Levels of selected chlorinated hydrocarbons in edible fish tissues from polluted areas in the Georges/Cooks Rivers and Sydney Harbour, New South Wales, Australia

During the period from February to March 1995 edible fish were sampled from various locations known to be polluted with chlorinated hydrocarbons. Samples were collected from five locations in the Georges/Cooks Rivers and four locations in Sydney Harbour. The muscle tissue of a range of fish species from each location was analysed for selected chlorinated hydrocarbons (i.e. polychlorinated biphenyls (PCBs) and organochlorine pesticides). The Georges/Cooks Rivers locations were in Prospect Creek. Chipping Norton, Saltpan Creek, Cooks River and Alexandra Canal. The Sydney Harbour locations were in Duck River, Parramatta River, Homebush Bay, Iron Cove and Long Bay. Chlorinated hydrocarbons were found in the tissues of fish sampled from every location. The major contaminants were PCBs and the Group A organochlorine pesticides, which include chlordane, dieldrin and heptachlor epoxide. At some locations, the mean concentration of one or more of these contaminants was significantly greater than the National Food Authority Maximum Residue Limit (MRL) in certain fish species. DDT and/or its metabolites were not found above their MRL at any location, but were detected at all locations. The highest mean concentrations of PCBs were detected in fish from Prospect Creek, Chipping Norton, Duck River, Alexandra Canal and Homebush Bay. The highest mean concentrations of Group A pesticides, particularly chlordane and dieldrin, were detected in fish from Alexandra Canal, Cooks River and Duck River. The highest mean concentrations of DDT were found in the tissues of fish from Prospect Creek. The fish species which accumulated contaminants to concentrations exceeding the relevant MRLs were yellow-fin bream (Alexandra Canal, Cooks River, Saltpan Creek, Duck River, Homebush Bay and Parramatta River), sea mullet (Prospect Creek, Chipping Norton, Cooks River, Alexandra Canal, Saltpan Creek, Duck River, Homebush Bay and Iron Cove), pink-eye mullet (Prospect Creek) and silver biddy (Prospect Creek, Chipping Norton, Alexandra Canal and Iron Cove), whereas the luderick, fan-tail mullet and sand whiting had mean concentrations of contaminants below the relevant MRLs.