-27-
UCRL-3644
No gross evidence of osteogenic sarcomas has been observed following administration of P?2 (approximately 100 rep to bones) to polycythemia
vera patients.
However, these patients do have a high incidence of leukemia.
This leukemia tendency is probably attributable to both the radiation exposure
and the nature of the basic disease of the blood-forming system in these patients.
Special phases of the Sr?9 problem need additional examination:
(a) In several areas of the world, Sr? concentration exceeds the
average world values by more than a factor of 10.4,9 This excess poses
questions as to the origin of the enhanced concentration. To a reasonable
extent, it is explained by Libby as calcium deficiency of soils in such areas.
Rainfall variation also leads to variation in fallout. It will be useful to know
more about these anomalous effects. Current world-wide sampling is perhaps
far from representative of the world as a whole, because special effort was
made to seek out low-calcium high-rainfall areas.
(b) There maybe a factor-of-8 difference between sr?9/Ca concen-
trations in soil and in humans, resulting from discrimination in favor of
calcium (Libby); this must be further studied.
(c) Some factor of uncertainty must be allowed for in the prediction
of levels today and in the early future of Sr?9 in humans, considering that
the most recent of these measures are based on early 1956. These uncertainties may amount to a factor of somewhat more than 10.
os
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(ay *nengusn it ishel Yetethetotal uncertamtymnthe estimated
human burden of Sr’”
throughout the world could mean an upper limit of
10 x 8 x 10’x Libby's lower estimate of exposure in the near future, 0.02 r/yr,
/ which works out to about 15 r/yr or 4 MPC.
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This possibility indicates that
the Sr?9 fallout problem urgently calls for further attention.
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The Cs!" problem is quantitatively similar to that of Sr?9.
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These
two fission products are present in the air and in fallout in approximately
equivalent quantities, > and they have similar decay rates. Whereas strontium
is a bone-seeker, cesium is found in approximately equal quantities throughout the body, though less in bone than in soft tissues. Its distribution roughly
approximates that of potassium.
Furthermore, cesium is not retained by the
body. Thus, the cesium burden at any given time rapidly reaches equilibrium
with the rate of fallout, in the potassium pool in plants and animals.
Marley, in the British report, 4 writes (page 124), ''The highest bodyactivity detected so far in the United States is found to be 4x 10-3 pC. This
activity if maintained would produce a total body irradiation of 0.0006 r per
year or about 1/30 of the dose due to naturally occurring potassium-40 in the
body.''
Since this time in early 1956, the failout level and fallout rate of sr90
have been increased only slightly, so that we may assume that the Cs}37 level
in man, which is more reflective of immediate fallout, may have risen by as