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CHEMICAL AND TOXICOLOGICAL EVALUATION OF CHLORINATED AND OZONATED-CHLORINATED DRINKING WATER: A COLLABORATION OF THE FOUR NATIONAL LABS OF THE U. S. EPA
Citation:
Richardson, S D., L K. Teuschler, A D. Thruston Jr., T F. Speth, R J. Miltner, G Rice, K M. Schenck, S. W. Krasner, H. Weinberg, AND J E. Simmons. CHEMICAL AND TOXICOLOGICAL EVALUATION OF CHLORINATED AND OZONATED-CHLORINATED DRINKING WATER: A COLLABORATION OF THE FOUR NATIONAL LABS OF THE U. S. EPA. Presented at American Society for Mass Spectrometry, Chicago, IL, May 27-31, 2001.
Description:
CHEMICAL AND TOXICOLOGICAL EVALUATION OF CHLORINATED AND OZONATED-CHLORINATED DRINKING WATER: A COLLABORATION OF THE FOUR NATIONAL LABS OF THE U.S. EPA
Susan D. Richardson1, Linda K. Teuschler2, Alfred D. Thruston, Jr.,1 Thomas Speth3, Richard J. Miltner3, Glenn Rice2, Kathleen M. Schenck3, Stuart W. Krasner4, Howard S. Weinberg5 and Jane Ellen Simmons6 .
1National Exposure Research Laboratory, U.S. EPA, Athens, GA; 2National Center for Environmental Assessment, U.S. EPA, Cincinnati, OH; 3National Risk Management Research Laboratory, U.S. EPA, Cincinnati, OH; 4Metropolitan Water District of Southern California, La Verne, CA; 5Department of Environmental Sciences & Engineering, University of North Carolina, Chapel Hill, NC; 6National Health and Environmental Effects Research Laboratory, U.S. EPA, RTP, NC;
Disinfection by-products (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 only about 50% of the mass of total organic halide. Toxicological evaluation of these complex DBP mixtures is a critical data gap; therefore, the Office of Research and Development (ORD) of the U.S. Environmental Protection Agency (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 GC/MS techniques (high and low resolution electron ionization and chemical ionization mass spectrometry). An attempt was made to comprehensively identify all DBPs present. BF3/methanol and pentafluorobenzylhydroxylamine (PFBHA) derivatizations were carried out to identify carboxylic acids and carbonyl containing compounds, respectively. Many DBPs were identified, including brominated and iodinated compounds, such as bromo- and iodo-trihalomethanes and -acetaldehydes, halonitromethanes, halopropanones, halonitriles, and haloacetamides. In addition, approximately 50 high priority DBPs were quantified in these samples. These high priority DBPs were selected by toxicologists from hundreds reported in the literature according to probable adverse health effects. Many of these, including MX [3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone] and brominated forms of MX (the so-called BMX's) were present in the drinking water concentrates.