Comparison of Dose-Response Assessments for Radionuclides and Chemicals

3 Comparison of Dose-Response Assessments for Radionuclides and Chemicals 

The discussions in Sections 3.2.1 and 3.2.2 have indicated that there are important differences in the approaches to dose-response assessment for radionuclides and hazardous chemicals. An understanding of these differences is important in developing a risk-based waste classification system that applies to both types of substances. 

A fundamental difference between radionuclides and hazardous chemicals in regard to dose-response assessment is the following. Estimates of responses from exposure to radionuclides can be based on estimates of absorbed dose and equivalent dose in all organs and tissues, and the dose-response relationships for different organs or tissues obtained from human or animal studies can be applied to any radionuclide and any exposure situation. Separate studies of responses from exposure to each radionuclide of concern are not needed. For hazardous chemicals, however, quantities analogous to absorbed dose and equivalent dose have not been developed i.e., 

The following sections present a comparison of approaches to estimating deterministic and stochastic dose-response relationships for radionuclides and hazardous chemicals. 

1 Deterministic Responses. Prevention of deterministic responses is a basic principle of health protection for both radionuclides and hazardous chemicals the goal is to achieve zero probability of such responses. Incidence is the primary measure of deterministic response for any hazardous substance, although prompt fatalities also are of concern at sufficiently high doses. In risk assessments and in establishing deterministic dose limits, no adjustments are made to take into account, for example, the relative severity of different responses with regard to consequent reductions in the quality of life. 

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