An exploratory analysis of poly- and per-fluoroalkyl substances in pet food packaging from the United States

Abstract

Poly- and per-fluoroalkyl substances (PFAS) were reported to be used in food packaging to impart water and oil repellency. Little is known, however, with regard to the occurrence of PFAS in pet food packaging. In this study, 37 pet food packaging and 11 pet foods were analyzed for the determination of 13 perfluoroalkyl acids (PFAA), including nine perfluoroalkyl carboxylic acids (PFCA; C 4 - C 12 ) and four perfluoroalkyl sulfonic acids (PFSA; C 4 - C 10 ). Furthermore, samples were extracted in organic solvents (methanol and ethyl acetate) and an aliquot of the extract was analyzed using total oxidizable precursor (TOP) assay to determine the occurrence of PFAS precursors that may be present in packaging. PFSA concentrations were below their respective limits of detection. Plastic food packaging samples contained ∑ PFCA (sum of 9 PFCAs) concentrations an order of magnitude higher (range: <LOD-60.0 ng/g; mean: 11.8 ng/g), following oxidation of extracts by the TOP assay, than those measured prior to oxidation (range: <LOD-10.3 ng/g; mean: 1.28 ng/g). Similarly, pet food contained approximately an order of magnitude higher ∑ PFCA concentrations (range: 0.600–14.3 ng/g; mean: 5.71 ng/g) following oxidation than those measured prior to oxidation (range: <LOD-3.67 ng/g; mean: 0.89 ng/g). Higher ∑ PFCA concentrations following the TOP assay suggested the occurrence of PFAA precursors in food packaging. Fluorotelomer alcohols were suspected to contribute to higher PFCA concentrations measured following the oxidation of extracts of food packaging. • Perfluoroalkyl substances were measured in pet packaging and pet food. • Total oxidizable precursor (TOP) assay was applied in the analysis. • ∑ PFCAs concentrations in packaging before and after the TOP assay were 1.99 and 11.0 ng/g, respectively. • Precursors that were oxidized to PFBA were found in pet food and packaging.