Source identification, spatial distribution pattern, risk assessment and influencing factors for soil heavy metal pollution in a high-tech industrial development zone in Central China

Abstract

We determined the spatial distribution pattern, source, risk level and influencing factor of heavy metal pollution in a typical high-tech industrial development zone of Changsha, China. A total of 123 topsoil samples were excavated from 11 different land-uses. Quite strong pollution (Nemerow) occurred in the whole zone. The Igeo pollution levels were from slight to strong for these elements. Four primary components were extracted from PCA with 79.36% of total variance explained. It could be deduced from the primary components that Cu, Co, Ni normally resulted from electronic industry; As and Cr were affected by both industrial and natural source; Pb and Zn were originated from traffic activities; and Cd was correlated with the activities of General equipment manufacturing industry and pharmaceutical manufacturing industry. The concentrations of Pb and Zn decreased from densely populated areas to suburbs, while the high concentrations of the other six elements were mainly found in the industrial lands. Heavy metal concentration was in weak relationship with green cover ratio (GCR) and built time, inferring that increase of GCR might not be contributed to improvement of the heavy metal pollution. While a reasonable spatial planning of land use had positive effects on controlling heavy metal pollution.