Per- and polyfluoroalkyl substances (PFASs) in urban PM2.5 samples from Curitiba, Brazil

Per-and polyfluoroalkyl substances (PFASs), also known as "forever chemicals" received significant attention during recent years due to their environmental persistence and emerging evidence on their toxicity to humans. In this work we present the first measurements of PFASs in inhalable fraction of airborne particles PM2.5 (particulate matter that has a diameter <2.5 & mu;m) in Brazil collected during Covid restriction period. Three PFASs that included perfluorooctanesulfonic acid (PFOS), a restricted by Stockholm convention perfluorooctanoic acid (PFOA), and 6:2 fluorotelomer sulfonate (6:2 FTS) were detected at concentrations up to 0.3 pg/m3. These values do not include uncertainties associated with potential adsorption of gas phase PFASs on the filters but may be lower than those generally occurring at Curitiba, Brazil due to an abrupt reduction in industrial activities and a major decrease in the use of transport during Covid lockdown. Although current air quality regulations do not set inhalable limits for PFASs, there is a concern that these substances can accumulate in human body. The detection of 6:2 FTS in PM2.5 samples is a cause for concern due to its persistence in the atmosphere and emerging evidence that FTS could have health effects comparable with those of PFOA and PFOS. Multiple pollution sources of PFAS in Curitiba were considered based on airmass trajectories and wind roses. Our results raise the question of whether the observed PFOS in Curitiba is linked to sulfluramid, a pesticide that is permitted for use in Brazil.