Distribution and Risk Assessment of Per- and Polyfluoroalkyl Substances from Source Water to Tap Water in the Hubei Section of the Yangtze River Mainstream
Per- and polyfluoroalkyl substances (PFAS) are emerging contaminants of concern in China, and drinking water is a major exposure pathway. This study investigated 17 PFAS in surface water from 12 drinking water sources along the Hubei section of the Yangtze River mainstream during dry, normal, and wet seasons. Total PFAS concentrations ranged from 10.84 to 41.05 ng/L (dry), nd to 62.60 ng/L (normal), and 6.77 to 29.00 ng/L (wet). Predominant compounds were PFBS, PFOA, PFHxA, PFBA, and PFOS. Lake-type sources exhibited significantly higher concentrations than river-type sources, and dry and normal seasons showed higher levels than wet season. Compared to other Chinese sources, PFAS levels in Hubei were moderate, with fluorochemical plant inputs and population density as likely influencing factors. Ecological and health risk assessments indicated acceptable risks. In four selected water supply systems, PFAS distribution from source to tap was examined; PFOA, PFBA, PFHxA, and PFBS were dominant, and secondary water supply did not significantly introduce or remove PFAS. Health risks from tap water were within acceptable limits.