Quantitative aquatic toxicity prediction: using group contribution and classification methods on polar and non-polar narcotics

A model based on a Group Contribution Method (GCM) approach developed to correlate aquatic toxicity to fathead minnow (Pimephales promelas) has been applied to an external set containing 190 organic chemicals. This set was also previously partitioned into polar and non-polar toxicants using a different classification model. The application of the GCM approach to develop specific models both of the entire set and of its partitions permits to discuss the importance of the subclassification in order to improve the result.