Estimates of the Radiological Dose
from Ingestion of 137Cs and 90Sr to
Infants, Children, and Adults
in the Marshall Islands
Abstract
In this report, we examine whether the radiological dose equivalent due to the
intake of 137Cs and 90Sr at a contaminated atoll in the Marshall Islands would be
greater when intake begins as an adult than when intake begins as an infant or
child. We found that generally 137Cs contributes 97 to 98% of the dose and 99Sr
contributes only 2 to 3%. Wealso foundthat the integral 30-, 50-, and 70-y effective
dose equivalent estimated for intake beginning as adults is greater than that for intake beginning at any other age. There are two factors that cause the adult
estimated dose to be greater than the dose to infants and children. The major factor
is the consistently higher intake of local foods, and consequently higher intake of
137Cs, for adults. The second is a combination of changing body weights, fractional
deposits, and biologicalhalf-life for 137Cs with age, and the reduced concentration of
137Cs in food with time.
Consequently, the estimated effective integral dose
equivalents for adults due to ingestion of !37Cs and 99Sr can be used as a
conservative estimate for intake beginning in infancy and childhood.
Introduction
The purpose of this report is to determine
whether the radiological dose equivalent due to
the intake of 197Cs and Sr at a contaminated
atoll in the Marshall Islands would be greater
when intake begins as an adult than when
intake begins as an infant or child.
In previous publications, we have estimated
the radiological doses to adults at several atolls
in the northern Marshall Islands resulting from
external gamma exposure and internal ingestion
of 1387Cg 90S, , 239+240Py and 241 Am (Robison
etal., 1982a, 1982b, 1987; Robison, 1983). We
have mentioned in all of these reports that the
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radiological dose from the ingestion of !37Cs
and %0Sr beginning in infancy or early childhood
would lead to 30- and 50-y integral doses that
are about the same or less than similar doses
estimated for intake beginning as an adult.
These staternents were based on dietary data for
the daily intake of 137Cs and 9%Sr at the
Marshall Islands, differences in physiological
parameters (such as biological half-life and
deposition patterns for !3’Cs and 90Sr), body
mass as a function of age, and dosimetry; we
published a preliminary evaluation of the
relative estimated radiological doses -for