we Figure 4 and figure 6 illustrate the observed adult histories of 705, and 1376. mean urine activity concentrations. adults were plotted. figure 7. Mean values for adult males or all Measured values for 1376, body burdens were also shown in A much smoother curve was plotted in figure 7? and it was determined that the collection and analysis technique for urine samples introduced the additional variations. Based on this observation for 137¢,, a smooth body burden curve for 906, reconstructed from raw data and equation 1, was considered a more accurate history. A detailed presentation of the greater variation in urine bioassay measurements versus direct body burden measurements can be found in Mi8l. Figure 9 illustrates the variation exhibited in the body burden of 5 randomly chosen subjects over the 25 year monitoring period. variations may have had a dramatic impact on the mean data. These individual In figure 2, which illustrates the adult male, adult female and adult population mean 13704 body burden for the 25 year exposure period, a decrease followed by an increase was seen during the years 1958 through 1963. Although the Castle BRAVO test ini- tially contaminated Rongelap, it had been proprosed that the Hardtack Phase I se- ries added to this an amount of contamination equal to that responsible for the figure 2 body burden pattern (Co63). Figure 9 suggests that most individuals counted in those years had maintained or declined in body burden; however, one individual's burden (#881 M) rose and fell quite differently from theothers. Several factors could have contributed to this variation from the mean such as departure and return to the atoll, sickness, the dietary contribution of imported foods, etc.. Since the mean values sre based on small numbers of per- sons who were chosen at random, it is conceivable that individuals like 881 M 10