The Nuclear Task Force of the International Joint Commission, United States and Canada, has prepared a document, " Inventory of Radionuclides for the Great Lakes ." This report uses a material balance approach to describe the quantities and composition of reported releases of radionuclides to air and water, and the distribution of these nuclides in atmospheric, aquatic and biotic compartments of the ecosystems of the Great Lakes. The material balance approach is a first step in establishing the sources, pathways, distributions and movements of radionuclides for the purposes of making specific assessments of human and ecosystem exposure, and undertaking risk assessments from the exposure information.

        The primary anthropogenic source of radionuclides is the discharge from nuclear fuel cycle facilities in the Great Lakes region. The contribution of radioactive debris from the atmospheric testing of nuclear weapons has decayed sufficiently in the thirty five years since the Limited Nuclear Test Ban Treaty (1963) that it is a major source only in areas not currently receiving discharges from nuclear facilities. Other sources which use radionuclides are commercial, industrial, medical and research institutions. These sources use very small quantities of radioactive materials, but the very large number of such sources may make, in the aggregate, a significant contribution to the burden of radioactive materials in the environment.

        The Task Force has concluded that monitoring of radionuclides in the Great Lakes primarily meets the need for compliance by users of radioactive materials with the conditions of the licenses for discharge. This results in differences in the radionuclides reported, how radionuclide levels in the environment are reported, the extent of off-site monitoring, and the specific biological compartments included in monitoring by facilities in Canada and the United States. Very little of the monitoring activities are designed to address or are capable of considering the movement and cycling of radionuclides through environmental compartments and ecosystems. Nevertheless, this report begins to consider in a systematic but limited way the cycling of radionuclides through biota. A revised monitoring and analytical protocol with emphasis on biouptake characteristics, physiological roles and impacts would greatly help in meeting the goals and objectives of the Great Lakes Water Quality Agreement of 1978, as amended by the Protocol of 1987.