N-nitrosodimethylamine (NDMA) in Drinking Water: A Probabilistic Health Risk Assessment in Asia

N-nitrosodimethylamine (NDMA) has been detected in many daily usable items including drinking water, foods, and cosmetics. It can be formed in drinking water during the disinfection process, which has been detected in numerous drinking water systems worldwide, posing significant public health issues. NDMA in drinking water is often linked to disinfection processes such as chloramination, chlorination and ozonation. In this study, multi-pathway human exposure and risk of NDMA in drinking water was analyzed for Asia continent using the probabilistic concept. The major pathways of NDMA exposure include ingestion with drinking water, and inhalation and dermal contact during bathing, showering, swimming in chlorinated swimming pools and house-cleaning. The estimated average lifetime cancer risk for NDMA was 3.42×10⁻⁵, exceeding the USEPA's acceptable threshold of 1.0×10⁻⁶ by 34.2 times, highlighting public health concerns. Several possible strategies were highlighted to control NDMA in drinking water. The findings underscore the need for establishing stricter regulations, improved finished water, NDMA exposure reduction and risk mitigation measures for drinking water.