Occurrence of per- and polyfluoroalkyl substances in water: a review

Per- and polyfluoroalkyl substances (PFASs) have drawn increasing concern due to their widespread presence and persistence in the environment. In contrast, methods and manuals have been developed only recently to provide recommended analysis procedures for a growing list of selected PFASs, with more quality assurance and quality control (QA/QC) measures incorporated to ensure data robustness. This review examined studies on the environmental occurrence of PFASs in different water systems in the United States (US) along with similar studies in the other countries. The review has thus revealed a few patterns regarding the environmental occurrence of PFASs having different molecular features, the impact of possible upstream PFAS sources, and the effects of water treatment facilities. Further research is needed to analyze a wider array of PFASs, particularly those playing roles in PFAS degradation pathways. The review also indicates a need for technologies capable of destructing PFASs in addition to those separation processes currently implemented at water treatment facilities to mitigate the environmental presence of PFASs.