Progress 02/08/16 to 08/02/19
Outputs
Progress Report Objectives (from AD-416): Objective 1: Develop and/or validate rapid screening assays for the detection of environmental chemicals relevant to U.S. food production. Sub-objective 1.A: Development of immunochemically based rapid screening methods for new and emerging persistent organic pollutants. Sub-objective 1.B: Development of immunochemical purification methods for new and emerging persistent organic pollutants. Objective 2: Determine levels and sources of dioxins and related compounds in the domestic food supply. Provide food safety agencies with data to confirm or refute the wholesomeness and competitiveness of beef, pork, chickens, turkeys and/or catfish. Sub-objective 2.A: Conduct a nationally-based survey of PCDD/PCDF/PCB/ PBDE levels in the domestic meat supply (beef, pork, chicken, turkey, and/ or catfish) by collection of adipose tissues from U.S. slaughter facilities. Sub-objective 2.B: Identify potential production-based or environmental sources of PCDDs/PCDFs/PCBs/PBDEs in food-producing animals. Objective 3: Determine the uptake, metabolism (in vitro or in vivo), distribution, excretion, and fate of environmental contaminants with the goal of developing pharmacokinetic rate and volume constants pertinent to residue depletion, selection of marker compounds, and calculation of withdrawal intervals. Sub-objective 3.A: Characterize the absorption, disposition, metabolism, and excretion (ADME) of POPs in food animals. Sub-objective 3.B: Identify cellular fractions and enzyme classes responsible for the metabolism and putative dehalogenation of POPs. Sub-objective 3.C: Characterize the bioavailability of POPs in animal systems from major exposure routes. Sub-objective 3.D: Determine the fate and transport of POPs through soil during ambient weather conditions. Sub-objective 3.E: Determine the effect of milk processing on POP concentrations in finished products. Approach (from AD-416): Ubiquitous environmental contaminants enter the human meat supply when animals are exposed through surroundings and feeds. These compounds, known as persistent organic pollutants (POPs) satisfy the standards for chemicals of concern in that they are persistent, bioaccumulative, globally transported, and toxic. U.S. and international health organizations recommend continuing to decrease human exposure by lowering levels in foods and the environment. Our research efforts focus on reducing animal and human exposures to these contaminants using three approaches. First, we will develop rapid, inexpensive assays and cleanup tools for isolating and detecting POPs in food products. These assays could result in broad monitoring of the food supply, which currently is not feasible due to the high analysis costs. Second, we will continue to survey the U.S. meat supply (beef, pork, chicken, turkey and/or catfish) for POPs, and will track current levels with trends measured over the last two decades. These data are critical to regulatory agencies for risk assessment, and have revealed POP sources that have contributed to livestock exposures and contamination. Once identified sources of contamination may be eliminated or avoided. Third, we will perform basic research to determine pharmacokinetic parameters for POPs in laboratory and farm animals and will develop potential remediation methods using animal feeding studies. We will use these data to calculate withdrawal intervals, and elucidate strategies to decrease contaminant levels in food animals. This is the final report for project 3060-32420-002-00-D, ⿿Environmental Chemical Residues and their Impact in the Food Supply which will merge with project, 3020-32420-001-00D, ⿿Detection and Fate of Chemical and Biological Residues in Food and Environmental Systems at the end of fiscal 2019. With respect to Objective 1, ⿿Develop and/or validate rapid screening assays for the detection of environmental chemicals relevant to U.S. food production, progress was made with European cooperators in developing and validating electrochemical immunogenic (antibody based) chemical assays for polybrominated flame retardants (PBFRs) and investigating the best extraction methods for use of the assay. Further, a multiplex fluorescent microarray was developed for measuring a variety of contaminants, including polybrominated flame retardants, in aqueous matrices. Although antigens towards several specific PBFRs (2-ethylhexyl 2,3,4,5-tetrabromobenzoate, TBB; di(2-ethylhexyl)-2,3,4,5- tetrabromophthalate, TBPH) were synthesized, the antibodies produced were not of sufficient sensitivity. Thus, immunochemical screening and quantitative immunoassays were not developed for TBB and TBPH. Progress was made, however on rapid screening and semi-quantitative assays based on hyphenated mass spectrometric methods. For example, brominated estrogens, perflurooctanesulfonate (PFOS), and perfluorohexanesulonate (PFHxS) were successfully measured in environmental and animal matrices using electrospray ionization inlet (ESII) mass spectrometry; the successful demonstration of the technique suggests wide applicability across a variety of important food animal matrices. Brominated estrogens were also measured in environmental matrices using Atmospheric Solids Analysis Probe (ASAP) mass spectrometry. Neither ASAP nor ESII mass spectrometric technique employs chromatographic separation; analytes are measured directly in sample matrices or simple sample extracts. Both techniques provide rapid quantitative or semi-quantitative results. Objective 2, ⿿Determine levels and sources of dioxins and related compounds in the domestic food supply. Provide food safety agencies with data to confirm or refute the wholesomeness and competitiveness of beef, pork, chickens, turkeys and/or catfish, has been investigated in cooperation with the USDA Food Safety and Inspection Service (FSIS). Results of the 2012/2013 survey of dioxins in the US meat supply, which demonstrated a continued trend for a reduction in overall dioxin content of meats produced in the U.S., were summarized and reported during the lifetime of this project plan. An additional survey is currently in progress with the addition of the assessment of a cohort of beef liver samples and Siluriformes (catfish) muscles. Tissues from the 2012/13 survey were also assayed for the presence of a series of polybrominated diphenyl ether (PBDEs) flame retardants that are known to accumulate in animal tissues. An overall decline (25.9 to 70.0%) in the median content of total PDBEs in all four meat classes was measured. PPDE content of U.S. meats gathered during the current survey are also being assessed. An additional cooperative project with the USDA FSIS was initiated designed to characterize residues of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS) and other perfluoroalkyl contaminants in dairy cattle that were chronically exposed to contaminated drinking water. Data from this study were used to develop models of contaminant depletion from blood, edible tissues, and milk. The multi-step approach of Objective 3, ⿿Determine the uptake, metabolism (in vitro or in vivo), distribution, excretion, and fate of environmental contaminants with the goal of developing pharmacokinetic rate and volume constants pertinent to residue depletion, selection of marker compounds, and calculation of withdrawal intervals required a systematic approach. To this end, organic syntheses were required to prepare radiolabeled target compounds including decabromodiphenyl ether (BDE-209), 2,2⿿,4,4⿿,5- pentabromodiphenyl ether (BDE-99), and 2,2⿿,4,4⿿,5,5⿿-hexabromodiphenyl ether (BDE-153). These compounds were orally dosed to laying hens and the overall fate and distribution of each was measured in tissues, excreta, and eggs. Remarkably over 25% of some of the dosed BDEs were transferred to eggs during the 7-day study period. Additionally, syntheses were conducted to produce bromo-chloro mixed halogenated dioxins for use in animal disposition studies. Although demanding with respect to resources, studies such as these provide unambiguous data on the rate and extent to which chemical contaminants may be transferred into food-animal products. Additional studies were completed that investigated the absorption and tissue distribution of dust-bound brominated flame retardants in rats. This study was conducted because a significant route of exposure in humans to such flame retardants is via the ingestion of household dust. Another series of studies investigated the soil transport, soil-to- alfalfa, and alfalfa-to-rat transfer of PFOA. These studies provided the first evidence that plant root systems can delay the transport of the perfluoroalkyl contaminants through the soil. Further, forage crops such as alfalfa, may serve to remediate contaminated soils because the contaminant was transported primarily to the above ground portions of the plant (which can be harvested). The partitioning of environmental contaminants and agrochemicals into economically important fractions of milk (i.e., skim milk, curd, whey, whey proteins) was studied using approximately 27 compounds. Data from the study were used to develop a first-of-kind predictive model based on chemical characteristics such as the octanal/water partition coefficient.
Impacts
(N/A)
Publications
- Kraft, A.L., Lacher, D.W., Shelver, W.L., Sherwood, J.S., Bergholz, T.M. 2017. Comparison of immunomagnetic separation beads for detection of six non-O157 Shiga toxin-producing Escherichia coli serogroups in different matrices. Letters in Applied Microbiology. 65(3):213-219.
- Romanelli, S., Bettazzi, F., Martellini, T., Shelver, W.L., Cincinelli, A., Galarini, R., Palchetti, I. 2017. Evaluation of a QuECHERS-like extraction approach for the determination of PBDEs in mussels by immuno- assay-based screening methods. Talanta. 170:540-545.
|
Progress 10/01/17 to 09/30/18
Outputs
Progress Report Objectives (from AD-416): Objective 1: Develop and/or validate rapid screening assays for the detection of environmental chemicals relevant to U.S. food production. Sub-objective 1.A: Development of immunochemically based rapid screening methods for new and emerging persistent organic pollutants. Sub-objective 1.B: Development of immunochemical purification methods for new and emerging persistent organic pollutants. Objective 2: Determine levels and sources of dioxins and related compounds in the domestic food supply. Provide food safety agencies with data to confirm or refute the wholesomeness and competitiveness of beef, pork, chickens, turkeys and/or catfish. Sub-objective 2.A: Conduct a nationally-based survey of PCDD/PCDF/PCB/ PBDE levels in the domestic meat supply (beef, pork, chicken, turkey, and/ or catfish) by collection of adipose tissues from U.S. slaughter facilities. Sub-objective 2.B: Identify potential production-based or environmental sources of PCDDs/PCDFs/PCBs/PBDEs in food-producing animals. Objective 3: Determine the uptake, metabolism (in vitro or in vivo), distribution, excretion, and fate of environmental contaminants with the goal of developing pharmacokinetic rate and volume constants pertinent to residue depletion, selection of marker compounds, and calculation of withdrawal intervals. Sub-objective 3.A: Characterize the absorption, disposition, metabolism, and excretion (ADME) of POPs in food animals. Sub-objective 3.B: Identify cellular fractions and enzyme classes responsible for the metabolism and putative dehalogenation of POPs. Sub-objective 3.C: Characterize the bioavailability of POPs in animal systems from major exposure routes. Sub-objective 3.D: Determine the fate and transport of POPs through soil during ambient weather conditions. Sub-objective 3.E: Determine the effect of milk processing on POP concentrations in finished products. Approach (from AD-416): Ubiquitous environmental contaminants enter the human meat supply when animals are exposed through surroundings and feeds. These compounds, known as persistent organic pollutants (POPs) satisfy the standards for chemicals of concern in that they are persistent, bioaccumulative, globally transported, and toxic. U.S. and international health organizations recommend continuing to decrease human exposure by lowering levels in foods and the environment. Our research efforts focus on reducing animal and human exposures to these contaminants using three approaches. First, we will develop rapid, inexpensive assays and cleanup tools for isolating and detecting POPs in food products. These assays could result in broad monitoring of the food supply, which currently is not feasible due to the high analysis costs. Second, we will continue to survey the U.S. meat supply (beef, pork, chicken, turkey and/or catfish) for POPs, and will track current levels with trends measured over the last two decades. These data are critical to regulatory agencies for risk assessment, and have revealed POP sources that have contributed to livestock exposures and contamination. Once identified sources of contamination may be eliminated or avoided. Third, we will perform basic research to determine pharmacokinetic parameters for POPs in laboratory and farm animals and will develop potential remediation methods using animal feeding studies. We will use these data to calculate withdrawal intervals, and elucidate strategies to decrease contaminant levels in food animals. Objective 1A. 2-ethylhexyl-2,3,4,5 tetrabromobenzoate (TBB) and bis(2- ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH) haptens have been synthesized, conjugated to proteins to produce coating antigens and immunogens. The rabbit immunizations are completed, antibodies have been collected, and the titers for sensitivity are being performed. Objective 2B. Two turkey producer associations across the Midwest have pledged support for a study to analyze for polybrominated diphenyl ethers. However, time commitments have prevented initiation of study/sampling protocols to be developed yet. Objective 3A1. Due to difficulty in synthesizing this highly toxic compound, research effort was directed toward chemical relatives, i.e., mixed bromo/chloro-dioxins which are produced by the same pathways as the toxic chloro-dioxins, but whose pharmacokinetics have not been determined. Objective 3A2. Absorption, distribution, metaoblism and excretion research in food animals was diverted to three related persistent organic pollutants, namely brominated diphenyl ethers in laying chickens. The ADME studies are completed and animal tissues are being processed and analyzed. Objective 3B. Microsomal and S9 fractions have been isolated from dairy cows. However, characterization methods and experimental procedures have not been validated for the in vitro metabolism assays. Objective 3C2. The hexabromocyclododecane (HBCD)/TBB/TBPH bioavailability study with incurred feed has been completed in rats, and animal tissues are being processed and analyzed. Objective 3E. The entire study with 12 persistent organic pollutants was performed, completed, and the manuscript has been submitted to the journal. Accomplishments 01 Persistent organic pollutant distribution during milk processing. Milk is a complex food that is often processed into foods such as skim milk, creams, cheeses, and/or whey-based products. During processing, trace- level chemical contaminants might become concentrated in such products depending upon the chemical characteristics of the contaminant. ARS scientists in Fargo, North Dakota determined how 12 common persistent organic pollutants with known chemical properties partitioned into milk fractions used for the production of human foods. The fat solubility of an individual chemical was reasonably predictive of its partitioning into various milk fractions. Collectively, data on the fate of chemicals during milk processing will allow the development of useful predictive models if a contamination event occurs. 02 Bioavailability of brominated flame retardants. Brominated flame retardants (BFRs) are commonly applied to consumer products to reduce the risk of fires. However, some BFRs are believed to be toxic and are of human health concern because humans are exposed to BFRS from a variety of sources and they could be absorbed in the gut. A major route of exposure to BFRs, especially in children, is through the consumption of household dust. Agricultural Research Service scientists in Fargo, North Dakota measured the levels of three major BFRs in household dust, fed the dust to rats, and measured the appearance of each BFR in rat tissues. The researchers learned that each BFR was readily absorbed from household dust and that each preferentially accumulated in fat tissue. These results will be used by risk assessors when predicting the overall hazards to humans of BFRs from all sources.
Impacts
(N/A)
Publications
- Hakk, H., Sikora, L.S., Casey, F.X. 2018. Fate of estrone in laboratory- scale constructed wetlands. Ecological Engineering. 111:60-68.
- Sanchis, A., Salvador, J.P., Campbell, K., Elliott, C.T., Shelver, W.L., Li, Q.X., Marco, M.P. 2018. Fluorescent microarray for multiplexed quantification of environmental contaminants in seawater samples. Talanta. 184:499-506.
- Lupton, S.J., Shappell, N.W., Shelver, W.L., Hakk, H. 2018. Distribution of spiked drugs between milk fat, skim milk, whey, curd, and milk protein fractions: Expansion of partitioning models. Journal of Agricultural and Food Chemistry. 66(1):306-314.
- Singh, A., Hakk, H., Lupton, S.J. 2018. Facile synthesis of high specific activity 4-[1-14C]butyl-1,2-diphenylpyrazolidine-3,5-dione (phenylbutazone) using nucleophilic substitution. Journal of Labelled Compounds and Radiopharmaceuticals. 61(4):386-390.
- Shelver, W.L., Lupton, S.J., Shappell, N.W., Smith, D.J., Hakk, H. 2018. Distribution of chemical residues among fat, skim, curd, whey, and protein fractions in fortified, pasteurized milk. ACS Omega. 3(8):8697-8708.
|
Progress 10/01/16 to 09/30/17
Outputs
Progress Report Objectives (from AD-416): Objective 1: Develop and/or validate rapid screening assays for the detection of environmental chemicals relevant to U.S. food production. Sub-objective 1.A: Development of immunochemically based rapid screening methods for new and emerging persistent organic pollutants. Sub-objective 1.B: Development of immunochemical purification methods for new and emerging persistent organic pollutants. Objective 2: Determine levels and sources of dioxins and related compounds in the domestic food supply. Provide food safety agencies with data to confirm or refute the wholesomeness and competitiveness of beef, pork, chickens, turkeys and/or catfish. Sub-objective 2.A: Conduct a nationally-based survey of PCDD/PCDF/PCB/ PBDE levels in the domestic meat supply (beef, pork, chicken, turkey, and/ or catfish) by collection of adipose tissues from U.S. slaughter facilities. Sub-objective 2.B: Identify potential production-based or environmental sources of PCDDs/PCDFs/PCBs/PBDEs in food-producing animals. Objective 3: Determine the uptake, metabolism (in vitro or in vivo), distribution, excretion, and fate of environmental contaminants with the goal of developing pharmacokinetic rate and volume constants pertinent to residue depletion, selection of marker compounds, and calculation of withdrawal intervals. Sub-objective 3.A: Characterize the absorption, disposition, metabolism, and excretion (ADME) of POPs in food animals. Sub-objective 3.B: Identify cellular fractions and enzyme classes responsible for the metabolism and putative dehalogenation of POPs. Sub-objective 3.C: Characterize the bioavailability of POPs in animal systems from major exposure routes. Sub-objective 3.D: Determine the fate and transport of POPs through soil during ambient weather conditions. Sub-objective 3.E: Determine the effect of milk processing on POP concentrations in finished products. Approach (from AD-416): Ubiquitous environmental contaminants enter the human meat supply when animals are exposed through surroundings and feeds. These compounds, known as persistent organic pollutants (POPs) satisfy the standards for chemicals of concern in that they are persistent, bioaccumulative, globally transported, and toxic. U.S. and international health organizations recommend continuing to decrease human exposure by lowering levels in foods and the environment. Our research efforts focus on reducing animal and human exposures to these contaminants using three approaches. First, we will develop rapid, inexpensive assays and cleanup tools for isolating and detecting POPs in food products. These assays could result in broad monitoring of the food supply, which currently is not feasible due to the high analysis costs. Second, we will continue to survey the U.S. meat supply (beef, pork, chicken, turkey and/or catfish) for POPs, and will track current levels with trends measured over the last two decades. These data are critical to regulatory agencies for risk assessment, and have revealed POP sources that have contributed to livestock exposures and contamination. Once identified sources of contamination may be eliminated or avoided. Third, we will perform basic research to determine pharmacokinetic parameters for POPs in laboratory and farm animals and will develop potential remediation methods using animal feeding studies. We will use these data to calculate withdrawal intervals, and elucidate strategies to decrease contaminant levels in food animals. Objective 1A. The TBB hapten has been conjugated to bovine serum albumin and keyhole limpet hemocyanin (KLH). The TBB-KLH conjugate has been shipped to a commercial firm to generate rabbit antisera. The sensitivity of the TBB-antisera towards TBB was determined. Objective 2B. Turkey producer associations across Minnesota, North Dakota and South Dakota have been contacted about participation in sample collection (animal tissue, feed, environmental, and housing). Two associations have pledged support for a study to analyze for polybrominated diphenyl ethers. Objective 3A1. Radiolabeled [14C]BDE-153 has been synthesized to allow milking goat metabolism study to be conducted. Objective 3A2. [14C]BDE-153 has been synthesized; animal use protocols are being developed. Due to difficulty in obtaining milking goats a different species for study is being considered. Objective 3B. Microsomal and S9 fractions have been isolated from dairy cows. Characterization methods and experimental procedures are being validated for the in vitro metabolism assays. Objective 3C. The bioavailability study with incurred feed has been completed, and animal tissues are being processed and analyzed. Objective 3E. Milk partitioning experiments have been completed on a representative dioxin, polybrominated diphenyl ether, hexabromocyclododecane, polychlorinated biphenyl, and tetrabromo- bisphenol-A; metabolites of dioxin and PCB have also been formed through in vitro metabolism and tested in the milk system. Accomplishments 01 Plant uptake and mammalian bioavailability of PFOA. Perfluoroctanoic acid (PFOA) is used in industrial and consumer products including coatings for paper and fabrics, fire-fighting foams, and stain- resistant household items. The presence of PFOA in bio-solids from wastewater treatment plants, which are commonly used as fertilizers on agricultural lands, has raised concerns because of potential PFOA uptake by plants and consumption by animals or humans. ARS scientists at Fargo, North Dakota conducted sequential studies to quantify the uptake of soil-borne PFOA into alfalfa and then to determine the extent of PFOA absorption from alfalfa by rats (a model for humans). PFOA residues were transferred from soil to alfalfa and most of the PFOA incorporated into alfalfa was absorbed by rats after feeding. However, the PFOA absorbed by rats was rapidly eliminated. The research clearly demonstrated that PFOA is absorbed by plants and subsequently by mammals consuming contaminated forage. This data will help risk assessors determine the long-term hazards of using PFOA contaminated soils for food production. 02 Rapid screening method for environmental contaminants. Polybrominated diphenyl ethers (PBDEs) are fire retardants that have been widely used extensively in building materials, electronics, and plastics. Because of their toxicity, environmental persistence, bioaccumulation in animals, and global transport, a variety of PBDEs have been banned in the European Union since 2008. Nevertheless, PBDEs are still consistently detected in environmental and food samples. In collaboration with researchers at University of Florence, Italy, an ARS scientist at Fargo, North Dakota developed an electrochemical immunoassay screening assay for PBDEs. An array of electrodes allows the rapid, reliable and economical measurements of several samples simultaneously and when used for the analysis of food samples the results correlated well with those obtained using slower, more tedious instrumental analysis. The developed assay could reduce the expense and time required to determine PBDEs in food and environmental samples.
Impacts
(N/A)
Publications
- Hakk, H. 2016. Comparative metabolism studies of hexabromocyclododecane (HBCD) diastereomers in male rats following a single oral dose. Environmental Science and Technology. 50(1):89-96.
- Bettazii, F., Martellini, T., Shelver, W.L., Cincinelli, A., Lanciotti, E., Palchetti, I. 2016. Development of an electrochemical immunoassay for the detection of polybrominated diphenyl ethers (PBDEs). Electroanalysis. 28(8) :1817-1823. doi:10.1002/elan.201600127.
- Lupton, S.J., O'Keefe, M., Muniz Ortiz, J.G., Clinch, N., Basu, P. 2017. Survey of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and non-orthopolychlorinated biphenyls in U.S. meat and poultry from 2012- 2013: Toxic equivalency levels, patterns, temporal trends, and implication. Food Additives & Contaminants. 34(11):1970-1981.
- Lupton, S.J., Hakk, H. 2017. Polybrominated diphenyl ethers (PBDEs) in U.S. meat and poultry: 2012-13 levels, trends, and estimated consumer exposures. Food Additives & Contaminants. Part A. 34(9):1584-1595.
|
Progress 10/01/15 to 09/30/16
Outputs
Progress Report Objectives (from AD-416): Objective 1: Develop and/or validate rapid screening assays for the detection of environmental chemicals relevant to U.S. food production. Sub-objective 1.A: Development of immunochemically based rapid screening methods for new and emerging persistent organic pollutants. Sub-objective 1.B: Development of immunochemical purification methods for new and emerging persistent organic pollutants. Objective 2: Determine levels and sources of dioxins and related compounds in the domestic food supply. Provide food safety agencies with data to confirm or refute the wholesomeness and competitiveness of beef, pork, chickens, turkeys and/or catfish. Sub-objective 2.A: Conduct a nationally-based survey of PCDD/PCDF/PCB/ PBDE levels in the domestic meat supply (beef, pork, chicken, turkey, and/ or catfish) by collection of adipose tissues from U.S. slaughter facilities. Sub-objective 2.B: Identify potential production-based or environmental sources of PCDDs/PCDFs/PCBs/PBDEs in food-producing animals. Objective 3: Determine the uptake, metabolism (in vitro or in vivo), distribution, excretion, and fate of environmental contaminants with the goal of developing pharmacokinetic rate and volume constants pertinent to residue depletion, selection of marker compounds, and calculation of withdrawal intervals. Sub-objective 3.A: Characterize the absorption, disposition, metabolism, and excretion (ADME) of POPs in food animals. Sub-objective 3.B: Identify cellular fractions and enzyme classes responsible for the metabolism and putative dehalogenation of POPs. Sub-objective 3.C: Characterize the bioavailability of POPs in animal systems from major exposure routes. Sub-objective 3.D: Determine the fate and transport of POPs through soil during ambient weather conditions. Sub-objective 3.E: Determine the effect of milk processing on POP concentrations in finished products. Approach (from AD-416): Ubiquitous environmental contaminants enter the human meat supply when animals are exposed through surroundings and feeds. These compounds, known as persistent organic pollutants (POPs) satisfy the standards for chemicals of concern in that they are persistent, bioaccumulative, globally transported, and toxic. U.S. and international health organizations recommend continuing to decrease human exposure by lowering levels in foods and the environment. Our research efforts focus on reducing animal and human exposures to these contaminants using three approaches. First, we will develop rapid, inexpensive assays and cleanup tools for isolating and detecting POPs in food products. These assays could result in broad monitoring of the food supply, which currently is not feasible due to the high analysis costs. Second, we will continue to survey the U.S. meat supply (beef, pork, chicken, turkey and/or catfish) for POPs, and will track current levels with trends measured over the last two decades. These data are critical to regulatory agencies for risk assessment, and have revealed POP sources that have contributed to livestock exposures and contamination. Once identified sources of contamination may be eliminated or avoided. Third, we will perform basic research to determine pharmacokinetic parameters for POPs in laboratory and farm animals and will develop potential remediation methods using animal feeding studies. We will use these data to calculate withdrawal intervals, and elucidate strategies to decrease contaminant levels in food animals. Objective 1A. The TBB hapten has been conjugated to bovine serum albumin and keyhole limpet hemocyanin (KLH). The TBB-KLH conjugate has been shipped to a commercial firm to generate rabbit antisera. Objective 2B. Turkey producer associations across Minnesota, North Dakota and South Dakota have been contacted about participation in sample collection (animal tissue, feed, environmental, and housing). Two associations have pledged support for a study to analyze for polybrominated diphenyl ethers. Objective 3A1. Radiolabeled [14C]BDE-153 has been synthesized to allow milking goat metabolism study to be conducted. Objective 3A2. [14C]-BDE-153 has been synthesized; animal use protocols are being developed; the availability of milking goats is being pursued. Objective 3B. Microsomal and S9 fractions have been isolated from dairy cows. Characterization methods are being validated for the in vitro metabolism assays. Objective 3C. The incurred feed (PFOA into alfalfa) needed to conduct the live (rat) phase study have been prepared and tested. Feed mixtures are prepared and animal protocols have been approved. Objective 3E. Milk partitioning experiments have been completed on a representative dioxin, polybrominated diphenyl ether, hexabromocyclododecane, polychlorinated biphenyl, and tetrabromo- bisphenol-A. Additional compounds to be tested will further span the water-solubility range, but need to be synthesized as radiochemicals. Accomplishments 01 Partitioning of persistent organic pollutants into milk products. It has long been acknowledged that human exposure to fat-loving persistent organic pollutants (POPs) occurs principally through our food. However, very little is known about how POPs may distribute in food products following commercial processing. It may be assumed that POPs would distribute into fatty compartments during processing, however, these types of data have not been generated for POPs that may be present in milk. ARS scientists at Fargo, North Dakota conducted a lab-scale milk processing study with a representative dioxin, polychlorinated biphenyl (PCB), polybrominated diphenyl ether (PBDE), and two high production volume brominated flame retardants (tetrabromobisphenol-A and hexabromocyclododecane) and determined their partitioning from whole milk into skim milk, milk fat, curd, whey, and concentrated whey proteins. Most of the fortified dioxin, PCB, PBDE, and hexabromocyclododecane (HBCD) distributed into the milk fat fraction, and what was left in the skim milk concentrated into the curd during further processing. Tetrabromobisphenol-A (TBBP-A), on the other hand, distributed evenly between milk fat and skim milk, and also between the curd and whey. Finally, liquid whey residues concentrated with the whey protein rather than the water fraction for all POPs tested. The researchers attempted to correlate the results with the chemical properties of each POP, but with no success. However, the result suggested that, depending on the POP, concentrations of these contaminants can increase in processed milk products.
Impacts
(N/A)
Publications
- Hakk, H., Shelver, W.L., Casey, F.X. 2016. Fate and transport of the �- adrenergic agonist ractopamine hydrochloride in soil-water systems. Journal of Environmental Science. 45:40-48.
|
|