Indication Of Soil Enzymes Activity On The Pollution Of Heavy Metals In Soil

In this paper, the cultivated land in Xi’an was acted as the study object. The soilirrigated in normal ways in Chang’an District and that irrigated by wastewater innorthernsuburbs of Xi’an were adapted into study. The relationships between the content ofCd, Cr and Pb with the activity of the urease, invertase and catalase were discussed. Thenthe general enzyme activity index was presented on this basis, and the feasibility of this indexwas evaluated.The changes of the enzyme activity in the condition of heavy metal pollution werestimulated by experiments. The result shows that the concentration of the Cd, Cr and Pbappears negative correlation with the urease, invertase and catalase respectively in thecondition of single pollution, which manifested as inhibition. In the combined pollution,there appears a kind of notable negative correlation between Cd, Cr and urease, invertase andcatalase. So the activity of soil enzymes can be used to indicate the heavy metal pollution insoil.The principal component equation of the activity of soil enzymes was calculated usingthe PCA by the activity of soil enzymes and the contents of heavy metal in the soil samples.Then the soil samples was classified using the principal component values of the enzymesactivity and heavy metals content which obtained by the equation. Thus the general enzymeactivity index was presented. And finally the heavy metals pollution in the soil wasevaluated and the feasibility of the general enzyme activity index was tested.The results shows that the enzyme activity can be used to indicate the heavy metalspollution in the soil and the general enzyme activity index can reflect the pollution. And thegeneral enzyme activity index, to some extent, can reveal the degree of heavy metals pollutionqualitatively. But it is can not accurately show the content level of heavy metals. Whether it can indicate the heavy metals pollution quantificationally and divide the pollution degree ornot remains further study.