西溪湿地底泥重金属竖向分布规律  

Vertical distributions of heavy metals in bottom sediment in Xi-xi national wetland

作　　者：陈如海[1] 詹良通[1] 陈云敏[1] 胡洪志[2] 

机构地区：[1]浙江大学建筑工程学院软弱土与环境土工教育部重点实验室,浙江杭州310058 [2]杭州市林水局,浙江杭州310014

出　　处：《浙江大学学报（农业与生命科学版）》2010年第5期578-584,共7页Journal of Zhejiang University:Agriculture and Life Sciences

基　　金：国家自然科学基金重点资助项目(50538080);杭州市水利规划设计研究院委托项目

摘　　要：利用特制的底泥取样器从杭州西溪湿地钻取通长的底泥试样,对不同深度底泥中重金属Cu、Pb、Zn进行测试,并分析重金属在表层底泥、底泥孔隙水及上覆水中的含量及相关性,用地累积指数法对底泥的污染程度进行评价.结果表明:该湿地0.6 m深度内的底泥为轻度-中度污染,埋深大于0.6 m的底泥没有被污染或者污染程度较轻;重金属在表层底泥孔隙水中的含量显著大于其在上覆水中的含量,由于浓度梯度,底泥孔隙水中的重金属会释放到上覆水中,因此如只实施换水处理难以根除水体污染问题,疏浚受污染的底泥是更有效的治理措施.根据测试结果,0.6 m深度可作为湿地底泥疏浚的参考依据.A special sampler was made to drill out long and integrated sediment samples from Xi-xi national wetland of Zhejiang Province,and the contents of Cu,Pb and Zn in the sediments at different depths were tested to evaluate pollution degree of the heavy metals,as well as to determine their distribution along depth in the wetland using the method of geoaccumulation index.The tests and evaluation results showed that the sediments were moderately polluted within 0.6 m below the river bed,and not polluted at the depth deeper than 0.6 m.The concentration of heavy metals in the shallow sediments was found to be higher than that in pore water,which was in turn much more than that in the above water.Heavy metals in pore water of sediments could be released into the above water due to the concentration gradient,indicating that the water quality in the wetland could not be completely recovered only by replacing the polluted water with clean water,but needed to dredge the contaminated sediments in the wetland.The top 0.6 m sediment should be dredged from an economic point of view.

关 键 词：底泥 重金属 水质 孔隙水 湿地 

分 类 号：X52[环境科学与工程—环境工程]