MARSHALLESE EX PERIENCE
243
The principal y-photopeaks are those of K®, Zn® , Co® and Cs!9’7, The
spectrum of a member of the medical team of approximately the same age
and body weight obtained at the same time is also shown for comparison.
For the 8-emitter Sr, radiochemical analysis of the urine has pro-
vided data for estimating the body burden. In 1958 an estimate was made
of the equilibrium body burden from the Sr™ /Ca level of the diet.
Strontium-90
The urinary excretion of Sr*° by the exposed Marshallese immediately
after the acute exposure in 1954 is shown in Fig, 3. The Sr*° level in the
urine fell rapidly. The excretion curve over the first three years could be
described by the sum of two exponentials with half-lives of 40 and 500d,
respectively [9]. This latter value for the main component corresponds
with a value of 850 d obtained in a clinical tracer study of parenterally-
administered Sr ®5 Cl, [10].
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TIME (d) AFTER 1. MAR. 1954
Fig. 3
Sr excretion in urine of exposed Rongelap people
The vertical bars represent estimated standard deviation.
The mean body burdens of Sr®° for the Rongelap population from 1954
to 1962 are shown in Fig. 4, On the return of the Marshallese to their home
island, Rongelap, in June 1957, with its persistent low level of contamination, the level of Sr¥%° in the urine increased, reflecting an increased
body burden. In this situation it is clear that ingestion was the primary
route of entry of the contaminant. The estimated mean body burden, as
obtained from the urinalysis data in March 1958 (nine months after their
return),was 2+ 1,02 ne of Sr9¢(9]. This level checks with the values obtained from the bone samples of vertebra and ilium obtained at this time
from a deceased 35-year-old adult male Marshallese. The Sr® level in
these bones was 3.9 pc/g calcium which, when normalized [11] to the whole