PROTRACTED EXPOSURE TO FALLOUT function by a maximum factor of 3 and an average factor of l.o These factors refiec: the quality of fit for directiv measured bod. burden: and urme-derved bocy burdens in genera. The integra! intake tor SQ vr and the commit ted effective dose equivalent were derived cuar- ubes Which depended on knowledge of . and ? for eacn population subgroup The S0- ~ imerval chosen for integral intake representec ine vears 1987-2007 for Rongelap residenis For Utink residents. the S(l-sr interval represented the vears 1984-2004 Tne committed effective dose equivalent was based on this cumulatec intake and both values can be found in Tabie + An important result of using the fitting function was that “Zn and '"Cs were the largest contributors to dose equivalent for each population. The *Zn dose equivalen: was greatest at Lunk because of a three-month interval separaung the BRAVO event and dav of rehabitation and because of the shorter half- life of “Zn. The *Cs dose equivalent is im- portant over the long term. It maybe the chier nuclide of concern during an individual's lifetime post-rehabitation contaminated environment, of a failout- Statistical analysis of data In the cases of "Cs. ©Zn and “Sr. 2 large set of individual adult values for k and P° were available in addition to a set of adult average values. The whole-body counting techniques and urine-bioassav techniques employed were similar throughout the program’s history. The short-term factors influencing the pattern of an individual’s body burden, e.g. sickness, local diet changes, eating imported food, recent trave! to uncontaminated areas, were factors which influenced the pattern of adult average body burden throughout the entire residence interval. Therefore the ratio of the standard deviation to the adult average k’s and P°’s should have been equal to the same ratio for individual adult values. This was in fact the case for "Cs, ®7n and Sr. The standard deviations and the adult average k’s and P°’s for these nuclides were listed in Table 4. Tables of individual adult values were not reproduced here, however, indi- vidual body-burden data obtained in sequence 5012b 1398 are found in the references given in the introduction. These bods burdens mav be used with u fitting function to generate individual adul: Avs and P's. The standard deviations for adult average &°s and P *s were used to estimate the standarc deviations for adult average committed effective dose equivalents (see Table 4) Because the rano of standard deviaguon io the average & and P was the Same for eltner adul. average or indivic- uaiadultk& anc P data for Cs. “Zn and “Sr. 1 was assumea to be true for “Ce and “Fe Thus. the stancaurc deviations for the adult average A, P . 4#evr cumulated intake una commitied effective dose equivalent were estimated and given in Tubie 4 for each of these nuchdes as well. The standard deviation for the 50-yr cumulated intake for each nuclide does not include the deviations due to the variation or uncertainty of biological removal! rate constants. raCioactive decay constants or the fraction of arelement elimimated via the urine pathway. These variations plus the variauion of specific absorbdec fraction of photon energy would introduce even greater standard deviation than that indicated in Table 4 for the esumate of committed eflecuve dose equivalent. External radiation exposure External exposure-rate history curves for pe- riods following resettlement are plotted on Figs. 7 and 8. These exposure rales were manytimes less than the | March 1954 exposure rates 12 hr after detonation of BRAVO. At that ume thev were estimated to average 2.3 x 10° nC kg-'h-' (8.9Rh7') for Rongelap Island. Rongelap Atoll and 8.9 x 10*nCkg™'h7! (0.34Rh7') for Utink Island, Utink Atoll (Le80b). These estimates were extrapolated values based on survey measurements madeseveral days after the BRAVO detonation (OC68). The external exposure at Rongelap and Utirik Atolls since rehabitation varied due to radioactive decay of BRAVO fallout and the addition of low-level contamination from several other nuclear tests (see Figs. 7 and 8). The estimated total 50-yr background subtracted xposure post-rehabitation was 5.9 x 10-*C kg~' (2.3 R) at Rongelap Island and 1.5 x 10-?C kg7! (5.6 R) at Utirik Island. “4 Yo —s 1.4: the “Sr body burdens vaned from the fitted Bh BP maximum factor of | ~ and an average factor of hom >522