土壤中重金属化学形态与植物吸收的关系

Study on the correlation between the chemical forms of the heavy metals in soil and the metal uptake by plant

采用TessierA连续提取法,测定了辽宁双台子河口土壤中重金属(Cd、Zn、Pb、Cu)的质量分数和5种形态,研究了在当地pH=5.33土质条件下自然生长的潮滩植物芦苇对重金属可利用性.实验发现,芦苇对重金属的吸收与金属的形态密切相关,芦苇中各部位金属的质量分数WPhyto的变化与土壤中金属的质量分数的可交换态WExch与碳酸盐结合态WCarb之和相一致,而与余下的其他3种形态没有明确关联.对没有新污染源的情况下,植物能在多少年内清除掉土壤中污染重金属,使土壤达到安全值以下进行了预测,得到Cd需要12.8年,Zn需要1.1年,Pb需要74.8年,Cu需要9.4年,这说明芦苇对该地区土壤中的Pb吸收作用非常小.

Tessier A sequential analysis to measure the aggregate concentration or 5 individual chemical forms (the exchangeable, carbonates, Fe-Mn oxides, organic bounds and residuals) of heavy metal element in soil at Shuangtaizi bayou, Liaoning, was used as the research tools to investigate the metal uptake effect of the tideland plant. Phragmites communis Experimental analyses reveal that the metal uptake of plant depends on the existing chemical states of metals. The first two forms (the exchangeable and the carbonates ) are extractable by plant in soil at pH 5.33, but the others are obviously not.