radionuclide concentration from the surface to each soil
depth.
This tabular
listing of the data shows the decline in activity as a function of depth in
the soil column.
The ratio between radionuclides is not the same for all
islands; this reflects the difference in device design, and consequently the
mix of radionuclides in tests conducted around the atoll at or near the
Various islands.
More data for the radionuclide concentrations in the soil
Profiles are given in Appendix C (Tables C-1 to C-104); included are the mean
and median of all
profile increments on each island as given in Tables 5 to
30, the maximum and minimum values, the standard deviation, the mean of the
logarithms,
and
the standard
deviation
of the logarithms for each of the
In
Profile increments for all the profiles collected on each island.
addition, the same types of data are listed for each of the six regions on
Bikini and Eneu Islands that are used to calculate the distributed mean. The
radionuclide concentration data for each individual soil profile on each
island are given in Appendix D (Tables D-1 to D-56).
The median, mean, and distributed-mean concentration with depth in the
Soil column for all soil profiles for '37cs, 90sr, 239+240py, and 24]Am is
Shown graphically in Figs. 11 to 16 for Bikini and Eneu Islands.
The decline
in activity with depth is generally exponential at Bikini Island, although the
90s7 activity declines less rapidly with depth than do the other three
nuclides. The '37cs on Eneu Island also declines exponentially; however, the
90Sr, 239+240py, and 24am appear to be more constant to a depth of about
40 cm. The activity levels decline more rapidly between 40 and 60 cm, but are
So Tow at 60 cm that a great deal of uncertainty is introduced, especially
when only a few samples are available.
The distribution of 905r, 239+240py, and 24]Am on Eneu Island indicates
that the surface soil may have been mixed to a depth of about 40 cm at some
point in its past history.
the test Program.
The island was the main residence island during
Many tent camps, clubs, pads, storage sites, and other
facilities were constructed on the island and could have produced conditions
leading to such results.
RADIONUCLIDES IN VEGETATION
In
Table
31
are
listed
the average
concentrations
of
137¢s,
90sr,
230+240py ang 241 Am in vegetation samples collected at Bikini Atoll.
ae
do
33