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COST AND BENEFITS OF ALTERED BENZO(A)PYRENE METABOLISM IN A PCB-ADAPTED FISH POPULATION
Citation:
Nacci, D E., M. Kohan, L Coiro, M C. Pelletier, AND S E. George. COST AND BENEFITS OF ALTERED BENZO(A)PYRENE METABOLISM IN A PCB-ADAPTED FISH POPULATION. Presented at Society of Environmental Toxicology and Chemistry, Nashville, TN, November 12-16, 2000.
Description:
We examined populations of an estuarine fish species (Fundulus heteroclitus) resident to a highly contaminated site and a reference site for their ability to metabolize an important environmental pollutant. In previous work, we characterized the fish population resident to this highly polychlorinated biphenyl (PCB)-contaminated site as genetically resistant to the effects of the most toxic PCBs, categorized as dioxin-like contaminants (DLCs). In DLC challenge experiments, resistant fish survived well and demonstrated altered responsiveness for enzymes regulated via the aryl hydrocarbon (Ah) receptor pathway. While the mechanistic link between DLC-induced health effects and enzyme induction is not well understood, these enzymes are known to be important in the metabolism of another major class of environmental pollutants that act partially through the Ah receptor, polyaromatic hydrocarbons (PAHs). To test how these fish and their laboratory-reared progeny perform upon exposure to PAHs, we conducted challenge experiments using the model PAH, benzo(a)pyrene (BaP). Enzyme inducibility by BaP and rates of BaP-DNA adduct formation were significantly lower in PCB-resistant than PCB-sensitive fish. These results suggest that this DLC-adaptation might provide protection from tumor formation following chronic field exposures to P AHs. However, reduced metabolism could result in reduced elimination of parent compounds. High concentrations of these toxic and photo-active PAHs could have adverse consequences on the health and reproduction of these adapted fish and their progeny. Interpretations of these findings have important implications for our understanding of the relative costs of adaptation to anthropogenic contaminants.