Tissue histology and depuration of per- and polyfluoroalkyl substances (PFAS) from dairy cattle with lifetime exposures to PFAS contaminated drinking water and feed

Authors: Lupton, Sara; Smith, David; HOWEY, ERIN - Food Safety Inspection Service (FSIS); PREDGEN, ANN - Food Safety Inspection Service (FSIS); SCHMIDT, CARRIE - Food Safety Inspection Service (FSIS); SCHOLLJEGERDES, ERIC - New Mexico State University; IVEY, SHANNA - New Mexico State University; ESTEBAN, EMILIO - Food Safety Inspection Service (FSIS); JOHNSTON, JOHN - Retired Non ARS Employee

Submitted to: Food Additives & Contaminants. Part A: Chemistry, Analysis, Control, Exposure & Risk Assessment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2024
Publication Date: 1/9/2025
Citation: Lupton, S.J., Smith, D.J., Howey, E.B., Predgen, A.S., Schmidt, C.E., Scholljegerdes, E., Ivey, S., Esteban, E., Johnston, J.J. 2025. Tissue histology and depuration of per- and polyfluoroalkyl substances (PFAS) from dairy cattle with lifetime exposures to PFAS contaminated drinking water and feed. Food Additives & Contaminants. Part A: Chemistry, Analysis, Control, Exposure & Risk Assessment. https://doi.org/10.1080/19440049.2024.2444560.
DOI: https://doi.org/10.1080/19440049.2024.2444560

Interpretive Summary: Poly-and perfluorinated substances (PFAS) are a concern due possible health effects that have been associated with their presence in food and water. In some states, dairy animals contaminated with PFAS via feed and water and milk from the cows could not be marketed. ARS scientists in Fargo, North Dakota characterized the rates of PFAS depletion from milk and edible tissues of cattle sourced from a contaminated farm. Although microscopic evaluation did not reveal tissue abnormalities in exposed animals, low levels of sulfate containing PFAS residues remained in milk and most tissues for 22-weeks after cows were removed from the contaminated farm. In contrast, carboxylate containing PFAS residues did not accumulate in the cattle. Data generated from the study will aid regulatory agencies in determining the relative risks of consuming milk and meat from cattle inadvertently exposed to PFAS.

Technical Abstract: Plasma, milk (lactating animals), and tissue samples were collected from 30 dairy cattle with lifetime exposures to perfluoroalkyl substances (PFAS) removed from a PFAS contaminated farm and provided PFAS-free feed and water. Twenty cattle were slaughtered 2 weeks after removal from the farm and tissues were collected for histological and residue analyses. Milk and/or plasma were collected from all remaining cattle at 2-week intervals and milk samples were collected daily but were analyzed at the same intervals as plasma samples. The remaining cattle were slaughtered 20 and 22 weeks after the initial set of 20 animals were slaughtered. While many incidental and normal background findings were noted on histological evaluation, no consistent histological finding was associated with PFAS exposure. Perfluoroalkyl carboxylic acids (PFCA) and perfluoro butane sulfonic acid (PFBS) were not generally detected in milk, plasma, and tissues, but perfluoroalkyl sulfonic acids (PFSA) were quantifiable throughout the 22-week withdrawal period in most matrices. Estimated plasma half-lives of perfluorohexane sulfonic acid (PFHxS), perfluoroheptane sulfonic acid (PFHpS), linear perfluorooctane sulfonic acid (L-PFOS), perfluoro-3-methyl heptanesulfonate(3Me-PFOS) and perfluoro-6-methyl heptanesulfonate (6Me-PFOS) ranged from 4 to 10 weeks, but the estimates were associated with large confidence intervals. Across animal status (heifer, lactating, dry) natural log transformed (Ln) plasma residues of PFHxS and L-PFOS were generally well correlated with Ln transformed PFHxS and L-PFOS residues in lung, muscle, liver, and kidney (R2, 0.7572 to 0.9394) whereas the strongest relationships of Ln-transformed L-PFOS residues among tissues were between lung and liver, kidney, and muscle (R2, 0.8287 to 0.9138).