The spatial distribution and sources of metals in urban soils of Guangzhou, China

摘要

Heavy metals in urban soils are of great environmental concern because of their potential long-term effects on human health. To evaluate soil environmental quality, a total of 426 surface soil samples (0-10cm depth) were collected from different administrative districts of Guangzhou, the largest and developed city in South China. GIS-based geostatistical technique and multivariate statistics were applied to generate metal spatial distribution maps, and to identify metals influenced by anthropogenic activities. Kriging interpolation of spatial data proved to be a powerful tool in identifying the contamination hotspots and possible sources of heavy metals. Hotspot areas of metal contamination were mainly concentrated in the western and southern parts,and closely related to industrial and long-term domestic activities. Principal component analysis (PCA) results suggested the following trends: (i) Fe, Ni and Mn are predominantly derived from natural sources; (ii) As, Cu, Hg, Pb and Zn from anthropogenic sources; and (iii) Cd from both sources.