Emission of airborne contaminants of emerging concern from wastewater treatment processes

Wastewater treatment plant (WWTP) influents and effluents are known to contain contaminants of emerging concerns (CECs), including surfactants, industrial chemicals, and pharmaceuticals (Freeling et al., 2019; Lenka et al., 2021). WWTP involve numerous steps, e.g., aeration, that may facilitate the transfer of these compounds to the atmosphere through aerosolisation or volatilisation. Understanding the fate of these pollutants during wastewater treatment is important, as it could inform emission pathways, atmospheric exposure, and potential environmental and human health impacts.In this study, particulate matter (PM, total suspended particles) samples collected from the grit chamber, secondary settler, and a staff building at a WWTP in Brazil were analysed using high-resolution mass spectrometry (HRMS)-based targeted and non-targeted approaches. Targeted analysis demonstrated both legacy and new generation per and polyfluoroalkyl substances (PFAS) in PM samples, with perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) dominating the PFAS profiles, indicating continued inputs of these compounds into wastewater cycles years after regulatory restrictions.Non-targeted analysis (NTA) revealed the presence of a broad range of CECs, including nitroaromatics, insecticides, personal care products, and industrial intermediates. Semi-targeted analysis of the PM samples identified the highest abundance of 4-nitrophenol (a nitroaromatic compound with known adverse effects on climate and health) in the grit-chamber samples.Overall, our results emphasise that WWT processes may represent a potential source of PFAS and other CECs to the atmosphere. Reference:Lenka, S. P., Kah, M., & Padhye, L. P. (2021). A review of the occurrence, transformation, and removal of poly- and perfluoroalkyl substances (PFAS) in wastewater treatment plants. Water Research, 199, 117187. https://doi.org/10.1016/j.watres.2021.117187Freeling, F., Alygizakis, N. A., von der Ohe, P. C., Slobodnik, J., Oswald, P., Aalizadeh, R., Cirka, L., Thomaidis, N. S., & Scheurer, M. (2019). Occurrence and potential environmental risk of surfactants and their transformation products discharged by wastewater treatment plants. Science of The Total Environment, 681, 475-487. https://doi.org/10.1016/j.scitotenv.2019.04.445