Contamination and Risk Assessment of Perfluoroalkyl Substances in Surface Water in the Guanzhong Section of the Wei River Basin
The Guanzhong region, traversed by the Wei River Basin, is one of the most industrially, agriculturally, and medically advanced and densely populated areas in Northwest China, has seen increasing attention paid to the pollution of perfluoroalkyl substances (PFASs) in its surface water environment. This study systematically investigated the pollution characteristics of PFASs in the surface water of this region and their ecological and health risks. By optimizing the online solid-phase extraction-liquid chromatography-tandem quadrupole mass spectrometry (Online SPE-LC/MS/MS), efficient detection of 19 PFASs was achieved, with the method detection limits ranging from 0.2 ng·L−1 to 0.3 ng·L−1, linear correlation coefficients all ≥ 0.990, and spiked recoveries between 75.2% and 130.0%. Monitoring data indicated that PFBA, PFPeA, PFHxA and PFOS, short-chain perfluorinated compounds, were the main pollutants in this region, with high detection frequencies and concentrations, but the overall content was lower than that in most areas of China. The concentrations of PFASs in surface water showed significant seasonal variations, with the highest concentrations during the dry season (∑19PFASs:126.1 — 2584.3 ng·L−1), followed by the normal season (∑19PFASs:3.5—3567.6 ng·L−1), and the lowest during the wet season (∑19PFASs:26.3—294.6 ng·L−1). Ecological risk assessment showed that, except for PFDoDA in the dry season, the ecological risk quotient (RQ) of all other PFASs was < 1. Although the water of the Wei River is not used as direct drinking water, health risk assessment indicated that all PFASs posed low risks, with only PFOA and PFOS showing potential risks (HR > 0.1) to adults and children at some sites during dry/normal seasons. This study provides a scientific basis for PFASs pollution control in the Wei River Basin.