PCB Contaminated Sediments from Petit-de-Grat, Canada

by S. MacKnight, Ocean Chem Ltd, Dartmouth, NS, Canada,
E. MacLellan, Ocean Chem Ltd, Dartmouth, NS, Canada,

Document Type: Proceeding Paper

Part of: Dredging and Dredged Material Disposal


In Canada, ocean disposal of dredged materials is regulated by the Ocean Dumping Control Act. Included within the schedules of regulated substances are organochlorine compounds, such as PCB's. In 1977, Public Works Canada proposed the dredging of a cove area adjacent to a fish/fish meal processing operation. Sediment concentrations of PCB's in excess of 1000 ng/g were reported. Subsequent surveys further defined and delineated the contaminated area, with concentrations as high as 20,000 ng/g being reported. These can be compared to typical small harbor sediment concentrations of 10-20 ng/g. The proposed material for dredging consisted of two layers: the upper layer, (8% of total volume) comprising decomposed fish wastes and oils was the source of contaminants; the underlying layer (92% of total volume) was a 'clean' glacial till material. The solution to the disposal problem was to suction dredge the fish 'muck' into a containment facility; the underlying till could then be ocean dumped.

Subject Headings: Dredged materials | Ocean engineering | Pollution | Fish management | Dredging | Industrial wastes | Scheduling | Organic compounds | Canada

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