Effects of Cd or/and Pb on soil enzyme activities and microbial community structure

Heavy metals could have long-term hazardous impacts on the health of soil ecosystems and adverse influences on soil biological processes. A study of Cd or/and Pb effects on soil enzyme activities and microbial community structure was undertaken with brown soil in a greenhouse for a period of 10 weeks. The experiment results showed that urease, acid phosphatase and dehydrogenase activities were significantly lower (p < 0.05) in Cd or/and Pb treatments than in control. Three enzyme activities decreased with the increasing metal concentrations. The effects of Cd and Pb combined on enzyme activities were higher than Cd or Pb alone. The soil microbial populations were far lower in heavy metal treatments than in control, and soil microbial populations under different heavy metals levels showed a significant difference (p < 0.05). The PCR-DGGE banding patterns confirmed that the addition of metals had a significant impact on microbial community structure. (C) 2011 Elsevier B.V. All rights reserved.