Pollution evaluation and source analysis of heavy metal in roadway dust from a resource-typed industrial city in Northwest China

To study the levels of heavy metals contamination and their sources, dust samples from different parts of Tongchuan, a resource-typed industrial city in Northwest China, were collected and tested for concentration of Cu, Pb, Zn, Cr, Co, Mn, Ni and As through X-Ray fluorescence spectrometry. Pollution degrees were evaluated using geoaccumulation index and Nemerow's synthetic pollution index. The investigated dust samples have elevated contents of heavy metals, except Mn, Ni and As. Cu, Pb, Zn, Cr and Co in the dust presented pollution to different degrees, while Mn, Ni and As were at low levels. The investigated dust samples were heavily polluted with metals. Principal component analysis, cluster analysis, and correlation analysis were used to analyze the experimental data and to judge the possible sources of heavy metals studied in the dusts. The results demonstrate that Zn, Mn and As had mixed sources of nature and traffic, while Cu, Pb and Cr mainly originated from traffic activity, and Co and Ni mainly came from industry and nature.