Part
of
transpired
the
by
island
plants.
rainfall
Essentially
fraction of the rain infiltrates
groundwater table.
evaporates
no
the
soil
is
taken
is
lost
by
up
and
partially
surface
runoff.
column and eventually reaches
On many of
the
larger
islands
a
the groundwater is fresh enough for human consumption,
determined
effort
to
ensure
containment systems above ground,
storage
capacity
drinking water.
to
the
may
and at some
be
a
year-round
supply
of
There has
rain
water
in
but when unanticipated droughts occur,
exhausted
and
groundwater
must
be
relied
the
on
for
Any radionuclides that have migrated through the soil column
groundwater
individuals
the
the upper
atolls this water is used for household purposes and garden crops.
been
A
The surface of the water table in the Marshall Islands is
between 2.5 and 4 m below ground.
layer of
water
or
will
contribute
it.
Therefore,
consuming
some
an
internal
evaluation
radiological
of
dose
to
the ‘significance
of
radionuclides detected in both the cistern water and groundwater was necessary
to meet the survey objectives.
There were 55- to 100-1 samples collected for analysis from cisterns and
well pits.
filtered
were
Unfiltered water was collected from the cisterns; groundwater was
through
returned
processing.
239+240
Pu,
salinity.
1l- and 0.45-p filters
to
One
and
the
Lawrence
separation
241
from
Standardized
samples.
The
procedures. 9,10
remainder,
A
with
fraction
prepared
Livermore
technique
all
used
of
solutions
were
of
National
was
samples
carrier
radionuclides
to remove particulates.
standards,
samples
isolate
water
was
duplicates,
to
purified
analyzed
and
blanks
samples
(LLNL)
906,
regardless
added
radiochemically
the
Laboratory
to
were
All
>
water
acidified
using
at
13765
of
the
for
published
LLNL
were
and
sent
the
to
a
contractor laboratory.
Radionuclide
concentrations
since 1975 are “hown in Table 2.
in
cistern
water
sampled
at
Bikini
Atoll
Table 3 lists concentrations in cisterns and
other fresh water supplies at other Northern Marshall Islands Atolls.
The
Likiep,
concentration of
Ailuk,
concentrations
Mejit,
radionuclides
Wotho,
in groundwater
and Ujelang are
at
Rongelap,
shown in Table 4.
Groundwater
at Bikini and Enewetak have been previously discussed
more recent results from these atolls will appear in future reports.
Utirik,
3,11
and