中文摘要：

2002～2005年在长江中下游的洪湖、固城湖和太湖分别采集了沉积物柱样钻孔，测定了总有机碳（TOC）和金属元素包括Ph，Al，Fe，Ti等，并采用210Pb和137Cs进行了近代沉积物定年。研究结果表明，洪湖钻孔平均沉积速率为0．15cm／a，固城湖平均沉积速率在0．067cm／a，太湖平均沉积速率为0．35～0．41cm／a。根据湖泊沉积物中铅元素与参考元素（Al，Fe和Ti）浓度和TOC的相关关系建立了回归方程，线性关系极显著（P〈0．001）。根据回归方程获取了钻孔中铅的背景值变化，研究表明近代沉积物中金属铅不仅仅来源于自然的作用，而人类活动导致铅的累积发生时间都在20世纪70年代，从一个侧面也说明利用沉积物铅含量变化进行断代存在可能性。对太湖钻孔而言，其污染程度要高于洪湖和固城湖。研究结果表明近30年来洪湖和固城湖人为造成湖泊沉积物铅累积量在不断增加，其沉积物铅污染有进一步加重的趋势，应受到科学家和管理部门的关注。

英文摘要：

Sedimentary cores were collected from Honghu Lake, Guchenghu Lake, and Taihu Lake during 2002 -2005. The total organic carbon （ TOC ） and metals （ Pb, Al, Fe, and Ti） were analyzed. Combined with 137Cs or 210Pbdating method, average sedimentation rates were calculated, which are 0. 15cm/a at Honghu Lake, 0.067cm/a at Guchenghu Lake, and 0. 35 ~ 0.41cm/a at Taihu Lake. Regression model between lead and geogenic tracer elements and TOC concentration were established. The relationship between lead and geogenic tracer elements or TOC were significant （p 〈0. 001）. Pb contamination was estimated based on the natural contribution using regression model. The results imply anthropogenic lead in the three lakes. The onset of lead pollution was estimated to be in the early 1970s based on sedimentations from 137Cs or 210Pb dating method. It reveals the possibility of using lead as a time marker. The lead concentrations of Taihu Lake core are generally higher than those of the other two lakes. However,anthropogenic lead load to Guchenghu and Honghu has been increased in the recent 3 decades, which should cause the attention of scientists and lake managers.