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Chemistry, Toxicity and Health Risk Assessment of Drinking Water Disinfection ByProducts
Citation:
SIMMONS, J. E. AND L. K. TEUSCHLER. Chemistry, Toxicity and Health Risk Assessment of Drinking Water Disinfection ByProducts. Chapter 1, Mumtaz, M. (ed.), Principles and Practices of Mixtures Toxicology. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany, , 401-420, (2010).
Impact/Purpose:
Scientifically sound data and methods are needed to understand the chemical composition and potential toxicity of the whole DPB mixture.
Description:
Disinfection byproducts (DBPs) are formed by the reaction of oxidizing chemicals (such as chlorine, ozone and chloramines) used to control waterborne pathogens with natural organic material and other substances in water. DBP mixture composition varies as a function of geographic location, season, source water characteristics and disinfection scenario. While more than 500 DBPs have been identified, a substantial quantity of the total organic halide formed during water disinfection remains unknown. Toxicity (e.g. carcinogenicity, reproductive/developmental effects, hepatotoxicity, nephrotoxicity) from exposure to various individual DBPs and defined DBP mixtures has been demonstrated in experimental animals. Epidemiological investigations provide evidence of associations of varying strength between consumption of disinfected water and human health effects (e.g. bladder cancer, adverse reproductive/developmental outcomes). Scientifically sound data and methods are needed to understand the chemical composition and potential toxicity of the whole DBP mixture. The characterization of human health effects from DBP exposures and the subsequent establishment of regulatory levels must balance any risks associated with exposure to DBP mixtures against the proven public health benefits of reduced morbidity and mortality from water-borne diseases that result from water disinfection. The purpose of this chapter is to develop an understanding of DBPs in the context of a chemical mixtures issue, discuss current approaches to characterize DBP exposures, health effects and risks, and identify data gaps and future research needs to improve DBP mixture assessments.