Risk Estimates: Polycyclic Aromatic Hydrocarbons in Sydney Harbour Sediments and Lobster

Abstract

For nearly a century, the effluents from the Sydney Tar Ponds were discharged into Muggah Creek. As this creek opens into the South Arm of Sydney Harbour, this discharge resulted in appreciable levels of polyaromatic hydrocarbons (PAHs) being deposited in the Harbour sediments. Because surveys showed that lobsters captured in the South Arm of the Harbour contained substantial levels of benzo[a]pyrene, a known carcinogen, the lobster fishery in the South Arm of the Harbour was closed in 1982. Prior to the closure, the cancer lifetime risk for those eating lobsters from this area was approximately 3 times greater than the provincial acceptable level. Following the closure, the lifetime cancer risk declined to levels considered to be acceptable. Computed non-cancer hazards were deemed acceptable prior to the closure and decreased following it. A more extensive risk assessment will evaluate the site further and provide valuable information on fisheries decisions for this area.