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United States Department of Agriculture

Agricultural Research Service

Research Project: METABOLIC VARIABLES AFFECTING THE EFFICACY, SAFETY, AND FATE OF AGRICULTURAL CHEMICALS

Location: Animal Metabolism-Agricultural Chemicals Research

2011 Annual Report


1a.Objectives (from AD-416)
Objective 1: Determine metabolic variables (rates of absorption, tissue and microbial biotransformation, excretion) that positively or negatively influence the practical use of novel pre-harvest food safety chemicals in food animals. Objective 2: Determine the fate of endogenous animal hormones, novel pre-harvest food safety compounds, and antibiotics in animal wastes, including their transport through soil and water, and develop intervention strategies that reduce their environmental impact. Objective 3: Develop sensitive and accurate analytical tools to rapidly detect and quantify agriculturally important chemicals studied under objectives 1 and 2.


1b.Approach (from AD-416)
The broad objective of this proposal is to determine the fate of chemicals in food animals and in the environment (excreta, soil, water) after elimination from food animals. We will study endogenously produced steroid hormones, novel developmental oxyanions, novel developmental nitro-compounds, and antibiotics. Endogenous steroid hormones (estrogens) are highly potent endocrine-disrupting compounds that may concentrate in intensive food-animal production settings. Novel developmental compounds show promise for food-safety applications in ruminant, non-ruminant, and avian food animals. Specifically we plan to.
1)determine the metabolic variables (i.e., absorption, tissue and microbial biotransformation, rates of excretion) that positively or negatively influence the food safety (i.e., tissue residues) of developmental oxyanions such as chlorate salts and novel nitro-compounds such as 2-nitropropanol in food animals;.
2)determine the fate of steroid hormones, antibiotics, and developmental compounds in manure management systems of animals and in soils with the goal of gaining an understanding of the impact that residues of such chemicals may have in intensive food animal production settings; and.
3)we will develop analytical tools for the accurate measurement and(or) identification of these analytes or their metabolites.


3.Progress Report
This is the final report of the 5 year project 5442-32000-012-00D, which was terminated in 2011 and replaced with project 5442-32000-014-00D. Substantial progress was made during the life of the project. For example, the metabolic fate and tissue residues of chlorate salts in swine, broilers, and lactating sheep were determined under anticipated commercial use conditions. A major finding was that a presumed metabolite of toxicological concern, chlorite, is not present in animal wastes or in tissues used for food and that tissue chlorate residues should fall well below thresholds for food safety concern being considered by the US FDA CVM. The major product of chlorate metabolism in live animals and in animal waste systems is chloride, a nutrient. Larger than expected levels of estradiol were detected in well water from fields receiving swine manure, but surface waters collected from fields amended with dairy manure contained estrogen levels below proposed regulatory action limits. It was hypothesized that soil reservoirs of estrogen are associated with small particles or as water soluble metabolites. Subsequent studies demonstrated that soil particles enhance estradiol persistence and that water soluble metabolites of estrogen have significant capacity for water transport and for conversion to parent estradiol. Estradiol is detected more frequently in soil layers nearer to the water table than in the upper, more highly organic layers, providing evidence of how estradiol contamination of groundwater can occur. Laboratory studies of composting, anaerobic and aerobic digesters, and chemical treatments and on-farm studies with constructed wetlands suggest that application of these technologies in animal waste process streams could reduce estrogen releases into the environment. Analytical methods were developed for chlorate salts in diverse matrices including serum, urine, feces, intestinal fluids, and milk. For chlorate analyses requiring high sensitivity, a liquid chromatography-mass spectrometric method was developed utilizing an 18-oxygen stable isotope internal standard. Immunologically based assays for sulfonamides were used to analyze effluents from wastewater treatment plants and swine rearing facilities and a multi-residue method was developed to simultaneously analyze structurally related sulfonamides in soil and water. The methods could be used to assist in monitoring the environmental fate of sulfonamides. Immunochemical methods to detect the beta-adrenergic agent zilpaterol were generated and validated using animal systems and these reagents were made commercially available through license agreements. A liquid chromatography-mass spectrometry method was also developed and validated for the measurement of exquisitely small concentrations of estradiol in surface and groundwater. This assay is being used in several studies investigating the fate of and remediation of estradiol in agricultural settings. The limitation of commercially available estrogen analysis kits for application to environmental estrogen analysis was also evaluated and compared to mass-spectral and cell-based analyses.


4.Accomplishments
1. Safe residues after vegetable fumigation to eliminate pathogens. Chlorine dioxide gas fumigation of fruits, vegetables, and melons effectively kills pathogen contaminants and increase produce shelf-life. The technology has not been used commercially because any residues remaining on fruits, vegetables, or melons after chlorine dioxide treatment have not been quantified or characterized. ARS scientists in Fargo, ND, in collaboration with Purdue University determined that essentially all of the residues remaining on chlorine dioxide treated vegetables are non-toxic, natural products. The data have been submitted to the US-Environmental Protection Agency in support of a product registration for the use of chlorine dioxide gas for decreasing pathogen content and increasing shelf-life of vegetables. Decreasing pathogen loads on fruits and vegetables, without increasing risks of chemical residues, increases the safety of food for US consumers.


Review Publications
Shappell, N.W., Hyndman, K., Bartell, S.E., Schoenfuss, H. 2010. Comparative biological effects and potency of 17a- and 17ß-estradiol in fathead minnows. Aquatic Toxicology. 100:1-8. DOI:10.1016/j.aquatox.2010.07.005.

Schuh, M.C., Casey, F.X., Hakk, H., Desutter, T.M., Richards, K. G., Khan, E., Odour, P. 2011. An on-farm survey of spatial and temporal stratifications of 17ß-estradiol concentrations. Chemosphere. 82:1683-1689.

Derby, N.E., Hakk, H., Casey, F.X.M., Desutter, T.M. 2011. Effects of composting swine manure on nutrients and estrogens. Soil Science. 176(2):91-98.

Zitnick, K.K., Shappell, N.W., Hakk, H., DeSutter, T.M., Khan, E., Casey, F.X.M. 2011. Effects of liquid swine manure on dissipation of 17ß-estradiol in soil. Journal of Hazardous Materials. 186:1111-1117.

Smith, D.J., Taylor, J.B. 2011. Chlorate analysis in matrices of animal origin. Journal of Agricultural and Food Chemistry. 59:1598-1606.

Shrestha, S.L., Bai, X., Smith, D.J., Hakk, H., Casey, F.X.M., Larsen, G.L., Padmanabhan, G. 2011. Synthesis and characterization of radiolabeled 17ß-estradiol conjugates. Journal of Labelled Compounds and Radiopharmaceuticals. Vol. 54(5):267-271.

Shelver, W.L. 2011. Generation of antibody and development of an enzyme-linked immunosorbant assay for the feed additive roxarsone. Food and Agricultural Immunology. 22(2):171-184.

Fan, Z., Casey, F.X., Hakk, H., Larsen, G.L., Khan, E. 2011. Sorption, fate, and mobility of sulfonamides in soils. Water, Air, and Soil Pollution. 218(1):49-61.

Shelver, W.L., Smith, D.J. 2011. Immunochemical-based zilpaterol measurement and validation in urine and tissues. Food and Agricultural Immunology. 22(3):247-258.

Hakk, H., Sikora, L. 2011. Dissipation of 17B-estradiol in composted poultry litter. Journal of Environmental Quality. 40:1560-1566.

Schuh, M.C., Casey, F.X.M., Hakk, H., DeSutter, T.M., Richards, K.G., Khan, E., Odour, P.G. 2011. Effects of field-manure applications on stratified 17B-estradiol concentrations. Journal of Hazardous Materials. 192:748-752.

Wang, J., Li, H., Shelver, W.L., Wang, Z., Li, Q.X., Li, J., Xu, T. 2011. Development of a monoclonal antibody-based, congener-specific and solvent-tolerable direct enzyme-linked immunosorbgent assay for the detection of 2,2',4,4'-tetrabromodiphenyl ether in environmental samples. Analytical and Bioanalytical Chemistry. 401:2249-2258.

Last Modified: 7/28/2014
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