30
+
The value OR,_, =0.25 is an approximate value
obtained experimtentally on rats fed a stock laboratory diet.*? The discrimination factor of 4 for
calcium against strontium from diet to bone in
man has been reported by Schulert’ and Brvant.**
-\ more appropriate value for the rats in this situa-
mate the Sr?” body burdens of the Marshallese
people is also complicated by the uncertaintyof
their diet. The estimates of average dietaryintake
of the Marshallese since their return to Rongelap
are approximate. because the diet has varied dur-
study of wild kangaroo rats living in the Nevada
vielded daily Sr?°/Ca intake levels of 67.5 Sr units
tion might be the ORyone-aie: =0.16 obtained bv a
ee ee
It is obvious that use of this technique to esti-
ing the past several vears. A study made in 1958
desert.**
(uuC Sr°°,’g Ca), provided that coconut crabs(see
The Sr’? body burden is then
Figure +) were excluded from their diet.** *? The
Sr?" /Ca levels in the various foods are shown in
(Sr°°/Ca), =(Sr’?, Ca),(OR,_,)(OR,_,)
The value obtained in this manner is approximately twice the value 470 to 545 wuSr°°/g Ca
obtained by direct radiochemical analysis of the
tissues of rats living on the island during the 2year period following detonation.** This difference
From the discrimination factor of 4 and the daily
between the indirect environmental estimate of
the body burden of Sr**/Ca and the results of
intake of 67.5 Sr units, the equilibrium Sr®° body
burden for the Rongelap people is calculated as
= 17 mypC. This is very close to the equilibrium
direct analysis may reflect either errors in the dis-
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
body burden (23 muC) estimated by Woodward
from the urinalysis data.*°
Another effort was made in the 1959 survgy to
~—
=(8.4x 10°)(0.7)(0.16) =924 uySr°°/g Ca.
Ne. aly,
Table 31. This study was based on the analysis of
various food samples in what mav be considered
an average diet. The data were obtained froma
study of the diets of 14 males on Rongelap.*’ Ir
was assumed that half the calcium in the diet was
derived from food not native to Rongelap Island.
See a
Mise
gather samples of meals to be assayed for Sr*/Ca
content. However, since the Marshallese were
found to subsist to a large extent on foods not indigenous to the area, such as C rations, rice, and
181 wuC Sr9°/g Ca, the life span of the rat is only
== 2 years.
Table 31
Estimate of Sr*’ in Diet of Rongelap Adults, 1958
AxB8
Daily
D
Fraction
intake,*g
content,
Ca
of total
(wet wt)
Meat from mature coconut
Meat from drinking coconut
Milk from green coconut
Pandanus, edible portion
Arrowroot
Breadfruit
Fish
Clams
Crabs, land
Total
89
75
116
79
58
45
139
45
14
mg/2
intake, mg
0.075
2.10.
0.60
0.13
4.00 ©
0.008
1,200
9.6
17.4
11.9
0.022
0.015
1,000
930
22.0
14.0
{21.8
0.132
i9
29
56.0
0.070
27.0
a 18.1
180.0
+.00
660
_
* 449
0.013
0.034
0.023
0,225
0.56
The diet also included imported foods: rice,
canned C rations, flour, tea, milk, salt, and sugar.
*Based on average daily diet of 1+ Rongelap males.*’
**Based on cotal calcium intake of 0.8 g/day.
1185600
210
260
280
5
(+,000)
(
total daily
uuC/gCa
10.5
0.15
0.15
content,
Dx E
Contribution to
Ca intake**
6.7
0.14
£
sre
Sr®* intake, upC/g Ca
2.7
8.8
6.4
1.1
(280.0)
67.5
Ae eRAkin dentedat ee
8B
Ca
NpeE etteetes s ee
A
Daily