34
where variable levels of activity with depth would mask any
diurnal-nocturnal variation that might exist.
The change of relative radioactivity of the water with
derth is variable but appears to fall into regional patterns.
It 1s likely that at the time of the Marsh survey those regions
containing the highest relative activity levels in the deeper
layers were regions primarily affected by fallout, while those
regions having the bulk of the radioactive materials in the surface layer were regions to which the radioactive materials in
solution had been carried by surface currents.
It would follow
that by the time of the survey vertical mixing had not taken an a
{mportant part in redistribution of the radioactive materials;
.
possidle exceptions may occur in the immediate vicinity of the
Mershall and Martanas Islands.
This
interpretation which is based on the assumption that
most of the radioactive material went into either a true solution or & suspension of very small colloidal particles soon
after fallout is supported by the fact that most of the activi-
ty passes through 4 Millipore filter (Table 3).
ferences
However, dif-
in specific gravity of the particles would result in
the same type of distribution.
It is possible that relatively
higher values near the surface for stations to the westward are
accounted for, in part, by fallout of lower specific gravity DOE ARCHIVES
than that of fallout nearer the test site.
The particles of
lower specific gravity would be assumed to have gone into complete solution while still near the surface.
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