. — The unmodified expected mean population doses obtained by averaging cases Saend Ip; II, III and IV are all quite comparable with typical USA values. At most, implementation of modifications 1. and 2. should be sufficient to Wee assure mean ‘population exposures well below U. S. mean levels. pa Because of the Low amount of natural radioactivity normally present in oe. coral atolls, these levels would still of course be higher than levels found elsewhere in the Marshall Islands (essentially case IV). The results for cases II and IV indicate restricting the permanent villages to "clean" southern islands at least temporarily would also result in lower exposures, recalling that the calculations are based on an immediate return. Note that for case Ip almost as much exposure is accumulated in the first 10 . years as in the succeeding 20 years: As illustrated in Table V for case I, differences in radiation exposure of the various population groups are 3 _minor, particularly for the longer time periods. Similar results were obtained for the other cases indicating that the exact time breakdown among é ‘age groups is not highly important. a) The fact that the doses for cases Ip and Ip do not differ substantially indicates the exact time breakdown among geographical areas is also not critical. . way * 8 ets 7 . we eR OAT OA COTE repemreapnpurens CaS