Development of in silico models for predicting LSER molecular parameters and for acute toxicity prediction to fathead minnow (Pimephales promelas).

Many chemicals with toxic effects to aquatic species are produced every year. To date, linear solvation energy relationship (LSER) models for toxicity prediction to aquatic species are limited to non-polar and polar narcotic compounds. In this study, the Verhaar scheme was used to classify chemicals into five modes of toxic actions. LSER models for predicting acute toxicity to fathead minnow were developed by identifying chemical functional groups that influence toxicity prediction of reactive chemicals. Moreover, the predictive models that can be used to estimate LSER molecular parameters have been developed by using quantum chemical and Dragon descriptors. All the predictive models were developed following the OECD guidelines for QSAR model development and validation, with a satisfactory goodness-of-fit, robustness and predictive ability. The McGowans volume was the most significant descriptor in the toxicity models. This study also inferred that, compounds with carbonyl group have different behaviors such that some can biodegrade in the organism while others do not biodegrade, which might be the reason for the difficulties in modeling the acute toxicity of reactive chemicals.