Quantitative structure-activity relationship (QSAR) study of toxicity of quaternary ammonium compounds on Chlorella pyrenoidosa and Scenedesmus quadricauda

► Quaternary ammonium compounds (QACs) were highly toxic to green algae. ► Chlorella pyrenoidosa was more sensitivity to QACs than Scenedesmus quadricauda. ► The QSAR models have been developed to predicting the toxicity of QACs to the two algae. ► Topological descriptors and geometric descriptors of the QACs were the dominant factors affecting the toxicity.