approximately 500 8 700 miles, the falj-out density of fission pro-
ducts and plutonium wofild be 7.2 x 10°°
grams per square mile per bomb,
Assuming that 200 persons are supported per square mile of arable land,
the stroptium0 and yttium” ingested per person would be less than
8 x 107°”
gram per person per crop" in the local (350,00 square mile)
contamination area and the amount of plutonium, while contributory,
would be relatively unimportant.
9
6{
If we assume the integrated lethal dose of strontium’?
plus yttium 0 to be 40 microgram years, which may be in error by a
factor of 4, the number of bombs detonated per local area of 350,00 square
miles fo reach the,lethal threshold in that settling area would be between
1 x 10° and 2 x 10°, assuming that the uptake occurred in one crop only.
On the othér hand, if the crop uptake is asaumed to be continuing and
activity decaying exponentially with the natural half-life of strontinn20
and a continuing human consumption, the numbers would be between 3 x 10°
and 40 bombs.
These figures are based on exposure during a life span of
47 years. If one considers a 200<-day period for exnosure, the figures
become between 3 x 108 and 4 x 10% bombs in the case of a single crop and
4 x 10% and 600 in the case of continuing uptake by crop plants.
7, <All these figures must be interpreted with the warning
that we do not fully understand strontium metabolism in man and that
factors of absorption and excretion may eventually have to be altered.
Conclusion: If one assumes this limited area and single crop
contamination, it is obvious that a determined people aware of the danger
could either migrate or obtain food from other sources.
(B) Hazard from inhaled particulate matter.
1.
There is little question but what there is real danger
2.
Assuming plutonium particles 2 micra in diameter are
to inhaling particulate radioactive matter in such finely divided particles
as to be retained within the lung. COlear-cut data on this are not yet
available and await evaluation of experiments initiated sometime ago in
connection with tha nile particle problem.
inhaled, the small mass of tissue irradiated would receive 390 roentgen
equivalents physical per day or 78CO roentgens biologic eguivalents per
day. This amount of radiation would be sufficient to cause significant
damage to the lung tissue immediately adjacent (involving un to 100 cells)
and quite possibly to cause carcinogenic change.
3. In the case of beta radiation from fission products,
the dose from such a narticle integrated un to 7 days would be 72 roentgen
* For example, 1 harvest of corn, wheat, or other staple.
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