Effects of Single Element and Compound Pollution of Cd, Zn and Pb on Soil Enzyme Activities

By comparing Cd, Zn ac Pb single element with compound pollution in the experiment, the effects of Cd, Zn and Pb on soil enzyme activities are studied. The results show that the inhibiting effects of Cd, Zn and Ph single element as well as their compound pollution on soil enzymes have a toxicity order: CdZnPb. In the four studied soil enzymes, Urease is the most sensitive to the inhibition of heavy metals. Effect of Cd, Zn and Pb single element on soil enzymes is different from that of Cd-Zn-Pb compound pollution. Meanwhile, influence of Cd-Zn-Pb compound pollution on the four soil enzymes is different too. The characteristics of Cd-Zn-Pb compound pollution for urease exhibites synergistic inhibition effect. The three-element compound pollution for catalase activities exhibites protective effect to some extent. Under the combination of Cd-Zn-Ph, invertase and phosphatase changes significantly, mainly with the changing contents of Cd.