Objective Surface waters and aquatic organisms are typically exposed to numerous chemicals simultaneously or in sequence. Consequently, hazard assessment in aquatic toxicology has to include rational approaches to predict possible combination effects. Different concepts allow to calculate expected toxicities of mixtures by analysis of concentration response relationships of their components. The recent report to the Scientific Advisory Committee on Toxicology and Ecotoxicology of the EEC concluded that the concept of concentration addition provides a reasonable basis to predict combined effects of similar acting substances. It should be applied when environmental quality norms are set. However, three questions remain to be answered: - Which criteria shall be used to classify substances as similar acting? - Is the concept of concentration addition valid for the prediction of mixture toxicities on more complex than single species levels? - What are reasonable predictions for combined effects of substances with dissimilar modes of action? The objectives of the research project PREDICT are: - to avaluate the potential of quantitative structure activity relationships (QSAR) for the prospective assessment of mixture toxicities and to optimise grouping criteria for pollutants like the list 1 chemicals of directive 76/464/EEC. - to experimentally validate predictions made from the concept of concentration addition for similar acting substances on a periphyton multispecies community test level, and - to compare the predictive values of the concepts of ,concentration addition and independent action for multi-component combinations of dissimilar acting substances especially for low, non-significant effect concentrations (EC1%) of the individual constituents. D. Calamari & M. Vighi (1991),EEC contract B 6612-90-001297 KEYWORDS : mixture toxicity; prediction; aquatic toxicology. Fields of science medical and health scienceshealth sciencespublic healthsocial sciencessociologygovernancecrisis managementmedical and health sciencesbasic medicinetoxicology Programme(s) FP4-ENV 2C - Specific programme of research and technological development in the field of environment and climate, 1994-1998 Topic(s) 02020102 - Risks to the environment Call for proposal Data not available Funding Scheme CSC - Cost-sharing contracts Coordinator UNIVERSITAET BREMEN Address 2,loebener strasse 2 28344 Bremen Germany See on map EU contribution € 0,00 Participants (2) Sort alphabetically Sort by EU Contribution Expand all Collapse all GOETEBORG UNIVERSITY Sweden EU contribution € 0,00 Address 22b,carl skottsbergs gata 22b 413 19 Goeteborg See on map Università degli Studi di Milano Italy EU contribution € 0,00 Address Via celoria 2 20133 Milano See on map