INTERNAL DEPOSITION OF RADIONUCLIDES and the analysis at + months represents only radiological decay. Thus, the results are not directly comparable to those obtained fromanimals which were returned alive, and in which biological turnoveras well as radiological 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 separated and analysed, equal amounts of activity were found in each fraction. However, the storage of these fish in formaldehyde for 3 months may have permitted the diffusion of the radioelements from bone to muscle to take place. Furtherstudies on freshfish will clarify this point. The contamination of the fish in the lagoon 81 may represent the distribution in humanbeings. The absolute amount of internal contamination in the Rongelap people was, however, only a 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 clam (Table 5.10). The rare earth group constituted 33 percent of the total beta activity. The balance of the activity was contributed chiefly by Zr®> (21 percent) and Ru (32 percent). About 50 percent of the material found in the viscera of the fish was of the rare earth group. Very small amounts of strontium and barium were found. Inthe tissues of the fish, strontium, barium and the rare earths contributed only about 10 percent of the total activity. was considerably greater than that of the land animals studied. As fish form a large staple item in the diet of the Marshallese, the high 5.43 At the end of a 214-month experimental period. the excretion by the chickens of both beta and gammaactivity per 24 hours was 5 percent of the value measuredat the start at 37 days post detonation (Fig. 5.1). Analysis of pig excreta indicated a similar decrease of activity with time. In a 6-week period, the gamma activity excreted per 24 hours decreased to about 2.5 percent. of the activity excreted at 44 days post detonation. chickens were prepared both at the USNRDL and at the Argonne National Laboratory (ANL) to determine the pattern of deposition of fission products. Contact printing on X-ray no-screen film was found to be the most satisfactory method of preparing the autoradiographs. The discussion and conclusions presented below summarize the findings reported by Norris (15). The autoradiographof a tibia from a chicken less than 10 percent of the gross beta activity foundinthe excreta of the pigs from Rongelap at the same time. This ratio of 10 was approximately the same ratio found between the activity of the food, water and soil samples of the two locations. Radiochemical Analysis of Tissues and aereta, Radiochemical analysis of pig tissues indicated that 62 percent of the skeletal beta activity was derived from Sr®, 7 percent from Ba™°, and 10 percent from the rare earth group at $2 days post detonation (Table 5.8). The radioisotopic composition of the urine at this time wassimilar to that of the skeleton. The distribution of activity in the body of the pig 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 trabecular bone. The tibia and femur of a baby chick, which died spontaneously 47 days post detonation, showed the heaviest concentration of radioactive material in the diaphysis (Fig. 5.3). The end regions of the bone, which were laid down after the animals were removed from the contaminated environment, were relatively lacking inactivity. The region of greatest activity was in the diaphysis, which appeared to be ab- level of contamination is important. The excreta of the pigs from Utirik contained S06 7139 Autoradiographs A numberof autoradiographs of the tibiae and femurs of 1 chick, 4 pigs, 1 rooster and 2 sacrificed at 45 days post detonation (Fig.5.2) indicated a relatively uniform distribution of