论文总字数：38708字

摘 要

本文以太湖竺山湾地区殷村港、社渎港、漕桥河和太滆运河四条河流底泥为研究对象，对两年内的底泥中Cr⁶ 、Cu、Pb、Cd、As和Hg六种重金属和底泥中的有机质、底泥浸出液的总氮和总磷进行系统的分析，在此基础上，采用污染负荷指数法、潜在风险指数法、地累积指数法、沉积物质量标准法（SQG）4种方法对太湖竺山湾地区的底泥重金属上进行生态风险评估，利用比较法对底泥营养盐进行生态风险评估，结果表明：

（1）Cu和Pb随时间的变化幅度比较大，在不同区域的差异性比较大；Cr6 、Cd、As和Hg随时间的变化不明显，在竺山湾地区分布相对比较均匀。底泥营养盐也呈现类似的特征。

（2）除Cr⁶ 之外，其他重金属都明显高于各自的背景值，说明随着该地区的城镇化、工业化发展，底泥中重金属也明显富集。与相关标准相比，该地区重金属呈现不同程度的污染。底泥浸出液中总磷处于Ⅴ类水平，总氮处与劣Ⅴ类水平，污染比较严重。

（3）六种重金属中，Cu元素和Cd元素的污染最为严重。Cu、Cd、Hg的平均浓度超过ERL水平，可能造成生物毒害效应；对太湖竺山湾底泥重金属污染贡献较大，并存在潜在生态风险。竺山湾地区I_pLzone指数为3.19，污染负荷程度非常高，属于极强程度；RI指数为强，具有高潜在生态风险。As的平均浓度超过ERL水平，可能造成生物毒害效应。在竺山湾地区，Cu、Cd和Hg是优先控制的重金属元素，应加以重视。底泥浸出液氮磷比大部分大于7.2 ，磷含量是藻类增长的限制因素，因此磷是污染控制重点。

关键词：底泥；重金属；营养盐；生态风险评估

Ecological Risk Assessment of Taihu Zhushan Bay’s Sediment Pollution

Abstract

We researched Taihu Zhushan Bay’s four river，Yincun River，Shedu River, Caoqiao River and Taige River’sediment for two years, and we analyzed Cr⁶ , Cu, Pb, Cd, As and Hg, sediment organic matter and sediment leachate TN and TP systematic . On this basis, I used four motheds ,namely, pollution load index, the potential risk index, accumulate index, and sediment quality standards act (SQG) to assess ecological risk of Taihu Zhushan Bay area’s sediment. Besides, I assessed sediment nutrients ecological risk assessment by comparison. The results showed that：

(1) Cu and Pb changed in amplitude over time was relatively large, and had a large difference in the different regions; Cr⁶ , Cd, As and Hg had no significant changes over time, their concentration in Zhushan Bay’s area was relatively average. Sediment nutrients also showed similar characteristics。

(2) Except Cr⁶ ，other heavy metals were significantly higher than their background values, indicating that as the region’s urbanization and industrialization development, heavy metals significantly enriched in sediment. Compared with the relevant standards, heavy metals showed varying degrees of pollution. Total phosphorus in sediment leaching reached Ⅴ class level, TN at the inferior Ⅴ class level, obvioudly, pollution was serious.

(3) In six kinds of heavy metals，the most serious pollution of heavy metal were Cu elements and Cd elements. The average concentration of Cu, Cd and Hg exceed ERL and could cause biological toxic effects; they had a large contribution to heavy metals pollution in sediment of Zhushan Bay of Taihu Lake, in addition, they had a potential ecological risk. Zhushan Bay area’s I_pLzone index was 3.19, the degree of pollution load was very high, belonging to the strong degree. RI index was strong, with a high potential ecological risk. The average concentration of As exceeded ERL and could cause biological toxic effects. Cu, Cd and Hg were in priority control in Zhushan Bay area, attention should be paid. Sediment leaching Nitrogen to phosphorus ratio was larger than 7.2, and the phosphorus content was a limiting factor of algae growth.

Keywords：sediment; heavy metal; nutrients ; ecological risk assessment;

目录

摘要 3

Abstract 4

第一章 绪论 1

1.1河流湖泊底泥重金属及其他污染物简介 1

1.2太湖地区底泥污染研究进展 1

1.3底泥重金属及营养盐生态风险评估方法 3

第二章 材料和方法 5

2.1调查区域及采样点 5

2.2 样品处理及分析 7

第三章 太湖竺山湾地区底泥各化学指标含量 8

3.1 研究区底泥中各种化学指标的年变化与含量分析 8

3.2研究区底泥中各化学指标的平均含量分析 14

3.2.1研究区底泥中重金属的含量分析 14

3.2.2研究区底泥有营养盐的含量分析。 16

3.3研究区底泥的污染水平分析 17

3.3.1研究区底泥重金属污染水平分析 17

3.3.2底泥中营养盐污染水平分析 17

第四章 太湖竺山湾地区底泥生态风险评估 19

4.1 底泥重金属潜在生态危险评估 19

4.1.1污染负荷指数法 19

4.1.2潜在生态风险指数法 21

4.1.3地累积指数评价方法 23

4.1.4基于沉积物质量标准（SQG）法 28

4.2底泥中营养盐的生态风险评估 29

第五章 结论及建议 31

致谢 32

参考文献（References）： 33

第一章 绪论

1.1河流湖泊底泥重金属及其他污染物简介

底泥是各种污染物的储备库，能接纳吸收污染物，也能释放污染物，造成二次污染。沉积物是非常复杂的非均质体，其中含有的具有不同形态等的重金属，这些重金属的生物有效性、毒性及它们的迁移循环可能会产生不同的环境效应^[1]。水体沉积物重金属含量与沉积物中有机质含量、氧化还原条件和粒径组成有关。

底泥中的重金属主要包括Cu、Pb、Zn、Cd、Hg、As和Ni等及其化合物。主要来源于矿山开采的含重金属废水、冶炼厂的排污废水、城市工业污废水和生活污水、水土流失和农业化肥农业施用、水面穿船舶运输等^[2]。

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