Chemical mixtures in source water and drinking-water

Overview

Drinking-water and its sources invariably contain a number of chemicals, as a result of both natural occurrence and as a consequence of human activity. As the number of chemicals being detected in source water and drinking-water grows, it raises the question of whether substances should be considered individually or together, for risk assessment and management, as well as for regulatory purposes.

This document provides an overview of available tools and practical recommendations to support the assessment and management of risks to human health associated with chemical mixtures in drinking-water and its sources. The guidance builds upon the World Health Organization’s International Programme on Chemical Safety framework on combined exposures to multiple chemicals. The framework supports priority setting for assessing and managing chemical mixtures and its use is illustrated through a number of case studies relevant to the source water and drinking-water context.