Letter to T F Mccraw, Subject: Personal Monitoring Services to the Residents of Rongelap and Utirik

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BROOKHAWN NATIONAL LABORATORY Divkion of Operational and U.S. Department of Energy We have recently returned from our most recent field trip to the Marshall Islands. Our objectives were to provide personal monitoring services to the residents of Rongelap and Utirik, collect site specific environment samples at these two atolls and repair the windmills so that the air sampling program could be reinstated. All of these objectives were completed during the August 16 - September 7 field trip. At Rmgelap, a new generator was installed and began to slowly charge the batteries that power the air sampler. Because the batteries were discharged and the trade winds had not commenced, we anticipate that it will take several months to store enough energy in the batteries so that a constant air sample can be taken. The first air sample may be available next January. Also we established three permanent sampling locations for coconut, breadfruit, and pandanus. This will allow us to monitor yearly variations between soil and vegetation activity concentrations. Finally, sixty-seven persons participated in the whole body counting program and sixty-three persons contributed urine samples. Table 1 summarized whole body counting results in each age and sex category and compares the wean 1979 137CS body burdens with the mean 137CS body burdens measured by Stan Cohn in 1974 and 1977. Appendix A lists cumulative results for all gamma emitting nuclides detected from 1974 to 1979. The data in Table 1 suggests that the 137Cs body burdens are continuing to decrease. When comparing the individual data in Appendix A with prior results, one observes that not everyone’s 137cs body burden declined. Of the twenty-five persons with prior whole body counting histories twenty-one body burdens declined, three increased and one remained unchanged. The increase may be due to a change in diet or to a short residence interval prior to the In the August 3 letter to Bill Stanley, we stated tht the minimum sample size required to obtain the true value for the population mean 137body burden at the 90% confidence limit was thirteen. As Table 1 indicates, we did not

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count the minimum sample size required for every sex and age category. This was due to a lack of adolescents on the island. According to the magistrate, we whole body counted all adolescent males and females who were currently living on Rongelap Atoll. At Utirik, there were sufficient persons present on the atoll to obtain the desired sample size. Occasionally more than thirteen persons from a given age or sex category were whole body counted. In total, eighty-three individuals participated !in.the bioassay program and eighty-eight were whole body counted. The population means, standard deviations, and ranges, along with the previous results as reported by S. Cohn in 1974 and 1977 for each sex and age category are listed in Table 2. From these data, it is clear that the 137CS mean body burdens have continued to decline. Appendix B lists the current individual body burden results along with those which have been reported over the ~ast We also selected standard environmental monitoring stations. As at Rongelap, these specific locations will permit us to observe the yearly variations between the soil-vegetation activity concentrations. Finally, the windmill was extended ten feet. This should place the blades sufficiently above the coconut trees to avoid the damping of air currents which prevented this unit from supplying power for our air sampling equipment. As at Rongelap, the condition of the batteries and the lack of steady airflow from the trade winds means that January may offer the first three-month air sample. At this time, urine samples have yet to bereceived from Kwajalein. Dose equivalent commitments and body burdens from 90Sr will be computed as soon as the samples are received and processed.

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1974 - 1979 Summary of 137Cs Mean Population Body Burdens - Rongelap Atoll Adol. Adol. Male Fema16 Adult Male Adult Female Male Female Child Child

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1974 - 1979 Summary of 137Cs Mean Population Body Burdens - Utirik Atoll Adol. Adol. Male Femal, Adult Male Adult Female Male Female Child Child

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., 1974 - 1979 Whole Body Count Results - Rongelap Adult Males *Data obtained from individual who is currently living on Ebeye. Data not used to compute mean, standard deviation or range of Rongelap population Cs body burden.

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1974 - 1979 Whole Body Count Results - Rongelap Adult Females *Data Obtained from individual who is mean, standard deviation or range of currently living on Ebeye. Data not used to compute