The estimated beta or low-energy gamma doses are listed in Table 1 as "shallow" doses, in keeping with the concepts set forth in ICRU 25 (C076). The energy deposited by 90s, in tissue is predominantly within the first centimeter (HA75). The integral 30-year external doses due to betas or low-energy gammas vary from 1/4 to 1/2 of the total external integral doses, depending on the living pattern chosen. The variability is due to differences in 137 ¢6) 9c, and 5, soil concentrations as a function of time on different islands. The integral external doses in Table 1 include no assumptions about modifications which could be made to reduce external dose rates; remedial actions, such as providing gravel around villages or plowing the islands, could very substantially reduce the external shallow dose contribution. 260824956 |