[Spatial Distribution and Risk Assessment of Heavy Metal Contamination in Surface Farmland Soil Around a Lead and Zinc Smelter].

Surface farmland soil samples were collected from 135 different sites in a 64 km area around a lead and zinc smelter in Jiaozuo City, China. The concentration of the selected heavy metals (Cu, Zn, Pb, Cr, Cd, Ni, V, and Co) was analyzed and the spatial distribution of these heavy metals in the farmland was determined using the kriging interpolation technique (ArcGis 10.1). The enrichment factor, potential ecological risk model, and potential health risk model were used to assess the contamination level and potential risk of heavy metals in farmland surface soil. The results show that the average contents of Cd, Pb, Cr, and Zn in farmland soil are higher than the background content of these metals in the Henan Province and the average content of Cd is 2.8 times higher than that of class Ⅱ of the environmental quality standard for soils in China (GB 15618-1995). The heavy metal contamination in the west of the study area is higher than that in the east and the soil around the lead and zinc smelter (within 3 km) is severely contaminated with Pb and Cd, which is consistent with the location of the industries causing the pollution. The enrichment factors show that the soil is severely contaminated with Cd; partial sampling points are seriously contaminated with Pb, Cu, and Zn; the Cr and Co pollution is small; and Ni and V are almost not affected by human activities. The results of the risk assessment indicate that Cd poses serious ecological and health risks, Pb and Cu pose serious ecological risks, and Cr poses a serious cancer risk.