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The chief edventage of following milk as a monitoring device
is thet it yields en immediate estimate of the emount of Sr-90 which
man Will ingest.
This is more direct end more relieble than at-
tempting to predict the moven@mt of Sr-90 to man from analyses of
fallout or of soil.
Bone
Analyses of humen bone efford a direct measure of the Sr-90
level et a given time.
However, as previously mentioned, humen bone
is not yet in equilibrium with the Sr-90 of the environment.
Thus,
‘measurements made et the present time ere only of value when viewed
in reletion to other materials, particularly human food and the
present end predicted levels of Sr-90 on the earth's surfece.
Human bone semples show the lowest levels of Sr-90 of any
biological material being enalyzed.
This means that a large sample
of bone is required for anelysis and such specimens
reedily obteinable.
are not always
The extensive progrem at the Lamont Geological
Observatory has yielded severel humdred autopsy specimens from all
over the world.
Dr. Kulp, who is in charge of this work at
Lemont, will report on this work in deteil.
The enalysis of bone requires the separation of Sr-90 from
lerge quantities of calcium but only negligible emnomts of other
redioisotopes are present.
The current levels require not only low
background counting equipment but the most extreme care in the
prevention of contemination of samples with other redioactive
materials.
Doeax
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