不同固定剂对铬污染土壤的原位修复

Different Fixatives on the in-situ Remediation of Chromium-contaminated Soil

以某中度铬污染土壤为研究对象,通过室内模拟固定原位修复实验,探究石灰、天然沸石、钙镁磷肥、硫酸亚铁、氧化镁5种固定剂对铬各形态的影响并对生物可利用性进行评价。结果表明:固定剂的添加使Cr残渣态比例增加,易于被植物利用的弱酸提取态减少,从而使铬的生物利用性降低。5种固定剂中氧化镁固定化后的土样中铬的残渣态转化率为19.72%,生物可利用系数为0.048,极大地降低了土壤重金属进入生物链的几率。

Moderate chromium pollution soil was taken as the in-situ remediation research object. Five kinds of fixatives such as the lime, the natural zeolite, the calcium magnesium phosphate, ferrisulfas and magnesium oxide were used to explore their effect on the various forms of chromium. In addition, bioavailability was evaluated. The results showed that： The adding of a fixative increased the proportion of residual chromium, and decreased the portion of weak acid state that easy to be extracted by plants, and the chromium bioavailability was reduced. When magnesium oxide was used, the residual chromium conversion rate reached 19.72 % and the bioavailability factor was 0.048, which greatly reduced the chance of heavy metals into the food chain.