CHAPTER IV Internal Contamination of Animals At the time of the fallout on Rongelap Island there were a variety of animals present. These were left to live on the island, and representative numbers were collected on the &th, 25th, 33rd, and 5lst-53rd days and then sacrificed. Tables 36, 37, and 38 show the relevant data concerning external doses to the animals while living on the island, and an analysis of their internal contamination.® Over 90 percent of the activity in the body of animals was in the skeleton. At 82 days past detonation, 62 percent of the skeletal beta activity of the pigs was due to Sr®, 7 percent Ba’, and 10 percent rare earth group. However, it was reported that ‘... In the 6 months period post detonation neither significant gross changes nor pathological changes which could be definitely ascribed to radiation were detected in any of the animals.’ ® Table 39 shows the activity of a rooster and rats collected 2 years post detonation.* The gross activity in this rooster was 40 percent of that of a rooster from the samelocality at 1 year post detonation. Since these animals represented interesting cases of living continuously in a heavily contaminated environment, a strontium-90 analysis was madelater of some rats and a rooster collected at the 2-year period. (Table 40).° Additional analysis was made by AFL of a single rat bone specimen (Table 40). These data are extensive but do indicate the relatively low body burden of strontium-90. 38