Pollution characteristics, source analysis and risk assessment of perfluoroalkyl and polyfluoroalkyl substances of Kui River

To investigate the pollution distribution characteristics and ecological risk levels of per- and polyfluoroalkyl substances (PFAS) in the surface water of the Kui River, this study tested 17 PFAS in the surface water and analyzed their pollution levels in the local aquatic environment. Results showed PFAS were ubiquitous in the Kui River, with ΣPFAS concentrations ranging from 241.83 to 700.09 ng·L-1. The main pollutants were perfluorobutyric acid (PFBA), perfluorohexanoic acid (PFHxA), and perfluorooctanoic acid (PFOA), with average concentrations of 124.62, 127.26, and 188.47 ng·L-1, respectively. Per- and polyfluoroalkyl substances (PFAS) composition had distinct seasonal variations: PFBA dominated in the wet season, while PFOA prevailed in the dry season. Principal component analysis indicated PFAS pollution mainly originated from food packaging, surfactant production, plastics, and metal plating/textiles. Ecological risk assessment showed most PFAS posed low risks; only PFOA had low risk at all dry-season sampling sites, and mixture Risk Quotient (RQmix) posed a general low-level risk. Health risk assessment found Hazard Quotient (HQ) values of seven PFAS for all age groups ranged from 1.36E-4 to 0.247. PFOA exposure had HQ > 0.1 (low hazard), while the other six showed no significant hazard. However, HQmix exceeded 0.1 for all four age groups, indicating adverse health effects. Future attention should focus on the management of dynamic PFAS sources and the combined risk posed by PFAS mixtures in the Kui River.