Cohn, Robertson, Conard The presence of Co“? in the soft tissue of clams was noted for the first time in the 2-vear resurvey (Weiss and Shipman, 19571. The Coaccounted for the major fraction of the total activity in the clams. The very marked ability of clams to concentrate Cot selectively was verified in laboratory experiments (Gong et al. 1957) Land Animals Internal radioactive contamination of animals from Rongelap was determained by radiochemical analyses of the tissucs of domestic animals {pigs and chickens) sacrificed at various times following contamination (Cohn et al, 1955,. The internal contamination resulted from both inhalation and ingestion of contaminated food, with the latter being the more important route of entry. The bedy burden of fission products was ‘roughly proportional to the ganima dose rate on each island. The internally deposited activity in the pigs ving on Rongelap for } monthafter the detonation was tenfold higher than that of the human beings who were evacuated within 45 hours. The difference thus refiects the proionged stay of the ammuals m the contaminated area. Only a small percentage of the fission products initially present in the environment was readily absorbed from the Jungs and G. 1. tract and retained in the body of land animals. This G.I. tract activity was contnbuted chiefly by swatopes of Siort radiological and biological half- life and hmired salubihtv, and thus thelevcls of activity in thetissues of the body were quite low. At 3 months, raciochenucal analyses of tissues from Rongclap pigs medicated that Sré", Balse and the rare carth group constituted 73 per cent of the total internal beta acTapre 3. Rachochemical analvsis of tissues and urine of Rongelap pigs exposed tofallout from the March 1, 1954 nuclear detonation? (from Cohn et al. 1955} Beta activity d/m/total sample % 10°° Skeleton ¢total) oo. ee | Lungs (alveolar) .. Storahy oo cece ceecee cescesse veseseeerneente cas Smal] intestine ooo. cc eee neo Large intestine oo eee Lived occ ce cesses cece ae RIGNOYoe ee cnn cee ce Remaining Carcass a. eco Gross activity Sr* OES (100°; ) 1.3 3.380 (62% J 0.24 16 0.26 25 0.73 29 3.2 4355 0.47 0.18 14 5.0 Ba'*” 595 (6.8%} 0.22 0.62 0.69 2.8 0.27 0.30 Rare earths 850 (9.7% } 0.57 0.40 0.69 4.0 3.9 0.6] ThvP01d dOS8€ oes ceceee eee 200-150 rep (estimated from early analvsis of urine) Total external gamma dOS€ wc. 3301 Internal beta activity Ce, + ue *Nalues are the average of two voung adult pigs which were analyzed 3 months after detonation. 316