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ROUTING AND TRANSMI. SUP ~ Name, office symbol, room number, File Note and Ratum For Clearance Per Conversation ~irculate For Your Information Sea Me mment investigate Signatura tion to De~t. of Interior that crabs from the northern islands at Rongelap Atoll not be eaten. We could discuss this at..mext meeting of Bair Advisory DO NOT use this form as a RECORD of approvals, concurrences,disposals, c{earancea, and similar atilons
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Safety & Environmental Protection Divkion (516) 3L: ~L-.:_) Division of Operational & U.S. Department of Energy During past visits by DOE contractors, the people of Rongelap have asked for an official opinion on the radiological impact of coconut crabs from the Northern islands of their atolls. The following is an analysis based on available data to We have recently processed the coconut crab collected during the April 1978 field trip. The gamma emitting radionuclides are listed in Table samples from Rongelap that were analytical results for 90Sr and 1. In addition, the analytical results for the coconut crabs collected in 1974 by V. A. Nelson,University of Washington, LRE, and in 1975 by BNL have been included for comparison. Table 2 summarizes the 90Sr concentrations in the coconut crab at Rongelap from 1955 to The 1974 and 1975 samples were divided into three sample types: exoskeleton, muscle and hepatopancreas. In the 1975 samples, the hepatopancreas was included with other parts of the crab once thought to be inedible. Current information c~ncerning the dietary habits of the Xarshallese indicates that the cocoz’~t CK* is qenerallv–considered to have two edible Portions: the muscle, consisting of muscle tissue in the claws and the carapace, and the hepatopancreas, contained in the abdomen or rear section of the coconut crab body. The 1978 samples were analyzed according to this revised dietary breakdown of the coconut crab. The shell and other non-edible parts of the crab were not analyzed. Several comparisons and general statements can be made from the data in Table 1. First, the $~abs from the Northern islands (Lomuilal and Aerik) contain 137CS concentra-6 to 15 times higher Sr concentrations and 4 to 6 times higher tions than Southern island (Arbar) crabs in 1978. Secondly, in the 1974, 1975, and 1978 data, the concentration of 90Sr appears to be evenly distributed throughout the edible portions of the crab, while the 137CS activity seems to concentrate in the crab meat by a factor of 2 to 1 over the hepatopancreas.
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1974, 1975 and 1978 Arbzz Island coconut crab muscle results show a net increase ‘OSr and a 30 percentdata for hepatopancreas indicates & 4 percent decline for decline for 137CS concentratims. We do not believe this is indicative of any trend but does illustrate khe statistical problem of having a limited number of samples. Finally, the 1978 90Sr and 137CS concentrations in the Lomuilal and Aerik crabs are factors of 3 and 1.6 higher than the 1975 Kabelle coconut crab analytical results. (Kabelle is in the Northeastern sector of the atoll.) The average edible portions of the 1978 Northern island coconut cr=b meat had a dry mass of 65 grams while the average dry mass of the hepatopancreas for the coconut crabs from the same island was 75 grams. This corresponds to an average total intake per crab of 4 nCi 90Sr and 11 nCi 137CS. Assuming a consumption rate of one coconut crab per &oek for one year, this corresponds to an activity uptake models for 137CS and 90Sr to predict whole body and bone doses at the end of one year of consumption this ingestion rate would result in a body burden of 0.2 uCi (0.03 rem) for f37Cs and a body burden of 0.04 uCi for ‘OSr. The 90Sr bone burden would result in a dose commitment to bone of 0.6 rem. The bone marrow dose would be -0.1 rem. The 90Sr bone marrow dose would be at 20 percent of the current suggested limit of 0.5 rem while the bone dose would be 20 percent of the current limit of 3 rem for the individual in the general public. The dose commitment due to the consumption of one Arbar coconut crab per week would be: 0.01 rem total body due to 137CS, 0.05 rem bone due to 90Sr and 0.01 rem bone marrow due to 90Sr. The external total body dose commitment as estimated in BNL 50797 for the adult male living on Rongelap is 275 mRem/yr. When the ‘OSr dose commitment to bone marrow from eating crabs from the Northern islands is added to the total body burden, the resultant annual dose would be -80 percent of the current standards. Consequently, we feel that the Rongelapese should not eat coconut crabs from the Northern islands. Coconut crabs collected from the Southern part of the atoll may be–consumed without contributing significantly to the dose commitment of the Rongelap If you have any questions concerning these data or if we can be of further
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Mean Concentration of 90Sr in Coconut Crabs Collected at Rongelap Atoll from 1957 - 1974 Sample Collection Collection Number of in pCi/g, dry Type Area Date Samples 9osr oconut Crab, Muscle Rongelap I 1957-58 12 14 oconut Crab, Exoskeleton Arbar I 1959 2 480 .. These data were taken from the,following sources: Collection Date Source 1958-1971 LRE, unpublished data ,. 27 pCi/g, wet, multiplied bv a wetldrv ratio of 4.5. :. This table is a partial reprint of Table 7, NVO-269-32, “Radiological Survey of ?lants, Anir+als and Soil at Christmas Island and Seven Atolls ifithe
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