POLYCYCLIC AROMATIC HYDROCARBON CONTAMINATION IN MARINE-SEDIMENTS NEAR KITIMAT, BRITISH-COLUMBIA

Polycyclic aromatic hydrocarbons (PAHs), like many other hydrophobic o rganic contaminants, are rapidly sorbed to particles and incorporated within sediments in aquatic systems. The PAH composition within the se diments reflects the source(s) from which the PAHs were derived. Howev er the ''source signature'' may be altered by postdepositional weather ing or biodegradation. In the present study, variation in PAH composit ion was investigated in size-fractionated sediments and depth-fraction ated sediments collected from a Canadian fjord contaminated with alumi num smelter derived PAHs. Multivariate analyses of PAH compositional d ata consistently showed that different sampling sites could he discrim inated on the basis of their PAH composition, but smaller versus large r size fractions within a site could not. The composition of unsubstit uted and alkyl-substituted PAHs in a sediment core primarily showed ch anges with depth that were attributable to enhancement of anthropogeni c inputs in the upper core segments. No trends with sediment depth, as sociated with compound-specific weathering or biotransformation, were noted in the composition of anthropogenically generated PAHs. This may indicate a limited chemical and biological availability of the alumin um smelter derived PAHs.