Classification and Quantification of the Toxicity of Chemicals to Guppy, Fathead Minnow and Rainbow Trout: Part 1. Nonpolar Narcosis Mode of Action

Abstract

AbstractDiscrimination of the acute toxicity of chemicals to guppy (Poecilia reticulata), fathead minnow (Pimephales promelas) and rainbow trout (Oncorhynchus mykiss) with nonpolar narcosis and other Modes Of Action (MOA) was successfully carried out by means of discrimination analysis and structural similarity analysis. Good QSARs for acute aquatic toxicity of chemicals with nonpolar narcosis MOA for the three fish species were constructed, based on molecular polarizability and H‐bond acceptor factors calculated by the HYBOT program. These latter relationships are useful alternatives to QSARs based on the experimental parameter log Ko/w because they yield good statistics and because they are amenable to physicochemical interpretation. In this case, the acute aquatic toxicity of chemicals with nonpolar MOA is presented as the result of two contributions (molecular polarizability, which is volume‐related, and hydrogen bonding) with opposite action: molecular polarizability increases acute nonpolar narcosis toxicity and H‐bond acceptor ability decreases it.