In-vitro inhaled bioavailability of particle-bound per- and polyfluoroalkyl substances: Affecting factors and risk assessment

Concerns regarding the inhaled risks of per- and polyfluoroalkyl substances (PFAS) in atmospheric particulate matter (APM) are continuously increasing. In this study, we collected APM of three sizes (PM1.0, PM2.5, and PM10) to investigate the bioavailability of PFAS. An in-vitro simulation method was employed using two simulated lung fluids: modified Gamble's solution (MGS) and artificial lysosomal fluid (ALF). Among the APM samples, PFAS concentrations in PM1.0 and PM2.5 were significantly higher than those in PM10. In addition to long-chain PFAS, short-chain and emerging PFAS also exhibited high concentrations. Regarding the inhaled bioavailability of PFAS in APM, we found that PFAS generally had high inhalation bioavailability fractions (IBAFs) in both MGS and ALF. IBAFs for most PFAS reached equilibrium after 1-day incubation period, with the size of APM and hydrophobicity of PFAS influencing IBAFs in both MGS and ALF. The bioavailability of PFAS in ALF was generally higher that in MGS. If the bioavailability of PFAS in APM with simulated lung fluids is not considered, the health risk of PFAS may be overestimated by 21% to 47% in the interstitial fluid of lung cells and by 17% to 33% in lung cells.