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

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.