on every island, but emphasis was given
kind of data obtained for each of the pre-
to — and proportionately larger numbers
dominant isotopes on each of the islands,
of samples taken on — those islands which
905. values for 0-15 cm core samples on
were known to have been sites for nuclear
JANETare plotted in Fig. 147.
testing activity or to have been subjected
Table 215 presents geometric mean
to large amounts of fallout from such
values and ranges for the four predominant
activity.
radionuclides on islands from ALICE
Two types of soil samples were taken
through WILMA.
On islands where there
on each island: "surface' ‘ and "profile."
are significant differences in activity
At "surface'' sampling locations, two
levels between densely and sparsely
samples were taken — one a 30-cm” xX 15-
vegetated areas, data for both are given.
cm-deep core, and the second a composite
Similar data for groups of southern islands
of two 30-cm” x 5-cm-deep cores,
are shown in Table 216.
At
"profile'' sampling’locations, 100-cm?
"Profile" samples showed a wide range
samples were taken from the side wall
of activity distributions as a function of
of a trench dug for the purpose. Nominal
depth on different parts of the Atoll,
depth increments for the profile samples
amples of the types found are given in
were 0 to 2, 2to 5, 5to10, 10 to 15, 15
Figs. 148-151.
to 25, and 25 to 35 cm, and at 10-cm
in this area are not very meaningful,
increments to total depth.
Fig. 148 shows the profile distribution
Total depth
Ex-
Although generalizations
for profile samples varied from 35 to
normally found on the southern islands,
185 cm, depending on the distribution ex-
Here the activity levels are usually low
pected from the testing history of the
through the full range of depths sampled.
island being sampled,
Some sampling locations show concentra-
In general, the predominant Species
tions decreasing somewhat from the sur-
found in the soil samples are 905, 137 og,
239 pu, and 8065, 404 3 e, 10ley
face through the first 10 or 20 em of soil,
102mpy 1256) 1335, 1346, 1525,
1945, 1555,
u,
207
Bi,
2266p, 235,
Figure 149 shows the type of distribution
often found inland on islands subjected
to fallout but not to construction or other
2385u and 241 am are also present in
ground-zero earthmoving activities — i.e.,
some or all of the samples.
a rapid and fairly steady decrease of
As was the
case for external gamma levels, small
activity levels from the surface to total
amounts of radioactive species on the
depth,
southern islands (SAM to KEITH) are
found on beaches and exposed areas on
distributed more or less uniformly over
these same islands — i.e., uniform or
the entire land area.
slowly decreasing activity levels from
On islands where
Figure 150 shows the distribution
larger amounts of activity are present,
the surface to total depth.
the highest levels of all species are found
shows a distribution pattern found occasion-
at the island centers or in proximity to
ally on islands which have been the sites
ground-zero sites, usually related ina
for tests or have been subjected to con-
direct way to the vegetation density in the
struction and earthmoving activities
immediate area.
(primarily IRENE, JANET, PEARL,
As an example of the
Figure 151