Trophic Magnification of Short-Chain Per- and Polyfluoroalkyl Substances in a Terrestrial Food Chain from the Tibetan Plateau

While there is a lack of information about the trophic transfer of short-chain per- and polyfluoroalkyl substances (PFASs) in the terrestrial ecosystem, this study focused on the occurrence and trophic transfer of both legacy and short-chain PFASs in a terrestrial food chain composed of the plants, plateau pikas, and eagles of the Tibetan Plateau. Total PFAS concentrations were in the range of 0.130–1.507, 0.406–1.085, 0.601–8.293, and 5.021–76.482 ng/g dw in soils, plants, pika muscles, and eagle muscles, respectively, among which perfluorooctanesulfonic acid (PFOS) and perfluorobutanoic acid (PFBA) were predominant in all sample types. Levels of PFASs in eagle feathers were significantly correlated with those in eagle muscles (r = 0.73), implying feathers could be used as an indicator of exposure of raptors to PFASs. Trophic magnification factors of PFOS (5.75), perfluorohexanesulfonic acid (2.43), C₁₀–C₁₂ perfluorocarboxylic acids (1.84–4.65), PFBA (5.11), and perfluorobutanesulfonic acid (5.96) along the plant–pika–eagle food chain were all significantly greater than 1. The short-chain PFASs may be biomagnified in air-breathing animals because of the nonvolatility of their charged forms and recalcitrance (not biotransformed). The results suggest that the ecological risks of these short-chain substitutions warrant further investigation.