* 4.2 ' . RESULTS AND DISCUSSION Significant amounts of beta and gamma activity were found in the tissues of the 65 fish and marine invertebrates collected (Tables 4.1, 4.2, and 4.3). The distribution of radioactivity in the tissues of the large fish (>150 g) collected in the Rongelap and Rongerik lagoons (Table 4.2) indicated that approximately 40 per cent of the activity was found in the skeleton. Muscle contained approximately 15 per cent of the total internal activity and the viscera contained approximately 20 per cent. One exception was a parrot fish from Eniwetak which had an unusually high activity in the viscera, probably associated with recent ingestion of a highly contaminated food source. The remainder of the activity was found on the skin and gills. The beta-to-gamma ratio was approximately 1:4 in most of the tissues analyzed. Physical and chemical analysis of one fish indicated that this high gamma-to-beta ratio was largely accounted for by the induced activity of Zn® and Fe hal i K-capture emitters. Further work on fish is in progress to see if this situation is a unique or generalized finding. The total activity found in the ternscollected on the various atolls (Table 4.4) was less by a factor of ten or more,than that of the corres- ponding fish populations. The activity of the terns collected from the Rongelap Atoll was higher than that of the terns from Rongerik Atoll and considerably higher than the terns from the Bikar Atoll. wee The radioanalysis of a rooster from Rongelap Istand (Table 4.4) indicated relativeiy high beta and gamma activity (0.7 pc/ whole animal). The ratio of beta activity to gamma activity was approximately one. The rooster roamed freely on the island and derived his activity from continuous ingestion of contaminated water and foodstuffs which had incorporated fission products. in comparison, chickens collected at one month post-detonation and removed from the contaminated area continued to show internally deposited activity in detectable amounts fora period of only about 6 months. In the rooster over 90 per cent of the total activity was found in the skeleton, 3.5 per cent in the muscle, and 2.3 per cent in the viscera. Only very smal! amounts of activity were found on the skin and feathers and even less in the lungs. Considerable variation exists in the concentration of activity per weight of individual tissues as a function of the geographic location of the animals. Inthe Rongelap Atoll, for example, fish and invertebrates caught in the northern part of the Jagoon contained, on the average, 3 to 4 times the amount of internally deposited fission products as that found in fish from the southern lagoon. This is consistent with the fact that the northern lagoon was exposed to higher concentrations of fall-out material. eh, ' are -17- 310 26