太湖沉积物重金属及营养盐污染研究

Heavy Metals and Nutrients Pollution in Sediments of Taihu Lake

通过太湖MS沉积岩芯元素地球化学指标的分析 ,对太湖沉积物污染历史进行了系统的讨论。根据化学元素的聚类分析结果、变化趋势 ,并与太湖流域经济发展进程对比 ,认为太湖沉积物铅、锌、锰、镍污染开始于 2 0世纪 70年代末期 ,砷、汞污染分别开始于 30年代和 4 0年代 ,随着底泥重金属污染程度的加重 ,沉积物表层磁化率明显升高 ;总磷自 4 0年代以来含量不断增加 ,总氮、总有机碳含量增加开始于 70年代末期 ,表明湖泊富营养化程度不断加重。太湖沉积物重金属及营养盐污染历史与该区经济发展阶段相吻合。

Sedimentation rates,element concentrations and grain sizes distribution of Cores MS and DLS sediments from Taihu Lake are investigated.According to 137 Cs dating,modern accumulation rates of Cores MS and DLS are 1.7 mm/a and 0.9mm/a.The pollution history of Taihu Lake is studied based on the geochemical characteristics in Core MS sediments.Pb,Zn,As,Hg,Mn and Ni are the main pollution heavy metals,which have different pollution history and pollution degree.The concentration of As in sediments increased since 1930s' due to the private industries development,and that of Hg increased since 1940s',which is the important pollution element due to the bio-accumulative effect.Pb,Zn,Ni and Mn pollution began at late 1970s' and the concentration in sediments became higher as As and Hg.The concentration of TP increased since 1940s',and that of TN and TOC was from late 1970s',which have close correlation with the eutrophication of lake.The history of elements pollution is correspondent with the economy development in the catchment of Taihu Lake.