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W082: Reducing the Potential for Environmental Contamination by Pesticides and Other Organic Chemicals

Annual/Termination Reports (SAES-422): [02/07/2002] [05/29/2003] [04/30/2004] [02/14/2005]

Date of Annual Report: 02/07/2002

Report Information:
  • Annual Meeting Dates: 01/09/02 to 01/10/02
  • Period the Report Covers: 01/2001 to 12/2001

    • Participants:
    Brief Summary of Minutes of Annual Meeting:
    Members of W-82 produced results of practical utility in diverse areas ranging from removing petroleum contaminants from soil and groundwater to assessing off-site transport of herbicides and fumigants in the atmosphere. Work completed under Objectives 1 and 2 were used directly to improve management practices and stewardship of our natural resources (Objective 3). The results of studies conducted by researchers involved in W-82 are used by agency personnel, growers, and educators. The research often is conducted by students and postdoctoral fellows who become the research and development workforce of the future. Chair for the 2003 meeting: Sharon Clay, South Dakota State. Secretary for 2003 meeting: Mark Radosevich, Delaware

    Accomplishments:
    The members of W-82 represent a nationally and internationally recognized group of scientists whose combined efforts have made significant advancements in society?s understanding of the relationships among the distribution, transport, and persistence of chemicals. This information is essential in risk assessment, which is accepted as the scientific basis for judging the safety of chemical technology.

    Research accomplishments have centered on (1) expanding fundamental knowledge of the processes by which pesticides and other toxic organics interact in soil-water-air systems, (2) coupling and integrating these processes into useful predictive models describing the fate of chemicals in the environment, and (3) assessing various agronomic and management practices for either preventing pollution or improving remediation strategies.

    Objective 1. Characterize and quantify the basic chemical and biological processes controlling the behavior of pesticides, other organic chemical, and microorganisms in soil, water and air.

    This objective includes studies on the fate and transport of organic contaminants in soil, water, and air. Specific areas of progress for 2001 are summarized below:

    Bioavailability of Soil-sorbed Atrazine (Auburn University)

    Atrazine Degradation on Manganese Oxides (University of California - Berkely)

    Redox Properties of Humic Acids for Development of Abiotic and Biological Pathways for Herbicide Remediation (University of California - Berkely)

    Bioremediation of MTBE (University of California-Davis).

    Impact of Methyl Bromide and 1,3-dichloropropene on Soil Microbial Communities (USDA-ARS, Salinity Lab, Riverside, CA).

    Degradation of Soil Fumigants as affected by Initial Concentration and Temperature (USDA-ARS, Salinity Lab, Riverside, CA).

    Evaluation of Propargyl Bromide for Control of Barnyardgrass and Fusarium oxysporum in Three Soils. (USDA-ARS, Salinity Lab, Riverside, CA).

    Microcosm Enrichment of 1,3-dichlorpropene-degrading Soil Microbial Communities in a Compost-amended Soil. (USDA-ARS, Salinity Lab, Riverside, CA).

    Environmental Conditions Influence on Permeability of Plastic Films to Fumigant Vapors (USDA-ARS, Salinity Lab, Riverside, CA).

    Transformation of Propargyl Bromide in Soil (USDA-ARS, Salinity Lab, Riverside, CA).

    Role of Pi-Pi Interactions Between Organic Compounds and Humic Substances (Connecticut Agricultural Experiment Station, New Haven).

    Influence of Sorbate Structure on Nonideal Sorption Behavior of Organic Chemicals in Soil Organic Matter (Connecticut Agricultural Experiment Station, New Haven).

    Microbial Community Response to Repeated s-Triazine Exposure and Nutrient Availability: Linking Community Structure and Pesticide Degradation Capacity (University of Delaware). Phenanthrene Degradation In Soils Co-inoculated with Phenanthrene-degrading and Biosurfactant-producing bacteria. (University of Delaware).

    Bacteriophage Diversity and Transduction Potential in Agricultural Soils. (University of Delaware).

    Occurrence, Distribution, and Fate of Nonylphenol Polyethoxylates and 4-Nonylphenol in Northeast Kansas Wastewater Treatment Plants (Kansas State University)

    Uptake of Ethylene Dibromide (EDB) by Cranberry (Vaccinium macrocarpon) Plants (Kansas State University)

    Sorption of Acidic Pesticides on Variable-Charge Soils (Purdue University)

    Sorption of Polycyclic Aromatic Hydrocarbons (PAHs) (Purdue University)

    Fate of Benomyl Degradation Products in Soil (Purdue University)

    Fate of Animal Pharmacueticals and E. coli from Swine Manure (Purdue University)

    Phytoremediation of Contaminated Soil (Purdue University)

    Microbial Functional and Phylogenetic Diversity in Contaminated Sites (Purdue University)

    Atrazine Reactions with Clay Mineral Surfaces in the Presence of Nonionic Surfactants (Iowa State University)

    Confined Chemistry of Monovalent/Divalent Cations in Smectitic Alluvial Soils (Iowa State University)

    Monovalent Cation Confinement by Smectites and Critical Salt Dispersion Thresholds (Iowa State University)

    Ammonium-calcium Exchange in the Absence and Presence of Potassium on Vermiculite and Hydroxy-Al Vermiculite (Iowa State University)

    Surface Chemistry and Function of Microbial Biofilms (Iowa State University)

    Sorption-desorption of ?Aged? Sulfonylaminocarbonyltriazolinone Herbicides and Metabolites in Soil (USDA-ARS, St. Paul, MN)

    Sorption of Two New Sulfonylaminocarbonyltriazolinone Herbicides and Their Metabolites on Organic and Inorganic Exchanged Smectites (USDA-ARS, St. Paul, MN)

    A Novel Psba1 Gene from a Naturally-occurring Atrazine-resistant Cyanobacterial Isolate (University of Minnesota)

    Complete Nucleotide Sequence and Organization of the Atrazine Catabolic Plasmid Padp-1 from Pseudomonos Sp. Strain ADP (University of Minnesota)

    Melamine Deaminase and Atrazine Chlorohydrolase: 98% Identical but Functionally Different. (University of Minnesota)

    Microbial Degradation of s-Triazine Herbicides (University of Minnesota)

    Physical and Chemical Properties and Interactions on Interfacial Non-soil Surfaces ? Molecular and Chemical Mechanisms (USDA-ARS, Beltsville, MD)

    Characterize the Distribution, Dissipation, and Efficacy of Pesticides on Wind-erodible Sediments Using Field and Laboratory Studies (South Dakota State University)

    Objective 2. Integrate chemical and biological process information for use in models applicable across different spatial and temporal scales.

    W-82 project participants used models in various stages of research reported under objective 1 and 3. Specific areas of 2001 progress in which modeling played a prominent role are summarized below:

    Sorption Kinetics of Organic Compounds in Soil Organic Matter. Development and Application of Polymer-based Diffusion Model. (Connecticut Agricultural Experiment Station, New Haven).

    Sorption Kinetics of Organic Compounds in Soil Organic Matter. Concentration Dependence of Normalized Rates (Connecticut Agricultural Experiment Station, New Haven).

    Simulation of Contaminant Transport in Macroporous Media Using Dual-permeability Approach for Flow, Depth Variant Sorption and Domains Specific Degradation (University of Hawaii)

    Simulation of Contaminant Transport from Surface Water to Wells located on Riverbanks During Flood Periods (University of Hawaii)

    Spatial Variability of Atrazine and Alachlor Efficacy and Mineralization in an Eastern South Dakota Field (South Dakota State University)

    Predicting Pesticide Volatilization from Soils (USDA-ARS, Salinity Lab, Riverside, CA). Modeling Transport of Volatile Organic Chemicals in Unsaturated Layered Systems (USDA-ARS, Salinity Lab, Riverside, CA).

    Objective 3. Provide stakeholders with tools for developing strategies to ensure sustainable agriculture and to protect natural resource systems.

    Development of management practices which greatly reduce off-site transport of and worker exposure to fumigants including application of amendments and virtually impermeable film to the soil surface. (USDA-ARS Salinity Laboratory, California)

    Assessment of the Vulnerability of Farmstead and Rural Domestic Wells to Agrichemical Contamination (University of Hawaii)

    Post-audit Study of Ethylenedibromide (EDB) and Dibromochloropropane (DBCP) Transport in the Pearl Harbor Aquifer System (University of Hawaii)

    Chemical Leaching and Evaluation of Risk System (University of Hawaii)

    Demonstration of Bromacil Leaching Under Reduced Application Rates (University of Hawaii)

    Monitoring of Pesticide Impaired Lakes in Texas and the Use of Buffer Strips to Limit Contamination (Texas A&M)

    Impact Statements:
    Last Modified: unknown

    Date of Annual Report: 05/29/2003

    Report Information:
  • Annual Meeting Dates: 01/09/03 to 01/10/03
  • Period the Report Covers: 01/2002 to 12/2002

    • Participants:
    Brief Summary of Minutes of Annual Meeting:
    Members of W-82 conducted research addressing a diverse collection of biotic and abiotic processes that govern the fate and impact of organic pollutants including pesticides in soils, sediments and aquatic ecosystems. The results of this research have had significant practical impacts and have been used by agency personnel, regulators, legislators, growers, and educators. Work completed under Objectives 1 and 2 were used directly to improve management practices and stewardship of our natural resources (Objective 3). A further and significant benefit of this work includes the training and professional development of post-doctoral research associates, graduate and undergraduate students who will become the research and development workforce of the future.

    The meeting was called to order at approximately 8 am on 9 Jan. with a welcome and introductory comments by Sharon Clay. A substitute secretary was selected to keep minutes as Mark Radosevich was unable to attend the meeting. At 8:15, Ray Knighton provided the group with updates and developments in CSREES followed by an administrative report by Lee Sommers. The W-82 website currently served through the USDA Salinity Lab in Riverside California will be moved to Western Regional Server and administered by Dr. Sheng at University of Arkansas. The Chair for the 2004 meeting will be Mark Radosevich, Uni. of Tennessee and the Secretary for 2004 meeting will be Mike Thompson, Iowa State University. The next meeting will be hosted by Sharon Papiernik, USDA Salinity Lab, Riverside, CA. A meeting to rewrite the new proposal for the next project period will be held at Connecticut Agricultural Experiment Station, New Haven, CT on Oct. 15, 2004. Clinton Williams of the USDA Water Conservation Lab in Phoenix, AZ presented an overview of his research and was subsequently voted as the newest member of W-82.

    Accomplishments:
    The members of W-82 represent a group of scientists with broad expertise in environmental chemistry, physics, biology, soil, atmospheric, and aquatic sciences whose combined efforts have made significant advancements toward understanding of the relationships between the distribution, transport, and persistence of organic chemicals in natural environments. These scientific studies are specifically directed towards predicting the potential exposure to hazardous chemicals; an essential part of the risk assessment equation. Other benefits of the research involve the development of more efficient and cost effective methods for reclaiming or remediation of contaminated soil, sediments, and ground water and minimizing chemical inputs to the atmosphere.

    Research has focused on (1) expanding fundamental knowledge of the processes by which pesticides and other toxic organics interact in soil-water-air systems, (2) coupling and integrating these processes into useful predictive models describing the fate of chemicals in the environment, and (3) assessing various agronomic and management practices for either preventing pollution or improving remediation strategies.

    W-82 produced results of practical utility ranging from optimizing bioactive zones for most efficient in situ bioremediation of soil and groundwater to minimizing worker exposure and off-site transport of fumigants to the atmosphere. Work completed under Objectives 1 and 2 were used directly to improve management practices and stewardship of our natural resources (Objective 3). State and federal agency personnel, growers, educators, extension personnel, and private consultants used the results generated by W-82 members to protect natural resources and implement sustainable management practices. Performance of the various research projects under the W-82 umbrella resulted in the training of numerous undergraduate and graduate students, as well as many post-doctoral fellows who will further advance our understanding pollutant behavior in the environment.

    Objective 1: Characterize and quantify the basic chemical and biological processes controlling the behavior of pesticides, other organic chemical, and microorganisms in soil, water and air.
    This objective included studies on the fate and transport of organic contaminants in soil, water, and air. Most efforts by W-82 members focused on this objective and included studies on the biodegradation/metabolism of pesticides and other organic pollutants, biostimulation of indigenous microbial communities for bioremediation of perchlorate and gas oxygenates such as MTBE, as well as other organic compounds. Considerable effort by W-82 members was also devoted to elucidate sorption mechanisms of pesticides and other aromatic compounds to improve predictive fate models, and selective abiotic and biotic transformations of chiral pollutants. Studies were also conducted to characterize the degradation, distribution, and emission of volatile pesticides and other organic compounds and to evaluate various methods to prevent emissions of these ozone-destructive compounds to the atmosphere. Specific projects addressing

    Objective 1 that were active during 2002 are listed below in alphabetical order by state:
    An integrated biological and physical/chemical approach to investigate the formation and behavior of bioactive zones for prediction and enhancement of efficient in situ bioremediation  University of Arizona

    Determine the adsorptive properties of ashes arising from the burning of crop residues and bioavailability of ash-adsorbed pesticides to plants and microbes  University of Arkansas

    Identify mechanisms and products of atrazine degradation by manganese oxides - UC Berkeley

    Analysis of soil microbial communities associated with perchlorate biodegradation  UC Davis

    Bioremediation of MTBE  UC Davis

    Accelerated Degradation of Methyl Isothiocyanate in Soil. - USDA-ARS, George E. Brown Jr. Salinity Laboratory, Riverside, CA 

    Effect of Propargyl Bromide and 1,3-Dichloropropene on Microbial Communities in an Organically Amended Soil. - USDA-ARS, George E. Brown Jr. Salinity Laboratory, Riverside, CA

    Accelerated Degradation of Methyl Iodide by Agrochemicals. - USDA-ARS, George E. Brown Jr. Salinity Laboratory, Riverside, CA

    Formation and Extraction of Fumigant Residues in Soils. - USDA-ARS, George E. Brown Jr. Salinity Laboratory, Riverside, CA

    Decontamination of Chloroacetanilide Herbicides. - UC-Riverside

    Selective Transformation of Chiral Compounds. - UC-Riverside

    N2, CO2, and 1,2-dichloroethane as molecular probes of soil microstructure. - UC-Riverside

    Concentration-Dependent Kinetics of Pollutant Desorption from Soils. - Connecticut Agricultural Experiment Station

    Application of the Dual-Mode Model for Predicting Competitive Sorption Equilibria and Rates of Polycyclic Aromatic Hydrocarbons in Estuarine Sediment Suspensions.2 - Connecticut Agricultural Experiment Station

    Demonstration of the "Conditioning Effect" in Soil Organic Matter in Support of a Pore Deformation Mechanism for Sorption Hysteresis.3 - Connecticut Agricultural Experiment Station

    Studies Of p-p Interactions Between Aromatic Compounds And Aromatic Functional Groups On Humic Substances. - Connecticut Agricultural Experiment Station

    Microbial Community Responses to Atrazine Exposure and Nutrient Availability: Linking Degradation Capacity to Community Structure - University of Delaware and the Delaware Agricultural Experiment Station

    Characterization of novel biochemical pathway for naphthalene metabolism by Rhodococcus opacus M213  University of Florida

    Emissions and dispersion of 1,3-dichloropropene in Florida sandy soil in microplots affected by soil moisture, organic matter, and plastic film - University of Florida

    Sorption of Acidic Pesticides on Variable-Charge Soils - Purdue University

    Sorption of Polycylic Aromatic Hydrocarbons (PAHs). - Purdue University

    Fate of Benomyl Degradation Products in Soil - Purdue University

    Fate of Animal Pharmaceuticals and Hormones. - Purdue University

    The Influence of surfactants used in commercial herbicide formulations on the sorption and fate of atrazine. - Iowa State University

    31P NMR is used to investigate the environmental component(s) of organic and inorganic, soluble and insoluble, forms of phosphorous (P) responsible for contaminating surface and ground waters. USDA-ARS, Beltsville

    Bioavailability assessment of soil-sorbed atrazine.  Michigan State University

    Arthrobacter aurescens TC1 Metabolizes Diverse s-Triazine Ring Compounds - University of Minnesota

    Atrazine Chlorohydrolase from Pseudomonas sp. Strain ADP is a Metalloenzyme
    Enzymatic degradation of chlorodiamino-s-triazine - University of Minnesota

    Purification, substrate range, and metal center of AtzC: the N-isopropylammelide aminohydrolase involved in bacterial atrazine metabolism. - University of Minnesota

    A Novel Psba1 Gene From A Naturally-Occurring Atrazine-Resistant Cyanobacterial Isolate. - University of Minnesota

    Biodegradation of atrazine and related s-triazine compounds: from enzymes to field studies  A Review - University of Minnesota

    Metsulfuron Methyl Sorption-Desorption In Field-Moist Soils - USDA-ARS, Minnesota

    Sorption-desorption of isoxaflutole and diketonitrile degradate in soil and organoclays - USDA-ARS, Minnesota

    Br-, 14NO3-, and 15NO3- movement and sorption to soil - South Dakota State University

    Sorption/desorption of atrazine in Texas lake sediments

    Objective 2: Integrate chemical and biological process information (from objective 1) for use in models applicable across difference spatial and temporal scales.

    Studies addressing this objective developed and validated fate and transport models for volatile pesticides, contaminant transport from surface waters to wells, contaminant transport in ground water aquifers, pathogens in soils, and vulnerability of domestic wells to agricultural contamination. Specific projects addressing this objective are listed below.

    Predicting Pesticide Volatilization from Soils. - USDA-Agricultural Research Service, George E. Brown Jr. Salinity Laboratory

    Simulation of contaminant transport in macroporous media using dual-permeability approach for flow, depth variant sorption and domains specific degradation.  University of Hawaii

    Simulation of contaminant transport from surface water to wells located on riverbanks during flood periods - University of Hawaii

    Post-audit study of ethylenedibromide (EDB) and dibromochloropronane (DBCP) transport in the Pearl Harbor Aquifer System - University of Hawaii

    Transport of pathogens and selected pharmaceutical compounds in Hawaiian Oxisols.  University of Hawaii

    Assessment of the vulnerability of farmstead and rural domestic wells to agrichemical contamination - University of Hawaii


    Objective 3: Provide stakeholders with tools for developing strategies to ensure sustainable agriculture and to protect natural resource systems.

    Studies addressing this objective are specifically designed to provide end-users with user-friendly resources and management tools to ensure an environmentally sustainable agriculture, and for remediation/reclamation of impacted sites. Projects in this category addressed a range of topics from drip-irrigation applied fumigants, remediation of fumigant-contaminated soils with thiosulfate, and development of chemical risk assessment models. Specific projects are listed below.

    Assessing Emissions of Fumigants Applied via Drip Irrigation. - USDA-Agricultural Research Service, George E. Brown Jr. Salinity Laboratory

    Remediation of Fumigant Compounds in the Root Zone by Subsurface Application of Ammonium Thiosulfate. USDA-Agricultural Research Service, George E. Brown Jr. Salinity Laboratory

    Pesticide Runoff from Nursery Sites and Mitigation.  UC Riverside

    In-situ flushing techniques for the remediation of aquifers contaminated with non-aqueous phase liquids  University of Florida

    Chemical Leaching and Evaluation of Risk System (CLERS) - University of Hawaii

    Impact Statements:
    1. Elevated levels of phosphorous from over-fertilized soils have been correlated to Pfisteria outbreaks toxic to fish and possibly people in the Chesapeake Bay. 31P NMR was used to correctly ascertain chemical forms of P, and environmental kinetics of P inputs from agricultural processes to Chesapeake Bay. This knowledge can be used to minimize nutrient inputs to the Bay and reduce the potential for eutrophication and toxic algal blooms that adversely impact aquatic life and possibly humans.
    2. Pesticide bioavailability has been determined to improve risk management associated with pesticide use in agriculture and to maintain the quality of our soils and waters. This knowledge is also needed to gain perspective on the concept of environmentally acceptable endpoints which may be used as justification to consider altering the regulations regarding acceptable levels of synthetic chemicals in soils.
    3. Vadose zone and saturated zone transport models were used to simulate and validate the transport of land-applied chemicals to drinking water and to assess potential for contamination of farmstead and rural domestic wells from agricultural chemicals. Results aided in the assessment of the quality of drinking water where mandatory testing of water quality was not mandated by law. In addition, the validated models will serve as tools to predict contamination in other sensitive settings.
    4. We are working directly with stakeholders at nursery sites to assess pesticide runoff and develop management tools for meeting water quality requirements and complying with such regulations as TMDLs. Our clientele include commercial nurseries in southern California, the Regional Water Quality Control Boards, State regulatory agencies, and county/city water quality managers. The research results may be used for setting water quality standards and implementation of pesticide TMDLs.
    5. Studies have shown that biostimulation of native organisms has promise as a technology for cleaning up MTBE and perchlorate in groundwater and surface soils. Quantitative molecular genetic methods can link densities of specific microbial populations involved in biodegradation to rates of bioremediation, environmental factors, and management practices. Such techniques will be useful in evaluating the impacts of different bioremediation methods on the actual catalysts of these technologies.
    Last Modified: unknown

    Date of Annual Report: 04/30/2004

    Report Information:
  • Annual Meeting Dates: 01/15/04 to 01/16/04
  • Period the Report Covers: 01/2003 to 12/2003

    • Participants:
    Brief Summary of Minutes of Annual Meeting:
    The 2004 W-82 meeting was held January 15-16, 2004, at the George E. Brown Jr. Salinity Laboratory, 450 West Big Springs Road, Riverside, California. The meeting was hosted by the Salinity Laboratory under the leadership of Sharon Papiernik, USDA-ARS, Morris Minnesota. Thirteen scientists and the group‘‘‘‘s administrative adviser, Lee Sommers, attended the meeting. The meeting was called to order with introductory comments by Chair Mark Radosevich, University of Tennessee. The meeting included presentations of research reports by all participants as well as a business meeting. Lee Sommers presented an administrative update concerning national trends in funding for agricultural and environmental research. The participants accepted letters of resignation from Charles Helling and Allan Felsot. The chair for the next W-82 meeting will be Michael Thompson, Iowa State Univ., and it will be hosted by Joe Pignatello at the Connecticut Agricultural Experiment Station in New Haven, CT, October 14-16, 2004. A major goal of that meeting will be to write a new proposal for the next project period. At the Riverside meeting, Lee Sommers presented a time line for preparation, review, and approval of a new project, as well as advice on how to target the new proposal.

    Accomplishments:
    OBJECTIVE 1: Characterize and quantify the basic chemical and biological processes controlling the behavior of pesticides, other organic chemicals, and microorganisms in soil, water, and air.

    SOUTH DAKOTA STATE UNIVERSITY, Sharon Clay. (1) Sorption of tylosin to soil, sand, and swine manure. Tylosin fed to animals appears not to be metabolized or sorbed and is excreted in the same form as it is fed. There is a possibility of off-site movement of the chemical since runoff from soil was high, although this was not expected since sorption to soils similar to those used in the runoff study was quite high. (2) Comparison of atrazine and alachlor sorption, mineralization, and degradation potential in surface soils and aquifer sediments. Atrazine was not degraded in aquifer sample extracts, indicating long residence times for this herbicide once leached to the aquifer. Alachlor was degraded, but the major degradate, ESA, did not form in aquifer samples. This appears to indicate that ESA is leaching from the soil profile.

    ARS-USDA GEORGE E. BROWN SALINITY LABORATORY, RIVERSIDE, CA, S. Yates and S. Papiernik, . Studies included: (1) Organic Matter Effects on Phase Partitioning of 1,3-Dichloropropene in Soil; (2) Effect of Formulation on the Behavior of 1,3-Dichloropropene in Soil; (3) Competitive Degradation between the Fumigants Chloropicrin and 1,3-Dichloropropene in Unamended and Amended Soils; (4) Remediation of Methyl Iodide in Aqueous Solution and Soils Amended with Thiourea (5) Effects of Environmental Factors on 1,3-Dichloropropene Hydrolysis in Water and Soil; (6) Leaching Potential of Persistent Soil Fumigant Residues. Our work has indicated that several approaches, including application of fumigants with water, use of virtually impermeable surface tarps, application deep in soil, and construction of a highly reactive zone at the soil surface, can be effective in reducing atmospheric emissions of fumigants. We have also developed methodology to allow prediction of pathogen control prior to soil fumigation, in which a model is used to describe the fate and distribution of fumigant in soil, emissions into the atmosphere, and survival and destruction of common soil pathogens. These results will be useful in optimizing the fumigation process to minimize air contamination while maintaining uniform pest control.

    IOWA STATE UNIVERSITY, Michael Thompson. Studies included: (1) Sampling handling and atrazine sorption by soils and reference clay; (2) Sorption of atrazine and surfactant by reference clay. Sorption of emulsified atrazine by soil materials and clays was considerably different from that of neat atrazine.

    ARS-USDA, ST. PAUL, MN, W. Koskinen. Studies included: (1) Interactions of acidic herbicides bentazon and dicamba with organoclays; (2) Sorption of aged dicamba residues in soil. The objective of this work was to determine the sorption mechanism of the herbicides bentazon and dicamba on different organically modified clays. Hydrogen bonding between these herbicides and the monosubstituted amino group in octadecylammonium-exchanged organoclays reinforced the strength of the hydrophobic interactions, resulting in irreversibility of the sorption process. These results suggest that organoclays can be used to remove this type of pollutant from water or soils.

    UNIVERSITY OF ARIZONA, Raina M. Maier and Mark L. Brusseau. Studies included: (1) Saturated flow experiments using the lux reporter-fiber optic detection system; (2) Physical/chemical impacts on saturated flow transport under abiotic conditions.

    CONNECTICUT AGRICULTURAL EXPERIMENT STATION, NEW HAVEN, CT, Joe Pignatello, Yuefeng Lu, Don Zhu, and Michael Sander. Studies included: (1) History-Dependent Sorption Behavior; (2) pi ? pi Electron Donor-Acceptor Interactions Between Aromatic Compounds and Conjugated Functional Groups on Soil Organic Matter. This study has presented the first evidence that pi-pi interactions are likely mechanisms in the sorption of aromatic compounds by soil organic matter

    PURDUE UNIVERSITY, L.S. Lee, R.F. Turco, M. Bischoff, S. Sassman, S. Rao. Studies included: (1) Fate of Animal Hormones; (2) Fate of Pharmaceuticals; (3) Bioavailability of Sorbed Organic Chemicals; (4) Sorption of Polycylic Aromatic Hydrocarbons (PAHs); (5) Sorption of Acidic Pesticides on Variable-Charge Soils; (6) Fate of Benomyl Degradation Products in Soil. Antibiotics used in animal production are excreted in the urine and feces, which are commonly applied to agricultural fields after an incubation period in a manure pond. Several of these antibiotics, e.g., chlortetracycline and oxytetracycline, have been found to be quite persistent in soil and manure systems. Our studies on tetracylcines, tylosin, and carbadox show that these compounds are highly sorbed to soils, thus their most likely entry into water bodies will be through spills, surface runoff, erosion, preferential flow, and facilitated transport.

    UNIVERSITY OF TENNESSEE, Mark Radosevich. Studies included: (1) Atrazine biodegradation in soils, wetland sediments, and water; (2) Environmental fate of formaldehyde during decomposition of land applied engineered wood products.
    Biological degradation is the primary dissipation pathway for most pesticides in the soil environment. For atrazine, biodegradation pathways are more diverse than that represented by current culture collections. These communities exhibit a clear adaptive response to atrazine exposure in relation to atrazine degradation rates.

    ARS-USDA ENVIRONMENTAL QUALITY LABORATORY, BELTSVILLE, MD. Hapeman, Cathleen; McConnell, Laura; Rice, Clifford; Walter F. Schmidt. New technologies to facilitate examination of pollutant degradation pathways in environmental matrices.

    UNIVERSITY OF ARKANSAS, Guangyao Sheng, John D. Mattice, Briggs W. Skulman, Yuan Chun, Yaning Yang, Ping Zhang. Studies included: (1) Adsorptivity of Aged Crop Residue-Derived Soil Chars for Pesticides; (2) Reduced Biodegradation of Pesticides in Soil Containing Crop Residue-Derived Chars. Chars arising from the burning of crop residues are potentially effective adsorbents for pesticides in agricultural soils. Wheat char aged in soil was highly effective in adsorbing diuron. As crop residues are frequently burned in the field, pesticides in agricultural soils may be highly immobilized due to the presence of chars.

    UNIVERSITY OF GEORGIA, Kang Xia. Studies included: (1) Occurrence pharmaceuticals and personal care products in biosolids; (2) Photodegradation of endocrine disruptor, 4-nonylphenol, in biosolids-applied soil; (3) Removal of 4-NP from biosolids through composting; (4) Dynamics of soil microbial communities exposed to Pb and 2, 4, 6-trinitrotoluene (TNT) mixtures. A range of pharmaceuticals and personal care products were identified and detected in the biosolids at concentrations from ug kg-1 to mg kg-1. 4-nonylphenol (4-NP), a non-naturally occurring endocrine disruptor, is one of the most detected organic chemicals. Its level was detected at as high as 1400 mg kg-1. Sunlight plays an important role in degrading 4-nonylphenol in biosolids. Surface application of biosolids on wet soil on sunny days (rather than soil incorporation) could be effective in reducing biosolids-associated organic chemicals that can be degraded through photolysis reactions.

    UNIVERSITY OF CALIFORNIA-RIVERSIDE, W.J. Farmer and J. Gan. Studies included: (1) Decontamination of Halogenated Pesticides; (2) Pesticide Chirality; (3) Bioavailability of Synthetic Pyrethroids; (4) Influence of Soil Microstructure on the Molecular Transport Dynamics of 1,2-Dichloroethane. We measured the reaction rate constants for the reaction between sodium tetrasulfide with 1,3-dichloropropene, methyl iodide, chloropicrin, alachlor, metolachlor, propachlor, and acetochlor. Analysis of reaction kinetics and initial products showed that the reaction was SN2-type nucleophilic substitution, in which sulfur dianions replace the halide in the pesticide molecule. The overall reactivity of tetrasulfide toward these halogenated fumigants was 3-1425 times as strong as for thiosulfate. Our preliminary observations suggest that polysulfides may effectively transform a great number of environmentally significant halogenated organic compounds, and this reaction may hold a great promise to be used for remediation or waste treatment.

    UNIVERSITY OF CALIFORNIA-BERKELEY, G. Sposito, B. Toner, M. Villalobos. Identify mechanisms and products of atrazine degradation by manganese oxides. Manganese oxides are known to transform atrazine under laboratory conditions. Research during 2003 focused on the production and characterization of a biogenic manganese oxide with which to react atrazine. Our results for the Mn oxide produced by Pseudomonas putida strain MnB1 agree with the properties reported for freshly-precipitated, natural Mn oxides found in oxic/anoxic zones, providing further support for the predominance of biological Mn(II) oxidation in these environments.

    OBJECTIVE 2: Integrate chemical and biological process information for use in models applicable across different spatial and temporal scales.

    UNIVERSITY OF HAWAII-MANOA, P. Ray. Studies included: (1) Simulation of contaminant transport from surface water to wells located on riverbanks during flood periods; (2) Assessment of the vulnerability of farmstead and rural domestic wells to agrichemical contamination; (3) Transport of pathogens and selected pharmaceutical compounds in Hawaiian Oxisols. Research results from this objective helps in the assessment of the quality of drinking water where mandatory testing of water quality is not needed. In addition, the validated models serve as tools to predict contamination at sensitive settings.

    ARS-USDA GEORGE E. BROWN SALINITY LABORATORY, RIVERSIDE, CA, S. Yates and S. Papiernik. Simulating control of plant pathogens after soil fumigation was studied.

    OBJECTIVE 3: Provide stakeholders with tools for developing strategies to ensure sustainable agriculture and to protect natural resource systems.

    UNIVERSITY OF HAWAII-MANOA, P. Ray. Studies included: (1) Chemical Leaching and Evaluation of Risk System (CLERS); (2) Demonstration of bromacil leaching under reduced application rates; (3) Leaching of Selected Chemicals in Various Hawaii Soils. Computerized software, graphical user interface, and data provide the stakeholders with a tool to assess the impact of land management practices on drinking water and ground water quality. Field evaluation of pineapple yield under less than the label rates of pesticides (especially bromacil) will reduce the potential for ground water contamination.

    ARS-USDA GEORGE E. BROWN SALINITY LABORATORY, RIVERSIDE, CA, S. Yates and S. Papiernik. Studies included: (1) Effect of Application Variables on Emissions of Fumigants Applied via Subsurface Drip Irrigation; (2) Effect of Surface Tarp on Emissions and Distribution of Drip-Applied Fumigants.

    UNIVERSITY OF CALIFORNIA-RIVERSIDE, W.J. Farmer and J. Gan. Pesticide Runoff from Nursery Sites and Mitigation - We directly work with stakeholders to help them meet water quality requirements and to comply with such regulations as TMDLs. Our clientele include commercial nurseries in southern California, the Regional Water Quality Control Boards, State regulatory agencies (Department of Pesticide Regulation and Department of Food and Agriculture), and county/city water quality managers. The research results may be used for implementing pesticide TMDLs, and improving water quality in impaired waterbodies in urban and suburban watersheds.

    Impact Statements:
    1. We have developed methodology to allow prediction of pathogen control prior to soil fumigation, in which a model is used to describe the fate and distribution of fumigant in soil, emissions into the atmosphere, and survival and destruction of common soil pathogens.
    2. Antibiotics used in animal production are excreted in the urine and feces, which are commonly applied to agricultural fields after an incubation period in a manure pond. Our studies on tetracylcines, tylosin, and carbadox show that these compounds are highly sorbed to soils, thus their most likely entry into water bodies will be through spills, surface runoff, erosion, preferential flow, and facilitated transport.
    3. Wheat char arising from the burning of crop residues in soil was highly effective in adsorbing diuron. As crop residues are frequently burned in the field, pesticides in agricultural soils may be highly immobilized due to the presence of chars.
    4. A non-naturally occurring endocrine disruptor, 4-nonylphenol (4-NP),is one of the most detected organic chemicals in biosolids. Because sunlight plays an important role in degrading 4-NP in biosolids, surface application rather than soil incorporation of biosolids on wet soil on sunny days could be effective in reducing biosolids-associated organic chemicals that can be degraded through photolysis reactions.
    5. Our work has indicated that several approaches, including application of fumigants with water, use of virtually impermeable surface tarps, application deep in soil, and construction of a highly reactive zone at the soil surface, can be effective in reducing atmospheric emissions of fumigants
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    Date of Annual Report: 02/14/2005

    Report Information:
  • Annual Meeting Dates: 10/14/04 to 10/16/04
  • Period the Report Covers: 10/2003 to 09/2004

    • Participants:
    Brief Summary of Minutes of Annual Meeting:
    The (second) 2004 W-82 meeting was held October 14-16, 2004, at the Connecticut Agricultural Experiment Station, New Haven, CT. The meeting was hosted by Joe Pignatello. Eight scientists, plus the group's administrative adviser, Lee Sommers, and the group's CSREES contact, Nancy Cavallaro, attended the meeting. The meeting was called to order by Michael Thompson. Nancy Cavallaro presented an update on funding and priorities for the USDA's National Research Initiative. Lee Sommers presented a time line for preparation, review, and approval of a new multistate project, as well as advice on how to target the new proposal. A significant part of the business meeting was devoted to discussions about the nature and goals of a multistate research committee and how to write an effective proposal. A "writing" subcommittee composed of Michael Thompson, Linda Lee, and Mark Radosevich was appointed to solicit contributions to the new proposal from current W-82 members and to draft a proposal. A goal of submitting the new proposal in January 2005 was adopted. The meeting also included presentations of research reports by all participants. Sharon Papiernik was elected chair for the next W-82 meeting, and Mark Radosevich was elected secretary. Pending approval of the new project proposal, the next meeting will be hosted by Mark Radosevich at the University of Tennessee, Knoxville, at a date to be announced. At that meeting, a new slate of officers will be elected for the coming years.

    Accomplishments:
    OBJECTIVE 1: Characterize and quantify the basic chemical and biological processes controlling the behavior of pesticides, other organic chemicals, and microorganisms in soil, water, and air.

    SOUTH DAKOTA STATE UNIVERSITY, BROOKINGS, SD, Sharon Clay, Zhuojing Liu, Jared K Oswald, Todd P Trooien, Robert Thaler. Studies included: Assessing the potential transport of tylosin in the landscape. Tylosin, an antibacterial chemical used in livestock production, is highly water soluble, only partially sorbed to manure, and potentially excreted by animals that receive it in their feed. A small sprinkler infiltrometer was used to measure infiltration rate at three landscape positions in a field. Results show that tylosin can be transported in runoff. In areas where manure that contains tylosin is applied to fields, runoff reduction or prevention measures may be required to prevent tylosin from reaching surface water resources.

    GEORGE E. BROWN SALINITY LABORATORY, Scott R. Yates, Wei Zheng, and Sharon Papiernik. Studies included: (1) Transformation of Chloropicrin and 1,3-Dichloropropene by Metam Sodium in a Combined Application of Fumigants, (2) Leaching Potential of Persistent Soil Fumigant Residues. The effect of dissolved organic matter (DOM) and ammonium thiosulfate (ATS) amendments on the leaching potential of persistent soil fumigant residues was evaluated. DOM did not promote the leaching of persistent fumigant residues, and ATS remarkably reduced the amount of 1,3-D and CP, yet notably increased MITC recovered in the effluents. The results suggest that the leaching of persistent fumigant residues through soil to water is significant, and movement of fumigants in soil is not facilitated by DOM. Amending soil with ATS through irrigation is an effective method to remove persistent residues of halogenated fumigants.

    IOWA STATE UNIVERSITY, AMES, IOWA, M.L. Thompson, D. A. Laird, M.A. Chappell, L.S. Sonon. Studies included: (1) Sorption of Formulated Atrazine by Soil Materials, (2) Sorption of a Nonionic Polyoxyethylene Lauryl Ether Surfactant by 2:1 Layer Silicates. Atrazine sorption to soil was evaluated in the presence of varying concentrations of a surfactant. In general, the surfactant inhibited atrazine sorption, but in some cases, high concentrations of surfactant enhanced atrazine sorption. The type and concentration of surfactant used in atrazine applications can influence the mobility of atrazine in the soil.

    USDA-AGRICULTURAL RESEARCH SERVICE, ST. PAUL, MN, W. Koskinen. Studies included: (1) Sorption-desorption of "aged" isoxaflutole and diketonitrile degradate in soil, (2) Interactions of a diketonitrile degradate of isoxaflutole with organoclays. We determined the changes in distribution between soil bound and solution phases of the main metabolite of the herbicide isoxaflutole, a diketonitrile degradate, with incubation time. We found that while the herbicide metabolite slowly degraded in soil, the remaining chemical became more tightly bound to some soils. These results are further evidence that increases in binding of the pesticide to soil during pesticide aging should be taken into account during characterization of the environmental fate of pesticides.

    CONNECTICUT AGRICULTURAL EXPERIMENT STATION, NEW HAVEN, CT, Joe Pignatello, Yuefeng Lu, Don Zhu, Michael Sander, Seoukjoon Kwon, Jun Li. The work in 2004 dealt with (1) sorption irreversibility, (2) pi-pi electron donor-acceptor interactions between aromatic compounds and complementary functional groups in natural organic matter, and (3) bioavailability of contaminants in soil and sediment. To more fully characterize the sorption of organic compounds to natural organic matter (NOM) substances we have investigated history-dependent sorption behavior. We found that a) isolated, purified soil humic acid behaves like a glassy solid; b) metal-ion crosslinking creates a more rigid-chain structure and supports a link between nonideal sorption and the glassy character of soil organic matter; and c) metal ions influence the structure of humic materials and therefore the sorption of hydrophobic organic compounds. Nonlinear and irreversible behavior may be expected for macromolecular forms of NOM that are in a glassy state, and emphasize the case that NOM is not a passive sorbent, but may be physically altered by the sorbate.

    PURDUE UNIVERSITY, W. LAFAYETTE, IN, L.S. Lee, R.F. Turco, M. Bischoff, S. Sassman, S. Rao. Studies included: (1) Fate of Animal Hormones, (2) Fate of Pharmaceuticals, (3) Fate of Industrial Chemicals. (4) Remediation, (5) Bioavailability of Sorbed Organic Chemicals. Our studies on tetracyclines, tylosin, and carbadox show that these compounds have relatively short half-lives and are highly sorbed to soils. Therefore, total amounts of antibiotics getting to waterways are likely to be small, and their most likely entry into water bodies will be through inadvertent spills, surface runoff, erosion, preferential flow, and facilitated transport.

    UNIVERSITY OF TENNESSEE, KNOXVILLE, TN, Mark Radosevich. Studies included: Environmental Fate of Formaldehyde During Decomposition of Land Applied Engineered Wood Products. Tennessee requires medium density fiberboard (MDF) and plywood waste to be placed in landfills rather than recycled because these products contain formaldehyde. Soil microcosm studies revealed rapid degradation of MDF. Addition of MDF to soil resulted in no apparent decrease in nitrogen availability. These results suggest that land application of MDF is an effective and beneficial method of recycling this engineered material.

    THE UNIVERSITY OF GEORGIA, ATHENS, GA, Kang Xia. Studies included: (1) Removal of 4-NP from biosolids through composting, (2) Dynamics of soil microbial communities exposed to Pb and 2,4,6-trinitrotoluene mixtures. Our research has shown that 4-nonylphenol (4-NP) appears in biosolids at a wide concentration ranges, from several mg kg-1 to several thousands mg kg-1. A pilot scale laboratory-controlled composting experiment was conducted to investigate the effectiveness of 4-NP removal through mixing biosolids with wood shavings at different environmental conditions. This investigation provided further evidence that 4-NP can be effectively degraded during composting.

    UNIVERSITY OF CALIFORNIA, RIVERSIDE, CA, W.J. Farmer, J. Gan, W.P. Liu, S. Bondarenko, W.C. Yang. Studies included: (1) Decontamination of Halogenated Pesticides, (2) Pesticide Chirality, (3) Bioavailability of Synthetic Pyrethroids, (4) N2, CO2, and 1,2-dichloroethane as molecular probes of soil microstructure. Decontamination methods are needed for the removal of fumigant residues in the environment. In this study, we investigated the dehalogenation of several halogenated fumigants by reaction with polysulfides. This research may have directly applicable outcomes as it contributes to the potential development of selective remediation/decontamination methods. As the reaction dehalogenates the pesticide, it is expected that the pesticide is detoxified.

    TEXAS A&M UNIVERSITY, Scott A. Senseman. Studies included (1) Dendritic surfactants and organoclay morphology, (2) sorption of atrazine and its degradation products in vegetated filter strips, (3) Effects of Roundup on microbial activity and biomass (4) photocatalytic degradation of picloram with titanium dioxide in water.

    OBJECTIVE 2: Integrate chemical and biological process information for use in models applicable across different spatial and temporal scales.

    UNIVERSITY OF HAWAII AT MANOA, Chittaranjan Ray. Studies included: (1) Simulation of contaminant transport from surface water to wells located on riverbanks during flood periods, (2) Assessment of the vulnerability of farmstead and rural domestic wells to agrichemical contamination, (3) Transport of pathogens and selected pharmaceutical compounds in Hawaiian Oxisols. We investigated the effect of high molecular polymers (such as polyacrylamides, used for erosion control) on the transport of pathogens (E. coli and MS-2 page) in soil columns of Wahiawa Oxisols. The Oxisols studied act as sinks for bacteria and viruses. High clay content, low pH, high iron oxide content, and a low solution pH contribute high rates of pathogen retention in these soils.

    GEORGE E. BROWN SALINITY LABORATORY, Scott R. Yates, Wei Zheng, and Sharon Papiernik. Studies included: Effect of Soil Moisture and Irrigation on Propargyl Bromide Volatilization and Movement in Soil. We studied the volatilization and movement of propargyl bromide (3BP), a potential replacement for the soil fumigant methyl bromide, under different irrigation treatments. We found that volatilization was about three times greater from non-irrigated soil. Irrigation and higher initial soil moisture content were more effective in controlling 3BP volatilization than the use of a tarp. Short advective gas and liquid fluxes created by the irrigation had pronounced and prolonged effect on 3BP distribution and degradation. Henry's law could not be used to predict the 3BP distribution pattern in the liquid phase even long after the irrigation ceased.

    OBJECTIVE 3: Provide stakeholders with tools for developing strategies to ensure sustainable agriculture and to protect natural resource systems.

    UNIVERSITY OF HAWAII AT MANOA, Chittaranjan Ray. Studies include: (1) Chemical Leaching and Evaluation of Risk System (CLERS), (2) Demonstration of Bromacil leaching Under Reduced Application Rates, (3) Leaching of Selected Chemicals in Various Hawaii Soils. A physically based model is used to calculate leaching characteristics of pesticides based upon soil physical/chemical properties, depth to water, recharge rate, and pesticide properties. The model will be used by the Hawaii Department of Agriculture and pesticide registrants to evaluate relative attenuation of pesticides. We have completed the detailed evaluation 13 new chemicals where the registrants sought their use in Hawaii.

    GEORGE E. BROWN SALINITY LABORATORY, Scott R. Yates, Wei Zheng, and Sharon Papiernik. Studies include: (1) Effect of Surface Tarp on Emissions and Distribution of Drip-Applied Fumigant, (2) Effect of Application Variables on Emissions of Fumigants Applied via Subsurface Drip Irrigation. Application of fumigants through drip irrigation has been proposed as a means to decrease fumigant emissions, improve fumigant distribution in soil, and minimize worker exposure. These experiments were conducted to investigate the effect of the configuration of the drip system on the volatilization and distribution of the fumigants 1,3-dichloropropene, propargyl bromide, and methyl isothiocyanate in bedded systems. Results indicated that changing the drip emitter spacing and using multiple drip lines in each bed had little effect on the emissions and distribution of any fumigant.

    UNIVERSITY OF CALIFORNIA, RIVERSIDE, CA, W.J. Farmer and J. Gan. Studies include: Pesticide Runoff from Nursery Sites and Mitigation. In close collaboration with nursery growers in Orange County and Ventura County, we have carried out studies to understand the source, fate and distribution of pesticides in nursery runoff, and to develop best management practices (BMPs) to reduce pesticide load in the runoff. We have also worked closely with the State Water Resources Control Board, the Regional Boards, and California Department of Pesticide Regulation to extend the technology to nursery growers through many forms of public outreach and education activities, including training workshops for growers and pesticide applicators, and publication of fact sheets and newsletter articles.

    Impact Statements:
    1. PATHOGEN TRANSPORT. Oxisols generally act as sinks for bacteria and viruses. We found that adding polyacrylamides to the surface of soils where wastewater is to be applied did not significantly promote transport of E. coli or MS-2 phage through the soil. Similarly, a sewage-derived surfactant did not promote mobility of the bacterium or virus in the soil. High clay content, low pH, high iron oxide content, and a low solution pH contribute high rates of pathogen retention in these soils.
    2. COMBINED APPLICATION OF FUMIGANTS. Combined application of fumigants is a potential strategy to replace methyl bromide in the control of soil-borne pests. Simultaneous application of metam sodium with chloropicrin or 1,3-D accelerated the transformation of the two halogenated fumigants, reducing their availability in soil. A sequential strategy for multiple fumigants was developed, which could be applied without the loss of active ingredient that occurs due to the reaction between fumigants.
    3. LIMITING HERBICIDE MOVEMENT WITH ORGANOCLAYS. The off-site movement of highly mobile herbicides that are accidentally spilled can be decreased by incorporating an appropriate sorbent in the affected area. We studied the herbicide isoxaflutole and its main breakdown product, a diketonitrile (DKN) and determined why DKN is not released from the clay particle. These results will aid scientists in their development of inexpensive and efficient organoclays to be used to decontaminate spill sites.
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