patterns. Thus it is assumed that persons with body-burdens significantly dif- ferent from the mean body-burden for the population caused the extent of variation reported. On the basis of these observations, a smooth description of the body~burden and activity ingestion rate was adopted and a declining continuous uptake model was used to generate the curves in Figures 7 and 8. Internal Dose Equivalent Rates The approximate instantaneous dose equivalent rates for the total body were determined from the body-burden data illustrated in Figures 7 and 8 and from the following equation H = qI, (4) at me where the total body dose equivalent rate, mRem yal, I = equilibrium dose equivalent rate to the total body per unit body~ burden, mRem y7) ucinl, q = instanteous body-burden, LCi. The approximate nature of the estimate was due to the assumption that the radioactive atoms were distributed among the body tissues as they would be following constant continuous uptake for periods of time much greater than the mean . . residence time for the total body. assumed. a 90 tqeucs In sie case of Sr, 86% of equilibrium was These assumptions were not used in the estimate of the total dose equivalent. In addition, since mean adult body-burdens were computed, a factor of 1.2 was needed to adjust for differences in body mass relative to a 70-kg adult. Table 5 lists values of I which were determined from information given in ICRP59 and corrected for body mass differences. 30