tetAE
about 100 yds. to 150 yds. southwest of the position of
LSM-60....
report and
Report,
Both
Figure
(which
Figures
C-2
and
27 of Enclosure
shows
the
C-3
increase
of
the
present
F of the Crossroads
after Baker day)
are comparable,
essential agreement.
The thickness
in
depth
of
water
however, and in
of the mud layer
(Figure C-2 and Figure C-3), of the other layers of
disturbed and redeposited sediment (Figure C-3), and
the increase in depth of water as measured last summer,
all show a symmetrical distribution, elongated to the
southwest.
The
radioactivity
of
the
bottom
material
in
the
target area is concentrated in the top (mud) layer of
re-deposited sediment.
Though the second and third
layers
show
some
radioactivity,
and
even
the
superficial layer of normal sediment outside the mud
area is weakly radioactive in many places, over 90% of
the
plutonium
and
fission
products
are
in
the mud.
Therefore, an attempt has been made to estimate the
volume
and
weight of this material.
Owing
to the
difficulty in penetrating the coarse Halimeda debris
with
the
coring
instrument,
and the
restrictions
imposed on the location of cores by sunken ships and by
diving operations from COUGLA (ASR-S), the distribution
and number of cores was
not ideal
for this
purpose. —
With the additional
information furnished by small
bottom samples, however,
a rough approximation
is
possible.
* Appendix Figure Numbers replace original report.
Shown
on
one
year
activities
Table
C-3
are
following
the
the
calculated
BAKER Test.
radioisotope
relative
If these calculated
data
represent the relative radioisotopic presence in the cored mud samples (see
Table C-4) taken from the BAKER test area one year following the test, then
one can. project the current level of specific activity in 1984 as shown in
Table C-3 based on
half-life calculations.
the
remain
radioisotopes
fixed
in
the
This
mud
assessment assumes
although
there
was
that
some
speculation by researchers during the resurvey that Sr90 and Cs!37 would be
leached out because of their solubility in sea water.
little
has
been
leached
(see
Appendix
diminished gradient.
000087
C-6
B);
however,
We believe that very
there
should
be
a