| This paper takes soil of Xinzhuangzi Coal reclamation area in Huainan city as the research object. The relationship between the activity of soil enzymes and soil pollution were discussed by refining the study of spatial and temporal distribution of soil enzyme activity, and the influencing factors (soil microorganisms, soil physical and chemical properties, soil heavy metals and so on). And the spatial and temporal variation of soil enzyme activity and the feasibility of heavy metal pollution evaluation were analyzed for providing certain basis to filling reclamation of coal mine, functional recovery and ecological management of reconstructed soil, and the proper evaluation of the security of reclamation area reconstructed soil as normal use of cultivated land. On the basis of contamination evaluation of the reclamation area, the relationship between soil heavy metal pollution and soil enzyme activity were clarified. And the quantitative inhibition rule of three kinds of heavy metal (Cd, Pb, and Cr) pollution to soil urease and catalase activity through laboratory simulation.The main conclusions of this paper are as follows:(1) Soil enzyme activity showed a certain amount of temporal and spatial distribution characteristics. By studying activity value of seven kinds of soil enzyme (urease, phosphatase, protease et al.) in Xinzhuangzi reclamation area, it can be found that soil enzyme activity showed certain regularity in different seasons, different sampling depth. Compared with the control, the soil enzyme activity was in a certain degree of inhibition, and the inhibition degree was inconsistent. The distribution of soil catalase activity was not obvious. Polyphenol oxidase showed otherness trend comparing with the other six kinds of enzyme. It had certain uniqueness and surpassed the value of the control point. With the change of seasons, soil enzyme activity presented the distribution of unimodal curve. Under the three sampling profile, soil enzyme activity presented level distribution characteristics.(2) Through the analysis of seven kinds of soil enzyme and the impact factors of soil microbial (bacteria, fungi, actinomycetes) quantity, soil physical and chemical properties, the content of soil heavy metal, soil respiration and so on, it can be seen that it has certain relevant relationship between soil enzyme activity and these impact factors. Bacteria showed significant positive correlation with soil phosphatase, protease activity at the0.01level, and presented positive correlation with soil urease, invertase activity at the0.05level. Actinomycetes were significantly correlated with soil cellulase activity at the0.01level. The numbers of fungi were related to protease, sucrase, phosphatase at certain extent, but the correlation was not significant. The total soil microorganisms were significantly correlated with soil urease activity at the0.05level, and were highly significant related with soil phosphatase, invertase, and protease at the0.01level. There was positive correlation between soil invertase, cellulase activity and pH value. There was negative correlation between catalase, ployphenol oxidase and pH value. Soil cellulase activity and soil redox potential presented certain negative correlation. There was a positive correlation between soil catalase, polyphenol oxidase activity and soil redox potential. The soil available K has certain positive correlation between soil catalase, polyphennol oxidase activity. The soil available P has certain correlation with the activity of polyphenol oxidase. The effect of heavy metal pollution on soil enzyme activities presented different degrees of inhibition generally. Soil respiration significantly correlated with protease, phosphatase and catalase at the0.01level, and correlated with urease at the0.05level.(3) This paper focused on soil enzyme activity isolated from Xinzhuangzi reclamation area and surrounding farmland soil. It could be found that the soil enzyme activity of reclamation area subjected to different degrees of inhibition. The principal component factors derived using principal component analysis, thereby establishing compound contaminated of general activity index of soil enzyme to evaluate the condition of soil contamination. The results showed that the comprehensive evaluation of soil enzyme activity deduced by principal components analysis was basically consistent with the heavy metal pollution of soil using the grey clustering method based on grey theory. It showed that the overall activity index of soil information system built by the soil enzyme activity to characterize the condition of heavy metals compound contamination in soil was feasible.(4)Under the conditions of laboratory simulation, the researches were conducted by both individual and combined heavy metals pollution (Cd, Pb and Cr) in different levels espousing upon the soil urease and catalase for providing enzymology indexes of environmental risk assessment and remediation of heavy metal pollution in soil. The results indicated that soil urease and catalase activities were subject to different degrees of inhibition. The inhibition of the three heavy metals was reached the maximum state together under the minimum activity of soil enzyme, which has demonstrated that a significant negative correlation relationship between the toxicity of heavy metals and activity of soil enzymes. Therefore, the activities of urease and catalase were available for characterizing polluted degree by heavy metals (Cd, Pb and Cr) in the soil. Meanwhile, there was weak interaction between soil enzymes and heavy metals, the activation was reflected in low concentration condition, yet the antagonism was reflected in high concentration. The best fitting-curve obtained by quantitative analysis in compound pollution condition. It provides reference for the enzyme indicators to establish the evaluation for heavy metal pollution in soil, and theoretical guidance for environmental monitoring and restoration in soil as well. |
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