【作者】 杨苏才；

【导师】 南忠仁；

【作者基本信息】 兰州大学 ， 环境科学， 2006， 硕士

【摘要】 重金属的生物霉性不仅取决于其总量,更大程度上是受其存在形态的影响,不同的形态产生不同的环境效应。因此,研究土壤重金属形态分布规律和影响因素是非常有意义的。本论文以张掖市绿洲土壤为研究对象,利用土培实验和Tessier连续提取法研究了外源可溶性重金属锌、镉、镍、铅加入土壤后土壤重金属形态分布与变化趋势。研究结果表明: ① 在原状土壤中,锌各个形态的分配系数按以下顺序递减:残渣态锌>铁锰氧化物结合态锌>有机结合态锌>碳酸盐结合态锌>可交换态锌;镉各个形态的分配系数按以下顺序递减:残渣态镉>碳酸盐结合态镉>铁锰氧化物结合态镉>有机结合态镉>可交换态镉;镍各个形态的分配系数按以下顺序递减:残渣态镍>有机结合态镍>铁锰氧化物结合态镍>碳酸盐结合态镍>可交换态镍;铅各个形态的分配系数按以下顺序递减:残渣态铅>铁锰氧化物结合态铅>有机结合态铅>碳酸盐结合态铅≈可交换态铅。总之,原状土壤中锌、铅、镍主要以残渣态形式存在;尽管镉也主要以残渣态形式存在,但残渣态镉的分配系数要比残渣态锌、铅、镍的分配系数低很多,镉主要以残渣态、碳酸盐结合态和铁锰氧化物结合态形式存在。 ② 在实验土壤中,锌各个形态的分配系数按以下顺序递减:铁锰氧化物结合态锌>碳酸盐结合态锌>残渣态锌>有机结合态锌>可交换态锌;镉各个形态的分配系数按以下顺序递减:碳酸盐结合态镉>铁锰氧化物结合态镉>可交换态镉>有机结合态镉>残渣态的镉;镍各个形态的分配系数按以下顺序递减:铁锰氧化物结合态镍>碳酸盐结合态镍>有机结合态镍>残渣态镍>可交换态镍;铅各个形态的分配系数按以下顺序递减:碳酸盐结合态铅>铁锰氧化物结合态铅>残渣态的铅>可交换态铅>有机结合态铅。总之,实验土壤中锌、铅、镉主要以碳酸盐结合态和铁锰氧化物结合态的形式存在;镍主要以碳酸盐结合态、铁锰氧化物结合态和有机结合态的形式存在。 ③ 随着实验土壤中镉、锌、镍、铅负荷的增加,镉、锌、镍、铅的可交换态、碳酸盐结合态、铁锰氧化物结合态、有机物结合态以及残渣态的含量均呈现增加态势。进一步分析知,残渣态镉、锌、镍、铅增长态势不明显;可交换态镉、锌、镍、铅和有机结合态镉、锌、镍、铅增长态势均较为明显;碳酸盐结合态和铁锰氧化物结合态的镉、锌、镍、铅增长态势极为明显。 ④ 随着实验土壤中镉、锌、镍、铅负荷的增加,残渣态镉、锌、镍、铅的分配系数均呈现显著的下降态势;有机结合态镉、锌、镍、铅变化趋势不明显或略有下降;可交换态锌、铅呈现极显著的增加态势,可交换态镉增加趋势不明显,可交换态镍先增大后减小;碳酸盐结合态锌、铅呈现极显著的增加态势,碳酸盐更多还原

【Abstract】 The problem of the heavy metal pollution of soil bring broad attention from the environmental researcher. However, the biology toxicity of heavy metal not only lies on its gross contents, but also are influenced by its speciation distribution largely and different speciation bring different environmental effect. So, the research of the distribution rule and effect factors of the speciation of soil heavy metal is very significant.in this paper,we used field and pot experiments and Tessier A sequential extraction method to study the speciation distributions and effect factors of Cd, Pb, Ni, Zn in oasis soil.The experiment results indicates that in oasis soils, distribution coefficient of RES-Zn> distribution coefficient of Fe-Mn-Zn> distribution coefficient of OM-Zn> distribution coefficient of CA-Zn>distribution coefficient of EXC-Zn;distribution coefficient of RES-Cd > distribution coefficient of CA-Cd>distribution coefficient of Fe-Mn-Cd > distribution coefficient of OM-Cd > distribution coefficient of EXC-Cd;distribution coefficient of RES-Ni> distribution coefficient of OM-Ni> distribution coefficient of Fe-Mn-Ni>distribution coefficient of CA-Ni> distribution coefficient of EXC-Ni;distribution coefficient of RES-Pb>distribution coefficient of Fe-Mn-Pb > distribution coefficient of OM-Pb > distribution coefficient of CA-Pb" distribution coefficient of EXC-Pb.in a word,Zn,Cd,Ni,Pb is mainly in residual fraction in oasis soils;though Cd is also mainly in residual fraction,the distribution coefficient of Cd is lower than the distribution coefficient of Zn, Ni,Pb in oasis soils.Cd is mainly in residual fraction, carbonate fraction and Fe-Mn oxides fraction in oasis soils.In experimental soils, distribution coefficient of Fe-Mn-Zn > distribution coefficient of CA-Zn> distribution coefficient of RES-Zn> distribution coefficient of OM-Zn> distribution coefficient of EXC-Zn;distribution coefficient of CA-Cd> distribution coefficient of Fe-Mn-Cd > distribution coefficient of EXC-Cd > distribution coefficient of OM-Cd > distribution coefficient of RES-Cd;distribution coefficient of Fe-Mn-Ni> distribution coefficient of CA-Ni> distribution coefficient of OM-Ni>distribution coefficient of RES-Ni> distribution coefficient of EXC-Ni;distribution coefficient of Fe-Mn-Pb > distribution coefficient of CA-Pb > distribution coefficient of RES-Pb> distribution coefficient of OM-Pb > distribution coefficient of EXC-Pb.in a word,Zn,Pb,Cd is mainly in carbonate fraction and Fe-Mn oxides fraction;Ni is mainly in carbonate fraction , Fe-Mn oxides fraction and organic fraction.With the increase of the contents of Zn,Cd,Ni,Pb in oasis experimental soils, thecontents of Zn,Cd,Ni,Pb of exchangeable fraction, carbonate fraction, Fe-Mn oxides fraction, and organic fraction increased obviously, the contents of Zn,Cd,Ni,Pb of residual fraction increased unobviously;the contents of Zn,Cd,Ni,Pb of exchangeable fraction,and organic fraction increased obviously;the contents of Zn,Cd,Ni,Pb of carbonate fraction and Fe-Mn oxides fraction increased extremely obviously.With the increase of the contents of Zn,Cd,Ni,Pb in oasis experimental soils, the distribution coefficient of Zn,Cd,Ni,Pb of residual fraction decreased obviously;the distribution coefficient of Zn,Cd,Ni,Pb of organic fraction decreased obviously or decreased;the distribution coefficient of Zn, Pb of exchangeable fraction increased obviously,the distribution coefficient of Cd of exchangeable fraction increased unobviously,the distribution coefficient of Ni of exchangeable fraction increased obviously at first,then decreased;the distribution coefficient of Zn, Pb of carbonate fraction increased obviously, the distribution coefficient of Ni of carbonate fraction increased obviously at first and then increased unobviously, the distribution coefficient of Cd of carbonate fraction increased obviously at first and then increased unobviously,the distribution coefficient of Cd of carbonate fraction might decreased at last;the distribution coefficient of Cd,Pb,Zn of Fe-Mn oxides fraction increased obviously at first and then decreased obviously,the distribution coefficient of Ni of Fe-Mn oxides fraction increased obviously.更多还原