Analysis and evaluation of heavy metal pollution characteristics contaminated soil in land-lake ecotone

Abstract

In this paper, systematic sampling with elf-made piston sampler and experiment were applied to research on the distribution characteristics of heavy metals (Cd, Pb, Cu, Zn, Cr, Ni, As) pollution in the surface and 1m depth sediments in Zhushan Bay in Zhoutie Town, Yixing City, Jiangsu Province. Spatial distribution characteristics of heavy metal elements and the relationships between heavy metals and the pH were analysed. Results show that surface and deep sediments are weakly alkaline. At the same time, the distribution of seven heavy metal elements in surface sediments in the land-water interlaced zone, estuarine and open water bodies are different. Among them, the contents of Zn and Cr are the highest, the content of Cd is the lowest, and only the content of Pb does not exceed the natural background value. The contents of heavy metals in sediments at different depths all show the distribution characteristics of Zn> Cr> Cu> Ni> Pb> As> Cd. Zn and Cr have the highest concentrations and are most likely to be pollution factors. Only Pb has no obvious accumulation and pollution is lighter. The sediments are shallow and deep, and the contents of heavy metal elements fluctuate locally. The concentration increases recently and the content in the estuary area is significantly higher. The contents of Zn, Cr, Cu and Ni are high and have a significant correlation. The correlation coefficient is between 0.680 and 0.920, showing the homogeneity of the pollutants.