even roughly in view of the variations of conditions under which nuclear
explosion tests were conducted and in view of the long period of natural
weathering since that time.
Some laboratory measuranents exist fer
leaching of cesium from wedron sand, which of course is not the same
as coral.: For thermal treatment at 1200°c, which is certainly encountered
in fireballs and clouds from nuclear tests, the time for leaching to
halve the cesium is initially about four years; for treatment at 20°C
it is about two years (Lane, 1970).
After the 15 years at weathering
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at Eniwetok Atoll, certainly the easily leached radionuclides have
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much higher than the few years observed in these laboratory experiare
ments. Thus, leaching and weathering / not very likely to significantly
ene
been removed, and so the time for halving by leaching is probably
hasten the decay of radioactivity beyond the nuclear decay times.
En
Wowever, weathering processes are known to he complex and to depend
upon many variables (Crocker, 1965).
Distribution of Fallout in Water
The distribution of radioactive contamination in the sea after
Distri-
bution is altered to a much lower extent by the movement of organisms
ra,
distances by oceanographic effects and in depth by gravity.
sor
having been deposited by fallout is largely determined in horizontal
dispersion are surface winds, currents, and horizontal density gradients.
ore
12
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primarily by ocean currents, although other factors in the horizontal
AN ER Oe ee 8, a oe
The horizontal, or geographical, spreading is probably determined
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in and out of che contaminated area (Lowman, 1960).
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