years of age ingested more activity each day. thandidadolescents andpersons greater than 40 years of age. Maximum deviation from the average value of the daily activity ingestion rate foxr.members of an agesubgroup was no greater than a factor of 3. = However, the population distributions illustrated a maximum fac- aes tor of 5 times the mean activity ingeation rate value. 11: , a mos a Dose equivalent rates post return were determined for members from both oe atolls, For Rongelap Atoll, the residents received approximately 100 to 200 mRem per year during the Cirae 5000 days post return from ‘internal ewitters.’ l The principal contributing nuclide win } 3o6, For Utirik Atoll, the residents received up to 15 Rem per year during the First 400 days past return, contributing nuclides were 6574 and 6004, The major Dose equivalent:rates to the Utirikese from internal emitters fell below 50Q mRem per yeer at approximately 1200 days post return. reget, - . vos‘ w The dose equivalent for population subgraqups and for individuals was deter: mined. Table 6 summarizes the results for the total body, thyroid, redmarrow, testes, ovaries, lower large intestine wall, and liver. The cetenary compart- ment model of Bernard and Hayes (Ber70) was used to determine doses to various segments of the gastrointestinal tract. The Ucirikese received significantly more radiation dose from 6528, 6000, and 9556 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 d doses received by persons at Utirik. 37 905, doses Cs doses 1.5 times greater than This occurred even though Utirik residentc returned to their atoll 3 years earlier and somewhat reflects the degree og to which Utirik was less contaminated than Rongelap. li 51 oF oil ua ‘ ate as mare aye ere oe ” es - at v