Screening and risk assessment of priority organic micropollutants for control in reclaimed water in China

Organic micropollutants (OMPs) in reclaimed water have been frequently detected over the past decades, posing significant risks to ecosystems and human health. Given the complexity of these pollutants and the differences in their risk and toxicity, current assessments remain incomplete. This study conducted a large-scale investigation of OMPs in reclaimed water across China and developed a comprehensive multi-criteria integrated scoring method based on OMP toxicity and exposure potential. This method aims to protect aquatic organisms and human health by screening and prioritizing OMPs in reclaimed water, classifying their priority levels, and creating a prioritized control list. The study quantified OMP exposure potential, environmental persistence, bioaccumulation, and impacts on ecology and human health. The survey detected 369 OMPs from 11 chemical classes, with 325 compounds passing pre-selection. According to the prioritization scheme, 29 OMPs were identified as high priority, 171 as medium priority, and 125 as low priority. The BPs and Other Industrial Chemicals categories had the highest average maximum concentrations, followed by HPCCs and PAEs. High-priority pollutants were dominated by PAHs and PCBs, each comprising 31.03 %. Medium- and low-priority groups were mainly composed of Pesticides. PAHs and PCBs showed higher risk quotients, indicating significant ecological risks, while PCB 126, BaP, and PFOA exhibited high toxicity and potential health risks. This study provides valuable information for controlling priority pollutants in Chinese reclaimed water and establishes a foundation for OMP risk management. Future research should intensify monitoring to ensure the safe and sustainable use of water resources.