fluctuations, 2) movement of adults in the study population to a clean island or atoll for a month's visit with family or friends and 3) to the initial success and subsequent failure of a food subsidy program which began at Rongelap in 1958 (Co80b). Derived Quantities The k values calculated for each nuclide in the Rongelap and Utirik adult populations are given in Table 4. In the cases of the Rongelap and Utirik peo- ple for whom sequential body-burden data was available, k was found to have a positive value for 13766, 6574, 6960, 2395, and 905. The 2395, data for urine of three adult males at Rongelap in 1973 and 1976 provided a single tentative estimate of k. The value of k for 2395, was 7.5x10> + 9.1x107> at, For 33 Fe, only one bioassay estimate was published as a result of studies by the BNL medical program (Be72, Co75); thus an estimate of k was not possible. For the esti- mate of cumulated 93 Fe intake, k was assumed equal to zero which implies that tadioactive decay was the only cause of reduced daily activity intake during residence. Where data were available for comparison, the values for k for 1376, and Os, were found to be similar for both males and females as well as for residents of both Rongelap and Utirik. The yearly per cent decrease in the atom in- gestion rate was computed using Eq. 3 and the derived k value for each nuclide of interest. This intake relationship shows a 9% reduction in dietary 13765 for each year at Rongelap and Utirik. For dietary 905, an 8% reduction was estimated for each year at Rongelap and Utirik. The 606, and 6570 intakes were reduced rapidly during the first few years post return to Rongelap Atoll. An 80% per year reduction in dietary 675 and a 60% per year reduction in dietary 60 Co were observed for adults. Also, for adult males at Rongelap, 14 a