[Assessment of heavy metal contamination by moss-bag method and road-dust method for Taizhou urban area].

The aims of this study were to examine the contents and distribution character of heavy metals in urban areas of Taizhou, Jiangsu Province. Contents of 8 kinds of metals, including As, Cd, Cr, Cu, Mn, Ph, V and Zn, in the moss-bags and road dusts were determined, and the method of potential ecological risk index was used to assess the heavy metal contamination. The results indicated that the current situation of heavy metal contamination was serious in Taizhou, and the ecological risks of heavy metals were high. The mean concentrations of Cd, Zn, Pb in the air near the ground were 8.41 , 6.94 and 5. 85 times higher than the soil background values, respectively; and the mean concentrations of Zn, Cd, Pb, and Cu in the road dusts were 22. 63, 6. 58, 5. 13 and 4. 45 times higher than the soil background values, respectively. The results of potential ecological risk index showed that Cd was the main ecological risk factor both in the air near the ground and the road soils, its contribution rates in ecological risks accounted for 92.43% in the air near the ground and 72. 46% in the road soils. The Pearson correlation coefficients of heavy metals showed that there was a significant correlation among the heavy metals in the air near the ground, which implied the sources of pollution in the air were fewer than those of the road dust. Analysis indicated that traffic emission was the major anthropogenic source and the key influencing factor for heavy metal contamination of Taizhou, and that the potential ecological risk of bus stations were the highest.