HEAVY METAL POLLUTION AND THE ECOLOGICAL RISK ASSESSMENT OF URBAN STREET DUST IN KUNMING, CHINA

The concentration of Cu, Ni, Cr, Zn, Pb and As in urban street dust collected from Kunming were analyzed by using X-Ray fluorescence spectrometry. Spatial technique was applied to study the content level and the spatial distribution character of heavy metal pollution in street dust of Kunming. The ecological risks of heavy metals in street dust were assessed by the potential ecological risk index (ERI) method. The results show that the average concentrations of Cu, Ni, Cr, Zn, Pb and As were much higher than the background concentrations of soil in China, in which Cu, Zn, Pb and As have reached the relative enrichment classes, these four elements heavier pollution. Accumulation of heavy metals in the dry season was significantly higher than during the rainy season. The highest content of heavy metals was in the industrial areas, the followed were the traffic areas. Heavy metals mainly came from traffic pollution in urban street dust and industrial pollution in Suburbs. The potential ecological risk level of heavy metals in street dust of Kunming reached the lightly ecological risk levels.