Soil Enzyme Activities And Pb, Zn Pollution Study On Lead-zinc Mining Area In Hanyuan Dry And Hot Valley

In this paper, soil samples with lead-zinc collected from three typical lead-zinc districts of Tangjia, Wusi river and Fuquan in Hanyuan, were used to determine lead and zinc contents, activities of the catalase, dehydrogenase, urease, protease, invertase, amylase, cellulase, neutral phosphatase, alkaline phosphatase and changes of the total DNA contents of microbes in the soil. By means of mathmatical analysis and establishing the total enzyme activity indexes which were based on the enzymes mentioned above, this study comprehensively evaluated the degrees of the lead and zinc pollution in the three districts, to provide scientific basis for the restoration of the lead-zinc soil in lead-zinc mining areas of dry-hot valley. The results were as follows:1. The soil enzyme activities changed regularly in different lead-zinc distrcts. As the distances of the soils in the lead-zinc mining area of Fuquan from slag areas increased, the activities of the soil catalase, dehydrogenase, urease, amylase and neutral phosphatase showed the increasing tendencies. So did the alkaline phosphatase in the lead-zinc mining area of Tangjia.2. Correlation analysis showed that soil lead and zinc contents of lead-zinc mining areas and the soil enzyme activities had negative correlation. And, the activities of the soil catalase, dehydrogenase, urease, amylase and neutral phosphatase, the total contents of lead and zinc and the available lead and zinc contents demonstrated the significant or highly significant correlation. While in the lead-zinc mining area of Tangjia, the correlations were significant or highly significant among the total lead and zinc contents, the available lead and zinc contents and the activities of the soil catalase, cellulose, alkaline phosphatase. By comprehensive analysis of the data from the three lead-zinc mining areas, the total contents of the soil, the available lead-zinc contents and the activities of the soil catalase, dehydrogenase, protease, urease, amylase, neutral phosphatase and alkaline phosphatase showed the significant or highly significant correlation.3. Regression analysis indicated the activities of the soil catalase, dehydrogenase, amylase, neutral phosphatase and alkaline phosphatase were significantly correlated with the soil lead and zinc contents.4. The total DNA contents of the soil microbes in the lead-zinc mining areas were highly negative correlation between the soil lead and zinc contents and the available lead and zinc contents. The correlation coefficient of the total DNA contents of the soil microbes and the soil activities was positive. And the total DNA contents of the soil microbes were highly significant correlation with the activities of the soil dehydrogenase, urease, amylase, protease, neutral phosphatase and alkaline phosphatase; and significant correlation with the soil dehydrogenase. It demonstrated that the method which was used to evaluate the degrees of lead-zinc pollution by the soil enzyme activities was reliable.5,Principal component analysis illustrated that the sum of variance contribution rates of the first to the fifth principal components of the nine soil enzyme activities in the lead-zinc district reached 85.63%. Through establishing five-principal-component equations based on the first to fifth principal components, then obtaining the integrated equations according to the weight of the five-principal-component variance contribution rates, and building the indexes of the soil total lead-zinc contents which could comprehensively reflect the nine soil enzyme activities and the indexes of the total lead and zinc contents and the available lead-zinc contents of the soils, this experiment classified the soil sampling areas by the total enzyme activities of soil, and its result was consistent to that by the total lead and zinc contents of soil. It verified that it was quite accurate to use the total enzyme activities of soil to evaluate the degree of the lead-zinc pollution.6,The total enzyme activities of soil was highly negatively corelated with the total lead and zinc contents of soil(r=-0.662**),which was higher than the correlation between single soil enzyme activity and the total lead-zinc content of soil. It could clearly be seen that,the total enzyme activities of soil were better than single enzyme activity of soil to evaluate the degree of the lead and zinc contaminated soil.7,The indexes of the soil total enzyme activities could better reflect the degrees of the soil lead-zinc pollution in the study mining areas in this paper.