Pesticide and Trace Metal Concentrations in Queensland Estuarine Crabs

Trace metals, metalloids and pesticide content were quantified in intertidal burrowing crabs Australoplax tridentata and a portunid Scylla serrata sampled from estuaries on the east coast of Australia between Cairns and Brisbane. Residues of dieldrin occurred at all locations, heptachlor epoxide and DDT (principally metabolites DDD and DDE) at most, reflecting historical use. Chlordane, chlorpyrifos and endosulfan were only detected in crabs in the urban Brisbane area, and neither hexachlorobenzene (HCB) or polychlorinated biphenyls (PCBs) were quantifiable. Calculations of ambient exposures to organochlorines based on residues in crab tissues indicated that dieldrin exceeded national water quality guidelines for protection of aquatic ecosystems at all sampling locations, but exposure to DDT and its metabolites was below the threshold of concern. Concentrations of trace metals and metalloids generally reflected sediment data and likely sources.