Risk assessment. Principles and consequences

Risk assessment is an important tool in deciding how to allocate resources to controlling risks. In most cases it is based on hazard data derived from animal experiments and on exposure data from an assessment of the likely o r actual exposure of the population of interest. Recent advances have impro ved the understanding of the use of the no adverse effect level (NOAEL) and safety factor for risk assessment by providing a scientific justification of the 100-fold safety factor. Concern about the risks of exposure by vario us routes simultaneously (aggregate exposure) and the risks of exposure to mixtures (cumulative risk assessment) have lead to new approaches to these issues. For many years, risk assessment of genotoxic carcinogens has relied on low-dose extrapolation using mathematical models. Recently, these metho ds are being reconsidered and, in some cases, replaced with the NOAEL/safet y factor approach combined with all information on the mechanism of action and the magnitude of the response. It is vitally important to ensure that r isk assessment provides accurate and unbiased estimates of risk of exposure so that appropriate measures can be taken to control the risks.