- §—
difference ‘between one altitude and another is equal in effect, other effects being equal, to a certain number of Sunshine Units in bone. Now to follow this thought thr wugh, 1
Sunshine Unit is equal to 3 milliroentgens per year.
Therefore, the difference in annual cosmic ray radiation cosage
between Washington, D. C., or any place at sea level in this
latitude, and Denver, Colorado, is equal to 8 Sunshine Units,
that is, 16 times the present body burden of equilibrium bone
or bone near equilibrium as we see it in young children who
are growing now.
.
Therefore, we must examine whether anything in our
experience indicates that these differences are significant
in terms of the occurrence of the principal effects expected
of radiostrontium, namely leukemia and bone cancer. Wow of
course when one looks for such vital statistics, one finds
that they are very hard to acquire.
However, the National
Institutes of Health and the Department’ of Health, Education
and Welfare, have given us statistics for the occurrence of
leukemia and bone cancer for the year 1947 for the three
cities, New Orleans, San Francisco and Denver. They are
shown in Table I.
TABLE I
Occurrence of Bone Cancer and Leukemia
(New Cases per Year per 100,000 Population)
Bone Cancer
Denver
New Orleans
Leukemia
2.4
208
San Francisco
6.4
6.9
2.9
10.3
It is clear from this table there is no obvious effect of
altitude, and it is aiso clear that there are other factors
which are noticeably more important than cosmic ray cosage.
Of course there may still be a considerable effect of alti-
tude hidden in large fluctuations caused by other factors,
which presumably are largely unknown and we cannot say that
this proves anything.
It does, however, give us some assur-~
ance from normal experience that the effect of eight Sunshine
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