UNCLASSIFIED Biology and Medicine BIOLOGY AND MEDICINE - JULY-AUGUST 1957 Predicted Skeletal Concentrations of Strontium 90 At the suggestion of the Joint Committee on Atomic Energy, the Division of Biology and Medicine invited the principal participants in discussions on this subject at the Congressional Hearings held May 27 = June 6, 1957, to meet in Washington, D. C., on July 29 to try to reduce the degrees of uncertainty involved in various predictions of future skeletal concentrations of strontium 90 in humans. It was generally agreed by the participants that the average concentration in children of the northeastern United States in the fall of 1956 was about 0.8 micromicrocuries of strontium 90 per gram of calcium and that the average concentrations to be expected in young persons of the same area as a result of strontium 90 actually deposited on the earth's surface up to the end of 1956 fall between 1.5 and 2 micromicrocuries per gram of caleium. Three different estimates of the average skeletal levels of strontium 90 to be expected in young persons of the northeastern United States in 1975 under various conditions of testing nuclear weapons, obtained by following three different ap- proaches, are listed below. All levels are in micromicrocuries of strontium 90 per gram of calcium. Predicted concentrations in 1975 from all strontium 90 produced before 1957 lL. 2. 3, 1.5 to 3.5 @ to 5 kh to 10 Predicted concentrations in 1975 if past tests or equivalent are repeated before 1965 3.5 to 9 5 to 12 10 «to 25 The bases for these estimates are discussed in a summarypaper, copies of which may be obtained from the Division of Biology and Medicine. It was the consensus of the group that within one or two years the con-~ fidence with which predictions of future concentrations can be made will be so greatly increased that it is unprofitable for the present purpose to extend predictions beyond those given above. Food Collection Program ~- Latin America A member of the Division of Biology and Medicine staff visited Chile, Argentina, Peru, and Brazil to enlist the assistance of persons UNCLASSIFIED

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