Occurrence, Distribution and Ecological Risk of PFASs in Water and Sediment from the Upper Xiaoqing River, Shandong Province, China

Per- and polyfluoroalkyl substances (PFASs) have received worldwide attention due to their persistence, bioaccumulative potential, toxicity, and long-range transport capabilities. In this study, the pollution characteristics and ecological risk of 17 PFASs in both water and sediments from the upper Xiaoqing River were investigated. The 17 PFASs had concentrations ranging from 43.51 to 343.06 ng/L (average: 85.53 ± 43.78 ng/L) in water and 1.21 to 8.14 ng/g (2.94 ± 1.47 ng/g) in sediments, with the highest-level site near the fluoropolymer-producing facility at the river entrance. The lowest concentration, with a clean section, occurred at the river source. Perfluorooctanoic acid (PFOA) was the most prevalent PFAS, followed by perfluorohexanoic acid (PFHxA) and perfluoropentanoic acid (PFBS) in water. PFOA and short-chain PFASs contributed to the majority (76.22–92.25%; mean: 86.46%) in water. In sediments, PFOA was still the predominant PFAS at most sites, contributing 33.84 to 38.65%. The contribution of long-chain PFASs accounted for the majority (>70%) of the total concentrations of the PFASs analyzed in sediments. The proportion of PFOA in the two studied media was six times higher in water (61.27%) than in sediment (10.70%) from fluoropolymer-producing facility discharge. Generally, the lgKd of the PFASs increased with more perfluorinated carbon atoms, indicating that long-chain PFASs were easily adsorbed by sediments due to the high hydrophobic properties. For the same carbon number, the lgKd value of PFSA was higher than that of PFCA, excluding C4 PFAS (PFBS). The risk quotient (RQ) of single-compound PFASs in this study was significantly below 0.1, indicating a relatively low ecological risk. The RQ value of PFOA around the fluoropolymer-producing facility in both water and sediment was higher than that at other points. The cumulative risk of PFOA exposure cannot be disregarded.