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

Food Additives & Contaminants Part A 2024 10 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count.
Weilin L. Shelver, Amy M. McGarvey, Lloyd O. Billey

Summary

When lactating sheep were fed radioactively labeled polystyrene microplastics, most passed through in feces, but a small fraction (up to 1%) entered the blood, milk, and urine. The microplastics were absorbed quickly but eliminated slowly from the body, with detectable levels persisting throughout the 72-hour study. This is significant because it shows microplastics can transfer into animal milk, meaning dairy products could be a pathway for human microplastic exposure.

Polymers

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 their absorption and disposition. Elimination of the [14C]-PS-MP was predominately through faeces with faecal radioactivity peaking at 24 h post-dosing but continuing to be present throughout the entire 72 h study period. Only a small fraction (≤ 1%) of the dosed [14C]-PS-MP was 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 h) with slow elimination (T1/2 37 to 48 h). Radioactivity in milk and urine had similar elimination patterns with radiocarbon activities peaking 24 h post-dosing with detectable elimination throughout the 72 h study period. No radioactivity was quantifiable in tissues at the 72 h withdrawal period.

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