[Quantitative structure-activity relationships of joint toxicity of 3, 4-dichloroaniline and substituted aromatics].

Acute toxicity of substituted aromatic hydrocarbons and their mixtures to river bacteria was determined by the bacterial growth inhibition test. The median inhibition concentration IC50 values for 17 single compounds and IC50mix values for 22 mixtures were obtained. The joint toxic effects of mixtures were estimated by using toxic unit and mixture toxicity index method, the mixtures of 3,4-dichloroaniline and anilines mainly exhibited simple addition or partial addition effects, whereas the mixtures of 3,4-dichloroaniline and phenols showed synergism effects. The quantitative structure-activity relationship (QSAR) models for single chemical toxicity and joint toxicity were developed by using the lgarithm of n-octanol/water partition coefficient and the energy of the lowest unoccupied molecular orbital as structural descriptors. The QSAR models contain polar narcotics and reactive compounds, and can be used successfully to predict joint toxicity of a mixture containing 3,4-dichloroaniline, whether binary mixtures in variant toxic ratios or multiple mixtures of three or four chemicals are used as predictors.