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Discussion of Findings
We have seen that many kinds of samples are being collected
routinely from a large number of locations, and that the Sr-90
in these samples serves as a tracer for the study of many
physical, chemical and biological processes.
In this discussion,
an effort will be made to simplify the analyses of the data and
to deal only with those portions of the overall Sunshine program
that are concerned with an estimate of the human hazard from
Sr~90.
The fiumdamental questions which must be answered are these:
1.
How much Sr-90 has been deposited on the
earth's surface?
2.
How much Sr-90 from detonations to date
remains suspended in the upper atmosphere
and how long will it teke tp precipitate?
3.
How much Sr-90 will human skeletons contain
when they are in equilibrium with the ex-
pected levels of Sr-90 in soil?
Deposition of Sr-90 in Farth
As noted earlier there are two basic procedures by which the
wide spread deposition of Sr-90 can be documented.
The first, end
the most direct, is by the collection of soil samples end their
analysis for Sr-90.
The soil analyses for the yeer 1956 are plotted in
Figures 1 and 2, which gives the estimates of Sr-90 deposition in
millicuries per square mile.
Similer dete has been obteined on
the basis of semples collected from the gummed film network.
These data are sumerized in Figures 3 and 4 which give the estimated
cumulative Sr-90 distritutions as of July 1, 1956.
In recent
POE arcuiygs
GT