【作者】 鞠莉；

【导师】 张晓东； 冯素萍；

【作者基本信息】 山东大学 ， 环境科学， 2007， 硕士

【摘要】 本文以BCR连续分级提取法为基础，以沉积物标准样GBW07310和南水北调东线沿线南四湖、东平湖和梁济运河沉积物样品为研究对象，验证了可将有机结合态重金属和硫化物结合态重金属分级提取的四级五步连续分级提取法对实际沉积物样品的普适性，得出沉积物样品中不同形态重金属的含量；以模拟小麦、玉米、苹果、百羽扇豆、肥田萝卜、高麦草等六种植物根系分泌的低分子量有机混酸为提取剂，对沉积物样品分别进行单级提取及多级连续提取，将提取结果与沉积物样品中不同形态重金属的含量进行对比，以此来研究沉积物样品中重金属元素的生物有效性。实验所采用的四级五步连续分级提取法对南水北调东线沿线南四湖、东平湖和梁济运河九个采样点沉积物样品进行连续提取的结果表明，四级五步连续分级提取法的提取步骤合理，能够将沉积物样品中化学特性和毒理特点不同的有机结合态和硫化物结合态完全分离，而且四级五步连续分级提取法在改变了提取剂和提取步骤的情况下并没有引用较大的分析误差，对实际沉积物样品具有普适性。实验模拟植物根系分泌的有机混酸对沉积物样品进行提取的结果表明，一步提取能够提取沉积物中的可交换态、可还原态和有机结合态重金属，是最全面、最能反映植物分析分泌的有机酸对沉积物中重金属元素的活化吸收情况的提取步骤，因此其提取量能代表与该植物相关的重金属生物可利用量。在模拟植物根系分泌的有机混酸对沉积物样品中不同形态的重金属进行提取时，对可交换态的提取比例最大，对有机结合态的提取比例为其次，对可还原态的提取比例为最小，说明重金属可交换态是最易被生物活化的形态，有机结合态在其次，可还原态为最小。实验所模拟的六种植物根系分泌的有机混酸中，对同种重金属元素，以高麦草根系分泌的有机混酸的提取结果相对较大，以肥田萝卜根系分泌的有机混酸的提取结果相对较小。更多还原

【Abstract】 In this paper, GBW07310 and nine sediment samples were treated with BCR procedure and four-grade-five-step procedure with the intention to indicate the high accuracy of the four-grade-five-step procedure. And the concentrations of heavy metal of different fractions were got. At the same time, six mixed organic acids of low molecular weight which produced by plant roots were used to extract heavy metal in sediment samples with different extract procedures.The chemical and toxicological characteristic of heavy metals, which association with the organic matter and sulphide, is different. The two different speciations of heavy metals have different influences on the migration, conversion and toxicity of metals.The extract results that treated with GBW07301 and sediment samples indicated that the fraction of different biological availability could be separated; the pre-extraction of the fraction bound to the organic matter was eliminated. And so, the four-grade-five-step procedure could distinguish the metal speciation bound to organic matter from that to the sulphide completely on different sediment samples, showing the good adaptability on different locations.The extract results of mixed organic acids showed that the concentration of heavy metal extracted in one step contained exchengeable fraction, reducible fraction and oxidable fraction. Extracting in one step is the best extract procedure which could totally and exactly show the activate concentration and extract concentration of heavy metal in sediments by mixed organic acids. The concentration of heavy metal extracted by mixed organic acids in one step equals to the concentration of heavy metal that could be absorbed by plants.In the three fractions of heavy metal in sediment samples that extracted by mixed organic acids, the most extract percentage of heavy metal is exchengeable fraction , the second is oxidable fraction, and the least is reducible fraction. So we could conclude that the exchengeable fraction of heavy metal is the most easily activate and extract fraction absorbed by plants, oxidable fraction is the second, and reducible fraction is the least.In the six kinds of mixed organic acids simulated in the experiment, for the same heavy metal, the concentration extracted by mixed organic acids of grass’root is the largest, and the concentration extracted by mixed organic acids of radish’s root is the lowest.更多还原