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Assessment of exposure of fish to emerging contaminants in the Eagle Creek Watershed
Citation:
BENCIC, D. C., A. ALWAN, J. DORKIN, A. D. BIALES, R. W. FLICK, A. BATT, L. Tedesco, AND J. M. LAZORCHAK. Assessment of exposure of fish to emerging contaminants in the Eagle Creek Watershed. Presented at SWIMS Conference, Chicago, IL, February 09 - 11, 2009.
Impact/Purpose:
The objective of this research was to use ibological (molecular indicators) and chemical (analytical chemistry) endpoints to assess the extent of emerging contaminants in ECW and determine the potential exposure to aquatic life. Adult male fathead minnows (FHMs) were deployed for 7 days in small submerged cages at five sites within ECW. Two consecutive, but independent week-long deployments occurred during high water flow (May-June 2008) and again at the same sites during low water flow (September 2008). Liver, brain and testis tissues were collected from each fish following deployment, as well as from 8 time zero control fish. Site- and seasonal-specific responses to biologically-available environmental estrogens were identified using quantitative, real-time PCR assay for vitellogenin gene expression. Unique liver protein profiles were identified in FHMs from selected sites examined from the spring deployment using two-dimensional polyacrylamide gel electrophoresis. For ehcmical analysis, one liter water samples were collected at each site before and after each deployment and examined for the presence of 54 prioritized human and veterinary pharmaceuticals, with up to half of the tested pharmaceuticals present at selected sites. By identifying previously unknown stressors, these molecular and chemical data promise to aid in targeting source reduction efforts and improving biological diversity.
Description:
The Eagle Creek Watershed (ECW) encompasses 162 square miles in central Indiana upstream of the Eagle Creek Reservoir, a public drinking water source for the city of Indianapolis. The dominant land-cover is agriculture, although some portions are undergoing urbanization, with three majro wastewater treatment plants (WWTPs) and numerous chemical plants and animal feedlot operations in the watershed. Water quality monitoring data collected over the last 20 years indicate that both the reservoir and much of the watershed have not met their designated use criteria. Local organizations such as the Eagle Creek Watershed Alliance have made significant advances in identifying and implementing solutions to problems within the watershed. However, despite the extensivechemical sam;ling, the problems that have been identified to date do not fully explain the fair to poor fish and benthic community assessments. Therefore, it was hypothesized that previously undetected/undetermined emerging contaminants frompoint and/or nonpoint sources may be significant contributors to the poor water quality and reduced fish and benthic community assessments of the watershed.