Although per- and polyfluoroalkyl substances (PFASs) have always been a key issue in the global environmental field, there are still a lot of undiscovered PFASs in the environment due to new PFAS alternatives developed by manufacturers. Wastewater treatment plants (WWTPs), as one of the sources for PFASs, are an important part of the process of releasing new PFASs into the environment. In this study, suspect screening and PFAS homologue analysis with quadrupole time-of-flight tandem mass spectrometry were used to discover PFASs in wastewater from a WWTP near Yangtze River. Fifteen classes with 90 PFASs were identified, including 12 legacy PFASs (2 classes), 41 previously reported PFASs (7 classes), and 37 new PFASs (6 classes), and 18 of these PFASs were also detected in the nearby Yangtze River. Only 1 PFAS class was removed through the treatment processes (fold change < 1/6). Conversely, 4 PFAS classes increased through the treatment processes (fold change > 6), which could be the transformation products of PFAS precursors. These results implied that most discovered PFASs were not effectively removed in the WWTP. Chlorine-substituted perfluoroalkyl carboxylates (Cl-PFCAs) as the main component of wastewater were detected only in downstream, meaning that Cl-PFCAs in downstream possibly originated from the WWTP.

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