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快速检索			高级检索

区域环境与生态

基金项目：浙江省重大科技专项社会发展重点项目(No.2006C13057);国家水专项(No.2008ZX07421-001);天津市重大项目(No.06FZ2DSH00900)

摘要：太湖流域是我国经济发展最为快速的区域之一,迅速的城市化进程使该地区面源污染问题日益突出.通过对嘉兴市新塍镇的地表街尘、地表径流、受纳河网水体和沉积物样品的分析,揭示了面源污染在平原河网景观格局中和水文条件下的发生及迁移规律.结果表明,街尘作为城镇各种污染物的载体和降雨径流污染的主要来源,其5种重金属(Cr、Cu、Ni、Pb、Zn)的含量分别是122.5、152.6、90.2、172.1和319.0mg·kg^-1,高于城镇土壤和农业土壤.在城镇地表径流过程中,污染物的形态主要为颗粒态.城镇地表径流使街尘发生运移并造成受纳水体的污染物浓度较降雨前有大幅提升,其中,重金属和TSS总浓度分别增加了43%～166%和270%～510%.平原河网的水文条件和景观空间格局特征使地表径流颗粒物在进入水体后发生原位沉积,城镇段河道表层沉积物重金属含量比其他河段高.在平原河网地区地表径流的运移过程中,城镇地表是面源污染物的"源",地表街尘是面源污染物的"载体",河道是面源污染物的"汇".

Abstract：Taihu Lake Basin is one of the regions in China with rapid economic development,which brings serious urban diffuse pollution.The samples of street dust,runoff water,water and sediments from stream network were collected in Xincheng Town of Jiaxing City.The diffused pollution with the landscape and hydrological conditions of the stream network was studied.The results showed that street dust acted as a carrier of various pollutants in the town and was the source of runoff pollution.The contents of five heavy metals(Cr,Cu,Ni,Pb,Zn)were 122.5,152.6,90.2,172.1 and 319.0 mg·kg^-1,respectively,in the street dust,which were higher than that in the surface soil of the town and agricultural lands.The pollutants were mostly in particulate form in the surface runoff.The concentrations of the pollutants in the town reaching the water of the stream network were higher after rainfall than before the rain.After rain,the heavy metal concentrations increased 43%～166% and total suspended solids(TSS)increased 270%～510%.The landscape and hydrological conditions in the plain stream network made the polluted sediments accumulate at the town sites and the heavy metal contents were higher than that of other reaches.In the runoff transport process,the town street surface was the source of diffuse pollution,the street dust particles were the carrier,and the stream network was the sink.