The evaluation of chemicals and the assessment of the environmental risks caused by these chemicals become increasingly important in practical environmental protection. Ecotoxicological risk assessment is used to assess the hazard potential of existing or new environmental chemicals regarding the ecosystem. Above all, two questions must be answered in this context: What are the environmental concentrations? And what are the expected effects?
The first question is answered by means of an exposure assessment, for which information on the introduced quantity, ways of introduction and the environmental behaviour of the substances is required. The expected environmental concentration is assessed with the aid of computer models. The second question is answered by assessing the hazard of a substance, considering various ecotoxicological effects such as acute toxicity, chronic toxicity and bioaccumulation. The combination of exposure assessment and hazard assessment allows the assessment of hazards induced by an environmental chemical and the analysis and final evaluation of the existing risk. Various mathematical models can be used for this purpose.
The Ecotox Centre has determined ecotoxicologically based numerical requirements (= environmental quality standards) for numerous potentially water-polluting substances, i.e. guidelines for these chemicals that must not be exceeded if a specified water quality target is to be reached.