urine activity concentration-to body burden. Equation 3 was obtained by integrating Eq. (2). Equations (1) and (2) were used to determine the instantaneous fraction of atoms removed or added to the stom uptake per unit time, Ker 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 inthe bodyduring the residenceinterval ‘ofanindividual living on Rongelap or Utirik Atoll. | If the mean residence time in the diet is wuch wuch’ eee‘than the resi: oa AM dence interval, then constifbitcontinuous “uptakeis achigved. Halen (1) and ed se a (2) can be converted to: thg’sonstant.continuous saverions by rapaing kK with -\. Single uptake expressions sre obtained by setting ” equalsbolero, In ‘ some cases only radioactive decay may remove the nuclide feom/aihsy items; for ~.: these cases K would equal zero. In the case of the tox £pinevident, i the maturing of coconut trees during residence on Bikini MOLT) caused a con~ tinuously increasing dietary uptake of es, Thus, Ky,as Eound! to have a nege= 1 Yo tive value. pA Bat In the case of Ronge lap and’ Utirix, Ke was found to have a positive value for 1376. 6570, 600, and 905°, This indicated chat in addition to radioactive decay, some other removal mechanism decreased the radipactivity in dietary items during the residence interval. For the nuclide 55 ““Fe, only one mea- surement was published by the BNL Medical Program (Be72); thus an estimate of Kp was not possible. K, was determined by using Eq. (1) or (2) and the population subgroup inean body burden or urine activity concentration. Portions.of these bioassay data are illustrated for adult males and females in Figures 2 to 6. Two consecutive urine or body burden data points were used to eliminate the unknown ingestion TON RTE ween TERN LL ey ere