69 induced activities (59Fe, 57:58.60Co, 54Mn, 144Cs- 144Pp, 957.95Nb, and !°6Ry-106Rh), Radiological assessment has included surveys for gammaradiation levels on the islands; radiochemical studies of soil profiles, lagoon bottoms, marinelife, plants, animallife (¢.g., rats, coconut crabs), food items, and urine samples; and gamma spectrographicanalysis of internally deposited gammaemitters in personnel. The medical team has been responsible since 1969 for monitoring the body burdens ofthe people returning to Bikini, as well as ofthe Marshallese ex- posed to fallout and their controls, and morerecently also of the people returning to Eniwetok. The 1974 studies of environmental radiation on Rongelap, Utirik, and Bikini are being published separately. 165 Until 1965 gammaspectroscopy was done ina 21-ton steel chamber built at BNL for shielding, with additional housing for the counting equip- ment (Figure 53). The subject to be counted took a soap and water shower, put on paper pajamas, and then stayed in the chamberfor about 15 min, during which soft music was piped in. Only a few small children were apprehensive during the procedure. More recently whole-body counting has been done with a smaller “shadow-shield” arrangementof lead bricks, a modification of the radaga | E ——— Rongelap male 3,000 [- —+-- BNL medicai team 4 male | 1,000 -E 500 E - F 100 E \ \ marized in Tables 37 to 40; the results of indi- vidual urinalyses are given in Appendix 12.* By 1974 the only detectable gamma emitter was 137Cs; its levels are given for Rongelap, Utirik, and Bikini individuals in Appendix 12 and for groups in Table 41. Since the return to Rongelap, no differences have been seen between exposed and unexposed groups. Figures 56 and 57 show the estimated body burdens of gammaemitters and 9Sr for the Rongelap people at various times after the initial exposure in 1954. After their return to Rongelap the body burdens increased. ®5Zn was present for a few years, apparently from fish in the diet; the rea- son for its rapid decrease was not immediately ap- parent but may be related to movements of marine life in and out of the lagoon. Small amounts of 6Co were identified in personnel during the early years after the return (the highest concentration was in clams). 9°Sr body burdens reached their highest level during 1962 to 1965 at about 12 nCi “Weare indebted to Mr. Edward P. Hardy, Jr., Director, En- vironmental Studies Division, AEC Health and Safety Laboratory, New York, N.Y., for carrying out the radiochemical analyses. ~ “. A N i \ Radionuclides in Coconut Crabs From Rongelap Year 1964 ‘A } y 0.4 Table 40 7 | 0.8 Energy (MeV) 1.20 137Cs, pCi/kg 1.60 1965 1969 1972 1973 1974 90Sr, pCi/g Ca 1,140 1962 Figure 35. Gammaspectra obtained by whole-body counting, males, 1974 (——, Rongelap; -~-, BNL medical team). SO0b 1 bb water, and crabsover the past 5 years are sum- 1961 OK A 50 10 0 radiochemical analysis. The results of radiochemical analyses ofurine, 3 4 Activity (counts/15 min) 10,000 the low levels present in the people (see Figure 35).167.168 Annual collections of 24-hr urine samples from a numberof people have been madefor 4 J uw md “4 Hanford model!96 (Figure 54). In 1974 spectro- graphs showed a characteristic peak for !37Cs and 65Zn, but 8°Co was barely discernible, if at all. at 1,224 (1,317; 1,086; 50,281 (39,292; 45,318; 66,234) 12,700 7,775 (8,540; 7,010) 5,900 (5,600; 6,100: 12,900* 6,800; 5,100) 37,065 (64,700; 9,430)* 6,600 (5,000; 8,200) 4,800* 1,113; 1,378) 758 (865; 628; 780) 724 705 (910; 500) 353 (376; 419; 359; _ 933* . 259) 3,950 (6,639; 1,267)* 448 (290; 606) 290* “From northern islands of Rongelap Atoll, where radiation dose was much higher.