Per- and polyfluoroalkyl substances (PFASs) in Chinese drinking water: risk assessment and geographical distribution

Background: In recent years, the widespread presence of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in the environment and the related exposures and adverse health effects has received increasing attention. However, PFASs are not routinely monitored in drinking water in many parts of the world, including China. PFAS data are mainly generated by research studies. This paper provides an overview of the available research studies on PFASs in Chinese drinking water to better understand the current status of PFAS contamination and the potential for exposure. Results: The available studies provided PFAS data from 526 drinking water samples across 66 cities in China with a total of approximately 452 million inhabitants. We mapped the risk distribution associated with PFAS-contaminated drinking water in China by comparing the measured levels with recent international guidelines. The PFAS concentrations reported in more than 20% of the studied cities, likely affecting 98.5 million people, were above the maximum contaminant level issued by Vermont in 2019. Furthermore, we also investigated the human exposure to PFASs in drinking water by estimating total daily intakes based on Exposure Factors Handbook of Chinese Population. This study revealed that East China and the Southwest regions posed a relatively higher risk to the Chinese population and some cities in the Yangtze River basin such as Zigong, Jiujiang, Lianyungang and a considerable share of other cities have exceeded the health-based guidelines issued by EU and US agencies. Conclusion: Drinking water in many cities and regions in China is contaminated with PFASs at levels of concern. PFAS elimination of PFASs from drinking water in contaminated cities and affected regions in China is urgently needed. PFAS releases from industries and other sources need better control and reduction. Further monitoring in remote Chinese regions is needed to overcome the knowledge gaps for a more comprehensive understanding of population exposure. The current risk assessment of PFASs in China should be re-evaluated considering the most recent toxicological studies, to clarify if the guidelines need to be lowered as recently done in Europe and the United States. This is necessary to have the best national base for risk assessment and a science-based driver for countermeasures.