“q
teeTe Le
The
ships
themselves
do
not
pose
a_
significant
radiation hazard, although the activity of the sediment in the immediate
vicinity of some may be as high as 20 pCi/g (Appendix C).
accumulating on the ships and a piece of one of the ships
The sediment
itself will
be
reported on in Appendix B,
Of
leaking fuel
26
sunken
more
concern
is
conventional
tanks or from exploding ammunition.
Japanese
ships
still
rest on
the
contamination
from
However, at Truk Lagoon
bottom of a
busy harbor and
apparently are not dangerous if left undisturbed (Appendix C).
The vessels
are being covered with increasing amounts of sediment and coral and are the
site of active marine life.
Moderate chronic
fuel
without
difficulty
by
ecosystems
owing
However,
the
site
Bikini
such
should
be
(10)
examined
by
leakage can
to
divers
be
borne
biodegradation.
to
ascertain
the
current state of the sunken ships.
The third
important event was
the Bravo
creating the sizeable crater in the lagoon off Nam Island
shot
in 1954,
(Figure 2) which
now might be used to store very low-level radioactive materials.
2.1.2
Water.
especially after the
Bravo
Although the levels of contamination were high
shot,
by 1972
water was Tow enough to meet the Federal
the specific-activity of lagoon
standard for fresh drinking water
(11 N).
2.1.3
(0-4 cm depth)
limits.
Sediment.
The specific-activity of the lagoon sediment
is higher than lagoon water but still
permissible
Cesium-137 activity is generally below 10 pCi/g (Figure 2), and on
the lagoon bottom within 15 km of Eneu and Bikini
(12).
within
The
levels
of other
radionuclides
in
Islands it is 0.1-1 pli/g
the
Bikini-Eneu
area
are:
cobalt-60, 13 plutonium, 5; americium-241, <5 pCi/g.
Analyses of sediment
from the
northeast
corner of the
lagoon down to depths of 60 cm have shown that radionuclide levels fall off
5000011
18