改良剂对尾砂盆栽蔬菜重金属吸收及基质理化性质的影响——以铜陵金属矿区为例

Influences of Different Modifiers on Heavy Metal Absorption by Tailings Potted Vegetable and Physicochemical Properties of Matrix -A Case Study in Tongling Metal Mining Area

研究了加入不同改良剂改良的尾砂种植蔬菜后,重金属在尾砂-植物界面的迁移规律及尾砂基质pH值和物理结构的变化。基质以安徽铜陵矿尾砂为主,加入20%有机质,进行了配土(红壤20%)和不配土对比,改良剂选择聚丙烯酰胺(PAM)和乙二胺四乙酸(EDTA)2种。结果表明:添加土壤改良尾砂后对植物吸收重金属尤其是Cu有明显的抑制作用;加入EDTA和PAM后可以进一步抑制叶类植物对重金属的吸收;PAM对土壤颗粒的粘结作用较EDTA明显,对土壤结构变化有一定的促进作用;不同处理的基质pH值均介于7～8之间,可见配土和添加改良剂不会造成基质之间pH值的根本性变化。

Planting vegetables in the tailings added with different modifiers, the migration law of heavy metals on the railings-plants interface and changes of the pH values and the physical structure of tailing matrix were studied. The matrix is combined by Anhui Tongling ore tailings with 20% organic matter, and blending with soil （20% red soil） or without, and two modifiers （PAM and EDTA） were chosen. The results showed that modifying tailings by adding soil will inhibit heavy metal absorption by plants, especially for Cu, moreover, adding EDTA and PAM can further restrain the heavy metal absorption by leafy plants; PAM have more obvious adhesive effect on soil particles in comparison with EDTA, which can improve soil structure to a certain degree; the pH value of matrix in each treatment all varied during 7-8, which means blending with soil and adding modifier would not cause thorough change in pH value of matrix.