_ Using this metho? with the Rongelap data, t*2 average 55556 body burdens agreed within 15 per cent of those calculated using body weights. Table 1 gives the average body burdens of She in a selected group of Rongelapese sampled in March, 1970, and Figure 1 shows | a frequency distribution of the body burdens of males and females. Tron-55 levels in the blood samples were sufficiently high to permit count rate measurements to + 5 per cent at the 95 per cent (20) confidence level. Not_all donors were weighed in 1970, therefore body weights from previous years were used to compute total blood volunes. However, weights from previous years applied mostly to younger donors. Since weight generally in- creases with age, some individual estimates of ene body burdens, and therefore the averages shown in Table 1, are likely to be - conservative. The maximum body burden in the males was 0.85 uci, while three females had body burdens greater than this value. The max tmum observed female body burden was 1.0 UCi, approximately '1/100th of the maximum permissible body burden which has been established for non-occupationally exposed individuals considering the total body as the critical organ (18). Previous measurements of aor body burdens during a period of increasing ar fallout generally showed that 5° re body burdens of females were higher than those of males (4,5). Presumably this is due to higher Fivenceee