30
It is obvious that use of this techniquetoestimate the Sr®° body burdensof 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
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
(upc Sr*°/g Ca), provided that coconut crabs(see
Figure 4) were excluded from their diet.**-** The
The value OR,_,=0.25 is an approximate value
obtained experimentally on rats fed a stock laboratory diet.‘® The discrimination factor of 4 for
calcium against strontium from diet to bone in
manhas been reported by Schulert** and Bryant.**
A more appropriate value for the rats in this situa-
tion might be the OR,,,,,.-aie: =0.16 obtained by a
study of wild kangaroo rats living in the Nevada
desert.*°
The Sr®° body burdenis then
Sr°°/Ca levels in the various foods are shownin
(Sr**/Ca),=(Sr®*/Ga),(OR,_,)(OR,_,)
~ (8.4 10°)(0.7)(0.16) =924 puC Sr**/g Ca.
Table 31. This study was based on the analysis of
various food samples in what may be considered
an average diet. The data were obtained froma
study of the diets of 14 males on Rongelap.*’ It
was assumedthathalf 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. Thisis very close to the equilibrium
The value obtained in this manneris approximately twice the value 470 to 545 puC Sr°°/g Ca
obtained by direct radiochemica! analysis 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 discrimination ratios or perhaps lack of equilibrium
bet ween the Sr®°/Ca in the animals andin the
body burden (23 muC) estimated by Woodward
from the urinalysis data.*°
Another effort was made in the 1959 surveyto
gather samples of meals to be assayed for Sr°°/Ca
soil at 2 years. The latter possibility exists, since,
althoughthe 13 adult rats analyzed by Held“ at
4 years had values close to the 2-year level, 443-5
181 puSr°°/g Ca,the life span of the rat is only
content. However, since the Marshallese were
found to subsist to a large extent on foods notin-
a=? years.
digenousto the area, such as C rations, rice, and
Table 31
Estimate of Sr°° in Diet of Rongelap Adults, 1958
A
Meatfrom mature coconut
Meatfrom drinking coconut
Milk from green coconut
Pandanus, edible portion
Arrowroot
Breadfruit
Fish
Clams
Crabs, land
Total
B
AxXB
D
Daily
Ca
intake,mg
Fraction
of total
Caintake**
Sr°°
content,
puC/gCa
Contribution to
total daily
Sr* intake, uyyC/g Ca
89
75
116
79
58
0.075
0.14
0.15
0.15
2.10
6.7
10.5
17.4
11.9
121.8
0.008
0.013
0.022
0.015
0.152
1,200
‘210
1,000
930
19
9.6
2.7
22.0
14.0
2.9
449
0.56
45
139
45
14
0.60
0.13
4.00
4.00
660
a
Cc?
ae)
eo
*Based on average daily diet of 14 Rongelap males.*”
** Based on total calcium intake of 0.8 g/day.
eri
DXE
Ca
content,
mg/g
27.0
18.1
180.0
56.0
0.034
0.023
0.225
0.070
The diet also included imported foods: rice,
canned C rations, flour, tea, milk, salt, and sugar.
en
E
Daily
intake,* g
{wet wt)
260
280
5
(4,000)
8.8
6.4
1.1
(280.0)
67.5