淮南市城区地表灰尘重金属分布特征及生态风险评价

城市地表灰尘中重金属会对人体健康和生态环境产生危害，为研究城市中不同功能区地表灰尘重金属的含量和潜在生态危害水平，以典型煤炭资源型城市淮南市的地表灰尘为研究对象，采集工业区、商业区、交通区、文教区、居住区和公园绿地等6种功能用地共40个点位的地表灰尘。采用电感耦合等离子体发射光谱（ICP-OES）和DMA-80直接测汞仪测定Zn、Pb、Cu、Cr、Cd、Ni、Co、V、Hg的含量，分析其在不同功能区地表灰尘中的分布特征、相关性及可能的来源；并应用潜在生态危害指数法对重金属在不同功能区的潜在生态危害进行评价。结果表明：1）淮南市地表灰尘中 Zn、Pb、Cu、Cr、Cd、Ni、Co、V、Hg的平均质量分数分别是202.59、74.63、62.74、110.69、0.57、35.82、12.18、50.95和0.105 mg·kg-1，其中Zn、Pb、Cu、Cr、Cd、Ni、Hg的平均含量分别是淮南市土壤背景值的3.47、3.17、2.04、1.21、9.50、1.12、2.56倍，是中国土壤背景值的2.73、2.87、2.78、1.81、5.88、1.33、1.62倍。2）9种重金属中，Zn和V的含量在不同功能区分布相对均匀，其他重金属在不同功能区含量均表现出较明显的空间异质性。3）不同功能区中，Zn、Pb、Cu、Ni、Co、V、Hg的平均含量在工业区最高，Cr 和 Cd 的平均含量在交通区最高。4）不同重金属的相关性表明，Zn、Pb、Cu、Cd、Ni 等5种元素有同一来源，Co 和 V 有同一来源。5）单项潜在生态危害系数大小为 Cd〉Hg〉〉Pb〉Cu〉Ni〉Co〉Zn〉Cr〉V。不同功能区9种重金属复合生态危害均处于强生态危害水平（300≤RI〈600），其中工业区和交通区潜在生态危害水平最高。

Distribution and Ecological Risk Assessment of Heavy Metals in Urban Dusts of Huainan city

Heavy metals in urban dust are harmful to human health and environment. In order to investigate the contents and potential ecological risk of heavy metals, urban dust samples in typical coal resource-based Huainan city were collected from forty points covering six functional zones, i.e. industrial areas, commercial areas, traffic areas, educational areas, residential areas and public landscapes. Total contents of Zn, Pb, Cu, Cr, Cd, Ni, Co, V and Hg were measured by inductively coupled plasma-optical emission spectrometer （ICP-OES） and direct mercury analyzer （DMA-80）. Distribution characterizations, correlations and possible sources of Zn, Pb, Cu, Cr, Cd, Ni, Co, V and Hg were analyzed. Potential ecological risk index was adopted to estimate the potential ecological risk of heavy metals in urban dust of six functional zones. Our study shows that： 1） the average concentrations of Zn, Pb, Cu, Cr, Cd, Ni, Co, V and Hg were 202.59, 74.63, 62.74, 110.69, 0.57, 35.82, 12.18, 50.95 and 0.105 mg·kg-1; Zn, Pb, Cu, Cr, Cd, Ni and Hg were 3.47, 3.17, 2.04, 1.21, 9.50, 1.12 and 2.56 times higher than the Huainan soil background values, respectively, and 3.47, 3.17, 2.04, 1.21, 1.12 and 2.56 times higher than Chinese background values, respectively. 2） The concentrations of Zn and V in different functional zones were rather evenly distributed, whereas the rest elements were distributed with large spatial heterogeneity. 3）Zn, Pb,Cu, Ni, Co, V and Hg were ranked as the top toxic elements in industrial area, and Cr and Cd were ranked as the top toxic elements in traffic area. 4） The corrections among heavy metals indicated that Zn, Pb, Cu, Cd and Ni shared common sources; so did Co and V. 5） The descending order of pollution degrees of the individual metals is： Cd〉Hg〉〉Pb〉Cu〉Ni〉Co〉Zn〉Cr〉V. Heavy metals in urban dusts of different functional zones reached the strong ecological risk levels, industrial areas and traffic areas reached the highest.