1.1    Mandate of Task Force

    In 1995, the International Joint Commission (hereafter: the Commission or IJC) authorized a "Nuclear Task Force" (hereafter: the Task Force) to review, assess, and report on the state of radioactivity in the Great Lakes and to carry out such other activities as the Commission might, in future, so direct. As an initial project, the Commission requested a review and assessment of the status of radioactivity in the Great Lakes. That project had a completion time within the 1995-1997 biennial Great Lakes reporting cycle. In addition, the Commission authorized the Task Force to recommend additional projects based in part on the following criteria:

(a) Work performed in the preparation of the report on the state of radioactivity in the Great Lakes. The Task Force would use this report as the principal vehicle upon which to base recommendations for various projects. An objective of the report was the prioritization of nuclear problems in the Great Lakes requiring analysis and remediation.

(b) Concerns of the Commissioners.

(c) Problems brought to the attention of the Task Force by its Members, Associates, and others in the course of its work.

    The Commission requested that the Task Force make its first official recommendation of additional projects upon the completion of work for its first assessment of the state of radioactivity in the lakes. Further, the Task Force shall undertake such other projects as the Commission directs and shall seek from the Commission directly whatever resources and funds are needed for specific projects and support. This report responds to the mandate set forth by the Commission in 1995.

    The Task Force determined that an "Inventory of Radionuclides" for the Great Lakes was an essential project to address the "state of radioactivity" in the Lakes. Following that decision, the Task Force undertook a study to produce such an inventory. This report results from that work.


1.2    Scope of the Inventory

    An inventory of radionuclides for the Great Lakes attempts to quantify and organize the information on the sources, levels, distributions, receptors, and repositories of radioactivity in the Great Lakes Basin (hereafter: Basin). It is the numerical part, but not a theoretical modeling simulation, of a material balance of radioactive substances found in the Great Lakes.

    The Commission's Great Lakes projects derive from an international agreement between the United States and Canada called the "Great Lakes Water Quality Agreement" (hereafter: the Water Quality Agreement or Agreement; IJC 1987 a ). The Agreement contains a "specific objective" (numerical environmental criterion) for radioactivity. In the 25 years of the Agreement's existence, neither this objective nor the subject of radioactivity itself drew much Commission attention. With the impending decommissioning of nuclear power plants, the growing problems of nuclear waste, and the signing of a Comprehensive Test Ban Treaty on 24 September 1996, posing a plutonium disposal problem, general concerns about the effects of radioactivity on humans and ecosystems have made the subject of radioactivity very timely.

    The Agreement also espouses an "ecosystem approach," which the Task Force has used to place in perspective the extent to which radionuclides may be environmental factors in the dynamics of Great Lakes ecosystems. This ecosystem approach requires, where possible, an estimation of the radioactivity stored in Lake biota, sediments, and the water column.

    An inventory is a natural starting point to evaluate many of the issues of radioactivity. It basically organizes the information on what exists and where it exists. Without an inventory, the basic analysis of risk assessment cannot be performed, nor can one determine which aspects of sources, distributions, and pathways of radionuclides require special attention. The Commission recognized the fundamental importance of an inventory and authorized the Task Force to develop this tool.


1.3    History

    From 1945 to 1963, radioactive fallout from the atmospheric testing of nuclear weapons was the main source of artificial radioactivity to the Great Lakes. Starting in 1963, the commissioning of the reactors at nuclear power plants in the Basin added new sources of artificial radioactivity to the Great Lakes. Following the Limited Test Ban Treaty in 1963, atmospheric testing of nuclear weapons continued sporadically through 1980. Simultaneously, the number of nuclear power plant facilities in the Great Lakes region increased rapidly until 1974 then more slowly until 1993. There are 11 nuclear power plants with 16 reactors in the United States portion of the Basin and 4 nuclear power plants with 21 reactors in the Canadian portion of the Basin, all with emissions to the Basin. Two other nuclear power plants operate in Great Lakes states near the Basin, but their emissions enter other watershed and airshed regions. During the 30-year period of the Limited Test Ban Treaty, the decay of residual nuclear debris from atmospheric testing has reduced nuclear fallout sufficiently to make it a secondary source of artificial radioactivity to the Great Lakes.

    Other large source of radioactivity in the Basin include the following: a tritium removal plant at Darlington, uranium mine and mill tailings that enter the Serpent River Region, uranium refining and conversion at Blind River and Port Hope, and weapons facilities and auxiliary operations at Ashtabula. Not all of these facilities are currently operating, but they remain sources of radioactivity to the Basin. There is some question as to whether facilities at Fernald (Ohio) can produce emissions that reach the Basin directly. The Task Force notes that this facility is sufficiently close geographically to the Basin to consider it as a possible source.

    Previous Commission reports from 1977 to 1987 (IJC 1977, 1983, 1987 b ) have reviewed radioactivity in the Great Lakes Basin, specifically those of the Great Lakes Water Quality Board (hereafter: GLWQB). These reports discussed the routinely studied radionuclides: tritium ( 3 H), strontium ( 90 Sr), cesium ( 137 Cs), radium ( 226 Ra), uranium ( 238 U), and iodine ( 131 I); total , , and radiation; and a few occasionally reported radionuclides: antimony ( 125 Sb), cobalt ( 60 Co), and thorium ( 232 Th). The past reports can help to address the amount of the radioactivity in the Great Lakes, but they are an inadequate basis for addressing such issues as ecosystem impacts of radioactivity, the technology and resource needs for nuclear waste isolation, the decommissioning of nuclear reactors, and interactions of toxic chemicals and radiation in the ecosystem.


1.4    Exclusion of direct cosmic and terrestrial radiation

    The Task Force did not consider the radiation associated with direct cosmic ray bombardment, except where such radiation produces cosmogenically important background radionuclides. Thus, the Task Force did not consider the problems of solar flux, UV-B radiation, and similar topics as these radiations are non-ionizing and pose a different set of problems from those of radionuclides. Further, the Task Force omitted the natural production of radon gas a decay product of radium in undisturbed rock and soils. Rather, the Task Force addressed the subject of radon gas in its consideration of radionuclides produced in the nuclear fuel cycle, under the topic of uranium mining and milling and fuel processing.


1.5    Acknowledgments

    The Task Force used only data from open and public sources, including recently declassified documents from the atomic energy authorities in Canada and the United States. When the Task Force learned that some data were "Proprietary," it sought the permission for use of the data from its holders. The Task Force gratefully acknowledges the providers of data and many persons who assisted in its acquisition and use. In particular, the Task Force thanks Messrs. Paul Gunter and Marcel Buob of the Nuclear Information Resources Service (NIRS) for compiling and organizing the data on nuclear facility licenses, emissions, and monitoring protocols from the files in the reading room of the United States Nuclear Regulatory Commission (NRC); Mr. Michael Petko of the United States Environmental Protection Agency (EPA) for supplying the reports of the Environmental Radiation Monitoring System; Dr. Lester Machta of the National Oceanic and Atmospheric Administration (NOAA) for supplying several special reports from the National Council on Radiation Protection (NCRP); Mr. William Condon of the New York State Department of Health, Bureau of Environmental Radiation Protection, for supplying the annual reports of his organization; Ontario Hydro for permission to access and use proprietary data from its monitoring and surveillance reports and other documents related to nuclear power generation in Ontario; the Atomic Energy Control Board (AECB) of Canada for assistance in obtaining information on the use of radionuclides by hospitals and commercial entities in Ontario; the reference librarians at the AECB library in Ottawa for patiently assisting us with various reference tasks; Dr. Ursula Cowgill for assistance in analysis and understanding of the data on elemental cycling in plants and animals; Dr. David Edgington for assistance in analyzing inventories for transuranic elements; Mr. Paul Payson for his excellent work in editing this report and last, but never least, the indefatigable and dedicated assistance of Ms Émilie Lepoutre, who served as the Task Force's secretary, assistant, telephone operator, and good friend.


1.6    Stylistic Conventions

    The stylistic conventions of the Canadian National Research Council's Research Press have been followed as closely as possible in the preparation of this document.