Baseline study on the levels of organic pollutants and heavy metals in bivalves from the Morrocoy National Park, Venezuela

The concentrations of a range of organic contaminants (aliphatic hydrocarbons, PAH, chlorinated pesticides and PCB) and heavy metals (cadmium, chromium, copper, nickel, lead and zinc) in the flat tree-oyster (Isognomon alatus) from the Morrocoy National Park were determined in order to establish a baseline reference for future monitoring. Most of the Park comprises aquatic habitats such as mangrove forests, seagrass beds and coral reefs. The hydrocarbon load in the samples was dominated by fossil fuel components, probably derived from marinas and recreational boating activities. Poor water circulation seemed to enhance the bioavailability of petroleum hydrocarbons to the tree-oysters. Chlorinated hydrocarbons were detected at very low concentrations. Metal concentrations were also low, with the exception of nickel; a petrochemical complex in the Golfo Triste area is a possible source of the nickel.