years of age ingested more activity each day thandidadolescentsandpereons greater than 40 years of age. Maximum deviation from the average value of the daily activity ingestion rate for.members of an agesubgroup was no greater than a factor of 3. However, the population distributiens illustrated a maximum fac~ ‘ tor of 5 times the mean activity ingeation rate value. . ©. ::: mek Dose equivalent rates post return were determined for members from both atolls. For Rongelap Atoll, the residents received approximately 100 to 200 mRem per year during the firse $000 days post return from internal emitters, The principal contributing nuclide was 1370,, For Utirik Atoll, the residents teceived up to 15 Rem per year during the first 400 days past return, contributing nuclides were 6575 and 600, The major Dose equivalent ;ratas to the Utirikese from internal emitters fell below 500 mRem per year at approximately . 1200 days post return, a wh, ' . : The dose equivalent for population subgroups and for individuals was det: + mined. Table 6 summarizes the results for the total body, thyroid, red. marrow, testes, ovaries, lower large intestine wall, and liver. The catenary compart~ ment model of Bernard and Hayes (Ber/0) was used to determine doses to various segments of the gastrointestinal tract. The Utirikese received significantly more radiation dose from 6524, 606, and 4556 than did the Rongelapese because of short mean residence times of these nuclides in the environment. . to the Rongelapese were 2.5 time greater and doses received by persons at Utirik. 137 905. doses . Cs doses 1.5 times greater thai This occurred even though Utirik residen:: returned to their atoll J years earlier and somewhat reflects the degree to which Utirik was less contaminated than Rongelap. 51 ey soe mh Be eoarng aye eae é mg