作 者 ：李冰1;王昌全1;代天飞1;3;李焕秀2;杨娟1
期 刊 ：植物营养与肥料学报 2007年 13卷 4期 页码：602-610
Keywords:heavy metal, rice, bioavailability, influence factors,
摘 要 ：在分析成都平原核心区土壤重金属(Cd、Cr、Pb、Cu、Zn)全量、各形态含量及相应点位种植的水稻子实重金属含量的基础上,通过统计分析、空间插值及线性回归方程的模拟,研究了土壤Cd、Cr、Pb、Cu、Zn全量的空间分布状况、各形态重金属含量统计特征,以及水稻子实对重金属各形态的累积差异及其影响因素。结果表明,成都平原水稻土重金属污染较轻,除Cd外,均低于国家土壤环境质量二级标准。土壤中重金属的可交换态含量均较低,Cd主要以铁锰氧化态存在,Cr、Cu、Zn、Pb主要以残渣态存在。水稻子实对5种重金属的累积效应顺序为:Cd>Zn>Cu>Pb>Cr。与水稻重金属累积关系密切的重金属活性形态(可交换态、碳酸盐结合态、铁锰氧化物结合态和有机物结合态)主要有:Cd的碳酸盐结合态、Cr的可交换态、Pb的有机物结合态和Cu的碳酸盐结合态含量;Zn各活性形态对水稻子实含量的影响不明显。土壤理化性质对不同活性形态重金属元素的影响效应各不相同。活性态Cd主要受有机质、pH和容重的影响;活性态Cr与pH、有机质、CEC和容重密切相关;活性态Pb与有机质、容重、中细粉粒、砂粒等均有密切的关系;Cu的活性主要受粘粒、有机质含量的影响;Zn的有效性主要受pH、有机质、砂粒、容重的影响。总的看来,对土壤Cd、Cr、Pb、Cu、Zn各活性形态含量影响效应较强的是有机质、pH、容重,而与土壤吸附性能密切相关的颗粒组成、CEC的影响不甚明显。
Abstract:The contents and speciation of heavy metals(Cd,Cr,Pb,Cu and Zn) in soils from the Chengdu Plain were analyzed and the contents of heavy metals in rice seeds from the same sampling sites were also determined.Statistical analyses including spatial interpolation and stepwise multiple linear regressions were used to determine the spatial distribution of these heavy metals and their speciation in the soils and to evaluate the relationship between heavy metal speciation in soil and bioaccumulation in rice seeds.The results indicated that the soil pollution is not significant in these sites since the heavy metal contents were lower than the level II criteria of the national environmental quality standard for soils except for Cd.The content of exchangeable fractions was low for all heavy metals studied.Heavy metals Cr,Cu,Zn and Pb were mainly found in the residual fractions,and Cd was mainly bound with Fe-Mn oxides.The accumulation sequence of heavy metals in rice seeds was: Cd>Zn>Cu>Pb>Cr.The labile fractions(exchangeable,carbonate bound,Fe-Mn oxides bound,organic matter bound) in soils which had good correlations with the heavy metal accumulation in rice seeds were carbonate bound Cd,exchangeable Cr,organic matter bound Pb,and carbonate bound Cu.There was no good correlation between the accumulation of Zn in rice seeds and any labile fractions of Zn in soils.The contents and bioavailability of different labile heavy metals fractions had various dependencies on the soil physical-chemical properties.The contents of labile Cd were mainly correlated to soil organic matters,pH and bulk density significantly(P<0.01) while the contents of labile Cr were also related to CEC besides these factors.The contents of labile Pb were related to soil organic matter content,bulk density,medium fine silt and sand content.The contents of labile Cu were affected by clay and organic matter contents significantly while the contents of labile Zn were affected by the pH,organic matter,sand and bulk density.In summary,the major common factors that had apparent effects on the labile contents of Cd,Cr,Pb,Cu and Zn in soils were organic matter,pH and bulk density while the properties related to soil adsorption such as particle size distribution and CEC have little effects on the contents of labile heavy metal fractions in these paddy soils.
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