Sources identification of heavy metals in urban topsoil from inside the Xiʹan Second Ringroad, NW China using multivariate statistical methods

The concentrations of Co, Cr, Cu, Mn, Ni, Pb, Zn, and V in urban topsoil samples collected from inside the Xiʹan Second Ringroad, northwestern China were measured by X-ray fluorescence spectroscopy. Correlation coefficient analysis, factor analysis and cluster analysis were used to analyze the data and to identify the possible sources of these heavy metals. The results show that the mean concentrations of Co, Cr, Cu, Mn, Ni, Pb, Zn, and V in urban topsoil from Xiʹan are 19.3, 81.1, 54.3, 671.5, 34.5, 59.7, 186.2, and 85.2 mg kg− 1 respectively, which are higher than the background values of Shaanxi soil. The mean concentrations of heavy metals in topsoil divided by the corresponding background values of Shaanxi soil increase in the order of Ni < Mn < V < Cr < Co < Cu < Zn < Pb. Analyzing the results of correlation coefficient, factor analysis and cluster analysis, three main sources of these heavy metals were identified. Pb and Cu originate from traffic. Co, Cr, and Zn mainly derive from industry sources, traffic and garbage, while Mn, Ni, and V mainly originate from natural source.