CHEMICAL AND BIOLOGICAL RESIDUES IN FOODS
Location: Animal Metabolism-Agricultural Chemicals Research
Title: Absorption and excretion of 14C-perfluorooctanoic acid (PFOA)in angus cattle (Bos taurus)
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 22, 2011
Publication Date: February 1, 2012
Citation: Lupton, S.J., Huwe, J.K., Smith, D.J., Dearfield, K.L., Johnston, J.J. 2012. Absorption and excretion of 14C-perfluorooctanoic acid (PFOA)in angus cattle (Bos taurus). Journal of Agricultural and Food Chemistry. 60:1128-1134.
Interpretive Summary: Perfluorooctanoic acid (PFOA) is an industrial chemical used in the production of a wide range of products for surfactants and coatings, such as Teflon(R) and Scotchgard(TM). PFOA is widely spread in the environment and is found in humans and wildlife. Because this chemical appears to accumulate in the body and has shown adverse health effects in animal studies, it is important to understand the routes of exposure for humans. Due to the fact that biosolids containing PFOA from wastewater treatment plants are spread on cattle pastures and animal food crops, one important route of exposure may be through consumption of contaminated animal products. To determine to what extent agricultural animals such as cattle absorb and accumulate PFOA, we have conducted a study to look at the absorption, distribution, metabolism and excretion of PFOA in Lowline Angus steers. After a single oral dose of PFOA was given to steers, we determined that PFOA is excreted in the urine relatively quickly (within 1 week). There was no remaining PFOA in the edible tissues of the steers indicating acute exposure of steers to PFOA would probably not contribute to exposure of PFOA to humans.
Perfluorinated chemicals (PFCs), such as perfluorooctanoic acid (PFOA), are environmentally persistent industrial chemicals often found in biosolids. Application of these biosolids to pastures raises concern about accumulation of PFOA in the edible tissues of food animals. Because data on the absorption, distribution, metabolism, and excretion (ADME) of PFOA in cattle were unavailable, a study was conducted to determine pharmacokinetic parameters following a single oral exposure (1 mg/kg body weight of 14C-PFOA) in four Lowline Angus steers. Radiocarbon was quantified in blood, urine and feces for 28 days and in tissues at the time of slaughter (28 d) by liquid scintillation counting (LSC) or by combustion analysis with LSC with confirmation by liquid chromatography-tandem mass spectrometry (LC-MS/MS). 14C-PFOA was completely absorbed and excreted (100.7 +/- 3.3% recovery) in the urine within 9 days of dosing. The plasma elimination half-life was 19.2 +/- 3.3 hrs. No 14C-PFOA-derived radioactivity was detected in edible tissues. Although PFOA was rapidly absorbed, it was also rapidly excreted by steers and did not persist in edible tissues, suggesting beef from cattle exposed to a single dose of PFOA is unlikely to be a major source of exposure to humans.