植物生长对两种稳定化材料修复后镉污染土壤的影响

The impact of plant growth on cadmium-contaminated soil after remediation by two stabilization materials

  • 摘要: 不同稳定化材料修复后土壤在植物生长条件下Cd再释放风险不同,通过盆栽试验,评估了铝酸盐与硅酸盐材料修复后Cd污染土壤在植物生长条件下的Cd浸出程度及植物Cd含量。结果表明,在试验进行30 d时,硅酸盐和铝酸盐材料修复后土壤中高羊茅出苗率均高于对照,硅酸盐材料处理植株中Cd含量远高于铝酸盐处理。在未种植高羊茅处理中,硅酸盐和铝酸盐材料均使土壤Cd浸出浓度(27.83 μg/L)降低,其中铝酸盐材料处理土壤Cd的浸出浓度(12.97 μg/L)较硅酸盐(22.67 μg/L)低,表明铝酸盐材料对Cd的稳定化效果更好。种植高羊茅情况下,硅酸盐处理Cd浸出浓度略有提升。分析土壤酶活性发现,在种植高羊茅和未种植高羊茅处理中,硅酸盐材料使土壤总体酶活性较对照分别降低35.73%和22.58%,而铝酸盐材料则较对照分别提高19.93%和18.71%,表明铝酸盐材料对土壤生化性状具有正面影响。综上所述,铝酸盐材料修复后的Cd污染土壤再释放风险较小,适用于修复后可能有植被生长的Cd污染场地。

     

    Abstract: The risk of cadmium (Cd) re-release from soil remediated under plant growth conditions varies with different stabilizing materials. Pot experiments were conducted to evaluate the degree of Cd leaching and the plant Cd content in cadmium-contaminated soil remediated with aluminate and silicate materials under plant growth conditions. The result showed that at 30 days of the experiment, the germination rate of tall fescue in the soil repaired by both silicate and aluminate materials was higher than that of the control group, and the Cd content in plants treated by silicate materials was better than that of aluminate. In the treatments without tall fescue, silicate and aluminate materials made the leaching concentration of Cd decrease from 27.83 μg/L to 22.67 μg/L and 12.97 μg/L, respectively, indicating that aluminate had a better stabilization effect on Cd. Under tall fescue cultivation, the Cd leaching concentration exhibited a slight increase. By analyzing soil enzyme activity, it was found that in the treatments with and without tall fescue, silicate materials reduced the total soil enzyme activity by 35.73% and 22.58%, respectively, while aluminate materials increased it by 19.93% and 18.71%, respectively. This indicated that aluminate had a positive impact on soil biochemical properties. In conclusion, Cd-contaminated soil remediated with aluminate materials exhibits a lower risk of re-release, and thus aluminate materials are suitable for Cd-polluted sites where vegetation may grow after remediation.

     

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