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INTEGRATED TECHNOLOGY-BASED TOXICOLOGY STUDIES ON DRINKING WATER DISINFECTION BYPRODUCTS (DBPS)
Citation:
Simmons, J E., S D. Richardson, T F. Speth, R J. Miltner, K M. Schenck, G Rice, L K. Teuschler, S. W. Krasner, AND H. Weinberg. INTEGRATED TECHNOLOGY-BASED TOXICOLOGY STUDIES ON DRINKING WATER DISINFECTION BYPRODUCTS (DBPS). Presented at Workshop on Application of Technology to Chemical Mixture Research, Fort Collins, CO, January 8-11, 2001.
Impact/Purpose:
Determine the actual concentrations of suspected health-impacting DBPs produced using non-chlorine disinfectants, how often they occur, under what conditions they are formed, and their fate and transport in the distribution system.
Description:
DBPs are formed by reactions of chemical disinfectants with natural organic matter in the source water. Although more than 300 DBPs are known, many remain unidentified; for chlorination, known DBPs account for ~50% of the mass of total organic halide. Toxicological evaluation of these complex DBP mixtures is a critical data gap; therefore, ORD/U.S. EPA has developed a research plan for joint chemical and toxicological characterization of real-world complex mixtures obtained by concentration of drinking water disinfected either by chlorination (post-chlorination) or by ozonation (pre-ozonation/post-chlorination) processes. In vivo and in vitro toxicological assessments are planned with a targeted focus on reproductive and developmental endpoints, including other target organs to the extent possible. Experiments have been conducted to 1) develop methods for reverse osmosis (RO) concentration of water spiked with bromide and iodide, 2) perform extensive chemical analysis of DBPs expected to be present at very low concentrations (in the ppt range) and 3) study the chemical stability of the concentrated water. RO samples were extracted with XAD resins and analyzed by advanced GC/MS techniques (high and low resolution electron ionization and chemical ionization mass spectrometry). An attempt was made to comprehensively identify all DBPs present. Many DBPs were identified, including brominated and iodinated compounds, such as bromo- and iodo-trihalomethanes and -acetaldehydes, halonitromethanes, halopropanones, halonitriles, and haloacetamides. Although pre-ozonation/post-chlorination did form a number of halogen-containing byproducts, they were fewer in number and lower in concentration than formed by post-chlorination. (This abstract may not reflect EPA policy.)