ty WORLDWIDE EFFECTS OF ATOMIC WEAPONS INTRODUCTION AND CONCLUSIONS This particular report is concerned with the radioactive-biological hazard. Other possible long-range effects of nuclear bursts were briefly The bones of an individual who grows up in an environment of a maintained, given ratio of St®to natural strontium will contain Sr°° and natural Strontium in the same ratio. This assumption, in effect, is simply the assumption used in all biological tracer experiments; i.e., the body cannot distinguish between the natural and the radioactive isotopes of an element. We have not attempted in this preliminary report to define a “threshold’-damaging dosage, a “mean lethal’ dosage, etc. The terms are misleading and the magnitude of the dosages is unknown. Instead, we have normalized our studies to the Maximum Permissible Concentration (MPC) set by the International Commission on Radiological Protection. This is the amountthat,it is believed, may be retained safely in the body without causing minimal damage. 4 discussed at the SUNSHINE conference, including: 1. Loading of the atmosphere withparticulate matter—thus causing a decrease in insolation—which may affect the weather of the earth. It was suggested that the efficiency of ejection of material by large-yield bombs be compared with natural eruptions such as Krakatoa and the injection of material such as zodiacal dust. 2. Large increases in upper atmosphere ionization by radioactive debris, which may affect communications systems.” Additional long-range effects conceivably may exist; to date, however, those suggested above appear to be the most important. The popular “hazard’’—the effect of nuclear detonation on the weather—hasbeen discussed in detail elsewhere (see, for example, Ref. 3). " The MPC for Sr°° is 1 microcurie (yc) (i.e., one two-hundred-millionths ee CONCLUSIONS In assessing the hazard to a large population, it is necessary to ask who or whatis at risk as well as whatis the nature ofthe risk. The risk is simply this: The bone-retentive and radioactive properties of Sr°° endow it with a high carcinogenic capability; a given amount above threshold (which may be zero) fixed in the bone will cause a certain average percentage of the population to die of bone cancer comparable with that observed in victims of radium poisoning. Young and growingtissue is most susceptible to radiation damage; bone formation in an individual is complete by the time he is 20 years of age, although mineral exchange occurs for the rest of his life. In our model, therefore, we have taken as the individual most at risk the one who accumulates Sr°’ from the age of 0 to 20 years in a population having a severely contaminated environment. The sUNSHINE model, while containing, at the present writing, some of the uncertainties OF caller Models reparding Tanout, avallabiity SOM, etc., bypasses a numberof intermediary biologically unknownfactors by a simple assumption: *Suggestion by Edward Teller. 5 of a gram). This is an industrial standard for small numbers of people. \t may be necessary to reduce the MPC values for large populations. It is with some trepidation that we present in a preliminary report of this nature an estimate of the number of nuclear detonations that will contaminate the world. First, we fear that the concept of uniform worldwide contamination haslittle meaning and that the necessary assumptions for such a calculation are unrealistically simple, The contamination undoubtedly will occur unevenly—in “‘blobs’” over large areas—mainly because of large differences in localized fallout concentrations. Nuclear detonations occurring on a worldwide scale and possibly with a longterm “atmospheric storage” may smooth out the distribution somewhat. Secondly, differences in eating habits, disease, and environmental natural <3 strontium content of soi! will render certain populations more vulnerable to the contaminant than others. We believe the strontium ratio model to be applicable to problems of localized fallout, ethnic, and environmental differences, but the number of parameters still unknown prohibit such a calculation at the present time. We are thus forced to submit, for the present, an idealized calculation on a worldwide scale. Neglecting the question of biologically effective dosages, the parameters necessary for assessing the hazard on a worldwide scale are 1. The fraction of Sr” available for distribution as a function of type of weapon, condition of burst, and meteorology.