Management of Disinfection Byproducts in Drinking Water: A Roadmap for Change

Many countries have developed regulations to limit disinfection byproduct (DBP) concentrations, principally trihalomethanes, in drinking water with the expectation that these DBPs would serve as surrogates for the risks from unregulated and unknown DBPs. However, epidemiological studies in combination with toxicological data now provide substantive evidence that chlorinated drinking water leads to an increased risk of bladder cancer, which is not adequately reflected in many existing DBP standards and guidelines, particularly for individuals having common genetic polymorphisms. New approaches to the management of DBPs are needed to reduce DBP exposure, particularly for water supplies with elevated iodide and bromide concentrations where local community led action may be needed in the absence of regulatory changes. Here, a Roadmap for change in the management of DBPs, from compliance as a minimum, through three stages of sensible, precautionary approaches, and finally a Precautionary Principle approach, to suit local conditions and the community’s appetite for the risks from DBPs and their willingness to pay for measures to reduce DBPs beyond compliance to as low as reasonably practicable, is presented. Implementation of the Roadmap should be conducted in consultation with the community and the relevant health regulator to ensure that confidence in the safety of drinking water remains high.