World Health Organization (WHO) Working Group Regarding Pharmaceuticals in Drinking Water

A World Health Organization (WHO) Working Group on Pharmaceuticals in Drinking Water has received world-wide attention in the last few years. The presence of pharmaceuticals in source and finished drinking water has generated concern among governments/regulators, member states, industry, municipalities, and the public. An increase in the use of pharmaceuticals is anticipated as the world population gets older. Also, there is an expected increase in the use of veterinary and agricultural drugs worldwide. There are a number of critical issues regarding the occurrence, human health effects, and treatment and disposal options for pharmaceuticals in the environment, drinking water, and wastewater treatment systems.

The Working Group consisted of scientists from Singapore, Japan, United Kingdom, Canada, Tanzania, Australia, Germany, Malaysia, Netherlands, and the United States. They have addressed:

1. environmental occurrence and sources of pharmaceuticals in finished drinking water and source water;
2. approaches to assess health risks to vulnerable populations;
3. environmental chemistry of pharmaceuticals in natural waters;
4. advances in treatment methods and analytical methods, including treatment effectiveness;
5. availability of data and information to assess risks to human health; and
6. existing pharmaceutical take-back and safe disposal programs to reduce water pollution.

As a member of the WHO Working Group, Dr. Edward Ohanian,  EPA Office of Water, was instrumental in the development and launching of the 4th Edition of the WHO Guidelines for Drinking-water Quality and the WHO Working Group's Report on Pharmaceuticals in Drinking Water, which were released on July 4, 2011 in Singapore during the Singapore International Water Week Convention. This report includes the assessment of risks to human health associated with long-term exposure to low concentrations of pharmaceuticals and the possible combined effects of mixtures of pharmaceuticals. The report concludes that the analysis of available data indicates that there is a significant margin of safety between the very low concentrations of pharmaceuticals that would be consumed in drinking water and the minimum therapeutic doses, which suggests a very low risk to human health. Based on this finding, the development of formal health-based guideline values for pharmaceuticals in WHO's Guidelines for Drinking water Quality is currently not considered to be necessary. The report also acknowledges that, although the current risk assessments indicate that the very low concentrations of pharmaceuticals found in drinking water are associated with a negligible human health risk, knowledge gaps exist. It would be of value to ensure that these margins are adequate for possibly sensitive subpopulations and to better characterize health risks, if any, from long-term, low-level exposures. In addition, future research should focus on developing methods or protocols for prioritizing pharmaceuticals in the context of an overall risk assessment for all drinking water hazards.