| The rapid development of industry and agriculture has resulted in a series of environmental problems. Among them, soil heavy metal pollution has aroused more and more attention due to the accumulation and concealment of heavy metals and its great impacts on soil ecology, food security and human health. Soil is the habitats of microorganisms. The microorganisms are far more sensitive to heavy metal stresses than soil animals and plants in soil. Once the soil is polluted by heavy metals, the change in soil microbial community could be identified. Generally, heavy metal pollution directly inhibits the growth and metabolic processes of soil microorganisms, and then changes the microbial community, and finally destroys the stability of ecology balance. However, there is a lack of knowledge on the relationship between heavy metal contamination and soil microbial community. Therefore, conducting this kind of research will help us understand the distribution, balance, and activity of microorganisms in heavy metal polluted soils, assess soil ecology quality, and develop the technology of remediation of polluted soils.The objectives of this study are to: (1) understand the relationship between heavy metal contamination and soil biological indicators of environmental quality in paddy soils around a Copper(Cu)-Zinc(Zn) smelter in Fuyang county, Zhejiang Province. These biological indicators included microbial biomass, ability of utilizing substrates, soil enzymes, soil metabolic quotient, and microbial quotient. (2) reveal the effect of heavy metal contamination on soil microbial community by using the BIOLOG ecology plot method. (3) examine the dynamics of the microbial activity in paddy soils polluted with different levels of heavy metal in laboratory incubation conditions.51The results obtained were summed up as follows:1. Some important biological parameters, namely, microbial biomass carbon, microbial biomass nitrogen, microbial quotient, metabolic quotient and soil enzymes in heavy metal contaminated paddy soils around a Copper(Cu)-Zinc(Zn) smelter in Fuyang county, Zhejiang Province were measured for assessment of soil environmental quality. The result showed that Cu, Zn, Cd and Pb were the main heavy metal elements in the polluted area. Cu and Zn inhibited the activities of phosphatase, catalase, urease, and sucrase to different extent. A significant correlation between available Cu, Zn. Cd, Pb contents and metabolic quotient was found. Moreover, there was a negative correlation between available Cu, Zn, Cd, Pb contents and microbial biomass carbon(Cmic), microbial biomass nitrogen(Nmic), ratio of Nmic to total nitrogen, as well as microbial quotient.2. Ten paddy soil samples with different heavy metal concentrations around a smelter were used to assess the effects of combined contamination of heavy metals on soil microbial community. The results showed that the number of bacteria, fungi and actinomycetes decreased with the increase of pollution degree. Multivariate analysis of sole carbon source utilization pattern indicated that heavy metal pollution had a significant impact on microbial community structure based on the significant correlation between CV1 (canonical variatel) and contents of heavy metals. CV1 is regarded to be a potentially good indicator of soil heavy metal pollution. Stepwise regression analysis indicated that available Cu was the most significant factor controlling CV1. AWCD(average well color development) of the carbon sources in Biolog ecology polts increased significantly with time, but did not differ significantly among soils.3. We investigated the five paddy soils with different heavy metal concentrations around a Cu-Zn Smelter in Huanshan Country, Fuyang County, Zhejiang Province. The dynamic effect of heavy metal contamination on the microbial activity in paddy soils was studied through laboratory incubation experiment. Results showed that the ability of soil microorganisms to utilize substrates was negatively affected by the levels...
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