March/April 1998
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March/April 1998 |
by Murray Clamen and Joel Fisher
Over the years, the manufacture, storage and atmospheric testing of nuclear weapons, the generation of electricity by nuclear power plants, and other human activities have added to the radionuclides that naturally occur in the Great Lakes basin ecosystem. Many potential problems from these artificial sources have been difficult to assess because releases of radionuclides, and their movement through and effects on ecosystems, have not been tracked in a systematic manner.
In the next several years, utility companies in the United States and Canada will begin decommissioning reactors at several nuclear powered electrical generating stations and will address the growing problems of management and disposal of nuclear waste and possible issues of site closure and restoration to non-nuclear uses. We will need a better scientific understanding of the potential effects of radionuclides on human and ecosystem health in the Great Lakes basin to support the decision-making.
In light of present and future information needs, the International Joint Commission (IJC) established a Nuclear Task Force in 1995 to review, assess and report on the state of radioactivity in the Great Lakes basin. One of IJC's responsibilities is to assess efforts to restore and maintain the integrity of the waters of the Great Lakes basin ecosystem under the Great Lakes Water Quality Agreement.
The Task Force examined the available information and recently compiled an Inventory of Radionuclides for the Great Lakes. A material balance approach was used to describe the reported releases of radionuclides to air and water, and how they are distributed in the air, water and living organisms in the Great Lakes basin.
This approach is a first step in establishing the sources, pathways, distribution and movement of radionuclides. The Task Force found, however, that more consistent information must be gathered to provide an adequate basis for determining human and ecosystem exposure, and undertaking risk assessments from the exposure information. Current monitoring is carried out to comply with various discharge licenses and there are many differences in the radionuclides reported by facilities in each country and how levels are measured. The Task Force concluded that a revised monitoring and analytical protocol is needed to more fully assess how radionuclides affect the health of the ecosystem and whether adequate controls are in place o meet the goals of the Agreement.
At present, facilities comprising the nuclear energy fuel cycle are the primary human source of radionuclides in the Great Lakes basin. There are 11 nuclear power plants with 16 reactors in the U.S. portion and four plants with 21 reactors in the Canadian portion, all of which emit radionuclides. Other large sources include, on the Ontario side of the basin, a tritium removal plant at Darlington, uranium mines and their mill tailings that enter the Serpent River region, and uranium refining and conversion at Blind River and Port Hope. In the U.S. there are weapons facilities and auxiliary operations at Ashtabula, Ohio and nuclear fuel facilities in West Valley, New York.
Commercial, industrial, medical and research institutions also use radionuclides in the Great Lakes basin. While these sources use only small quantities of radioactive materials, they are numerous and the total quantities may contribute significantly to the burden of radioactive materials in the environment.
The Task Force identified tritium, carbon-14, iodine-129, isotopes of plutonium and radium-226 as radionuclides that merit separate studies and further reporting because of their patterns of use and discharge; of their physical, chemical and biological properties; and of the special monitoring needs of lakes.
IJC is presently considering the inventory to determine what future directions should be taken.
Murray Clamen is secretary, IJC's Canadian Section and Joel Fisher is an environmental advisor, U.S. Section of the International Joint Commission. Both serve as members of the Nuclear Task Force. The full text of the Task Force's December 1997 report entitled "Inventory of Radionuclides for the Great Lakes" is available on the Internet in English with the overview and conclusions in French at http://www.ijc.org/rel/boards/nuclear/in vrep/index.html(.)
Revised: 7 April 1998
Maintained by Kevin McGunagle,
mcgunaglek@ijc.wincom.net