Distribution, temporal variation, and treatment of per- and polyfluoroalkyl substances (PFAS) in urban stormwater runoff

Per- and polyfluoroalkyl substances (PFAS) are emerging contaminants known for their persistence and potential health risks. Stormwater runoff serves as a major pathway for contaminant transport into aquatic ecosystems, yet data on the occurrence, distribution, and transport of PFAS via stormwater runoff remain limited. This study revealed PFAS in stormwater runoff from high- and low-traffic areas in Trenton and Glassboro, NJ, during precipitation events from February to August 2024, and explored the removal of PFAS by drinking water treatment residuals (WTRs). Results showed that perfluorooctanesulfonic acid (PFOS), perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), and perfluoropentanoic acid (PFPeA) were the most prevalent PFAS compounds in the stormwater runoff in both locations. PFAS concentrations were significantly higher in high-traffic than low-traffic areas in both cities, with Trenton showing higher levels than Glassboro, reaching 444 ng/L and 233 ng/L, respectively. PFAS levels were highest at rainfall onset and gradually declined as precipitation continued. Adsorption studies using Al-WTR for representative legacy and emerging PFAS showed a maximum adsorption capacity of 121 μg/g for PFOS, followed by PFNA (101.5 μg/g), PFOA (96.3 μg/g), HFPO-DA (76 μg/g), PFBS (67 μg/g), and PFHxS (66.7 μg/g). These findings provide critical insights into PFAS distribution, transport, and removal in urban stormwater runoff, emphasizing the roles of traffic and stormwater dynamics in PFAS dispersal.