ENTRY OF RADIOACTIVE FALLOUT INTO THE BIOSPHERE AND MAN™ Wright Langham and E. C. Anderson Los Alamos Scientific Laboratory of the University of California, Los Alamos, N. Mex. Dr. Wright Langham and Dr. E. C. Anderson of the Los Alamos Scientific Laboratory, have prepared a comprehensive review paper discus- sing world-wide fallout. Because of its excellence as a summary, the Joint Committee on Atomic Energy requested permission to publish the paper last year in the printed hearings on “The Nature of Radioactive Fallout and Its Effects On Man” (p. 1348). The paper is scheduled to appear in Vol. 1, Number 2, 1958, of Health Physics, official journal of the Health Physics Society. The title will be, “Potential Hazard of Strontium-90 from Nevada Weapons Testing.” In the light of information appearing in the past year, Dr. Langham and Dr. Anderson updated their paper and presented it before the Swiss Academy of Medical Sciences. We have especially asked for permission to reprint the updated paper here, and wish to acknowledge the permission granted by the authors, the Health Physics Society, and the Swiss Academy. The present paper will appear in the Bulletin of the Swiss Academy of Medical Sciences 14, 1958, Basle, Benno Schwabe & Company, 2S part of the Symposium on the Noxious Effects of Low Level Radiation at Lausanne, Switzerland, March 27-28, 1958. 1 INTRODUCTION Discussion of the potential hazard of world-wide radioactive fallout from nuclear weapons tests may begin with the consideration of three basic facts. 1. The world population is receiving small exposure to radioactive materials originating from nuclear weapons testing. Fission products from bomb detonations have been and are being deposited over the surface of the earth, increasing the external gamma radiation background and finding their way into the human body through inhalation, direct contamination of food and water, and by transmission along ecological cycles from soils-to-plants-to-animals and to man. . 2. Enough radiation, either from an external source or from radioactive isotopes de- posited in the body, will produce deleterious effects. These effects may result in an increase in genetic mutations, shortening of life expectancy, and increased incidence of leukemia and other malignant and nonmalignant changes. 3. Radiation exposure is not a new experience for the world population. All life has been exposed to radiation since the beginning. Radiation from cosmic rays, from radioactive min*Prepared for the Swiss Academy of Medical Sciences’ Symposium on the Noxious Effects of Low Level Radiation, Lausanne, Switzerland, March 27—29, 1958. 282