Wiile there has been little investigation of specific defense measures
which might be feasible, it appears reasonable to assume that the hazards
from any one aspect of radioactive fallout could be greatly reduced by
appropriate defensive action.
Strontium” is still considered to be the
most probable critical factor.
Dr. Western brought out that there are many unanswered questions related
0
to hazards from strontium’ -
.
He said that the distribution of strontium”
in local fallout and the stratosphere are poorly known.
Also poorly known
are the actual concentrations of strontium 90 in the human skeleton necessary
to produce various biclogical effects.
A program to obtain better biological
data in large mammals, using dozs, is being initiated.
The Sunshine program of assaying the occurrence of strontium” in the
biosphere has progressed sufficiently to permit a semi-quantitative
estimate of the ratio between the fal’out of strontium” and the occurrence of strontium?” in the skeletons of persons living in areas of general
fallout.
This ratio is based on direct observation of concentrations in
soil and bone samples in a particular geographical area, and might vary
considerably with varzvation in such conditions as dietary habits, soil
characteristics, desiyn and use of weapons, and protective measures.
Dr. Western states further that the highest percentages of strontium
observed in human bones in the United States are of the order of one=
thousandth the maximum permissible value for occupational exposure to
strontium”” 90 currently recommended by the International Commission on
radiological Protection and by the United States National Committee on
Radiation Protection.
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