Polynuclear Aromatic Hydrocarbons in American Oysters Crassostrea virginica from the Terminos Lagoon, Campeche, Mexico

The concentrations of polynuclear aromatic hydrocarbons in oyster tissues from one of the most productive shrimp-fishing and oyster-farming areas in the coastal Gulf of Mexico, the Terminos Lagoon, were measured to assess the impact that offshore crude oil production on the continental shelf of Campeche might have on local resources. Total PAH concentrations in oyster tissues ranged from 2470 to 42,500 ng/g during this six-month study. The predominance of low and medium molecular weight alkylated compounds over their parent compounds indicates the petrogenic source of these PAHs. The apparent correlation between the geographical distributions of the measured PAH concentrations and the distinctive circulation pattern into and inside the lagoon suggests that offshore oil activities are the source of these PAHs to local oysters. Although comparable, the concentrations reported in this study are on the high side of those reported earlier in samples from the same general area and from the northern coast of the Gulf of Mexico. This should be a cause for concern in a protected area where oysters are farmed for human consumption and should result in the implementation of monitoring programs.