Probabilistic Health Risk and Loss of Disability-Adjusted Life Years for N-Nitrosodimethylamine in Asian Drinking Water: Assessment and Control Strategies.

Abstract

N-Nitrosodimethylamine (NDMA) is a teratogenic, mutagenic, and carcinogenic compound, which has been detected in many daily usable items, including drinking water, food, tobacco smoke, and cosmetics. It can be formed in drinking water during the disinfection process and has been detected in numerous drinking water systems worldwide, posing significant health issues. NDMA in drinking water is linked to disinfection processes such as chloramination, chlorination, and ozonation. In this study, multipathway exposure and risk of NDMA in drinking water were analyzed for Asia using the probabilistic concept. The major pathways of exposure include ingestion with drinking water, inhalation, and dermal contact during bathing, showering, swimming in chlorinated swimming pools, and house-cleaning. The overall chronic daily intake through different pathways was predicted to be 6.70 × 10^-7 mg/kg-day. The estimated average lifetime cancer risk was 3.42 × 10^-5, exceeding the US Environmental Protection Agency (USEPA)'s acceptable threshold of 1.0 × 10^-6 by 34.2 times, highlighting health concerns. The loss of disability-adjusted life years (DALYs) was estimated to be 2455 and 10,056 for bladder and liver cancers, translating to an economic burden of approximately US$128 and US$523 million, respectively. The loss of DALYs was 5.02 × 10^-7 and 2.06 × 10^-6 per person per year (pppy) for bladder and liver cancer respectively. Several possible strategies were highlighted to control NDMA in drinking water. The findings underscore the need for establishing stricter regulations, improved finished water quality, exposure reduction, and risk mitigation measures.