石河子地区土壤中微量汞形态分析及其环境评价
发布时间：2018-08-14 11:40
【摘要】：汞,一种极具生物毒性的微量元素,能对环境造成长久性的污染危害。汞污染对环境的影响自日本水俣病以来已经引起极大关注。随着西部大开发不断推进,一批高污染、高耗能企业落户“戈壁明珠”绿洲石河子市。然而,有关氯碱生产和燃煤发电集中地区汞污染的基础研究尚处于缺乏阶段,亟需针对该地区土壤进行汞污染特征分布的研究,旨在为该地区土壤汞环境防治提供依据。本文以氯碱化工和燃煤电厂集中的石河子为研究对象,研究土壤汞含量分布特征、形态汞特征分布、三种典型土壤对汞的吸附解吸特征以及土壤汞污染环境质量评价。主要研究结论如下:研究区石河子市区汞含量范围为0.001-0.902 mg·kg-1,平均值为0.176 mg·kg-1,远高于新疆背景值(0.017 mg·kg-1),但低于国家二级标准(1.000 mg·kg-1)。同时,还对石河子周边的沙湾地区和玛纳斯地区进行了土壤汞含量监测。沙湾地区土壤汞含量范围为0.001-0.491 mg·kg-1,平均值为0.102 mg·kg-1;玛纳斯地区土壤汞含量在0.046-0.882 mg·kg-1之间,平均值为0.286 mg·kg-1,高于石河子土壤平均汞含量;生物可利用性分析知,石河子地区土壤样中能被动植物利用的形态汞较少,但对生物具有较大的潜在生物可利用性;土壤汞形态相关性分析发现,随土壤总汞含量增加,其易溶性有机质结合态、难溶性有机质结合态汞和残渣态汞含量也会增加;有机质与易溶性有机质结合态、难溶性有机质结合态汞和残渣态汞的含量均表现出显著的正相关性。市区三种典型土壤汞的最大吸附量表现为:草甸土最大,潮土次之,灰漠土最小;最大解吸量顺序和最大吸附量顺序一致。有机质对汞吸附解吸的影响实验表明,土壤环境中有机物含量越低,土壤中汞的解吸反应越易发生。土壤吸附动力学实验表明,潮土吸附速率最大,草甸土吸附速率次之,灰漠土吸附速率最小。土壤及其与汞络合物的FTIR光谱试验表明,吸附主要发生在O-H,C-O和C=O或C=N基团。市区土壤微量汞环境风险评价表明:市区土壤汞释放量变化甚微,对市区整体环境质量影响不大。石河子市区总体上表现为非污染或轻度污染,符合国家土壤环境标准;土壤汞通过三种途径(摄食、皮肤接触、呼吸接触)给人体带来的健康风险均在安全范围以内。
[Abstract]:Mercury, a highly biotoxic trace element, can cause long-term pollution hazards to the environment. The environmental impact of mercury pollution has attracted much attention since Minamata disease in Japan. With the great development of the western region, a group of high pollution and energy consuming enterprises have settled in Shihezi City, the Gobi Pearl Oasis. However, the basic research on mercury pollution in chlor-alkali production and coal-fired concentrated power generation areas is still in the lack of stage. It is urgent to study the distribution of mercury pollution characteristics in soil in this area, in order to provide the basis for soil mercury environmental control in this area. Taking Shihezi concentrated in chlor-alkali chemical industry and coal-fired power plant as the research object, this paper studies the distribution characteristics of mercury content in soil, the distribution of mercury speciation, the adsorption and desorption characteristics of mercury in three typical soils and the environmental quality evaluation of mercury pollution in soil. The main conclusions are as follows: the range of mercury content in Shihezi urban area is 0.001-0.902 mg kg-1, with an average of 0.176 mg kg-1, which is much higher than the background value of Xinjiang (0.017 mg kg-1), but lower than the national second class standard (1.000 mg kg-1). At the same time, soil mercury content was monitored in Shawan area and Manas area around Shihezi. The range of soil mercury content in Shawan is 0.001-0.491 mg / kg ~ (-1), the average value is 0.102 mg / kg ~ (-1), and that in Manas area is 0.046 ~ 0.882 mg / kg-1, the average value is 0.286 mg / kg ~ (-1), which is higher than that in Shihezi soil. In Shihezi area, the species of mercury that can be utilized by plants and animals are less, but they have great potential bioavailability to organisms, and the correlation analysis of soil mercury forms shows that, with the increase of total mercury content in soil, its soluble organic matter is bound to form. The contents of insoluble organic matter bound mercury and residual mercury also increased, and the contents of organic matter and easily soluble organic matter, insoluble organic matter bound mercury and residue mercury showed significant positive correlation. The maximum amount of mercury adsorbed by three typical soils in urban area was the largest in meadow soil, the second in tidal soil and the smallest in grey desert soil, and the sequence of maximum desorption and maximum adsorption was the same. The effect of organic matter on the adsorption and desorption of mercury showed that the lower the content of organic matter in soil, the easier the desorption reaction of mercury in soil. The adsorption kinetics experiments showed that the adsorption rate was the highest in the fluvo-soil, the second in the meadow soil and the lowest in the grey desert soil. The FTIR spectra of the soil and its mercuric complexes show that the adsorption occurs mainly in O-HG C-O and Con O or Con N groups. The environmental risk assessment of trace mercury in urban soil shows that there is little change in mercury release from soil in urban area, which has little effect on the overall environmental quality of urban area. The urban area of Shihezi is not polluted or slightly polluted, which accords with the national standard of soil environment, and the health risk caused by mercury in soil through three ways (feeding, skin contact, respiratory contact) is all within the safe range.
【学位授予单位】：石河子大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X833;X825
[Abstract]:Mercury, a highly biotoxic trace element, can cause long-term pollution hazards to the environment. The environmental impact of mercury pollution has attracted much attention since Minamata disease in Japan. With the great development of the western region, a group of high pollution and energy consuming enterprises have settled in Shihezi City, the Gobi Pearl Oasis. However, the basic research on mercury pollution in chlor-alkali production and coal-fired concentrated power generation areas is still in the lack of stage. It is urgent to study the distribution of mercury pollution characteristics in soil in this area, in order to provide the basis for soil mercury environmental control in this area. Taking Shihezi concentrated in chlor-alkali chemical industry and coal-fired power plant as the research object, this paper studies the distribution characteristics of mercury content in soil, the distribution of mercury speciation, the adsorption and desorption characteristics of mercury in three typical soils and the environmental quality evaluation of mercury pollution in soil. The main conclusions are as follows: the range of mercury content in Shihezi urban area is 0.001-0.902 mg kg-1, with an average of 0.176 mg kg-1, which is much higher than the background value of Xinjiang (0.017 mg kg-1), but lower than the national second class standard (1.000 mg kg-1). At the same time, soil mercury content was monitored in Shawan area and Manas area around Shihezi. The range of soil mercury content in Shawan is 0.001-0.491 mg / kg ~ (-1), the average value is 0.102 mg / kg ~ (-1), and that in Manas area is 0.046 ~ 0.882 mg / kg-1, the average value is 0.286 mg / kg ~ (-1), which is higher than that in Shihezi soil. In Shihezi area, the species of mercury that can be utilized by plants and animals are less, but they have great potential bioavailability to organisms, and the correlation analysis of soil mercury forms shows that, with the increase of total mercury content in soil, its soluble organic matter is bound to form. The contents of insoluble organic matter bound mercury and residual mercury also increased, and the contents of organic matter and easily soluble organic matter, insoluble organic matter bound mercury and residue mercury showed significant positive correlation. The maximum amount of mercury adsorbed by three typical soils in urban area was the largest in meadow soil, the second in tidal soil and the smallest in grey desert soil, and the sequence of maximum desorption and maximum adsorption was the same. The effect of organic matter on the adsorption and desorption of mercury showed that the lower the content of organic matter in soil, the easier the desorption reaction of mercury in soil. The adsorption kinetics experiments showed that the adsorption rate was the highest in the fluvo-soil, the second in the meadow soil and the lowest in the grey desert soil. The FTIR spectra of the soil and its mercuric complexes show that the adsorption occurs mainly in O-HG C-O and Con O or Con N groups. The environmental risk assessment of trace mercury in urban soil shows that there is little change in mercury release from soil in urban area, which has little effect on the overall environmental quality of urban area. The urban area of Shihezi is not polluted or slightly polluted, which accords with the national standard of soil environment, and the health risk caused by mercury in soil through three ways (feeding, skin contact, respiratory contact) is all within the safe range.
【学位授予单位】：石河子大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X833;X825
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