两种污染土壤中重金属Pb Cd Zn的EDTA萃取及形态变化  

EDTA Extraction and Changes of Pb,Cd,and Zn Fractions in Two Contaminated Soils

作　　者：雷鸣[1] 廖柏寒[2] 曾清如[1] 周细红[1] 刘丽[1] 

机构地区：[1]湖南农业大学资源环境学院,湖南长沙410128 [2]中南林学院资源与环境学院,湖南长沙410004

出　　处：《农业环境科学学报》2005年第6期1233-1237,共5页Journal of Agro-Environment Science

基　　金：科技部中法先进研究计划(PRAE00-04);教育部科学技术研究重点项目(教技司[2000]156-00209);湖南省教育厅重点科研项目(00A003)

摘　　要：用Tessier连续提取法研究了EDTA萃取前后受污染覆盖土和灌溉土土壤中重金属Pb、Cd、Zn的形态变化。结果表明,2种污染土壤中的重金属Pb、Cd、Zn的形态分布各有差异,均以残渣态为主。在5.0mmol·L-1浓度条件下,EDTA对Pb和Cd的萃取能力较其对Zn的萃取能力强;经EDTA萃取后的土壤中Pb、Cd、Zn残渣态、碳酸盐结合态、铁锰氧化物结合态、交换态含量分别有所下降,Pb和Cd减少顺序为残渣态>碳酸盐结合态>铁锰氧化物结合态>交换态,Zn减少顺序为残渣态>交换态>铁锰氧化物结合态>碳酸盐结合态;而有机物结合态Pb、Cd、Zn的含量却有所增加,其增加幅度为Zn>Pb>Cd。In order to evaluate chemical behaviors and bioavailability of heavy metals in contaminated soils, two types of topsoil samples were collected at a Pb-Zn mining area located in Chenzhou city, southern Hunan Province （southern China）, where mining activities of heavy metals have been conducted for about 500 years and ore waste tailings have been piled up around. In recent decades, high contents of heavy metals such as Pb, Cd, Zn, Cu, Cr, and As have been found in environment nearby due to the collapse of a tailing dam in 1985, especially in the soils and stream water, The batch experiment of effect on fractions distribution of Pb, Cd, and Zn the two contaminated soils before and after extracted by an EDTA solution was carried. And Tessier＇s sequential extraction technique was conducted for in two contaminated soils. The results showed that before EDTA extraction, the two tested soils had different fractions distribution of Pb, Cd, and Zn, and the most important fractions were all residual forms. An EDTA solution of 5.0 mmol·L^-1 had a stronger ability to extract soil Pb and Cd than soil Zn. After EDTA extraction, fractions of Pb, Cd, and Zn bound to residual, carbonate, Fe/Mn oxides, and exchangeable forms decreased to some extent. For Pb and Cd, decreased amounts of the fractions were in a sequence of residual, carbonate, Fe/Mn oxides, and exchangeable forms; for Zn, however, this sequence was residual 〉 exchangeable 〉 Fe/Mn oxides 〉 carbonate forms. EDTA extraction led to increases of Pb, Cd, and Zn bound to organic matter, and the increased amounts were Zn 〉 Pb 〉 Cd.

关 键 词：污染土壤 重金属 乙二胺四乙酸二钠盐 形态分布 

分 类 号：X53[环境科学与工程—环境工程]