Pesticide and trace metal concentrations in Queensland estuarine crabs

Trace metals, metalloids and pesticide content were quantified in intertida l burrowing crabs Australoplax tridentata and a portunid Scylla serrata sam pled from estuaries on the east coast of Australia between Cairns and Brisb ane, Residues of dieldrin occurred at all locations, heptachlor epoxide and DDT (principally metabolites DDD and DDE) at most, reflecting historical u se. Chlordane, chlorpyrifos and endosulfan were only detected in crabs in t he urban Brisbane area, and neither hexachlorobenzene (HCB) or polychlorina ted biphenyls (PCBs) were quantifiable, Calculations of ambient exposures t o organochlorines based on residues in crab tissues indicated that dieldrin exceeded national water quality guidelines for protection of aquatic ecosy stems at all sampling locations, but exposure to DDT and its metabolites wa s below the threshold of concern. Concentrations of trace metals and metall oids generally reflected sediment data and likely sources. (C) 2000 Elsevie r Science Ltd. All rights reserved.