W3 PM Biomarkers
Wednesday, 16 November 2005: 1:50 PM - 5:30 PM in Ballroom 3

(OTT-1117-555350) Watershed-scale application of biomarkers to assess contaminant exposure in largemouth bass.

Otter, R¹, Schreiber, E¹, van den Hurk, P¹, Klaine, S¹, ¹ Clemson Institute of Environmental Toxicology, Pendleton, South Carolina, USA

ABSTRACT- Ecological risk assessment is a process that evaluates the likelihood that adverse effects may occur or are occurring as a result of exposure to one or more stressors. A watershed approach to ecological risk assessment provides a spatial assessment that includes exposure to multiple stressors. U.S. EPA has a framework for the assessment of watersheds that looks for cumulative impacts on an entire watershed instead of the historic site specific or point source approach. This study investigated the use of sub-lethal biochemical responses or biomarkers in fish as tools to evaluate watershed health. The Reedy River watershed, South Carolina, USA is known to have high concentrations of Polyaromatic Aromatic Hydrocarbons (PAHs) and metals. Largemouth bass (Micropterus salmoides) were sampled from three lake sites in the Reedy River, and two reference sites outside the watershed. Metallothionein (MT), 7-Ethoxyresorufin O-deethylase (EROD), aminolaevulinic acid dehydratase (ALAD), bile fluorescence (BF), and histological assays were performed on each fish to determine exposure. PAH and metal analysis (Cu, Cd, Zn, Pb, Cr, Mn, Ni, As, Se, and Ag) were performed on sediment and water from each sampling location to see if correlations between biomarkers and sediment/water samples were possible. Both biological and chemicals samples were taken over multiple seasons and showed varying degrees of seasonal variability. Correlations between biomarkers and sediment/water samples suggested that PAHs were bioavailable; lack of correlation between biomarker and chemical endpoints for metals indicated they were not bioavailable. Results of this study suggest that biomarkers may be a better indicator for exposure characterization.

Key words: biomarkers, PAH, metals, largemouth bass