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OCCURRENCE, GENOTOXICITY, AND CARCINOGENICITY OF EMERGING DISINFECTION BY-PRODUCTS IN DRINKING WATER: A REVIEW AND ROADMAP FOR RESEARCH
Citation:
RICHARDSON, S. D., M. J. PLEWA, E. D. WAGNER, R. S. SCHOENY, AND D. M. DEMARINI. OCCURRENCE, GENOTOXICITY, AND CARCINOGENICITY OF EMERGING DISINFECTION BY-PRODUCTS IN DRINKING WATER: A REVIEW AND ROADMAP FOR RESEARCH . MUTATION RESEARCH. Elsevier Science Ltd, New York, NY, 636(1-3):178-242, (2007).
Impact/Purpose:
(1) Use a toxicity-based approach to prioritize and 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:
Disinfection by-products (DBPs) are formed when disinfectants (chlorine, ozone, chlorine dioxide, or chloramines) react with naturally occurring organic matter, anthropogenic contaminants, bromide, and iodide during the production of drinking water. Here we review 30 years of research on the occurrence, genotoxicity, and carcinogenicity of 85 DBPs, 11 of which are currently regulated by the U.S., and 74 of which are considered emerging DBPs due to their moderate occurrence levels and/or toxicological properties. Our analysis identified 3 categories of DBPs of particular interest. Category 1 contains 8 DBPs with some or all of the toxicologic characteristics of human carcinogens: 4 regulated (bromodichloromethane, dichloroacetic acid, dibromoacetic acid, and bromate) and 4 unregulated DBPs (formaldehyde, acetaldehyde, MX, and NDMA). Categories 2 and 3 contain 43 emerging DBPs that are present at moderate levels (sub-low µg/L): category 2 contains the 26 of these that are genotoxic (including chloral hydrate, which is also a rodent carcinogen); and category 3 contains the remaining17 for which little or no toxicological data are available.