Spatial Analysis of Heavy Metal Contamination in Agricultural Soil near a Pb-Zn Factory in a Karst Area of Guangxi, China

Soil samples were collected from farmland near a Pb-Zn factory in a karst area of Guangxi. The Zn, Pb, Cd, Hg, Cu, Ni, As, and Cr content of these samples were determined. The spatial distributions of these heavy metals, as well as the key factors affecting the distribution of the contamination, were examined. The results revealed that the means of Zn, Pb, Cd, and Hg concentrations in the samples were above the level II limit value of Chinese soil standards and showed obvious directional properties. The means of As, Ni, Cu, and Cr concentrations were near or below the level II limit value of Chinese soil standards. There was no obvious directional distribution for them, assuming coordinated geometry anisotropy. The disturbance of contamination from the Pb-Zn mining, as well as the special karst environment, was key factor, contributing to the spatial distribution of these heavy metals concentrations in the samples.