Great Lakes sediments and biota are contaminated by persistent and toxic organochlorine compounds. Large areas of sediments are contaminated, however, much higher concentrations are observed in fish and birds due to bioaccumulation processes The estimated total load of polychlonnated biphenyls in the sediments of the Lakes Ontario, Erie and Superior is approximately 50 metric tons. Spatial and temporal changes of sediment contamination can provide useful information on contaminant sources and pathways within the basin.
With increasing numbers and amounts of chemicals in use, the potential for further environmental damage is high. Environmental research, effluent limitations and public education are needed to restore and maintain high water quality in the Great Lakes.