【作者】 刘慧力；

【导师】 崔龙鹏；

【作者基本信息】 安徽理工大学 ， 环境工程， 2009， 硕士

【摘要】 沉积物作为水环境中金属元素的主要蓄积库,可以反映水体受金属污染的状况。随着淮南市“煤电化三大基地”的建设,大量的固体废物堆置在地表,在风化、淋溶作用下,有害金属元素将会释放,并迁移到周围的土壤和地表水体中,对矿区的生态环境造成了一定的危害。本文通过对矿区沉陷水体及灰场周边水体的表层沉积物进行研究,从总量上分析水体沉积物中金属元素的分布、富集特征;通过科学的评价,揭示受煤电工业影响的水体金属污染状况,预测金属元素对水环境的生态风险,同时对金属元素的迁移性规律进行研究。结果如下:1、矿区沉陷水体沉积物中,元素Cd的危害程度较其他金属严重。矿井区的生态危害程度为:报废矿井区＞老矿井区＞新矿井区。开采时间越长,煤矸石风化、淋溶的程度就越高,金属对矿区造成的生态危害就越大。2、淮南三大灰场周边水体沉积物中,金属cd的生态危害最为严重。各灰场周边水体受金属元素危害的程度为:上窑采样区＞高皇采样区＞新集采样区。淮南粉煤灰中金属含量以残渣态为主,灰中金属向环境迁移的量很小,但是长久堆置,粉煤灰中金属元素可溶出态的比例会越来越大。pH值对灰场土壤中Cd元素形态含量及其迁移影响很大,是沉积环境中Cd元素富集的重要因素。3、田集示范区沉陷水体上覆水中元素Cu的含量超出渔业水质标准;元素Hg的含量超出地表水环境质量标准。表层沉积物中Cu和zn的含量相对较高。通过金属相关性分析可知,表层沉积物中As、Cr和cu可能有相同的污染来源;Hg、Pb、Cd和Zn也可能有相同的污染来源。表层沉积物金属主要以残渣态为主,对水体造成二次污染的可能性较小。通过评价可知元素Cd的危害最大。因风刮及降水沉降的影响,致使大量的煤矸石及煤颗粒涵盖于矿区周边土壤中,导致项目区沉陷地土壤中的金属含量略高于灰场土壤。本文对水体环境金属污染的调查可知,整个淮南矿区沉陷水体及灰场周边水体沉积环境的生态风险为轻微级,属安全等级。更多还原

【Abstract】 As the accumulation place of metals in the water environment, sediments can reflect the situation about how metals pollute waters. With the development of the three bases of coal mines, power plants and chemical factories in Huainan, lots of solid wastes were stacked on the ground surface. Because of the effect of weathering and leaching, hazardous metal elements among solid wastes will release and transfer into surrounding soils and surface waters, snd they will damage the ecological environment of the mining area. Through studying on the surface sediment of subsidence-waters in the mine area and waters around the ash field, this paper analyzes the characteristics of metal distribution and enrichment by measuring the total amount, and reveals the situation of water pollution by metals under the influence of the development of coal mines and power plants through the scientific evaluation, predicts the ecological risk on the water quality caused by metals, meanwhile, studies the mobility law of metal elements. The results show that:1、According to the sediments of subsidence waters in the mining areas, the damage degree of Cd is larger than other metal elements’. The order of degrees in which the ecology is harmed in the study area is, abandoned mining areas’ > old mining areas’ > new mining areas’. The longer the time of the exploitation is, the higher the degree of weathering and leaching of coal gangue rises, and the more serious the potential ecological risk caused by metals becomes in the mining area.2、Through the assays of waters sediments in the three major ash fields in Huainan, the damage from Cd is the most serious. The order of harm-to-ecology degrees of the study areas is Shangyao sampling area’s > Gaohuang sampling area’s > Xinji sampling area’s. The morphology of metals in the coal fly ash is mainly the residual state and the amount of metals in the coal fly ash transferring to the environment is very small. However, as the stacking time passes, the proportion of soluble stated metals in the coal fly ash will get bigger and bigger. pH obviously influences the morphological concentration of Cd in soils surrounding the ash field, it is an important factor for Cd to enrich in sedimentary environment.3、The concentration of Cu in the overlying level of subsidence waters in Tianji exceeds the corresponding one of environmental quality standards for fishery water , the concentration of Hg exceeds the corresponding one of environmental quality standards for surface water . The concentration of Cu and Zn in the superficial sediment is relatively higher. Through the analysis of metal correlation, it is found that As, Cr and Cu in the superficial sediment maybe come from the same pollution source, and Hg, Pb, Cd and Zn maybe also get out of the same pollution source. The morphology of metals in the superficial sediment of project area is mainly the residual state, the possibility of a secondary water pollution caused by metals is smaller.It is found that the damage caused by Cd is the most serious by evaluation. Under the brush of wind and rain lots of particles drop off the coal gangue and the coal and cover on the soil near the mining area, which causes that the metals concentrations in soils of the coal mining subsidence land of the project are a little higher than those in soils of the ash field of Tianji power plant.Through the investigation on metal pollution of water environment, it is found that the ecological risk of sedimentary environment of the all subsidence waters and waters around the ash field is of a slight and safe grade.更多还原