芜湖市区春季地表灰尘中汞和砷的空间及粒径分布规律

Spatial and particle size distribution of mercury and arsenic on surface dust in spring in the Wuhu urban district

以芜湖市高新技术开发区、中心城区和经济技术开发区为研究区域,于2008年春季对其地表灰尘中汞和砷含量、空间分布特征及其在粒径中的分布规律进行了研究.结果表明:芜湖市区地表灰尘中汞、砷含量范围分别为0.011～1.477mg·kg-1、3.533～169.368mg·kg-1,平均值分别为0.230、15.371mg·kg-1,分别是土壤背景值的1.9和1.5倍,存在一定程度的污染;;灰尘中汞含量在经济技术开发区较高,而砷则在高新技术开发区出现高值区;;汞属于空间中相关,说明其变异主要受随机或人为因素的影响;;砷属于空间强相关,说明其变异主要受土壤母质、土地利用方式等因素影响;;研究区地表灰尘汞和砷含量大体上呈随粒径减小而增加的趋势;;不同粒径上汞和砷含量的富集比例随粒径减小呈增加的趋势,汞和砷在>200目粒径上的平均富集比例分别为63.5%和55.8%,说明汞更容易富集在细小颗粒上.

Mercury ＆ arsenic contents in Wuhu urban area dust, their spatial characteristics and particle size distributions were studied in the spring of 2008 in three districts（ High-tech Development Zone, City Center,Economic and Technological Development Zone）. The Hg ＆ As concentrations in the study districts were 0.011 - 1. 477 mg·kg^-1 and 3. 533 - 169. 368 mg·kg^-1 respectively. The mean concentrations of 0. 230 mg·kg^-1 for Hg and 15. 371 mg·kg^-1 for As were 1.9 and 1.5 times the soil background values. The Hg concentration was high in the Economic and Technological Development Zone, but As content was high in the High-tech Development Zone. Hg fit the middle spatial correlation which indicates that Hg is mainly influenced by the stochastic or human factor; As fit the strong spatial correlation, so it is mainly influenced by parent material of the soil, or land uses. In general, Hg and As concentrations increased as the particle size of the surface dust decreased, and the enrichment ratio showed the same tendency. The enrichment ratios of Hg and As were 63.5% and 55.8% respectively in the 0. 074 mm particles （ 〉 200 mesh）, which shows that Hg is enriched on the tiny particles.