Organochlorine compounds in oysters and sediments from coastal lagoons of the Gulf of Mexico

Concentrations and distributions of selected chlorinated pesticides in 3 coastal lagoons in the south-eastern Mexico gulf were monitored. The lagoons were of particular ecological importance in relation to the production and harvesting of oysters, clams and shrimps. Pesticide concentrations significantly exceeded those previously found to harm organisms inhabiting estuaries. Highly toxic chlorinated pesticides with high persistence were also found. Despite the banning of heptachlor, dieldrin, aldrin and endrin and severe restrictions on DDT, lindane and HCH in Mexico, most of these compounds were detected in lagoon waters.