Integrated source apportionment and ecological risk assessment of PFASs in sediments: Insights from a case study from an urban river basin in China

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are persistent organic pollutants widely detected in aquatic environments, posing increasing environmental and health concerns. This study investigated the occurrence, spatial distribution, potential ecological risks, and sources of PFASs in surface sediments from the Qinhuai River Basin in China. Of the 23 target PFASs, 19 were detected, with total concentrations ranging from 0.05 ng/g to 116.0 ng/g. Perfluorobutanoic acid (PFBA) and perfluorooctanoic acid (PFOA) were the dominant compounds. Hierarchical cluster analysis revealed distinct spatial patterns of PFAS contamination, with generally higher concentrations in the eastern region than in the west, notably elevated levels at sites E2 and F1, and the lowest at sites C1 through C4. Ecological risk was assessed using the risk quotient approach as a screening-level tool. The results indicated that a limited number of long-chain PFASs, including PFOA, perfluorooctane sulfonate (PFOS), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), and perfluorododecanoic acid (PFDoDA), frequently exceeded their predicted no-effect concentrations, suggesting a relatively high likelihood of ecological concern, whereas most other PFASs showed low probabilities of exceedance under current conditions. Positive matrix factorization identified six main sources of PFASs: household consumption (75.0%), agricultural runoff (16.2%), firefighting-related activities (5.3%), wastewater treatment plants (1.8%), coating and textile industries (1.3%), and metal-related industries (0.3%). These findings highlight the dominant role of regional industrial structures in shaping PFAS contamination patterns in sediments.