a 7] in adults and 22 nCi in children, about 6 and 11% respectively of the maximum permissible lifetime body-burden levels for the population at large, i.e., iio the ICRP value.!®® Analyses of bone samples from several autopsies during the past 20 years gave estimated 9Sr body burdenssimilar to those obtained from urinalysis (see Figure 57). 137Cs body burdens also reached their peak in about 1965, at nearly 0.7 pCi (23% of the permissible level for the general population). The body burdens of the Utirik people were considerably below those of the Rongelapese. Table 42 showsthat the estimated bone marrow doses of Rongelap people from internal and external sources (both natural and man-maderadioactivity) were considerably reduced by 1974, and presents data also for Utirik and Bikini.* The coconut crab was banned from the diet on Rongelap because ofits high level of radioactivity, but about 2 years ago the ban waslifted on the southern islands of the atoll because the radioacnvity had decreased sufficiently (see Table 40). B. *5Fe BODY BURDENS IN RONGELAPESE In 1971 blood samples from 62 Rongelapresidents were analyzed** for 55Fe, and their body burdens were estimated by the method of Beasley et al.170 55Fe was knownto be present in the Marshall Islandsin fairly high levels as a result of the *Mr. R. Fairchild at BNL calculated the bone marrow dose for the 1974 data. **The Fe analyses were carried out by T.M. Beasley and E.E. Held at the University of Washington School of Fisheries, Seattle. Table 43 Average Body Burdens of 5Fe in Rongelapese, 197117 Males Females Age No. of samples 16-20 8 Body burden, pCi 0.31 21-31 32-42 43-53 54-64 >64 4 5 2 6 3 0.33 0.52 0.58 0.53 0.48 16-20 21-31 32-42 43-53 54-64 >64 6 12 5 7 2 2 0.23 0.34 0.33 0.66 0.57 0.66 local nuclear testing program andalso from world- wide fallout, and to be concentrated by marine life, particularly fish. The estimated body burdens for the Marshallese tested (Table 43) are higher than those found for Japanese bomb survivors and for others tested, but they are not more than Yoo of the maximum permissible levels for non-occuPationally exposed individuals estimated with the total body as the critical organ. The vatues are slightly higher in females than in males, andsignificantly higher in older persons. 55Fe emits photons of very low energy, and, sinceit is incorporated into the hemoglobin of the red cells, ic results in relatively little irradiation of nucleated cells. Some blood samples from the 1974 survey are also being analyzedfor °°Fe. C. PERSONNEL MONITORING AT BIKINI In 1946, before Operation Crossroads, theresidents were evacuated from Bikini. After stays at Rongerik and at Kwajalein which proved unsatisfactory, they were relocated on Kili Island in the southern Marshalls, which also proved unsatisfactory. The Eniwetok people were relocated at Ujelang Atoll, to the west, after their evacuation. After the 1958 moratorium on atmospheric nuclear testing, numerous radiological surveys were done on Bikini and later on Eniwetok Atoll.171-174 In 1967 the principal isotopes contributing to the gammaradiation field on Bikini and Eneu Islands were 137Cs, 89Co, 125Sb, and 155Eu; slight amounts of Pu were also found. Considerable variation was seen in the contaminationof individual islands comprising the atolls of Bikini and Eniwetoksince different tests had been conducted on various ones. The contamination of Rongelap and Utirik was more uniform, being due largely to fallout from a single detonation, Bravo. In 1968 an ad hoc committee reviewed thesurvey results for Bikini and decided that Eneu and Bikini Islands were safe for habitation, with cer- tain measures recommendedto reduce exposure (see Appendix 13). In 1969 about 30 people started work on Bikini Atoll (living on Enew), and in 1971 several Bikini families moved back to Bikini Island itself, which now has about 50 Bikini people plus a few administrators and construction workers. Annual monitoring of personnel has been carried out since 1969. In 1974 radiochemical analyses were done on urine (see Table 37 and Appendix 12) and other samples, whole-body gamma spectroscopy was carried out on personnel living on