Risk Assessment of Inhalation Exposure to Per-and Polyfluoroalkyl Substances (PFASs) in Industrial, Urban-residential and Rural Areas Near Hyeongsan River, Pohang

The goal of this study was to evaluate human exposure to per- and polyfluoroalkyl substances (PFASs) in the air near the Hyeongsan River in Pohang, and to quantify associated health risks. The daily intake of PFOS was the highest, and those of PFBS, PFHxA, PFUnDA, and PFOA were also high. Humans were exposed more to ionic PFASs than to neutral PFASs. The exposure level of PFASs increased from upstream to downstream; this trend suggests that emission sources exist downstream. For the gaseous phase, the exposure level was highest to PFBS, which have the shortest carbon-chain length, whereas for the particulate phase, exposure was highest to PFOS. The exposure and distribution of PFAS congeners differed among sites and phases, which means that humans are exposed differently depending on the PFASs emitted from the emission source at each site, and on the physicochemical properties of PFASs. Inhalation exposure to PFASs was below the PFAS intake safety threshold, and the toxicity was also lower than the level allowed by WHO. However, health risks from long-term exposure to PFASs are of concern, and combining exposure by various routes may have a significant health effect. Therefore, continuous monitoring and risk assessment are required.