Trophic magnification and distribution of PFAS in an aqueous film forming foam-affected aquatic food web

Robust characterizations of how per- and polyfluoroalkyl substances (PFAS) behave in complex aquatic food webs are needed to better understand the ecological risk PFAS pose. We sampled a range of producers and consumers (macroinvertebrates, amphibian, fish, and reptiles) in a wetland affected by PFAS associated with the use of aqueous film forming foams (AFFFs). Thirty PFAS and δ15N in the whole bodies of biota were quantified to characterize PFAS bioaccumulation in the aquatic food web and assess individual PFAS potential for trophic magnification. Trophic position explained substantial variation in total PFAS bioaccumulation across all aquatic consumers (R2adj = 0.66) and within broad taxonomic groups, including invertebrates (R2adj = 0.53), amphibians (R2adj = 0.29), and fish (R2adj = 0.38). Eight PFAS had trophic magnification factors in the 2.4-11 range, indicating that diet contributes substantially to PFAS exposure and accumulation in aquatic organisms. Specific accumulation profiles appeared more related to taxonomic groupings than trophic position. These patterns indicate consumers can be exposed to a variety of PFAS that they do not bioaccumulate, many of which have limited toxicity data. Our results highlight the complexities and data gaps associated with the ecological risk PFAS may pose at AFFF-affected sites.