【作者】 刘亚男；

【导师】 李取生；

【作者基本信息】 暨南大学 ， 环境工程， 2011， 硕士

【摘要】 本文以珠江口湿地滩涂土壤为研究对象,采用淋洗脱盐的方法研究阴阳离子共存的盐分变化对重金属化学形态、迁移转化及作物有效性的影响,以期为重金属污染的滩涂土壤的开发与利用提供科学依据。通过对珠江口湿地滩涂土壤的淋洗实验,对不同脱盐阶段,土壤孔隙水的盐分离子与土壤中各重金属含量及各重金属不同形态的含量进行监测与分析。结果表明,淋洗后较淋洗前各盐分离子的下降率分别为：Na+80.3%、K+73.5%、Mg2+ 86.6%、Ca2+90%、Cl-81.8%, SO42-98.2%,土壤孔隙水的pH值呈上升趋势；土壤中各重金属的下降率分别是Cd 26.6%、Pb 22.8%、Cu 16.9%、Cr 7.9%、Zn 9.1%,碳酸盐结合态的重金属下降率分别为：Pb 77.8%、Cr 61.7%、Cu 68.4%、Zn 67.1%、Cd 7.1%,铁锰氧化物结合态的Cd和Pb分别是49.1%和23.5%。淋洗脱盐过程改变了土壤重金属的化学形态、迁移状况。对淋洗之后含不同盐分的珠江口滩涂土壤进行土培实验,配制与其盐分、重金属含量相近的营养液进行水培实验,来研究淋洗脱盐对重金属作物有效性的影响。结果表明,土培实验中,苋菜根部Cd、Pb、Cr、Ni、Cu的含量>茎叶中的含量,淋洗脱盐能够抑制根部吸收重金属Cd、Pb、Cr、Cu,促进其吸收重金属Ni,能够抑制茎叶吸收Cd、Pb、Cu;在不同脱盐梯度下,苋菜茎叶对Zn的转运能力最强,对Cr的转运能力最弱。水培实验中不同盐分梯度下,苋菜体内Cd、Pb、Cr、Zn、Ni的分布规律也是根系部分>茎叶部分,Cu是茎叶部分>根系部分：营养液中盐分梯度下降能够抑制根系吸收Cd、Pb、Cr、Cu,促进对Zn的吸收,同时茎叶对Cd、Cu的吸收会下降,对Zn和Ni的吸收会增强；根系吸收不同重金属能力的大小顺序是Zn>Cd>Cu≈Ni>Cr>Pb,茎叶吸收重金属能力的大小顺序是Zn>Cu>Cd>Ni>Cr>Pb;茎叶转运不同重金属能力的大小顺序是Cu>Zn>Cd、Ni、Cr、Pb。更多还原

【Abstract】 In this paper, we collected the beach soil of Pearl River Estuary as our object, through out leaching method of desalination to investigate the influence of salt ions changes in the coexistence on changes of heavy metal speciation and the removal of heavy metals in the soil as well as heavy metal bioavailability, to provide effective foundation for the development and utilization of reclaimed tidal flats of the Pearl River Estuary, and the cultivation on saline and alkaline land.The salinity ion in soil pore water and the heavy metal content in soil as well as the heavy metal speciation were investigated in various stages of desalination during an experiment of leaching beach soil. Results show that salinity ion including Na+, K+, Mg2+, Ca2+, Cl- and SO42-decreased by 80.3%,73.5%,86.6%,90%,81.8%, 98.2% respectively compared to pre-leaching. The pH value of pore water increased with leaching time. The reductions of heavy metals after leaching were:Cd 26.6%, Pb 22.8%, Cu 16.9%, Cr 7.9%, Zn 9.1%. The concentrations of Pb, Cr, Cu, Zn and Cd in carbonate bound form decreased by 77.8%,61.7%,68.4%,67.1% and 7.1% respectively. The contents of Cd and Pb bound to Fe-Mn oxide decreased by 49.1%, 23.5% respectively. The procession of leaching desalination has influenced the chemical forms and migration status of heavy metal in soil.Through out the soil culture experiment of leaching Pearl River estuary beach soil with different salt, we prepared the nutrient solution with the salt and heavy metals closed to which in the soil culture experiment, to study the influence of leaching desalination on crops. The results showed:the salinity decreased was found to bate its uptake by the root of Common Amaranth for Cd、Pb、Cr、Cu and enhance its absorption ability for Ni.The absorption ability of Cd、Pb、Cu in the overground part of Common Amaranth has downtrend. The contents of Cd、Pb、Cr、Ni、Cu in the root of Common Amaranth> the contents of them in the overground part. The translocation abilities of Zn is strongest while to Cr is least. In the experiment of nutrient solution culture, the heavy metal distribution of Cd、Pb、Cr、Zn、Ni in Common Amaranth is the root> overground part in different contents of salinities, while Cu is overground part> the root. With the decreasing of the salinities in the nutrient solution, the contents of Cd、Pb、Cr、Cu have downtrend, but the Zn has uptrend in the overground part of Common Amaranth; the accumulation abilities of Cd、Cu were lower while to Zn、Ni was gather head in the overground part of Common Amaranth; The accumulation abilities of heavy metals in the root were Zn>Cd>Cu≈Ni>Cr>Pb in the root and Zn>Cu>Cd>Ni>Cr>Pb in the overground part of Common Amaranth. Translocation abilities of the overground part of Common Amaranth were Cu>Zn>Cd、Ni、Cr、Pb.更多还原