varies with
deration.
the
nuclide
Thus,
under
concentration ratios to predict
consi-
nuclide concentrations in fruit from
we also describe
the use of concentration Factors and
those observed in soil or leaves.
Introduction
Since the
The longer-lived fission and
termination of nuclear
testing on Bikini Atoll in 1958,
activation products are the nuclides
periodic environmental surveys have
of primary concern at Bikini Atoll.
been conducted
Previous studies have shown that
to evaluate the radio-
early surveys of Bikini Atoll as well
because of their long half-lives and
4
137
90
Cs, an
Sr,
large inventories,
as
239,240, | contribute nearly all the
logical status of
the atoll.
The
the recent survey and assessment at
nearby Enewetak Atoll indicate
population dose from the terrestrial
that
+
In this study, our major
concentrations of radionuclides in
pathway.
certain terrestrial foods are rela-
emphasis is on 0c
tively high,
suggesting that
239,240,
the
Pu.
terrestrial
However,
los and
«
the results ob-
for 065 and 2 vam are also
foodchain could be a major
1-4
exposure pathway.
in June 1975,
included because
Bikint Atoll was
e
tributed and is present in the marin
resurveyed
to deter-
tained
ere is widely dis-
the
pathway and because the concentration
terrestrial environments of Bikini and
of 241 Ay is still increasing slightly
241
mine
Eneu
the residual
Islands,
the
the atoll (Pig.
radioactivity in
two main
lL).
islands of
Pu.
due to the decay of
In this report, we describe the
The 1975 survey
the soil and vegetation
included measurement of environmental
results of
gamma-ray exposure rates and
studies of the 1975 survey.
the col-
discuss the use of the data to derive
lection and analysis of samples of
soil,
ground water,
cistern water,
We also
and
relationships that predict the plant
vegetation for use in assessing the
uptake of nuclides from soil on
internal dose via various ingestion
Bikini Atoll.
60
90
Sr,
of
Co
pathways.
(The dose from external
gamma exposure and
the radionuclide
i
Geometric mean values
137A, 239,240,
24).
.
surface-soil
Am
u,
“
?
.
concentrations
concentrations in cistern and ground
developed for Eneu Island and for
water have been previously
each
c
reported.??°)
of
Xikini
the
four areas
Island was
and
are
into which
divided.
‘We alse