Poly- and perfluoroalkyl substances in a drinking water treatment plant in the Yangtze River Delta of China: Temporal trend, removal and human health risk

Poly- and perfluorinated substances (PFASs) have been found ubiquitously all over the world in drinking water, thus attracting concern of public opinion and regulators. The present study was carried out in a drinking water treatment plant (DWTP) located in the city of Changzhou (China), near the Yangtze River Delta. 31 PFASs concentrations were analyzed in the DWTP process water flows, as well as in its upstream source water (Yangtze River and Desheng River) and downstream public supply water. 13 PFASs were detected in source and drinking water with total concentration of 25–38 ng/L, which were higher for Yangtze River than Desheng River. The predominant contaminants were perfluorobutanesulfonate, perfluorooctanoic acid and perfluorobutanoic acid. In addition, HFPO-TA was identified for the first time in Yangtze River. Data indicate that PFASs discharge in Yangtze River is remarkable, with a mass flow in the wet season (i.e. summer) up to 83 kg/d. However, oxidizable precursors (quantified by total oxidizable precursor assay) were 21–88% of total PFASs, constituted mainly by short-chain homologues. Taking these precursors into account, an opposite picture is observed: Desheng River had higher concentration of total PFASs than Yangtze River. Results for the DWTP indicate that PFASs concentration was not affected by conventional treatment processes and remained unchanged also in the downstream public water supply pipelines. More importantly, granular activated carbon removed effectively only sulfonated and carboxylated congeners, but was inefficacious with oxidizable precursors. The present study demonstrates that, despite implementation of treatment by granular activated carbon, there is still a risk for citizens deriving from drinking water of Yangtze River. [Display omitted] •Thirteen of 31 PFASs (24–42 ng/L) were found in Yangtze River, DWTP and drinking water of Changzhou, China.•No concentration changed alone the DWTP treatment processes except GAC, as well as the public water supply pipelines.•Significant increments appeared after persulfate oxidization, especially in the Desheng River (Cmax = 73 ng/L).•The RQ of PFASs in Drinking water in Changzhou was up to 1.7.