Remediation of former military bases in the Canadian Arctic

This paper describes novel aspects of the remediation of three former military bases in the Canadian Arctic. At Iqaluit, the site has been totally cleaned up. All buildings were demolished, and soils contaminated with metals and polychlorinated biphenyls (PCBs) removed. Soils were excavated and most containerized and shipped south for disposal; soils containing 1–5 ppm PCBs were buried on site along with nonhazardous debris. PCB-contaminated concrete foundations were also investigated and removed. While most contamination was in the surface of the active layer, some migration of PCBs along the surface of the underlying bedrock at greater depth was found. At Sarcpa Lake, a dump leaching PCBs was excavated. Methodology was developed for this investigation and the difficulties of excavation in permafrost are described. The PCBs in the dump were from electrical equipment and/or PCB-containing paint used at this former Distant Early Warning (DEW) Line site. Investigation of the painted material at the site showed PCB levels as high as 7.4% in the paint. Wall swab results show that the repainting of the walls had effectively rendered the PCBs unavailable to solvent washing. At Resolution Island, the extent of contamination is much larger than the other two sites. Interceptor barriers were designed and installed in the leachate pathways carrying PCBs between the site and the ocean. At this site, the presence of petroleum products along the drainage pathway has led to increased transport of PCBs due to their higher solubility in these solvents as compared to water. Current progress at this unique remote site and the options for dealing with the contaminated soil are discussed.