污染土壤中重金属的可萃取性与生物可利用性

Extractability and Bioavailability of Heavy Metals in Surface Soil Derived from Smelting Zinc

采用 5种常用的单一萃取剂进行污染土壤中重金属元素Cu、Pb、Zn和Cd可萃取性研究 .结果发现 :中性盐CaCl2 和NaNO3的萃取效率远低于其它三种具有络合(HOAc、NH4 OAc)或螯合 (EDTA )性质的单一萃取剂 ;污染土壤中生长的农作物 (玉米和土豆 )体内重金属含量也高于中性盐CaCl2 和NaNO3从土壤中萃取出来的量 .这说明植物不仅可以吸收和利用土壤中以可交换态形式存在的这一部分重金属 。

Five different single extractants were used to evaluate the chemical mobility of heavy metals in polluted soil. Results indicate that the extraction efficiency of neutral salts, such as CaCl 2 and NaNO 3, is much less than those compounds, which have coordinating groups, for example, HOAc, NH 4OAc and EDTA. Meanwhile, the content of heavy metals in crops growing in the polluted soil is higher than the concentration extracted with neutral salts. This imply crops can absorb not only those metals existing as exchangeable bound, but also existing as other chemical forms.