EPA Science Inventory

A MULTIPLE-PURPOSE DESIGN APPROACH TO THE EVALUATION OF RISKS FROM COMPLEX MIXTURES OF DISINFECTION BY-PRODUCTS

Citation:

Teuschler, L., C. GENNINGS, W. M. stiteler, R. Hertzberg, J. T. Colman, A. Thiyagarajah, J. C. lipscomb, W. R. Hartley, AND J. E. Simmons. A MULTIPLE-PURPOSE DESIGN APPROACH TO THE EVALUATION OF RISKS FROM COMPLEX MIXTURES OF DISINFECTION BY-PRODUCTS . DRUG AND CHEMICAL TOXICOLOGY. Marcel Dekker Incorporated, New York, NY, 23(1):307-321, (2000).

Description:

Drinking water disinfection has effectively eliminated much of the morbidity and mortality associated with waterborne infectious diseases in the United States. Various disinfection processes, however, produce certain types and amounts of disinfection by-products (DBPs), including trihalomethanes (THM), haloacetic acids, haloacetonitriles, and bromate, among others. Human health risks from the ubiquitous exposure to complex mixtures of DBPs are of concern because existing epidemiologic and toxicologic studies suggest the existence of systemic or carcinogenic effects. Researchers from several organizations have developed a multiple-purpose design approach to this problem that combines efficient laboratory experimental designs with statistical models to provide data on critical research issues (e.g., estimation of human health risk from low-level DBP exposures, evaluation of additivity assumptions as useful for risk characterization, estimation of health risks from different drinking water treatment options). A series of THM experiments have been designed to study embryonic development, mortality and cancer in Japanese medaka (Oryzias latipes) and liver and kidney endpoints in female CD-1 mice. The studies are to provide dose-response data for specific mixtures of the 4 THMs, for the single chemicals, and for binary combinations. The dose-levels and mixing ratios for these experiments were selected to be useful for development and refinement of three different statistical methods: testing for departures from dose-additivity; development of an interactions-based hazard index; and use of proportional-response addition as a risk characterization method. Preliminary results suggest that dose-additivity is a reasonable risk assessment assumption for DBPs. The future of mixtures research will depend on such collaborative efforts that maximize the use of resources and focus on issues of high relevance to the risk assessment of human health.

Purpose/Objective:

journal article

Record Details:

Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Start Date: 02/23/2000
Completion Date: 02/23/2000
Record Last Revised: 04/22/2014
Record Created: 05/27/2003
Record Released: 05/27/2003
OMB Category: Other
Record ID: 56914

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL CENTER FOR ENVIRONMENTAL ASSESSMENT

CINCINNATI OH