Hydrophobicity-dependent QSARs to predict the toxicity of perfluorinated carboxylic acids and their mixtures

Abstract: Perfluorinated carboxylic acids (PFCAs) have wide industrial applications because of their unique physicochemical characteristics. However, data on the toxicity of much of this chemical class is lacking, particularly with regard to mixture toxicity. In this study, the toxicity of individual PFCAs and their mixtures to Photobacterium phosphoreum were observed. There was a tendency of increasing toxicity from C3 to C14 PFCA and a tendency of decreasing toxicity from C14 to C18 PFCA because of “the maximum tolerance of the cell membrane”. Using the equivalent log K OW (octanol–water partition coefficient) and log K SD (C18-Empore™ disks/water partition coefficient), two linear quantitative structure–activity relationship (QSAR) models were formulated. This indicated both K SD and K OW can describe the hydrophobicity of a single chemical. However, for the PFCA mixtures, K MD is the more reasonable parameter than K owmix to describe the hydrophobicity because only the equivalent log K MD could be used to predict the mixture toxicity. [Copyright &y& Elsevier]