Multivariate statistical analysis of heavy metals in less than 100 μm particles of street dust from Xining, China

Concentrations of Co, Cr, Cu, Mn, Ni, Pb, V and Zn in less than 100 μm particles of street dust from Xining, China were measured by wavelength dispersive X-ray fluorescence spectrometry. Correlation analysis, principal component analysis and cluster analysis were used to identify the potential sources of heavy metals in smaller than 100 μm dust. The results showed that the mean concentrations of Co, Cr, Cu, Mn, Ni, Pb, V and Zn in the studied samples were 50.0, 576.8, 40.8, 408.8, 22.6, 52.9, 57.1 and 108.9 mg kg⁻¹, which were 5.0, 8.2, 1.8, 0.7, 0.8, 2.5, 0.8 and 1.4 times the corresponding background value of Qinghai soil, respectively. Compared with Qinghai soil, Co, Cr, Cu, Pb and Zn presented accumulation with different degrees in smaller than 100 μm dust of Xining, especially Cr and Co which were markedly enriched, whereas Mn, Ni and V were deficient. Four main sources were identified based on the results of correlation analysis, principal component analysis and cluster analysis. Ni, V and Cr originated from nature (local soil) and industrial sources (steel plant, metal processing factory, coal power plant). Cu, Pb and Zn mainly derived from traffic source. Mn and Co mainly originated from local soil and construction sources (coating material and paint, etc.), respectively.