The distribution of polycyclic aromatic hydrocarbons in surficial sediments of Sydney Harbour, Australia

Surface sediment was collected from 124 sites in Sydney Harbour and analysed for the 16 polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants by the US EPA, as well as 2-methylnaphthalene. PAH concentrations varied widely, from < 100 to 380000 pg kg-1 of total PAH. The spatial distribution of PAHs suggested that they derive predominantly from urban run-off. However, discrete point sources of PAH appear to exist at several sites. The relative abundance of individual PAH compounds was remarkably consistent throughout the harbour and indicated that high temperature combustion processes are the predominant source of PAH contamination in Sydney Harbour. Comparison with numerical effects-based sediment quality guidelines derived in the US indicated that most of the sites studied in Sydney Harbour (89%) have levels of PAH which are predicted to either occasionally or frequently result in adverse biological effects.