Occurrence and human exposure assessment of PFAS in river and groundwater around a closed fluorochemical plant in China

Studies have demonstrated that point source emissions constitute the main direct source of PFASs in water. However, if production/usage and emission from a specific point are stopped, does the point source still present a threat to surrounding waters? In this study, the occurrence and potential human exposure to 17 PFASs in the surrounding ambient river and ground/drinking water within a 13 km around the facility were assessed. Of the 17 PFASs analyzed, 11 were frequently detected in river and groundwater samples, with perfluorobutane sulfonate (PFBS) (36.8-11462.9 ng/L), perfluorobutyric acid (PFBA) (below the detection limit (BDL)-4789.8 ng/L) and perfluorohexane sulfonate (PFHxS) (3.3-3549.0 ng/L) exhibiting the highest concentrations. Prevalence of short-chain PFASs was observed in both river and groundwater. The spatial distribution pattern showed that locations near the facility exhibited higher PFASs concentrations. The seasonal distribution pattern indicated that the PFASs concentration in river water during the wet season was higher than that during the dry season. However, the seasonal distribution in groundwater was unexpectedly the opposite to that in river water. Nevertheless, the major health risk of PFASs is primarily attributed to the presence of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) with maximum hazard quotients of 6.9 × 10² and 1.0 × 10³ and 2.4 and 3.6 for adults and toddlers, respectively. Thus, the potential threat of the closed fluorochemical manufacturing plant to the surrounding waters cannot be ignored.