168 Age: n+1 years August 2010, Volume 99, Number 2 Age: n+2 years usual 20 g assumption. These modestly larger thyroid masses were used in the derivation of the thyroid dose coefficients, consistent with findings by Zvonova (1989) oy , LAA? AMAA > XS OOOO S 5050505 oS ROCKY o52505 and others. The dose coefficients due to ingestion of '*'l $2509 SSR arate 3 “$< 3 Dose Rate Age: nyears I I Teston 1 January Health Physics are presented in Table 5. The dose coefficient derived for % RRR X KO an seansososeeerereneeseeeesMOROCCOee thyroid due to ingestion of "I is about 10% higher for EREOo rx) ox LY adults in our study, compared to the ICRP default dose coefficients. In addition to the thyroid mass differences, other differences in the kinetic parameters (Table Al) Dose Rate Year 3 accountfor the small differences in the dose coefficients. Special consideration wasgivento the calculation of the annual dose coefficients for infants as follows. (1) As previously indicated, two sources of exposure were considered for infants: acute intake of deposited fallout and SOO PD “, I S555 oe POCO S502 KIO RD POORKIRA ROR KT Pee > be BES Be5C5505 SZ SKXRBO (Ay ROSSERKO HKOe, ; S4 ORY i ; BSSSCCoC: ZZ consumption of breast milk, contaminated asthe result of acute intake of fallout by the mother. Assumptions we made to complete these calculations included: Year 3 Dose Rate e The mother’s acute intake was calculated using eqn. (4); e The fractions of radionuclides ingested by the mother that are transferred to the infant in breast milk were taken from ICRP Publication 95 (2004) for the radio- Year 1 Year 2 Year 3 Fig. 1. Change of the dose rate as a function of time after a nuclear weaponstest and its effect on the dose within a given calendar year using *’Sr as an example; for test dates occurringlater in the year, the dose delivered from the TOI to the end of the calendar year is smaller, while the doses delivered in subsequent years are greater; however, the lifetime dose remains the same. nuclides of 35 elements. For the 15 elements that are not considered in the ICRP report, the fractional transfer factors were estimated from a relationship we derived between the reported fractions transferred to the infant in breast milk (ICRP 2004) and the reported alimentary tract absorption fractions (f,) in the mother as adopted by ICRP in its Publication 72 for the 35 elements with available data (ICRP 1996). The rela- tionship, given in eqn (10), is illustrated in Fig. 2: Fim = 0.0854 X (f,)!-08!, (10) The estimated values of F,,,, for the 15 elements not considered by ICRP (2004) are presented in Table 6. Table 5. Absorbed doseper unit intake of '*’I used to estimate organ absorbed dose to representative persons ofsix age groups of Marshallese plus military personnel from acute ingestion of radionuclides. ICRP (1996) values for the public are presented for comparison. Dose coefficient for ingestion of I (Gy Bq™') Group Age (y) Marshallese Marshallese Marshallese Marshallese Marshallese Marshallese Marshallese Military personnel® Public? <1 <1 lto <3 3 to <8 8 to <13 13 to <18 =18 (adult) =18 (adult) =18 (adult) Red marrow 5.3 x 1.8 x 3.9 x 2.4x 1.7 x 1.3 x 1.1 x 9.8 x 1.0 x 10°71 19071 10° 19° 107° 197'° 107'° 107! 107'° Thyroid 3.7 x 1.2 x 3.6 x 2.1 X 1.0 x 6.7 X 47x 4.3 x 4.3 x 10° 107% 10°° 107° 107° 1077 107 107 107 Stomach wall 3.5 1.1 2.0 9.8 5.6 3.8 3.0 3.0 3.0 x x X x xX x x x x 107% 107% 10°? 107% 107% 10°! 10° 10°" 10° Colon 3.0 9.8 1.7 7.0 2.8 1.6 1.2 1.0 1.2 x x x x x x x x x 107% 1971 10° 10° 10° 10° 10° 107° 10° * Dose coefficient for infants for direct ingestion of fallout (Gy Bq' intake). > Dose coefficient for infants for ingestion of breast milk (Gy Bq”! of mother’s intake). “ Dose coefficients derived based on the physiological parameters presented in Table Al. “ Dose coefficients for ingestion derived for adults in the general public (assuming physiologic and anthropometric characteristics of Western Europeans and North Americans) from ICRP (1996).