36 WORLDWIDE EFFECTS OF ATOMIC WEAPONS 4. Since Sr°° very probably fractionates, the Sr’ content of fallout samples for various representative stations and for varying periods of time after the test should be measured.” 5. If posstble an attempt should be made to determine the chemical and physical form of the Sr°° in the fallout material. CHAPTER 4 BIOMEDICAL CONSIDERATIONS REFERENCES DEFINING THE MEDICAL PROBLEM 1. Derant, A., “Die Zirkulation der Atmosphire in den germassigten Breiten der Erde,” Geogr. Annaler, Stockholm, Vol. 3,.1921, pp. 209-265. 2. EISENBUD, MERRIL, AND JOHN H. HarLey, “Radioactive Dust from Nuclear Detonations,”’ Science, February 13, 1953, Vol. 117, No. 3033, pp. 141-147. 3. The Effects of Atomic Weapons, Los Alamos Scientific Laboratory, June, 1950, U.S. Government Printing Office, Washington 25, D.C. From the biomedical point of view, any attempt to define the lower limit of hazard (exclusive of immediate bombeffects) from theeffects of atomic bombing or other atomic energy releasing devices, must be concerned with the problem of radioactivity. The effects of such things as climatologic changes, dust, etc., do not seem to enter into the picture at -78 “The NYOOis making assays on the combined Sr8*, Sr®° content of past samples collected in the TUMBLER/SNAPPER and Ivy operations. Preliminary results are given in Chapter 5. levels where radioactivity is already assuming considerable importance. Radioactivity has many effects on the human body, but a quantitative search for the lower limit of hazard rapidly eliminates the short-term acute effects and even the chronic gross-tissue effects, such as necrosis. The problem of a lowerlimit of hazard, then, enters the realm of carcinogenic and genetic effects. At the present time the data available do not permit a serious evaluation of the genetic problem. It is probable, however, that even when a reasonable estimate of genetic effects can be made, carcino- genic activity will still remain the limiting factor. The present study, therefore, narrows down to the hazard of carcino- genic activity due to the fission products released. The prevailing opinion of workers in this field indicates that Sr’? is the mostlikely limiting factor by several orders of magnitude when one considers the products released by atomic bombs, Although we have made no quantitative comparison between Sr*° and other fission products, we may indicate the importance of the selected isotope because of the following: 1. It is produced in considerable quantity by the atomic bomb (e.¢., TR produces I pm of ory. 2. It is produced in a manner that suggests thatit will be in a soluble form and therefore readily available for incorporation into the biosphere. 37