ay yal} roadie yabl len Ge LU one. ' . ‘ ' taal : 4 vy al oy Vey. ve Sui: the male value for Re wouldbe“different from the female value by’ the’ factor observed. ° +e we of urine activity concentration variability, there was 4 602'probability that lig, 3 we yk Tg ee he Thus differences in the derived activity ingestion rates and dose . . tae equivalents were not significant. iF Figure 14 shows a semi-log plot of the 652, and 137c6 activity: ingestion rate histories for adultes on Rongelap. A curve was drawn betweenpoints, and the appearance of an increasing’ !°’Cs ingestion rate duringthe"1960's" indicated the possibility of another contaminating event. The Hardtack Phase I series was conducted just prior to the observed increase in the curve and fallout from the Cactus, Yellow Wood, end Hickory experiments detonated at Bikini and Enewetak would have reached Rongelap. However, several observations fail to support the conclusion that recontamination was significant. These are ‘as follows: 1) the increase in !3’¢5 ingestion rate was not in conjunction with an increase of 6300; however, since 6575 is an activation product it may have not been produce)! in the same proportions. 2) The peak 1370. body burden at Utirik occurred nearly three years after the initiating event, Castle BRAVO, while the peak badly burden at Rongelap followed six years after the potentially contaminating experi ~ ments of the Hardtack series in 1958. 3) The activity ingestion rate at Utirik demonstrated a continuously declining pattern vereus the humped pattern observ-:l a at Rongelap. oe This occurred even though there was an equal external exposure rate history following the Hardtack series as measured by the U.S. Public Healii: Service on both Rongelap and Utirik (Un59). 4) The peak exposure rate on Rongelap following the Hardtack series was 10,000 times less than the peak exjpu~ sure rate following BRAVO. These facts suggest that the Hardtack series was noi a major factor influencing the Rongelap bady burden patterns. Thus it is postulated that body burden variations were caused by travel away from the atrj! 29 oS eerTne o