利用DGT高分辨率研究沉积物孔隙水中重金属的浓度和释放通量  

High Resolution Measurement of Concentrations and Fluxes of Heavy Metals in Pore Waters by DGT

作　　者：范英宏[1] 林春野[1] 何孟常[1] 周豫湘[1] 杨志峰[1] 

机构地区：[1]北京师范大学环境学院水环境模拟国家重点实验室,北京100875

出　　处：《环境科学》2007年第12期2750-2757,共8页Environmental Science

基　　金：国家重点基础研究发展规划(973)项目(2004CB418502);国家自然科学基金项目(40671002)

摘　　要：2006年5月采集了大辽河河段3个忙状沉积物，测定了沉积物的理化性质和重金属元素的含量，并利用常规离心方法和DGT方法测定了柱状沉积物孔隙水中重金属元素的含量．研究发现沉积物中cd、co、cr和cu元素含量高低的顺序依次是Cr〉Cu〉Co〉Cd．用DGT方法测定的孔隙水中cd、co、cr和cu的浓度比用离心方法测定的浓度要低．DGT测定的孔隙水中cd、co、cr和cu的浓度Cdgt与离心方法测定的孔隙水浓度c的平均比值JR分别为0．389、0．328、0．863和0．403，这说明沉积物中这几种金属从固相到液相的再补给速率大小遵循如下规律：Cr〉Cu〉Cd〉Co．沉积物中cd、co、cr和cu元素的释放通量分别为1．12×10^-7～3．28×10^-7mmol／（cm^2·s）、2．48×10^-7～10．40×10^-7mmol／（cm^2·s）、8．80×10^-6～12．65×10^-6mmol／（cm^2·s）和6．14×10^～6-13．93×10^-6mmol／（cm^2·s）．相关分析结果表明，cd和cu元素的迁移转化主要受有机质影响；而cr元素的迁移转化除了受有机质影响外，还受铁锰氧化物影响比较显著；而co元素可能受氧化还原电位影响较大．Three sediment cores were collected from the Daliao River system in May 2006. The physico-chemical characteristics and heavy metal contents of sediment cores were analyzed. The vertical profiles of metals in pore water were measured by diffusive gradient in thin films （DGT） and centrifugal methods separately. The sequence of the concentrations of Cd, Co, Cr and Cu in sediment is Cr 〉 Cu 〉 Co 〉 Cd. The concentrations measared by DGT were lower than that measured by centrifugal method. The average ratios of DGT measured concentrations （ CDgT ） to the concentrations measured by centrifugal method of Cd, Co, Cr and Cu were 0. 389, 0. 328, 0. 863 and 0.403, respectively. This suggested that the release rates of these metals from solid phase to solution followed the sequence of Cr〉 Cu 〉 Cd 〉 Co. The fluxes of Cd, Co Cr and Cu were 1.12 × 10^-7 - 3.2g ×10^-7 nmol/（cm^2·s）, 2.48 × 10^-7 -- 10.40 × 10 ^-7 nmol/（cm^2·s）, 8.80 × 10^-6 -- 12.65 × 10^-6 nmol/（cm^2·s） and 6.14 × 10^-6 -- 13.93 × 10^-6 nmol/（cm^2·s）, respectively. The result showed that the release of Cd and C u was mainly influenced by organic matter （OM） , while Fe oxides, Mn oxides and OM were major factors controlling the transfer of Cr. The redox potential may be the major factor influencing the release of Co element.

关 键 词：DGT 重金属 孔隙水 沉积物 

分 类 号：X132[环境科学与工程—环境科学]