C
C:
rate of Cst37 should have resulted in an equilibrated Cs/3! purden, with an
estimated daily intake of about 1560 uuc of Cst3!.
Unfortunately no systematic
survey of foodstuffs grown on these atolls has been reported.
however
Data available,
show that coconut grown on Rongelap contained about 9 uuc cst37 per
gram, and arrowroot (Utirik) contained about 8 uuc Csi37 per gram.
The daily
intake of several hundred grams of either staple would be sufficient to account
for the 1957 excretion level in the Utirik group.
The Rongelap groups had been resettled for about nine months at the time
of the March 1958 medical survey, and urinary excretion levels of cgt3t had
increased about one hundred fold over 1957 levels.
Mean body burden for the
two groups at this time was 0.9 uc (+ 27 percent) and 1.2 uc (+ 47 percent)
(Tables 3 and 4).
Cesium! >! body burden may have equilibrated by late 1958 and
predicted burdens were about 1.3 and 1.6 uc respectively
Strontium’? Excretion Levels and Body Burden
Urinary excretion levels of strontium”? are presented in Tables 1, 2, and 3.
The strontium? excretion level in 1956 was 0.5 uuc/liter as determined in a
pooled sample of 57 liters.
Figure 2 shows the excretion of sr?? for the three
years following fallout exposure.
Although there is considerable variation in
the data for the various age groups at early times, mean values for all groups
plotted suggest that the excretion pattern can be expressed conveniently as the
sum of two exponential terms.
The larger portion of gr?° was excreted with a
half time of about 40 days, and a small fraction, 20 percent, was excreted with a
half time of about 500 days.
This is similar to Cowan's (7) urinary excretion
study of an accident case involving inhaled sr79,
As was noted in the March 1958 cst3! levels, the excretion levels of gr?°
were also increased to 3.5-4.0/0.2, or about 20 fold.
Since csl37 levels in-
creased 4300 - 5200/34, or about 140 fold, the ratio is about seven in favor of
cesium! 3!
With the increases in urinary sr7° excretion levels in 1958, it was