Part Vill
Dor 4
Biology and Medicine
PROJECT SUNSHINEggg
To disseminate the most up-to-date knowledge of fallout and radiation effects, Commissioner Libby presented a review and analysis of available data in a speech delivered on
March 27 before the Swiss Academy of Medical Sciences Symposium on Radioactive Fallout.*
Monitoring and sampling programsto study the distribution of radioactive fallout continued during the January-March quarter, as did research on the biological hazards of fallout. The results of analysis of some of the samples collected are given below.
Stratospheric Monitoring
The preliminary results of analysis for strontium 90 of some of the stratospheric samples collected during the period November 1956 through November 1957 are summarized in
Table 1. Progress was madein tests of filter efficiency but it was still not possible to interTable 1— Average Concentrations of Strontium 90 in Stratospheric Samples Collected
November 1956 through November 1957*
Based on Data Available through April 14, 1958
(Strontium 90 content expressed in disintegrations per minute per 1,000 cubic feet
of air, reduced to standard conditions)
Minneapolis, Minn.
Altitude
Average
strontium 90
San Angelo, Tex.
Panama Canal Zone
France Air Force Base
Southern Hemisphere
content
Number
of
samples
Average
strontium 90
Number
of
Average
strontium 90
Number
of
Average
strontium 90
Number
of
90,000
80,000
65,000
45 + 24+
23 + 15
45 + 37
3
7
12
15 +12
28 + 13
62431
8
8
q
<3
28 +19
88 + 72
1
3
3
22419
34414
30 +12
7
10
8
50,000
19 +8
6
644
6
-
0
342
(feet)
content
samples
content
samples
content
samples
2t
* Analyses have not been completed on all samples collected during this period. The program calls for one sample a month from
each altitude at each location. In some instances the sample was not recovered.
+ Range shows one standard deviation above and below average. Standard deviations shown include both errors of measurement and
variations in strontium 90 content from month to month.
t These samples were collected within the troposphere (below the stratosphere). The 50,000-foot sampling level is usually below
the stratosphereat this location,
* Copies of Commissioner Libby’s talk entitled ‘‘Radioactive Fallout’’ were provided to the Joint
Committee. The document includes tabulations of recent data and bibliographical references to recent
contributions to the subject.
i
TP
=
35