-16- samples from Wotho, Tarawa, Ponape, and Kapingamarangi, «40 contributed the major portion of the radioactivity. gamples collected at the same time Other contained wi61,185, radioisotopes identified with the 1958 fallout. Some samples, Buch as coconut crab abdomen and whole fish from Wotho, tained gn®>, whereas others, none, such as land plants, Some of the land plants con- contained contained measurable amounts of the long-lived fission products es?37 ana sr?°, The high- est level of sr?° was found in a sample of coconut crab cara- pace from Wotho isotope by the (18 ywuc/g dry). The concentration of this carapace of land crabs at Eniwetok has been Department of Energy Historian’s Office reported by Held (1957). ARCHIVES The relatively rapid decay of beta radioactivity in gome of the samples collected in 1956 at Tarawa, Wotho (Fig. 2 A-E) isotopes. Ponape and indicates the presence of short-lived A gamma spectrum analysis of one of the samples (leaves and stems of a Messerschmidia plant from Wotho) showed that gr? =Nb?” were the predominant radioisotopes in this sample. Thomas et al. (1958) found that these isotopes contributed approximately 84 per cent of the total radioactivity in a duplicate sample. The presence of short-lived isotopes in the 1956 samples indicated recent fallout at these islands.