Occurrence ofPer- and Polyfluoroalkyl Substances(PFAS) in Potable Groundwater near Military Bases in South Korea

Aqueous film-forming foam (AFFF) has been identified as a major source of per- and polyfluoroalkyl substances (PFAS) contamination in the environment. We assessed the occurrence of major PFAS and their substitutes in the groundwater surrounding military bases in South Korea. Groundwater samples were collected from publicly accessible wells near four U.S. military installations in three cities between June and October 2023. In the wells closer to the military bases, more elevated PFAS levels were detected following the flow directions. The highest concentrations of PFOA (maximum of 125 ng/L), PFOS (maximum of 103.7 ng/L), and PFHxS (maximum of 127.8 ng/L) were observed in the wells near camps C and D. These levels are up to 222-fold higher than those detected in the wells far from the military bases, indicating that military activities could be linked to the elevated PFAS levels. Risks associated with groundwater consumption were deemed unacceptable, with several PFAS detected at levels exceeding the drinking water standards by orders of magnitude. Our observation underscores that groundwater in public wells near U.S. military bases in South Korea is heavily contaminated with PFAS and related chemicals at levels that could pose significant health risks, highlighting the urgent need for mitigation.