United States Environmental Protection Agency Office of Research and Development National Exposure Research Laboratory Research Abstract Government Performance Results Act (GPRA) Goal 4 Annual Performance Measure #273 Significant Research Findings: Report on vitellogenin gene expression in minnows and pearl dace from control (non-dosed) and lakes dosed with EDCs in the Canadian Experimental Lake Area Scientific There is increasing concern about the potential impact of endocrine disrupting Problem and compounds (EDCs) on aquatic organisms. EDCs are compounds that interfere Policy Issues with the normal functioning of hormones in the body. Among the EDCs that are found in aquatic habitats are synthetic estrogens, which are used in contraceptives and other pharmaceuticals. The purpose of the study was to further develop a vitellogenin gene expression assay as an indicator of estrogen exposure. In order to investigate the effects of long term exposure to an endocrine disrupting compound on a whole lake ecosystem, Canadian Division of Fisheries and Oceans dosed a lake in the Experimental Lakes Area (ELA) of northwestern Ontario with 17a-ethynylestradiol (EE2) for three years beginning in 2001. EE2 was added to the lake at environmentally relevant levels with a target concentration of -4-6 ng/L. The U.S. EPA collaborated in this study by evaluating vitellogenin gene expression in indigenous fathead minnows (Pimephale promelcts) and pearl dace (Mctrgctriscus margctrita) collected from a reference lake and a continuously dosed lake and in laboratory cultured fathead minnows exposed to water and sediments from the dosed lake and reference lakes. Gene expression in indigenous male fathead minnows and pearl dace collected at all time intervals from the dosed lake showed a constant level of elevation. Gene expression in the 2001 fathead minnow deployment study was detected within 24- hrs after deployment of control fish into the treated lake and stayed elevated for the entire 13-day study. Highly variable gene expression was found in fathead minnow fry exposed to dosed lake sediments but no significant gene expression was found in fry exposed to reference lake sediments. Male adult fathead minnows exposed to sediment elutriates from sediments collected in 2004 in the previously dosed lake showed significant vitellogenin gene expression. Results indicate that RT-PCR analyses of total RNA can be used to provide a rapid and timely estimate of exposure to estrogenic substances. This study was done in collaboration with Drs Karen Kidd, Vince Palace, Bob Evans and Paul Blanchfield of the Canadian Division of Fisheries and Oceans at the Experimental Lake Area in Ontario, Canada. One presentation will be made at the November 14-18, 2004 Annual Meeting of the Society of Environmental Toxicology and a Manuscript is expected Research Approach Results and Impact Research Collaboration and Research Products ------- Future Research NERL will continue research on EDCs in Wastewater treatment Plant effluents and in Receiving streams and lakes in the U.S. using the Vitellogenin Gene expression assay. Contacts for Additional Information Questions and inquiries can be directed to: James M. Lazorchak U.S. EPA, Office of Research and Development National Exposure Research Laboratory Ecological Exposure Division 26 West Martin Luther King Dr Cincinnati, Ohio Phone: 513 569 7076 E-mail: lazorchak,jim@epa,gov Funding for this project was through the U.S. EPA's Office of Research and Development, National Exposure Research Laboratory, and the work was conducted by the Ecological Exposure Research Division. ------- |