Spatial distribution, seasonal variation and risks of legacy and emerging per- and polyfluoroalkyl substances in urban surface water in Beijing, China

In the current study, we investigated the occurrence, spatial distribution and seasonal variation of per- and polyfluoroalkyl substances (PFASs), including one group of emerging PFASs, the chlorinated polyfluoroalkyl ether sulfonic acids (Cl-PFESAs), in urban surface water (river and lake) samples from October 2013 to September 2014 (except during the frozen period) in Beijing, China. Perfluorobutanoic acid (PFBA) and perfluoropentanoic acid (PFPeA) were the dominant compounds, with average concentrations of 12.79 and 9.90 ng/L, respectively. For Cl-PFESAs, only C8 Cl-PFESA could be detected, and its concentration ranged from