[Quantitative risk assessment of environmental health hazards: exposure,risk and hazard].

The setting of regulations which are aimed at reducing or eliminating the effects of exposure should be preceded by the risk assessment procedures. The quantitative risk assessment is one of the methods to estimate the probability of adverse health effects caused by the exposure. In this paper the fundamental notions of exposure, risk and hazard have been discussed. The quantitative risk assessment includes four steps: hazard identification, exposure evaluation and assessment of the relationship between the level of exposure and the occurrence of adverse health effects (dose-response relationship) and risk characterization. It should be stressed that the numerical values obtained from the risk assessment should be considered in combination with other relevant data available, rather than be regarded as direct indices. Then the risk assessment will allow estimating the most likely range of risk for a particular hazard under study.