The first survey of legacy and emerging per- and polyfluoroalkyl substances (PFAS) in Hulun Lake, China: Occurrence, sources, and environmental impacts

Many per- and poly-fluoroalkyl substances (PFAS) studies in environmental media have been conducted in heavily industrialized and densely populated areas. However, there has been limited research on legacy and emerging PFAS contamination in cold and arid regions. In the present study, we investigated the concentrations of 30 PFAS compounds in the surface water and sediment of Hulun Lake and its inflowing rivers. The main components in water were short chain perfluoroalkyl carboxylic acids (PFCAs) in both Hulun Lake (33.57 %) and its inflowing rivers (30.47 %). However, long chain perfluoroalkane sulfonates (PFSAs) and long chain PFCAs accounted for more than half of the total PFAS content in sediment. Total PFAS concentrations (∑₃₀PFAS) ranged from 3.67 to 8.84 ng/L in water, and 0.97–1.73 μg/kg in sediment. Significant spatial differences were apparent between Hulun Lake and its inflowing rivers in both water and sediment samples. Source apportionment revealed that wastewater, aqueous film forming foams, textiles and paper-based food packaging, and paper products and cosmetics were the primary sources of PFAS. The partitioning coefficients of PFCAs were dependent on the carbon chain length. Temperature, conductivity, pH, salinity, chemical oxygen demand, total phosphorus (TP), total nitrogen (TN), As, and oxidation-reduction potential were the main influencing factors in water. Heavy metals (Co, Pb, Cu, Ni, Hg, Cd, and As), TP, salinity, and pH were positively correlated with the PFAS concentration in sediment. Furthermore, Hailar River contributed the majority (99.74 %, ∼15.05 kg/year) of the PFAS mass flux. This is the first study showing PFAS contamination in Hulun Lake and the results suggest that long term monitoring is needed for the effective control of PFAS pollution in this typical cold and arid region of China.