116 Health Physics corrected for fractionation, (3) estimation of the deposi- tion density of '’Cs followmg each of 20 tests on all inhabitedatolls, (4) estrmation ofthe mtake of "Csatall August 2010, Volume 99, Number 2 uptake and, to a lesser degree, madvertent consumption of soil (Stmon 1998, Simon et al 2010) A previous assessment (Lessard et al 1984) showedthat five radio- mhabited atolls assummg that the ratio of mtake to nuchdes account for essentially all the mternal dose from intakes of all radionuchdes considered at all mhabited The available historical whole-body counting and bioassay measurements were used as a basis to estimate the chronic mtakes smce a suitable dietary model coverimg the many yearsafter the tests, when lifestyles became deposition was the same at all atolls, (5) estrmation of atolls following each nuclear test, and (6) estmation of annual and cumulative radiation absorbed doses to four organs (RBM, thyroid, stomach, colon) of representative persons for all relevant birth years Detailed mformation on the acute mtakes and resultimg doses, as well as the estrmated uncertamty in these dose estimates, 1s presented m Simon et al (2010) The population of the southern atolls had acute mtakes estimated to be much smaller than those experienced by the more highly exposed Rongelap and Utrik populatons For example, adult Mayuro residents had imtakes of about 6% and 9% of the "I and '’Cs (cumulative over all tests), respectively, of adult Utmk commumty mem- bers, and about 1%, and 2%, respectively, of the mtakes of Rongelap community members exposed to Castle Bravo fallout on Rongelap Island (see Table 8, S1monet al 2010) Doses to the thyroid gland were much greater than those to the other organs and tissues, and were much greater for the Marshallese who resided on Rongelap and Utnik Atolls at the tme of the Castle Bravo test than for the residents of any other atoll (Table 10, Simon etal 2010) The southern atolls, where about 73% of the population resided durmg the testing years, recerved the lowest organ doses The population of mid-latitudeatolls (Kwayalein and others, see Fig 2), home to about 23% of the total Marshall Islands population durmg the testing years, received organ doses that were about three times greater than at the southern atolls The population of Utnkreceived doses intermediate m magnitude between the mid-latitude atolls and Rongelap, with thyroid doses about 35 timesgreater than the southern atolls (Table 10, Simon et al 2010) The Rongelap Island communtty received the Inghest doses, with thyroid doses about 350 to 400 umes greater than those received m the southern atolls Internal doses from chronic intakes of radionuclides. Following the deposition of radionuchdes on the ground, chromc (1, protracted) mtakes took place at rates much lower than those due to the acute mtakes While both acute and chronic intakes were primarily a result of mgestion, the environmental transport processes leading to chrome mtakes were substantially different from those that gave rise to acute mtakes Chrome intakes were primarily a function of the consumption of seafood and oflocally grown terrestrial foodstuffs imternally contammated with long-hved radionuchdes via root chrome mtake “Fe, Co, “Zn, Sr, and '’Cs more westermzed, does not exist Those whole-body and bioassay measurements were made on the Rongelap and Utrik evacuees for years after they returned to their respective home atolls (Lessard et al 1984) The Rongelap and Utrk populations, who were evacuated withm about two days followmg the detonation of the Castle Bravo test on 1 March 1954, were retumedto their home atolls m June 1957 and June 1954, respectively (Table 3) Durmg the first few weeks after ther return and until the 1980's, a Brookhaven National Laboratory team regularly conducted measurements of whole-body activity of “Cs, “Co and “Zn, as well as urmary concentrations of “Sr Measurements of *Fe m blood were also performed, but only once (Lessard et al 1984) The steps used to estrmate the doses from chromic mtakes of radionuchdes were (1) estimation of the chromc mtakes by Rongelap and Utrk adult evacuees due to the Bravo test, (2) estmmation of the chromc intakes resultmg from the Bravo test by adults ofall other atolls, based on the relative ‘Cs deposition, (3) estrmation ofthe chronic intakes by adults resultmg from tests other than Bravo, agam based on relative *’Cs depost- tion, (4) estimation of the chromc mtakes by children, and (5) estrmation of the doses from chromic intakes from all tests and all population groups usmg International Commission on Radiogical Protection recommended dose coefficients Detailed mformation on the estimation of chromc imtakes and resulting doses 1s presented m Simonet al (2010) The doses from chronic intakes show the same geographical pattern as the doses resultmg from acute intakes and '*’Cs deposition (Fig 2) However, because of the absence of short-hved iodine isotopes which dommiated the thyroid dose from the acute mtakes, the thyroid doses from chromc intakes were not much greater than the doses to other organs and tissues Similar to the situation for acute mtakes (Simonet al 2010), only a few radionuchdes contributed most of the organ absorbed dose For all organs and for all four of the atoll and population groups discussed, Cs was either the first or second most rmportant contributor to imternal dose from chromic mtakes For the evacuated Rongelap Island commumity, °’Cs was the most important contrib- utor to the chromic dose, whereas Zn was the largest