中文摘要：

对白银市城郊地区土壤重金属质量分数和酶活性的测定及分析结果表明：白银市东大沟周边土壤都受到了不同程度的Ni，Pb，Cu，Zn，Cd污染，上中游污染较为严重，土壤酶活性随着重金属污染程度的加剧呈降低趋势．相关分析表明，单一的脲酶、蔗糖酶以及过氧化氢酶活性对重金属污染较为敏感，可以作为指示灰钙土分布区土壤重金属污染程度的酶活性指标．根据主成分分析法和系统聚类分析，建立了总体酶活性指标作为表示污染土壤酶活性信息系统的综合指标，表明了总体酶活性可以表征该区土壤的重金属污染状况．

英文摘要：

An analysis of heavy metal contents and enzymatic activity revealed different degrees of heavy metal （Ni, Pb, Cu, Zn, Cd） pollution along the middle and upper reaches of Dongdagou ditch, suburb of Baiying city in Gansu province. The results indicated that enzymatic activity decreased with the intensification of heavy metal pollution. Correlation analysis revealed that urease, sucrase and catalase are all sensitive to the heavy metal changes and can be an indicator of heavy metal pollution. By principal component analysis （PCA）, we established aggregative indicators of an enzymatic activity information system （N1） and also the soil heavy metal contents （M1, M2）. The cluster analysis of N1 correlated with the cluster analysis of M1 and M2. All the results suggested that the soil information system established by enzymatic activity could serve as a biochemical indicator of heavy metal pollution in soil.