- : with particular attention to significant nuclides and critical pathways ’ by which the various nuclides reach man is considered to be the best . policy to pursue. fission process. . There are about 200 radionuclides formed by the : \ w. . * -@ Fortunately for analysis, most of the radionuclides . Von are of little health consequences because of their short radiolcgical half-lives or other physical or chemical characteristics such as being one! highly insoluble. It is possible to estimate the radiation doses to various organs of the body primarily by ¢dnsidering 5 significant radionuclides that are deposited internally, i. e., ilodine-131, strontium-90, cesium-137, carbon 14 - and tritium. Question LA Can the 1968 estimated total be subdivided into meaningful categories according to half-lives? X curies of nuclides with half-lives of less than 1 day? X curies with half-lives between 1-10 days? X euries with half-lives between 10-365 days? X curies with half-lives between 1-100 years? X euries with half-lives between 100 end one million years? X ecuries with half-lives over a million years? Isn't such data essential in order to meet our future needs for containment and storage, to calculate the accumulation of uncontained nuclides, and to comprehend the ecological consequences , if any? Answer — Acurie is a unit of radioactivity and is defined as the quantity of any radioactive species in which 3.7 x 101° nuclear disintegrations occur per second. However, the definition says nothing about the types of radiation given off or their biological effectiveness to cause injury to a biological system. Categorization by half-life is inadequate for hazards evaluation