Radionuclide contamination in Canada: A scoping review

Radionuclides were first discovered in the late 1800s, and artificial (anthropogenic) radionuclides in the 1930s. Since then, this group of substances has been increasingly incorporated into various peaceful and non-peaceful applications across Canada and the world, bringing with it both advanced technological and medical benefits, and public concern about the dangers from radiation exposure. As such, a breadth of research on, and monitoring of, radionuclides in the Canadian environment has been generated, the results of which span decades. However, a recent comprehensive review of these is not readily available. This study aims to fill this gap by synthesizing available literature from the last 30 years on the Canadian state and provenance of radionuclide contamination to better understand the context of overall sources and status of contamination. The findings indicate that while regional and temporal variations exist, on average, routine radionuclide exposure in Canada is generally attributed mainly to natural sources and fallout from historical nuclear weapons testing and nuclear accidents (including the Chernobyl and Fukushima power plant accidents) and to a smaller degree to emissions from nuclear facilities, including active and historical uranium mines and mills, nuclear research facilities, and nuclear power plants. Levels of anthropogenic radionuclides in the Canadian environment have declined since the initial cessation of nuclear weapons testing in the 1960s and are generally below guidelines protective of human health. On the national scale, present-day nuclear sector facilities do not appear to be a significant source of routine anthropogenic, nor technicallyenhanced naturally occurring radionuclide exposure, though local scenarios may vary. These findings contribute context for evaluating the sustainable management of nuclear technologies, radioactive materials and waste in Canada and globally, in line with UN Sustainable Development Goal 12 and target 12.4: responsible management of chemicals and waste.