The occurrence and distributions of per- and polyfluoroalkyl substances (PFAS) in groundwater after a PFAS leakage incident in 2018.

Per- and polyfluoroalkyl substances (PFAS) concentrations of groundwater in three cities of the Nakdong River Basin in South Korea were quantified to investigate PFAS contamination and the effect of PFAS leakage incident that occurred in the study area in 2018. Groundwater PFASs concentration ranged from non-detectable (N.D.) to 36.9 ng/L (mean 14.1 ng/L), in which, perfluorooctanoic acid (PFOA), perfluorohexanoic acid (PFHxA), perfluoropentanoic acid (PFPeA), and perfluorohexane sulfonate (PFHxS) were commonly observed. Compared to long-chain (C ≥ 8) PFAS, short-chain (<C8) PFAS are more commonly detected in groundwater. Statistical differences were found between the groundwater obtained from different land use. PFAS detected in groundwater from industrial land use were significant different (p<0.01) than other land usages. Spatial difference of PFAS concentrations and distributions in groundwater were also found. PFAS concentrations in groundwater at the furthest downstream area (mean 26.4 ng/L) were the highest followed by the middle reaches (mean 16.2 ng/L), and the upstream area (mean 4.3 ng/L). PFHxS, which was detected dominantly in the middle reach areas, contributed 51% of the total PFAS concentration, but was not detected in the upstream area. There was no health risk by drinking groundwater but found the effect of PFHxS leakage incident on groundwater.