United States Environmental Protection Agency Office of Research and Development Washington DC 20460 EPA/600/R-93/079 June 1993 Environmental Research Laboratory - Athens, GA 1992 Highlights Status Quo Scenario increase in Soil Carbon 1990 to 2030 Key (gC/mA2) 500 tO < 750 750 to < 1000 1000 to < 1250 1250 to < 1500 1500 to < 1750 1750 to < 2000 >= 2000 Athens Environmental Research Laboratory, Assessment Branch ------- Cover Illustration: Computer modeling and Geographical Information Systems support investigations of agriculture's capacity to serve as a sink or a source for greenhouse gases. One study from the Lab's Global Change Research Program indicates that carbon is accumulating in the agricultural soils of the central United States. The carbon that accumulates in these sot Is was recently atmospheric carbon dioxide, a greenhouse gas. ------- The U.S. Environmental Protection Agency's Environmental Research Laboratory at Athens, Georgia, conducts and manages basic and applied research to predict, assess, and reduce human and environmental exposures and risks from pollutants in freshwater, marine, and terrestrial ecosystems and the emission of greenhouse gases to the atmo- sphere. Athens researchers identifiy and characterize the natural biological and chemical pro- cesses in soils, surface waters, and sediments that affect the environmental fate of toxic substances, such as solvents, pesticides, or metals. The results are applied in state-of-the- art multimedia transport models for predicting and assessing exposures and managing environmental pollution problems. A second emphasis involves the development of ecological risk assessment methods to evaluate pollutant and other stressor on ecosystems such as the Great Lakes, Chesapeake Bay, and large agricultural areas. Lab-developed fate and process data and assessment techniques support EPA's environ- mental management, regulation, and enforcement activities. Major research areas include global climate change, stratospheric ozone depletion, ecological risk assessment, sedi- ment quality evaluation, computational chemistry, identification of complex organic pollutants, nonpoint source pollution management, agroecosystem monitoring and assessment program, multimedia nitrogen impacts, bioremediation, chemical remediation, and wellhead protection. The Center for Exposure Assessment Modeling distributes models and documentation to environmental managers throughout the world by mail and via electronic bulletin board. RosemarieC. Russo, Ph.D., Director Robert C. Ryans, Technical Information Manager Environmental Research Laboratory Office of Research and Development U.S. Environmental Protection Agency 960 College Station Road Athens GA 30605-2720 The Office of Research and Development (ORD) conducts in integrated program of scientific research and development on the sources, transport and fate processes, monitoring, control, and the assessment of risk and effects of environmental pollutants. These activities are implemented through its headquarters, offices, technical support offices, and twelve research laboratories distributed across the country. The research focuses on key scientific and technical issues to generate knowledge supporting sound decisions today, and to antici- pate the complex challenges of tomorrow. With a strong and forward-looking research program, less expensive, more effective solutions can be pursued and irreversible damage to the environment can be prevented. Printed on Recycled Paper ------- ------- Atomic Force Microscopy Laboratory chemists are applying the new technology of atomic force microscopy in studies of the processes of oxidation, reduc- tion, precipitation, and dissolution of metal ions. Atomic force microscopy provides scientists, for the first time, with the capability to analyze the structure, morphology, and chemical reactivity of environmental surfaces at the atomic level of resolution. It is these environmental surfaces—mineral, organic and microbial in nature—that play a large role in controlling the fate of organic and inorganic pollutants in the environment. Initial work involves confirming surface structures of silicates and humic and fulvic acids, including observation of features important to metal binding processes. Results of these examinations of environmental processes by atomic force microscopy will permit the development of improved models for predicting the behavior of pollutants in water and soil environments. [G. Bailey, 706-546-3307] New Method for Detecting Azo Dyes Research to characterize the structures of sulfonated azo dyes resulted in the discovery of a potential means of identifying these com- pounds in complex structures in ambient environments. The discovery was made through the application of secondary ion mass spectrometry/tandem mass spectrometry. These dyes comprise more than half of the 57 million pounds of textile dyes used annually in the United States. Because laboratory studies have shown that these dyes and their aromatic amine metabolites, resulting from microbial transformation in ambient environments, cause cancer in laboratory test animals, it is impor- tant to be able to identify and measure the dyes in aqueous and solid wastes. Although the study was designed to elucidate structures of the dyes, an important by-product was the detection of many fragment ions. Selective ionization, therefore, shows promise as a means of identifying and measuring azo dyes and other chemicals in the complex mixtures in which they are normally found in ambient environments. [S. Richardson, 706-546-3199] Biosystems Technology Development A major focus of EPA's Biosystems Technol- ogy Development Program has been the investigation of bioremediation technologies for the in situ treatment of hazardous waste. On-going research by Athens scientists and others was presented at a meeting in May. Research results will provide the basis for establishing effective in situ bioremediation strategies for treatment of single and mixed- chemical wastes often encountered in waste sites and for developing scientifically sound strategies for treatment at Superfund sites. The May forum included discussions of research projects on bioremediation of soils and sediments contaminated with aromatic amines; characterization of microorganisms, microbial consortia, and microbial processes associated with reductive dechlorination; decontamination of PGB-contaminated sediments; and effects of metals on the anaerobic dechlorination of halogenated phenols. [J. Rogers, 706-546-3592] Predicting Organics Fate with Infrared PRC's A new approach that applies infrared-spectros- copy-based property reactivity coefficients was developed for predicting the environmental fate of organic chemicals. The potential for the new system, which is based on Fourier transforms of infrared spectra, for predicting hydrolysis rate constants for broad structural classes has been demonstrated with 41 car- boxylic acid esters exhibiting a wide range of structures and reactivities. Methods for predicting the physical and chemical constants, such as hydrolysis rates, ------- required for exposure assessm.cn.tas, arc important to the Agency as it evaluates the thousands of chemicals for which exposure and risk assessments arc required. Laboratory measurements for these chemicals are prohibi- tively slow and expensive to perform. IT. Collette, 706-546-3525] EPA's Earth Systems Modeling Program The Athens Laboratory, in cooperation with the National Center for Atmospheric Research and the Lawrence Livermore National Labora- tory, is implementing a new research program on earth systems modeling as part of the Global Climate Change Research Program. The goal is the systematic development of an earth systems model that is modular in design, enables the exploitation and further develop- ment of terrestrial biosphcric modeling components and tropospheric chemistry relationships, and produces models and modeling experiments that demonstrate the feasibility of fully coupled, three-dimensional models of earth systems. Major elements of the earth systems model framework will include atmospheric and ocean circulation and biogcochemistry models, cryosphcric models, and biophysical represen- tations of the terrestrial system including the hydrologic cycle. [L. Mulkey, 706-546-3129] SAFARI Study of Greenhouse Gas Flux Three ERL-Athcns chemists studied the effects of savanna burning on soil fluxes of trace carbon gases (carbon dioxide, methane, and carbon monoxide) as part of the Southern African Fire-Atmosphere Research Initiative (SAFARI) in September. Scientists from 12 nations participated in the month-long project sponsored by the International Geosphcre- Biosphcre Program in Kruger National Park, South Africa. SAFARI involved a wide range of activities, including analysis of satellite-generated data, collection of air emissions using aircraft, and determination of effects of biomass burning on soil fluxes of greenhouse gases. The ERL- Athens studies were conducted in collaboration with National Aeronautics and Space Adminis- tration scientists and with a team of terrestrial ecologists from public and private environmen- tal organizations in South Africa. Preliminary analyses of results indicate that both added moisture and fire greatly enhance biogenic emissions of carbon dioxide and nitric oxide from the soils, that a methane sink is not active in any of the soils before or after burning or up to 2 weeks after addition of water, and that no nitrous oxide emissions occurred. Post- SAFARI studies will involve the determination of polycyclic aromatic hydrocarbons and graphitic carbon in burned biomass residue collected from the soil surface. The PAH data will be useful in studies of fire effects. These studies will be conducted in collaboration with scientists at the Max Planck Instut fur Chemie in Mainz, Germany. [R. Zepp, 706-546-3428] Comprehensive Exposure Assessment for Agrichemicals The Lab launched a comprehensive exposure assessment modeling study on the effects of agricultural chemicals in surface water and groundwater systems and on adjacent terres- trial riparian zones. The project is part of EPA's Midwest Agrichemical Surface/Subsur- face Transport and Effects Research (MAS- TER) Program that combines EPA and U.S. Department of Agriculture research require- ments in conducting watershed-scale response analyses involving complex hydrogeological features. The Walnut Creek Watershed near Ames, Iowa, is the study site. The modeling study uses several comprehensive watershed-scale tools for the chemical exposure and aquatic habitat assessment. HSPF models surface runoff, erosion and stream, channel effects. 3DFEMWATER/3DLEWASTE simulates groundwater response. PRZM-2 integrates the field-scale effects. The models will evaluate the effects of agricultural production and agrichemicals on the ecological and geomor- phological status of the watershed. The results of these evaluations will be used in the MASTER program to develop procedures for assessing pollutant and land management effects on the midwestern cornbelt and other large areas and for designing an ecologically ------- benign management strategy that will be implemented and demonstrated on the Walnut Greek site over the next 5 years. [R. Swank, 706-546-3128] Support for EPA's Corrective Action Rule In response to a request by EPA's Office of Solid Waste (OSW) for assistance in imple- menting a Regulatory Impact Analysis (RIA), three ORD labs assembled a team of experts to provide information on ground water, surface water, and atmospheric modeling. The ORD team produced an organic and inorganic chemical database, developed specific recom- mendations for modeling in complex hydrogeological conditions, carried out com- plex case study analyses, tested and modified the computer model used in the RIA, and performed an uncertainty analysis. The experts were from the ERL-Athens, the R.S. Kerr Environmental Research Laboratory- Ada, and the Atmospheric Research and Exposure Assessment Laboratory. The RIA provides a national-scale estimate of the costs and benefits (that is, reduction in human and ecological risks) that would result in the implementation of OSW's proposed Corrective Action Rule. The integrated multimedia modeling approach developed in this effort is being applied to other important Agency issues, such as the fate of lead in the environment and cross-media risk trading. [D. Brown, 706-546-3546] EMAP Agroecosystem Study in North Carolina The quality of irrigation water supplied by farm ponds and on-farm wells is being assessed in a pilot study in North Carolina. Under EPA's Environmental Monitoring and Assess- ment Program (EMAP), samples are analyzed for atrazine, carbofuran, aldicarb, and other selected pesticides (applied to crops such as tobacco, peanuts, corn, and cotton) and nitrates. In addition, monitoring wells are installed in the Little Coharie Watershed in a statistically random pattern. These wells will provide controlled, reliable ground water data on pesticides and nitrate that can be compared with data from existing on-farm wells. The research effort also will provide an opportunity to test groundwater threat models for predic- tive capability on a variety of scales. [C. Smith, 706-546-3175] Chemical Characterization of Hazardous Waste Components Lab scientists are developing chemical trans- formation pathway profiles for more than 200 chemicals under consideration in establishing the Office of Solid Waste's Hazardous Waste Identification Rule and determining whether specific waste components are most appropri- ately modeled using the finite- or infinite- source modeling methodologies. Profiles include determination of the processes by which each chemical will degrade or be transported, sediment-water distribution coefficients, and transformation rates for the listed chemicals (parent) and their transforma- tion products (daughter) as well. After analysis of theoretical considerations, which identify likely daughter products on the basis of chemical structure, the transformation rates and equilibrium constants are arrived at by considering measured values from the literature, applying computational chemistry methods, postulating values from chemical structure, and making laboratory measure- ments for parameters considered critical to the Rule's application for chemicals for which remaining levels of uncertainty are unaccept- able. Development of these profiles is possible only because of the knowledge gained in ERL- Athens' unique 20-year program in environ- mental chemical process research. [W. Donaldson, 706-546-3183] Environmental Education Reaches Students, Teachers The Lab's Environmental Science Education Program, established in 1991 and managed by Ms. Kate McDaniel, continued its outreach activities. Twenty teachers representing school districts from across Georgia attended an intensive, 8-day workshop entitled "Envi- ------- ronmcntal Chemistry As It Relates to the Community," cosponsored with the Northeast Georgia Section of the American Chemical Society. The teachers learned innovative skills for enhancing their high school science courses. Ms. McDaniel participated as a volunteer instructor in the Presidential Class- room for Young Americans, a week-long session for high school juniors and seniors in Washington DC. The Lab was awarded a grant for environmental education through the Agency's Minority Cooperative Education Program. The grant will be used to support a Master's Candidate in Environmental Risk Management and to participate in a National Community Outreach Program. Lab staff continued their mentoring activities with students at the 4th Street Elementary School in Athens, our Partner in Education. [K. McDaniel, 706-546-3524] Achievement Awards to Azarraga, Barnwell Dr. Leo Azarraga and Mr. Thomas Barnwell received EPA Science Achievement Awards for 1992. Recipients are selected by a panel chaired by EPA's Scientific and Technical Careers Advisory Committee and including professional society representatives to recog- nize Agency scientists for outstanding contri- butions in specific technical fields. Each award is established in conjunction with a professional society. Dr. Azarraga's award, in the field of chemistry, is granted "for innovative development and application of laser spectroscopy and the Competitive Equilibrium Gaussian Distribu- tion Model to the quantitative understanding of toxic metal speciation in environmental and biological systems." Mr. Barnwcll's award, in the field of water quality, is provided "for insightful leadership in applying state-of-the-art modeling and computing concepts to meet high priority Agency water quality modeling needs." Lab Papers Win Sci-Tech Awards A journal article by Dr. Craig Barber, Dr. Luis Suarez, and Dr. Ray Lassiter claimed top honors in this year's presentation of the EPA Office of Research and Development's Scientific and Technological Achievement Awards. The Level I award, one of only two presented, went to "Modelling Bioaccumulation of Organic Pollutants in Fish with an Application to PCBs in Lake Ontario Salmonids." EPA's Science Advisory Board also awarded Level III honors to two Lab articles. The articles were "Ester Hydrolysis Rate Constants Prediction from Infrared Interferograms" by Dr. Timothy Collette and "Regiospecific Dechlorination of Pentachlorophenol by Dichlorophenol-Adapted Microorganisms in Freshwater, Anaerobic Sediment Slurries" by Dr. John Rogers (EPA coauthor). In the overall process for recognizing outstand- ing research by EPA employees, the Science Advisory Board granted 29 awards from the 114 scientific articles nominated by 16 EPA Labs and Offices. Rogers Heads Bioremediation Committee Dr. John Rogers was named Chair of the Scientific Steering Committee (Matrix Man- ager) for the Office of Research and Development's Bioremediation Research Program. The committee recommends resource allocations and directs the bioremediation programs that support Supcrfund and hazardous waste cleanup activities. McCutcheon Named Journal Editor The American Society of Civil Engineers selected Dr. Steve McCutcheon for a 2-year voluntary appointment as editor of the Journal of Environmental Engineering. In this honorary position, he will provide editorials and editor's notes bearing on the needs of the environmen- tal engineering profession. ------- Russo Serves on NAS Committee Dr. Rosemarie Russo serves on the National Academy of Science's Advisory Committee on Russia and the Newly Independent States. The Committee provides advice to the leadership of the Academy on scientific and technological issues related to the former Soviet Union and advises on most appropriate activities for the NAS in support of U.S. interests. Richardson Takes AWWA Post Dr. Susan Richardson was appointed to a research committee of the American Water Works Association. The committee reviews research proposals and provides continuing oversight of research in progress. ACS Recognizes Zepp The American Chemical Society's Division of Environmental Chemistry selected Dr. Richard Zepp to receive its Distinguished Service Award for 1992. The award recognizes Dr. Zepp's activities on the Environmental Chemistry Executive Committee. Barnwell Named to ASCE Council Mr. Thomas Barnwell accepted appointment to the Executive Committee of the American Society of Civil Engineers' Technical Council on Computer Practices. Russo Given Polish Medal The Institute of Meteorology and Water Management in Warsaw, Poland, presented its Gabriel Narutowicz Medal to Dr. Rosemarie Russo. The medal was awarded for Distin- guished Service to Environmental Science and Engineering. Loux on Journal Editorial Board The Editorial Board of Science and Technol- ogy Letters, Middlesex, United Kingdom, selected Dr. Nicholas Loux for a 1-year, voluntary, honorary appointment as an Ameri- can Editor for Chemical Speciation and Bioavailability. Burns Named to Risk Assessment Forum EPA's Risk Assessment Council named Dr. Lawrence Burns to its Risk Assessment Forum. The 13-member Forum promotes Agency- wide consensus on risk assessment issues and assures that this consensus is incorporated into appropriate risk assessment guidance. Zepp, Burke Get Innovative Research Funding A research proposal by Dr. Richard Zepp and Dr. Roger Burke was selected for award under the Office of Research and Development's Innovative Research Program. The 1-year project will develop an improved understand- ing of the role of fire in climate-biosphere interactions through the examination of polycyclic aromatic hydrocarbon content in selected environmental samples that have served as natural archives of past fire events. The research will be conducted in collabora- tion with experts at the U.S. Forest Service and Duke University. Lewis Is Sigma Xi Secretary Dr. David Lewis, Research Microbiologist at the Athens Lab, was elected Secretary of the University of Georgia Chapter of Sigma Xi, the National Scientific Research Society. ------- New Soil Scientist Dr. Dcrmont Bouchard, Research Soil Scien- tist, joined the Lab staff in August and as- sumed direction of the Center for Exposure Assessment Modeling. An EPA employee since 1985, Dr. Bouchard came to the Lab from a research liaison assignment between EPA and the USDA Agricultural Research Service in Bcltsvillc MD. Prior to that he was ORD's Regional Scientist at EPA Region 7. He began his EPA career at the R.S. Kerr Environmental Research Laboratory-Ada OK. He has a Doctorate in Agronomy from the University of Arkansas. New Analytical Chemist Ms. Dalizza Colon, who holds a Master's Degree in Analytical Chemistry from the University of Puerto Rico, joined the staff in August. Her current research examines the binding of atrazinc and its degradation prod- ucts to natural organic matter. Science and Management Fellow Ms. Ida Rosario-Hcbcr, an Environmental Science and Management Fellow, Class of 1993, under the National Urban Fellow's Program, joined the staff for a year-long residency. As a Special Assistant to the Laboratory Director, she participates in the Lab's environmental education program and is conducting an Environmental Education Assessment Survey for Educators. New NRC Associates Two scientists joined the staff under the National Research Council Associates Pro- gram. Dr. William Miller's research examines photochemical carbon transformation in natural systems as part of the Lab's Global Change Research Program. Dr. Matthew Tarr is performing fundamental studies of photo- chemical transformations of pollutants on plant surfaces. DOE Research Visitor Ms. Louise Criscenti of the Department of Energy/Battelle Northwest Laboratory joined the Lab on a year-long Interagency Agree- ment. She is assessing the use of subsurface geochemical and reactive solute transport models in regulatory decision-making at Superfund and hazardous waste sites, and testing the applicability of new models in interpreting field and laboratory data. International Research Visitors Eight scientists from six countries visited the Laboratory for periods of 2 to 12 months to carry out joint research with staff experts. The visitors represented the National Institute for Public Health and Environmental Protection, Bilthoven, The Netherlands; the State Key Laboratory of Environmental Aquatic Chemis- try, Chinese Academy of Sciences, Beijing, PRC; Institute of Meteorology and Water Management, Warsaw, Poland; Central Pollution Control Board, New Delhi, India; CIBA-Geigy Corporation, Basel, Switzerland; and the University of Catalonia, Barcelona, Spain. The Lab hosted brief (day-long) visits of scientists from Japan, Germany, The Netherlands, Brazil, Venezuela, South Africa, and the Czech and Slovak Federal Republic. Chemist Begins Research in Germany Dr. Wayne Garrison, Chemistry Branch Chief, began an 11-month joint investigation of the environmental fate of pollutants at the Insti- tute for Ecological Chemistry of the GSF Research Center for the Environment and Health, Munich, Germany. ------- Ananyeva, N.D., N.N. Naumova, J.E. Rogers, and W.G. Steen. 1992. Microbial Transformation of Selected Organic Chemicals in Natural Aquatic Systems. In: Fate of Pesticides and Chemicals in the Environment. Q.L. Schnoor (ed.). New York, John Wiley & Sons, Inc. p. 275-294. Barnwell, T.O., R.B. Jackson, E.T. Elliott, E.A. Paul, K. Paustian, A. Donigian, A. Patwardhan, A. Rowell, and K. Weinrich. 1992. An Approach to Assessment of Management Impacts on Agricultural Soil Carbon. Water, Air, and Soil Pollution. 64(l/2):423-435. Baughman, G.L., E.J. Weber, R.L. Adams, and M.S. Brewer. 1992. Fate of Colored Smoke Dyes. U.S. Department of the Army, Fort Detrick MD. Burke, R.A., T.R. Barber, and W.M. Sackett. 1992. Seasonal Variations of Stable Hydrogen and Carbon Isotope Ratios of Methane in Subtropical Freshwater Sediments. Global Geochemi- cal Cycles. 6(2): 125-138. Cavanaugh, J.E., H.S. Weinberg, A. Gold, R. Sangalah, W. Marbury, W. Glaze, T.W. Collette, S.D. Richardson, and A.D. Thruston, Jr. 1992. Ozonation Byproducts: Identification of Bromohydrins from the Ozonation of Natural Waters with Enhanced Bromide Levels. Environmental Science and Technology. 11(7):981-991. Cubillo, F., B. Rodriguez, andT.O. Barnwell. 1992. A System for Control of River Water Quality of the Community of Madrid Using QUAL2E. Water Science and Technology. 26(7-8):1867- 1873. Donaldson, W.T. 1992. The Role of Property-Reactivity Relationships in Meeting EPA's Needs for Environmental Fate Constants. Environmental Toxicology and Chemistry. 11(7):887-891. Donigian, A.S. and L.A. Mulkey. 1992. STREAM: an Exposure Assessment Methodology for Agricultural Pesticide Runoff. In: Fate ofPesticides and Chemicals in the Environment. J.L. Schnoor (ed.). New York, John Wiley & Sons. p. 297-330. Haggblom, M.M., J. Kazumi, M.D. Rivera, L.Y. Young, and J.E. Rogers. 1992. Anaerobic Transfor- mation and Degradation of Chlorobenzoates and Chlorophenols Under Four Reducing Conditions. In: Bioremediation of Hazardous Wastes (Abstracts from 5th Symposium on U.S. EPA's Biosystems Technology Development Program). U.S. Environmental Protection Agency, Washington DC. Publication No. EPA/600/R-92/126. p. 107-108. Hamrick, K.J., H.P. Kollig, and B.A. Bartell. 1992. Computerized Extrapolation of Hydrolysis Rate Data. Journal of Chemical Information and Computer Sciences. 32(5):511-514. Hicks, D.B., J.B. McConnell, L.E. Asmussen, R.A. Leonard, and C.N. Smith. 1992. Movement and Fate of Agricultural Chemicals in the Surface and Subsurface Environments Near Plains, Southwestern Georgia—Integrated Network Plan. U.S. Geological Survey, Doraville GA. Hou, M. and G.L. Baughman. 1992. Predicting the Precipitation of Acid and Direct Dyes in Natural Waters. Dyes and Pigments. 18(l):35-46. Jackson, R.B. 1992. On Estimating Agriculture's Net Contribution to Atmospheric Carbon. Water, Air, and Soil Pollution. 64(1/2):121-137. Jensen, P. I. Aagaard, R.A. Burke, P.R. Dando, N.O. Jorgensen, A. Kuijpers, T. Laier, S.C.M. O'Hara, and R. Schmaljohann. 1992. "Bubbling Reefs" in the Kattegat: Submarine Landscapes of Carbonate-Cemented Rocks Support a Diverse Ecosystem at Methane Seeps. Marine Ecology Progress Series. 83(7):103-112. Jones, W.J. and I.C. Kong. 1992. Effects of Metals on the Reductive Dechlorination of Chlorophenols. In: Bioremediation of Hazardous Wastes (Abstracts of 5th Symposium on U.S. EPA's Biosystems Technology Development Program). U.S. Environmental Protection Agency, Washington DC. Publication No. EPA/600/R-92/126. p. 55-56. ------- Lckcvicius, B., D. Sabaliunas, A. Knabikas, and J. Jankauskas. 1992. Ames Mutagenicity Tests of Three Acetanilide Herbicides During Their Alkaline Degradation. International Journal of Analytical Chemistry. 46(1-3): 141-147. Lewis, D.L., A.P. Simons, W.B. Moore, and D.K. Gattic. 1992. Treating Soil Solution Samplers to Prevent Microbial Removal of Analytes. Applied Environmental Microbiology. 58(l):l-5. Mullen, M.D., D.G. Wolf, T.J. Bcveridge, and G.W. Bailey. 1992. Sorption of Heavy Metals by the Soil Fungi Aspcrgillus niger and Mucorrouxii. Soil Biology and Biochemistry. 24(2):129-135. Parrish, R.S., C.N. Smith, and F.K. Fong. 1992. Tests of the Pesticide Root Zone Model and the Aggregate Model for Transport and Transformation of Aldicarb, Metolachlor, and Bromide. Journal of Environmental Quality. 21(4):685-697. Pcijncnbcrg, W.G.J.M., M.J. t'Hart, H.A. den Hollander, D. van de Meent, H. H. Verbloom, and N.L. Wolfe. 1992. Reductive Transformations of Halogenated Aromatic Hydrocarbons in Anaerobic Sediment-Water Systems: Kinetics, Mechanisms, and Products. Environmental Toxicology and Chemistry. 11(3):289-300. Pcijncnbcrg, W.G.J.M., M.J. t'Hart, H.A. den Hollander, D. van de Meent, H.H. Verbloom, and N.L. Wolfe. 1992. QSARs for Predicting Reductive Transformation Rate Constants of Haloge- nated Aromatic Hydrocarbons in Anoxic Sediment Systems. Environmental Toxicology and Chemistry. 11(3):301-314. Plis, Y.I. 1992. An Approach to Calculating Wind-Driven Currents and Transport of Substances in Unstratified Water Bodies Using Curvilinear Coordinates. Water Resources Research. 28(l):83-88. . Richardson, S.D., J.M. McGuire, A.D. Thruston, Jr., and G.L. Baughman. 1992. Structural Characterization of Sulfonated Azo Dyes Using Liquid Secondary Ion Mass Spectrometry/ Tandem Mass Spectrometry. Organic Mass Spectrometry. 27(3):289-299. Risscr, J. A. and G.W. Bailey. 1992. Spcctroscopic Study of Surface Redox Reactions with Manganese Oxides. Soil Science Society of America Jouranl 56(l):82-88. Rogers, J.E., W.J. Jones, E.J. Weber, and R.L. Adams. 1992. Proposed PCB Biodegradation Study at the Sheboygan River Confined Treatment Facility. In: Bioremediation of Hazardous Wastes (Abstracts fromSth Symposiumon U.S. EPA's BiosystemsTechnology Development Program). U.S. Environmental Protection Agency, Washington DC. Publication No. EPA/ 600/R-92/126. p. 51-52. Rogers, J.E., W.J. Jones, D.D. Hale, and W. Howard. 1992. Characterization of Microorganisms, Microbial Consortia, and Microbial Processes for the Reductive Dechlorination of Hazardous Wastes. In: Bioremediation of Hazardous Wastes (Abstracts from 5th Symposium on U.S. EPA's Biosystems Technology Development Program). U.S. Environmental Protection Agency, Washington DC. Publication No. EPA/600/R-92/126. p. 53-54. Schanz, R.W. and A. Salhotra. 1992. Evaluation of the Rackwitz-Fiessler Uncertainty Analysis Mcthodfor Environmental Fate andTransportModels. Water Resources Research. 24(4):1071- 1079. Tsirkunov, V.V., A.M. Nikanorov, M.M. Laznik, ^nd D-W. Zhu. 1992. Analysis of Long-term and Seasonal River Water Quality Changes in Latvia. Water Research. 26(9):1203-1216. Van Hoof, P.L. and J.E. Rogers. 1992. Influence of Low Levels of Nonionic Surfactants on the Anaerobic Dechlorination of Hexachlorobenzene. In: Bioremediation of Hazardous Wastes (Abstracts of 5th Symposium on U.S. EPA's Biosystems Technology DevelopmentProgram). U.S. Environmental Protection Agency, Washington DC. Publication No. EPA/600/R-92/ 126. p. 105-106. ------- Y^ang, P-F. and ] .L.. Martin. 1992. Temperature and Conductivity Modeling for the Buffalo River. Journal of Great Lakes Research. 17(4):495-503. Weber, E.J., J.E. Rogers, D.L. Spidle, and K.A. Thorn. 1992. Bioremediation of Soils and Sediments Contaminated with Aromatic Amines. In: Bioremediation of Hazardous Wastes (Abstracts of 5th Symposium on U.S. EPA's Biosystems Technology Development Program). U.S. Environmental Protection Agency, Washington DC. Publication No. EPA/600/R-92/126. p. 97-98. Wolfe, N.L. 1992. Abiotic Transformations of Pesticides in Natural Waters and Sediments. In: Fate of Pesticides and Chemicals in the Environment. J.L. Schnoor (ed.). New York, John Wiley &Sons. p. 93-104. Wolfe, N.L. and D.L. Macalady. 1992. New Perspectives in Aquatic Redox Chemistry: Abiotic Transformations of Pollutants in Groundwater and Sediments. Journal of Contaminant Hydrobiology. 9(1/2): 17-34. Wubah, D.A., WJ. Jones, and J.E. Rogers. 1992. Decontamination of PCB-Contaminated Sediments Through the Use of Bioremediation Technologies. In: Bioremediation of Hazardous Wastes (Abstracts from 5th Symposium on U.S. EPA's Biosystems Technology Development Program). U.S. Environmental Protection Agency, Washington DC. PublicaitonNo. EPA/ 600/R-92/126. p. 95-96. Yeh, G.T., S. Sharp-Hansen, B. Lester, R. Strobl, and J. Scarbrough. 1992. 3DFEMWATER/ 3DLEWASTE: Numerical Codes for Delineating Wellhead Protection Areas in Agricultural Regions Based on Assimilative Capacity Criterion. U.S. Environmental Protection Agency, Athens GA. Publicaiton No. EPA/600/R-92/223. Yu, Y.S. and G.W. Bailey. 1992. Reduction of Nitrobenzene by Four Sulfide Minerals: Kinetics, Products, and Solubility. Journal of Environmental Quality. 21(l):86-94. Zepp, R.G. B.C. Faust, and J. Hoigne. 1992. Hydroxy Radical Formation in Aqueous Reactions (pH 3-8) of Iron(II) with Hydrogen Peroxide: The Photo-Fenton Reaction. Environmental Science and Technology. 26(2):313-319. Zepp, R.G. 1992. Sunlight-induced Oxidation and Reduction of Organic Xenobiotics in Water. In: Fate of Pesticides and Chemicals in the Environment. J.L. Schnoor (ed.). New York, John Wiley & Sons. p. 127-140. •tr U.S. Government Printing Office: 1993 - 750-002 (60196) ------- ------- |