year period. The standard deviation was in general 30% of the mean value for all age and sex subgroup distributions. the fact that 65 This less pronounced variation may be due tu “Zn measurements took place over a 3 year interval while 90 Sr and 1376, occurred over a 23 year interval and thus was contained in a more homogeneous population than were the longer lived nuclides. , ys ” 90 Figures 22 and 23a and 23b summarize the Sr dose equivalent results for individuals at Rongelap. In this analysis, only the ingestion pathway was considered important. Some radioactivity would enter the body via the resuspension and direct inhilia- tion pathways. It is known that for a given soil concentration of ‘the stab! naturally occurring analogs to the radiopuclides considered here, the ratios fe Lf Co > 3000 Zn > 130 Fe > 550 Sr > 10,000 Cs > 400 Thus, dietary intake of radioactive material is the principal pathway leadiiz to This applies to most nuclides in the environment, how ver, there are notable exceptiona including I, U, and Pu, one meter above the surface, was used to convert exposure in air to absorbe! Jose in tissue. The source was assumed to be an exponential distribution of a7, acu tivity with depth in soil, typical of aged fallout (Be70). Because of the multidirectional nature of the source, variation of absorbed dose with depth of organ was minimal. Additionally, external doses were adjusted for living pit - 43 “oe A value of .73 rads in tissue of interest per rontgen, measured in aii 11 ahaa ae bees External Exposure Pie Lede ow, internal deposition, Vee eeuS osaf tte follows: ne as Se Se ee ney of food and fluid intake to blood relative to airborne intake to blood, are