Length-specific occurrence and profile of perfluoroalkyl acids (PFAAs) in animal protein feeds

Animal protein supplement feeds (APFs) are susceptible to perfluoroalkyl acids (PFAAs) and could be the main sources for raised animals, thereafter causing further human exposure through the farm-to-fork pathway. However, the occurrence of PFAAs has been rarely evaluated in various APFs, especially for emerging short-chain PFAAs. In the present study, we collected the most prevalent APFs (blood meal, meat meal, feather meal, soybean meal and DDGS) and found that Σ₁₆PFAAs ranged from undetectable to 37.1 ng/g dry weight (dw) (average: 7.23 ng/g dw). Blood meal contained the highest PFAA levels, and results revealed that some terrestrial-derived APFs might be present at levels on par with the marine-derived feed. Animal-derived APFs (mean 10.9 ng/g dw) possessed higher ∑PFAAs than plant-derived APFs (0.75 ng/g dw). Length-specific PFAA profiles were specified between terrestrial-origin and marine-origin feeds in addition to animal-derived and plant-derived feeds. Short-chain PFAAs (PFBA, PFBS and PFHxS) were primarily found in blood meal, meat meal, soybean meal and DDGS, while the long-chain counterparts dominated in feather meal. It is of great concern that feed exposure to emerging contaminants has not drawn enough attention.