Nontarget Screening and Occurrence of Emerging Per- and Polyfluoroalkyl Substances in Municipal and Semiconductor Industrial Wastewater: A Large-Scale Survey in China

Due to the lack of transparency in the production and applications of emerging per- and polyfluoroalkyl substances (PFAS), it is a huge challenge to grasp the real PFAS pollution profile in a specific region or industry by target analysis. This study collected extensive samples across China, including municipal wastewater from 9 major cities and wastewater from various manufacturing stages at 3 large semiconductor factories. Suspect and nontarget screening were conducted along with target analysis, and 82 PFAS in 25 classes were identified. Notably, this is the first study to investigate PFAS contamination in semiconductor wastewater on the Chinese mainland. Moreover, 13 classes of PFAS were reported for the first time worldwide in semiconductor wastewater, including multiple hydrosubstituted perfluoroalkyl carboxylic acid (mH-PFCA), ether-inserted PFCA (OPFCA), and perfluoroalkyl alcohol (PA) derivatives. The highest total concentrations of target, suspect, and nontarget PFAS in semiconductor wastewater (12 μg/L) were substantially higher than those measured in all municipal wastewater (25-950 ng/L). The composition of PFAS varied regionally in semiconductor wastewater. Total oxidizable precursor assay revealed the presence of unknown precursors (0.043-0.83 nmol/L), which cannot be directly monitored but may pose a greater PFAS contamination risk in semiconductor water treatment and discharge processes.