Evaluation of point-of-use drinking water treatment performance for typical per- and polyfluoroalkyl substances in tap water†

Per- and polyfluoroalkyl substances (PFASs) have been frequently found in surface water, groundwater and tap water, and drinking water intake was an important route of exposure. Because of the implementation of the Chinese Standards for Drinking Water Quality (GB 5749-2022) and the possible health risks, the PFAS level in tap water and the efficacy of preventive measures and point-of-use treatments needed further verification. In this study, we assessed PFAS contamination in municipal tap water (September 2023–August 2024 in Shanghai) and evaluated mitigation strategies. The concentration of ∑PFAS ranged from 45.2 to 155.6 ng L⁻¹, and was dominated by PFOA, PFBS, PFHxA, and PFBA. While all samples complied with China's current PFOA/PFOS regulations of drinking water, emerging health concerns warrant attention. The point-of-use treatment results showed that boiling and ultrafiltration (UF) are not effective in removing PFASs from tap water, while activated carbon/ion exchange resin filter jugs removed about 54.6% of ∑PFAS, but were still unsatisfactory. Compared to low removal in UF, reverse osmosis (RO) demonstrated near-complete elimination (>99%) through membrane rejection (52–79% contribution). All the analyzed bottled water was safe to drink. The exposure risk assessment found that infants and children had a higher daily intake of PFASs from drinking water, while RO and bottled water were effective in reducing the exposure risk. These findings highlight the need for enhanced drinking water treatment optimization and regulatory updates to address evolving PFAS contamination challenges.