Contamination characteristics and health risk assessment of perfluorinated compounds in the Wangyu River

Water diversion projects, while alleviating water scarcity, may become important conduits for the trans-basin transport of perfluorinated and polyfluoroalkyl compounds (PFASs). The pollution characteristics of PFASs in the water of the Wangyu River, the primary conveyance canal for the Yangtze River to Lake Taihu diversion project, remain unclear. In this study, the pollution characteristics of 23 PFASs in water bodies and their ecological health effects were systematically analyzed in Wangyu River. The results showed that significant spatial differences in ΣPFASs concentrations were observed, and influenced by point source emissions from the industrial park, the concentration showed a gradient decreasing trend from the upstream industrial zone to the inlet of Lake Taihu. Among them, the industrial park section was dominated by the novel alternative hexafluoropropylene oxide dimer (HFPO-DA) and short-chain perfluorohexanoic acid (PFHxA), while the middle and downstream regions were dominated by the traditional perfluorocarboxylic acids perfluorobutyric acid (PFBA) and perfluorooctanoic acid (PFOA). Spearman correlation analysis and principal component analysis revealed that the characteristic pollutants (HFPO-DA, PFHxA) in the industrial park section were significantly separated from those in the middle and lower reaches of the river (the cumulative variance contribution rate of the first two principal components reached 90.22%), which indicated that the two had different sources, and the PFASs in the industrial park did not cause direct significant pollution to Lake Taihu through Wangyu River during the non-diversion period. The multidimensional risk assessment found that the RQ values of the five PFASs were below 0.01, which were at acceptable risk levels, except for PFOA and PFOS, which were at moderate risk to algae and fish. The health exposure assessment showed that there was no health risk of PFASs in drinking water intake of adults and children in the Lake Taihu inlet section, however, the daily intake of children via drinking water route (11.25 - 11.36 ng·kg^-1·d^-1) was higher than that of adults (8.32 - 8.39 ng·kg^-1·d^-1). In the future, it is necessary to strengthen the continuous monitoring of PFASs and to combine multiple pathways to assess the risk of exposure to PFASs in the population.