QSAR Prediction of Aquatic Toxicity of Triazoles and Benzo-Triazoles, 6th Int. Symposium on Computational Methods in Toxicology and Pharmacology Integrating Internet Resources (CMTPI-2011), Maribor, Slovenia 3th-7th September 2011. Platform

Triazoles and benzo-triazoles (TAZ/BTAZ) are potentially hazardous chemicals that adversely affect humans and other non-target species, and are on the list of substances of very high concern (SVHC) in the European regulation of chemicals REACH. TAZ/BTAZ are synthetic molecules widely used in various industrial processes, deicing agents, pharmaceuticals and pesticides. Because of their wide use they have been found distributed throughout the environment, mainly in water compartments. The amount of experimental data available for these molecules is insufficient for a comprehensive characterization of their environmental and toxicological profile and they have been included among the four classes of chemicals studied in the European FP7 Project CADASTER. In this study QSAR models were developed for the three key organisms of the aquatic ecosystem (alga, daphnia and fish), in order to define the potential aquatic toxicological profile of hundreds of TAZ/BTAZ. In addition, interspecies quantitative correlations (daphnia-fish) were defined. Different theoretical molecular descriptors were calculated by different proprietary and freely available online software. The endpoints of interest were modeled by multiple linear regression (MLR) and the Genetic Algorithm was used to select the relevant molecular descriptors by the MLR-Ordinary Least Squares (OLS) method. The best models were validated for their robustness using leave-one-out, bootstrap and the scrambling of the responses. External validation was also performed demonstrating the high predictive ability of the models. The reliability of the predictions was always checked in order to verify the chemical applicability domain of the models to new chemicals