Spatial Variation of Soil Heavy Metals in an E-waste Dismantling Area and Their Distribution Characteristics

Abstract

A total of 90 soil samples were collected from the study area. The spatial variation of soil heavy metals and their spatial distribution characteristics were studied. The results indicated that the mean soil concentrations of five heavy metals including Cd, Cu, Zn, Pb and Ni were 0.38, 35.13, 121.38, 35.40 and 28.13 mg·kg-1, respectively. Compared with the background values in Zhejiang, the heavy metals were enriched in paddy soils of the study area. Part of study area was seriously contaminated by heavy metals. For the soil Cd, it had obvious contamination characteristics with a high Pi Avevalue (>1). The Cd, and Pb concentrations in paddy soil had strong coefficients of variance (C.V.): 121.05% and 109.38%, respectively. Soil pH and organic matter (SOM) had significant correlations with most of the total heavy metals and their available fractions in soils. The total heavy metals and their available fractions also had strong correlations, such as total Cd and available Cd in soils. Geostatistics and the Local Moran's Ⅰ were used to identify the contaminated hotspots of these five metals. It was found out that the high soil Cd, Cu, Zn, Pb were located in Daxi and Zeguo towns, which could be attributed to E-waste dismantling and other anthropogenic activities. Soil Ni was mainly influenced by the parent material. The heavy metals in soils may pose a potential threat to local ecosystem and human health.