burden curve for 90sr, reconstructed from raw data and Eq. more accurate hisfory. 1, was considered a 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 13765 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 in March 1954, it had been proposed that the Hardtack Phase I series 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 the others. Several factors could have contributed to this variation from the mean such as departure and return to the atoll, dietary contribution of imported foods, etc. sickness, the Since the mean values are based on small numbers of persons who were chosen at random, it is conceivable that individuals like 881 M influenced the mean body-burdens to a greater degree than recontamination of the inhabited atollé™ The impact of individual body-burden patterns on the true mean value is moot since the body-burdens of all individuals were not monitored consistently throughout their residence intervals except in the few cases exhibited in Figure 9. 20