摘要
Heavy metal pollution in soil is a growing concern, and little is known about how it is distributed in the soils of different districts with different land uses on a broad scale. A total of 873 surface soil samples (0- to 20-cm depth) were collected in the Huishan and Xin districts of Wuxi City. The pollution levels and sources of heavy metals in the two districts were identified using multivariate statistics and spatial analysis methods, and the results are discussed in this paper. The concentration of heavy metals in soils, particularly Hg, was higher in Xin, where there are many industrial parks. The concentrations of As, Cu, Hg, Pb, and Zn were higher than the corresponding background values in the two districts, and the soil Hg in Xin exceeded the grade II threshold value of the Chinese Environmental Quality Standard for Soils. Natural resources (e.g., geogenic and pedogenic factors) were predominately responsible for the heavy metal concentration in Huishan soils, but anthropogenic activities (industrial production and discharge) were the primary factors for soil heavy metal pollution in Xin. The soil heavy metal concentration in forestlands was high in Huishan, and among these metals Hg and As reached a moderate level of pollution [enrichment factor (EF) >2]. No pollution or minimal pollution happened in response to other land uses. In Xin, the Hg in cultivated land, rural-residential land, and underwater sediments reached a moderate level of pollution (EF >2), and the other heavy metal levels were low (EF