Abstract: This paper studied the metabolism of soil microbes, functions of soil microbial communities, and activities of soil enzymes in a coal mining area of Tongchuan. In the coal mining area, the concentrations of soil Cu, Zn, Cd, and Pb were significantly higher than those in the non-mining area, of which, Cd contributed most to the heavy metals pollution. By adopting Biolog method combining with principal component analysis (PCA) and cluster analysis, it was found that the metabolic characteristics of different soil microbial communities varied significantly with increasing soil heavy metals pollution, and the variation was mainly manifested in the metabolic patterns of carbon sources such as saccharides and amino acids. In slightly and moderately polluted soils, the utilization of carbon sources by soil microbial communities was activated; while in heavily polluted soils, the carbon sources utilization was inhibited. The activities of soil urease, protease, alkaline phosphatase, and catalase all tended to decline with intensifying soil heavy metals pollution. The soil urease, protease, alkaline phosphatase, and catalase activities in the coal mining area were 505%-65.1%, 19.1%-57.1%, 87.2%-97.5%, and 77.3%-86.0% higher than those in the non-mining area, respectively. The activities of soil sucrase and cellulase were activated in slightly and moderately polluted soils, but inhibited in heavily polluted soils.

Key words: heavy metals pollution, soil microbial communities metabolism, Biolog, cluster analysis and principal component analysis, enzyme activity