防止土法炼锌废渣充填场地重金属污染复垦技术

    Reclamation technology on preventing heavy metal pollution from landfill of indigenous zinc smelting areas

    • 摘要: 黔西北赫章县炼锌造成大量的废弃地,土地复垦成为当地面临的主要问题。为大面积的土地复垦提供基础数据,在平整的废渣堆上用0、25和50 kg/m2的碱石灰做隔离层,然后在隔离层上覆以30、45和60 cm的非污染区土壤,共9个处理;选用当地的主要农作物红豆、白菜、玉米和马铃薯进行试验。通过近2 a对红豆、白菜、玉米和马铃薯可食部分和复垦土壤的重金属进行One-Way ANOVA (LSD)分析和富集系数比较得出碱石灰隔离层降低了农作物可食部分的重金属含量;玉米是对重金属富集系数最小的农作物,适合作为土地复垦的首选农作物,而白菜对重金属的富集系数最大,不适合在炼锌区复垦土壤种植;经济有效的碱石灰隔离层厚度为25 kg/m,复垦土壤的厚度为30 cm。

       

      Abstract: Due to indigenous zinc smelting, lots of lands were polluted and abandoned in Hezhang County, Guizhou Province. The reclamation of polluted soils is becoming more important to improve environmental protection and to prompt agricultural production in these areas. In the present study, total of nine treatments of different amount of lime (0, 25 and 50 kg/m2) was used as isolation layer in the flat slag heap, and then the isolation layer was covered with different amount of non-contamination soil (30, 45 and 60 cm), respectively. During the following two years, bean (Phaseolus angularis), Chinese cabbage (Brassica chinensis), maize (Zea mays) and potato (Solanum tuberosum) were planted, concentrations of some metals (Zn, Pb, Cd) in soils and the edible part of the crops were determined to assess the effects of reclamation by statistical analysis of One-Way ANOVA (LSD). The results indicated that metal concentrations in edible part of the crops were decreased by the treatments of limestone isolation layer; maize had the lowest enrichment factor of heavy metals among the four crops, while Chinese cabbage had the highest content, demonstrating that maize was more suitable to be cultivated compared with the others, lime as isolation layer could significantly reduce the accumulation of heavy metals in the edible part of the crops, and 25 kg/m2 lime isolation layer combined with 30 cm non-contamination soil cover showed the effective reclamation result.

       

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