APPENDIX V
Srief Summary of the Radiological Status of the Bikini Atol.
Philip F. Gustafson
Fallout Studies Branch
Division of Biology and Medicine
May 1968
A number of radiological surveys of Bikini Atoll have been made since
1°46.
The most recent survey was conducted in April and May 1967.
The
main effort was devoted to the measurement of ambient radiation levels using
several
types of detectors.
The external radiation field was mapped in con-
siderable detail on Bikini and Eneu Islands, and less thoroughly on the
remainder of the atoll.
The various radionuclides and their concentrations
which gave rise to the observed radiation Field were determined from field
gamma-ray spectrometry.
Representative samples of local plants and animals
which might be caten by the returning natives were collected and have been
analyzed for radioactivity.
The results of the 1967 suvvey provide a basis for making reasonable
estimates of the
total
(external plus
internal)
radiation exposure which
the Bikinians might receive over the coming years,
atoll.
Background radiation on the atoll is due almost cxclusively to
cosmic
radiation,
radioclements
detonations,
and there are only trace amounts
in the area.
the
Except
207
OO.
Co,
and
of the naturally occurring
in the immediate vicinity of nuclear
composition of the residual gamma-ray radioactivity was
similar throughout the atoll,
nae
if they return to the
10%
to place; Eneu was
2d
Sb.
the
consisting of about 70% 137¢5,
,
Variations
least
contaminated,
A dose gradient existed across Bikini,
and highest values
.
—
in intensity were observed
with
followed by Bikini
lowest
Island itself.
levels on the
in the heavily overgrown interior.
from place
beach areas,