Exposure to Industrial Wastewater Containing Elevated Per- and Polyfluoroalkyl Substances (PFAS) Alters a Riparian Insectivore Microbiome

Abstract Per- and polyfluoroalkyl substances (PFAS) are widespread contaminants of global concern due to their persistence, biomagnification potential in aquatic environments, and mounting evidence of toxic effects. Emerging experimental evidence indicates that chronic exposure to PFAS can alter the composition and function of a host organism’s microbiome. To test this in the field, we analyzed microbiomes of larval and adult aquatic insects, along with riparian spiders, from a stream receiving industrial wastewater with elevated concentrations of PFAS from a food processing facility. Spiders consume substantial aquatic insect biomass globally and are frequently used as biosentinels for tracking aquatic-derived contamination in riparian ecosystems. Here, we found that larval and adult insects and spiders had 5-, 1.4- and 5-fold higher concentrations, respectively, of PFAS downstream than upstream of the outfall. Downstream spider microbiomes had unique community structure, higher diversity, and increased predicted representation of xenobiotic degradation and metabolism gene functions compared to paired spider microbiomes upstream of the wastewater outfall. Given the abundance and distribution of both PFAS and spiders globally, our findings provide insight into how host microbiomes may respond to ubiquitous, chronic wastewater mixtures with elevated PFAS and provide insight into evaluating PFAS exposure across aquatic-riparian ecosystems.