PFAS on the U.S. Department of Energy’s Savannah River Site: spatial distribution, bioavailability, co-occurrence with metals, and potential biomagnification

Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent contaminants with the potential to adversely affect ecosystem health. Characterizing the spatial dynamics, bioavailability, and potential for biomagnification within exposed ecosystems is necessary for gauging potential risk to wildlife and humans. In this study, we analyzed PFAS concentrations in surface waters, sediments, and biota collected from 30 locations across watersheds on the U.S. Department of Energy's Savannah River Site (SRS). The 800 km2 SRS was designated the nation's first National Environmental Research Park in 1972, and we contextualize measured PFAS concentrations within a rich history of environmental and ecotoxicological research. Concentrations of total PFAS ranged from nondetect to 2,226 ng/L in water, 65 ng/g in sediment, and 158 ng/g in mosquitofish. Per- and polyfluoroalkyl substance concentrations in fish were elevated despite relatively low concentrations in water and sediment at some locations, demonstrating the importance of including biota for bioavailability assessments. Co-occurrence analyses of PFAS with 22 metals/metalloids revealed strong positive correlations between PFAS and metal concentrations in sediment. At the landscape scale, we identify linkages between PFAS concentrations and watershed landcover dynamics, including watershed size, proportion of watershed development, and sediment composition. Additionally, we examine PFAS concentrations and stable isotope signatures in an affected stream community and find that sum PFAS, long-chain perfluoroalkyl carboxylic acid (C8 up to C14), perfluorooctane sulfonic acid, and 7:3 fluorotelomer carboxylic acid concentrations were positively related to nitrogen isotope signatures, indicating their potential biomagnification. Collectively, our study characterizes initial environmental and biological PFAS levels on the SRS within stream ecosystems and will serve as a guide for future ecotoxicological studies and risk assessments.