栾树对湘潭锰尾矿土不同处理方式下植被修复盆栽实验

锰矿废弃地植被修复可促进矿区生态环境的改善和经济的可持续发展,植被修复方法和技术措施对锰矿废弃地的修复至关重要,混合基质中尾泥和尾渣的配置比例与配置方式也是提高植物存活率的关键技术措施.本研究采用栾树进行锰矿废弃物(尾泥和尾渣)盆栽试验,探讨不同混合比例处理方式下锰尾矿废弃物的特性以及栾树对重金属锰的植物修复效果.结果表明:(1)锰矿尾泥呈酸性,尾渣呈碱性,尾渣中全Mn和有效Mn含量高于尾泥,二者混合基质的p H值和全Mn含量则随着尾渣含量所占比例的增加而升高,但有效Mn含量则逐渐降低.(2)不同比例的尾泥和尾渣混合基质可以有效改善土壤的物理性质,提高栾树的存活率和改善植物的生长状况;随尾泥含量的增加,栾树总生物量增多,生产力提高,当V(尾渣)∶V(尾泥)=3∶1时的栾树生产力与对照土壤中的栾树生产力相当.(3)从栾树各器官的Mn富集量、生物富集系数和转移系数来看,栾树不属于Mn超富集植物,但作为Mn的低积累植物,属于Mn的耐性树种,具有较强的适应性,可用于锰矿废弃地的植物稳定修复.

Potted experiments with Koelreuteria paniculata on phytoremediation of Mn-contaminated soils from Xiangtan Manganese wastelands

Phytoremediation, using plants to remove pollutants from environment, is a friendly and cost-effective technology for the improvement of ecological environment and economic sustainable development in mining regions. The selection of suitable plant species and corresponding management practice for phytoremediation play important roles in successful restoration in manganese (Mn) mine wastelands. Another equally important technical measure in improving plant survival rate is to explore the appropriate cultivated substrate of the mixture of mining sludge and mining tailing in phytoremediation. In this study, potted experiments with Koelreuteria paniculata were conducted under mixed substrates with different ratios of mining sludges and tailings taken from Xiangtan Mn wastelands, and the effects of phytoremediation potential of K. paniculata for Mn-contaminated mixed substrates were investigated. The results showed that the manganese mining sludges were acidic, but the mining tailings were alkaline. The contents of total Mn and effective Mn were higher in mining tailings than in mining sludges. The pH and total Mn content in the mixed substrates increased with increasing tailings proportion, but the content of effective Mn showed an opposite tendency. The soil physical properties, K. paniculata survival rates and tree growing conditions were closely related with the proportion of mining sludges and mining tailings in the mixed substrates. The biomass and productivity of K. paniculata increased with increasing mining sludge contents in the mixed substrates. When the ratio of mining tailings to mining sludges was 3:1 in the mixed cultivated substrates, the biomass and productivity of K. paniculata in these substrates were most similar to those in the control. Based on total accumulations, biological concentration factor (BCF) and translocation factor (TF), it was found that the K. paniculata was not a suitable hyer-accumulator but a patience tree species with strong adaptability in Mn-contaminated environments. Our study suggests that K. paniculata species is suitable to be cultivated in Mn mining wastelands to restore the contaminated mine soils.