Abstract: The heavy metal pollution of Taizi River has been evaluated using Excess after Regression Analysis method proposed by Hilton. The concentration of heavy metal within a sediment core has been modelled by considering three components, the background concentration(Cb), that due to accelerated erosion (Ca), and an anthropogenic pollution term (Cp). Major cations associated with clay minerals such as Al, K and Mg do not have a pollution component. Iterative regression of the heavy metal concentration against one of these elements permits the isolationof Cp. Two group of heavy metals were identified. Type A(Zn and Cd)did not have a component due to accelerated erosion Ca. They are thought tohave passed through a solution phase before being recruited to the sediment. Type B metals (Fe, Ni, Cu and Pb)correlated well with the claymineral elements and were probably transported to the sediment as particles. We developed the ERA method because the heavy metal pollution level can't be identified by it. As a result, the developed ERA method makes it easy to compare the heavy metal pollution in different regions. After this study, we can draw the following conclusion: Copper and lead pollution are most serious in Taizi River; The heavy metal pollution is serious in the middle section of Taizi River, especially in Hejingou section. But Niuxintai section has no heavy metal pollution and Baishi section has little.

Key words: sediment, heavy metal, pollution, Taizi River, excess after regression analysis

摘要： 回归过量分析法（ERA）是Hilton等人提出的一种新的评价沉积物中重金属污染的方法。该方法的特点是将沉积物中重金属的浓度分为3部分，即背景浓度（C_b）、加速侵蚀浓度（C_a）和污染浓度（C_p）。其中Ｃ_a、Ｃ_b是由于自然因素造成的，Ｃ_p是由于人为活动直接造成的。同时，该方法还根据迁移方式将重金属分为2类，即A类金属（Zn和Cd）以溶解态迁移，与粘土矿物含量无关；B类金属（Fe，Ni，Cu和Pb）主要吸附在颗粒物上迁移，与粘土矿物元素（Mg）有极好的相关性。因此，应用Mg与B类金属的浓度之间的相关性，可推算出B类金属的C_b）和C_a）两部分浓度。ERA方法的不足之处是，它仅仅指出了重金属污染的相对程度，而不能确定污染级别。本论文结合国际水质标准提出了以ERA为标准的污染级别指数。改进后的ERA方法既可用于地区间重金属污染绝对量的横向比较，又可指出污染的级别。

关键词: 沉积物, 重金属, 污染, 太子河, 回归过量分析