—
30
It is obvious that use of this techniqueto estimate the Sr°" body burdens of the Marshallese
people is also complicated by the uncertainty of
their diet. The estimates of average dietary intake
of the Marshallese since their return to Rongelap
The value OR,_, =0.25 is an approximate value
obtained experimentally on rats fed a stock labo-
ratory diet.‘? The discrimination factorof 4 for
calcium against strontium from diet to bonein
man has been reported by Schulert** and Bryant.**
A more appropriate valuefor the rats in this situa-
are approximate, because the diet has varied during the past several years. A study made in 1958
yielded daily Sr°°/Ca intake levels of 67.5 Sr units
(wuC Sr°°/g Ca), provided that coconut crabs (see
Figure 4) were excluded from their diet.**-** The
Sr°°/Ca levels in the various foods are shownin
Table 31. This study was based on the analysis of
tion might be the ORyone-aier = 0.16 obtained by a
study of wild kangaroorats living in the Nevada
desert.**
The Sr*° body burdenis then
(Sr®°/Ca),=(Sr°°/Ca),(OR,_,)(OR,_,)
=(8.4 10°)(0.7)(0.16) =924 uC Sr°*/g Ca.
various food samples in what may be considered
an averagediet. The data were obtained froma
The value obtained in this manner is approximately twice the value 470 to 545 puC Sr°°/g Ca
obtained by direct radiochemicalanalysis of the
tissues of rats living on the island during the 2year period following detonation.*® This difference
between the indirect environmental estimate of
the body burden of Sr®°/Ca and the results of
direct analysis mayreflect either errors in the dis-
study of the diets of 14 males on Rongelap.*’ It
was assumedthat half the calcium in the diet was
derived from food not native to Rongelap Island.
From the discrimination factor of 4 and the daily
intake of 67.5 Sr units, the equilibrium Sr*° body
burden for the Rongelap people is calculated as
= 17 muC. This is very close to the equilibrium
body burden (23 mpC) estimated by Woodward
from the urinalysis data.*°
Anothereffort was made in the 1959 survey to
crimination ratios or perhaps lack of equilibrium
between the Sr°°/Ca in the animals and in the
soil at 2 years. The latter possibility exists, since,
although the 13 adult rats analyzed by Held*’ at
4 years had valuesclose to the 2-year level, 443+
181 wuC Sr®?/g Ca, the life span of the rat is only
=2 years.
gather samples of meals to be assayed for Sr*°/Ca
content. However, since the Marshallese were
foundto subsist to a large extent on foodsnotindigenous to the area, such as C rations, rice, and
Table 31
Estimate of Sr°* in Diet of Rongelap Adults, 1958
A
Meat from mature coconut
Meat from drinking coconut
Milk from green coconut
Pandanus, edible portion
Arrowroot
Breadfruit
Fish
Clams
Crabs, land
Total
B
AXB
Daily
intake,* g
(wet wt)
Ca
content,
mg/g
89
75
0.075
0.14
6.7
10.5
79
58
45
139
45
14
0.15
2.10
0.60
0.13
4.00
4.00
11.9
121.8
27.0
18.1
180.0
56.0
116
Daily
Ca
intake,mg
0.15
660
17.4
449
D
Fraction
of total
Caintake**
0.008
0.013
0.022
0.015
0.152
0.034
0.023
0.225
0.070
0.56
E
Sr?
content,
pyC/gCa
1,200
210
1,000
930
19
260
280
5
(4,000)
DXE
Contribution to
total daily
Sr*° intake, nC /g Ca
9.6
2.7
22.0
14.0
2.9
8.8
6.4
1.1
(280.0)
67.5
The diet also included imported foods: rice,
*Based on average daily diet of 14 Rongelap males.*’
** Based on total calcium intake of 0.8 g/day.
roe
canned C rations, flour, tea, milk, salt, and sugar.