Seasonal and geographical distribution of PAHs in mussels, Mytilus edulis,collected from an urban harbour.

Mytilus edulis were collected intertidally from 16-18 sites located around the perimeter of Halifax Harbour, of an island located at the entrance to t he harbour and from the Northwest Arm. The concentrations of 31 polycyclic aromatic hydrocarbons (PAHs), lipid and moisture content were determined in pools of this filter feeder sampled over three seasons spanning two years, along with calculating individual condition indices. Contaminants were nea rly undetectable in many of the summer mussels and highest in some of the s pring samples. At several sites, the sum of PAHs expressed on a dry or lipi d weight basis, was either equal or higher in April compared to November. F luoranthene was the most predominant PAH followed by pyrene and phenanthren e. At most sites, parental PAHs, associated with combustion sources of cont amination, were more abundant than alkylated derivatives. A larger petroleu m input was noticeable in mussel extracts from sites in close proximity to potential sources.