Remediating While Preserving Wetland Habitat at an LLR Waste Site in Canada

The Low-Level Radioactive Waste Management Office was established in 1982 to carry out the federal government’s responsibilities for low-level radioactive (LLR) waste management in Canada. The Office operates programs to characterize, delineate, decontaminate and consolidate historic LLR waste for interim and long-term storage. In this capacity, the Office is currently considering the remediation of 9,000 cubic metres of contaminated sediment in a coastal marsh in the context of a major remediation project involving multiple urban sites. The marsh is situated between the Lake Ontario shoreline and the urban fringe of the Town of Port Hope. The marsh is designated a Cattail Mineral Shallow Marsh under the Ecological Land Classification system for Southern Ontario and was recently named the A.K. Sculthorpe Marsh in memory of a local community member. The marsh remediation will therefore require trade offs between the disruption of a sensitive wetland and the removal of contaminated sediment. This paper discusses the issues and trade-offs relating to the waste characterization, environmental assessment and regulatory findings and thus the remediation objectives for the marsh. Considerations include the spatial distribution of contaminated sediment, the bioavailability of contaminants, the current condition of the wetland and the predicted effects of remediation. Also considered is the significance of the wetland from provincial and municipal regulatory perspectives and the resulting directives for marsh remediation.