h showed the major portion of activity in their gastrointestinal tract. Based on these studies it was estimated that the amount of radioactive material in the gastrointestinal tract of the more heavily exposed Rongelap group at 1 day post detonation was approximately 3mCi. The initial body burdens of internal emitters in the Rongelap people were estimated from data obtained by radiochemical analysis of the tissues of 2 pigs which had been simultaneously exposed, and subsequent comparison of human and animal urine analyses date (Cohn et al.). Information on the tissue distribution of fission products was obtained from the radiochemical analyses of the pigs living on Rongelap for 1 month. 95% was localized in the skeleton of the pig. Of the internal activity The pattern of deposition of — the fission product mixture in the skeleton, as seen in an autoradiograph of a tibia of 1 of these pigs, resembles that seen after administration of alkaline earths, i.e. dense deposition in epiphyseal region (Figure 5). in the first few months following the acute exposure, 895. and 11 (plus the shorter lived iodine isotopes) contributed the greatest internal radiation dose to the Marshallese. 895, contributed the major portion of the beta dose to the skeleton at this time. The highest dose to an individual tissue (100 to 160 rep) was delivered to the thyroid by the iodine isotopes. Table 3 shows the estimates of the mean body burdens of the Marshallese at 1 and 82 days post exposure. Table 2 Estimated Body Burden of Rongelap People (ic) Activity at isotope __Day| 5r89 pal49 Rare Earth Group 0-1.2 t43l¢in thyroid 6.4-11.2 RuLO3 0-0.013 ca45 5001304 1.6-2.2 0.34-2.7 gland) Fissile Material 0-0.019 0-0.016 (gm) Activity at _Day82 0.19 0.021 0.03 0.0 - 0.0 0.0