Secondary Standards Derived from ICRP Basic Safety Standards

The derivation of secondary standards from the basic recommendations of the ICRP are discussed. The secondary standards are evolved from maximum permissible doses to body organs, taking cognizance of the physical and physiological characteristics of the standard man. The premises for derivation of secondary standards on the basis of such factors as body and organ weights, au and water (and food) intake, intake of elements, tissue concentration of elements and other biological parameters are examined for applicability to Indian conditions. Substituting some of the above factors applicable for Indians, the values of which are available, revised MPCW values foe a few radionuclides are obtained. It is emphasized that investigations on these lines should be encouraged so that norms applicable to man living in different regions of the world could be evolved. Limitations In using secondary standards, especially MPCW, directly for occupational workers are discussed. The importance of investigating the concentration factors for radionuclides in food items and their effects on MPCW values are demonstrated. The implications of using the specific activity concept to prescribe acceptable discharge limits are discussed. Limitations of direct radiation monitoring in the environment and the usefulness of indicator organisms for environmental monitoring are indicated. (author)