Biomarkers of PAH Exposure in Livers and Bile of Reef Fish From Northern Gulf of Mexico After the Deepwater Horizon Oil Spill

The Deepwater Horizon Oil spill released almost 5 million barrels of crude oil into the Gulf of Mexico in 2010. Crude oil contains toxic components including polycyclic aromatic hydrocarbons (PAHs) that may harm aquatic organisms. Fish accumulate and metabolize PAHs, which can result in cancer or other negative health effects.  Cytochrome P450 1A (CYP1A), part of the mixed function monooxygenase system is induced by PAH exposure and metabolizes PAHs and other xenobiotics.  CYP1A activity which can be measured by 7-ethoxyresorufin o-deethylase (EROD) and Glutathione-S-transferase (GST); biomarkers of phase I and phase II metabolism. Superoxide Dismutaste (SOD) is a biomarker of antioxidant defense and measures oxygen radical scavenging. Fish exposed to oil should exhibit increased EROD activity, which serves as a biomarker of oil exposure and toxic effect.  Over 500 fish, including Lutjanus campechanus (Red Snapper), Balistes carolinensis (Grey Triggerfish), Pagrus pagrus (Red Porgy), and Seriola fasciata (Amberjack) were collected from multiple offshore locations along the Gulf of Mexico off Alabama and Florida in 2010-2011, during and after the oil spill. Livers were collected and frozen (-80ºC) until analysis.  Using this data to evaluate spatial and temporal trends and interspecies differences in response to the Deepwater Horizon oil spill, we measured EROD, GST, and SOD activity. Bile PAH concentrations were also measured in the same fish to link EROD activity to PAH exposure.