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Summary oo
the Racwoioica.
Status
of
the Bikini Atoll!
Phiiip . Gustafson
Fullout Studies Branch
Diviston of Biology and Medicine
-
May 1968
,
A number of radiological surveys of Bikini Atoll have been made sinc:
iY4o.
The most recent survey was conducted in April and May 1967.
The
“son eriort was dovoted to the measurement of ambient radiation levers usit,
noveral
types of detectors.
The external radiation field was mappedin con-
eiderabie 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
yomma-ray spectrometry.
Representative samples of local plants and animals
wousch mepht be caten by the returning natives were collected and have been
analyzcd for radioactivity.
The results of the 1967 survey provide a basis for making reasonable
estimates of the total
(external plus internal) radiation exposure which
tue Bikinians might receive over the coming years,
atoll.
if they return to the
background radiation on the atoll is. duc almost exclusively to
cosmic radiation, and there are only trace amounts of the naturally occurrii
radioelements in the area.
Except in the immediate vicinily of nuclear
a Conations, the composition of the residual gamma-ray radioactivity was
vimilar throughout the atoll, consisting of about 70% 137¢s,
spy,
‘ye
20%, 90 Cy, and 10%
'o place;
Encu was
125.
b.
the
oa
;
-placc
Variations
in intensity
were observed from
least
contaminated,
followed by Bikini Island
itselt.
oo higasSt values in the heavily overgrown interior.
web Vad
-
SAR
bake
Mame
gf
.
Wanguo Cubbeoy,
ay,
wae
8,
8,
noes
—
A Jose «radient existed across Bikini, with lowest levels on the beach areas,
oan
atel
"bey
i?
oo
tag
ete
States.
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