Suspect and non-target screening for emerging contaminants of potential concern and risk assessment in wastewater treatment plants: A case study of a typical industrial city in China

Wastewater treatment plants (WWTPs) are a major source of emerging contaminants (ECs) in the aquatic environment. For this reason, a methodology is required that can comprehensively identify and prioritize pollutants in toxicological terms. In this study, by using a combined target, suspect, and non-target screening strategy, we investigated the occurrence and removal of emerging contaminants in three WWTPs in China. The 437 substances screened were categorized into five kinds including 145 pharmaceutical and personal care products (PPCPs), 17 organophosphate esters, 34 pesticides, 24 poly- and perfluoroalkyl substances, and 217 chemical raw materials intermediates. The removal rates of ECs were categorized into four classes by investigating the ECs in influent and effluent water, and twelve pollutants of priority concern were screened by combining the removal rates, detection rates and double-bond equivalent values of pollutants in different wastewater treatment plants. Under the framework of Toxicological Priority Index (ToxPi), an extended ranking of all identified pollutants by combining instrumental response and detection frequency was carried out and a priority control list of fifteen pollutants was obtained, of which perfluorooctane sulfonate (PFOS) had the highest risk priority. This study presents a methodology for a comprehensive pollutant identification and prioritization exercise to facilitate wastewater management and for ecological risk assessment.