Quantifying public health risks in the WHO Guidelines for Drinking-water quality

Overview

The 3rd edition of the WHO Guidelines for Drinking-Water Quality proposes a preventive management framework for safe drinking water that is similar for all types of contaminants - microbial, chemical and radiological. Descriptions of the level of risk in relation to water are usually expressed in terms of specific health outcomes (such as cancer, diarrhoeal disease, HW FHWHUD).

A common unit for risk is essential here, since different contaminants cause health effects of widely varying severity and kinds, ranging, for example, from mild diarrhoea through crippling fluorosis to child death. This is the only way to enable comparison between the public health impact of various agents and intervention options.

The purpose of this particular report is to provide a discussion paper on the concepts and methodology of Disability Adjusted Life Years (DALYs) as a common public health metric and its usefulness for drinking-water quality. The approach is illustrated for several drinking-water contaminants already examined using the burden of disease approach; preliminary data are given for several other key contaminants.