【作者】 杜烨锋；

【导师】 李取生；

【作者基本信息】 暨南大学 ， 环境工程， 2009， 硕士

【摘要】 以珠江口滩涂土壤为研究对象,通过淋洗实验,对不同脱盐阶段、不同深度的孔隙水重金属含量和土壤重金属含量以及土壤氧化还原电位、孔隙水pH值等理化性质进行分析,研究了重金属在脱盐过程中的垂直迁移状况,以期为重金属污染滩涂土壤的修复与安全利用提供理论依据。结果表明:随着土柱深度的增加,土壤还原性增强,水分减少。土壤盐分随土柱深度增加而明显增大。对于同层土壤,孔隙水电导率在淋洗脱盐过程中有逐步减小的趋势。淋洗脱盐过程中,孔隙水重金属Cd、Pb和Cr含量随着深度增加而有增大趋势;水溶性Zn和Cu浓度在淋洗初期下降速度较快,在淋洗到一定程度时土柱各层含量保持相对稳定,Ni未检出。土柱孔隙水中Cd、Cr、Pb、Cu和Zn元素的总平均浓度都随着淋洗过程呈下降趋势。淋洗脱盐过程促进了表层土壤重金属向下迁移。由于迁移速度和形态转化等方面的差异,在脱盐过程中各种重金属表现出不同的累积特点。从土壤重金属的土柱总平均浓度来看,除Ni浓度基本不变外,土壤中Cd、Pb、Cr、Zn和Cu含量都随土壤盐分降低呈现总体下降趋势。从淋洗程度来看,Cd和Pb浓度降低幅度最大;Zn、Cu和Cr次之,Ni最小。同一盐分梯度土壤Cd、Zn和Pb含量随深度增加而增加,而Cr、Cu和Ni的上下层含量变化不明显。更多还原

【Abstract】 Based on the tidal flat soil in the Pearl River estuary,the heavy metal concentrations and soil physical and chemical properties such as Eh,pH of pore water and moisture content in different stages of desalination and vertical depths were investigated through leaching experiment.The vertical movement of heavy metals during leaching was studied,so as to provide a theoretical basis for the cleanup and safe use of the polluted tidal flat soil.The results showed that:With the increase in the depth of soil column,the reducibility of soil and salinity increased either,but the moisture content decreased. The conductivity of pore water decreased during leaching for the same soil layer.The concentrations of Cd,Pb and Cr in the pore water increased with the increase in the depth of soil column.Water-soluble Zn and Cu concentrations decreased rapidly in the beginning of leaching.Then they remained relatively stable.Ni wasn’t detected.The total average concentrations of Cd,Pb and Cr in the pore water decreased with the decrease of salinity in surface soils.Leaching desalination promotes the downward movements of heavy metals in surface soils during reclamation.The heavy metals accumulation in soil showed different characteristics during the leaching desalination.Study from the total average concentration of heavy metals of each treatment,the concentrations of Cd,Pb,Cr,Zn and Cu in soils increased with the increase in the depth of soil column.After leaching,the percentage of Cd and Pb concentration decrease was highest,followed by Zn,Cu and Cr,the percentage of Ni concentration decrease was minimum.更多还原