Being prepared for the drinking water contaminants of tomorrow: An interdisciplinary approach for the proactive risk governance of emerging chemical and microbial drinking water contaminants

“Access to safe drinking water is a fundamental human need and, therefore, a basic human right. Contaminated water jeopardizes both the physical and social health of all people”: such is the importance of safe drinking water, as stated by Kofi Annan, former Secretary-General of the United Nations, on World Water Day 2001. While some countries are still struggling to protect their citizens from well-known drinking water contaminants, potential new drinking water risks from newly-identified chemical and microbial aquatic contaminants are appearing globally. The increasing detection of these emerging contaminants has been advanced by a combination of social, technological, regulatory, climatological and demographic developments. Recent examples of emerging contaminants are perfluoroalkyl and polyfluoroalkyl substances (PFAS), sapoviruses, pharmaceuticals and colistin resistant bacteria. Whether emerging aquatic contaminants are a concern for drinking water safety depends on their exposure and hazard potential, which is influenced by a range of various determinants, including their mobility, toxicity and persistence in the environment, the severity and duration of the health effects caused by the contaminant, and the possibility for, and efficacy of, protective measures. Evidence, however, of these determinants is often limited. The challenge of protecting public health from emerging drinking water contaminants, therefore, does not only relate to identifying emerging contaminants as soon as possible, but also to prioritising the impact on human health which these contaminants have when evidence on their exposure and hazard potential is limited. Once identified and assessed, the challenge of effective risk communication under uncertainty needs to be dealt with as well. In this dissertation, an integrated approach to facilitate the early warning of, and communication on, emerging chemical and microbial drinking water contaminants has been developed...