Target, suspect, and non-target screening of per- and poly-fluoroalkyl substances in wastewater treatment plant effluents in South Korea using ion mobility spectrometry-mass spectrometry

This study used target, suspect, and non-target screening, to assess the presence of per- and polyfluoroalkyl substances (PFASs) in domestic (municipal) and industrial wastewater treatment plants (WWTPs) in South Korea. Target analysis quantified 20 PFASs in the WWTP effluents. Total concentration of PFASs ranged from 69.1 to 79.6 ng/L and the concentrations of perfluorobutanoic acid (PFBA) (mean: 15.6 ng/L, median: 14.9 ng/L) and perfluorooctanoic acid (PFOA) (mean: 14.7 ng/L, median: 12.7 ng/L) were higher than those of other PFASs. Compared to 2010, there was an overall increase in perfluoroalkyl carboxylic acids (PFCAs), particularly perfluoroheptanoic acid, (PFHpA), which showed a nearly 10-fold increase, with current concentrations reaching 9.5 ng/L. Suspect and non-target screening with ion mobility spectrometry (IMS)-mass spectrometry was used to identify additional PFASs based on their exact mass, collision cross-section (CCS), and tandem mass spectrometry fragmentation patterns. Twenty compounds were identified as PFAS compounds through suspect screening at a confidence level (CL) of 3 or higher, with five compounds identified at CL 2. Additionally, fragment-based, suspect and non-target screening identified emerging PFASs, including FBSA, a n:2 fluorotelomer-based non-polymer, and bistriflimide, all with CL 2. Semi-quantification of identified PFASs revealed that the concentrations of PFASs identified by suspect and non-target screening were higher than those of the target PFASs, especially in industrial wastewater effluents.