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U.S. EPA’s Four Lab Study: Integrated Assessment of Complex Disinfection Byproduct Mixtures - Abstract
Citation:
PRESSMAN, J. G., R. J. MILTNER, T. F. SPETH, S. D. RICHARDSON, M. G. NAROTSKY, E. S. HUNTER, J. E. SIMMONS, G. E. RICE, AND L. K. TEUSCHLER. U.S. EPA’s Four Lab Study: Integrated Assessment of Complex Disinfection Byproduct Mixtures - Abstract. Presented at American Water Works Association Annual Conference and Exposition, San Diego, CA, June 14 - 18, 2009.
Impact/Purpose:
To share information
Description:
Chemical disinfection of drinking water is considered one of the major public health triumphs of the 20th century, as it reduces concentrations of potentially pathogenic microorganisms resulting in corresponding decreases in morbidity and mortality from water-borne diseases. An unintended consequence of disinfection with oxidizing chemicals is the formation of complex mixtures of disinfection byproducts (DBPs). More than 600 individual DBPs have been identified, some of which are reproductive/developmental toxicants or carcinogens in experimental animal test systems. Despite intensive analytic chemistry efforts, typically more than 50% of the mass of total organic halide formed during water disinfection remains unknown. Because of the widespread human exposures to DBP mixtures in the U.S. and in developed/developing nations, the U.S. EPA undertook a comprehensive toxicological evaluation of DBP concentrates. Dubbed the “Four Lab Study” because planning and execution required the collaboration of four of the National Laboratories of the U.S. EPA’s Office of Research and Development, the study examined the mutagenic potential of the concentrates and the reproductive and developmental consequences of multi-generation oral exposure to drinking water DBP concentrates (136-fold higher than found in treated waters). This session opens with an overview, which places this project into context, providing the background necessary to understand this complex project. Presentations follow describing the preparation of the concentrates using a newly developed reverse osmosis procedure, and the chemical analysis of the concentrates that were produced. Two in vitro assays are described, assessing the results of mutagenicity of these concentrates, and the effects on trophoblast cells obtained from full term human placentas. In vivo assessment of prenatal, reproductive, neurobehavioral, and immunological developmental outcomes of the multigenerational rodent bioassay conducted using the drinking water concentrates will be described in detail. The final presentation will discuss the risk assessment implications of the four lab study for complex DBP mixtures.
