Aerosolisation of per- and polyfluoroalkyl substances (PFAS) during aeration of contaminated aqueous solutions

Environmental pollution by perand polyfluoroalkyl substances (PFAS), commonly known as "forever chemicals", is a major concern. Numerous studies have identified PFAS in various environmental matrices including groundwater, surface water, sea, soil, and atmosphere. Nevertheless, the atmospheric presence of PFAS remains an underexplored area. The exact sources of PFAS in the atmosphere and the mechanisms governing their transfer remain largely elusive. In this study, we investigated, for the first time, the influence of aeration on the aqueous-to-air transfer, of a range of short-, medium-, and long-chain PFAS from aqueous solutions contaminated with PFAS at concentrations and pHs relevant to those at industrial wastewater treatment. PFAS enriched aerosols were generated from the aqueous solutions under three tested pH conditions which were found to affect the partitioning of the individual PFAS. The extent of PFAS aerosolisation also showed a clear dependence on the analyte's carbon chain length and functional groups. Specifically, the propensity for partitioning into aerosols increased with increasing PFAS carbon chain length. Notably, perfluorosulfonic acids (PFSA) demonstrated a greater potential for aerosolisation compared to perfluorocarboxylic acids (PFCA). Legacy PFAS including perfluorooctanoic acid (PFOA) and perfluorosulfonic acid (PFOS) and a new generation replacement PFAS 8:2 Fluorotelomer sulfonate (8:2 FTS) showed a significant transfer to aerosols from the aqueous solutions. Our results suggest that processes involving aeration of contaminated water (including those at industry) with PFAS could potentially act as a source of atmospheric PFAS.