Year Established: 2011 Start Date: 2011-03-01 End Date: 2012-02-29
Total Federal Funds: $20,000 Total Non-Federal Funds: $40,000
Principal Investigators: Robert Bringolf, Cecil Jennings, Jeffrey Zuiderveen
Abstract: Recent reports of intersex fish in water bodies around the world (including Georgia) have stimulated widespread concern about the effects that chemicals are having in the environment. Intersex is a term used to describe the presence of both male and female characteristics in individual fish, most commonly, the presence of oocytes (eggs) in testicular tissue, a pathological condition that is not routinely observed in most fish species. The intersex condition has frequently been associated with a component of municipal wastewater effluent and this condition has been demonstrated to reduce reproductive fitness, i.e., intersex fish have been shown to have decreased sperm (milt) production, decreased sperm motility and decreased fertilization success compared to histologically normal male fish. These findings generate numerous questions about the ecological ramifications of intersex fish and have human health implications as well. We have recently begun the first systematic evaluation of the severity and extent of the intersex condition in fish in Georgia as well as possible causes. Preliminary results indicate that intersex is prevalent in some lakes and rivers across the state. Analyses to quantify chemicals that may be causing this condition are in process. Preliminary results from our lab studies suggest that water temperature during early life stages plays a critical role in reproductive fitness later in life but this potentially key novel finding (for freshwater fish) requires further investigation. Our objectives for 2011 GWRI funds are to: (1) expand sampling efforts for fish from additional rivers and lakes across Georgia; (2) expand sampling efforts to determine levels of estrogens in water samples collected throughout Georgia; (3) determine the influence of temperature during early life stages on reproductive fitness later in life. In 2010 we collected water samples and 132 black bass (largemouth, spotted, redeye, and shoal) from 4 rivers and 6 lakes across Georgia. We propose expanding sampling sites to include at least 3 other major rivers of the state including the Flint River, Chattahoochee River, and Conasauga River as well as additional lakes and ponds from across the state. Water samples and fish will be collected at each site. Fish gonads will be examined for evidence of the intersex condition. Estrogenic potency of Georgia's surface waters will be determined with the yeast estrogen screen (YES), a reporter gene assay in which yeast cells have been transfected with human estrogen receptors and enzymes. We will use the YES assay to quantify the seasonal and spatial variation in estrogenic potency of Georgia waters from across the state where fish have been collected for intersex evaluation. The goal of the proposed work is to complete the first systematic characterization of the estrogenic activity in Georgia waters and the incidence of intersex in fish across the state. This project will help us better understand the extent to which estrogens and intersex fish are distributed in surface waters throughout Georgia and the Southeastern U.S. This study will provide the first investigation of estrogens in Georgia's surface waters and intersex fish in many of Georgia's rivers and lakes. The results are crucial for understanding the spatial and temporal distribution of estrogens in surface waters, particularly those receiving substantial municipal wastewater effluent. Use of the YES assay to detect estrogenic compounds in water will allow us to determine which areas of the state are most impacted by estrogens and guide future research. Environmental scientists and resource managers from other states in the Southeastern U.S. have expressed interest in our approach which may become the model for a larger, region-wide sampling effort that will likely attract substantial grant support from federal and state sources.