Sediments from Lake Conestee, a former reservoir now filled with pollutant-enriched sediments, located south of Greenville, South Carolina, USA, and other nearby reservoirs were collected and analyzed for lead and polycyclic aromatic hydrocarbons (PAHs). Hepatic ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), UDP-glucuronosyltransferase (UGT), sulfotransferase (SULT), and erythrocyte delta-aminolevulinic acid dehydratase (ALAD) were measured in largemouth bass (Micropterus salmoides) to characterize biological effects of these contaminants over three seasons. Results showed that total PAH concentrations in Lake Conestee sediments were significantly greater than the control during each season. An average 10-fold induction in EROD activity was observed at Lake Conestee compared with the control over all three seasons, indicating that PAHs present in sediment were bioavailable to fish. Significant gender effects were observed in EROD activity during the spring, in which activity in reproductively active female fish was significantly suppressed compared with the male fish. Sediments from Lake Conestee had elevated lead concentrations, but the lack of ALAD inhibition in bass indicated that lead was not biologically available. Total GST activity, UGT activity, and SULT activity were not significantly induced in fish from any of the affected sites compared with the reference site. Both EROD and UGT activities were highest during the winter, as were sediment PAH concentrations in Lake Conestee, possibly linked to seasonal resuspension events. The biomarkers measured in this study were useful as a first investigation into the biological effects of contaminant exposure, as well as in determining the bioavailability of contaminants in Lake Conestee.

Biomarkers can be used as tools to help determine ecological exposure in watershed assessments. In the present study, metallothionein and fixed wavelength bile fluorescence for two-, four-, and five-ring hydrocarbons were used as biomarkers of exposure in largemouth bass (Micropterus salmoides) in the Reedy River watershed located in South Carolina, USA. Fish were sampled from three impoundments and a reference site over three seasons in the same year. Biomarker endpoints were compared to chemical concentrations at each site during each season. Results indicated that despite elevated concentrations of hydrocarbons being present in sediments, the hydrocarbons did not appear to be bioavailable based on bile fluorescence analysis. Bile fluorescence analysis also indicated that the hydrocarbons detected in this watershed were likely of petrogenic origin. Significantly elevated sediment concentrations of Cd, Cr, Cu, Pb, Ni, Ag, Zn, and metallothionein were found in one impoundment, Lake Conestee, compared with the reference site, indicating both the presence and bioavailability of these metals. Seasonal variability of bile fluorescence was limited; however, metallothionein showed elevated concentrations in the spring and summer compared with fall.