Source: AGRICULTURAL RESEARCH SERVICE submitted to
DIOXINS AND OTHER ENVIRONMENTAL CONTAMINANTS IN FOOD
Sponsoring Institution
Agricultural Research Service/USDA
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0410310
Grant No.
(N/A)
Project No.
5442-32000-011-00D
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Feb 8, 2006
Project End Date
Feb 7, 2011
Grant Year
(N/A)
Project Director
HUWE J K
Recipient Organization
AGRICULTURAL RESEARCH SERVICE
(N/A)
FARGO,ND 58102-2765
Performing Department
(N/A)
Non Technical Summary
(N/A)
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
0%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
7123260200010%
7123310200060%
7123510200030%
Goals / Objectives
In order to reduce exposure to dioxins and other environmental contaminants from the food supply, four objectives have been outlined for this research project. 1) Develop inexpensive, rapid, sensitive, assays or improved diagnostic tools to screen samples for dioxins, pesticides, chemical residues, and other environmental contaminants. 2) Investigate sources which contribute to levels of these contaminants in food animals and identify intervention strategies that may reduce the levels. 3) Investigate the uptake, metabolism, distribution, excretion, and fate after excretion of environmental contaminants in animal systems. 4) Update data on levels of dioxins and related compounds in the domestic food supply to provide Food Safety agencies with an adequate profile of the situation and confirm the safety, security, and competitiveness of U.S. foods and food supply.
Project Methods
New tools, such as antibody-based or receptor-based assays, that make analyses cheaper and less time consuming, will be developed to facilitate monitoring of targeted chemicals in the food supply. Sources that contribute to livestock exposure throughout the production process will be investigated and cataloged. Once identified these sources may be eliminated or avoided in farming practices in order to prevent or minimize entrance into the food chain. Basic research to determine pharmacokinetic parameters for these pollutants in laboratory and farm animals will be investigated through animal feeding studies. These data will be used to calculate withdrawal intervals, evaluate source attribution, and elucidate strategies to decrease contaminant levels in food animals. In addition to pharmacokinetic parameters, studies on the fate of a chemical dosed to an animal can provide knowledge of basic biological mechanisms that may be exploited to reduce uptake, increase excretion, or enhance degradation of these contaminants, thereby, lowering levels found in animal food products and the environment. Surveys of the general food supply (especially meat and poultry) will be conducted to provide typical levels of these compounds in U.S. foods.

Progress 02/08/06 to 02/07/11

Outputs
Progress Report Objectives (from AD-416) In order to reduce exposure to dioxins and other environmental contaminants from the food supply, four objectives have been outlined for this research project. 1) Develop inexpensive, rapid, sensitive, assays or improved diagnostic tools to screen samples for dioxins, pesticides, chemical residues, and other environmental contaminants. 2) Investigate sources which contribute to levels of these contaminants in food animals and identify intervention strategies that may reduce the levels. 3) Investigate the uptake, metabolism, distribution, excretion, and fate after excretion of environmental contaminants in animal systems. 4) Update data on levels of dioxins and related compounds in the domestic food supply to provide Food Safety agencies with an adequate profile of the situation and confirm the safety, security, and competitiveness of U. S. foods and food supply. Approach (from AD-416) New tools, such as antibody-based or receptor-based assays, that make analyses cheaper and less time consuming, will be developed to facilitate monitoring of targeted chemicals in the food supply. Sources that contribute to livestock exposure throughout the production process will be investigated and cataloged. Once identified these sources may be eliminated or avoided in farming practices in order to prevent or minimize entrance into the food chain. Basic research to determine pharmacokinetic parameters for these pollutants in laboratory and farm animals will be investigated through animal feeding studies. These data will be used to calculate withdrawal intervals, evaluate source attribution, and elucidate strategies to decrease contaminant levels in food animals. In addition to pharmacokinetic parameters, studies on the fate of a chemical dosed to an animal can provide knowledge of basic biological mechanisms that may be exploited to reduce uptake, increase excretion, or enhance degradation of these contaminants, thereby, lowering levels found in animal food products and the environment. Surveys of the general food supply (especially meat and poultry) will be conducted to provide typical levels of these compounds in U.S. foods. This is the final report of project 5442-32000-011-00D, which expired in 2011 and was replaced with project 5442-32000-013-00D under which continuing milestones and accomplishments are reported. Over the five years of the project, significant progress was made on all four objectives. 1. Rapid assays for environmental contaminants were developed and commercialized based on novel antibodies generated at our laboratory. These antibody-based assays are sensitive, specific, rapid, and more cost- effective than current analytical methods and provide scientists and regulators a high-throughput, low cost way to monitor these pollutants in soil, water, and food. Contaminants targeted by the assays include several persistent, toxic brominated flame retardants, the antimicrobial agent Triclosan, a biological toxin in drinking water (geosmin), and the industrial contaminants perfluorooctanoic acid and melamine. Two of the assays have been commercialized through technology transfer agreements. 2. In studies to investigate sources of persistent pollutants to the food supply or intervention strategies, we showed that composting feedlot waste or utilizing natural soil microbes may be effective ways to destroy dioxins and other persistent pollutants and interrupt their recycling in the environment. We partnered with other researchers to estimate the emission of dioxins to the environment from certain agricultural burning practices and to show that contaminants present in indoor dust can be as important a source of exposure as contaminants in food. Results from these studies provide knowledge to scientists and regulators about practices that can help reduce pollutants in the environment or that are potential contributors. 3. Pharmacokinetic studies were conducted on numerous persistent pollutants to determine their uptake, tissue distribution, elimination, and fate after elimination both in laboratory and food-producing animals. The studies have shown that dioxins, dioxin-like compounds, and most polybrominated diphenyl ethers (a class of toxic flame retardants) are readily taken up by animals, stored in tissue fats, and not released. This means the unreasonably long withdrawal times would be needed to remove these residues from food animal tissues; however, trimming fat and consuming low-fat meats are a practical and simple way to reduce exposure to these contaminants. Conversely, studies with two other flame retardants (deca-BDE and gamma-hexabromocyclododecane) showed that these chemicals do not build up in animal tissues and are rapidly excreted; however, each can convert to a compound that is more persistent. Data from the pharmacokinetic studies are used to develop residue depletion models and to assess the risk of these contaminants to the food supply and the environment. 4. Surveys of domestically-raised meat and poultry and domestically- marketed catfish for residues of dioxins and dioxin-like compounds were conducted together with the Food Safety and Inspection Service. From 2007- 2010, 510 meat and poultry samples and 202 catfish samples were analyzed by state-of-the-art instrumental methods for more than 35 chemical pollutants. Accomplishments 01 A common nonstick chemical in consumer products does not accumulate in cattle. Perfluorooctanoic acid (PFOA) is a "nonstick" compound used in many industrial, commercial, and consumer products. Due to its extensive use, PFOA is widely found in humans, wildlife, and the environment. Catt are exposed to PFOA while grazing in contaminated areas, but the extent which it accumulates in their meat is not known. ARS researchers at Farg ND, in collaboration with the USDA Food Safety and Inspection Service, investigated to what degree this nonstick chemical concentrates in the edible tissues of beef cattle and whether this may be a concern for huma exposure. Using chemical tracking techniques, they determined that PFOA was quickly excreted by cattle in their urine, and no detectable amounts were left in the animal tissues. This study showed that PFOA is not like to accumulate in beef and that consumption of beef should not be a significant source of exposure for consumers.

Impacts
(N/A)

Publications

  • Holt, P.S., Davies, R.H., Dewulf, J., Gast, R.K., Huwe, J.K., Jones, D.R., Waltman, D., Willian, K.R. 2010. The Impact of Different Housing Systems on Egg Safety and Quality. Poultry Science. 90:251-262.
  • Huwe, J.K., West, M.S. 2011. Polybrominated diphenyl ethers in U.S. meat and poultry from two statistically designed surveys showing trends and levels from 2002 to 2008. Journal of Agricultural Food & Chemistry. 59(10) :5428-5434.
  • Szabo, D.T., Diliberto, J.J., Hakk, H., Huwe, J.K., Birnbaum, L.S. 2011. Toxicokinetics of the flame retardant hexabromocyclododecane alpha: effect of dose, timing, route, repeated exposure and metabolism. Toxicological Sciences. 121(2):234-244.


Progress 10/01/09 to 09/30/10

Outputs
Progress Report Objectives (from AD-416) In order to reduce exposure to dioxins and other environmental contaminants from the food supply, four objectives have been outlined for this research project. 1) Develop inexpensive, rapid, sensitive, assays or improved diagnostic tools to screen samples for dioxins, pesticides, chemical residues, and other environmental contaminants. 2) Investigate sources which contribute to levels of these contaminants in food animals and identify intervention strategies that may reduce the levels. 3) Investigate the uptake, metabolism, distribution, excretion, and fate after excretion of environmental contaminants in animal systems. 4) Update data on levels of dioxins and related compounds in the domestic food supply to provide Food Safety agencies with an adequate profile of the situation and confirm the safety, security, and competitiveness of U. S. foods and food supply. Approach (from AD-416) New tools, such as antibody-based or receptor-based assays, that make analyses cheaper and less time consuming, will be developed to facilitate monitoring of targeted chemicals in the food supply. Sources that contribute to livestock exposure throughout the production process will be investigated and cataloged. Once identified these sources may be eliminated or avoided in farming practices in order to prevent or minimize entrance into the food chain. Basic research to determine pharmacokinetic parameters for these pollutants in laboratory and farm animals will be investigated through animal feeding studies. These data will be used to calculate withdrawal intervals, evaluate source attribution, and elucidate strategies to decrease contaminant levels in food animals. In addition to pharmacokinetic parameters, studies on the fate of a chemical dosed to an animal can provide knowledge of basic biological mechanisms that may be exploited to reduce uptake, increase excretion, or enhance degradation of these contaminants, thereby, lowering levels found in animal food products and the environment. Surveys of the general food supply (especially meat and poultry) will be conducted to provide typical levels of these compounds in U.S. foods. We synthesized and tested two antigens designed as mimics for melamine to determine whether commercially available antibodies developed for triazine pesticides had the ability to bind melamine-like analytes. The results showed that commercially available antibodies did not produce a strong response towards the melamine antigens, meaning new antibodies would need to be produced for a rapid antibody-based assay specific to melamine. In collaboration with the U. Hawaii, Encore, Inc., Abraxis LLC, and China Agricultural University, we used an enzyme immunoassay to measure polybrominated diphenyl ether (PBDE) levels in Hawaiian fish. Our results from the rapid immunoassay were verified by a traditional instrumental method (GC-MS) and demonstrated the suitability of this immunoassay for high throughput screening of PBDEs in fish. Pharmacokinetic studies with two radiolabeled stereoisomers of hexabromocyclododecane (HBCD) in mice were carried out in collaborative work with the US EPA, RTP, NC. Our laboratory conducted the isolation and identification of metabolites for this work and developed LC-MS-MS analytical methods for complete determination of stereo- and enantio- isomers. As part of our investigation into feeds and feed components as sources of dioxins to beef cattle, we have collected 37 beef adipose samples and 92 corresponding feed ingredients from three collaborators (NDSU, Carrington, ND; Northern Ag. Research Center, Havre, MT; and ARS, Clay Center, NE). This past year, all 37 adipose samples were analyzed for dioxins, furans, and dioxin-like polychlorinated biphenyls (PCBs). In collaborative work with researchers at the ARS laboratory in Sidney, MT, we investigated whether bacteria found in soils containing elevated dioxin or dibenzofurans concentrations can utilize dioxins or dibenzofurans as an energy source and thus be good candidates for bio- remediation. After our collaborators isolated and characterized dominant bacteria from the contaminated sites and performed initial energy source screening, our laboratory further tested their growth ability using dibenzofuran as a sole carbon source in different time periods. We then amended the successful isolates into highly contaminated soils and determined their ability to reduce dioxin/furan concentrations in the soils. Results from this first set of experiments were inconclusive. A survey of dioxins and other environmental contaminants in domestically- marketed catfish was started in collaboration with the USDA FSIS. Catfish samples (203) have been received from FSIS, and 40 of them have been analyzed by our laboratory for 17 polychlorinated dioxins/furans, 18 PCBs, and 16 PBDEs. When completed, this survey will provide an up-to- date assessment of the level of these environmental contaminants in U.S. catfish. In collaboration with the Maine Band of Maliseet Indians, we measured the levels of dioxins and dioxin-like compounds in 36 locally-grown meat products collected by the tribe. The results will be evaluated and compared to nationally-collected data to determine whether levels of dioxins are different in these tribal foods compared to other domestic meat and poultry. Significant Activities that Support Special Target Populations A Trust Fund Agreement was established with the Houlton Band of Maliseet Indians to determine the levels of dioxins and dioxin-like compounds in locally-grown meat products typically consumed by this special population in Maine. Accomplishments 01 Pharmacokinetics of a newly listed persistent organic pollutant characterized. Hexabromocyclododecanes (HBCDs) are high production volum chemical mixtures which have recently been named persistent organic pollutants due to their toxicity and bioaccumulation in the food chain; yet little is known about the fate of HBCDs in animal systems. ARS researchers at Fargo, ND, together with scientist at the US EPA in Research Triangle Park, NC, have studied the most common form of HBCD (gamma-HBCD) in mice and found that, although it is readily absorbed fro the diet, it is rapidly excreted in the urine and feces with a half-life less than 4 days. In the mice, a small percent of the gamma-HBCD was converted into alpha-HBCD, which may be the more toxicologically importa form of HBCD. Increased knowledge of the fate of individual HBCDs in mammalian systems will help to characterize the risk of this persistent organic pollutant class in the food chain. 02 Polychlorinated biphenyls (PCBs) and organochlorine pesticides assessed Alaskan seals. Alaskan fur seal populations are declining, and environmental contaminants are one suspected cause. An ARS researcher fr Fargo, ND, has partnered with researchers at the University of Hawaii an the University of Alaska to measure and assess the toxic potential of 14 polychlorinated biphenyls (PCBs) and 12 organochlorine pesticides in fur seals from St. Paul Island in the Northern Pacific Ocean near Alaska. Th study examined the levels of the congeners in tissues with respect to various mode of action and gained a better perspective on the importance of congener-specific analysis in understanding the potential causes of toxicity. The results showed that several PCB levels presented in fur se tissues could affect thyroid function. The application of toxicity grouping schemes may be of interest to researchers studying seal and oth animal populations, or to those who consume seal.

Impacts
(N/A)

Publications

  • Huwe, J.K., Pagan-Rodriguez, D., Abdelmajid, N., Clinch, N., Gordon, D., Holterman, J., Zaki, E., Lorentzsen, M.K., Dearfield, K. 2009. Survey of Polychlorinated Dibenzo-p-dioxins, Polychlorinated Dibenzofurans and Co- planar Polychlorinated Biphenyls in U.S. Meat and Poultry, 2007-2008: Effect of New Toxic Equivalency Factors on Toxic Equivalency Levels, Patterns, and Temporal Trends. Journal of Agriculture and Food Chemistry. 57:11194-11200. DOI:10.1021/jf902251t.
  • Hakk, H., Diliberto, J.J., Birnbaum, L.S. 2009. The Effect of Dose on 2,3, 7,8-TCDD Tissue Distribution, Metabolism and Elimination in CYP1A2 (-/-) Knockout and C57BL/6N Parental Strains of Mice. Journal of Toxicology and Applied Pharmacology. 241:119-126. DOI:10.1016/j.taap.2009.08.009.
  • Lorber, M., Patterson, D.G., Huwe, J.K., Kahn, H. 2009. Evaluation of Background Exposures of Americans to Dioxin-Like Compounds in the 1990's and the 2000's. Chemosphere. 77:640-651. DOI:10.1016/j.chemosphere.2009.08. 016.
  • Wang, D., Shelver, W.L., Atkinson, S., Mellish, J., Li, Q.X. 2010. Tissue Distribution of Polychlorinated Biphenyls and Organochlorine Pesticides and Potential Toxicity to Alaskan Northern Fur Seals Assessed Using PCBs Congener Specific Mode of Action Schemes. Archives of Environmental Contamination and Toxicology. 58:478-488. DOI:10.1007/s00244-009-9396-6.
  • Szabo, D.T., Diliberto, J.J., Hakk, H., Huwe, J.K., Birnbaum, L.S. 2010. Toxicokinetics of the flame retardant hexabromocyclododecane gamma: effect of dose, timing, route, repeated exposure and metabolism. Toxicological Sciences. 117:282-293. DOI:10:1093/toxsci/kfq183.
  • Kopf, P.G., Scott, J.A., Agbor, L.N., Boberg, J.R., Elased, K.M., Huwe, J. K., Walker, M.K. 2010. Cytochrome P4501A1 is required for vascular dysfunction and hypertension induced by 2,3,7,8-tetrachlorodibenzo-p- dioxin. Toxicological Sciences. 117:537-546. DOI:10.1093/toxsci/kfq218.
  • Hakk, H., Huwe, J.K., Murphy, K., Rutherford, D. 2010. Metabolism of 2,2', 4,4' Tetrabromodiphenyl (BDE 47) in Chickens. Journal of Agricultural and Food Chemistry. 58:8757-8762. DOI:10.1021/jf1012924.
  • Dunn, R.L., Huwe, J.K., Carey, G.B. 2010. Biomonitoring breast milk polybrominated diphenyl ethers as a function of environment, dietary intake, and demographics in New Hampshire. Chemosphere. 80:1175-1182. DOI:10.1016/j.chemosphere.2010.06.017.


Progress 10/01/08 to 09/30/09

Outputs
Progress Report Objectives (from AD-416) In order to reduce exposure to dioxins and other environmental contaminants from the food supply, four objectives have been outlined for this research project. 1) Develop inexpensive, rapid, sensitive, assays or improved diagnostic tools to screen samples for dioxins, pesticides, chemical residues, and other environmental contaminants. 2) Investigate sources which contribute to levels of these contaminants in food animals and identify intervention strategies that may reduce the levels. 3) Investigate the uptake, metabolism, distribution, excretion, and fate after excretion of environmental contaminants in animal systems. 4) Update data on levels of dioxins and related compounds in the domestic food supply to provide Food Safety agencies with an adequate profile of the situation and confirm the safety, security, and competitiveness of U. S. foods and food supply. Approach (from AD-416) New tools, such as antibody-based or receptor-based assays, that make analyses cheaper and less time consuming, will be developed to facilitate monitoring of targeted chemicals in the food supply. Sources that contribute to livestock exposure throughout the production process will be investigated and cataloged. Once identified these sources may be eliminated or avoided in farming practices in order to prevent or minimize entrance into the food chain. Basic research to determine pharmacokinetic parameters for these pollutants in laboratory and farm animals will be investigated through animal feeding studies. These data will be used to calculate withdrawal intervals, evaluate source attribution, and elucidate strategies to decrease contaminant levels in food animals. In addition to pharmacokinetic parameters, studies on the fate of a chemical dosed to an animal can provide knowledge of basic biological mechanisms that may be exploited to reduce uptake, increase excretion, or enhance degradation of these contaminants, thereby, lowering levels found in animal food products and the environment. Surveys of the general food supply (especially meat and poultry) will be conducted to provide typical levels of these compounds in U.S. foods. Significant Activities that Support Special Target Populations A magnetic particle enzyme immunoassay was evaluated to measure the biocide triclosan and its metabolite methyl-triclosan in wastewater, river water, and drinking water samples. Positive samples were confirmed by solid phase extraction followed by gas chromatography mass spectrometry. The percentage of triclosan removed by different waste water treatment plants was also evaluated and showed that the best removal rates were obtained by plants equipped with membrane bioreactors. Results showed the magnetic particle-based immunoassay was a feasible approach to screen for triclosan and methyl-triclosan in these types of water samples. Radiolabeled-hexabromocyclododecane (HBCD) and highly pure alpha- and gamma-HBCD diastereomers (an emerging class of flame retardant) were synthesized at our laboratory for use in pharmacokinetic and toxicokinetic studies in rodents done in collaboration with the US EPA, RTP, NC. Five collaborators from different areas of the U.S. were recruited to participate in an investigation of dioxins in feed sources of beef cattle. A protocol for collection of feed components and beef fat samples was written and distributed. Samples from one location have been received and analysis for dioxins and other dioxin-like compounds has begun. Samples from two USDA statistical surveys of dioxins in domestic meat and poultry conducted in 2002 and 2008 were analyzed for 16 common polybrominated diphenyl ethers (PBDEs) by high resolution gas chromatography/high resolution mass spectrometry (HRGC-HRMS). This information will provide the best estimates of PBDE residues in U.S. meat and poultry to date, and a comparison of the data from the two surveys should provide an indication of temporal trends of these contaminants. Our laboratory analyzed dosing pills and mouse liver samples for tetrachlorodibenzo-p-dioxin (TCDD) in support of research being conducted at the University of New Mexico on the toxicity of TCDD and its role in cardiovascular disease. Our laboratory analyzed several mouse adipose tissue samples for polybrominated diphenyl ethers (PBDEs) in support of research being conducted at the University of New Hampshire on the possible role of PBDEs in obesity. In collaborative work with researchers at the ARS laboratory in Sidney, MT, we have begun to evaluate if bacteria from soils with elevated dioxin/furan concentrations utilize dioxins as an energy source and thus may be good candidates for bio-remediation tools to decrease dioxin levels in the soils. The predominant bacteria from two sites with elevated dioxin/furan contamination were isolated from whole soil and identified by cellular fatty acid profiles obtained by derivatization to methyl esters (FAMEs). High proportions of Pseudomonas veroni and Pseudomonas fluorescens (biotype A and B) were found in the contaminated sites compared to the uncontaminated sites where Fluorescens putida biotype A appeared to predominate.

Impacts
(N/A)

Publications

  • Kantiani, L., Farre, M., Asperger, D., Rubio, F., Gonzalez, S., Lopez De Alda, M., Petrovic, M., Shelver, W.L., Barcelo, D. 2008. Triclosan and methyl-triclosan monitoring study in the northeast of Spain using a magnetic particle enzyme immunoassay and confirmatory analysis by gas chromatography-mass spectrometry. Journal of Hydrology 361:1-9.
  • Xu, T., Cho, I., Wang, D., Rubio, F.M., Shelver, W.L., Gasc, A.M., Li, J., Li, Q.X. 2009. Suitability of magnetic particle immunoassay for the analysis of PBDEs in Hawaiian freshwater fish and crabs in comparison with gas chromatography/electron capture detection-ion trap mass spectrometry. Environmental Pollution 157:417-422.
  • Kopf, P.G., Huwe, J.K., Walker, M.K. 2008. Hypertension, cardiac hypertrophy, and impaired vascular relaxation induced by 2,3,7,8- tetrachlorodibenzo-p-dioxin are associated with increased superoxide. Cardiovascular Toxicology 8:181-193.
  • Hakk, H., Huwe, J.K., Larsen, G.L. 2009. Absorption, Distribution, Metabolism and Excretion (ADME) Study with 2,2',4,4',5,6' Hexabromodiphenyl Ether (BDE 154) in Male Sprague-Dawley Rats. Xenobiotica. 39:46-56.
  • Dungan, R.S., Huwe, J.K., Chaney, R.L. 2009. Concentrations of PCDD/PCDFs and PCBs in spent foundry sands. Chemosphere. 75:1232-1235.


Progress 10/01/07 to 09/30/08

Outputs
Progress Report Objectives (from AD-416) In order to reduce exposure to dioxins and other environmental contaminants from the food supply, four objectives have been outlined for this research project. 1) Develop inexpensive, rapid, sensitive, assays or improved diagnostic tools to screen samples for dioxins, pesticides, chemical residues, and other environmental contaminants. 2) Investigate sources which contribute to levels of these contaminants in food animals and identify intervention strategies that may reduce the levels. 3) Investigate the uptake, metabolism, distribution, excretion, and fate after excretion of environmental contaminants in animal systems. 4) Update data on levels of dioxins and related compounds in the domestic food supply to provide Food Safety agencies with an adequate profile of the situation and confirm the safety, security, and competitiveness of U. S. foods and food supply. Approach (from AD-416) New tools, such as antibody-based or receptor-based assays, that make analyses cheaper and less time consuming, will be developed to facilitate monitoring of targeted chemicals in the food supply. Sources that contribute to livestock exposure throughout the production process will be investigated and cataloged. Once identified these sources may be eliminated or avoided in farming practices in order to prevent or minimize entrance into the food chain. Basic research to determine pharmacokinetic parameters for these pollutants in laboratory and farm animals will be investigated through animal feeding studies. These data will be used to calculate withdrawal intervals, evaluate source attribution, and elucidate strategies to decrease contaminant levels in food animals. In addition to pharmacokinetic parameters, studies on the fate of a chemical dosed to an animal can provide knowledge of basic biological mechanisms that may be exploited to reduce uptake, increase excretion, or enhance degradation of these contaminants, thereby, lowering levels found in animal food products and the environment. Surveys of the general food supply (especially meat and poultry) will be conducted to provide typical levels of these compounds in U.S. foods. Significant Activities that Support Special Target Populations ¿ An evaluation of a two-dimensional gas chromatography/time-of-flight mass spectrometry (GCxGC-TOF) method as a potentially simple, rapid screening method for dioxins and PCBs was made through a collaboration with the ARS Eastern Regional Research Center (ERRC). Our laboratory provided high resolution gas chromatography/high resolution mass spectrometry (HRGC-HRMS) data on dioxins and PCBs in shared samples to assist the researchers at the ERRC in assessing the quality of the new screening approach. The GCxGC-TOF method allowed streamlined sample preparation and proved to be an adequate screening method for 2 important dioxin and PCB congeners, but did not have the sensitivity required to analyze the full panel of toxic dioxins and PCBs. ¿ Experiments were conducted to validate and optimize an ELISA rapid screening test for the environmental contaminant triclosan in food samples (milk and ground chicken). Due to the interferences in the fatty samples, poor results were obtained from either ELISA or GC-MS. Components 1.2.7 & 1.2.9 "Risk Assessment¿& "Food Security¿ ¿ From Oct 1 through July 31, over 70% of the samples collected in a USDA statistical survey of dioxin-like compounds in domestic meat and poultry have been analyzed (see progress report for subordinate project 5442- 32000-011-02R). ¿ In collaborative work with scientists from the ARS Beltsville Agricultural Research Center, our laboratory analyzed foundry sands for dioxins and PCBs. The results showed dioxins and PCBs in the sand at levels that would not exceed EPA requirements in agricultural soils clearing the way for these spent sands to be used for beneficial purposes such as in potting media or as soil amendments. Component 1.1.3 ¿Ecology, Host Pathogen, and Chemical Residue Relationships¿ ¿ Our laboratory analyzed several mouse tissue samples for tetrachlorodibenzo-p-dioxin (TCDD) in support of research being conducted at the University of New Mexico on the toxicity of TCDD and its role in cardiovascular disease. The data generated by our laboratory was used to validate the dose-response of the TCDD and to show that the TCDD persisted in the mouse tissues into adulthood after only a single in utero exposure. ¿ A study with radiolabeled-TCDD in knock out mice was conducted to determine the role of specific enzymes and proteins in the metabolism and clearance of TCDD from animals. Two dose levels were administered to parental strain mice and knockout mice that lacked a specific cytochrome P450 enzyme (CYP1A2), and tissues and excreta were analyzed for TCDD residues. Results showed TCDD accumulating in both strains of mice and supported the conclusion that CYP1A2 was not involved in clearing TCDD from the body. In addition, urinary elimination of TCDD was observed to be facilitated by mouse major urinary protein (mMUP), a protein involved in binding and transporting small, hydrophobic molecules. ¿ Radiolabeled-BDE-153 was synthesized in a four-step procedure and purified in preparation for an absorption, disposition, metabolism, and excretion (ADME) study in rodents. All accomplishments are related to Program 108, ¿Food Safety." Component 1.2.1 ¿Detection¿ Technology Transfer Number of Active CRADAS: 1

Impacts
(N/A)

Publications

  • Huwe, J.K., Hakk, H., Smith, D.J., Diliberto, J.J., Richardson, V., Birnbaum, L.S., Stapleton, H.M. 2008. Comparative absorption and bioaccumulation of polybrominated diphenyl ethers following ingestion via dust and oil in male rats. Environmental Science and Technology 42:2694- 2700.
  • Wang, D., Atkinson, S., Hoover-Miller, A., Shelver, W.L., Li, Q.X. 2008. Simultaneous use of gas chromatography/ion trap mass spectrometry - electron capture detector to improve the analysis of bromodiphenyl ethers in biological and environmental samples. Rapid Communications in Mass Spectrometry 22(5):647-656.
  • Aragon, A.C., Kopf, P.G., Campen, M.J., Huwe, J.K., Walker, M.K. 2008. In utero and lactational 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure: Effects on fetal and adult cardiac gene expression and adult cardiac and renal morphology. Toxicological Sciences 101(2):321-330.
  • Shelver, W.L., Parrotta, C.D., Slawecki, R., Li, Q.X., Barcelo, D., Larcorte, S., Rubio, F.M. 2008. Development of a magnetic particle immunoassay for polybrominated diphenyl ethers and application to environmental and food matrices. Chemosphere 73:S18-S23.
  • Hoh, E., Lehotay, S.J., Mastovska, K., Huwe, J.K. 2008. Evaluation of automated direct sample introduction with comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry for the screening analysis of dioxins of fish oil. Journal of Chromatography A. 1201(1):69- 77.
  • Huwe, J.K., Hakk, H., Birnbaum, L.S. 2008. Tissue distribution of polybrominated diphenyl ethers in male rats and implications for biomonitoring. Environmental Science and Technology 42:7018-7024. doi:10. 1021/es801344a


Progress 10/01/06 to 09/30/07

Outputs
Progress Report Objectives (from AD-416) In order to reduce exposure to dioxins and other environmental contaminants from the food supply, four objectives have been outlined for this research project. 1) Develop inexpensive, rapid, sensitive, assays or improved diagnostic tools to screen samples for dioxins, pesticides, chemical residues, and other environmental contaminants. 2) Investigate sources which contribute to levels of these contaminants in food animals and identify intervention strategies that may reduce the levels. 3) Investigate the uptake, metabolism, distribution, excretion, and fate after excretion of environmental contaminants in animal systems. 4) Update data on levels of dioxins and related compounds in the domestic food supply to provide Food Safety agencies with an adequate profile of the situation and confirm the safety, security, and competitiveness of U. S. foods and food supply. Approach (from AD-416) New tools, such as antibody-based or receptor-based assays, that make analyses cheaper and less time consuming, will be developed to facilitate monitoring of targeted chemicals in the food supply. Sources that contribute to livestock exposure throughout the production process will be investigated and cataloged. Once identified these sources may be eliminated or avoided in farming practices in order to prevent or minimize entrance into the food chain. Basic research to determine pharmacokinetic parameters for these pollutants in laboratory and farm animals will be investigated through animal feeding studies. These data will be used to calculate withdrawal intervals, evaluate source attribution, and elucidate strategies to decrease contaminant levels in food animals. In addition to pharmacokinetic parameters, studies on the fate of a chemical dosed to an animal can provide knowledge of basic biological mechanisms that may be exploited to reduce uptake, increase excretion, or enhance degradation of these contaminants, thereby, lowering levels found in animal food products and the environment. Surveys of the general food supply (especially meat and poultry) will be conducted to provide typical levels of these compounds in U.S. foods. Accomplishments Indoor dust as a source of PBDE exposure. Polybrominated diphenyl ethers (PBDEs) are a class of flame retardants that have been shown to persist and bioaccumulate in the environment, in wildlife, and in humans. Like other persistent environmental contaminants, human exposure to PBDEs is thought to occur mainly through the food supply; however, recent studies have also implicated the ingestion of indoor dust as a potential exposure pathway. To determine whether PBDEs found in dust are efficiently absorbed after ingestion, our laboratory conducted a study to compare the dietary uptake of PBDEs from either dust or corn oil fed to rats. The study showed that PBDEs found in dust were as readily absorbed by the rats and stored in their tissues as were PBDEs found in fatty foods (i.e. the corn oil). The results support the hypothesis that, in addition to dietary exposure, ingestion of indoor dusts may be a significant route of exposure to PBDEs for humans. (Program 108, ¿Food Safety¿, Component 1.1. 3 ¿Ecology, Host Pathogen, and Chemical Residue Relationships¿.) Skinless, trimmed chicken has reduced PBDE contamination. Studies in mammals have shown that tissues such as adipose and skin are major depots for persistent polybrominated diphenyl ethers (PBDE¿s). Because humans commonly consume the skin of a chicken, it was of interest to conduct an adsorption, tissue disposition, metabolism and excretion study in this production avian species with the most persistent PBDE found in the environment, i.e. 2,2',4,4'-tetrabromodiphenyl ether (BDE-47). Results demonstrated that BDE-47 was well absorbed by the chicken, was not readily metabolized (<1% of the dose), and was mainly distributed to adipose tissue and skin. The data showed that the behavior of BDE-47 in chickens was similar to that observed in mammals; therefore, to reduce human exposure to PBDEs from chicken consumption skin and fat should be trimmed. (Program 108, ¿Food Safety¿, Component 1.1.3 ¿Ecology, Host Pathogen, and Chemical Residue Relationships¿.) Development of a rapid assay for triclosan. Triclosan is a broad spectrum antibiotic often incorporated into personal care products that is also registered as a pesticide by the US-EPA. The widespread use of triclosan has raised concerns about the environmental impact of triclosan residues as well as food safety problems caused by its presence in foods. A sensitive magnetic particle-based immunoassay (IA) to determine triclosan has been developed. The IA could detect triclosan at 20 ppt and its metabolite methyl-triclosan at 15 ppt. As a first step to confirm the usefulness of the triclosan IA towards real world samples, water and wastewater treatment plant samples were analyzed. The IA measurement was shown to be equivalent to expensive, time-consuming, instrumental analysis on a number of wastewater treatment samples with a high degree of correlation. The triclosan magnetic particle immunoassay has been shown to be a rapid, sensitive, precise, and cost-effective monitoring tool for chemical residue. (Program 108, ¿Food Safety¿, Component 1.1.1 ¿Methodology¿.) Technology Transfer Number of Non-Peer Reviewed Presentations and Proceedings: 7 Number of Newspaper Articles,Presentations for NonScience Audiences: 1

Impacts
(N/A)

Publications

  • Shelver, W.L., Kamp, L.M., Church, J.L., Rubio, F.M. 2006. Development of a magnetic particle enzyme immunoassay and its application to the measurement of triclosan in water and wastewater. Organohalogen Compounds 68.
  • Staskal, D.F., Hakk, H., Bauer, D., Diliberto, J.J., Birnbaum, L.S. 2006. Toxicokinetics of Polybrominated Diphenyl Ether Congeners 47, 99, 100, and 153 in Mice. Toxicological Sciences 94(1):28-37.
  • Fan, Z., Casey, F., Larsen, G.L., Hakk, H. 2006. Fate and transport of 1278-TCDD, 1378-TCDD, and 1478-TCDD in soil-water systems. Science of the Total Environment. 371:323-333.
  • Gullett, B.K., Touati, A., Huwe, J.K., Hakk, H. 2006. PCDD and PCDF emissions from simulated sugarcane field burning. Environmental Science and Technology. 40(20):6228-6234.
  • Huwe, J.K., Smith, D.J. 2007. Accumulation, Whole-body Depletion, and Debromination of Decabromodiphenyl Ether (BDE-209) in Male Sprague-Dawley Rats Following Dietary Exposure. Environmental Science and Technology 41:2371-2377.
  • Shelver, W.L., Kamp, L.M., Church, J.L., Rubio, F.M. 2007. The measurement of triclosan in water using a magnetic particle enzyme immunoassay. Journal of Agriculture and Food Chemistry 55:3758-3763.
  • Huwe, J.K., Hakk, H., Lorentzsen, M.K. 2007. Bioavailability and mass balance studies of a commercial pentabromodiphenyl ether mixture in male Sprague-Dawley rats. Chemosphere 66:259-266.
  • Hoffman, M.K., Huwe, J.K., Deyrup, C.L., Lorentzsen, M.K., Zaylskie, R.G., Clinch, N.R., Saunders, P., Sutton, W.R. 2006. Statistically-Designed Survey of Polychlorinated Dibenzo-p-Dioxins, Polychlorinated Dibenzofurans and Co-Planar Polychlorinated Biphenyls in U.S. Meat and Poultry, 2002- 2003: Results, Trends, and Implications. Environmental Science and Technology. 40:5340-5346
  • Huwe, J.K. Uptake of dioxin-like compounds in growing swine: correlation between experimental and predicted data. Organohalogen Compounds 68.
  • Shelver, W.L., Rubio, F.M. Comparison of soil PBDE levels using HRGC-HRMS and magnetic particle enzyme immunoassay. Organohalogen Compounds 68.
  • Smith, D.J., Hakk, H., Larsen, G.L. 2006. Tissue distribution, elimination, and metabolism of sodium [36cl]perchlorate in lactating goats. Journal of Agriculture and Food Chemistry 54:8829-8835.


Progress 10/01/05 to 09/30/06

Outputs
Progress Report 1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter? Persistent organic pollutants such as polychlorinated dioxins, furans, and biphenyls are ubiquitous in the environment and enter the food chain as animals are exposed through their surroundings and feed. These toxic contaminants are concentrated in animal products containing fats (i.e. meat, dairy, and eggs) and are ultimately consumed by humans. The health risk to humans of these low-level contaminants is not adequately known, but dioxins and related compounds have been shown to have numerous adverse health effects in animals. One of the most potent dioxins (2,3,7, 8-tetrachlorodibenzo-p-dioxin or TCDD) has been classified as a known human carcinogen by the World Health Organization (WHO) and U.S. National Toxicology Program (NTP). WHO and the European Union (EU) have set limits on the acceptable levels of these contaminants in food products. Recent recalls of chickens in the U.S. and Belgium with higher than acceptable levels demonstrates the potential for exposures. Our research efforts are directed at reducing exposure to dioxins and other environmental contaminants from the food supply by 1) developing rapid, lower cost methods to analyze for these chemicals, 2) identifying and reducing potential sources of livestock exposure to these toxic chemicals, 3) exploring the uptake, excretion, and fate of these chemicals in animals raised for food and the environment to minimize their entrance into the food chain, and 4) determining current levels and trends of these contaminants in the domestic meat supply. Less expensive methods of analysis will allow widespread monitoring for dioxins and other environmental contaminants in foods minimizing the risks associated with episodic contaminations. Investigation into potential sources of dioxins, such as pentachlorophenol-treated wood or agricultural burning practices, will help determine the contribution of these sources to livestock contamination and whether changes in certain farming practices may be needed. Basic research on absorption, disposition, metabolism, and excretion (ADME) in livestock and fate after excretion in the environment will improve pharmacokinetic modeling of these persistent pollutants and explore mechanism that could help to decrease levels in animals and the environment. More data on the current levels of these contaminants in domestic meat will provide regulators with a better idea of the safety of the U.S. food supply and its acceptability under the new EU regulations. The research relates to Food Safety, National Program 108 (100%). 2. List by year the currently approved milestones (indicators of research progress) Objective 1 (Rapid assays). Year 1 (2006): Develop and evaluate (sensitivity, cross reactivity etc) antibody assays for polybrominated diphenyl ethers (PBDEs) in food matrices. Evaluate the protein CYP 1A2 for binding with dioxin-like compounds (DLCs) for use as a potential bioassay receptor. Year 2 (2007): Validate PBDE ELISA with GC/MS. Generate new antibodies for relevant chemicals i.e. triclosan or tetrabromo-bis-phenol A (TBBPA). Year 3 (2008): Develop and evaluate triclosan ELISA for food matrices. Develop biosensor format for PBDEs, DLCs, and pesticides. Year 4 (2009): Develop and evaluate broad spectrum immunoaffinity columns (IACs) for dioxins in food matrices. Generate new antibodies as needed. Year 5 (2010): Validate biosensor formats for PBDEs, DLCs, and pesticides. Further IAC work as needed. Objective 2 (Identify sources). Year 1 (2006): Recruit and contact collaborators for source cataloging study in beef; design and begin sample collection. Develop a cleanup method for soil analysis of DLCs. Begin burning studies with individual 14C-dioxins in pentachlorophenol- treated wood. Year 2 (2007): Finish sample collection for source study in beef and begin analysis for DLCs and possibly PBDEs. Begin analyzing PCDDs in field and backyard burning samples. Finish pentachlorophenol- treated wood burning studies. Year 3 (2008): Finish analyzing samples from source study in beef and evaluate data. Recruit and contact collaborators for next source study phase (e.g. turkeys). Finish field and backyard soil analyses. Design laboratory burn studies with EPA. Year 4 (2009): Collect feed samples for turkey source study and begin analyzing. Year 5 (2010): Finish analysis of turkey feeds and evaluate data. Objective 3 (ADME, fate, and remediation strategies). Year 1 (2006): Complete ADME studies with BDE-154 in rats and begin an ADME study with BDE-47 in chickens. Complete binding study on PBDEs in urine. Repeat ADME study with TCDD in Cyp1A2 knock-out mice. Analyze TCDD and PBDE urine samples by NMR. Begin a Ractopamine remediation study in swine. Begin studies on fate and transport of PCBs in soils. Begin studies on the fate of a non-toxic TCDD or BDE-99 during composting. Year 2 (2007): Synthesize 14C-BDE-153 and 14C-BDE-209. Conduct an ADME study on HxCDD in rats. Conduct an ADME study on perchlorate in a lactating animal. Characterize any dioxin-binding proteins or enzymes involved in dioxin metabolism. Complete a principle component analysis of urines from the TCDD ADME study. Characterize fecal metabolites from the BDE-154 and BDE- 47 ADME studies. Analyze samples and evaluate results from the Ractopamine remediation study. Complete studies on the fate of a non- toxic TCDD during composting. Year 3 (2008): Conduct an ADME study with BDE-153 in rats. Conduct an ADME study with BDE-209 in mice focusing on debromination. Begin a feeding study in beef cattle to determine BCFs and half-lives. Conduct a study on the fate and transport of BDE-47 in soils and composts. Year 4 (2009): Complete half-life study in beef cattle. Begin a feeding study in turkeys to determine BCFs and half- lives. Conduct a fate and transport study on BDE-209 in soils. Study the fate of PCB-77 in composts. Year 5 (2010): Finish turkey half-life study. Study the fate of PCB-126 in composts. Objective 4 (Current levels in food). Year 1 (2006): none. Year 2 (2007): none. Year 3 (2008): Collect samples for a market basket survey and/or a new survey with FSIS. Year 4 (2009): Analyze all samples for DLCs and PBDEs. Year 5 (2010): Evaluate results and future research directions. 4a List the single most significant research accomplishment during FY 2006. Perchlorate transfer into milk of a lactating animal. Program 108, Food Safety, Component 1.1.3 Ecology, Host Pathogen, and Chemical Residue Relationships. Perchlorate is a strong oxidizing agent that occurs naturally at very low concentrations in ground waters and has contaminated several locations within the United States as a result of industrial use. Because perchlorate at high doses can inhibit processes within the human thyroid gland, some in the scientific community have expressed concern that developing infants and children may be more sensitive to the effects of perchlorate than adults. This concern was accentuated with the discovery of perchlorate in commercial milk samples and in human breast milk. Therefore a study was conducted to determine how much of a perchlorate dose is excreted in the milk of lactating animals i.e. dairy goats. We showed that although most of the perchlorate dosed to goats was converted to chloride (a component of table salt) prior to excretion, a significant portion of the perchlorate was excreted intact into milk. The perchlorate was completely excreted in milk and urine within 72 hours of dosing, indicating that perchlorate does not accumulate in lactating ruminants and is rapidly cleared. 4b List other significant research accomplishment(s), if any. Debromination and persistence of the flame retardant Deca-BDE. Program 108, Food Safety, Component 1.1.3 Ecology, Host Pathogen, and Chemical Residue Relationships. Deca-BDE is an additive flame retardant produced in high volume and incorporated into numerous consumer goods ranging from upholsteries to electronics. Recently other polybrominated diphenyl ether formulations (BDE-types of flame retardants) have been withdrawn from production due to persistence and toxicity issues. The persistence and toxicity of Deca-BDE is currently being re-evaluated. In a six-week feeding study in rats, we investigated the fate and persistence of the major component of Deca-BDE, namely BDE-209. Results of the study showed that BDE-209 is minimally bioavailable but is more persistent than previously reported and is debrominated in rats to more highly persistent lower brominated compounds. These data will be of interest to regulatory agencies and the scientific community evaluating the safety of Deca-BDE. 5. Describe the major accomplishments to date and their predicted or actual impact. The research reported for this CRIS is conducted under National Program 108, Food Safety, and directly contributes to the Chemical Residue Component. Research activities are further related to ARS Strategic Plan Goal 3, Enhance protection and safety of the Nations agriculture and food supply; Objective 3.1, Provide science-based knowledge on the safe production, storage, processing, and handling of plant and animal products and on the detection and control of toxin-producing and/or pathogenic bacteria and fungi parasites, mycotoxins, chemical residues, and plant toxins so as to assist regulatory agencies and the food industry in reducing the incidence of foodborne illnesses. Development of an immunoassay for polybrominated diphenyl ethers. Polybrominated diphenyl ethers (PBDEs) are persistent environmental contaminants that can accumulate through the food chain, but rapid inexpensive methods of detection are not available. Antibodies were generated and incorporated into a rapid screening assay (magnetic particle immunoassay) with the collaboration of Abraxis, LLC. The assay is successful in detecting PBDEs in human milk, chicken meat, fish, water, and soil samples with high specificity and sensitivity. The cost and turn-around time for this new assay is significantly less than that of the traditional PBDE analysis; and, therefore, its use may result in affordable, widespread, monitoring of these persistent pollutants. (ARS performance measures 3.1.1.1 and 3.1.2.1) Fate and transport of dioxins in soils. Dioxins are persistent pollutants principally formed by combustion and incineration processes and deposited on the ground; however, little is known about their potential to migrate through the soil into ground water. The fate and transport of three particular dioxins through soil was studied in various soil columns. The dioxins adhered to the soils based on the organic content and surface area of the soil, but 15-42% of the dioxins were transported through the soil columns with water infiltration. These results suggest that dioxins deposited on the surface may reach ground water reservoirs by preferential flow or colloidal transport. (ARS performance measure 3.1.1.3). Surveys of dioxins and other environmental contaminants in U.S. meat. Five hundred ten meat samples (beef, market hogs, young chickens, and young turkeys) were collected from slaughter houses across the U.S. and analyzed for dioxins. Polybrominated diphenyl ethers (PBDEs) and dioxins were also analyzed in a smaller market basket study that consisted of bacon, chicken, ground beef, sirloin steak, and pork chops collected from grocery stores across the U.S. Dioxins in domestic meat products were low and at similar levels as found in Europe and Japan. Dioxins in chicken, turkey, and pork appeared to have declined in the past ten years while beef did not show as much change. In this first report on PBDEs in U.S. meats, PBDEs in chicken averaged ten-times higher in the U.S. than other countries. Knowledge of current contaminant levels in foods are important to track trends of these contaminants in the food supply, to provide more accurate estimates of human dietary intakes for risk assessment purposes, and to demonstrate the quality of U.S. foods, especially for export purposes. Individual food data can also be valuable to industry and regulatory agencies in tracking down sources of contamination. EPA scientists plan to use this data in their reassessment of dioxin. (ARS performance measures 3.1.2.1 and 3.1.2.7) Transfer of dioxins from feed into cows milk. In 2002 a dioxin- contaminated mineral supplement was discovered which had been used by poultry, pork, and dairy producers in the U.S. A study was conducted to determine how much of the dioxin contamination may have been incorporated into food products. Dairy cows fed a dioxin-contaminated mineral supplement excreted 30% of the consumed dioxins into their milk; however, milk from Minnesota dairies that had purchased the contaminated supplement did not show elevated levels of dioxins. It was concluded that although dioxins from the mineral supplement were readily transferred into cows milk, the level of dioxins in the finished feeds used on MN farms was low enough to not cause a significant increase in the dioxin levels in milk, thus leading to no elevated risk to the consumer. Studies on the transfer of dioxins from feed or feed ingredients into animal products, such as milk, provide important information (e.g. bioconcentration factors and withdrawal rates) to regulatory agencies when assessing the potential risk of a contamination incident. (ARS performance measures 3.1.1.3 and 3.1.1.4). Pharmacokinetic studies of polybrominated diphenyl ethers. The bioavailability and bioaccumulation of PBDEs were determined by feeding studies in rats using two commercial mixtures: one contained tetra- to hexa-BDEs and one contained hexa- to octa-BDEs. Purification methods and GC/MS detection methods were developed to analyze the PBDEs in excreta and tissues. Results of the studies showed that all the congeners were bioavailable to varying extents (15-60%) and were supported by other studies conducted in rats using single compounds (pentaBDEs-99 and -100, and decaBDE). All studies showed that the potential for these contaminants to accumulate through the food supply decreases with increasing bromine content, supporting the decision by industry to cease production of the penta- and octa-formulations while retaining only the decaBDE product. BDEs-47, 99, 100, and 153 were identified as potential markers for PBDE contamination in the food supply. (ARS performance measures 3.1.1.1 and 3.1.1.3) The role of Cytochrome P450-1A2 in dioxin excretion. Toxic dioxin congeners are extremely persistent in animal systems and methods to increase clearance from the body are needed. The roles of Cytochrome P450-1A2 (Cyp 1A2) and metabolism in the sequestration and clearance of dioxins were investigated using knockout mice (designed to possess no Cyp 1A2). A comparison of the metabolism and excretion of two toxic dioxins (TCDD and PeCDD) in regular and knockout mice showed that even in the absence of Cyp 1A2, a dioxin-sequestering protein, no increase in metabolism or excretion occurred. The inherent resistance of dioxins to metabolic change and, thereby, excretion means that other approaches to decrease body burdens may need to be explored. (ARS performance measures 3.1.1.3 and 3.1.1.4) Remediation of dioxins with ractopamine. In a remediation study, rats lost 30% of their body fat when fed clenbuterol (a leanness-enhancing agent) in their diet compared to controls; the amount of dioxin in the fat stores after a dioxin exposure also decreased by 30% when clenbuterol was fed. These results are encouraging and suggest similar dioxin body burden decreases could be achieved in animals raised for food provided approved leanness-enhancing agents are available. Lowering dioxin levels in the food supply is strongly recommended by the NAS Committee on the Implications of Dioxins in the Food Supply. (ARS performance measures 3.1. 1.3 and 3.1.1.4) 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? A Trust Fund Cooperative Agreement has been established between the ARS and Abraxis LLC for Development of a Magnetic Particle Based Immunoassay for triclosan (No. 58-3K95-5-1106; (Oct 2005). Abraxis has commercialized the triclosan ELISA. A Trust Fund Cooperative Agreement has been established between the ARS and Abraxis LLC for Development of a Magnetic Particle Based Immunoassay for Water Toxin Geosmin (No. 58-3K95-5-1106; April, 2006). A Trust Fund Cooperative Agreement been established between the ARS and Abraxis LLC for a USDA Small Business Innovation Research Program grant entitled Development of Monoclonal and Polyclonal Antibodies Suitable for a Commercial Perfluorooctanoic Acid (PFOA) ELISA (No. 58-5442-6-415; June 2006).

Impacts
(N/A)

Publications

  • Hakk, H., Huwe, J.K., Larsen, G.L. 2005. An ADME study with 2,2',4,4',5,6'- hexabromodiphenyl ether (BDE-154) in male Sprague-Dawley rats. Organohalogen Compounds 67:2339-2342.
  • Huwe, J.K. 2005. Bioaccumulation of decabromodiphenyl ether (BDE-209) from the diet into Sprague-Dawley rats. Organohalogen Compounds 67:633-635.
  • Rubio, F., Parrotta, C.D., Li, Q.X., Shelver, W.L. 2005. Development of sensitive magnetic particle immunoassay for polybrominated diphenyl ethers. Organohalogen Compounds 67:27-30.
  • Rubio, F.M., Parrotta, C.D., Li, Q.X., Barcelo, D., Lacorte, S., Shelver, W.L. 2005. Development of a sensitive magnetic particle immunoassay for polybrominated diphenyl ethers-fish sample application. SETAC North American 26th Annual Conference, Baltmore, MD, Nov. 13-17, 2005.
  • Huwe, J.K., Larsen, G.L. 2005. Dioxins and dioxin-like compounds in domestic meats. Proceedings of the 6th International Symposium on the Epidemiology & Control of Foodborne Pathogens in Pork (SafePork 2005), Sept. 6-9, 2005, Rohnert Park, CA, pp. 129-132.
  • Hakk, H., Huwe, J.K., Low, M.C., Rutherford, D., Larsen, G.L. 2006. Tissue disposition, excretion, and metabolism of 2,2',4,4',6- pentabromodiphenyl ether (BDE-100) in male Sprague-Dawley rats. Xenobiotica 36(1):79-94.
  • Huwe, J.K. 2005. Modern analytical methods for chemical residue detection. Proceedings of MOST-USDA Workshop on Agricultural Products Processing and Food Safety, Sept. 21-24, 2005, Beijing, China, p. 391.
  • Smith, D.J., Hakk, H., Larsen, G.L. 2006. Tissue distribution, elimination, and metabolism of sodium 36cl-perchlorate in lactating goats. American Chemical Society Abstracts. San Francisco, CA, Sept. 10-14, 2006.