Historical Monitoring of Biomarkers of PAH Exposure of Brown Bullhead in the Remediated Black River and the Cuyahoga River, Ohio

Abstract

Biomarkers of exposure to chemical contamination, benzo[a]pyrene (BAP)- and naphthalene (NAPH)-type metabolites, were measured in brown bullhead from a heavily polycyclic aromatic hydrocarbons (PAHs) contaminated section of the Black River, Ohio, during and immediately after remedial sediment dredging in 1990–1991, and in follow-up revisits in 1993 and 1998. Biomarker levels of bullhead from the historically polluted Cuyahoga River and the protected Old Woman Creek National Estuarine Sanctuary in Ohio were also measured over the same time periods. PAH-bile metabolite concentrations of bullheads from the Black River were still elevated in the year following dredging, but were significantly lower in the later resampling years. Metabolite concentrations of Cuyahoga River bullhead decreased significantly between 1991 and 1993, possibly in response to the shutdown of coking operations on the river. Fish from Old Woman Creek showed some variation in metabolite concentrations among periods, but were consistently lower than the other two rivers at each time. Measurement of bile metabolites proved an effective tool for estimating changes in exposure over time and among sampling sites. Trends in biomarkers indicated lowered exposures in the Black and Cuyahoga Rivers. These findings are likely a result of remediation activities in the Black River and source reduction and incidental sediment displacement in the Cuyahoga River.