Duration: 10/01/2010 to 09/30/2015

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Statement of Issues and Justification

Agricultural production can result in the contamination of soil, air, and water resources. Identifying and quantifying the physical, chemical, and biological processes that control the behavior of organic chemicals in the environment is imperative for improving management of agrochemicals, minimizing contamination of natural resources, and remediating currently contaminated environments. This research project will address two significant issues: (1) the persistence and availability in the environment (including bioavailability, transport, uptake, and degradation) of pesticides used in agricultural production and (2) the fate of organic and nanoparticle contaminants applied to soil found in animal manures, biosolids and wastewater.

Because of the potential for contamination it is critical that chemicals are employed in ways that minimize contamination risks and that environments currently contaminated with organic chemicals be effectively remediated. Evaluating and quantifying the behavior of organic chemicals in soil and water is vital for the development of sound strategies that ensure sustainable agriculture by protecting natural resources through minimizing contamination risks and implementing effective remediation practices.
About 2 billion kilograms of chemicals are used as pesticides each year in the U.S., with agricultural usage accounting for ~77% (Aspelin and Grube, 1999). Although it is likely future pesticide use will decline as a result of improved integrated pest management strategies, pesticides will remain a component of many production systems. Research is needed to optimize pesticide efficiency with minimal environmental impacts. Newly developed pesticides, many of which are applied at rates one-tenth or less those of conventional pesticides, are often highly toxic to nontarget crops or aquatic organisms; thus, considerable knowledge of the transport and fate of these substances is needed as well.
The environmental fate of pharmaceutically active compounds (PhACs) such as antibiotics, hormones, drugs and other compounds capable of endocrine disruption is also a growing concern. For example, animal farms in the U.S. are estimated to release 54.5 Mg of hormones per year, most of which (49 Mg) are estrogenic hormones; the remaining 5.5 Mg are androgenic hormones, such as testosterone (Lange et al., 2002; Jacobsen et al., 2005). In addition to animal feeding operations urban wastewater is increasingly being seen as a source of PhACs in soil. Municipal wastewater is used for irrigation in agricultural crop production as well turf operations. Kinney et al (2006) reported that the use of reclaimed wastewater for irrigation of turf resulted in the presence of a number of pharmaceutical compounds in soil although no net accumulation was observed in the top 30 cm. This indicates that natural inactivation and removal of the compounds was occurring through degradation, sorption, or a combination of both. Recent work by members of this committee indicates that both naturally occurring and pharmaceutically based estrogens, as well as a widely used pharmaceutical compound, can accumulate in soils under conditions of wastewater irrigation. Being only a recent area for research, many questions remain concerning the environmental and human health impacts of PhACs and their transformation products existing in soil.

Antibiotics are used in the livestock industry for therapeutic treatment of sick animals, illness prevention (prophylactic use), and to enhance growth rates and increase feed efficiency (Wegener, 2003). Using current drug delivery practices, studies have shown that 30  80% of an antibiotic dose can rapidly pass through the G.I. tract of an animal in an unaltered state (Elmund, et al., 1971; Levy, 1992;). Subsequently, antibiotics present in animal manure are introduced into agricultural ecosystems via land application of animal waste. The presence of these compounds in the environment may adversely impact soil microbial communities, diminish water quality, and increase the spread of antibiotic resistant bacteria (Daughton and Ternes, 1999; Sarmah et al., 2006; Lee et al., 2007; Aga, 2008). The aforementioned concerns highlight the need to mitigate the loss of antibiotics from agroecosystems and maintain environmental quality.

Nanotechnology is a new technology that offers a wide range of applications including consumer products, remediation of contaminated soil and water, medical imaging, and targeted drug delivery. It is projected to become a $1 trillion market by 2015 (Nel et al., 2006). The behavior and effect of nanoparticles in the environment are poorly understood. It is important to determine basic fate and transport characteristics of nanoparticles as well as unintended effects they may have on native biota in order to ensure that nanotechnology implementation can be realized with minimal impact on the environment.

In addition to specific pesticides and contaminants applied to soils other organic chemicals related to agriculture are also of interest. For example, petroleum products are commonly used on farms and "inert" materials (e.g., solvents and emulsifiers) are often present in pesticide formulations. Fundamental studies of the behavior of model organic compounds can help us understand the mechanisms by which more complex compounds interact with solid, solution, and vapor phases in the environment. Both urban and rural sectors of the economy can benefit from basic and applied studies of organic chemicals whether they are used in agricultural production, in home gardens and lawn care, or enter the environment through regulated or unregulated waste disposal.
The fate and accumulation of organic compounds and their degradation products are mediated by various -- often tightly coupled -- processes, including advection and diffusion, sorption and desorption, biodegradation, and chemical reactions. These processes occur within and between intimately associated environmental compartments (soil, water, air, and biota). For example, pesticide interactions with the soil regulate persistence, release into water and air, and bioavailability, which in turn impact pesticide efficacy, degradation, and off-site transport. Because the interactions between organic chemicals and environmental media are so complex and occur at disparate spatial and temporal scales, research involving environmental pollution requires a multidisciplinary approach.

A unique strength of this research project is the collaboration among its members from different scientific disciplines whose research benefits from the opportunity to communicate with one another on a regular basis through this project. This project provides a forum where specialists in mechanisms of chemical behavior, microbial ecology, transport behavior, mathematical modeling, and field assessment techniques can exchange information gleaned from individual research efforts as well as work on collaborative projects. Such cooperative efforts among research groups representing different kinds of expertise and diverse geographical areas are imperative to develop appropriate management techniques for minimizing environmental contamination and risk.

The long-term goal of this project is to minimize environmental contamination from pesticides, pharmaceuticals, and related organic chemicals and nanoparticles. We propose to conduct a cooperative research program that elucidates fundamental mechanisms of chemical behavior and applies this knowledge at multiple spatial and temporal scales. In combination with mechanistic models, the principles of chemical behavior will be incorporated into management models. Research conducted will be useful in the continued development of best management practices for minimizing environmental contamination, as well as in the development of efficient and comparatively inexpensive strategies for remediating contaminated environments. Results of the research conducted by members of this multistate project group will be applicable to both agricultural ecosystems and to urban systems. Thus it will help to fulfill USDA goals to enhance protection of soil and water resources across a range of agricultural ecosystems. By developing better management techniques, the risks of adverse environmental and health effects of contaminants will be minimized.

Related, Current and Previous Work

Sorption/Desorption

Committee members have played a leading role in elucidating mechanisms of sorption of agricultural organic chemicals and in refining methodologies for studying sorption processes. They have access to equipment needed to pursue the questions addresses by this proposal and have experience with the methods utilized. Members of the committee have identified gaps which remain in our knowledge of adsorption-desorption processes in soil,and which significantly affect our ability to manage pesticide and other organic chemical and nanoparticle use,to optimize remediation strategies,and to define ecologically acceptable endpoints. Knowledge gaps include the effect of aging on sorption-desorption,the sorption characteristics of PhACs and the effect of biochar on sorption-desorption.

Aging

Effects of aging on sorption-desorption have been shown in both short-term and long-term batch studies. Numerous studies using traditional batch equilibration method have shown a hysteresis effect during desorption of the pesticide from soil. Hysteresis has also been shown to increase with aging (Koskinen et al 1979). Using the batch sequential extraction method for long-term aged pesticide residues,increases in the sorption coefficient Kd with incubation time have generally been observed for diverse pesticides (Boesten and Van der Pas 1983;Pignatello and Huang 1991;McCall and Agin 1985;Walker 1987;Shelton and Parkin 1991;Walker 1987;Blair et al 1990;Gaillardon and Sabar 1994;Cox et al 1998;Koskinen et al,2001;Pignatello and Huang 1991;Bresnahan et al 2000;2002;Koskinen et al 2002;2003;Regitano and Koskinen 2008). The increase in sorption Kd in aged soil has been reported to be up to a factor of 8 as compared to that in freshly treated soil.

Hormones

Concentrations of estradiol (with its main metabolite estrone) and testosterone can vary within one type of animal production. In broiler litter they range from 14 to 65 µg kg-1;and those of testosterone peak at 133 µg kg-1,whereas 8 times more estrogen and about twice as much testosterone have been found in breeder litter (Hemmings and Hartel,2006;Shore et al,1993). The concentration of testosterone in an irrigation pond and a local stream near a field that received poultry litter,were much lower than the levels in the litter source,ranging from 0.5 to 5 ng L-1 and 1 to 28 ng L-1,respectively (Casey et al,2003,2004;Shore et al,1995a,1995b). ELISA analysis of runoff from fields spread with poultry manure,have shown estradiol and testosterone concentrations ranging between 10 and 2300 ng L-1 (Finlay-Moore et al,2000;Lee et al,2003). Peterson et al (2000) reported that spring water adjacent to fields amended with poultry and cattle manure contained 6 to 66 ng L-1 of 17²-estradiol. Aqueous extracts from composted chicken layer manure have shown rapid losses of 17²-estradiol and testosterone with time,but both hormones were still able to be extracted (1 to 3 ng g-1) at the conclusion of composting (Hakk et al,2005). Research indicates high sorption on soil matrices (Lee et al,2003;Das et al,2004;Casey et al,2005) and high degradation rates by soil microorganisms and other factors,such as retardation within soil materials (Lorenzen et al,2005). Nevertheless,hormones are consistently detected in surface water and groundwater (Falconer et al,2006;Kolpin et al,2002;Ying et al,2002).

Most work related to the sorption behavior of hormones has not been conducted at low concentrations relevant to environmental soil and water samples. Published sorption studies (Casey et al,2005;Das et al,2004;Lee et al,2003;Ying and Kookana,2003),consider hormone concentrations which span the range of relatively high concentrations reported for animal manures. Sorption at hormone concentrations comparable with the relatively low levels determined in surface water and groundwater samples are practically an unexplored area in terms of sorption studies. Until recently,high limits of detection have required use of high hormone concentrations in experimental studies (Lee et al,2003). The development of more precise analytical methods,such as mass spectrometric techniques (Gentili et al,2002;Hanselman et al,2006;Lagana et al,2000;Yamamoto et al,2006), allows for determining hormone concentrations at <1.0 ng L-1. Participants in this project will explore the question of hormone sorption across the full span of relevant hormone concentrations ranging from typical hormone concentrations in surface water,groundwater,or manure-unamended soil (0.02 to 50 ng L-1),to typical concentrations in runoff waters (10 to 2,000 ng L-1),to animal manures (300 to 150,000 ng L-1),and to a maximal possible water concentration (~1,000,000 ng L-1 (Colucci et al,2001;Ying et al,2002;Fine et al,2003;Lorenzen et al,2004,2005;Shappell,2006;Shareef et al,2006).

In general, adsorption is faster than desorption - a phenomenon known as hysteresis. Organic chemicals show increasing hysteresis with increasing time that they reside in soil. Aging of hormones is currently ascribed to a physical immobilization phenomena (Alexander,1995;Xing and Pignatello,1997;Lueking et al,2000;Zhu and Selim,2000) referred to as sequestration or slow sorption. Consequently,sequestered compounds will not desorb into soil solution as readily as those adsorbed on external surfaces. A separate category of immobilized chemicals are so-called bound residues (Alexander,1995). Unlike sequestered compounds,bound residues are formed by covalent binding of organic chemicals to soil organic matter. In living organisms (plants,animals),an analogous process is hormone deactivation through conjugation. Bound chemicals show some release when subjected to microbial activity (Dec et al,1997) nevertheless their toxicity is severely reduced (Alexander,1995;Alexander,2000).

Antimicrobials

Studies have investigated the fate and transport of veterinary antibiotics in the environment (e.g.,Wang et al,2006;Sassman and Lee,2007;Dolliver et al,2008;Wang and Yates,2008);however,none have focused on the degradation of these compounds in the rhizosphere of vegetative buffers. Similarly,studies have been conducted to investigate the sorption of veterinary antibiotics to soil (Thiele-Bruhn et al,2004;Figueroa and MacKay,2005;MacKay and Canterbury,2005;Sassman and Lee,2005;Allaire et al,2006),although no studies have investigated antibiotic sorption to vegetative buffer soils.

Very little research has been conducted to elucidate the influence of manure-derived dissolved organic matter on antibiotic sorption to soil (Kay et al,2005). Dissolved organic matter (DOM) in surface runoff from pastures has been measured in the range of 10-25 mg C L-1 (Fleming and Cox,2001;Tate et al,2004). These organic compounds may enhance the co-transport of antibiotics from areas where manure is deposited and into vegetative buffers. DOM may enhance or decrease the sorption of antibiotics to vegetative buffer soils. Therefore,there is a need to further understand veterinary antibiotic sorption processes in vegetative buffer soils prior to conducting field trials and recommending use of this land management practice for reducing loss of veterinary antibiotics from agroecosystems.

Human Drugs

Recently,40 different rivers and streams in Germany were found to contain 31 different pharmaceutical compounds (Ternes,2001). It was also found that at least one compound was found in every sample. In North America a survey of 139 streams found 80% of streams sampled contained at least one target compound (Kolpin et al 2002) and that an individual sample contained 86% of the target compounds analyzed for. Further analysis of individual streams by Kolpin et al (2004) indicated that a major source of pharmaceuticals found in surface waters were a result of treated sewage effluent inflows to streams and rivers. These results and others (Castiglioni et al,2006) indicate that a major source of pharmaceuticals found in environmental water samples originate from municipal sources.

Irrigated soils have been shown to offer a biologically active zone where the oxygen status of the micro environment can change from aerobic to anaerobic depending on moisture status (Luxmoore et al 1970). This changing environment can potentially result in differences in the persistence for a compound such as carbamazepine. Kinney et al found that the total mass of many pharmaceutical compounds in soils irrigated with reclaimed water increased over a growing season (2006). Their data also indicated that throughout the winter when there was no irrigation the concentration of the pharmaceutical compounds was reduced. It was postulated that the reduction over the winter was due to precipitation leaching the compounds below 30 cm. However,recent sorption data would suggest that some of the compounds would be classified as non-mobile (Williams et al,2006). It is therefore important to better understand the potential mobility of human drugs in soil.

Biochar

Burning biomass in the absence of oxygen (pyrolysis) yields three products: a liquid (bio-oil),solid (BioChar),and a gas (syngas) (Bridgwater,2003). The recalcitrance of the BioChar suggests that it could be a viable carbon sequestration strategy,however the increased sorption may result in the need for increased application of some soil applied herbicides in order to preserve their efficacy on BioChar amended soils. Recently,pyrolysis has been seen as a way to sequester carbon as a means to reduce atmospheric CO2 concentrations. Thus there is a potential for vast quantities of BioChar to be added to soil. A prerequisite to the widescale use of BioChar as a soil amendment in agriculture,therefore,is a thorough assessment of its effects on the biological availability of agriculturally important chemicals.

BioChars are expected to be highly surface-active materials that strongly adsorb organic compounds. The surface area of BioChar may range up to 400 m2/g depending on source material and conditions of formation. Much of this surface area is hydrophobic and located in micropores where the adsorption potential for organic compounds is especially great compared to larger pores and flat surfaces. A number of organic chemicals including pesticides,soil contaminants arising from current or past land use practices,and natural signaling chemicals among plants and other species (allelochemicals). Adsorption governs bioavailability,which,in turn,controls the beneficial or harmful effects,as the case may be,of soil-borne chemicals. In view of the potential role of BioChar as a potent adsorbent of agriculturally important chemicals have to be carefully considered.

The addition of BioChar to soil may reduce the bioavailability of pesticides,requiring the use of higher application rates to achieve the same degree of pest control (Yu et al 2009) On the other hand,BioChar may reduce pesticide leachability,which is a benefit. Modern agricultural practices introduce a variety of unwanted contaminants to soils that represent a potential threat to human and ecological health depending on their toxicity and bioavailability to crops and foraging animals. About half the quantity of antibiotics and nearly all the quantity of growth hormones produced in the United States are used in agriculture,a large fraction of which are ultimately applied to fields. A survey (Harrison et al,2006) of treated and untreated municipal solid waste identified 516 anthropogenic chemicals,111 of which are on the U.S. Environmental Protection Agencys (EPAs) list of 126 priority pollutants. In addition,legacy pesticides remaining in many fields such as chlordane and DDT are of significant concern. The addition of BioChar to soils can reduce the bioavailability of incidental soil contaminants toward plants and foraging animals. Carbon arising from cane leaf burning was shown to affect sorption of herbicides in sugar cane soils (Hilton and Yuen,1963). Ash from burning wheat (Sheng et al,2005;Yang and Sheng,2003a;Yang and Sheng,2003b),and rice (Yang and Sheng,2003b),have been reported to increase sorption of a number of herbicides. Charcoal added to soils has been reported to increase herbicide sorption (Yamane and Green,1972;Yu et al,2006). The addition of BioChar to soil increased the sorption of atrazine and acetochlor compared to non-amended soils,resulting in decreased dissipation rates of these herbicides (Spokas et al,2009).

Biodegradation

A central issue in both bioremediation and risk assessment of soil containing residues of agricultural chemicals is the bioavailability of residual forms of the contaminants in these media. The physical process of sorption may remove molecules from direct access by organisms that are too small to penetrate soil nanopores and organic matter phases. The concentration of molecules in the soil solution where they can be readily accessed by cells may be limited by molecular diffusion from remote sorption sites within soil particles. Moreover,physical changes in the sorbent can lead to molecular entrapment in pores. The result may be a significant fraction of the pesticide that strongly resists both desorption and biodegradation. Several studies have shown that the bioavailability of atrazine decreased as soil-atrazine contact time increased (Chung and Alexander,1998;Kelsey et al,1997;Sharer et al,2003).

Generally,soil-sorbed organic contaminants and pesticides have been considered unavailable for biodegradation without prior desorption (Ogram et al,1985;Squillace and Thurman,1992). However,some evidence suggests that that desorption into bulk solution is not a prerequisite for biodegradation (Guerin and Boyd,1993;Calvillo and Alexander,1996;Tang et al,1998;Feng et al,2000;Park et al,2001,2002). Possible mechanisms that allow microbial access to sorbed contaminants include production of biosurfactants,local alterations of soil organic matter by the biofilm causing release of sorbed chemicals,and creation of steepened concentration gradients by the biofilm near the solid surface. Exploration of these mechanisms can help us find new ways to increase the bioavailability of aged pesticides in contaminated soils and sediments,thereby enhancing remediation efforts.

Antimicrobial Resistance

The USEPA estimated that in 1998,13.7 million kg of antimicrobials were used in the United States. Though antibiotics are commonly used at therapeutic levels in humans and livestock to treat disease,livestock often receive applications at sub-therapeutic levels to increase feed efficiency and improve growth rates (Cohen,1998). Many antimicrobials are poorly absorbed in digestive tracts and can be detected in human and animal waste in significant quantities (Elmund et al,1971;Feinman and Matheson,1978) and from there can be transferred into the environment. In a national reconnaissance,antimicrobials were detected in 27% of U.S. streams and rivers (Koplin et al,2002). Furthermore,antibiotics have been found at several meter depths and in groundwater (Hirsch et al,1999;Batt et al,2006;Swartz et al,2006).

The levels of antimicrobials found in the environment are low and often below acute effects (Webb et al,2003),but issues of aggregate and cumulative exposures and ecotoxicology are not well known and remain of concern (Daughton and Ternes,1999). The principal existing concern with antibiotics is the identification of growing resistance in microbial populations in the environment (Schwartz et al,2006;Gilchrist et al,2007). Antimicrobial resistant bacteria have been found in surface water (Schwartz et al,2003,Schwartz et al,2006),sediments (Samuelson et al,1992;Andersen and Sandaa,1994),and ground water (McKeon et al,1995). Though most of the bacteria showing resistance are not currently of medical concern,there is concern that non-pathogenic bacteria can serve as a platform for gene transfer to pathogenic organisms as a result of promiscuous exchange of genetic material among microbes (Kümmerer,2004;Bazquero et al,2008).

Methylated Arsenic

Arsenic (As),widely used in pesticide formulations (wood preservatives,insecticides,herbicides,fungicides,cotton desiccants,cattle and sheep dips),is one of the toxicants of greatest concern on the EPA National Priorities List and is ranked as the second most important chemical contaminant in Californias drinking water sources,according to the California Department of Health Services. In some estuaries and coastal waters,terrestrial runoff contaminated with As from pesticide use and other sources has led to hundredfold higher concentrations of inorganic As than the EPA recommendation for marine waters containing edible fish (Byrd,1990;EPA,1988;Andreae,1979;and Cutter and Cutter,1995).

Nanomaterials

A fundamental lack of data on the potential impacts of manufactured nanomaterials on natural ecosystems including soil and water resources currently exists. This situation is in contrast with what appears to be widespread adoption of nanotechnology as a part of the 21st Centurys new product flow. It is now reported that in 2006 more than $50 billion dollars of nano-enabled products were sold worldwide (Jusko,2007). A recent survey of 407 nanotechnology company executives conducted by the University of Massachusetts-Lowell showed 56% of the firms are expecting sales resulting from nano materials of $10 million or greater within three years (Hock et al,2007). Almost 97% of the respondents found it important for the government to address potential health affects and environmental risks associated with nanotechnology. Interestingly,these industrial concerns echo an earlier opinion expressed by citizens groups from around the world. A consumer survey (from 6,000 interviews) reported by the German Federal Institute for Risk Assessment show that clear definitions and standards as well as far more research into the potential problems of nanotechnology is needed,before the technology finds a wider use (BfR,2006).

Uniqueness of This Project

The proposed project is distinct from and complements 3 other multistate projects.

W45 focuses on identifying,predicting,and mitigating any adverse impacts of agricultural chemicals to human,animal,and ecosystem health. An additional goal of that project is to identify,develop,and validate trace residue analytical methods,immunological procedures,and biomarkers for agricultural chemicals. In contrast,the currently proposed project is directed less to biological responses to pesticides and pharmaceuticals and more toward predicting and managing the interactions of these chemicals in soil and water before adverse health impacts develop.

W1188 seeks to improve understanding of how physical properties and processes govern mass and energy transport in soils and how these processes mediate biogeochemical interactions at different scales. Although the environmental fate and transport of pesticides and pharmaceuticals are clearly linked to physical properties and processes,the emphasis of the presently proposed project is on chemical properties of the chemicals and on the chemical,mineralogical,and surface properties of potential solid-phase sorbents in soils and sediments.

W1170 evaluate the fate of nutrients,trace elements,and contaminants applied to soils with residual amendments such as biosolids. While some research associated with W1170 deals with organic chemicals,much of W1170's focus is on potentially toxic trace metals,nitrogen,and phosphorus that are land-applied with biosolids. In contrast,collaborators in the currently proposed project work entirely with the fate of organic chemicals,i.e.,pesticides that are applied in normal agricultural operations as well as with pharmaceuticals that may be dispersed to the environment subsequent to land applications of biosolids or animal manure.

Objectives

1. To identify and quantify fundamental chemical, physical, and biological processes relevant to pesticides and contaminants in agricultural ecosystems,
   
2. To evaluate existing transport models for predicting the fate and transport of pesticides and contaminants in agricultural ecosystems,
   
3. To provide information and outreach required for field-scale recommendations for the management of pesticides and contaminants in agricultural, suburban, x-urban and rural ecosystems.
   

Methods

Objective 1 Sorption and desorption of organic compounds by and from geomedia (soil,subsurface material,soil components,and organo-clays) will continue to be characterized by batch equilibration techniques,steady-state flow and interrupted-flow miscible displacement techniques,and by thermodynamic,kinetic,spectroscopic,and solvent-extraction techniques. These experiments are fundamental and common to most of the research activities that will be conducted in this project. Experiments will be conducted under different soil-to-water ratios from unsaturated to flooded conditions,with varying temperatures,residence times,and the presence or absence of soil amendments,surfactants,colloids,or co-solutes. In selected studies,model sorbents that include polymers,lignin,resins,and soil extracts will be employed to aid in identification of molecular-scale mechanisms. New models that describe sorption and desorption of organic compounds and that are commensurate with the complexity of soil-water systems must be developed. In the research planned by project collaborators,soil extraction and preservation techniques both long-term and short-term sorption kinetics and the formation of irreversibly bound residues will be studied after varying incubation periods,including use of soil materials contaminated and aged in the field and laboratory. Chromatographic,spectroscopic,and radiolabeled assay techniques will be used to monitor chemical concentrations and chemical alterations in the soil-water system. Soil organic matter will be characterized by 13C-NMR spectroscopy as well as by infrared and ultraviolet spectroscopy. An important collaborative effort in the project consists of communication among researchers about these techniques so that they can be implemented in ways that allow direct comparison among studies. Pesticides/metabolites Biotransformations of As by marine algae in near-coastal areas with known high concentrations of dissolved As will be investigated: (1) determining which abiotic factors (e.g.,oxidation state,pH,competing phosphate concentrations) influence As uptake and (2) determining As speciation (methylated forms,arsenosugars) in marine algae. Ulva lactuca,a green alga that thrives in estuarine environments due to its strong capacity for osmotic regulation will be used. Since Ulva lactuca is designated by the Institute of Reference Materials and Measurements as a certified reference material,biological standards will be available for use as internal controls. Pure cultures of Ulva lactuca will be obtained to conduct batch culture experiments. We expect to characterize the potential risks As may pose as it is transformed into various chemical forms and moves from algae to higher trophic levels. Herbicide Degradation Soil and BioChar will be thoroughly mixed. Each soil sample will be treated with 3 mL of an aqueous solution of herbicide. The soil moisture will be adjusted to -33 kPa. The soil will be mixed and incubated in the dark at 20C until analyzed at 0,3,7,11,and 21 d after herbicide treatment. At time zero and selected times samples will be removed and sequentially extracted using an accelerated solvent extraction (ASE) system using various solutions. Analysis of herbicides will be by GC/MS or LC/MS. Dissipation of the herbicides will be calculated from total extractable amount with time. Aging The research will use a sequential solvent extraction method with an ASE system to determine the sorption Kd values of the selected herbicides in freshly treated and aged soils. Soils with differing physical and chemical properties will be obtained. Soils will be treated with herbicides at variable rates from 0.05 to 5 ug g-1 and then incubated at constant temperature (25ºC). At time zero and selected times samples will be removed and sequentially extracted using the ASE. First extraction will be done with 0.01M CaCl2 and second with acetonitrile-water (90:10,v:v). Sorption coefficients (Kd) will be calculated as the ratio of organic solvent extractable and aqueous solvent extractable,and dissipation of the herbicides will be calculated from total extractable amount with time. Sequential extraction by ASE is an easy method to characterize sorption of aged residues in soils. Biochar sorption of pesticides Effects of BioChar addition to soil on the sorption and bioavailability of applied herbicides and fungicides,soil contaminants,and allelochemicals will be investigated. Soil contaminants include legacy pesticides,contaminants that accompany the addition of biosolids,and antibiotics/hormones that accompany animal manures. Allelochemicals are natural signaling chemicals among plant,microbe and animal species that are important in the health of many crop plants. A systematic investigation will be undertaken of the contribution of pi-pi electron donor-acceptor interactions of aromatic compounds to sorption from water to black carbon,fullerenes and carbon nanotubes. A related investigation will examine steric effects in sorption to black carbon (i.e.,size exclusion in micropores). Novel NMR acquisition and spectral editing techniques will be applied in combination with sorption experiments to gain information about the nature of the sorbed complex of organic compounds withBioChar. Sorption hysteresis Pesticide sorption and availability in BioChar amended soils will be investigated. Biochar can be formed by prylosis of residues to form syngas. The time and temperature of the reaction can influence the pH and other properties of the biochar. Adding different amounts of biochars produced by various processes differentially affects soil pH and sorption characteristics of pesticides to soil. Sorption/desorption characteristics and efficacy of preemergence herbicides will be evaluated in laboratory and greenhouse experiments. Pharmaceuticals and Personal Care Products There is concern about the environmental dispersion of pharmaceutical chemicals such as antibiotics and hormones in animal waste and biosolids as well as compounds derived from personal-care products. Laboratory batch and column studies will be conducted to characterize the fate and transport of veterinary antibiotics (VAs) in geomedia. More targeted studies will focus on the sorption of VAs to soils collected from vegetative buffer strips (VBS) in order to elucidate VBS potential for mitigating VA loss from agroecosystems. The influence of manure-derived dissolved organic matter (DOM) on veterinary antibiotic sorption and transport will also studied. Soil and sediment sample handling and preparation for analysis is an area requiring investigation. Project participants will examine selected methods for soil sample preservation and extraction of contaminants from soils. Transport processes in unsaturated soil environments differ from those in saturated environments,for some compounds. Project participants will conduct soil column transport experiments at less than saturated soil water conditions to elucidate the extent to which transport / sorption is affected by the degree of saturation. Samples will be collected and analyzed to quantify distribution of selected chemicals throughout the soil profile for soils irrigated with municipal effluent and used for agricultural and forest production. Additional studies will be conducted to assess the development of antibiotic resistance in natural populations of soil bacteria. Study sites have been established in a riparian area that has undergone long-term (15-year) recharge with reclaimed wastewater,and a turfgrass area irrigated with reclaimed water for over 10 years. Gram-positive microbial isolates from soils will be exposed to a range of antibiotics to determine relative resistance,and resistance profiles will be compared to bacterial isolates from soils irrigated with groundwater. Redox sensitive degradation of pharmaceutical compounds will be examined in wastewater recharge facilities where the impact of temperature on dissolved organic carbon (DOC) degradation and the resulting impact on redox zonation will be examined. Pharmaceutical residue degradation in winter versus summer months will be studied where the rate of degradation of DOC will be expected to influence the fate of pharmaceutical compounds. Sorption isotherms for soils,organic materials and other solids will be generated,classified,and relevant sorption coefficients (linear Kd,Freundlich Kf,organic carbon Koc,and clay mineral Kcm) calculated. Reversibility of sorption (desorption and hysteresis) will be determined by replacing the supernatant with sorbate-free solution,re-equilibrating and measuring changes in solution concentration. Desorption isotherms will be constructed and constants calculated. 14C-radiolabled compounds may be used to facilitate some measurements. Mixtures of two or more compounds will be equilibrated to determine competition for sorption sites in soils and sediments containing multiple organic and inorganic contaminants. Effect of nanomaterials in the environment The effects of nanomagnetite on pure cultures of bacteria as well as soil microorganisms will be investigated. Bacterial growth experiments will be conducted using batch cultures. Impact on soil microbial communities will be evaluated using phospholipids fatty acid analysis (Feng et al,2003) and PCR-DGGE (Tong et al,2007). Bioavalability of selected compounds Selected environmentally relevant xenobiotics will be used in this research. The primary focus is pesticides and PhACs. Studies will include low and high concentrations (representing nonpoint and point sources and various exposure levels). Parent compounds will be obtained from commercial,industrial,or government sources. Some intermediates,derivatives and degradation products which are not readily available may need to be synthesized. Nonionic surfactants including the synthetic nonionics,microbial biosurfactants,oligosaccharides,as well as beractant solution [a natural bovine lung extract containing phospholipids,neutral lipids,fatty acids and surfactant proteins with added colfosceril palmitate (dipalmitoylphosphatidylcholine,used in preparing liposomes;Miller,1995),palmitic acid and tripalmitin] will be used to simulate bioavailability from facilitated dissolution of contaminants in soil-water environments and mammalian digestive and respiratory systems. Various alcohols will be used as carrier solvents for spiking soils and as mild organic extractants in surrogate assays for bioavailability. Activated carbon may be used to control contaminant availability in some tests (Vasilyeva et al,2001). Experiments will be conducted in aqueous solutions,soils,sediments and livestock waste,contaminated waters and field soils,and simulated mammalian gastric and lung fluid matrices. Laboratory experiments will be conducted in batch and column bioreactors under ambient conditions or in an anaerobic glovebox (3-5% H2 in N2),as described by Elovitz and Weber (1999). In some experiments an Eh-pH potentiostat-controlled microcosm (Petrie et al,1998;Singh et al,1999) may be used for redox and pH control. Degradation and Transformation Soils,water and livestock waste containing the targeted pesticide(s) and PhAC(s) will be incubated under conditions simulating natural or managed environments. The formation,kinetics,intermediates,and breakdown products of nitrosamines and other secondary compounds from selected pesticides and PhACs will be evaluated under simulated environmental conditions. Anaerobic,aerobic or sequential conditions will be created by adjusting soil/sediment water and/or oxygen content. Nutrient status,buffer conditions and pH will be adjusted as desired. Contaminant loss and degradation will be determined in response to the imposed treatment condition(s) and incubation time. Decay functions will be fitted to the data to determine half-lives or disappearance times. These data will be correlated to soil physical,chemical and biological characteristics to model and predict contaminant fate. The ability of different vegetative species to enhance pharmaceutical degradation will be evaluated using greenhouse and/or growth chamber studies. These trials will help screen species for inclusion in vegetative buffer strips that can be implemented within or along the edges of fields to help mitigate loss of veterinary antibiotics from agroecosystems. Effect of biochar on pesticide degradation in soils will be determined including metolachlor and glyphosate using a procedure modified after Feng et al (2000). Contaminant Availability Acetonitrile or other suitable organic solvent(s) will be used to determine total extractable organic contaminant residues in contaminated soils,sediments,organic matter and other particulates. In addition to aqueous solutions,weak salt solutions (e.g.,3 mM CaCl2 used in previous research;Hundal et al,1997) and 90% isopropanol solution (which correlated well with removal of organic contaminants by biodegradation;Tabak et al,2003) will be used as chemical assays for readily available residues. A sequential extraction scheme similar to those employed by Hundal et al (1997) and Elovitz and Weber (1999) will be followed. Readily available contaminant concentrations will be determined by adding a suitable volume of mild extractant to the contaminated sediment,followed by vortex mixing and shaking for 18 h or a suitable period,and analyzing the supernatant. The remaining sediment will then be extracted with CH3CN to determine potentially available or total remaining residues. Molar HCl and NaOH (or KOH) solutions will be used to release entrapped residue and determine acid- or alkali-hydrolyzable covalent linkages (Hundal et al,1997;Elovitz and Weber,1999). In some tests,the compound of interest may be applied to soil/sediment in alcohol solution to simulate natural aging (and hysteresis) by increasing access to domains within the deformable organic structure (Bouchard,1998). Rhamnolipids and lipopolysaccharides (microbial biosurfactants) may be included in some experiments to estimate bioavailability in soil (or sediment)-water matrices. PhACs in Livestock Waste Laboratory batch and column reactors will be used to evaluate the degradation and availability of selected PhACs in livestock waste and soil receiving the waste. It is important to determine practices that minimize the release of antimicrobials and active breakdown products to the environment. Experimental variables include waste holding time (before land application),aeration,and pH. Protocols of Accinelli et al (2007) for degradation and sorption of antimicrobial agents will be followed with modifications as required. Availability will be determined through sorption and desorption measurements,using methods similar to Fernando et al (2005) for ammonium in swine waste. Objective 2 At the USDA-ARS Salinity Laboratory a two-dimensional numerical model to simulate the fate and transport of fumigants from the fumigated fields will be developed,tested and evaluated. The numerical simulation will simultaneously solve water,heat,and solute transport equations and include chemical transport in the vapor phase. Two volatilization boundary conditions will be explored to assess their accuracy in predicting the volatilization rates. One boundary condition will follow stagnant boundary layer theory and use no atmospheric information. The second boundary condition will couple soil and atmospheric processes and will be tested to determine if it provides a more accurate simulation of the instantaneous volatilization rates compared to a stagnant boundary layer condition. The HP-1 model developed at the USDA-ARS Salinity Laboratory couples the advection-dispersion-reaction equations to a geochemical dissolution component. The model is useful of the transport of redox-sensitive chemicals,metal-organics,and other components of interest. A process-based index model has been developed to assess vulnerability to contamination from pesticide leaching and runoff based on landscape and pesticide properties. The model is currently being applied to map landscape vulnerability to pesticide leaching,solution runoff,and particle adsorbed runoff in the four county Blue River watershed at the Nebraska-Kansas border. In the multi-state project,these models will be used to determine leaching and runoff risks for selected pharmaceuticals. Koc and half-life values of pharmaceuticals will be determined experimentally if this information is not available. Based on experimental results and model output,guidelines will be developed for the management of wastes containing pharmaceuticals. The Nebraska participant holds a partial extension appointment and is a member of the Heartland Region Pesticides Best Management team (activities also encompass agricultural pharmaceuticals),which provides a regional outlet and mechanisms for delivery of this information to agencies,pesticide and pharmaceutical practitioners,and the public. Objective 3 Use Life Cycle analysis (LCA) to assess the overall environmental effect of using antimicrobial compounds in swine facilities at different stages in the operation. The project will help Hawaii in pesticide registration activities. Hawaiis sole reliance on ground water entrusts the state Department of Agriculture to take appropriate steps to prevent/reduce contamination of underlying soil and ground water in agricultural area. Field and laboratory evaluation of leachability of new chemicals entering Hawaii will benefit from this project. Research conducted by committee members provides information needed to develop management strategies that can reduce soil and water contamination from pesticides,pharmaceuticals,and other toxic organic compounds. This information includes (1) identification of key parameters controlling the environmental fate of a particular contaminant or contaminant class,(2) expanding the environmental fate information database,(3) quantifying fate relative to various environmental parameters,(4) development of realistic inputs for computer simulation models,and (5) development of algorithms to characterize specific group of processes that can then be incorporated into larger scale models. Research efforts of collaborators on this proposal will support process models that describe the retention,transformations,and transport of pesticides and pharmaceuticals under a range of soil,climatic,and environmental conditions,landscape settings,and soil management practices. Included in this renewal proposal are individuals that hold partial or complete extension appointments. They will be instrumental in identifying ways to engage critical stakeholders in the research process so that research results of the committee are used and valued. Dr. Hirschi,for example,is the Water Quality Program Coordinator for University of Illinois Extension,and he serves on the Great Lakes Regional Water Quality Leadership team that implements the USDA-CSREES Section 406 Regional WQ Coordination grant. In that role,he is in an ideal position to help us target dissemination of our work to extension personnel and water-quality professional in other disciplines. Dr. Watson and Dr. Hirschi will play active roles in technology transfer as well as encourage and facilitate technology transfer by the rest of the committee. The collaborators will work towards enhancing communication and distribution to various users group throughout the next 5-year project period in several planned outputs. Execution of field demonstration sites using the Urban Extension network in each collaborating state will heighten the visibility of the outcomes,engage people from broader cross sections of the community,engage elected officials from those areas,and gain notoriety through more popular media avenues that might otherwise be unavailable to the scientific community.

Measurement of Progress and Results

Outputs

• Sponsor a symposium on fate of pesticides and pharmaceuticals in agricultural ecosystems at the annual meeting of an appropriate professional society.
• Submit joint research proposals dealing with pesticides, nanomaterials and pharmaceuticals in agricultural ecosystems to national funding agencies.
• Develop technical documents for best management practices for pesticides, nanomaterials and pharmaceuticals in agricultural ecosystems.
• Publish peer-reviewed journal articles and review articles.
• Participate in extension publications and field days dealing with pesticides, nanomaterials and pharmaceuticals in agricultural ecosystems.
• "Members of the multistate research project commit to the following outputs during the five-year course of the project. Institutions committed to collaborative leadership for each output are indicated in parentheses. "Sponsor a symposium on fate of pesticides and pharmaceuticals in agricultural ecosystems at the annual meeting of an appropriate professional society. "Submit joint research proposals dealing with pesticides, nanomaterials and pharmaceuticals in agricultural ecosystems to national funding agencies. "Develop technical documents for best management practices for pesticides, nanomaterials and pharmaceuticals in agricultural ecosystems. "Publish peer-reviewed journal articles and review articles. "Participate in extension publications and field days dealing with pesticides, nanomaterials and pharmaceuticals in agricultural ecosystems. "Develop plan for at least one field demonstration outreach site in each urban extension partner state.

Outcomes or Projected Impacts

• "A better understanding of environmental impacts of pesticides, pharmaceuticals, hormones, and nanomatreials.
• "Demonstration field models established in metro areas in each of the urban extension partner states through the Urban Extension network to elevate profile of the scientific work, test science in real life/time environments, provide opportunities for popular support of the findings and methods.
• "An assessment of the effects of biochar on the biological availability of agriculturally important chemicals will provide critically needed information regarding the suitability of biochar for widescale use as a soil amendment in agriculture.
• "This study will define the role of pi-pi electron donor-acceptor interactions and steric effects in sorption to black carbon, an important component of agricultural soils.
• "Application of advanced NMR techniques will provide a wealth of information about the sorbed complex including structural changes of SOM taking place during sorption; preferential sites of sorption in SOM; and the relationship between fused ring content and size and sorption coefficient.

Milestones

(2010): Sponsor a symposium on fate of pesticides and pharmaceuticals in agricultural ecosystems at the annual meeting of an appropriate professional society

(2011): Submit joint research proposals dealing with pesticides or agricultural pharmaceuticals to national funding agencies

(2012): Develop joint protocol for extraction and analysis of trace contaminants

(2013): Develop technical documents for methodological protocols and best management practices for pesticides and agricultural pharmaceuticals

(2014): Publish a special journal issue, book chapter, or a regional research bulletin to summarize research with pesticides and agricultural pharmaceuticals. Establish at least 4 demonstration sites that can be integrated into the project for data collection, public and academic demonstration, utilization as student engagement opportunities, and provide opportunities for sharing physical characteristics of various interventions.

Projected Participation

View Appendix E: Participation

Outreach Plan

The results of collaborative projects described above will be made available to intended users in several ways:

Peer-reviewed journal articles and review articles are published in the scientific literature and available by subscription, at libraries, or on-line.

Participants in the symposium on the fate of pesticides and pharmaceuticals in agricultural ecosystems will hear research results at the symposium and will have opportunity to interact with project members who are presenting results.

Extension specialists in soil and water quality will participate in the meeting on agricultural pharmaceuticals and will learn about the group's activities by presentations and informal interactions at the meeting.

Technical reports concerning methodological protocols and best management practices for pesticides and pharmaceuticals in agricultural ecosystems will be posted on the project's web site at NIMSS.

Extension publications will be issued by participating experiment stations.

Members will present the latest information about pesticides and agricultural pharmaceuticals to the general public at agricultural field days in the participating states.

Organization/Governance

The project will be coordinated among the collaborating scientists by
(a) five meetings of the participants organized on an annual basis,
(b) e-mail and conference calls, and
(c) the project's organizational structure: a chair and secretary elected at annual meetings by the membership for two-year terms beginning 2010.

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Attachments

Land Grant Participating States/Institutions

AL, CA, CO, CT, DE, HI, IL, IN, KY, MI, MN, MO, MS, NE, NJ, NM, PA, SD, TN, TX, VA, WI

Non Land Grant Participating States/Institutions

Johns Hopkins University, Northeast Region - USDA-ARS, Pasture Systems and Watershed Management Research Unit, University of Illinois at Urbana-Champaign, USDA-ARS/Arizona, USDA/ARS-California