QSAR STUDY ON THE JOINT TOXICITY OF 2,4-DINITROTOLUENE WITH AROMATIC COMPOUNDS TO VIBRIO FISCHERI

ABSTRACT

The individual and joint toxicities of binary mixtures of 2,4-Dinitrotoluene (2,4-DNT) and 8 nitrobenzenes and anilines to V. fischeri were determined respectively and their mixture toxicity effects were assessed using the Additivity Index (AI). The energy of the lowest unoccupied molecular orbital (E _LUMO) of studied compounds was calculated and was used to develop QSARs. The prediction models for the individual and mixture toxicity data were respectively: log 1/EC₅₀ = 3.213 − 0.716 E _LUMO, n = 9, r = 0.830, s = 0.545 and log 1/EC₅₀ = 3.672 − 0.882 E _LUMO, n = 8, r = 0.925, s = 0.406. The joint toxic effects derived from AI values show that the mixture toxicity of 2,4-DNT and the other nitrobenzenes is synergistic (AI>0), whilst the mixture toxicity of 2,4-DNT and the anilines is antagonistic (AI<0). These results confirm that the mixture toxicity is mainly related to intracellular oxidation and reduction. −E _LUMO values of nitrobenzenes are higher. The nitrobenzenes when mixed with 2,4-DNT make the mixture systems easily reduced; the mixture toxicity effect is synergism. On the other hand, −E _LUMO values of anilines are lower. The anilines when mixed with 2,4-DNT can make the mixture systems less easily reduced, and the mixture toxicity effect is antagonism.

Keywords:

• Joint toxicity
• E _LUMO
• Log P
• Correlation

ACKNOWLEDGMENT

This work was supported by the National Natural Science Foundation of China (29877004) and the Opening Foundation of the Laboratory of Terrestrial Ecological Process, the Chinese Academy of Science.