Dose–Response Analysis in Experimental Toxicology and Risk Assessment

Dose–Response, one of the primary underlying principles of toxicology, also provides us with the basis for risk assessment. It is the process of determining the point at which the response changes from an acceptable endpoint to an unacceptable one. This chapter describes the terminology used to describe some of the parameters used in risk assessment, including the concept of a threshold. Additionally, we discuss the validity of specific studies, the relevance of their endpoints to humans and the applicability of different routes of exposure to risk assessment. The process of assembling available data for review and evaluation is also discussed, as are sources of uncertainty and the different methods used in deriving risk values. Finally, the acceptability of risk is discussed as one of the critical variables in the risk-assessment process. Keywords: threshold; nonthreshold; endpoint of concern; critical effect; point of departure; benchmark dose; margin of safety; sensitive subpopulation; genetic polymorphisms; low dose extrapolation; uncertainty factor