Source analysis and ecological risk assessment of heavy metals in suburban agricultural land soil: A case study of Laiyuan County of Baoding City

The heavy element contents in the soil of suburban agricultural land shows continuous accumulation trend. Laiyuan County of Baoding City was selected as the study area to further study the source characteristics and ecological risks of heavy metals in soil of such typical areas. The surface (0 ~ 20 cm) soil samples were systematically collected to analyze and determine the heavy metal element contents and pH value of the samples. Statistical methods, such as correlation analysis and principal component analysis, were used to study the distribution of heavy metal elements in the study area. The single factor index method and Nemerow comprehensive pollution index method were used to study the characteristics of heavy metal pollution, and the ecological risk status of soil in the region was evaluated according to the potential ecological risk index method proposed by Hakanson. The results show that the content characteristics of Cd, Hg, Pb and Zn in soil reflect the influence of human activities on soil, while As, Cr, Ni and Cu are mainly controlled by geological background factors. The heavy metal in the study area is clean, and the soil environment condition is good. The potential ecological risk in the surface soil is relatively low, and the heavy metal in soil will not cause harm to agricultural product quality and human health. But the human factors have some negative effects on soil environment, so actions should be taken to avoid the accumulation of heavy metals. The results of this study could provide scientific basis for soil heavy metal pollution prevention and control in suburban agricultural land.