Letter to James A. Joseph, Subject: Return of the Bikini People to Eneu Island

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Department of Energy Honorable James A. Joseph Under Secretary o f the Interior I am pleased t o reply t o your letter of April 12, 1979, regarding the possible return of the Bikini people t o Eneu Island. This response will address b o t h of the issues you raise: 1 . Your understanding o f previous statements by my staff. 2. More detailed information on estimated dose assessments f o r people living on Eneu Island, including various assumed living and eating patterns. With respect t o the first point, your understandings are, in general, correct. The more detailed information addressing the second point i s included as an enclosure to this letter. t o individuals, and 170 mremlyr and 5000 mrem/30 yrs t o a population) is t o be complied with, the people could return to Eneu only if it is assured t h a t adequate imported food would be available t o and used by the people for approximately 20 years, that food grown on Bikini Island i s not eaten for approximately 30 years, that residence is restricted tQ Eneu Island, and that visitation to Bikini Island is initially banned a n d subsequently controlled. Since the F R C guides were originally fqrmulated, an Environmental Impact Statement (EIS) was prepared for the resettlement of Enewetak Atoll. In the EIS, recommended criteria which are one-half of the FRC gui-dance f o r individuals a n d 80 percent of the 30-year FRC guidance for populations were proposed for evaluating land use options for use i.n planning the cleanup a n d rehahilitation of Enewetak Atoll. These

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criteria were recommended because of uncertainties in estimating future doses t o the people a t Enewetak Atoll. the return of people t o the Islands, direct radiation exposure measurements would be available and compared with the full FRC guidance of 500 mrem/yr t o individuals and 5000 mrem/30 yrs t o the population. These criteria for Enewetak were agreed t o by a17 parties t o the Statement, including the Environmental Protection Agency (EPA),who considered the Enewetak criteria or numerical values f o r the dose limits are only preliminary guidance and thata cost-benefit analysis must be undertaken t o determine whether the projected doses are really as low a s readily achievable and practical before proceeding with the relocation project. On the basis of such analysis i t may be prudent t o lower dose guidelines for this operation." We interpret EPA's comments a s essentially endorsing the Enewetak criteria, with the admonition that exposures be reduced even further clarification on this matter t o the Department o f Interior. We expect that the EPA will provide any needed The degree o f uncertainty in estimating doses on Eneu Island i s similar to that for Enewetak Atoll, Assuming, therefore, that Enewetak criteria are applicahle t o other situations in the northern Marshall Islands, the dose estimates for return of the Bikini people t o Eneu Island would be compared t o the Enewetak criteria as described above rather than to the FRC guidance. When this is done, itis found t h a t even with imported food the radiation doses t o the people on Eneu would not be expected t o be i n compliance with the Enewetak criteria Several combinations of residence and food constraints are discussed i n the enclosed, and are illustrated and summarized in the attachments t o the enclosed. Other considerations also are addressed. If any further refinement o f the data changes these estimates i n a significant way, we will immediately inform you. We trust that this is helpful t o you iR resolving the issue of the acceptability o f Eneu Island as a residence island. Assistant Secretary for Environment

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FOR RESETTLEMENT OF ENEU ISLAND Unless imported food is a substantial and continuing part of the diet of the Eneu population for about 20 years,unless the Eneu population can effectively be prevented from access to Bikini Island € or several years, and unless no food from Bikini Island is eaten for about 30 years,it is unlikely that radiation doses to people living on Eneu Island would bein compliance with federal radiation protection guidance1. Based upon previous experience and past practices, however, it is doubtful whether imported food will be apart of the daily diet and that access to Bikini Island can be restricted.Therefore,a return to Eneu Island should be delayed for close to 20 years if radiological dose is the only governing factor unless a firm commitment can b e made which will guarantee that adequate imported food will be available and used by the people, and that residence can be restricted to Eneu Island.Ifthe Enewetak radiation exposure criteria2 are to be applied to the Eneu population, it is unlikely that the radiation dos-es to the people would bein compliance with the criteria for approx i ~ atel y20 years, even if imported food is available and if mobility is restricted. Under either criteria,a return to Bikini Island would be delayed even longer because of the higher levels of radio nuclides in the soil. l The Federal Radiation Council (FRC) recommended exposure limits of and 5000 mrem/30 yrs to the average population of the U.S. 2Enewetak criteria are one half of the FRC exposure limit for individuals and 80 percent of the FRC 30-year exposure limit.

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I n August 1978the residents of Bikini Island left their Atoll because measurements of radio cesium made in April 1978 showed accumulations in the bodies of 13 out of 101people ; if this level were maintained for one year,it would result in an annual radiation dose equal to or greater than the 500 mremfyr federal radiation protection criteria for exposure of individuals. increased further had those people continued to live on Bikini Island. At that time the question was raised about whether or not the Bikini people could relocate on Eneu Island.Information then available on the radio nuclide content of test plantings of food crops on Eneu was inadequate, and there were insufficient samples of coconuts grown on Eneu Island to answer the question.In the Congressional Committee hearing2held on July25, 1978, i t was agreed that priority would b e give c to collecting and analyzing av zila ble data to update radiation exposure estimates for use by those who are considering whether the Bikini people should return to live on Eneu Island.In early 1979, new information was obtained so that dose predictions for residence on Eneu Island could,for the first time, b e based upon data from analysis of actual food items of the diet grown on the island rather than on theoretical predictions derived from soil concentrations. The dose rate might have People living on Eneu Island sources : 1) external irradiation receive radiation exposure from two from natural background radiation 31nter i or and Related Agencies Subcommittee, Committee on Appropriations, House of Representatives.

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(which is very low) and from radio nuclides remaining in the soil from nuclear tests at Bikini Atoll ; 2)internal irradiation from radio nuclides deposited in the body as a consequence of eating foods from the island area (including foods grown inthe contaminated soil and marine life from the lagoon) and from inhaling airborne radio nuclides. Because of the metabolic characteristics of the predominant radio nuclides (cesium-137 and strontium - 90)at Eneu, bone marrow doses are expected to be slightly greater than whole body doses, and will be the limiting exposure. The external radiation dose rate has been determined from data obtained during a recent aerial radiological survey. The external doses to whole body and bone marrow for Eneu residents were calculated using measurements of external radiation and estimates of time spent in various areas of the island(e.g.,village,island interior, on the The internal radiation doses were calculated from estimates of the amounts and kinds of food in the diet(with and without imported foods) and from measurements of the radio nuclide content of these foods and of drinking water (see Attachments 1, 2,3, and 4).Levels of radio - activity in food shown in these attachments were obtained from analysis of samples collected on Eneu Island,except for pandanus which was not yet available.Since pandanus would be a diet constituent,the contributed dose is calculated from uptake coefficients and soil concentrations of radio nuclides. The 30-year dose commitment i s calculated assuming only radioactive decay with no reduction from other possible mechanisms.

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It is expected that some individuals on Eneu Island will receive doses higher or lower than the predicted average dose. This may result from: 1) eating a larger or smaller quantity of food than that shown inthe assumed diet,2)eating more o r less of certain foods containing the highest radioactivity levels, and 3) eating foods grown from areas on the island having soil concentrations higher or lower than the average.In this regard it should be noted also that the former " ...Federal Radiation Council suggests the use of the arbitrary assumption that the majority of individuals do not vary from the average by a factor greater than three.It4 used in establishing and distinguishing between guidance for the maximum annual dose to the average individual within that population and guidance for the potentially highly exposed individual within that This factor of three is Radiation Protection Guides for the U.S. were approved by the President and are used by federal agencies in the irradiation protection activities. These guides specify the radiation dose that should not 4Report No. 1, Background Material for &he Development of Radiation Protection Standards,Staff Report of the Federal Radiation Council, 5The "maximum annual dose" refers to the dose in that year in which the exposure of the average individual is greatest,taking into account the buildup and the removal and decay of radio nuclides in the body. The majority of the highly exposed individuals within this population are assumed not to receive an annual exposure more than a factor of three

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b e exceeded without careful consideration of the reasons for doing soy6 and that every effort should be made t o encourage the maintenance of radiation doses as far below these guides as practicable. comply with these standards,certain conditions must be met.First, the basic FRC recommendation i s " ...that they early radiation exposure LO the whole body of individuals in the general population ...s hould not individuals may be difficult to monitor under some circumstances ; thus they suggested that the limit to individuals may bemet by the use of average limits to the pop u alt ion. Second, therefore,the FRC indicated that:"Under certain conditions, such as widespread radioactive contamination of the environment, the onLy data available may be related to average contamination or exposure levels. these circumstances,it is necessary to make assumptions concerning the relationship between average and maximum doses. The Federal Radiation Council suggests the use of the arbitrary assumption that The FRC recognized, however, that exposure of the majority of individuals do not vary from the average by a factor greater than three. whole-body exposure of average population groups. .. It is critical that Thus, w e recommend the use of 0.17 rem for yearly this guide be applied with reason and judgment. noted that the use of the average figure, as a substitute for $ evidence concerning the dose to individuals,is permissible only when stated that the guidance should not be exceeded unless "...a careful study indicates that the probable benefits will outweigh the potential

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there is a probability of appreciable homogeneity concerning the distribution of the dose within the population included in the consideration is sufficiently large,consideration must be given to Third, ”When the size of the population group under the contribution to the genetically significant population dose. The Federal Radiation Council...recommends the use of the Radiation Protection Guide of5remin 30 years ...f or limiting the average genetically significant exposure of the total U.S.population. The use of 0.17 rem per capita per year, as described (above) as a technique for assuring that the basic Guide for individual whole body dose is not exceeded,is likely in the immediate future to assure that the go nadal exposure Guide isnot exceeded.”g body dose is considered to be the equivalent of the genetically Because of the absence of radiation pro tec ii on guides specific for the Marshall Islands,criteria were developed from the basic Federal guidance for evaluating land use options for use in planning the cleanup and rehabilitation of Enewetak Atoll .I” These criteria are presented here since they were developed subsequent to the decision regarding the cleanup and rehabilitation of Bikini Atoll.It was lo cleanup,Rehabilitation,Resettlement of Enewetak Atoll - Marshall

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recognized that decisions on land use involve consideration of predicted radiation doses which have inherent uncertainties. To make allowance for this,radiation criteria were chosen that are 50% of the annual Federal guidance for individual whole body and bone marrow doses and 80% ofthe 30-year whole body dose for population exposures.Therefore,the Enewetak criteria limits the dose to the whole body orthe bone marrow of individuals to 250 mrem/yr and the dose to the average individual within the population to 4000 mrem/30 yr. (It should be noted that use of a percentage of the FRC values ' I... is notto be viewed as an attempt to establish new standards but is considered to be a necessary precaution in the application of current standards. The adoption of limits for Enewetak equal to one-half the FRC guide for individuals and 80 percent of the FRC guide for 30-year limits i s a result ' I... of the uncertainty concerning dose estimates which depend greatly on the foods people will choose toeat and the way they will choose to live. While dose estimates are to be compared to these percentages of the FRC guides,actual exposure levels monitored after the people return should be compared tothe 100 percent values of the CALCULATED DOSES LIVING I N ENEU The calculated doses14 shown below ate for two living patterns and for two assumed diets. The diets are based on the recent experience 14All dose estimates are rounded off and are based upon information contained i n "An Updated Radiological Dose Assessment of Eneu Island at Bikini Atoll, "