Advances in the Distribution, Transport, and Transformation of PFAS in the Drinking Water System: From Source to Tap

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) pose a significant threat to drinking water safety worldwide due to their extreme persistence, mobility, and documented adverse health effects. Currently, there is a lack of comprehensive reviews that systematically examine the behavior and transformation of PFAS across the drinking water system-from source to tap-incorporating recent advancements in precursor transformation, pipeline dynamics, and data-driven management. Our analysis synthesizes global data, revealing that PFASs are consistently detected in both source and finished water at nanogram-per-liter concentrations. Whereas conventional treatment technologies show minimal removal efficacy, advanced treatment processes such as granular activated carbon, anion exchange resins, and membrane filtration are constrained by high costs and material limitations. The review further highlights four key advancements: (1) the widespread occurrence of unidentified organic fluorides; (2) transformation pathways of PFAA precursors during oxidative treatment leading to recalcitrant byproducts; (3) dynamic PFAS retention-release mechanisms within distribution pipelines; and (4) machine learning-enabled tools for predicting contamination and optimizing treatment. These insights collectively enhance the understanding of PFAS persistence and transformation across the drinking water system, providing a scientific basis for improved regulation and control strategies. Finally, we propose current research challenges and suggest priority directions for future studies aimed at ensuring long-term drinking water security.