Acute and Joint Toxicities of Hg~(2+),Ni~(2+) and Cu~(2+) to Tetrahymena thermophila

The mixture toxicity index method was used to study the toxicities of Hg~(2+),Ni~(2+) and Cu~(2+) on Tetrahymena thermophila BF_5.The acute toxicities of Hg~(2+),Ni~(2+)and Cu~(2+) were in the sequence of Hg~(2+)Ni~(2+)Cu~(2+),the median inhibition concentrations of these kinds of ions were reduced at time course.The joint toxicities of Hg~(2+) with Cu~(2+),Hg~(2+) with Ni~(2+),Hg~(2+),Ni~(2+) with Cu~(2+) at the toxicity proportion(1∶1) changed from additive to synergistic;the joint toxicity of Hg~(2+) with Cu~(2+) at the concentration proportion 1∶1,changed from antagonistic to additive;the joint toxicity of Hg~(2+) with Ni~(2+) at the concentration proportion 1∶1 changed from antagonistic to independent.The joint toxicity of Cu~(2+) with Ni~(2+) at the toxicity proportion was synergistic,at the concentration proportion was additive.The joint toxicity of Hg~(2+),Ni~(2+) with Cu~(2+) at the concentration proportion was antagonistic.