-15- noted: w281,185 contributed the major portion of the radio- activity in Scaevola leaves from Kusaie and in Messerachmidia and Scaevola leaves from Ujelang zn (Lowman t al. 1959), and — 65 was predominant in fish tissues from Ponape and Utirik. Co?’ was present usually in lesser amounts, and co?8 ana C099 were found only in a sample of clam kidney from Ujelang and a fish liver sample from Utirik. Other radioisotopes were present only in a few samples. cs137, in plants for example, was found from Kapingamarangi and Utirik, a few samples from Kusaie, cel41, 144_p,144 in Ponape and Ujelang, and mn>4 in fish skin and gut from Ponape and clam kidney from Ujelang. Pe? was detected once only, in a sample of skipjack muscle from Ponape. The quantitative results of the gamma spectrum analyses shown in Table 3 are based on analyses made approximately eighteen months after the samples were collected; consequently the shorter-lived radioisotopes Zr95-nb?° Co?8 (71 days) Rut93_pp103 (40 days) (half life 65 days), and cel4i (32 days) had decayed to insignificant or non-detectable levels. Ina 16l- DOF,ARCHIVES gram sample of yellow-fin tuna from Ponape, however, Zr’”-Nb were found in low amounts (0.12 pyc/g at time of counting); at time of collection the level of z2r95-nb95 would have been 40 pyc/g. K49 was present in all samples analyzed. In some /¢