Concentration and Source of Trace Metals in Street Dust from an Industrial City in Semi-arid Area of China

The concentrations of trace metals in street dust of Baotou, an industrial city in semi-arid area of northwest China, were determined by X-ray fluorescence spectrometry. Sources of trace metals analyzed in the dust were identified based on their concentrations, enrichment factor and multivariate statistical analysis. The results indicate that the street dust of Baotou has elevated concentrations of Ba, Co, Cr, La, Pb and Sr, which are 1.2-4.7, 4.0-10.7, 1.7-5.8, 1.0-5.1, 1.2-8.7 and 1.5-2.6 times the background values of local soil, respectively. Cr, Pb, Ba, La and Sr in the dust were moderately enriched, while Co was significantly enriched. Cu and Zn had low concentrations to moderately enriched. Other determined trace metals were of low concentrations to minimally enriched. Hf, Zr, Ti, Y, Th, U and Ni mainly originated from natural sources. Ga, Sr and Co are primarily derived from industry and construction sources. La, Mn, V, Cr, Ba, Pb, Cu and Zn have mixed natural, industrial and traffic sources.