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RESULTS OF THE NATIONWIDE DBP OCCURRENCE STUDY: IDENTIFICATION OF NEW AND INTERESTING DBPS
Citation:
Richardson, S D., A D. Thruston Jr., S. W. Krasner, AND H. S. Weinberg. RESULTS OF THE NATIONWIDE DBP OCCURRENCE STUDY: IDENTIFICATION OF NEW AND INTERESTING DBPS. Presented at International Society of Exposure Analysis - International Society of Environmental Epidemiology Conference, Vancouver, Canada, August 11-15, 2002.
Impact/Purpose:
(1) Use toxicity-based approach to identify DBPs that show the greatest toxic response. (2) Comprehensively identify DBPs formed by different disinfectant regimes for the 'Four Lab Study'. (3) Determine the mechanisms of formation for potentially hazardous bromonitromethane DBPs.
Description:
Drinking water disinfection by-products (DBPs) are formed when disinfectants, such as chlorine, react with natural organic matter and bromide present in the water. Chloroform was the first DBP identified in drinking water (in 1974), and was subsequently shown (along with other trihalomethanes, bromodichloromethane, dibromochloromethane, and bromoform) to cause cancer in laboratory animals. In the 25 years following the discovery of chloroform, several hundred DBPs have been identified and reported in the literature. However, only a very few DBPs have been studied for adverse health effects. Because health effects studies are extremely expensive ($1-2 million), it is not possible to simply test all DBPs that are reported. Also, it is not wise to test DBPs for which there is no quantitative occurrence information (to know how widespread a particular DBP was and at what concentrations it is present). Therefore, we have initiated a nationwide occurrence study to quantify 'high priority' DBPs and to identify any new ones that have not been previously reported. The DBPs to be quantified were the result of a major effort by experts who scrutinized all DBPs reported in the literature for probable adverse health effects (based on their chemical structures). The 'top 50' DBPs resulting from this prioritization were included for this nationwide occurrence study. Drinking water samples are being collected across the U.S. from waters that use chlorine, ozone, chlorine dioxide, or chloramine for disinfection. Results from the quantitation of the approximately 50 high priority DBPs will be presented in an accompanying paper by Krasner et al. This paper will detail the identification of new, previously unidentified DBPs in the drinking water samples. These DBPs include many new brominated DBPs including bromo-acids (such as dibromopropenoic acid, tribromopropenoic acid, and dibromobutanoic acid), bromo-ketones, and bromo-acetaldehydes, such as dibromoacetaldehyde.