Toxicity evaluation of five polyaromatic hydrocarbons to Escherichia coli using microcalorimetry and QASRs

The toxicity of five polyaromatic hydrocarbons (PAHs) to metabolism of Escherichia coli (E. coli) was evaluated with key parameters, including growth constant (k) and inhibitory ratio (I) from microcalorimetry analysis. The results showed that the toxicity followed pyrene > 9-phenanthrol > phenanthrene > 3-phenanthrenecarboxylic acid > naphthalene for the chemicals tested. Basing on physical and chemical parameters of these five PAHs, the quantitative structure-activity relationships (QASRs) equation was established by multiple linear regression analysis, indicating that narcosis, a non-specific and non-reactive toxic action, plays the predominant role in toxicity of these five PAHs to bacterial cells. This study illustrates that the toxicity of PAHs are determined by the number of the aromatic ring and the substituent groups, higher toxicity associated with the higher number of the aromatic rings.