重金属离子Cd^(2+)、Pb^(2+)污染对土壤酶活性的影响

Effects of Heavy Metals(Cd^(2+),Pb^(2+)) on Soil Enzyme Activities

通过对土壤中比较重要的两种酶(过氧化氢酶、脲酶)活性的测定,研究了重金属离子(Cd2+、Pb2+)单因素污染、复合污染对两种酶活性的影响,进而找出重金属污染程度与土壤酶活性的关系,为建立土壤中的酶活性可以表征重金属污染程度的生化指标平台提供试验依据。结果表明,在Cd2+、Pb2+单因素污染影响中,在一定浓度下的重金属离子对土壤酶活性会有激活效应,但大多表现为抑制效应;Cd2+、Pb2+复合污染对两种土壤酶活性的影响存在着明显差异,其复合污染对脲酶表现出协同抑制负效应的特征;对过氧化氢酶表现出一定的屏蔽作用。通过重金属离子形态对土壤酶有效性影响的研究,脲酶活性可以作为土壤重金属离子(Cd2+、Pb2+)单因素和复合污染程度的主要生化指标。

The effects of Cd^2＋、Pb^2＋ single and complex contamination on the two important soil enzyme （catalase, urease） activities were studied in this paper. Then the relationship between contamination degree of the heavy metals and enzyme activity of the soil was found out, on which the enzyme activity of the soil could be as a token of the pollution degree of heavy metals. The results indicated that at certain concentrations heavy metals showed activation effect on the soil enzyme activity but often inhibitory effects occured with the Cd^2＋、Pb^2＋ single agent contamination. Influence of Cd^2＋、Pb^2＋ complex contamination on the two soll enzyme activities was very different, the compound contamination of Cd2~ , Pb2~ on urease activity exhibited synergic inhibitory effect, but exhibited protective effect on catalase activity to some extent. Through the study on influences of the heavy metals to the soil enzymes, the urease activity can be served as the main bio - chemical index to the degree of the Cd^2＋、Pb^2＋single agent and complex contamination as well.