Identifying the Origins and Spatial Distributions of Heavy Metals in the Soils of the Jiangsu Coast

Abstract

A total of 239 samples of surface soils were collected along the Xiangshui to Rudong coast, in Jiangsu Province, and analyzed for Cd, Cr, Cu, Hg, Ni, Pb, and Zn. A multivariate analysis was applied to identify the sources of heavy metals, and ordinary kriging was used to map the spatial distributions of the heavy metal concentration. The mean contents of Cd, Cu, Hg, Pb, and Zn in the surface soils of the Jiangsu Coastal Zone were higher than the background values of the Jiangsu Coastal Plain, which indicated that there were obvious accumulations of these heavy metals in surface soils; while the mean contents of Cr and Ni were lower than the background values. The contents of Cd, Cr, Cu, Pb, Ni, and Zn in soils that originated from marine deposition were significantly lower than those from alluvium and lagoon facies deposition, including the Yangtze River Delta deposition. Urban areas exhibited higher Cd, Cu, Hg, Pb, and Zn contents than other land covers. Cr and Ni were controlled by the parent material and seemed to originate from a natural source. Cd, Cu, Pb, and Zn were associated with the combination of parent material and anthropogenic inputs. Hg was dominated by atmospheric deposition related to various human activities. The high values of Cd, Cu, Pb, and Zn were distributed in the northern, western, and southern parts of the study area, and Hg exhibited high values around the urban areas in the western and southern parts.