Levels and transport behavior of ionic per- and polyfluoroalkyl substances in the atmosphere of urban pollution scenario: An in-situ investigation of a wastewater treatment plant in Wuxi, China

Abstract

The levels of ionic per- and polyfluoroalkyl substances (iPFASs) in atmospheric particulate matter (PM_2.5), wastewater, and aqueous aerosol collected at a municipal WWTP in Wuxi were investigated. The concentration of Σ₂₀iPFASs in PM_2.5 collected from the WWTP (72.2 pg/m³, monthly average) was slightly higher than that from the control point (58.4 pg/m³). Furthermore, the HYSPLIT model implied that the iPFASs pathways of control point and WWTP were totally different under identical meteorological conditions and that WWTP could be a source of iPFASs in urban environment. A comparison of the levels and compositions of iPFASs in aeration tank wastewater (203 ± 118 ng/L), effluent (392 ± 145 ng/L), and aqueous aerosols (58.5 ± 11.7 ng/L) samples using the t-stochastic neighborhood embedding algorithm revealed similar pollution fingerprints in aqueous aerosols and aeration tank wastewater, which implied that aqueous aerosols could be originating from the aeration tanks of WWTP and that aqueous aerosols may serve as a carrier for the transport of iPFASs from wastewater to atmosphere. Forward trajectory analysis indicated that the priority contaminated areas were more than 200 km southeast of the WWTP source, suggesting that iPFASs emitted from the WWTP were likely to undergo long-range atmospheric transport after entering the atmosphere via aqueous aerosols.