Pa traction from GI tract to blood, fT = fraction excreted by the urine pathway, Kg = instantaneous fraction of atoms removed or added to the atom uptake per unit Cime, day!, q = instantaneous body burden, Bq, q° = body burden at the onset of uptake, Bq, D = the number of disintegrations in all compartments occurring during the uptake interval, Bq days. Equations 1 and 2 were used to determine the dietary removal rate constant K,. and then the initial daily activity ingestion rate required to produce the measured or derived body burden. Equation 3 was used to determine the number of disintegrations that occurred in the body during the residence interval of an individual living on Rongelap or Utirik Atoll. DETERMINATION OF Ke If the mean residence time in the diet is much much longer than the residence interval, then constant continuous uptake is achieved. Equations 1 and 2 can be converted to the constant continuous equations by replacing Ke with -A. Single uptake expressions are obtained by setting P®° equal to zero, In some cases only radioactive decay may remove the nuclide from dietary items; for these cases Kg would equal zero. In the case of the former Bikini regidents, the maturing of coconut trees during regidence on Bikini Atoll caused a continuously increasing dietary uptake of 1370, negative value. Thus, Ke was found to have a In the case of Rongelap and Utirik, Ke was found to have a posi- tive value for 1376.4 ’ 6575 3 600, and 905,, This indicated that in addition to radioactive decay, some other removal mechanism decreased the radioactivity in