ee se ee Part Vil, Biology and Medicine ae Project ‘SUNSHINE (UNCLASSIFIED) Summary statements on the status of research on the fallout of radioactive materials from nuclear detonations have been presented in the Quarterly Progress Report, July-September ~- 1956, inthe Twenty-first Semiannuai ‘Report to the Congress, and in speeches by AEC offi-_ cludesthe activities described below: Stratospheric sampling. Techniques are being developed to make possible the monitoring of radioactive fission products in the stratosphere. Such measurements would provide impor- - tant information on quantities of weapon debris reaching the stratosphere,thedistribution and _ retention of such materials in the stratosphere, and their release to thelower atmosphere. In ‘experiments now being conducted with the Departmentof Defense, balloons are being ‘used 1 to eeeh ith ‘cials.* Present work on Project SUNSHINE (the study o¢ f theJong-rangeeffectsof fallout) in- . carry sampling equipment to altitudes of 50,000 to 90,000 feet, where radioactive particles are filtered from a defined volumeof air. Balloon-launching sites are at Minneapolis, Minnesota; San Angelo, Texas; France Air Force Base in the Panama Canal Zone, and a point in the Southern Hemisphere. ~ . , Ho, ‘ Strontium 90 is considered to be a hazardous fission product for of the “food chain” from soils to humans; and (3) a large proportion of the strontium 90 ingested is depositedin the bone andis only slowly eliminated from the body. The occurrence of 3 : Studies of strontium 90. three reasons: (1) its radioactivity is relatively long-lived; (2) it is readily transferred by way Aepats de bPhd ‘Radiochemical analyses of the samples are» being made-on a pilot acale by the AEC Health and Safety Laboratory, New York, until arrangements can be made with commercial laboratorie to perform this work. Results of thesestudies will be useful in planning a worldwide network for the stratospheric monitoring of long-lived radioisotopes. “ dietary habits. The biological effects of strontium 90 on large animals, -particularly-dogs, are being studied in expanded research projects at the University of Utah and the University of | California at Davis. These experiments with animals may permit more precise estimates of —the effects which various concentrations of strontium 90 may be expected to have in human populations when maintained in the skeleton for long periods of time. Even preliminary results from thesestudies cannot be expected in the near future, and complete resulis 3 may not be available for as many.as 15 years. wet . . . *Speech by Commissioner Willard F: Libby before the American Association for the Advancementof Science, Washington, D. C., October 12, 1956. Speech by Merril Eisenbud, Director of the AEC Health and Safety. Laboratory, New York, before the Washington Academy of Sciences, Washington, D. C-. November 15, 1956. UNCLASSIFIED “53 a eeepee Lenlebige st ee strontium 90 in humans is being given greater attention in. research projects in order to deter-. mine the importanceof such factors as geographic location, calcium content of soils, and local’

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