A Preliminary Study on Joint Toxic Effects of Cd and Zn on Daphnia magna
水体中重金属镉和锌对大型蚤联合毒性效应的初步研究

In order to study the mechanism of joint toxic effects of heavy metals on aquatic organisms, Daphnia magna was chosen as a testing organism and the metallothionein (MT) was used as a biomarker to study the joint toxic effects of Cd and Zn. The results demonstrated that for the individual Cd or Zn exposure, with the increase of heavy metal concentrations, the contents of MT showed an upward trend (power function). However, for the Cd and Zn co-exposure, with the increase of co-exposure concentrations, the contents of MT increased first and then decreased. Cd and Zn showed synergistic effects on the MT contents at low co-exposure concentrations, additive effects at middle concentrations and antagonistic effects at high concentrations. MT is a sensitive index to estimate the joint toxic effects of Cd and Zn on aquatic organisms.