C FUNDAMENTAL CONSIDERATIONS IN DETERMINING SIGNIFICANT LEVELS OF RADIOACTIVE CONTAMINATION OF FOOD AND WATER Prepared by 410846 R_ Division of Biology and Medicine U. S. Atomic Energy Commission The radioactivity of importan:e in sea water following an atomic explosion at altitude near sea levei is principally due to fission products from the bomb which, with other materials, condense into small particles and fall into the sea. Some of this material will be retained in upper layers of water in solution, in suspension, or associated with organic materials. Radioactivity induced by the radiation from the bomb will be relatively un- important, largely because of the extreme rapidity with which it is reduced by radioactive decay. Fish living and feeding in waters containing radioactive materials will accumlate some of these materials in the various tissues of their bodies and on exposed surfaces such as the skin and gills. Observed levels of activity in sea water are too low to produce any harmful effects on the fish or on their food supply. In this connection, it may be observed that the levels of radiation required to produce observable effects on lower forms of life are generally much greater than for humans, and that the limits of radiation exposure considered acceptable for humans over periods of many years are much lower than those which would be acceptable for short periods of time. The best guide that we have available for limitation of radioactivity in food and water is National Bureau of Standards Handbook 52, which contains recommendations of the National Committee on Radiation Protection limiting the quantities of radioactive material in the body. The maximum permissible con- centrations in water, expressed as microcuries per eram, recommended in Table 3 of this handbook are considered to be applicable also to food. In setting these concentrations, it is assumed that they apply to the entire water supply of the individual (including the water contained in the food that he eats), and it is assumed that these values may be maintained throughout the remainder of his life. The figures given in Handbook 52, based largely on occupational exposure, are considered adequate at the present time, since no one is exposed to radioactive materials at considerable fractions of these values throughout his early life. The possibility of a general increase in environmental levels of radioactivity from the widespread use of atomic energy for industrial purposes has led to consideration of the desirability of using lower levels for lifetime environmental exposure. These levels might be as low as one-tenth of those acceptable for occupational exposure to radiation or to radioactive materials. US DOE ARCHIVES 326 U.S. ATOMIC ENERGY COMMISSION RG Dc & Lesbos lean DEH) Collection Box Folder foe ra ane) GQ - a DO’ ARCHIVES