Chlorinated water and its hidden risks: a study of chlorine disinfection by-products

Chlorination is widely used for disinfecting drinking water and swimming pools due to its cost-effectiveness and reliability. However, chlorination can lead to the formation of chlorine disinfection by-products (CDBPs), which may pose potential health risks following long-term exposure. Although guideline values for several CDBPs have been established by the World Health Organisation (WHO), uncertainties remain regarding the health impacts of many regulated and unregulated by-products. This study evaluates the health risks associated with different chlorine disinfectants and assigns comparative carcinogenic and non-carcinogenic risk scores using advanced assessment approaches. Results indicate that swimming pools represent a significant source of CDBP exposure, with competitive swimmers experiencing higher health risks than recreational swimmers due to prolonged exposure duration. Liquid chlorine and calcium hypochlorite exhibit approximately 3.3 times higher carcinogenic risk and four times higher non-carcinogenic risk compared with sodium hypochlorite. Infants and toddlers are identified as particularly vulnerable, showing a 1.7-fold higher carcinogenic risk and a twofold higher non-carcinogenic risk compared with adults. These findings highlight the need for improved exposure assessment, targeted risk management strategies, and informed decision-making to reduce CDBP-related health risks, particularly in drinking and recreational water environments for vulnerable populations.