EO ee ee er INTERNAL DEPOSITION and the analysis at 4 months represents only radiological decay. Thus, the results are not directly comparable to those obtained from animals which were veturned alive, and jn which biological turnover as well as rachological decay were operating. The largest fraction of the gross beta activity in the fish was contributed by the concentration of radioactive material in the viscera. In two of the fish in which bones and muscle were sep- arated and analysed, equal amounts of activity were found in ench fraction. WTowever, the storage of these fish in formaldehyde for 3 months may have permitted the diffusion of the radioelements fron: bone to muscle to take place. Further studies on fresh fish will clarify OF RADIONUCLIDES may represent the distribution in luman beings. The absolute amount of internal contamination in the Roneelap people was, however, only 2 tenth of that found in the animals. At 4 months post detonation, the alkaline earths comprised less than 2 percent of the total activity in the chum (Table 5.10). beta activity. The balance of the activity was contributed chiefly by Zr"* (21 percent) and Rus (32 percent). About 40 percent of the material found in the viscera of the fish wits of the rare earth ereup. Very small amounts of strontium and barium were found. In the tissues of the fish, strontium, barium and the rare earths contributed only abont 10 percent of the total activity. was considerably greater than that of the Jand anunals studied. As fish form a Jaree staple 5.43 item in the diet of the Marshallese. the high level of contamination 3s important. At the end of a 214-month experimental period, the excretion by the chickens of both beta and gamma activity per 24 honrs was 5 percent of the value measured at the start at 87 days post detonation (Fig. 5.1). Analysis of pig excreta indicated a decrease of activity with time. In a period, the gamma activity excreted hours decrensed to about 2.4 percent of similar G-week per 24 the ac- tivity excreted at 44 days post detonntion. The excreta of the pigs from Utirik contained Jess than 10 percent of the gross bet activity found in the excreta of the pigs from Rongelap at the same time. This ratio of 10 was approx- imately the same ratio found between the activity of the food, water and soil samples of the two locations. Radiochemical Analysts of Tissues and Ex- ereta, Raciochemical analysis of pie tissues licheated that 62 percent of the skeletal beta activity was derived from Se". 7 percent from Bat? and 10 percent from the rare earth sroup at 8&2 days post detonation (Table 5). The radioisotopic composition of the urine at this time was similar to that of the skeleton. ‘The distribution of activity an the body of the pig 9002159 The rare earth group constituted 33 percent of the total this point. The contamination of the fish in the lagoon $1 Autoradiographs A aummber of autoradiographs of the tibiae and femurs of 1 chick, 4 pigs. 1 rvoster and 2 chickens were prepared both at the LSNRDLI and at the Argonne National Laboratory (ANIL) to determine the pattern of deposition of fission products. Contact printing on A-ray no-serees filam was found to be the most satisfactory method of preparing the antoradiowyaphs. The discussion and conclusions pre- sented below summurize.the findings reported by Norris (14). The antoradiograph of a tibia from a chicken sacrificed at 45 days post detonation (Fig. 5.2) indicated a relatively uniform distribution of the activity throughout most of the bone, with the highest concentration of activity in the area adjacent to the epiphysis. This area of high activity corresponds to an area of dense trabe- cular bone. ) The tibia and femur of a baby chick, which died spontaneously 47 days post detonation, showed the heaviest concentration of radioactive riaterial in the diaphysis (Fig. 5.3). The end recions of the bone, which were laid down after the antmals were removed from the contaiminated environment, were relatively lacking inactivity. The reeion of rreatest activity was li the diaphysis, which appeared to be ab-