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APPROACHING THE TOXICITY OF DISINFECTION BY-PRODUCTS IN DRINKING WATER AS A MIXTURE PROBLEM
Citation:
Teuschler, L K. AND J E. Simmons. APPROACHING THE TOXICITY OF DISINFECTION BY-PRODUCTS IN DRINKING WATER AS A MIXTURE PROBLEM. JOURNAL OF THE AMERICAN WATER WORKS ASSOCIATION 95:131-138, (2002).
Description:
Abstract
Assessment of human health risk from exposure to disinfection by-products (DBPs) in drinking water is of concern because of the wide spread exposure of persons who use disinfected water. Taken as a body of literature, epidemiologic studies on chlorinated drinking water offer some evidence of an association with certain cancers and reproductive and developmental effects such that further investigations are warranted. In addition, there exists evidence of mutagenicity in in vitro studies of drinking water extracts and evidence of carcinogenicity, reproductive effects, nephrotoxicity and hepatotoxicity in in vivo single-chemical studies at high doses of DBPs. Because typical human exposures are to extremely low levels of DBPs, it is hypothesized that any health risk is likely to be attributable to factors other than exposure to any single DBP. Three approaches are suggested for the evaluation of DBP mixtures, based on expert panel recommendations in an International Life Sciences Institute report (ILSI, 1998). These include: 1) toxicologic studies of simple defined mixtures; 2) toxicologic studies using reproducible disinfection scenario samples; and 3) toxicologic or epidemiologic studies on direct drinking water samples. This paper suggests that all three approaches are valid and can provide data that are applicable to the risk assessment of DBPs. Furthermore, it is postulated that high-dose, single-chemical animal toxicity studies alone are insufficient to fully characterize DBP health risks. A concentrated effort by a multidisciplinary team of researchers is necessary to generate the appropriate data to address this problem.