Trends in sediment quality in Hamilton Harbour, Lake Ontario

Bottom sediment quality in Hamilton Harbour was assessed as part of a long-term research and monitoring program over a period of three decades in order to support remedial activities. Sampling locations reflected a range of shoreline activities and sources of chemical contamination to the harbour. An assessment of temporal trends in metals, polycyclic aromatic hydrocarbons and polychlorinated biphenyls indicate that concentrations of all three classes of contaminants have decreased in sediments in most areas of the harbour since the period 1990–2000; however, the Windermere Arm area impacted by historical industrial activities along the southeastern shoreline area of the harbour was an exception, as trends in some metals and polychlorinated biphenyls showed overall increases. Assessment of spatial distributions of contaminants and the associated polycyclic aromatic hydrocarbon and polychlorinated biphenyl profiles showed that Randle Reef and Windermere Arm continue to be significant contributors to harbour-wide contamination by polycyclic aromatic hydrocarbons and polychlorinated biphenyls, respectively. Continuation of the program after remedial activities should provide an assessment of the overall efficacy of management actions to improve environmental quality in Hamilton Harbour.