Canonical correspondence analysis of soil heavy metal pollution, microflora and enzyme activities in the Pb-Zn mine tailing dam collapse area of Sidi village, SW China

摘要

The impacts of the Pb-Zn mine tailing dam incident on the degree of environmental response from soil properties were investigated in Sidi village, Guangxi Zhuang Autonomous Region, SW China, using statistical analysis, as well as canonical correspondence analysis (CCA). From the descriptive statistical analysis of soil properties in Sidi village, it can be seen that the topsoil pH ranged from 5.53 to 6.57, while the mean value was 5.74, which reflects the acidic and oxidized effect of the tailing sand. The total Pb in topsoil ranged from 569.50 to 6,423 mg kg~(-1), while the mean value was 1,852.33 mg kg~(-1), and the total Zn in topsoil ranged from 240.70 to 5,513 mg kg~(-1), while the mean value was 1,190.42 mg kg~(-1), which indicates that this area should not be as farmland anymore according to the environmental quality evaluation standards for farmland of edible agricultural products of China HJ/T332-2006. By analyzing the statistical analysis data and the CCA bioplot, the total Pb and the total Zn have the significant positive correlation coefficients (r = 0.656, p ＜ 0.01) and the angle between vectors of the total Pb and the total Zn is small, which confirms that the heavy metal contamination is mainly from the Pb-Zn intergrowth ore. Moreover, the soil microorganism and the total Pb-Zn are on the opposite quadrant in the CCA ordination diagram and the sensitivity of the soil microorganism to the total Pb-Zn in topsoil was observed in the order of bacteria ＜ fungi ＜ actinomyces. The soil enzyme was released by the soil microorganisms, therefore, the activities of invertase, urease, and alkaline phosphatase were inhibited into different degrees by the total Pb and the total Zn in topsoil. From the CCA biplot, their complex inwardness between the soil enzyme and the Pb-Zn contamination can be clearly and intuitively depicted. Then, the alkaline phosphatase activities have strongly positive correlation coefficients with the total Zn (r = 0.451, p ＜ 0.05) and the urease activities (r = 0.394, p ＜ 0.05).