a ae” fhe det 2 REEL ced Fe iy tay + The or -2 4 Set Yt te. 7 oh ine wo shan et ft . CHAPTERIll i ThE _ the ra Sal ies, ee, we ak ont boat hg es 2 . ree fs iis, Sarit +i ¥, atPeeee th SRE t RE, , : wet ene eat a Radiochemical Analyses Tables 24 and 25 show the radiochemical analyses made by AFL for the 1954-55 surveys,? and Tables 26 and 27 for the July 1956 survey.’ In two pools of 15 and 19 fish muscle samples collected in late July 1956 and analyzed by AFL no radiostrontium was found. Tables 28 and 29 show the radiochemical apelyses made by NRDLfor the February 1955 survey,’ and Tables 30, 31, 32, and 33 for the February 1956 survey.‘ Table 34 shows additional analysis of soils from the February 1956 survey including data on exchangeable calcium. Tables 4, 5, 6, 13, 14, 19, 20, 23, and 35 show analyses by HASL. In terms of a potential biological hazard the strontium—90 activity 1s of most interest. At one year post detonation NRDL reports: - In muscle and viscera samples of the animals from Rongelap, Utink, and Rongerik, Sr® contributes approximately 0.5 percent of the total beta activity. Sr® is present in an approximately 1:1 ratio with Sr”. Since the Hunter and Ballou calculations indicate that Sr” and Sr” each contribute about 2 percent of the total beta activity at one year after fission, there does not appear to be any fractionation of radiostrontium into the soft tissues. As expected, most of the internally deposited radioactivity was found in the skeleton. “Tissues of a few marine specimen were analyzed for Cs'*’ (37-year half-life)* since this nuclide was present in high concentrations in water and coconut milk from this area. The tissues of the rooster and of the coconut crab contain significant amounts of Cs’. A very high fraction of Cs’ activity was noted in the “Newest estimates Indicate 27.7-year half-life. muscle of the rooster (40 percent of the total beta).*. Further radioanalyses of marine specimens indicated that the rare earth group con- stituted a few percent of the total beta activity. Ru'*-Rh™ and Zr®-Nb® contributed the largest percentage of the total beta activity.” The AFL reports: . The Sr values for food plants, except coconuts, collected in October 1955 approximate the theoretical proportion of mixed fission products activity” at 1.7 years, 4 percent. Coconuts contained 0.1 percent Sr® with appropriate correction for time of collection. . . . “.. . In contrast to the strictly marine forms, the coconut crab, which feeds principally on land plants, had Sr® levels of 3 percent in the muscle and 12 percent in the hepatopancreas or liver, where calcium salts are stored. The radioisotopes in salts leached from the carapace were found to consist entirely of Sreyh . . Radionuclides of Sr, Cs, Ce and their daughters did not accountfor the total activity in most (fish) samples analyzed. Complete fission product analyses of samples collected at Eniwetok and Bikini Atolls indicate that non-fission-product radionuclides may account for more than half of the total activity in some fish. Zn® contributes one-fourth or more of the total activity in shark muscle as determined by radiochemical analysis and confirmed by following the decay.”’ (Zn® is not a fission product.) The two-year survey by NRDL continues to indicate the high percentage of Zn® in fish. SectionIV. 23