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SMALL FISH MULTI-ENDPOINT BIOASSAY DEVELOPMENT
Citation:
Lothenbach, D B., K. M. Flynn, R. D. Johnson, P N. Fitzsimmons, D E. Hammermeister, F W. Whiteman, AND P. K. Schmieder. SMALL FISH MULTI-ENDPOINT BIOASSAY DEVELOPMENT. Presented at Joint Annual Meeting of SETAC/SOT Northland Chapter, USEPA, Duluth, MN, April 9-10, 2002.
Description:
The U.S. EPA is required to regulate waterborne chemical contaminants. To make decisions regarding what to regulate and what levels of contaminant are acceptable, the Office of Water needs several types of toxicological information: hazard identification data, and dose-response data. Current methods that rely on rodent models for generating the required information have several limitations that include: a) rodents do not drink much water so delivering an effective toxicant dose is difficult, b) determination of some effects such as cancer requires exposure times of up to two years, c) sample sizes that are adequate for determining low frequency events such as cancer or developmental anomalies are costly, and d) assessing the effects of "naturally" occurring chemical mixtures requires the preparation of water concentrates which is costly and difficult to do with fidelity. Several divisions of the National Health and Environmental Effects Research Lab (NHEERL) are working together to develop a small fish bioassay to generate data on several endpoints that will be useful for performing risk assessments on waterborne contaminants. To determine how long an exposure time is necessary to achieve carcinogenic sensitivity into the assay, the first few assays expose medaka (Oryzias latipes) a small aquarium fish to chemical contaminants for up to one year. Samples for histopathology and mutation are taken every three months. Other endpoints incorporated into the assay include growth, lethality, reproductive parameters such as fecundity and fertility and development. This poster presents data from the first chemical being used to develop the assay, dichloroacetic acid (DCA).
This abstract does not necessarily reflect EPA policy.