-31rations on two dif9] MEV peaks were observed in cobalt sepa ferent 1956 samples. Fish liver homogenate collected at Belle sample Island, Eniwetok, September 22, 1956, and a plankton (No. 42) taken 470 miles west of Eniwetok, September 13, 1956, Y (Seymour et al.,1957) both exhibited strong .61 MEV peaks tn the whole samples as well as in the cobalt separation. The peaks attributed to Co?! and Co°° were also present in the whdle samples and in the cobalt separations. Raditochemical separations for zinc were made on two (2) fish liver samples: a. 4 Fish liver homogenate, Belle Island, Eniwetok Atoll, September 22, 1956. ‘RR a “zz ae b. Bonito liver, How Island, Bikini Atoll, September 22, 1956. A comparison of the c/m PB for the total sample and the a eekly zn? fraction could not be made for sample I because the total Sample count was made with the methane gas-flow counter and the zn°> count with the end window geiger tube. However, sample II and its ze? fraction were counted on the methane gas-flow counters and out of a count of 8,450 c/n PB c/n B in the whole sample, 3,600 were obtained in the zinc separation. The 7Y curves for the two samples and that of a zn°? spike are shown in Fig. 9. A small amount of contamination by cobalt radioisotopes was present in the zine separations. Supplementary evidence concerning the distribution of the non-fission products to that obtained by chemical and ion exchange