Occurrence, distribution, and ecological risks of per- and polyfluoroalkyl substances (PFASs) in the surface water of Caohai wetland, Guizhou Province, China

Abstract The Caohai Wetland is located in a region of karst within the Yunnan-Guizhou Plateau, and serves as an important nature reserve for migratory birds. It is therefore of considerable ecological value in China. The presence and concentration of per- and polyfluoroalkyl substances (PFASs) in the wetland were unknown prior to this investigation. This study documents the occurrence, distribution, and ecological risks of 16 PFASs in the Caohai Wetland. The analysis showed that 11 PFASs were widely present in the Caohai Wetland; total concentrations (defined as the concentration of the total of all studied PFASs, ΣPFASs) ranged from 1.78 ng/L to 112.21 ng/L (mean 19.43 ng/L). Perfluorobutanoic acid (PFBA), perfluorooctanoic acid (PFOA) and potassium perfluorobutanesulfonate (PFBS) were the dominant forms in surface water, contributing 48.12%, 14.61%, and 11.59% to the total PFASs burden, respectively. Chlorinated polyfluoroalkyl ether sulfonic acid (F-53B) was also detected frequently and occurred at relatively high concentrations (0.14–1.48 ng/L, mean 0.48 ng/L). In the absence of point sources, high PFASs concentrations occurred inside a nearby town, resulting from anthropogenic activities. Risk assessment revealed that both individual and combined PFASs pose a relatively low risk to aquatic organisms at the present time. However, long-term monitoring of PFASs in the Caohai Wetland is needed given the potential of PFASs to be biomagnified and the extremely important ecological value of the Caohai Wetland.