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IDENTIFICATION OF THE CAUSE OF BIOLOGICAL IMPAIRMENT IN THE LITTLE SCIOTO RIVER, OHIO
Citation:
Cormier, S M., E.L C. Lin, M. R. Millward, D. E. Williams, B. Counts, D. Altfater, AND R. Sanders. IDENTIFICATION OF THE CAUSE OF BIOLOGICAL IMPAIRMENT IN THE LITTLE SCIOTO RIVER, OHIO. Presented at Society of Environmental Toxicology and Chemistry, Philadelphia, PA, November 12-14, 1999.
Impact/Purpose:
The purpose of this research project is to provide methods, tools and guidance to Regions, States and Tribes to support the TMDL program. This research will investigate new measurement methods and models to link stressors to biological responses and will use existing data and knowledge to develop strategies to determine the causes of biological impairment in rivers and streams. Research will be performed across multiple spatial scales, site, subwatershed, watershed, basin, ecoregion and regional/state.
Description:
The Little Scioto River in Ohio was selected as a case study for the development of a causal framework which combined measures of community assemblages, habitat quality and biomarkers in an ecological and diagnostic approach. Fish assemblage condition was measured with the Index of Biotic Integrity (IBI), macroinvertebrate assemblage with the Invertebrate Community Index (ICI), and habitat quality with the Qualitative Habitat Evaluation Index (QHEI). Ambient levels of potential chemical stressors were determined from sediment and water chemistry analyses. Exposures to a variety of contaminants were estimated in two fish species, white suckers (Catostomus commersoni) and common carp (Cyprinus carpio) using five biochemical assays. Biomarker levels of fish and index scores from potentially stressed sites were compared with samples taken from upstream "least impacted" sites and with a calculated regional exposure criteria or Ohio's aquatic life use criteria. Longitudinal analysis of community indices showed impairment, physical habitat measurements suggested possible causes, sediment and water chemistry showed presence of contaminants, and biomarkers proved exposure. Characteristics of the fish and macroinvertebrate assemblages were consistent with ecological and biological theory and analogues to biological signatures at other contaminated sites. Responses to two distinct types of stressors, habitat modification and complex toxics, were found. Combining indicators of different types in a causal framework provided more information, and made a stronger case for implied stressor sources than any single indicator.