ABSTRACT
Ecotoxicity tests provide an efficient way to control industrial effluents and to minimize their environmental impact. In the examination of sewage, these tests can replace to a certain extent the routine analyses of chemical substances. For that purpose several biotests are available as standardized procedures. In Germany, biotests are already used to define emission limit values. Fish, daphnia, algae and bacteria were chosen as representative test organisms of the ecological relevant trophic levels. However, the test procedures, with their advantages, their problems, their reproducibility and their ecotoxicological relevance require to be critically reviewed. The application of biotests for an estimation of the ecological quality of surface waters or for the industrial selfcontrol of process water complete the view on the toxicity assessment on industrial wastewaters.
