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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Food Animal Metabolism Research » Research » Publications at this Location » Publication #414731
Research Project: Detection and Fate of Environmental Chemical and Biological Residues and their Impact on the Food Supply

Location: Food Animal Metabolism Research

Title: Disposition of [14C]-polystyrene microplastics after oral administration to lactating sheep

Author
item Shelver, Weilin
item McGarvey, Amy
item Billey, Lloyd

Submitted to: Food Additives & Contaminants. Part A: Chemistry, Analysis, Control, Exposure & Risk Assessment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Microplastics (MP) are environmental contaminants that have been increasingly found in feed, food, and water used for human and/or animal consumption. Only limited information is available on the fate of MP in domestic food animals. In this study, radiolabeled polystyrene MP were dosed to sheep and the fate of MP was monitored. Low but measurable quantities of radiotracer were present in blood, milk, and urine throughout the 72-hour study, but most of the MP were not absorbed and were excreted in feces. The results suggest that polystyrene microparticles are poorly absorbed by ruminants and that ingested MP return to the environment through fecal excretion.

Technical Abstract: Microplastics have become a ubiquitous contaminant, but their fate in food animals is largely unknown. In this study, [14C]-polystyrene microplastic (PS-MP) particles were orally dosed to lactating sheep to evaluate absorption and disposition. Elimination of the [14C]-PS-MP was predominately through feces with fecal radioactivity peaking at 24-hour post-dosing but continuing to be present throughout the entire 72-hour study period. Only a small fraction (= 1%) of the dosed [14C]-PS-MP were present in blood, milk, and urine. Pharmacokinetic analysis of blood plasma radioactivity, using non-compartment modeling, indicated rapid absorption (T1/2 0.4 to 3 hours) with slow elimination (T1/2 37 to 48 hours). Radioactivity in milk and urine had similar elimination patterns with radiocarbon activities peaking 24-hour post-dosing with detectable elimination throughout the 72-hour study period. No radioactivity was quantifiable in tissues at 72-hour withdrawal.