Fate of [14C] polyethylene terephthalate nanoparticles after oral dosing to lactating sheep

Authors: Shelver, Weilin; McGarvey, Amy; Billey, Lloyd; Singh, Anuradha

Submitted to: International Chemical Congress of Pacific Basin Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 6/13/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Polyethylene terephthalate (PET) is a plastic often produced for single-use packaging materials such as water bottles. After weathering and degradation, PET becomes one of the most frequently detected microplastics/nanoplastics (MP) in food and the environment. Data describing the absorption, distribution, and excretion of MP in terrestrial food animals is limited. In this study, six lactating sheep were orally administered a single dose of 980 µCi [14C] PET nanoparticles (230 - 510 nm; 2.67 ± 0.19 mg/kg body weight). Three sheep each were sacrificed after 24- and 72-h withdrawal periods and the fate of [14C] in excreta, milk, and tissues was measured. Total recoveries of radioactivity in milk and urine were < 0.003% and < 0.04%, respectively, with [14C] activities remaining above that in control matrices for up to 72 h after dosing. Radiocarbon quantifiable in mammary glands (< 0.003% recovery) of sheep 24 h after dosing, but not after 72 h. [14C] activities were quantifiable in abomasum, omasum, and rumen as well as in adipose tissue in animals harvested 24 h after dosing, but quantifiable [14C] PET was not present in skeletal muscle. The majority of the [14C] activity was present in feces. These data suggest that ruminant exposure to [14C] PET nanoparticles is unlikely to pose food safety risks, and that most dietary PET nanoparticles would return to the environment.