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, 6570, 60 c0, 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 23954 was 7.5x107> + 9.1x10> at, For 5356, 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 cumu lated 97 Fe intake, k was assumed equal to zero which implies that radioactive decay was the only cause of reduced daily activity intake during residence. Where data were available for comparison, the values for k for 1370, and Os, were found to be similar for both males and females as well as for resi- dents 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 13766 for each year at Rongelap and Utirik. For dietary 905, an 8% reduction was estimated for each year at Rongelap and Utirik. The 60 60 and a intakes were reduced rapidly during the first few years post return to Rongelap Atoll. An 80% per year reduction in dietary 672 and a 60% per year reduction in dietary 0 Co were observed for adults. Also, for adult males at Rongelap, a 14