Per- and polyfluoroalkyl substances (PFAS) are widespread contaminants in aquatic ecosystems, where they bioaccumulate and trophically transfer through food webs. We derived an ecosystem-scale model assessing Σ12PFAS partitioning, bioaccumulation by larval aquatic insects, bioamplification by adult aquatic insects, and trophic transfer from aquatic insects to riparian spiders using data collected across five streams in a mildly impacted watershed. Partitioning involved the greatest PFAS enrichments (range in posterior median log10 kd values = 1.5-2.1), with lesser concentration increases from particulates to larval aquatic insects and from larval to adult aquatic insects, and Σ12PFAS concentration decreases from adult aquatic insects to spiders. Among the 12 compounds, PFOS had the largest proportional contribution to Σ12PFAS concentrations for all sample types, with consistently increasing concentrations from surface water to adult aquatic insects. Σ12PFAS concentrations (5.4-51 ppb wet weight), body burdens (0.44-5.2 ng per individual), and bioamplification factors (0.15-4.9) differed considerably among five common aquatic insect taxa. This study presents a robust modeling framework for PFAS trophodynamics and offers insights into the biological controls that contribute to the context dependency of PFAS at the interfaces of aquatic and terrestrial food webs.
Campbell et al. (Fri,) studied this question.