A QSAR study on the biodegradation activity of PAHs in aged contaminated sediments

The relationship between the chemical structure and biodegradation activity (− logt1/2) of 17 polycyclic aromatic hydrocarbons (PAHs) was studied using density functional theory (DFT) and stepwise multiple linear regression analysis (SMLR) methods. The equilibrium geometries and vibration frequency have been investigated at B3LYP/6-31 + G(d,p) level. One high correlation coefficient was found between the wagging vibration frequency (Freq) of the whole molecule and − logt1/2, which is resulted by the special structural characteristic with a big conjugated system. By means of regression analysis, the main factors influencing biodegradation activity were screened, and the equations of quantitative structure–activity relationship (QSAR) were established. The evaluation of the developed QSAR showed that the relationships are significant and the model had good predictive ability. The QSAR model showed that the biodegradation activity was closely related to molecular structure: the chemical bond strength of benzene ring played an important role in biodegradation process; In addition, low molecular weight PAHs are more degradable than the high molecular weight compounds.

► The equilibrium geometries and vibration frequency have been investigated.
► The main factors influencing biodegradation activity were screened.
► The equations of quantitative structure-activity relationship were established.
► The QSAR model has good robustness and predictive ability.