The toxicity of binary mixture of Cu (II) ion and phenols on Tetrahymena thermophila

• The joint toxicity of Cu2+ and phenols was evaluated with the eukaryotic freshwater ciliate Tetrahymena.
• Cu2+/phenols elicited synergistic effects.
• The order of toxicity of mixtures are Cu2+/p-nitrophenol>Cu2+/o-nitrophenol>Cu2+/m-nitrophenol>Cu2+/phenol.
• FESEM and ATR-FTIR showed that Cu2+/phenols may induce effects on DNA synthesis.

The toxicity of binary mixture of Cu2+ and phenols (phenol; o-nitrophenol; m-nitrophenol; p-nitrophenol) was evaluated using Tetrahymena thermophila as the model organism, by microcalorimetry, optical density, field emission scanning electron microscope (FESEM) and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). The growth curves and metabolic properties of Tetrahymena exposed to Cu2+ and phenols were monitored by microcalorimetry. Binary mixture toxicity changed with the concentration of Cu2+/phenols and the order of toxicity was Cu2+/phenol