Use of theVibrio harveyiToxicity Test for Evaluating Mixture Interactions of Nitrobenzene and Dinitrobenzene

A mixture toxicity investigation was conducted using the bioluminescent marine bacteriumVibrio harveyias the test organism for dual combinations of nitrobenzene and dinitrobenzene. Change in bioluminescence was used for determination of toxicity. Combination toxicity was evaluated using statistical comparisons, isopleths (isobologram and isobole plot), an additive index, and a mixture toxicity index. Both isopleths and mixture toxicity indices suggest that various combinations are additive, while the additive index value suggests antagonism. All evaluations were conducted as equitoxic mixtures. Statistical determination was performed using theztest. Numerous comparisons were different at the 1% level. Slope of line associated with isobole plot was suggested to be an important factor, resulting in statistical differences among comparisons. Distribution, using the Shapiro7–Wilk test, was determined for both individual combination groups and solution composition in isopleths. All distributions evaluated were normal. These results suggest that theV. harveyitoxicity test is useful for mixture toxicity studies.