Multipathway health risk assessment on disinfection byproducts of drinking water in central China: a study of 15,280 samples

Disinfection is essential for protecting human health from microorganisms in drinking water. In addition to killing microorganisms, disinfection can introduce disinfection byproducts (DBPs), which impose detrimental effects on human health. In this study, a total of 15,280 water samples were monitored in 120 counties of Hunan Province, Central China, in periods ranging from 1 July 2023 to 31 December 2024. We evaluated the health risks of DBPs in drinking water through various exposure routes and conducted a comprehensive analysis of different factors that impact the health risks associated with these DBPs. The overall carcinogenic and noncarcinogenic risks resulting from exposure to DBPs through multiple pathways were 1.15 × 10^-5 and 2.59 × 10^-2, respectively. For different exposure routes, oral exposure to DBPs contributed the most to carcinogenic risk (1.13 × 10^-5) and noncarcinogenic risk (2.52 × 10^-2). The subgroup analysis revealed that the younger the child, the greater health risk they faced. The carcinogenic and noncarcinogenic risks for children aged 1-2 years were 2.56 × 10^-5 and 5.75 × 10^-2, respectively. Our study indicated that the potential carcinogenic risk of DBPs should be considered, and possible actions should be implemented to mitigate these health risks.