Three former outdoor target ranges, with extensive metals and PAH contamination, were remediated using on-site management strategies including cement-based stabilization, hazardous waste containment, and soil capping. The objectives of the remedial program were to manage contamination in a 1.8-hectare area, to reinstate the area to its original park conservation land use, and to provide a cost-effective solution for limiting the risks to humans and the environment. Cement-based stabilization was used to treat approximately 3,950 cubic metres of soil (derived from focus areas exhibiting high contaminant concentrations, such as target berms and backstops). The on-site landfill was completed with an asphalt surface to serve as the parking lot for the new park. Soil capping was utilized in approximately 4,300 m2 and 4,500m2 portions of the former east and west target ranges, respectively, and was implemented to provide a physical barrier/buffer from contact with the hazardous waste, erosion and drainage control, and act as a chemical fixation. The main challenge of the program was to obtain stakeholder and regulatory approvals to accept this innovative and cost-effective risk-based remedial plan.

Surficial geology of the area consisted of tertiary bedrock including sandstone, siltstone, shale, conglomerate, and minor volcanic rock (Geological Survey of Canada Map 1486A, 1979). In areas where bedrock was not exposed, soils consist of glacial deposits and colluvium. Groundwater generally flows to the northeast while on-site streams carried hazardous waste metals off-site into Burrard Inlet, a large salt waterbody located approximately 300 metres north of the Site.

Contaminants of concern were lead and copper from spent ammunition and polycyclic aromatic hydrocarbons associated with clay pigeon targets. In order for the proposed park development to be in compliance with the Provincial Environmental Management Act (EMA), Contaminated Sites Regulation (CSR), and Hazardous Waste Regulation (HWR), the City of Burnaby initially commissioned a Preliminary Site Investigation (PSI) and a Detailed Site Investigation (DSI) in order to define the nature and extent of the contamination.

Conventional off-Site hazardous waste disposal (i.e. “dig and dump”) methods, involving the excavation and transport of the hazardous waste material to an approved, out-of-province hazardous waste landfill. This process was estimated to cost $3,000,000. Costs for alternate, on-Site remedial management options were estimated at $1,800,000 or 60% of the “dig and dump” costs.

The remedial plan incorporated the existing hazardous waste remain in place since the area was classified as an historical contaminated site. The overall design for the remediation program addressed potential risks associated with the in-situ management, with consideration given to stormwater management, erosion control, geotechnical issues, and the protection of the groundwater and surface water resources. Additional project work included ground contouring/landscaping and the installation of new sediment/drainage control features to handle run-off and drainage in the area of the site.