years of age ingested more activity each day than did adolescents and persons
greater than 40 years of age.
Maximum deviation from the average value of the
daily activity ingestion rate for members of an age subgroup was no greater than
a factor of 3.
However, the population distributions illustrated a maximum fac-
tor of 5 times the mean activity ingestion rate value.
Dose equivalent rates post-return were determined for members from both
atolls.
For Rongelap Atoll, the residents received approximately 100 to 200
mRem per year during the first 5000 days post-return from internal emitters.
The principal contributing nuclide was 13766.
For Utirik Atoll, the residents
received up to 15 Rem per year during the first 400 days post-return.
contributing nuclides were 6574 and 60c0.
The major
Dose-equivalent rates to the
Utirikese from internal emitters fell below 500 mRem per year at approximately
1200 days post-return.
The dose equivalent for population subgroups and for individuals was determined.
Table 6 summarizes the results for the total body, thyroid, red marrow,
testes, ovaries, lower large intestine wall, and liver.
The catenary compart-
ment model of Bernard and Hayes (Ber70) was used to determine doses to various
segments of the gastrointestinal tract.
The Utirikese received significantly
wore radiation dose from 6574, 6004, and 555, than did the Rongelapese because
of short mean residence times of these nuclides in the environment.
Sr doses
to the Rongelapese were 2.5 time greater and 13706 doses 1.5 times greater than
doses received by persons at Utirik.
This occurred even though Utirik residents
returned to their atoll 3 years earlier and somewhat reflects the degree
to which Utirik was less contaminated than Rongelap.
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