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(T/MF192) Integrated modelling approach in the risk assessment of different groups of chemicals. Fauser, Patrik1, Thomsen, Marianne1, Krogh, Paul2, 1 2 ABSTRACT- Conventional risk assessment is a combination of fate and effects of chemical substances in the environment. It is only for very few substances that a full risk assessment has been performed because of the complex nature of emissions, transport, degradation and bio-accumulation of the large number of chemicals that are emitted into the environment. Mathematical modelling is fundamental in the present and future risk assessment and to enhance the yield in informational content from experimental data a combination of different modelling techniques is necessary. In this work initial laboratory experiments investigating the fate and effects of 8 selected NSO-compounds in soil, comprising three different terrestrial organisms, have been performed. The time trends in concentration and mortality have served as input data in an integrated PCA, QSAR and fate assessment approach. Based on quantum chemical and structural descriptors, PCA is used for defining the principal components, expressing the fundamental characteristics of the substances. PLS is used for the estimation of different endpoints, such as BCF, Kd and k1. The modelled endpoints are employed in a fate and effect description of the system comprising bio-accumulation, adsorption to soil, microbial degradation and mortality. The initial experiments and integrated modelling are used to formulate an experimental design where substances that are critical with respect to the considered endpoints are identified. This approach is very efficient in identifying critical substances from the vast number of substances that are used at present or in the future and accordingly to test them in the environmental matrices of concern. Key words: risk assessment, fate, QSAR, PCA |
