ABSTRACT
Uncertainty in risk assessment denotes the lack of precise characterization of risk. While the potential for health risks due to exposure to environmental pollutants is known, the level of risk cannot be precisely ascertained — it can only be estimated. The National Research Council described uncertainty in risk assessment as a problem that is large, complex, and nearly intractable. Uncertainty in risk assessment is too pervasive to describe every instance in which it can arise. Hazard identification examines whether human exposure to an environmental agent has the potential to cause a toxic response or increase the incidence of cancer. Dose–response assessment examines the relationship of dose to the degree of response observed in an animal experiment or human epidemiological study. Like hazard identification, incomplete toxicity information drives uncertainty in dose–response assessment; however, dose–response assessment is quantitative and any uncertainty is unavoidably incorporated into its calculations.
