重金属在土壤中的形态分布及其在空心菜中的富集研究

通过盆栽实验,研究了Cu、Zn、Pb、Cd在空心菜中的富集作用,并采用BCR提取方法,对盆栽土壤中4种重金属的化学形态进行了分析.研究结果表明,Cd主要以水溶态、可交换态、碳酸盐结合态和Fe-Mn氧化物结合态为主;Pb主要以残渣态为主;Zn主要以残渣态和水溶态、可交换态、碳酸盐结合态为主;Cu在土壤中的形态分布与土壤中Cu的含量有关.4种重金属的生物有效性表现为Cd>Zn>Cu>Pb.重金属在空心菜中的吸收富集能力与土壤中重金属的形态,尤其是水溶态、可交换态、碳酸盐结合态关系密切.空心菜中重金属富集系数大小表现为Cd>Zn>Cu>Pb.空心菜地下部4种重金属富集系数远远高于地上部.

Forms of Heavy Metals in Soil and Their Bioconcentration in Swamp Cabbage

Pot experiments were conducted to study the bioconcentration of Cu, Zn, Pb and Cd in swamp cabbage , and chemical forms of heavy metals in soil were analysised using BCR sequential extraction procedure. The results showed that Cd was mainly associated with water soluble, exchangeable, carbonate fractions and Fe-Mn oxide fractions; Pb was mainly associated with residual fraction; Zn was mainly associated with residual fraction and water soluble, exchangeable, carbonate fractions; the forms of Cu in soil were related with its content of the soil. Bioavailability of the four heavy metals is Cd>Zn>Cu>Pb. Bioconcentration ability of heavy metals in swamp cabbage is closely related with their forms, especially water soluble, exchangeable and carbonate fractions in soil. Bioconcentration factors of the four metals in swamp cabbage is Cd>Zn>Cu>Pb. Bioconcentration factors of the four metals in the root are bigger than that in the stem and leaf.