noting that many of these early terminations of fertilized egg cells
may represent e natural mechanism for removal of many abnormal conceptions.
Although purely speculative, this concept does support the
possibility that a large proportion of the artificially mutated genes
would be eliminated by nature before becoming a significant social
burden.
B.
Evaluation of the Human Hazard Due to Radioactive Fall-out:
Internal.
The external hazard due to fall-out radiation is essentially
confined to the local fall-out area.
The internal hazard, i.e., the
hazard created by internal deposition of various isotopes in humans,
exists both in the local fall-out area and world-wide.
Quantitative
aspects of fall-out and fractionation of critical elements suggest that
the hazards to be expected locally are very great compared to the
world-wide problem.
If it is assumed that local fall-out areas will be
large because of large numbers of bombs being dropped, then the local
area hazard is likely to be the critical consideration for internal as
well as external radiation injury.
.
Criteria for Assessment of Biological Significance.
All of
the radicactive components of fall-out material are hazardous to some
extent.
It is not necessary, however, to evaluate in detail the radia-
tion injury due to each of these components.
In a general assessment
of internal hazard it is sufficient to find the component or components
which are responsible for the major part of the hazard.
From the point
of view of safety, the most critical element becomes the limiting
factor and any standards set for the critical element automatically
remove the others from need for consideration.
In estimating effects above the safety level, it becomes
necessary to add all elements which are of appreciable significance
in their contribution to the total effect.
As will be shown below,
Strontium-90 appears to be not only the critical element for determining safety standards, but it is also responsible for practically all
of the long-term effect, and therefore the parameters relating to this
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