黔西北土法炼锌废弃地生态修复研究

Ecological Restoration of Indigenous Zinc Smelting Wasteland in Northwest Guizhou

黔西北土法炼锌形成了大量的废弃地,废弃地植被破坏后造成严重水土流失和重金属迁移扩散,当地人多地少,土地复垦和植被恢复显得尤为必要。土法炼锌的废弃地主要由土法炼锌废渣堆放地和土法炼锌时大气污染导致的污染土壤组成。废渣堆放地土壤的重金属含量高,植被恢复的难度大;周边污染土壤的重金属含量相对较低,但可溶性的重金属含量大,当地进行土地复垦种植农作物存在危害人体健康的潜在风险。根据废渣堆放地和污染土壤的特点,因地制宜地利用重金属的植物稳定技术和植物提取技术,选择巨菌草(Pennisetum sp.)、大叶醉鱼草(Buddleja davidii Franch.)等重金属耐性植物尽快恢复废渣堆放地的植被,减少因为水土流失导致的重金属迁移扩散;选用南黄堇(Corydalis davidii Franch.)对污染土壤重金属进行植物提取,减少污染土壤重金属含量后再进行土地复垦。

A large number of wastelands have been formed in the process of indigenous zinc smelting in Northwest Guizhou.The destruction of vegetation in the wasteland has caused serious soil erosion and heavy metal migration and diffusion.There are more local people and less land,so land reclamation and vegetation restoration are particularly necessary.The waste land of indigenous zinc smelting mainly consists of the waste residue dump and the polluted soil caused by air pollution during indigenous zinc smelting.The content of heavy metals in the soil of waste dump is high,which makes it difficult to restore vegetation。The content of heavy metals in polluted soil is relatively low,but the soluble heavy metals are high.There is a potential risk to human health in local land reclamation and planting crops.According to the characteristics of waste dump and polluted soil,plant stabilization technology and plant extraction technology of heavy metals were used according to local conditions.Pennisetum sp.and Buddleja davidii were selected Heavy metal tolerant plants.They coould recover the vegetation of the waste dump as soon as possible,so as to reduce the migration and diffusion of heavy metals caused by soil erosion.The heavy metals in the polluted soil were extracted by plants with Corydalis davidii Franch.The content of heavy metals in the polluted soil was reduced before land reclamation.