Simulating transport, flux, and ecological risk of perfluorooctanoate in a river affected by a major fluorochemical manufacturer in northern China.

Perfluoroalkyl acids (PFAAs) have been widely detected and pose potential risks to both human and ecosystem health. Since the probation of perfluorooctane sulfonate (PFOS) by the Stockholm Convention, perfluorooctanoate (PFOA) has frequently been used as a chemical intermediate and processing aid. Owing to a lack of effective treatment technologies for PFOA, surrounding environments have been highly affected. Previous studies by our group have reported elevated PFOA levels in the Xiaoqing River, which receives sewage from a major fluorochemical manufacturer in northern China. To further explore the transport, flux, and ecological risk of the perfluorooctanoate in the river, this study conducted a 2-year sampling campaign of surface water from 2014 to 2015. An extremely high PFOA concentration (mean: 62.3 μg L-1) was observed for the Xiaoqing River in comparison with other studies. The highest average concentration and flux of PFOA were recorded in the autumn and summer, respectively. With data on selected hydrological parameters and cross-sections, PFOA concentrations were modeled using DHI MIKE 11. To explore the current loads and environmental capacity of PFOA, two scenarios (i.e., emissions based on observed concentrations and on the predicted no-effects concentration, PNEC) were set. The simulation results based on observed data showed that PFOA loads in the Xiaoqing River were 11.4 t in 2014, and 12.5 t in 2015. Based on the PNEC, the environmental carrying capacity of PFOA was estimated to be 13.9 t in 2014, and 13.8 t in 2015. The current loads of PFOA were found to approach the maximum environmental carrying capacity. Relatively high risks around both the fluorine industrial park (FIP) and estuary area were identified. In comparison with other suggested guidelines, threats to the ecological status of the river would be severe, which suggests that stringent management and emission criteria are needed for this industry.