泰州市区重金属污染的藓袋法与路尘法评价研究

以泰州市区为例,分别用藓袋法和路尘法对城市近地面空气与道路灰尘中As、Cd、Cr、Cu、Mn、Pb、V、Zn等8种重金属污染物的含量与污染特征进行了分析,并用潜在生态危害指数法评价了其生态危害程度.结果表明,泰州市城区重金属污染较为严重,存在较高的潜在生态风险.近地面空气中Cd、Zn和Pb这3种重金属的平均含量分别达到了土壤背景值的8.41、6.94和5.85倍,道路灰尘中Zn、Cd、Pb和Cu的平均含量是背景值的22.63、6.58、5.13和4.45倍.重金属潜在生态危害评价结果表明,Cd是近地面空气与道路灰尘重金属潜在生态风险偏高的主要因子,其生态危害贡献率分别达到了92.43%和72.46%.相关性分析表明,近地面空气中的重金属来源相对单一,各重金属之间表现出较高的相关性.汽车尾气是泰州市城区重金属污染的主要来源,客运车站是重金属潜在生态风险最高的地区.

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, Pb, 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.