Results from three mathematical approaches to predict the toxicity of uniform design mixtures of four heavy metals (HMs) including Cd(II), Ni(II), Cu(II), and Zn(II) and six ionic liquids (ILs) were compared to the observed toxicity of these mixtures on Vibrio qinghaiensis sp.-Q67. Single toxicity analysis indicated that the ILs had greater toxicity than the HMs. Combined toxicities of HMs and ILs were found to be synergistic. The combined toxicities were underestimated by concentration addition (CA) and independent action (IA) models. However, the mixture toxicities were effectively predicted by the integrated CA with IA based on multiple linear regression model (ICIM). We propose that ICIM model can serve as a useful tool for predicting the toxicity of interactive mixtures. (C) 2014 Published by Elsevier B.V.