The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences.

The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Robert M. White is the president of the National Academy of Engineering.

The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an advisor to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Kenneth I. Shine is president of the Institute.

The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. Robert M. White are chairman and vice chairman, respectively, of the National Research Council.

The Committee on Radiological Safety in the Marshall Islands was established by the National Research Council in response to a request from the U.S. Department of Energy (DOE) to assist the department in evaluating the radiological safety of the Marshall Islands, particularly Rongelap Atoll. The need for such an evaluation stems from questions over the possibility of meeting the radiological provisions of the memorandum of understanding (MOU) between the Republic of the Marshall Islands and the United States regarding the resettlement of Rongelap Atoll. The issue of resettlement itself originated in the desire of the Marshallese to return to the atolls from which they were evacuated as a consequence of nuclear-weapons testing by the United States during the 1940s and 1950s. The National Research Council was asked to review the scientific studies undertaken by DOE¹ to determine the potential radiological hazard, if any, to persons who might return to live on Rongelap Atoll.

A crucial provision of the MOU is that resettlement will occur only if no person returning to Rongelap and subsisting on a native-foods-only diet will receive a calculated annual whole-body radiation dose equivalent of more than 100 mrem above background. The scope of radiological studies needed to assure compliance with this MOU can be focused somewhat in the present context because of the radioactive decay and normal weathering processes that has taken place in the 40 years since the BRAVO detonation. At the present time, the only isotopes that contribute significantly to the dose on Rongelap are those of strontium-90, cesium-137, plutonium-239, plutonium-240, and americium-241. Of these, cesium-137 accounts for more than 90% of the estimated dose, strontium-90 is the second most significant contribution at 2-5%, and the transuranic nuclides contribute less that 5% to the total estimated dose (Kercher and Robison, 1993). This narrows considerably the effort to investigate and model the potential doses received from fallout radionuclides by those who might choose to resettle on Rongelap.

Another provision of the MOU that is of importance to the people of Rongelap as they consider resettlement is an action limit of 17 pCi/g for concentrations of plutonium in the island's soils. This action level in the MOU was based on a U. S. Environmental Protection Agency (EPA) action value of 0.2 µCi/m² for protection of the public from radionuclides in the environment. The EPA action level was developed for application to recent contamination, thus all of the radioactivity was considered to be concentrated within the top 1 cm of the soil. The MOU action limit of 17 pCi/g was derived by DOE from this 0.2 µCi/cm² EPA guideline

using a soil density of 1.2 g/cm³ appropriate to Rongelap and assuming that the radioactivity was in the top 1 cm of soil. Because the contamination on Rongelap took place nearly 40 years ago the MOU considers the potential for subsequent radionuclide migration in the soil by providing provisions for averaging of the 17 pCi/g radionuclide concentration over the top 5 cm of soil.

In this report, the committee restricts its attention largely to the technical aspects of the issues surrounding resettlement of Rongelap Atoll. The committee recognizes, however, that major, and equally important, social, ethnological, and political elements will also influence resettlement decisions by the Rongelap people. It has, therefore, during its deliberations, tried to maintain due consideration of factors—such as physical, biological, logistical, cultural, and psychological factors—that may reasonably apply to or might come to bear on the resettlement of the Rongelap people and their continued well-being.

It is the desire of all parties that resettlement occur in a timely fashion but without sacrificing the ability of the Rongelap people to pursue their lives without an unacceptable risk from radiation. The proposed resettlement program is bilateral. Its success will depend on mutuality of purpose and intent. Integral to the program must be a commitment to information-sharing and to direct, unambiguous communication. The committee assumes DOE will ensure that all relevant information and documents in its possession are made available to the Rongelap people on request and that all recommendations by the present National Research Council committee will be forwarded to the Republic of the Marshall Islands and to the Rongelap Resettlement Project Scientific Peer Review Group.

Because of the many references made in this report to the provisions of the MOU between the United States and the Republic of the Marshall Islands, the full text of the MOU is provided as an appendix. It should be noted, however, that the committee was not asked to review or comment on the provisions of the MOU, as these are the result of international negotiations, and will do so only as it effects the scientific studies needed to provide assurances that its provisions can be met.

DOE requested the assistance of a National Research Council committee to help it decide whether "good science" was being used in determining the appropriateness of resettlement of Marshall Islands atolls that were affected by the atmospheric fallout from nuclear weapons tested in the region in 1946-1958. The National Research Council appointed a group of eminent scientists to review and provide recommendations on radiological-health issues in the Marshall Islands. This group was to review and comment on the scientific and technical merit of the processes and procedures used by the DOE to evaluate the resettlement potential of Marshall Islands atolls affected by fallout and by actual detonations. The committee, established in the Board on Radiation Effects Research of the National Research Council, was asked to provide advice on the scientific validity of the technical studies, including comment on the methodologies of investigations of various kinds: determination of body burdens by bioassay, dose modeling for estimating ingestion and inhalation of radioactive materials, modeling and confirmatory assays of the soil-to-food pathway, remedial measures to reduce plant uptake of radioactive materials, and the application of current international standards for

radiation dose limits in this particular environment. Particular emphasis was to be placed on the evaluation of procedures for environmental monitoring and dose assessment necessary to determine the doses to people who wished to return and to live in these atoll areas and to consume local-only foods from portions of Rongelap Atoll and surrounding atolls that can support a return to their native habits and ways of life. The committee was asked to review the DOE programs and accomplishments, compare them with current practices, and suggest where additional data might be required for prudent decision-making as to potential resettlement. The committee includes not only radiation scientists, but experts in anthropology, ecology, genetics, medicine, nutrition, psychology, and statistics.

Specifically, the committee was asked to carry out the following activities:

• Review and comment on the applicability of current International Commission on Radiological Protection (ICRP) recommendations on annual dose limits for general populations as they pertain to anticipated dose commitments after resettlement in potentially contaminated areas of the Marshall Islands.

• Evaluate and comment on the adequacy of followup analytical techniques such as whole-body counting techniques and urine assay, to measure the accumulation and elimination of internally deposited radioactive materials in people after resettlement in potentially contaminated areas.

• Review and evaluate methods to reduce the ingestion and inhalation of radioactive materials by inhabitants of the Marshall Islands, particularly persons that resettle Rongelap Island and other islands in the Rongelap Atoll.

• Evaluate the radiological implications of proposed dietary regimens for persons who resettle Rongelap Atoll, taking into account both native and imported foodstuffs and the range of variation in diet among individuals, including persons of different age groups and both sexes.

• Advise on the long-term health consequences of various remedial actions directed at the physical environment that might be proposed to improve the habitability of islands in the Rongelap Atoll.

• Evaluate metabolic and dosimetry models for ingested radioactive materials to determine which are the most valid for application to inhabitants of the Marshall Islands.

To make those assessments, the committee was asked to review recent ICRP reports, technical documents, and other data relevant to the environmental assessment of Rongelap Atoll and, to the extent necessary, draw on reports of experience in other Marshall Islands areas. The committee was also asked to review the scientific literature on bioassay methods and, by interview or other means, gather the views of scientists and other persons familiar with the needs of the Marshallese. The overall aim of the committee's activities was to review and

evaluate the procedures that DOE scientists use in technical assessments concerning the potential resettlement of islands in the Rongelap Atoll and, as required, other Marshall Island atolls affected by the atmospheric nuclear-weapons tests.

In meeting its charge, the committee had access to reports (both internal and published) prepared by DOE contractor staff that covered the wide range and varied aspects of the radiological assessments being conducted in the Republic of the Marshall Islands (RMI). In addition, the committee members visited DOE contractor laboratories to observe the procedures and facilities developed and applied in their radiological studies, conducted numerous discussions with DOE contractor staff and with other scientists actively engaged in the investigation of conditions in the Marshall Islands. Finally, committee members visited the Marshall Islands to better connect the written reports with first-hand insights from a close look at the sites of current radiological studies on Bikini and Rongelap and to observe the conditions on the islands of Mejatto and Ebeye, where many of the previous residents of Rongelap now reside. Discussions were conducted both at the National Academy of Sciences facilities in Washington, D.C., and on Mejatto with the leaders of the people of Rongelap who wish to resettle. The committee also was provided with detailed information on the studies being conducted by the Nationwide Radiological Study of the RMI and the Rongelap Resettlement Project, both directed by Dr. S. L. Simon. Dr. Simon is a radiation scientist who has been employed by the Republic of the Marshall Islands to lead these projects.

This report is organized to reflect study of the characteristics of the land and people, elements of environmental and dose modeling, characteristics of potential remediation activities, the applicability of dose limits, and recommendations for post-resettlement monitoring. Chapter 1 is an introductory discussion of the environmental and cultural factors that underlie the desires of the people of Rongelap to resettle their island homes; it also provides a general discussion of the sources and measurements of radiation up to the present time. Chapters 2-6 evaluate the technical activities that have been undertaken to assess the radiological conditions on Rongelap. Chapter 7 addresses the applicability of dose limits in discussions of resettlement. Chapter 8 considers the applicability of possible remedial actions as they might apply to Rongelap. Chapter 9 considers the applicability of current technology to support the post-resettlement environmental and biological monitoring required to meet the conditions specified in the MOU that was signed by representatives of the people of Rongelap, the Republic of the Marshall Islands, DOE, and the U.S. Department of the Interior.

The committee's work was greatly facilitated by a number of people and organizations. Within the U.S., we are primarily grateful to Dr. William Robison of the Lawrence Livermore National Laboratory and Drs. L. C. Sun, A. Moorthy, E. Kaplan, and C. B. Meinhold of the Brookhaven National Laboratory. On the Marshall Islands trip, Dr. Keith Baverstock and Dr. Steven Simon, Director Nationwide Radiological Study, Republic of the Marshall Islands, were instrumental to the committee's scientific activities, and Mr. Kent Hiner of Raytheon to its physical needs; Dr. Robison provided an excellent description of his environmental studies underway on Bikini; and Mr. Randy Thomas, who accompanied our group as a representative of the Rongelap community, was instrumental in describing the importance of the islands to their way of life. The committee also benefited from numerous discussion with representatives of the Marshall Islands, both during their visits to the U.S. and in the Marshall Islands, including Mr. Peter Oliver, Under Secretary, Minister of Foreign Affairs, Republic of the Marshall Islands; Senator Johnsay Riklon, Rongelap/Utirik Atoll Local Government Council; Mayor Billiet Edmond, Rongelap Atoll Local Government Council; and others. The necessary contacts with, and briefings by, the Department of Energy were ably handled by Mr. Thomas Bell and Dr. Harry Pettengill. Dr. Douglas Grahn, liaison with the Board on Radiation Effects Research, contributed materially to our activities. Finally, in the persons of Drs. Dennis Mahlum, Larry Toburen, Evan Douple, and Ms. Doris Taylor, the committee enjoyed excellent staff support.

Radiological Assessments for Resettlement of Rongelap in the Republic of the Marshall Islands