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be given for such amcunts since thare are not only many oloments involved
in the fission product series but also the half-lives of the individual
elenents produced in fission extend from seconds to centurios. However,
as © practical consideration, the most effective group of fission product
elements, as military agents, are those whose half-lives range from several
This group of fission products will serve
wosks to the order of a year.
as. the basis for the values subsequently givon.
Nore precisely, it will
be for a mixture of fission products that exist in an irradieted natural
“mixture of uranium for a period of 100 days which is then allowed to cool
for a period of 60 days before removal of the fission products as @® group.
“As a result of tracer studies done at serkeley, and subsequent |
oxperiments including an investigation of radiation effects which wote
accomplished elsewhere on the Projeot, the following cursory picture has
been’compiled.
The inhalation of 10 millicuries of the wmeseparated fission}
product mixture described above is estimated to be a minimum lethal dose
for the average adult humen. It is presumed that lethal injury will arise
in the main through pulmonary damage rather than bone marrow destruction.
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The oral ingestion of at least 100 milliouries of such a mixture would be
required to produce lethal injury which in this case would arise primarily \
from bone marrow demage produced from the strontium and barium absorbed fron}
the digestive traot and subsequently deposited in the skeleton. An estimate:
of the amount of this fission product mixture required to produce extemal
gamma rey injury can best be expressed in the following manner; 1 ourie of
radium gemma ray equivalent per square meter spread over a large plain
erea will produce at a level of 1 oentimetor from the ground ~ 0.8 roetrens
per minite, LO centimeters from tho ground - 0.6 roentgons por minute, snd
100 centimeters from the ground ~ 0.4 roentgens por minute. Expressed in
jferms of roentgens por day, corresponding veluos are 115 roentgens, 86 roent~
gena, and 57 roentgens, respeotively. In estimating, these values, an average
genmna roy enorgy of 0.7 Mev was assumed end absorption in the air as wall
as self absorption in the soil have beon
ignored.
The corresponding |
amount of bate irradiation is very difficult to ostimate in view of the
variation produced by the different thiclmoess of articlos of olothing, ot
cetera,
In general, however, it is likely that the garma ray vffeots will
predominate ac the more destructive... Inasmuch as 100 r of ‘total body
radiation oan be oxpected to produce, in a: significant number of individuals,
seme degree of irreversible radiation damage, it would appear that a flux
of ganma rays at this intensity would render such an area essentially wmin-~-
habitable,
It should be kept in mind that tha values civen above for
fenma radiation represent a hypothetical situation inasmuch as distribution
will never bo uniform end there will-be other variations duo to the presence
of buildings, trees, and irregularities of terrain.
A detailed discussion
_of the amounts of material required to produce crop damare is presented
in the scoompanying report,
<A more precise evaluation of the quantitios
involved for tho storilization of agricultural lends must await the acoum‘lation of further scientific knowlecge in this field of investigation.
In addition to the oritical effact upon living plents following
the contamination of large areas, thore 4s a furthor consideration which
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