Effect of Heavy Metals Cu, Cd, Pb and Zn on Enzyme Activity and Microbial Biomass Carbon in Brown Soil

To get more sensitive index for making scientific and objective judgment on heavy metal pollution in brown soil, the influence which heavy metals Cu, Cd, Pb and Zn exert on soil urease, catalase activity and microbial biomass carbon content were evaluated by means of laboratory simulation.Experiment results showed that urease activity firstly increased with the addition of Cu, Cd and Pb, then showed decline trends. But for Zn, the activity of urease was obviously decline with the increased Zn concentrations. Catalase activity firstly increased with the addition of Cu then showed decline trend. But for Cd, Pb and Zn, the activity of catalase obviously declined. Microbial biological carbon all showed decline trends with the addition of Cu, Cd, Pb and Zn.