50
5
The value OR,_, =0.25 is an approximate value
[t is obvious that use of this technique to esti-
obtained expertmientallyon rats fed a stock laboratory diet.** The discrimination factor of 4 for
mate the Sr°® body burdens of the Marshallese
people is also complicated by the uncertainty of
their diet. The esumates of average dietary intake
of the Marshallese since their return to Rongelap
calclum against strontium from diet to bone in
man has been reported by Schulert*’ and Brvant.*!
A more appropriate value tor the rats in this situa-
are approximate, because the diet has varied dur-
tion might be the ORyyae-a:e1=0.16 obtained bya
study of wild kangaroo rats living in the Nevada
ing the past several vears. A study made in 1958
yielded daily Sr°’//Ca intake levels of 67.5 Sr units
(Sr°°/Ca), = (Sr? /Caj),(OR,_,)(OR,_,)
Sr°° Ca levels in the various foods are shown in
(upC Sr°"'¢ Ca), provided that coconut crabs(see
desert.*”
The Sr*® body burdenis then
Figure +) were excluded from their diet.** ** The
Table 31. This study was based on the analysis of
various food samples in what may be considered
=(8.4x 10")(0.7)(0.16) =924 uC Sr°*/g Ca.
The value obtained in this manneris approxiobtained by direct radiochemical analysis of the
was assumed that half the calcium in the diet was
derived from food not native to Rongelap Island.
between the indirect environmental estimate of
intake of 67.5 Sr units, the equilibrium Sr°° body
burden for the Rongelap people is calculated as
tissues of rats living on the island during the 2year period following detonation.** This difference
From the discrimination factor of 4 and the daily
the body burden of Sr?°/Ca and the results of
direct analysis may reflect either errors in the discrimination ratios or perhapslack of equilibrium
between the Sr®°/Ca in the animals and in the
=17 mpC. This is very close to the equilibrium
body burden (23 muC) estimated by Woodward
from the urinalysis data.°°
although the 13 adult rats analyzed by Held*’ at
+ years had values close to the 2-year level, 443
181 wu 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
found to subsist to a large extent on foods notindigenous to the area, such as C rations, rice, and
soil at 2 years. The latter possibility exists, since,
*(
r
2
=’, J
ok emma ee
an average diet. The data were obtained froma
study of the diets of 14 males on Rongelap.*’ It
mately twice the value 470 to 545 uC Sr°?/g Ca
Spee ees a
I
Mie
Another effort was made inthe 1959 survey to.”
’
Table 31
Estimate of Sr?? in Diet of Rongelap Adults, 1958
A
Daily
intake,* e@
(wet wt) -
Meatfrom mature coconut
Meat from drinking coconut
Milk from green coconut
Pandanus, edible portion
Arrowroot
89
75
116
79
58
B
Ca
content,
me/g
0.075
0.60
0.13
Crabs, land
14
4.00
Total
6.7
10.5
17.4
11.9
2.10,
45
139
45
Ca
intake,mg
0.14
0.15
0.15
Breadfruit
Fish
Clams
AXB
Daily
4.00 ©
660
121.8
D
Fraction
oftotal
Caintake**
~ 9.008
0.013
0.022
0.015
0.152
27.0
18.1
0.03+
0.023
36.0
0.070
” 449
0.36
a
180.0
0.225
E
Sr?
content,
puC/gCa
DXE
Contribution to
total daily
Srintake, pyuC/g Ca
1,200
9.6
210
1,000
930
2.7
22.0
14.0
19
2.3
260
280
5
(4,000)
(
.
8.8
6.4
Lt
(280.0)
67.5
The diet also included imported foods: rice,
canned C rations, flour, tea, milk, salt, and sugar.
[ORESet Ge gera es
*Based on average daily diet of 14 Rongelap males. *”
** Based on total calcium intake of 0.8 g/day.