Per- and Polyfluoroalkyl Substance (PFAS) Occurrence in Gunpowder River Watershed in Maryland United States

Per- and polyfluoroalkyl substances (PFASs) represent a group of persistent environmental contaminants with known adverse health effects. This study assessed the presence and concentrations of PFASs in surface water across various locations along the Gunpowder River Watershed in Maryland, United States. Gunpowder RIVERKEEPER® a 501(c)(3) nonprofit collected eleven surface water grab samples from the Gunpowder River Watershed for the study, including both drinking water sources and non-drinking tributaries. Of the 55 PFASs analyzed, multiple compounds, including PFOS, PFOA, PFBS, PFHxA, PFPeA, and PFHpA, were detected above reporting limits at all sampled locations. Total PFAS concentrations varied substantially across the watershed, ranging from 2.1 to 21.3 ng/L in drinking water source tributaries and 6.6–18.4 ng/L in non-drinking tributaries. Several sites exhibited PFOS and PFOA concentrations exceeding the 2022 U.S. EPA interim lifetime health advisory levels, indicating potential risk to downstream communities relying on these water sources. Short-chain PFASs (C ≤ 7) were more abundant than long-chain PFASs, reflecting their greater mobility and persistence in surface waters. These findings demonstrate watershed-wide PFAS contamination and highlight the potential for trophic transfer and bioaccumulation in fish species in these tributaries and subsequent human exposure. Continued monitoring, regulation, and remediation efforts are required to mitigate PFAS contamination and safeguard public health in vulnerable ecosystems and populations. Further research is needed to better understand the extent of PFAS exposure, associated health risks, and effective strategies for prevention and management.