Risk evaluation has to be the basis for the scientific development of environmental quality criteria. Risk evaluation, for all environmental compartments and receptors, is based on three aspects. The first aspect is hazard characterization. In this part information is collected over the hazard effects of a contaminant and over the dose-response relations. Exposure assessment is the second stage. The behavior of a contaminant and the risk of exposure for the potential receptors will be quantified. Finally the results of the hazard characterization and the exposure assessment will be combined. This can result in a risk characterization and / or quality standards which are based on selected criteria. This project will focus on the development of a common strategy based on this approach for the different environmental compartments.