-13- Kapingamarangi, Tarawa, Ponape, and Kusaie was only slightly above the background level of the counter. The naturally- eccurring isotope «40 contributed most of the radioactivity, which, for the samples listed in Table 3, ranged from 1.8 to 19 upc/g of wet tissue. The levels of radioactivity in samples from one of the islands at the test site (Bikini) were considerably higher than in the "off-site" samples. For example, at Bikini Island in September 1956, algae collected two months after comple- tion of the Redwing series, averaged 5,500 wuic/g, whereas samples collected at the same time at Ponape Island averaged 78 wuic/g. Similar comparisons with the fish, coconut and sea cucumber tissues showed that the major portion of the radioactivity was deposited at or close to the test sites at Eniwetok and Bikini Atolls. Comparisons of the radioactivity of different tissues and of similar tissues at different times are limited by the number of samples. made. However, some general conclusions can be The algae and fish liver contained the highest levels of radioactivity and the coconut meat and milk were the leas Department 0 Energy radioactive tissues at the majority of the stations. Histo s The samples collected in January-February, 1955, at the atolls east of the test site contained relatively high amounts