Development of cleanup criteria for historic low-level radioactive waste sites in Canada

This paper will describe recent work performed to develop cleanup criteria, and their current status, for historic low-level radioactive waste sites in Canada. These historic wastes date back to 1933, when a radium refinery began operation in Port Hope, Ontario. The problem of residual wastes and contaminated buildings and soils in Port Hope, resulting from the practices in the early years of radium and uranium production, was discovered in the mid-1970s, and a large scale cleanup program carried out. This work was concentrated on developed properties. As a result, substantial quantities of contaminated materials remained in a number of large undeveloped areas. A number of additional historic waste sites have subsequently been discovered at other locations in Canada, where buildings and/or soils were contaminated with uranium ores or concentrates spilled during transport, or with processing residues, or as a result of the use of radium containing materials. There has been substantial evolution of the criteria for cleanup of these sites over the almost 20 year period since work started at the first sites