policy developers with their ecosystems of interest, from local to regional and national scales. Both systems thinking and integrated multi-disciplinary research are essential to program success. The interrelationships and interdependencies among the elements of ecosystem assessment aimed at the valuation of ecosystem services are far more complex than the straight-forward ecosystem type-service-value relationship typically used to describe such assessments. Modeling plays a central role in formalizing scientific understanding and connecting monitoring data with a variety of approaches (e.g., statistical, mathematical, Bayesian) that describe system behavior and enable the forecasting of future ecosystem states for decisionmaking. To facilitate reuse and interoperability of data, methods and models within the wider environmental modeling community (EPA and beyond), scientific information and developed products will have a shared architecture. This makes it possible for data to inform model development and verification needs and for models to facilitate data needs across scales, filling gaps and providing information that cannot be cost-effectively sampled for a national program, for all services at all areas and times of interest.

PRESENTATION Meeting in Spain: Environmental Mass Spectrometry: Emerging Contaminants and Current Issues 09/30/2009
RICHARDSON, S. D. Meeting in Spain: Environmental Mass Spectrometry: Emerging Contaminants and Current Issues. Presented at IV Scientific Meeting of the Spanish Society of Mass Spectrometry, Castellon, SPAIN, September 30 - October 02, 2009.
Abstract: Slide presentation for the Fourth Scientific Meeting of the Spanish Society of Mass Spectrometry, September 30 - October 2, 2009.

PRESENTATION Empirical Modeling of Fecal Indicator Bacteria, Enterococci and E. Coli, at South Shore Beach, Milwaukee, Wi 09/29/2009
ZEPP, R. G., M. J. CYTERSKI, E. M. WHITE, M. MOLINA, K. L. WOLFE, R. S. PARMAR, L. Olsen, S. Zhang, J. Qiu, J. Wong, J. Varner, O. Tedrow, R. Paddock, S. Mueller-Spitz, S. McLellan, AND M. Bruesch. Empirical Modeling of Fecal Indicator Bacteria, Enterococci and E. Coli, at South Shore Beach, Milwaukee, Wi. Presented at Great Lakes Beach Association Meeting, Milwaukee, WI, September 29 - October 01, 2009.
Abstract: Scientific presentation at the Great Lakes Beach Association meeting.

PRESENTATION Advanced Exposure Metrics for Chemical Risk Analysis: Systems Biology and 'omic-Based Biomarkers for Exposure Reconstruction 09/29/2009
COLLETTE, T. W., Q. TENG, D. R. EKMAN, J. M. LAZORCHAK, D. L. LATTIER, M. GOLDSMITH, M. KOSTICH, AND J. D. PLEIL. Advanced Exposure Metrics for Chemical Risk Analysis: Systems Biology and 'omic-Based Biomarkers for Exposure Reconstruction. Presented at BOSC Computational Toxicology Research Program Review, Research Triangle Park, NC, September 29 - 30, 2009.
Abstract: Direct measurement of human exposure to environmental contaminants in real time (when the exposure is actually occurring) is rare and difficult to obtain. This frustrates both exposure assessments and investigations into the linkage between chemical exposure and human disease. However, it is feasible to obtain information on the levels of environmental contaminants (and their metabolites and adducts) in the biofluids of individuals that may have been exposed. Furthermore, it is feasible to obtain information on the occurrence of specific diseases and other adverse conditions in various human demographics. The Agency’s exposure and risk assessments could be greatly improved if these chemical biomarkers could be used to both reconstruct previous exposure scenarios, and to predict the future likelihood of adverse effects. While progress has, indeed, been made along these paths, biomarker methods based solely on xenobiotics and their metabolites/adducts are inherently limited. This new research program (still in the planning stages) is based on the belief that systems biology approaches and ‘omic-based biomarkers, when used in conjunction with tradition biomarkers, offer great promise for both exposure reconstruction and for elucidating the linkages between exposures and adverse outcomes.

PRESENTATION Development of a Searchable Metabolite Database and Simulator of Xenobiotic Metabolism 09/29/2009
JONES, W. J., P. K. SCHMIEDER, R. C. KOLANCZYK, AND O. Mekenyan. Development of a Searchable Metabolite Database and Simulator of Xenobiotic Metabolism. Presented at BOSC Computational Toxicology Research Program Review, Research Triangle Park, NC, September 29 - 30, 2009.
Abstract: A computational tool (MetaPath) has been developed for storage and analysis of metabolic pathways and associated metadata. The system is capable of sophisticated text and chemical structure/substructure searching as well as rapid comparison of metabolites formed across chemicals, species, and/or experimental condition. Using this tool, a metabolism database (metabolic pathways and associated metadata) has been constructed primarily from rat metabolism in vivo studies of pesticide chemicals to allow critical analysis and interpretation of data by risk assessors, and to assist researchers in formulating and investigating hypotheses critical to the understanding of metabolic activation. The database also serves as the foundation of an expert system under development to predict metabolite formation for use by risk assessors and researchers to identify chemicals of concern.

PRESENTATION Linkage of Exposure and Effects Using Genomics, Proteomics, and Metabolomics in Small Fish Models 09/29/2009
COLLETTE, T. W., G. T. ANKLEY, D. VILLENEUVE, S. W. EDWARDS, D. H. MILLER, D. C. BENCIC, D. R. EKMAN, J. M. LAZORCHAK, R. WANG, M. BREEN, R. CONOLLY, N. Denslow, N. Garcia-Reyero, D. Martinovic, E. Perkins, E. Orlando, K. Watanabe, AND M. Sepulveda. Linkage of Exposure and Effects Using Genomics, Proteomics, and Metabolomics in Small Fish Models. Presented at BOSC Computational Toxicology Research Program Review, Research Triangle Park, NC, September 29 - 30, 2009.
Abstract: Poster for the BOSC Computational Toxicology Research Program review. Knowledge of possible toxic mechanisms/modes of action (MOA) of chemicals can provide valuable insights as to appropriate methods for assessing exposure and effects, thereby reducing uncertainties related to extrapolation across species, endpoints and chemical structure. However, MOA-based testing seldom has been used for assessing the ecological risk of chemicals. This is in part because past regulatory mandates have focused more on adverse effects of chemicals (reductions in survival, growth or reproduction) than the MOA through which these effects are caused. A recent departure from this involves endocrine-disrupting chemicals (EDCs), where there is a regulatory need for USEPA to understand both MOA and adverse outcomes. To achieve this understanding, advances in predictive approaches are required whereby mechanistic changes caused by chemicals at the molecular level can be translated into apical responses meaningful to ecological risk assessment, such as effects on development and reproduction, and ultimately population-level impacts.

PRESENTATION Emerging Environmental Contaminants: What's New 09/28/2009
RICHARDSON, S. D. Emerging Environmental Contaminants: What's New. Presented at Seminar at the University of Nancy, Nancy, FRANCE, September 28, 2009.
Abstract: Slide presentation on emerging environmental contaminants for a seminar in France.

PRESENTATION Development of An in Silico Metabolic Simulator and Searchable Metabolism Database for Chemical Risk Assessments 09/10/2009
JONES, W. J., P. K. SCHMIEDER, AND R. C. KOLANCZYK. Development of An in Silico Metabolic Simulator and Searchable Metabolism Database for Chemical Risk Assessments. Presented at Pesticide Management Regulatory Agency, Health Canada, Ottawa, ON, CANADA, September 10, 2009.
Abstract: The US EPA is faced with long lists of chemicals that need to be assessed for hazard, and a gap in evaluating chemical risk is accounting for metabolic activation resulting in increased toxicity. The goals of this project are to develop a capability to predict metabolic maps of xenobiotic chemicals and the most likely formed metabolites. Results will identify metabolites of equal or greater toxicity than the parent chemical. An existing metabolism simulator is being refined by focusing on reactions leading to increased toxicity. To achieve the goals, metabolism data collected from the peer-reviewed literature as well as from registrant-submitted data required for chemical registration/re-registration will be collected for risk assessor evaluation/use and for training and improvement of the metabolic simulator. Data will be electronically stored, accessed, and visualized using a database manager software under development. The database software is capable of text and chemical structure search functions, depiction of metabolic maps, and provides access via structures to coded metabolism information and associated metadata. The database will be used by US EPA scientists to increase efficiency of metabolism data access and performance of risk assessments. In its simplest mode, the database will furnish curated structures of chemicals/pesticides and their metabolites suitable for searches in other databases and provide metabolic maps plus tabulations of amounts of metabolites and associated metadata. In a more advanced mode, the database will allow the risk assessor to perform searches for specific compounds and toxicophores and identify metabolism commonalities and differences across pesticides and species. Metabolic simulator performance will be enhanced by collecting chemical metabolism maps from the published literature and EPA Program Office files and determined from in vitro and in vivo rat hepatic experiments. Newly acquired maps (and transformations) will be used to re-train the metabolic simulator and improve reliability estimates. Data from these studies are used to improve the metabolic simulator and prioritize chemicals for testing that have the potential to be bioactivated to more toxic species. Finally, prioritized chemical lists (based upon predicted toxic effects of parent chemical and metabolites) with transformation reliability estimates will be provided to scientists and EPA Program Offices for chemical evaluations (risk assessments) and ranking for toxicity testing. This research will expand the knowledge-base of metabolic pathways and transformation products for important groups of toxic chemicals and demonstrate an approach that integrates metabolism simulation with toxic exposure and effects modeling.

PRESENTATION Gasoline Composition and Associated Contaminant Transport 09/09/2009
WEAVER, J. W. Gasoline Composition and Associated Contaminant Transport. Presented at US EPA Region 3 LUST Technical Workshop, Shepardstown, WV, September 08 - 10, 2009.
Abstract: Slide presentation on gasoline composition and associated contaminant transport presented at the U.S. EPA Region 3 LUST Technical Workshop.

PRESENTATION A Regionalized Flow Duration Curve Method to Predict Streamflow for Ungauaged Basins: A Case Study of the Rappahannock Watershed in Virginia, USA 09/06/2009
MOHAMOUD, Y. M. AND R. S. PARMAR. A Regionalized Flow Duration Curve Method to Predict Streamflow for Ungauaged Basins: A Case Study of the Rappahannock Watershed in Virginia, USA. Presented at Joint IAHS & IAH International Convention, Hyderabad, INDIA, September 06 - 12, 2009.
Abstract: A method to predict streamflow for ungauged basins of the Mid-Atlantic Region, USA was applied to the Rappahannock watershed in Virginia, USA. The method separates streamflow time series into magnitude and time sequence components. It uses the regionalized flow duration curve (RFDC) to predict the magnitude component and uses the time sequence of a nearby gauged site to estimate the time sequence component. We evaluated the performance of the RFDC method for predictions in ungauged sites by comparing RFDC streamflow predictions from several ungauged sites with observed streamflow from nearby gauged sites. In addition, we compared RFDC streamflow predictions with streamflow simulated for the ungauged sites by the Hydrologic Simulation Program Fortran (HSPF).

PRESENTATION Changes in Markers of Genotoxicity in Relation to Exposure to Disinfection By-Products in Swimming Pools 08/25/2009
Kogevinas, M., C. Villanueva, L. Font, M. Nieuwinhuijsen, S. D. RICHARDSON, T. Grummt, J. Grimalt, AND R. Marcos. Changes in Markers of Genotoxicity in Relation to Exposure to Disinfection By-Products in Swimming Pools. Presented at ISEE 2009 Conference, Dublin, Northern Ireland, IRELAND, August 25 - 29, 2009.
Abstract: Exposure to disinfection by-products (DBPs) has been associated with cancer risk, but the mechanisms of action are poorly understood. A recent study found increased bladder cancer risk among subjects attending swimming pools, where uptake of DBPs, such as trihalomethanes (THMs) can be particularly high through dermal absorption and inhalation. We evaluated in an experimental study whether swimming in pools was associated with markers of genotoxicity. We identified increases in markers of genotoxicity associated with exposure to THMs in swimming pools. These increases were modest, and findings should be verified in larger studies.

PRESENTATION Light-Induced Transformations of the C60 Derivative, Fullerenol: Interactions With Natural Organic Matter 08/19/2009
ZEPP, R. G., L. Kong, K. Chan, AND O. Tedrow. Light-Induced Transformations of the C60 Derivative, Fullerenol: Interactions With Natural Organic Matter. Presented at 238th ACS National Meeting & Exposition, Washington, DC, August 16 - 20, 2009.
Abstract: Recent studies have indicated that fullerenes, an important class of nanomaterials, are photodegraded by solar radiation and can sensitize the photoproduction of reactive oxygen species such as singlet oxygen. Because natural organic matter (NOM) can retard photoreactions that are sensitized by buckminsterfullerene (C60), it was concluded that association of fullerenes with NOM increases the environmental persistence of this class of nanomaterials. Results from this study contradict this conclusion in part by showing that NOM (in the 2 to 4 mg C/L range) enhances the photodegradation of fullerenol, a hydrophilic, hydroxylated derivative of C60. Evidence is provided that fullerenol can be extensively mineralized under environmental conditions by a combination of direct and NOM-sensitized photolysis and post-irradiation bacterial respiration of labile photoproducts of the fullerenol. Dissolved inorganic carbon (DIC) was identified as the major photoproduct in the pH 4 to 7 range and the ratio of moles of DIC produced to moles of fullerenol reacted reached 26 or approximately 47% of complete mineralization at the end of 90 hrs of exposure to simulated solar radiation. Rose Bengal did not efficiently photosensitize the oxidation of fullerenol, indicating that singlet oxygen probably is not directly involved in the NOM-enhanced photoreactions of fullerenol.

PRESENTATION Bill Glaze: A Legend, a Teacher, and a Gentleman 08/17/2009
RICHARDSON, S. D. Bill Glaze: A Legend, a Teacher, and a Gentleman. Presented at 238th ACS National Meeting & Exposition, Washington, DC, August 16 - 20, 2009.
Abstract: Presentation for the American Chemical Society Meeting, August 2009.

PRESENTATION Analysis of Perfluorinated Chemicals and Their Fluorinated Precursors in Sludge: Method Development and Initial Results 08/16/2009
Yoo, H., J. J. ELLINGTON, J. W. WASHINGTON, T. JENKINS, AND L. LIBELO. Analysis of Perfluorinated Chemicals and Their Fluorinated Precursors in Sludge: Method Development and Initial Results. Presented at 238th ACS National Meeting & Exposition, Washington, DC, August 16 - 20, 2009.
Abstract: A rigorous method was developed to maximize the extraction efficacy for perfluorocarboxylic acids (PFCAs), perfluorosulfonates (PFSAs), fluorotelomer alcohols (FTOHs), fluorotelomer acrylates (FTAc), perfluorosulfonamides (FOSAs), and perfluorosulfonamidoethanols (FOSEs) from wastewater-treatment sludge. PFCAs and PFSAs in test sludge were analyzed by LC/MS/MS. Of five solvents tested for their PFCAs/PFSAs extraction effectiveness, 50%/50% (v/v) ACN/MeOH extraction yielded the highest concentrations. Pretreatment of sludge with NaOH and HCl, prior to extraction, recovered additional PFCAs/PFSAs (e.g., PFOA and PFOS), but KOH and K2S2O8 digestion were less effective than no pretreatment. Volatile fluorochemicals in sludge were extracted with methyl tert-butyl ether (MTBE) using GC-MS. NaOH-treated sludge resulted in recovery of more FTOHs, especially 8:2 FTOH. Presently we are investigating if this observation comes from the OH--facilitated hydrolysis of FTAc. With these efforts, we have been able to measure at least ten volatile fluorochemicals from test sludge at the concentrations of sub-ng to tens ng/g (ww). The identification of a few suspected volatile fluorochemicals, for which no standards exist, was evaluated with a derivitization technique.

PRESENTATION Determining Aqueous Fullerene Particle Size Distributions By Asymmetric Flow Field-Flow Fractionation (Af4) Without Surfactants 08/16/2009
Isaacson, C., X. MA, B. Wigington, T. Burns, AND D. BOUCHARD. Determining Aqueous Fullerene Particle Size Distributions By Asymmetric Flow Field-Flow Fractionation (Af4) Without Surfactants. Presented at 238th ACS National Meeting & Exposition, Washington, DC, August 16 - 20, 2009.
Abstract: To determine the behavior of nanoparticles in environmental systems, methods must be developed to measure nanoparticle size. Asymmetric Flow Field Flow Fractionation (AF4) is an aqueous compatible size separation technique which is able to separate particles from 1 nm to 10 µm in diameter based on differences in particle diffusion coefficients. Many AF4 size separation methods use surfactants to ensure particle stability; however, the use of such surfactants may alter particle characteristics. A surfactant-free AF4 method was developed to size fractionate aqueous C60 aggregates (aqu C60) generated by sonication in deionized water. Aqu/nC60 aggregates ranged in size from less than 100 nm to 450 nm (the filter cutoff), as determined by dynamic light scattering in flow through mode and further corroborated by batch analysis with dynamic light scattering and electron microscopy. Mass determination by LC-MS showed less than 15% of the aqu C60 had diameters less than 100 nm, while 50% of the mass of the aqu C60 had diameters between 140 and 250 nm. Additionally, the use of 1 mM NaN3 resulted in 40% of the aqu/nC60 being deposited in the AF4 channel and use of channel flow splitting increased detector response, though not to the extent expected.

PRESENTATION Kinetics, Mechanisms and Stereoselective Metabolism of 1,2,4-Triazole Fungicides and the Implications for Human Health and Ecological Risk Assessment 08/16/2009
KENNEKE, J. F., C. S. MAZUR, W. M. HENDERSON, A. W. GARRISON, S. E. Ritger, T. J. Sack, C. C. Brown, AND J. K. Avants. Kinetics, Mechanisms and Stereoselective Metabolism of 1,2,4-Triazole Fungicides and the Implications for Human Health and Ecological Risk Assessment. Presented at 238th ACS National Meeting & Exposition, Washington, DC, August 16 - 20, 2009.
Abstract: A major uncertainty in risk assessment is determining the exposure of a chemical stressor to a target organism; a confounding issue is the transformation of the chemical inside the target organism. Increasingly, physiologically based pharmacokinetic (PBPK) models are becoming the preferred tool to describe the fate of xenobiotics in physiological systems. These models can be used to evaluate target tissue dose relative to route of exposure and extrapolate results between species. One obstacle preventing full implementation of PBPK models for risk assessment is the lack of xenobiotic metabolism data for a majority of organic chemicals of concern. We have utilized specific enzyme inhibitors, human CYPs, stable isotopes, stereoselective transformations, molecular docking and in silica modeling to elucidate the mechanisms and kinetics of conazole metabolism in numerous vertebrate and invertebrate species, including humans. The entire paradigm, from delineating the kinetics and mechanisms of xenobiotic transformations to PBPK model development, has been used to improve human health and ecological risk assessment. Results will be presented that illustrate the different approaches and techniques used for studying xenobiotic transformations in biological systems and how experimental results are used to improve risk assessment while reducing the reliance upon in vivo animal tests.

PRESENTATION Computational Toxicology: A 21st Century Approach for Conducting Chemical Risk Assessments 08/13/2009
WEBER, E. J. Computational Toxicology: A 21st Century Approach for Conducting Chemical Risk Assessments. Presented at Superfund Contaminants: The Next Generation Workshop, Tucson, AZ, August 12 - 14, 2009.
Abstract: Slide presentation on computational toxicology presented at the Superfund Contaminants: The Next Generation Workshop in Tucson Arizona.

PRESENTATION Roadmap for Interdisciplinary Research on Drinking Water Disinfection By-Products 08/09/2009
RICHARDSON, S. D. Roadmap for Interdisciplinary Research on Drinking Water Disinfection By-Products. Presented at Drinking Water Disinfection By-Products Gordon Research Conference, South Hadley, MA, August 09 - 14, 2009.
Abstract: Slide presentation on interdisciplinary research on drinking water disinfection by-products which summarized important issues with drinking water disinfection by-products and focused on emerging, unregulated DBPs.

PRESENTATION Identification and Prediction of Fish Assemblages in Streams of the Albemarle-Pamlico Basin, USA 08/06/2009
CYTERSKI, M. J. Identification and Prediction of Fish Assemblages in Streams of the Albemarle-Pamlico Basin, USA. Presented at 94th Ecological Society of America Annual Meeting, Albuquerque, NM, August 02 - 07, 2009.
Abstract: Set within the Ecological Services Research Program (ESRP) of USEPA’s Office of Research and Development, a multi-disciplinary research collaborative (MEERT –Multimedia Ecological Exposure Research Team) has taken on a challenge to develop a regional assessment of several ecosystem services (primarily water quantity, water quality, and fish productivity) in the Albemarle-Pamlico Estuary System (APES), an area encompassing six major drainage basins and spanning three ecoregions (Virginia Highlands, Piedmont, Southeastern/Middle Atlantic Coastal Plain). The collaborative group has developed a modeling system that will produce not only a current accounting of particular ecosystem services in the APES, but also simulate the consequences of altered stressor scenarios (changes in nitrogen and mercury loadings, land use and global climate) on the production of these services. This poster details how we provided the ecological model (BASS) with preliminary required information, namely, the initial fish community in the stream segment to be simulated. We had 53 such stream segments (three prototype HUCs for initial methodological/framework testing, and fifty sample HUCs) for which initial fish communities needed to be defined.

PRESENTATION Methods and Tools for Evaluating Uncertainty in Ecological Models: A Survey 08/06/2009
PURUCKER, S. T., L. S. MATOTT, AND J. E. BABENDREIER. Methods and Tools for Evaluating Uncertainty in Ecological Models: A Survey. Presented at 94th Ecological Society of America Annual Meeting, Albuquerque, NM, August 02 - 07, 2009.
Abstract: Poster presented at the Ecological Society of America Meeting. Ecologists are familiar with a variety of uncertainty techniques, particularly in the intersection of maximum likelihood parameter estimation and Monte Carlo analysis techniques, as well as a recent increase in Bayesian applications. This poster reviews evaluation concepts for integrated environmental modeling and surveys relevant software-based tools, some from areas of model evaluation and uncertainty analysis rarely visited by ecologists.

PRESENTATION Regional Modeling of Ecosystem Services Provided By Stream Fishes 08/06/2009
RASHLEIGH, B., L. M. PRIETO, S. T. PURUCKER, L. A. SUAREZ, AND M. C. BARBER. Regional Modeling of Ecosystem Services Provided By Stream Fishes. Presented at 94th Ecological Society of America Annual Meeting, Albuquerque, NM, August 02 - 07, 2009.
Abstract: Fish habitat and biodiversity for fish are valuable ecosystem services provided by rivers. Future land development and climate change will likely alter these services, and an understanding of these responses can guide management and restoration priorities. We used hierarchical models that account for natural differences in ecoregion and river drainage to predict fish biodiversity and the presence of selected indicator fish species within the Albemarle-Pamlico basin, using predictors of land use, flow, temperature, and environmental setting from the USGS NHD Plus dataset. Biodiversity response to flow varied across the region, with the mountain ecoregion and the Chowan subbasin being most sensitive to flow; these regions may also be priorities for restoration. The most parsimonious models for indicator fish species typically included positive responses to either flow or velocity. Odds ratios indicated that the strongest responses to these variables occurred for darters, followed by suckers and eel. We used these models to estimate and map regional changes in these ecosystem services under IPCC-based future scenarios.

PRESENTATION Influence of Land Use on the Stable Carbon Isotopic Composition and Concentration of Dissolved Organic Carbon and Dissolved Inorganic Carbon in Georgia Piedmont Headwater Streams 07/12/2009
BURKE, R. A. Influence of Land Use on the Stable Carbon Isotopic Composition and Concentration of Dissolved Organic Carbon and Dissolved Inorganic Carbon in Georgia Piedmont Headwater Streams. Presented at Gordon Research Conference on Catchment Science: Interactions of Hydrology, Biology & Geochemistry, Andover, NH, July 12 - 17, 2009.
Abstract: Headwater streams are the dominant land-water interface across much of the landscape and provide many important ecological services. Cycling and transport of various carbon fractions, which serve as important food sources for downstream aquatic ecosystems, are among the important functions of headwater streams. Dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) are two of the most ecologically important carbon fractions. A wet chemical oxidation analyzer coupled to an isotope ratio mass spectrometer is used to measure the stable carbon isotopic composition (delta 13C) and concentrations of DOC and DIC in stream water samples collected monthly from 15 headwater streams. The study area is characterized by extensive poultry and cattle production and a rapidly growing human population, and the study catchments contain varying proportions of forest, pasture, developed, wetland, and open water land cover. Linear regression techniques are being used to develop simple models describing the influence of land cover on DOC and DIC stable isotopic compositions and concentrations. Results to date indicate that: (1) mean delta 13C-DOC and mean delta 13C-DIC in study streams range from -28.8 to -27.2 parts-per-thousand (ppt) and -18.0 to -13.0 ppt, respectively; (2) mean DOC and DIC concentrations range from 1.5 to 5.9 mg/L and from 3.0 to 8.0 mg/L, respectively; (3) watershed pasture land cover is the best descriptor of DOC concentration and delta13C-DOC; (4) DOC concentration and delta 13C-DOC are positively correlated with watershed pasture land cover; (5) watershed open water (positive correlation) and buffer open water (negative correlation) land cover together provide the best description of DIC concentration; and (6) watershed developed land cover (inverse relationship) is the best descriptor of 13C-DIC. These results suggest that organic wastes added to pastures as a result of poultry and cattle production add measureable quantities of 13C-enriched DOC to indigenous streams.

PRESENTATION Stereoselective Microbial Transformation of Triadimefon to Triadimenol in Soils: Varying Production Rates of Triadimenol Stereoisomers Could Impact Risk Assessment 07/12/2009
GARRISON, A. W., J. K. AVANTS, AND W. J. JONES. Stereoselective Microbial Transformation of Triadimefon to Triadimenol in Soils: Varying Production Rates of Triadimenol Stereoisomers Could Impact Risk Assessment. Presented at Chirality 2009, Breckenridge, CO, July 12 - 15, 2009.
Abstract: The microbial transformation of triadimefon, an agricultural fungicide of the 1,2,4-triazole class, was followed over several months under aerobic conditions in 3 different soil types to observe rates and products of transformation as well as enantiomer fractions of parent and products. The transformation was stereoselective. The primary transformation involves reduction of the prochiral ketone moiety of triadimefon to an alcohol, triadimenol, which has 2 chiral centers and 4 stereoisomers. The ratios of the 4 stereoisomers, while different from each other, were similar for each soil type. The triadimenol formed by soil transformation of triadimefon, however, showed no such stereoisomer pattern; instead, varying production rates were observed for each of the 4 triadimenol stereoisomers, resulting in all stereoisomer ratios being different from each other. This result is important in risk assessment if toxicity of the environmental transformation products were to be compared to that of the commercial triadimenol. In addition, since it is known that the stereoisomers of triadimenol differ in their toxicities, at least to fungi and rats, and that their relative abundance can vary with metabolism of the exposed species, the biological activity of the triadimenol that is formed by microbes in soils and, indeed, by any biological species, probably depends on the relative abundance of its 4 stereoisomers. This is a risk assessment issue that, in principle, applies to any chiral pesticide and its metabolite.

PRESENTATION Estimation of Diffuse Layer Model (Dlm) Intrinsic Acidity and Electrolyte Ion Site Binding Constants 06/14/2009
LOUX, N. T. Estimation of Diffuse Layer Model (Dlm) Intrinsic Acidity and Electrolyte Ion Site Binding Constants. Presented at Joint 13th IACIS International Conference on Surface and Colloid Science and 83rd American Chemical Society Colloid and Surface Science Symposium, New York, NY, June 14 - 19, 2009.
Abstract: Presentation on the estimation of diffuse layer model (DLM) intrinsic acidity and electrolyte ion site binding constants.

PRESENTATION In Pursuit of the Elusive Bound Site Activity Coefficient 06/14/2009
LOUX, N. T. In Pursuit of the Elusive Bound Site Activity Coefficient. Presented at Joint 13th IACIS International Conference on Surface and Colloid Science and 83rd American Chemical Society Colloid and Surface Science Symposium, New York, NY, June 14, 2009.
Abstract: Presentation on the pursuit of the elusive bound site activity coefficient.

PRESENTATION Iodo-Dbp Formation Form the Reaction of Chlorinated Oxidants With X-Ray Contrast Media in the Presence of Natural Organic Matter 06/08/2009
DUIRK, S. E., C. Lindell, C. C. Cornelison, T. A. Ternes, AND S. D. RICHARDSON. Iodo-Dbp Formation Form the Reaction of Chlorinated Oxidants With X-Ray Contrast Media in the Presence of Natural Organic Matter. Presented at Micropol and Ecohazard 2009 Conference, San Francisco, CA, June 08 - 10, 2009.
Abstract: Scientific meeting presentation.

PRESENTATION Meeting in San Francisco: Integrated Disinfection By-Products Mixtures Research: Results from the Four Lab Study 06/08/2009
RICHARDSON, S. D., J. E. SIMMONS, M. G. NAROTSKY, L. D. CLAXTON, E. S. HUNTER, R. J. MILTNER, J. G. PRESSMAN, T. F. SPETH, G. E. RICE, L. K. TEUSCHLER, S. W. Krasner, AND H. S. Weinberg. Meeting in San Francisco: Integrated Disinfection By-Products Mixtures Research: Results from the Four Lab Study. Presented at Micropol and Ecohazard 2009 Conference, San Francisco, CA, June 08 - 10, 2009.
Abstract: This study involves the collaboration of the four national laboratories of the U.S. Environmental Protection Agency (EPA), as well as other scientists from universities and water utilities, and is termed the ‘Four Lab Study’. The purpose of this study is to address concerns related to potential health effects from exposure to complex mixtures of drinking water disinfection by-products (DBPs) that cannot be addressed directly from toxicological studies of individual DBPs or simple DBP mixtures. Adverse health effects evaluated in this study include the reproductive and developmental effects observed in some recent human epidemiologic studies of drinking water, as well as several other toxicological endpoints. Along with extensive toxicity testing on these complex drinking water mixtures, DBPs were comprehensively identified using gas chromatography (GC) with low and high resolution electron ionization (EI) and chemical ionization (CI) mass spectrometry (MS). In addition, 75 priority DBPs were quantified, using GC/MS or GC with electron capture detection. Many DBPs were identified, including trihalomethanes (THMs), iodo-THMs, haloacetic and other halo-acids, haloamides, halonitromethanes, haloaldehydes, haloketones, halonitriles, nitrosodimethylamine (NDMA) and other nitrosamines, MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone), and MX analogues. Several DBPs, including bromochloroacetamide, bromodichloroacetamide, dibromochloroacetamide, brominated tins, and chloro-, bromo-, and iodo-phenols, have not been previously reported in the literature. Many DBPs identified were not present in either the NIST or Wiley mass spectra library databases. Toxicological endpoints investigated included reproductive and developmental effects for parental (P0), first generation (F1), and second generation (F2) rats. Toxicological effects included a slight, but significant delay in puberty for F1 female rats. Other toxicological effects included mutagenicity, which supports earlier findings of mutagenicity for chlorinated drinking water.

PRESENTATION Transport of Fullerene Nanoparticles in Saturated Porous Media 06/08/2009
BOUCHARD, D., XIN MA, C. Isaacson, AND J. W. WEAVER. Transport of Fullerene Nanoparticles in Saturated Porous Media. Presented at Micropol & Ecohazard 2009 Conference, San Francisco, CA, June 08 - 10, 2009.
Abstract: The high strength, electrical conductivity, and electron affinity of fullerenes has lead to their utilization in fuel cells and drug-delivery devices, as well as in cosmetics and other applications. Though C60 fullerene is very insoluble in water, studies have shown that C60 fullerene can form stable colloidal suspensions in water that result in C60 aqueous concentrations many orders of magnitude above C60’s aqueous solubility. These studies have raised concern over the mobility of fullerene colloids in porous media, particularly for particles less than one micron that are characteristic of fullerene suspensions. The objectives of this study were to investigate the transport of colloidal C60 aggregates formed in water without the aid of organic solvents (aqu/C60) through Iota quartz sand porous media. Pulse inputs of aqu/C60 aggregates in suspensions with different solution chemistries were introduced into the columns and column effluent was monitored over time for mass (using LC/MS), as well as particle charge and size (dynamic light scattering). Particle mass transport was simulated using a modified form of the 1-D advective-dispersive transport model with terms for particle attachment and detachment rate, as well as for a limiting particle retention capacity of the collectors. The results of the model simulations are discussed in light of the contributions of the suspension background solution chemistry and particle interception, gravitational settling, and diffusion processes on particle retention.

PRESENTATION Size Determination of Aqueous C60 By Asymmetric Flow Field-Flow Fractionation (Af4) and in-Line Dynamic Light Scattering 06/01/2009
Isaacson, C., X. MA, B. Wigington, AND D. BOUCHARD. Size Determination of Aqueous C60 By Asymmetric Flow Field-Flow Fractionation (Af4) and in-Line Dynamic Light Scattering. Presented at SETAC Europe 19th Annual Meeting, Goteborg, SWEDEN, May 31 - June 04, 2009.
Abstract: To date, studies on the environmental behaviour of aggregated aqueous fullerene nanomaterials have used the entire size distribution of fullerene aggregates and do not distinguish between different aggregate size classes. This is a direct result of the lack of analytical methods for the size separation of aggregated fullerenes. Asymmetric flow field flow fractionation (AF4) is a separation technique which is able to separate particles from 1 nm to 100 µm in diameter based on differences in particle diffusion coefficients in aqueous media. Upon size-separation using AF4, C60 aggregates ranged in size from less than 40 nm to 450 nm (the filter cut-off). The size distribution was found to be contingent on the method of aggregate generation. The aggregate sizes were determined by dynamic light scattering and corroborated with electron microscopy. AF4 fractions were also analyzed for apparent surface charge and mass concentration. As the size of the C60 aggregates increased the absolute value of their zeta potential decreased. Mass determination of AF4 fractions showed 50% of the mass of the C60 aggregates had diameters between 140 and 250 nm.

PRESENTATION Fullerene Transport in Saturated Porous Media 06/01/2009
MA, X., D. BOUCHARD, J. W. WEAVER, AND C. Isaacson. Fullerene Transport in Saturated Porous Media. Presented at SETAC Europe 19th Annual Meeting, Goteborg, SWEDEN, May 31 - June 04, 2009.
Abstract: We investigated the effects of background solution chemistry and residence time within the soil column on the transport of aqu/C60 through saturated ultrapure quartz sand columns. Aqu/C60 breakthrough curves were obtained under different pore water velocities, solution pHs, and ionic strengths. Retention profiles along the columns were also obtained. Transport of aqu/C60 through the columns was simulated using a modified form of the 1-D advective-dispersive transport model with terms for non-equilibrium particle attachment and detachment rates, as well as for a limiting particle retention capacity of the collectors. This study represents an initial step in understanding the transport of fullerene aggregates in porous media and lays the groundwork necessary for studying fullerene transport in more complex, environmentally relevant systems.

PRESENTATION Emerging Environmental Contaminants: What’s New 06/01/2009
RICHARDSON, S. D. Emerging Environmental Contaminants: What’s New. Presented at 57th ASMS Conference on Mass Spectrometry, Philadelphia, PA, May 31 - June 04, 2009.
Abstract: Much has been achieved in the way of environmental protection over the last 30 years. However, as we learn more, new concerns arise; for example, potential adverse health effects (e.g., cancer, reproductive and developmental effects, and endocrine disruption), bioaccumulation, and widespread distribution. This presentation will discuss emerging environmental contaminants that are currently of concern to the U.S. EPA and to other agencies, and will focus on the use of mass spectrometry for their measurement and identification. Mass spectrometry remains a key analytical tool both for measuring these emerging environmental contaminants at low environmental levels (often at low or sub-ng/L) and for identifying new environmental contaminants not previously known. Liquid chromatography (LC)/electrospray ionization (ESI)-mass spectrometry (MS) is used to measure polar contaminants because most of them are polar and require the use of LC/MS and LC/MS/MS. Gas chromatography (GC)/MS is also still used to measure less polar contaminants and some polar ones (using derivatization), and it continues to be an important technique for identifying new contaminants, particularly through the use of high resolution-MS. Increasingly, high resolution is also being used with LC/MS/MS, mostly through the use of time-of-flight (TOF) mass spectrometers and quadrupole-TOF mass spectrometers to distinguish between ions of the same nominal mass that can coelute in complex environmental samples.

PRESENTATION Estimation of Physical Properties and Chemical Reactivity Parameters of Organic Compounds for Environmental Modeling By Sparc 05/31/2009
HILAL, S. H. AND L. A. Carreira. Estimation of Physical Properties and Chemical Reactivity Parameters of Organic Compounds for Environmental Modeling By Sparc. Presented at SETAC Europe 19th Annual Meeting, Goteborg, SWEDEN, May 31 - June 04, 2009.
Abstract: Mathematical models for predicting the transport and fate of pollutants in the environment require reactivity parameter values that is value of the physical and chemical constants that govern reactivity. Although empirical structure activity relationships have been developed that allow estimation of some constants, such relationships are generally valid only within limited families of chemicals. The computer program, SPARC, uses computational algorithms based on fundamental chemical structure theory to estimate a large number of chemical and physical properties for a wide range of organic molecules from molecular structure. A "toolbox" of mechanistic perturbation models has been developed that can be implemented where needed for a specific reactivity query. Resonance models were developed and calibrated using measured light absorption spectra, whereas electrostatic interaction models were developed using measured pKas in water. Solvation models (i.e., dispersion, induction, H-bonding, etc.) have been developed using various measured physical properties data. At the present time, SPARC’s physical property models predict vapor pressure and heat of vaporization (as a function of temperature), boiling point (as a function of pressure), diffusion coefficient (as a function of pressure and temperature), activity coefficient, solubility, partition coefficient and GC retention time as a function of solvent and temperature. For chemical reactivity, SPARC estimates pKas in any solvent and in the gas phase, zwitterionic/hydration constants, tautomeric equilibrium, carboxylic acid ester/organophosphorus hydrolysis rate constants, E1/2 reduction potential and electron affinity. SPARC is online and can be used at http://ibmlc2.chem.uga.edu/sparc.

PRESENTATION Effects of Dna Extraction Procedures on Bacteroides Profiles in Fecal Samples from Various Animals Determined By Terminal Restriction Fragment Length Polymorphism Analysis 05/18/2009
Lee, Y. J. AND M. MOLINA. Effects of Dna Extraction Procedures on Bacteroides Profiles in Fecal Samples from Various Animals Determined By Terminal Restriction Fragment Length Polymorphism Analysis. Presented at American Society for Microbiology General Meeting, Philadelphia, PA, May 17 - 21, 2009.
Abstract: A major assumption in microbial source tracking is that some fecal bacteria are specific to a host animal, and thus provide unique microbial fingerprints that can be used to differentiate hosts. However, the DNA information obtained from a particular sample may be biased depending on the performance of the extraction procedure. In this study, we compared profiles generated by T-RFLP analysis to determine the diversity of Bacteroides communities in different animal hosts obtained by different DNA extraction procedures. A total of 29 feces from nine animals and three sludge samples from a wastewater treatment facility were collected and tested to identify unique T-RFs. DNA was extracted using five different commercial DNA purification kits, amplified with FAM-labeled general Bacteroidales marker (Bac32F) and digested with HaeIII for 16 hrs at 37°C. Fecal DNA was generally extracted more efficiently by the kits employing the bead-beating method; however, T-RFs profiles displayed more background noise. Profiles of T-RFs indicated that the diversity of fecal Bacteroides varied significantly in fecal material from the same animal source when extracted using different procedures. Therefore, the extraction procedure needs to be taken into consideration when studying the structure and composition of the microbial community as output from the different procedures may influence the perceived diversity of the sample. Bacteroides T-RFs were more abundant in fecal DNA from ruminants which were found to be distinctly different from the patterns derived from other animal fecal communities. Host specific T-RFs were identified in the fecal DNA from pig, deer, and sheep, regardless of the kit used for DNA extraction. The variability of T-RFs among feces from various animals could be used for identification of host-specific fingerprints in microbial source tracking studies.

PRESENTATION Effect of Environmental Parameters on the Qpcr Signal of Enterococci in Tropical Waters 05/18/2009
MOLINA, M., S. Hunter, E. M. WHITE, Y. J. Lee, AND R. G. ZEPP. Effect of Environmental Parameters on the Qpcr Signal of Enterococci in Tropical Waters. Presented at American Society for Microbiology General Meeting, Philadelphia, PA, May 17 - 21, 2009.
Abstract: Fecal contamination is the major source of pathogens in recreational waters. The need for quick public notifications has expanded the interest in the use of a rapid, quantitative polymerase chain reaction method (qPCR) to determine enterococci density. However, very little information is available on the fate and transport of the enterococci qPCR signal under a variety of environmental scenarios. In this study, we focused on the relationship among the enterococci qPCR signal, culturable enterococci and environmental parameters in marine tropical waters. Sampling was conducted from June thru October, 2008 at a beach located in Luquillo, Puerto Rico. Samples were collected three times per week at waist deep and processed for enterococci densities using membrane filtration and qPCR. Hydrometeorological and biogeochemical variables were collected on a 24 hour basis using automated equipment installed at the beach. The culturable enterococci information indicated that the highest densities were detected closer to a mangrove channel draining a sanitary sewer pumping station. Culturable and qPCR enterococci densities were not linearly correlated (r2= 0.05) indicating that outputs from each methodology cannot be explained by the same environmental variables. Using a statistical modeling approach, a preliminary model was developed to identify the variables that can best predict enterococci concentrations. Results indicated that the flow of the closest river was the strongest variable. This result suggests that flow may be a good surrogate for other, more proximate, sources. Data collected during this study identifies the parameters that best describe the variability of the enterococci molecular signal, providing a basis for the development of more accurate predictive models that can be used as alternative tools for fast assessments of recreational water quality.

PRESENTATION Levels of Viable Enterococci Fecal Indicator Bacteria at a Marine Subtropical Beach: Assessing Temporal and Spatial Variability 05/18/2009
Aranda, D. I., J. Capri, R. G. ZEPP, E. M. WHITE, M. MOLINA, M. Gidley, AND C. Sinigalliano. Levels of Viable Enterococci Fecal Indicator Bacteria at a Marine Subtropical Beach: Assessing Temporal and Spatial Variability. Presented at American Society for Microbiology General Meeting, Philadelphia, PA, May 17 - 21, 2009.
Abstract: Beach water quality monitoring is an important tool to inform the public of health risks from recreational beach use, as well as to assess the impacts of land-based sources of pollution on coastal ecosystems. Many beach monitoring programs in the US currently utilize a strategy of sampling a particular beach for enterococci and/or fecal coliforms at one or two sample sites once or twice on a weekly basis and inferring weekly microbial water quality from these snapshots. We report here a study conducting an intense surveillance effort to determine if a single, weekly field grab sample accurately reflects the enterococci levels observed from more extensive sampling at several beach locations. The surveillance effort was conducted for a three month period in the summer of 2008 at a popular sub/tropical marine beach in Miami, Florida. Water column sampling involved 6 different transect locations, three times a day on four distinct days each week. Enterococci were enumerated by traditional membrane filtration (EPA Method 1600) and EnteroLert. Data representing single weekly points were randomly chosen from the compiled intensive data set of averaged enterococci colony forming units. The analysis compared weekly single sampling, to that of an intense surveillance effort that indicated a high temporal and spatial variability of enterococci levels. Due to the highly variable enterococci levels in the different locations and times, we conclude that single weekly sampling is not particularly representative of enterococci levels at different beach locations during a particular week. This may provide further insight for the improvement of water quality surveillance efforts and better means of informing the public that recreate in marine subtropical beaches.

PRESENTATION Using Streamflow as a Predictor of Biotic Health in the Upper Oconee Watershed 04/27/2009
Sterling, J. AND B. RASHLEIGH. Using Streamflow as a Predictor of Biotic Health in the Upper Oconee Watershed. Presented at 2009 Georgia Water Resources Conference, Athens, GA, April 27 - 29, 2009.
Abstract: Macroinvertebrates are commonly used as biological indicators of stream habitat and water quality. Chronic reduced streamflows can have a significant impact on biota, decreasing in-stream habitat and influencing water quality. Many aquatic macroinvertebrates are sensitive to changes in water chemistry, and streams with degraded water quality are often characterized by low macroinvertebrate diversity. A previous study by the Upper Oconee Watershed Network related the Georgia Adopt-A-Stream biotic index for macroinvertebrates to water chemistry (Kominoski et al., 2007), but did not consider the effects of streamflow, which may also influence index scores. In this study, we used multiple measures of flow (including seasonal mean and variability) from USGS gage data to examine patterns in the macroinvertebrate index for seven tributaries of the North and Middle Oconee Rivers in Clarke County, Georgia. Macroinvertebrate samples were collected seasonally from 2000-2008 and scored using the Georgia Adopt-A-Stream biotic index. Statistical analyses suggest that streamflow is a significant predictor for the biotic index. The index appears to have a peaked response to streamflow and a negative response to flow variability. These results provide insight to the factors structuring benthic macroinvertebrates communities in urban streams in the Oconee River basin, and may guide the use of this index for bioassessment throughout the state of Georgia.

PRESENTATION Meeting in St. Louis: Composition and Behavior of Ethanol Gasolines 04/27/2009
WEAVER, J. W. Meeting in St. Louis: Composition and Behavior of Ethanol Gasolines. Presented at Freshwater Spills Conference, St. Louis, MO, April 27 - 30, 2009.
Abstract: Scientific presentation on the composition and behavior of ethanol gasolines.

PRESENTATION Meeting in Athens: An Assessment of Fecal Contamination in Rural Streams Impacted By Litter Applications 04/27/2009
Lee, Y. J. AND M. MOLINA. Meeting in Athens: An Assessment of Fecal Contamination in Rural Streams Impacted By Litter Applications. Presented at 2009 Georgia Water Resources Conference, Athens, GA, April 27 - 29, 2009.
Abstract: Conference presentation on assessment of fecal contamination in rural streams impacted by litter applications.

PRESENTATION Meeting in Athens, Georgia: Predictions of Biotic Health in Urban Streams With Reduced Flow 04/27/2009
Sterling, J., B. RASHLEIGH, AND A. Rosemond. Meeting in Athens, Georgia: Predictions of Biotic Health in Urban Streams With Reduced Flow. Presented at Georgia Water Resources Conference, Athens, GA, April 27 - 29, 2009.
Abstract: Conference slide presentation on predicitons of biotic health in urban streams with reduced flow.

PRESENTATION Perturbational Metabolic Profiling of Human Breast Cancer Cells 04/21/2009
TENG, Q., W. Huang, T. W. COLLETTE, AND D. R. EKMAN. Perturbational Metabolic Profiling of Human Breast Cancer Cells. Presented at ISMRM 17th Scientific Meeting & Exposition, Honolulu, HI, April 18 - 24, 2009.
Abstract: A major goal of toxicity testing is to obtain toxicity data for protecting public health and the environment from adverse effects that may be caused by exposure to environmental agents in the air, water, soil and food. The current toxicological studies that target human health effects primarily rely on animal studies. Unfortunately, large-scale animal exposure studies are expensive, requiring dedicated care and handling facilities. Furthermore, the US EPA and other organizations have adopted the goal of reducing animal usage in future toxicity testing programs. One potential approach to increase the throughput of metabolomics is to use cell cultures instead of live animals in exposure studies, which provides obvious advantages. For example, there is no need to house and sacrifice animals, costs are significantly lower, and cells can be grown and exposed rapidly. Also, human cell lines can be employed in order to avoid cross-species extrapolations. To conduct cell culture based metabolomics, we have developed a novel sample preparation method using adherent mammalian cells, which is rapid, effective, and exhibits greater metabolite retention by approximately a factor of 50 compared to the conventional sample preparation method. We have applied this approach to study the metabolic changes caused by 17α-ethynyl-estradiol (EE2) in estrogen receptor (ER)-positive MCF-7 and ER-negative MDA-MB-231 human breast cancer cell lines using NMR spectroscopy. Presented here are the details of sample preparation, NMR spectroscopy, metabolite identification, statistical analysis and intracellular metabolic changes.

PRESENTATION Predictive Modeling of a Fecal Indicator at a Subtropical Marine Beach 04/20/2009
ZEPP, R. G., E. M. WHITE, M. MOLINA, AND M. J. CYTERSKI. Predictive Modeling of a Fecal Indicator at a Subtropical Marine Beach. Presented at US EPA National Beach Conference, Huntington Beach, CA, April 20 - 22, 2009.
Abstract: The Virtual Beach Model Builder (VBMB) is a software tool that can be used to develop predictive models at beaches based on microbial data and observations (explanatory variables) that describe hydrometeorological and biogeochemical conditions. During the summer of 2008, a study was conducted to evaluate the use of VBMB in developing models for predicting enterococci concentrations at Hobie Beach, Miami FL. Water samples were collected at shin-deep and waist deep sites in the swim area (three times a day, four days a week) and the samples were processed to determine culturable enterococci and filtered for enterococci qPCR analysis and archiving. Instruments were deployed at the beach to log data that were used to develop the models. The instruments included: a weather station; an acoustic doppler current meter (ADCP); a sonde for water quality parameters; a UV radiometer system equipped with two optical sensors, each measuring UV-A and UV-B irradiance, positioned at two different depths underwater. The microbial and explanatory variables data were used by VBMB to produce multilinear regression models that optimally fit the data. Using backward elimination with Mallows Cp, VBMB was also used to develop the most parsimonious model for fitting the culturable enterococci data and also to identify the best explanatory variables from the array of potential variables available for fitting. Preliminary analysis with VMBM (using multiple linear regression without transformation of explanatory variables) identified water depth, wave height, photosynthetically active radiation, wind speed, and water temperature as the most important predictors for this beach.

PRESENTATION Urban Runoff Impact on the Qpcr Signal of Enterococci and Other Alternative Fecal Indicators in a Tropical Beach 04/20/2009
MOLINA, M., S. Hunter, E. M. WHITE, Y. L. Lee, M. J. CYTERSKI, AND R. G. ZEPP. Urban Runoff Impact on the Qpcr Signal of Enterococci and Other Alternative Fecal Indicators in a Tropical Beach. Presented at US EPA National Beach Conference, Huntington Beach, CA, April 20 - 22, 2009.
Abstract: In order to effectively control inputs of contamination to coastal recreational waters, an improved understanding of the impact of both point and non-point sources of urban runoff is needed. In this study, we focused on the effect of non-point source urban runoff on the enterococci qPCR signal in a tropical marine beach. The relationship between qPCR enterococci, presence of 16S-rRNA based markers, and biogeochemical and climatic parameters (e.g., storm events) was also investigated. Waist deep samples were collected at a beach in Luquillo, Puerto Rico from June to October, 2008. Samples, from three sites along a transect perpendicular to the shoreline, were processed for enterococci densities (EPA Method 1600) and qPCR. Automated equipment collected hydrometeorological and biogeochemical variables on a 24 hour basis. Culturable enterococci and qPCR signals peaked following the first strong rain episode. Late in the rainy season, both qPCR and culturable enterococci showed similar spatial trends with higher signals observed on the west side of the beach, which was impacted by runoff from a nearby contaminated wetland. Dissolved organic carbon concentrations were also higher on the west side, likely due to increased runoff from more frequent storm events. Data collected during this study were also used to identify relationships between different measurements of enterococci and to relate these measurements to changes observed in weather and biogeochemical properties. Culturable and qPCR densities were not linearly correlated indicating that outputs from each methodology cannot be explained by the same environmental variables. Preliminary results suggest that urban runoff influences the relationship between the qPCR signal and culturable measurements of enterococci.

PRESENTATION Optical Properties of Three Beach Waters: Implications for Predictive Modeling of Enterococci 04/20/2009
WHITE, E. M., R. G. ZEPP, M. MOLINA, AND M. J. CYTERSKI. Optical Properties of Three Beach Waters: Implications for Predictive Modeling of Enterococci. Presented at US EPA National Beach Conference, Huntington Beach, CA, April 20 - 22, 2009.
Abstract: Sunlight plays an important role in the inactivation of fecal indicator bacteria in recreational waters. Solar radiation can explain temporal trends in bacterial counts and is commonly used as an explanatory variable in predictive models. Broadband surface radiation provides a basic measure of sunlight exposure. However, the amount and quality of light that bacteria are exposed to is largely dependent on the optical properties of the water. In this study, we investigated the optical properties of waters at a temperate freshwater beach (Milwaukee, WI), sub-tropical marine beach (Miami, FL), and a tropical marine beach (Luquillo, PR), during summer 2008. UV sensors were deployed in the water column to model light attenuation as a function of depth. Surface solar (300-1100 nm) and photosynthetically active radiation (PAR, 400-700 nm), turbidity, chlorophyll, suspended sediments, dissolved organic carbon, and chromophoric dissolved organic matter were also measured and compared with respect to culturable enterococci levels. The tropical marine beach had the most intense solar irradiance and the clearest water compared to the sub-tropical marine and temperate freshwater beaches. Observed differences between beaches were complicated due to variations in extent of contamination, water temperature, salinity, and tidal influence. Bacterial counts were better correlated with UV irradiance (325 nm), compared to PAR and solar radiation, suggesting that the inclusion of more detailed light data will help improve the accuracy of predictive models.

PRESENTATION Emerging Disinfection By-Products and Other Emerging Environmental Contaminants in Water and Wastewater: What's New 04/16/2009
RICHARDSON, S. D. Emerging Disinfection By-Products and Other Emerging Environmental Contaminants in Water and Wastewater: What's New. Presented at Seminar at Loyola University, Chicago, IL, April 16, 2009.
Abstract: Slide presentation on emerging disinfection by-products in water and wastewater presented at seminar at Loyola University.

PRESENTATION Composition and Behavior of Ethanol Gasolines 03/30/2009
WEAVER, J. W., D. L. SPIDLE, AND S. Skaggs. Composition and Behavior of Ethanol Gasolines. Presented at 21st Annual National Tanks Conference and Expo, Sacramento, CA, March 30 - April 01, 2009.
Abstract: Presentation on composition and behavior of ethanol gasolines presented at the 21st Annual Tanks Conference in Sacramento, California.

PRESENTATION Gasoline Composition: Temporal Trends, Historical Lead Scavenger Data and Effects of Ethanol 03/30/2009
WEAVER, J. W., L. M. PRIETO, D. L. SPIDLE, AND S. Skaggs. Gasoline Composition: Temporal Trends, Historical Lead Scavenger Data and Effects of Ethanol. Presented at 21st Annual National Tanks Conference and Expo, Sacramento, CA, March 30 - April 01, 2009.
Abstract: Poster on gasoline composition presented at the 21st Annual National Tanks Conference.

PRESENTATION Modeling the Transport of Ethanol Fuel Blends With the Combined Hssm and Mt3d Models 03/30/2009
WEAVER, J. W., J. Zhang, M. Tonkin, AND R. J. Charbeneau. Modeling the Transport of Ethanol Fuel Blends With the Combined Hssm and Mt3d Models. Presented at 21st Annual National Tanks Conference and Expo, Sacramento, CA, March 30 - April 01, 2009.
Abstract: Poster on modeling the transport of ethanol fuel blends with the combined Hydrocarbon Spill Screening Model (HSSM) and MT3D model presented at the 21st Annual Tanks Conference.

PRESENTATION Investigation of Photochemical Properties of C60 Aggregates in Water 03/22/2009
Kong, L., K. Chan, O. Tedrow, AND R. G. ZEPP. Investigation of Photochemical Properties of C60 Aggregates in Water. Presented at 237th ACS National Meeting & Exposition, Salt Lake City, UT, March 22 - 26, 2009.
Abstract: As an emerging new material with unique structure and properties, the behavior and fate of Buckminster fullerene (C60) in natural waters has gained increasing attention. Although the water solubility of C60 is extremely low, the formation of C60 aggregates in water could alter the mobility and reactivity of C60 with variations of environmental conditions such as light, pH, ionic strength, and presence of natural organic matter. This research focused on investigating the photochemical properties of C60 aggregates in water. To be more environmentally relevant, the C60 aggregates were prepared by mixing the C60 in water without involving organic solvents (i.e. THF, etc). C60 irradiation kinetics with simulated solar and monochromatic irradiation was investigated. The direct photoreaction of C60 water suspension following the initial six days exhibited first-order kinetics with an initial quantum yield of 1.4×10-5 at an irradiation wavelength of 366 nm. No apparent change in average particle size and surface charge was observed following the irradiation. The photoreactivity of C60 aggregated in water prepared by different methods was also compared.

PRESENTATION Meeting in Turkey: Wasp Transport Modeling and Wasp Ecological Modeling 03/22/2009
AMBROSE, R. B. Meeting in Turkey: Wasp Transport Modeling and Wasp Ecological Modeling. Presented at IGEM Modeling Workshop, Istanbul, TURKEY, March 21 - 28, 2009.
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 Modeling Mercury in Streams: Wasp Development 03/17/2009
KNIGHTES, C. D. Modeling Mercury in Streams: Wasp Development. Presented at USGS/EPA Workshop on Mercury in Streams, Athens, GA, March 17 - 19, 2009.
Abstract: Slide presentation on modeling mercury in streams for the USGS/EPA Workshop.

PRESENTATION Erd Research on Nutrient and Pathogen Dynamics 03/17/2009
STEVENS, C. T. AND R. G. ZEPP. Erd Research on Nutrient and Pathogen Dynamics. Presented at EPA/USGS Mercury in Streams Ecosystems Meeting, Athens, GA, March 17 - 19, 2009.
Abstract: Slide presentation giving an overview on the ERD research on nutrient and pathogen dynamics. Focus is on characterizing the dynamics of pathogen and nutrient stressors in the environment to support water quality objectives.

PRESENTATION Grid Based Mercury Model (Gbmm): Overview, Updates, and Next Steps 03/17/2009
GOLDEN, H. E. AND C. D. KNIGHTES. Grid Based Mercury Model (Gbmm): Overview, Updates, and Next Steps. Presented at EPA/USGS Mercury in Streams Ecosystems Meeting, Athens, GA, March 17 - 19, 2009.
Abstract: Slide presentation on the Grid Based Mercury Model GBMM) presented at the EPA/USGS Mercury in Streams Ecosystems Team Meeting.

PRESENTATION Emerging Disinfection By-Products and Other Emerging Environmental Contaminants: What’s New 03/11/2009
RICHARDSON, S. D. Emerging Disinfection By-Products and Other Emerging Environmental Contaminants: What’s New. Presented at International Conference on Xenobiotics in the Urban Water Cycle, Paphos, CYPRUS, March 11 - 13, 2009.
Abstract: This presentation will cover new research and concerns regarding drinking water disinfection by-products (DBPs) and other emerging environmental contaminants, such as perfluorooctanoic acid (PFOA), pharmaceuticals, perchlorate, benzotriazoles, fuel additives (e.g., ethylene dibromide), and nanomaterials. Current developments for the 3rd Contaminant Candidate List (CCL) will also be presented, as well as the Unregulated Contaminants Monitoring Rule (UCMR). The CCL identifies environmental contaminants that the U.S. Environmental Protection Agency (EPA) is considering for regulation at a future date, and the UCMR requires drinking water utilities to monitor specific priority contaminants that the U.S. EPA is considering for regulation. Drinking water DBP issues include bladder cancer and reproductive/developmental effects that have been observed in human epidemiologic studies. It is not currently known which DBPs are responsible for those adverse health effects. To that end, research will be presented on: (1) a recently completed occurrence study of iodinated DBPs (iodo-acids and iodo-trihalomethanes), which are more toxic than regulated trihalomethanes (THMs) and haloacetic acids (HAAs); (2) ‘the Four Lab Study’, which involves the collaboration of the four national laboratories of the U.S. EPA and focuses on reproductive/developmental effects; and (3) toxicity-based identification work that focuses on the high molecular weight fraction of DBPs, for which little is known. In addition, the issues with route of exposure (ingestion, inhalation, dermal) will be presented, along with new swimming pool research, which also involves DBP exposures.

PRESENTATION Emerging Contaminants and Current Issues 03/11/2009
RICHARDSON, S. D. Emerging Contaminants and Current Issues. Presented at International Conference XENOWAC 2009, Paphos, CYPRUS, March 11 - 13, 2009.
Abstract: Keynote slide presentation on emerging contaminants and current issues including disinfection by-products.

PRESENTATION Occurrence of Lead and Lead Scavengers in Gasoline Leaked to the Subsurface 03/10/2009
SMALL, M., J. W. WEAVER, D. L. SPIDLE, AND S. Skaggs. Occurrence of Lead and Lead Scavengers in Gasoline Leaked to the Subsurface. Presented at 19th Annual AEHS Meeting & West Coast Conference on Soils, Sediments, and Water, San Diego, CA, March 09 - 12, 2009.
Abstract: Slide presentation on the occurrence of lead and lead scavengers in gasoline leaked to the subsurface for the 19th Annual AEHS Meeting and West Coast Conference on Soil, Sediment and Water.

PRESENTATION Comprehensive Identification of Chemical DBPs from Chlorinated and Brominated Swimming Pools 03/02/2009
RICHARDSON, S. D. Comprehensive Identification of Chemical DBPs from Chlorinated and Brominated Swimming Pools. Presented at Workshop on Pool Water Chemistry and Health, Dessau, GERMANY, March 02 - 03, 2009.
Abstract: Swimming pools have been recently recognized as important routes of exposure to potentially harmful chemicals. Previous epidemiologic research has shown increased incidence of asthma and other respiratory effects for people who have significant indoor swimming pool exposures, and new research has shown a significant increased risk of bladder cancer from chlorinated swimming pool exposure. Swimming pool treatment is very similar to what is used for treating drinking water: chlorine is commonly used (either as a gas, liquid bleach, or stabilized solid tablet), and it can react with natural organic matter present in the water or with human inputs (sweat, urine, skin cells, etc.) to form disinfection by-products (DBPs). Our previous research on outdoor pools revealed similar DBPs to what has been found for drinking water (e.g., trihalomethanes, haloacetic acids, and other halogenated chemicals), but to-date. In this research, we used low and high resolution gas chromatography (GC)/mass spectrometry (MS) to comprehensively identify DBPs formed in indoor chlorinated and brominated swimming pools sampled in Barcelona, Spain. Human health endpoints and mutagenicity of the water were also measured by collaborators in this study. DBPs identified included an abundance of halo-acids (including many unregulated ones), halomethanes, haloacetonitriles, haloaldehydes, haloketones, halonitromethanes, haloamides, haloalcohols, and halophenols. Many of these DBPs have not been reported previously for swimming pool waters, and many of the chemicals were not present in the mass spectral library databases (NIST or Wiley), which necessitated the use of high resolution-MS to generate potential empirical formulas and the manual interpretation of the mass spectra to identify their structures. In general, more nitrogen-containing DBPs were observed in these pool water samples than are typically found in drinking water. Bromoform levels were approximately twice as high in the pools treated with bromine vs. chlorine, but interestingly, other DBPs and their levels were similar in brominated vs. chlorinated pools, likely owing to the high levels of bromide already in the Barcelona raw source waters that feed into drinking water treatment (and serve as source waters for further swimming pool treatment).

PRESENTATION Climate Change and Water Resources: Regional Issues and Responses 02/27/2009
RASHLEIGH, B. Climate Change and Water Resources: Regional Issues and Responses. Presented at Switzer Fellows Retreat, Los Angeles, CA, February 27, 2009.
Abstract: Seminar slide presentation on climate change and water resources presented at the Switzer Fellows Retreat, February 27, 2009.

PRESENTATION Seeing the Big Picture in Freshwater Fish Ecology: Can We Connect the Dots? 02/24/2009
MCGARVEY, D. J. Seeing the Big Picture in Freshwater Fish Ecology: Can We Connect the Dots? Presented at Seminar at the Odum School of Ecology, University of Georgia, Athens, GA, February 24, 2009.
Abstract: Slide presentation for a seminar at the University of Georgia Odum School of Ecology, Athens, Georgia on freshwater fish ecology.

PRESENTATION Mercury in Our Air, Water and Food: the Global, Regional and Local Toxin 02/13/2009
KNIGHTES, C. D. Mercury in Our Air, Water and Food: the Global, Regional and Local Toxin. Presented at Nicholas School of the Environment Spring Symposium at Duke University, Durham, NC, February 14, 2009.
Abstract: Seminar slide presentation about mercury in our air, water and food.

PRESENTATION Issues in Assessing the Fate of Manufactured Nanomaterials in Porous Media 02/04/2009
LOUX, N. T. Issues in Assessing the Fate of Manufactured Nanomaterials in Porous Media. Presented at Seminar in the Department of Plant and Soil Sciences, University of Georgia, Athens, GA, February 04, 2009.
Abstract: Slide presentation for seminar at the University of Georgia on issues in assessing the fate of manufactured nanomaterials in porous media.

PRESENTATION Meeting in Missouri: the Next Generation of Disinfection By-Products 01/26/2009
RICHARDSON, S. D. Meeting in Missouri: the Next Generation of Disinfection By-Products. Presented at Seminar at the Missouri Insitute & Technology, Rolla, MO, January 26, 2009.
Abstract: Slide presentation on disinfection by-products for the Missouri Institute of Science and Technology.

PRESENTATION Predictions of Biotic Health in Urban Streams With Reduced Flow 01/24/2009
Sterling, J., B. RASHLEIGH, AND A. Rosemond. Predictions of Biotic Health in Urban Streams With Reduced Flow. Presented at Seminar at University of Georgia Undergraduate Research Symposium, Athens, GA, January 24, 2009.
Abstract: Seminar presentation on predictions of biotic health in urban streams with reduced flow.

PRESENTATION Modeling Options for Wetlands 01/15/2009
RASHLEIGH, B. Modeling Options for Wetlands. Presented at Ecosystem Services Research Program National Wetlands Meeting, Charleston, SC, January 15 - 16, 2009.
Abstract: Slide presentation on modeling options for wetlands presented in Charleston, SC, January 15-16, 2009.

PUBLISHED REPORT Wasp7 Stream Transport Model Theory and User's Guide: Supplement to Water Quality Analysis Simulation Program (Wasp) User Documentation 09/30/2009
AMBROSE, R. B. AND T. WOOL. Wasp7 Stream Transport Model Theory and User's Guide: Supplement to Water Quality Analysis Simulation Program (Wasp) User Documentation. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/100 (NTIS PB2010-104716), 2009.
Abstract: The standard WASP7 stream transport model calculates water flow through a branching stream network that may include both free-flowing and ponded segments. This supplemental user manual documents the hydraulic algorithms, including the transport and hydrogeometry equations, the model input and output, and a series of model verification tests.

PUBLISHED REPORT Development and Example Application of a Pilot Model for the Biogeochemical Cycling of Mercury in Watersheds: Serafm-Nps 09/30/2009
KNIGHTES, C. D. Development and Example Application of a Pilot Model for the Biogeochemical Cycling of Mercury in Watersheds: Serafm-Nps. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/114 (NTIS PB2010-104717), 2009.
Abstract: Mercury is a developmental neurotoxicant, ubiquitous in the environment, existing both naturally and through anthropogenic additions, resulting in human and ecological exposure risks primarily via consumption of mercury contaminated fish tissue. To better understand the risk associated with mercury exposure, it has become necessary to not only understand the mercury biogeochemical cycling within water bodies where typical mercury exposure occurs, but to also understand terrestrial mercury biogeochemical cycling, including mercury deposition, transformation, and transport to receiving water bodies. Here, we present a relatively straight-forward and transparent spreadsheet-based pilot model to simulate the biogeochemical cycling of mercury in watersheds. The watershed is divided into different land use types (currently impervious, forest, grassland, agriculture-pasture, agriculture-row crops, and wetlands) lumping all similar land use types into one box. This model uses a simple box-model approach, with mechanistic differential mass balance equations to describe the transformation and transport of speciated mercury (Hg(0), Hg(II), and MeHg) within each land use type, predicting soil mercury concentrations and transport processes (volatilization, erosion, leaching, runoff, and total flux to receiving water bodies). The model is dynamic, running on time steps of years, allowing for development of mercury concentrations over long time periods. The output of this model was designed to provide loading information to water body models such as SERAFM and WASP.

PUBLISHED REPORT Modeling the Impacts of Hydromodification on Water Quantity and Quality 09/30/2009
MOHAMOUD, Y. M., A. C. SIGLEO, AND R. S. PARMAR. Modeling the Impacts of Hydromodification on Water Quantity and Quality. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/116 (NTIS PB2010-104718), 2009.
Abstract: Hydromodification activities are driven by human population growth and resource extraction and consumption including urbanization, agriculture, forestry, mining, water withdrawal, climate change, and flow regulation by dams and impoundments. These anthropogenic activities alter natural flow regimes and lead to reduced downstream water quantity and degraded water quality. Recently, USEPA and states recognized hydromodification as a stressor and a leading source of water quality impairment in streams and rivers. Hydromodification-induced stressors include chemical pollutants, pathogens, nutrients, suspended solids, and flow and habitat alteration. The diverse and interacting nature of hydromodification-induced stressors has made Total Maximum Daily Load (TMDL) development for impaired streams and rivers a major regulatory challenge. Because hydromodification integrates stressors that have combined, cumulative, and synergistic effects on water quantity and quality, TMDL modeling approaches are not well-suited for simulating the impacts of hydromodification. Modeling integrated stressors requires the development and application of predictive models and innovative modeling approaches, such as the Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) modeling framework. Although BASINS has been in use for the past 10 years, there has been limited modeling guidance on its applications for complex environmental problems, such as modeling impacts of hydromodification on water quantity and quality. This report consists of two parts: Part 1 presents the development of a BASINS-based methodology that is applicable to modeling hydromodification. Part 2 is a case study of how the proposed modeling approach can forecast the impacts of urbanization on water quantity and quality.

PUBLISHED REPORT Composition and Behavior of Fuel Ethanol 04/21/2009
WEAVER, J. W., S. A. Skaggs, D. L. SPIDLE, AND G. C. Stone. Composition and Behavior of Fuel Ethanol. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/037 (NTIS PB2009-115367), 2009.
Abstract: Ethanol usage in the United States has increased due in part to the elimination of methyl tert-butyl ether from the fuel supply and to the mandates of Congress. Two samples, one each from a wet mill and a dry mill ethanol plant, were obtained before denaturing. Each of these samples contained mostly ethanol, but also low concentrations of water, methanol, and higher molecular weight alcohols (up to five carbons). The wet mill sample also contained ethyl acetate and an ether, 1,1-diethoxyethane. The allowable denaturants for fuel ethanol are similar to gasoline. Since the denaturants are immiscible with water, the ability of the denatured fuel ethanol to absorb water is limited. Experiments with E95 and E85 showed that these both began to phase separate when about 15% water was added to the E95 or E85. The gasoline was released gradually as water was added to the fuel. For E95, there is a smaller amount of gasoline in the fuel (2% to 5%) so less gasoline can be released. The changes in volume when water and ethanol or water and E85 are mixed displayed a deficit of 3% at maximum. The byproducts of fuel ethanol production are less soluble, sorb more, diffuse less readily, and are less volatile than ethanol. It’s likely, however, that the increased ethanol concentration in water will increase the solubility of the byproducts, as it does the petroleum hydrocarbons The production byproducts compose less than 1% of the mass of the fuel. Releases of fuel ethanol will be dominated by the ethanol.

SUMMARY Meert Nanomaterial Ecological Process Modeling 03/30/2009
LOUX, N. T. Meert Nanomaterial Ecological Process Modeling. U.S. Environmental Protection Agency, Washington, DC, EPA/600/S-09/023, 2009.
Abstract: The 2001 U.S. National Nanomaterial Initiative was established in order to coordinate U.S. nanotechnology research and development. Although the U.S. Environmental Protection Agency (U.S. EPA) Office of Research and Development (ORD) participated in the initial effort, the U.S. EPA ORD National Exposure Research Laboratory (NERL) established a nanomaterial research program in 2005. Subsequently, based on previous core NERL-Athens research, the NERL-Athens Multimedia Ecological Exposure Research Team (MEERT) incorporated a Nanomaterial Ecological Process Model effort into the overall MEERT program. MEERT is designed to develop multimedia tools useful for assessing ecological conditions and stressors. However, as noted by the EPA Science Advisory Board, multimedia modeling tools should be “living” programs that are upgraded concurrently with advances in the fields of scientific and technical research. Specifically, the MEERT Nano program represents a “futures” component of the overall MEERT program.

 

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