71 in adults and 22 nCi in children, about 6 and 11% respectively of the maximum permissible lifetime body-burdenlevels for the populationatlarge, i.e.. “0 the ICRP value.'®9 Analyses of bone samples from several autopsies during the past 20 years gave estimated 9°Sr body burdenssimilar to those obtained from urinalysis (see Figure 57). 137Cs body burdens also reached their peak in about 1965, at nearly 0.7 uCi (23% of the permissible level for the general population). The body burdensof 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-made radioactivity) were considerably reduced by 1974, and presents dataalso for Utirik and Bikini.* The coconut crab was banned from thediet on Rongelap becauseofits high level of radioactivity, but about 2 years ago the ban waslifted on the southern isiands ofthe atoll because the radioactivity had decreased sufficiently (see Table 40). B. *5Fe BODY BURDENS IN RONGELAPESE In 1971 blood samples from 62 Rongelap residents were analvzed** for 55Fe, and their body burdenswere estimated by the methodof Beasley et al.!70 55Fe was knownto be present in the Marshall Islands in fairly high levels as a result of the *Mr R.Fairchild at BNL calculated the bone marrow dose for the 1974 data. **The 55Fe analvses were carried out by T.M. Beaslev and E E. Held at the University of Washington Schoolof Fisheries. Seattle. Table 43 Average Body Burdens of ®5Fe in Rongelapese, 1971170 Males Females No. of Body burden, Age samples 16-20 21-31 32-42 43-53 54-64 8 + 5 2 6 0.31 0.33 0.52 0.58 0.53 >64 3 0.48 16-20 6 0.23 21-31 12 0.34 32-42 43-53 54-64 >64 5 7 2 2 pCi 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 “oo of the maximum permissible levels for non-occu- pationally exposed individuals estimated with the total body as the critical organ. The values are slightly higher in females than in males, andsignificantly higher in older persons. °5Fe emits photonsof very low energy, and, sinceit is incorporated into the hemoglobin ofthe red cells, it results in relatively little irradiation of nucleated cells. Some blood samples from the 1974 surveyare also being analyzed for 95Fe. C. PERSONNEL MONITORING AT BIKINI In 1946, before Operation Crossroads, theresi- dents 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 survevs were done on Bikini and iater on Eniwetok Atoll.1?71-174 In 1967 the principal isotopes contributing to the gammaradiation field on Bikini and Eneu Islands were 137Cs, 89Co, 125Sb, and !55Eu; slight amounts of Pu were also found. Considerable variation was seen in the contamination of individual islands comprisingtheatolls of Bikini and Eniwetoksince different tests had been conducted on various ones. The contamination of Rongelap and Utirik was more uniform, being duelargely to fallout from a single detonation, Bravo. In 1968 an ad hoc committee reviewed the survey 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 Eneu), and in 1971 several Bikini families moved back to Bikini Island itself, which now has about 30 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 gammaspectroscopy wascarried out on personnelliving on