长期以来工业“三废”几乎对我国所有环境要素产生了负面影响，地表水体是其中一个污染物接纳体。重金属污染物进入水体后，绝大多数重金属会逐渐转移至底泥中，并在底泥中富集。其中，采矿以及冶炼区河流底泥中重金属的蓄积情况更为严重。因此，本研究就金矿区重金属污染底泥为研究对象，开展了两方面的研究工作：第一，调查金矿区界河流域底泥重金属空间分布和赋存形态，对富集于底泥的重金属溯源分析，并运用多种评价方法对底泥重金属进行风险评估，全面了解金矿区河流底泥重金属污染特征；第二，针对两种工程应用广泛的重金属污染底泥处理处置技术——土工管袋自然脱水填埋处置技术和高效脱水减容填埋处置技术，探究底泥处置场地的环境友好性，跟踪分析底泥经两种工程处理后的环境危害性，揭示处理底泥重金属的稳定性。主要得出以下结论：

1）界河流域底泥重金属污染特征：由于过去数十年的采矿、炼金和施用农药及化肥等工农业活动的影响，界河沉积物中As、Cd和Hg含量分别超出中国水系沉积物背景值622.2、329.8、16.5倍。在空间分布上，沉积物中重金属含量变异性极高。通过风险评估方法分析得出，Hg、Cd、As和Cu的潜在生态风险居于最高水平，对生物体具有巨大威胁。从健康风险评估结果来看，7种重金属（Cr、As、Cd、Hg、Pb、Cu和Zn）的非致癌性健康风险指数均小于1，说明界河底泥重金属的健康风险可以忽略。来源解析的结果说明沉积物重金属富集主要来源于金矿开采以及金属冶炼和农业生产活动。

2）评估两种填埋处置场地表层土重金属的环境风险：通过对土工管袋自然脱水处置填埋场地和高效脱水减容处置填埋场地表层土壤重金属含量和赋存形态测定，进而分别采用I_geo、RSP和人类健康风险评估3种环境风险评价方法分析得到：土工管袋自然脱水填埋场地表层土壤中Cd的生物有效态百分比高，生物可利用性高，对环境可能造成的有害效应较强；另外，As对附近居民的非致癌健康暴露不容忽视；高效脱水减容填埋场地表层土壤中As对儿童具有一定的健康风险，要防范该场地土壤对儿童的暴露风险。

3）评估两种底泥处理技术处置3年后底泥重金属的安全性：综合两种处置底泥重金属总量、赋存形态分布特征、浸出毒性检测结果和RAC、PERI评估结果得到：土工管袋自然脱水处置底泥重金属安全系数高，且不存在污染本地地下水的生态风险；高效脱水减容处置底泥该场地底泥中重金属对环境危害性较低，安全性较高，对区域生态影响能力有限，但应重视Ni渗滤的可能性。

数十年工业污染物的积累导致河流底泥重金属富集严重，生态危害性极强。重金属污染严重底泥经过异位固化稳定化处理填埋处置后，重金属生物有效性降低，生态风险减弱，迁移可能性和转移能力减小。处理底泥填埋场地重金属的环境风险不容忽视，填埋过程需确保覆土的清洁和安全。

For a long time, industrial "three wastes" have had a negative impact on almost environment in China. Surface water was one of the pollutant acceptors. After the heavy metal pollutants enter the water body, most of the heavy metals will gradually transfer to the sediment and enrich in the sediment. The accumulation of heavy metals in river sediment in mining and smelting areas was more serious. Therefore, this study taked the sediment polluted by heavy metals in gold mining area as the research object, and carried out two aspects of research work: 1) investigating the spatial distribution and forms of heavy metals in the Jiehe river of gold mining area, tracing the source of heavy metals enriched in sediment, and using various evaluation methods to carry out risk assessment of heavy metals, to comprehensively understand the characteristics of heavy metals pollution in river sediment of gold mining area; 2) Aiming at two kinds of treatment and disposal technologies of sediment contaminated by heavy metals widely used in engineering, i.e. geotechnical bag landfill technology and highly efficient dewatering landfill technology, the environmental friendliness of sediment in disposal site was ensured, the environmental hazards of sediment treated by two kinds of projects were tracked and analyzed, the stability of heavy metals in sediment was revealed.

The main conclusions are as follows:

1) Characteristics of heavy metal pollution in the sediment of Jiehe River: As, Cd and Hg contents in the sediment of Jiehe River exceeded the background values of Chinese river sediments by 622.2, 329.8 and 16.5 times, respectively. The variability of heavy metals in sediments was very high in spatial distribution. The potential ecological risks of Hg, Cd, As and Cu were at the highest level and posed a great threat to organisms. According to the results of health risk assessment, the non-carcinogenic health risk index of seven heavy metals (Cr, As, Cd, Hg, Pb, Cu and Zn) was less than 1, which indicated that the health risk of heavy metals in the sediment of Jiehe River can be neglected. The results of source analysis showed that the accumulation of heavy metals in sediments mainly came from gold mining, metal smelting and agricultural activities.

2) Assessing the environmental risk of heavy metals in surface soil of two landfill disposal sites: Determining of heavy metals contents and forms in surface soil of geobag national dewatering landfill site and high-efficiency dewatering landfill site, and three environmental risk assessment methods, I_geo, RSP and human health risk assessment were used respectively. The results showed that the bio-availability percentage of Cd in surface soil of geobag natural dewatering landfill site was high. In addition, the non-carcinogenic health exposure of As to nearby residents should not be neglected; As in surface soil of high-efficiency dewatering landfill site had certain health risks to children, so it is necessary to guard against the exposure risk of the site soil to children.

3) Evaluating the safety of sediment after three years of landfill with two kinds of sediment treatment technologies: Based on the amount of heavy metals in sediment, distribution characteristics of metal forms, leaching toxicity test and RAC ,PERI evaluation results, it was concluded that the safety of sediment treated by geo-bags natural dewatering treatment was high, and there was no ecological risk of polluting local groundwater; the environmental hazard of heavy metals in sediment treating by high-efficiency dewatering treatment was low and the environmental influence ability was limited, but attention should be paid to the possible risk of Ni infiltration.

The production of industrial pollutants over the past decades has resulted in serious accumulation of heavy metals in river sediments, which was extremely serious ecological harm. After sediment contaminated by heavy metal was treated by heterotopic solidification and stabilization landfill, the bioavailability of heavy metals was reduced, the ecological risk was changed to weaken, and the migration possibility and transfer ability could be reduced. In addition, the health risk of heavy metals in landfill site should not be neglected, and it is necessary to ensure the cleanliness and safety of overburden soil in landfill site.

第1章 绪论... 1

1.1 底泥重金属污染... 1

1.1.1 重金属污染的定义... 1

1.1.2 河流底泥重金属污染... 1

1.1.3 底泥重金属污染的来源... 1

1.1.4 底泥重金属污染的特点... 3

1.1.5 底泥重金属形态相互转化过程... 4

1.1.6 底泥重金属迁移过程... 5

1.2 重金属生态风险评估方法... 6

1.2.1 基于重金属总量... 6

1.2.2 基于重金属形态... 6

1.2.3 基于生态健康风险... 7

1.3 底泥污染重金属治理技术... 7

1.3.1 物理方法... 7

1.3.2 化学方法... 8

1.3.3 生物方法... 8

1.3.4 其他方法... 9

1.4 处置底泥的安全性跟踪... 9

1.5 研究内容及意义... 10

1.5.1 立题依据及意义... 10

1.5.2 研究内容... 11

第2章 区域概况与研究方法... 12

2.1 研究区域介绍... 12

2.1.1 界河研究区域... 12

2.1.2 沂水沂河底泥处置示范工程介绍... 13

2.2 样品采集和测定... 15

2.2.1 界河沉积物采样及分析... 15

2.2.2 沂水沂河样品采集及分析... 15

2.3 底泥重金属浸出毒性... 16

2.4 沉积物重金属生态风险评价... 16

2.4.1 基于重金属总量... 16

2.4.2 基于重金属形态... 18

2.4.3 基于生态健康危害... 19

2.5 数据分析与质量控制... 23

第3章 底泥重金属污染特征及其生态风险评估... 24

3.1 引言... 24

3.2 结果与讨论... 24

3.2.1 底泥重金属含量及其分布... 24

3.2.2 底泥重金属污染程度评价... 29

3.2.3 底泥重金属环境风险评价... 29

3.2.4 底泥重金属健康风险评价... 33

3.2.5 底泥重金属来源分析... 34

3.3 结论... 37

第4章 不同填埋方式场地重金属环境风险评估... 38

4.1 引言... 38

4.2 土工管袋自然脱水底泥填埋处置场地... 38

4.2.1 场地表层土重金属总量... 38

4.2.2 场地表层土重金属形态分析... 39

4.2.3 场地表层土重金属环境风险评价... 42

4.3 高效脱水减容底泥填埋处置场地... 44

4.3.1 场地表层土重金属总量... 44

4.3.2 场地表层土重金属形态分布... 45

4.3.3 场地表层土重金属环境风险评价... 47

4.4 结论... 49

第5章 不同处理方式底泥重金属安全性评估... 51

5.1 引言... 51

5.2 土工管袋自然脱水底泥填埋处置技术... 52

5.2.1 处置底泥重金属总量... 52

5.2.2 处置底泥重金属浸出毒性... 53

5.2.3 处置底泥重金属形态分布... 54

5.2.4 处置底泥重金属生态风险评价... 56

5.3 高效脱水减容底泥填埋处置技术... 57

5.3.1 处置底泥重金属总量... 57

5.3.2 处置底泥重金属浸出毒性... 58

5.3.3 处置底泥重金属形态分布... 59

5.3.4 处置底泥重金属生态风险评价... 61

5.4 结论... 62

第6章 总结与展望... 64

6.1 总结... 64

6.2 创新点... 65

6.3 展望... 65

参考文献... 67

致 谢... 85

作者简历及攻读学位期间发表的学术论文与研究成果... 87