.
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-17-
cesium and strontium, when introduced into the sea from fallout,
would be present most likely in the insoluble or par-
ticulate
state.
evidence (8, 20) and
Indirect
observations (9) support this view.
pased on geochemical studies
direct
The indirect evidence is
in which the potential supplies
of the elements to the seas from weathering of igneous rocks
are compared with the
solution in the sea.
to fallout
amounts of the
elements present
in
These values cannot be applied directly
analyses but
they do provide
the basis
for an
estimate of the fraction of a given fallout element that would
remain in solution in the sea.
The levels in
the sea (ppm) of the
naturally occurring
forms of those elements reported in the present work are shown
in Table 3.
ring elements
ments
Also listed are the forms of the naturally occurin sea water,
the percentage of the fallout ele-
in solution according to direct and indirect evidence,
the principal chemical state of the fallout in sea water, and
in
the average percentages of the fallout elements observed
plankton samples collected about three months after fallout.
Of the radioactive fallout elements shown, only two, cesium
and strontium, would occur normally in soluble form in the sea.
The radioisotopes of these elements were found in the least
amount in plankton.
In contrast,
the radioactive fission-
products with the lowest solubilities, Zr95 and Cel44,
were
present in plankton in the greatest amount (20.2, 8.6 per cent)