48
at HASL
NRDL
No.
Samriine
Location
ConLecrion
Dats
Name
AGE}
2-11-56..----
»
IBRSo SawmeaveraboansSonna
HASL
No.
RETURN OF RONGELAPESE
RADIOACTIVE CONTAMINATION OF AREAS IN THE PACIFIC OCEAN FROM NUCLEAR TESTS
Table 47—NRDL Marshall Island Resurvey—1956 Results of Analyses of Human Urine Performed
Control. .._.) $-26-56_.....
do.
do.
do.
do.
Sune 1956.
TOTAL
Volume
RecEIVED
(mil)
190
250}
570
440
135
180
285
310
340
620]
200
360]
160
225
235
410
600
190
920
980]
900]
1,000
930
0
Pooled
sample
col- nee ae!
Jected at HASL,
do.
June 1956...
do.
Tune 1956.
do.
Tune1956.
do.
1,000
5, 000
5, 000
5, 000
C-DaTE
‘Total
AcTIviTy
3-25-56
3-25-56
3-25-56
3-25-56
3-25-56
3-25-56
3 25-56
3-25-56
3-25-56
3-25-56]
3-25-56
3-25-56]
3-25-56
3-25-56
325-56
3-25-56
3-25-56
3-25-56
3-25-56
3-25-58
3-25-56
325-56
3-25-56
3-25-56
TOTAL AcTivITY
dm
oe
*
48002240
3600-280
3360-4320
33204300
76001240
4400-280
82003360
220002.320
3480-240
76004320
4400+:320
4400-320
48004:320
4000-240
4800-4320
9800-360
2920-280
88004320
9200-4360
26004240
2400240
12604200
2200240
1360-280
42504250
Srv
dim/l
Catt
djmjt
o
according to the external gamma dose rate and
the amount of strontium-90.
1. Exrernat Gamma Doss Rares on
Rongear ATOLL
The external gamma dose rates at three feet
above the ground on the Island of Rongelap
are shown in Graph J. It would be expected
3. 440.3
THAIS
6 81.4
25404-63
5. 3kO 3]
148723
|.4.730.7
28624245
f2. 4.0.2
3348
170::100
S100
600-100
S100
S100
S100
that this curve would flatten out with time
due to the dominance of the cesium-137 with
its half-life of 27 ycars. The latest survey of
the Rongelap Island at the end of July 1956
showed a range of values from 0.2-0.5 milli-
roentgen per hour, with an average of 0.4
mr/br. However, the graph suggests an anticipated dose rate at the July 1956 survey of
**Carbonate precipitation.
2048
tion rather than the results of body elimination
of previously deposited Sr®.
B. Medical Surveillance
When the Rongelapese were returned to their
homeisland,it was planned to inaugurate a pro-
gram of continuing medical inspections. The
Rongelapese would be examined once # month
by a Marshallese practitioner and complete medica] examination performed once a year by an
American physician.
Arrangements would be
made for urine collections and analyses every
three months for the first year and afterward
on a yearly basis unless the findings indicate
Rongelap. The Rongelapese go on fishing expeditions to otherislands, including those showing both higher and lower activity. However,
these Rongelapese spend an appreciable part of
their time in boats over water where the external
gamma activity is near background values.
Thus, the yearly average for these probably
would not differ greatly from those on Rongelap Island.
2. Srrontrum-90
a. Food Supply
material, the decay should be more rapid so
the Rongelapese are contained in Table 48.
There are wide variances in the data so that
estimated average values are used. This is not
an unreasonable approach since it would be
expected that the food actually consumed would
be about as variable as the individual samples
collected for analysis. As will be seen below,
Since this was relatively fresh radioactive
that the dose rates on Rongelap Island at the
time of repatriation should be less than 30
milliroentgens/week.
The maximum permissible external gamma
1440.2
L920 2
1,040.2
exposure to adult workers recommended by
the National (U. 8.) Committee on Radiation
***Rongelap natives.
an environment of continual intake and excre-
rates now are the same as measured in the first
part of March 1954; i. e., the highest activity
on anyisland is about a factor of 12 higher than
undoubtedly due to the small additional fallout
that occurred during Operation Redwing.
Protection is 0.3 rems/week with an added
“Direct plating.
from internally deposited cesium-137.* The
gammadose rates on other island of Rongelap
Atoll have not been followed as closely as on
Rongelap but the data suggest the relative dose
about 0.1 mrf/hr. The higher value found is
1.60.4
the necessity for more frequent analyses.
A
radio would be provided on Rongelap for communication with the Trust Territories Office on
Ebeye (Kwajalein Atoll) where a plane would
be available at all times for any emergency.
A fully equipped dispensary would be provided
on Rongelap and an experienced health aide
(a Marshallese) would be present at all times.
Before their return, the Marshallese would be
given a complete medical examination, and
immunized against smallpox, typhoid and
tetanus.
C. Environmental Contamination
The degree of contamination on the home
islands of the Rongelapese was considered
49
restriction that the maximum permissible
accumulated dose in rems, at any age is equal
to five times the number of years beyond age
18, provided no annual increment exceeds 15
rem. (This applies to all critical organs except
the skin, for which the value is double.)
The
maximum permissible exposure for the population as a whole from all sources of radiation,
including medical and other man-madesources,
and background shall not exceed 14 million
rem per million of population over the period
from conception up to age 30, and one-third that
amountin each decade thereafter.
It is difficult to extrapolate precisely far into
the future, but the data suggest that the gamma
doses on Rongelap Island would not. greatly
exceed (if at all) 0.5 roentgens for the first year
of reoccupancy, with lesser doses in subsequent
years, plus some additional whole body dose
The basic data on the normal food supply of
these estimates could be in error by a factor of
several without changing the conclusion,
The isotope of principal concern in the food
chain is strontium-90.
For an adult worker
the maintained maximum permissible body burden is 1,000 Sunshine Units (1,000 micromicrocuries of Sr® per gram of calcium). Values for
maximum permissible exposures to the general
population are 1/10 that for adult workers, or
100 Sunshine Units, maintained level in the
body. The National (U. 8.) Academy of
Sciences report stated, ‘‘.
. There seems no
reason to hesitate to allow a universal human
strontium—burden of 1/10 of the permissible
.
. .” for adult workers.
to the 100 Sunshine Units.
This corresponds
*Gamma dose rates at three feet above the ground .on the Island of
Rongelap in June 1957 were asfollows:
Highest reading 0.13 mr/hr
Lowest reading 0.01 mrfht
Average reading 0.03 mr/hr