‘ ‘ a Dot aeay 5 veh yi eodto, oS worey 3 ve bg Ye octa of urine activity concentration variability, ‘there was a 60% probability that tig! ‘ lee : Le ‘ iy bey. . wi the male value for Ke would be‘different ftom the female value by the factor observed. Thus differences in the derived activity ingestion rates and dose ‘ : ‘ge oe equivalents were not significant. Figure 14 shows a semi-log plot of the 6575 and 137c, activityingestion rate histories for adults on Rongelap. A curve was drawn betweenpoints, and the appearance of an increasing 1376, ingestion rate duringthe’ 1960'sindicat«d the possibility of another contaminating event. The Hardtack Phase I series wis conducted just prior to the observed increase in the curve and fallout from the Cactus, Yellow Wood, and Hickory experiments detonated at Bikini and Enewetak would have reached Rongelap. However, several observations fail to support the conclusion that recontamination was significant, These dre as follows: increase in 137 1) the Cs ingestion rate was not in conjunction with an increase of 8500; however, since 652, is an activation product it may have not been produce! in the same proportions. 2) The peak 1376, body burden at Utirik occurred nearly three years after the initiating event, Castle BRAVO, while the peak bo.ly burden at Rongelap followed six years after the potentially contaminating expr: ments of the Hardtack series in 1958. 3) The activity ingestion rate at Utirik demonstrated a continuously declining pattern versus the humped pattern observ: at Rongelap. 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 ‘ g ai 4 a a4 a Rongelap following the Hardtack series was 10,000 times less than the peak expo sure rate following BRAVO. These facts suggest that the Hardtack series was tio: a major factor influencing the Rongelap body burden patterns. Thus it is postulated that body burden variations were caused by travel away from the ati 29 TPE?! OSESOY aoe ? 2 ‘4 2 ’ a i