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Mytilus edulis were collected intertidally from three locations in Halifax Harbor, Nova Scotia, on five occasions during spring and summer 2000. Bioindicators of health (lipid content), condition and gonad indices (CI and GI), and sex ratio, as well as vitellins, were compared with the bioaccumulation of polycyclic aromatic compounds (PACs) including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), coprostanol, and metals. Twice as many male as female mussels were collected from a downtown site (M8) close to numerous raw sewage effluents and a naval dockyard. Males from M8 had a high lipid content, and females had a delayed production of vitellins. These mussels also displayed the highest levels of PACs, coprostanol, Ag, and Sn. Coprostanol and silver are sewage markers in sediments, and their presence in mussels confirms exposure to sewage effluents. Female mussels were more abundant in an area outside the industrialized part of the harbor that had higher marine traffic (M14); displayed higher levels of vitellins in gonads; had similar time trends for CI and GI; and had some similar metals compared with mussels from M8. The lowest variability in biomarkers was observed at a site in a mostly residential arm of the harbor (M12), which was expected to be more pristine based on an earlier investigation. Compared to mussels in M14, the mussels of M12 had the lowest condition indices and PCB concentrations and low but similar levels of lipids, PACs, and coprostanol. They also displayed the highest concentrations of Cd, Cu, Pb, and Hg, and females had the highest gonad indices early in the season.

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ABSTRACT1. Wastes from feed and faeces can result in the deposition of contaminants in sediments around aquaculture sites. Five types of feed pellet, a commercial fish oil and 76 sediment samples collected under and up to 100 m away from salmon aquaculture cages in the south-western Bay of Fundy between 1998 and 2000 were analysed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and chlorinated pesticides.2. Five alkylated naphthalenes (aNAs) were consistently detected in fish oil (116-180 ng g À1 , per aNA), in pellets (25-51 ng g À1, dry weight, per aNA), and sediments (51-45 ng g À1 , dry weight, per aNA). Other PAHs were detected at variable levels in feed or in sediments.3. IUPAC congener 153 (a PCB) and p,p 0 -dichlorodiphenyldichloroethylene (p,p 0 -DDE) were detected more frequently than other chlorinated targets in oil (108 ng g À1 and 176 ng g À1 respectively), feed (51-14 ng g À1 and 1.7-28.2 ng g À1 respectively) and sediments (50.08-3 ng g À1 and 50.5-7 ng g À1 respectively). 4. Trends were observed during the first year of sediment sampling (1998), with higher organic carbon, PCBs and p,p 0 -DDE levels below the cages than 50 m away. The PAHs other than aNA showed an opposite trend with distance. In 1999, levels of p,p 0 -DDE and PCBs were somewhat reduced under the cages, but were detected up to 100 m away from the cages.5. Levels of aNA tended to be higher at some sites in 1999 relative to 1998, reflecting variability in feed and/or differential transport or degradation of contaminants relative to the environmental background. When detected, mean levels of PCBs and DDE were 2-10 times lower in 2000 than in 1999, and PAHs were 30-40% lower in 2000 than in 1999.6. Interpretation of the results is done cautiously, since the exact locations of the sites sampled is only known to an intermediate facilitating the work between farmers and scientists. Levels of contaminants are compared with international results, interpreted relative to potential toxicity, *Correspondence to: Dr. Jocelyne Hellou, Fisheries and Oceans Marine Environmental Sciences Division, Bedford Institute of Oceanography, 1 Challenger Dr., Dartmouth, Nova Scotia, Canada. E-mail: hellouj@mar.dfo-mpo.gc.ca uptake from feed, from deposited sediments, and in the framework of an aquaculture decisionsupport system published recently.

Surficial sediments and blue mussels (Mytilus edulis) were collected around the perimeter of Halifax Harbour. Samples were analyzed for the presence of polychlorinated biphenyls (PCBs), ranging from mono- to decachloro congeners, and results compared to the presence of polycyclic aromatic compounds (PACs). The objective was to explore the relationship between contaminant profiles in sediments and in mussels, and the possibility of deducing their sources, patterns of deposition, circulation and bioavailability. IUPAC hexachlorobiphenyls 138/158/160/163 (unresolved) and 153/132/168 were the most abundant congeners in both sets of matrices, ranging in concentration between <0.5 to 46 and 4.5 to 25.5 ng/g (dry weight) in sediments and mussels, respectively. PCBs profiles point to a combination of commercial sources superimposed on some weathering. Biota-sediment accumulation factors (BSAF, concentration in mussels, dry weight/concentration in sediments, dry weight, and lipid/TOC normalized) varied throughout the harbour and per congener. Some similarities were observed between the most contaminated sites previously analyzed for PACs and presently analyzed for PCBs, while BSAF were highest at the entrance to the harbour, for PACs and PCBs.