Appendix II
Enewetak Radiological Survey Report
Summary of Findings Chapter
W. Nervik, Lawrence Livermore Labcratory, Livermore, California
CURRENT RADIOLOGICAL CONDITION
OF THE ATOLL
INTRODUCTION
External Gamma Radiation Levels
It has been the purpose of this survey
Three independent techniques were
to gain a sufficient understanding of the
total radiological environment of Enewetak
used to measure external gamma radia-
Atoll to permit judgments as to whether
tion levels on the Atoll:
or not all or any part of the Atoll can
e
LiF and CaFo thermoluminescent
safely be reinhabited and, if so, what
dosimeters (TLDs) were exposed
preliminary steps toward cleanup should
for 33 months on seven of the
be taken and what post-rehabilitation con-
northern islands.
straints must be imposed,
e
Enewetak Atoll has an extremely
- Atomic survey instrument was
broad range of radiological conditions in
a small land mass.
made at each soil-sampling loca-
To gain an under-~
tion on each island.
standing of the details of this range of
@
conditions, it has been necessary to obtain
An aerial survey with Nal detectors
-
=
WAD
and analyze a very large number of sam-
a eee he eee
maw nee
Verbs Yves
thn
bAte
awtionn
Vsewne ~
surface area of every island.
ples from all components of the environment,
A measurement using a Baird-
All three techniques yield results
To gain an equivalent understand-
ing of the implications of this range of
which agree to within about 10%.
137
conditions for rehabilitation of the
and
8065
Cs contribute most of the total
Enewetak people, it has been necessary
external gamma radiation, with the
to postulate population distributions, life
remainder due to small amounts of other
fraught with uncertainties under the best
125
155
Sb,
Eu,
gamma emitters such as
and 241
Am. The amount of 60 Co rela-
of circumstances, but particularly so for
tive to 13766 varies throughout the Atoll,
the current, rapidly changing Marshallese
with a range of values from about 0,5 on
culture.
JANET to greater than 14 on JAMES.
styles, and dietary habits — an endeavor
This section is a summary of the data
Average values for each isotope on each
obtained from the Survey, the postulates
island are given in Table 214,
used, and the population dose assessments
erence, a map of the Atoll is shown in
derived from data plus postulates.
Fig. 146,
The
For ref-
Southern islands (SAM to KEITH) are
reader is cautioned against expecting or
using a ''simple' description of the radio-
characterized by low and more or less
logical condition of Enewetak Atoll, be-
uniformly distributed gamma-radiation
cause no single value of any component of
levels over the area cf each island.
the radiological condition is applicable to
exposure levels increase,
the entire Atoll without being misleading.
ients become severe, with beaches
II-1
As
exposure grad-