超积累植物和化学改良剂联合修复锌镉污染土壤后的微生物特征

Microbial characteristics of a Zn and Cd contaminated soil chemically amended for growth of a heavy metal-hyperaccumulating plant

通过盆栽试验,观察分析不同的土壤改良配方对重金属超积累植物东南景天盆栽土壤中细菌、真菌和放线菌数量、Cmic及Nmic的影响,以此来筛选出最优的促进东南景天修复锌镉污染土壤的改良剂配方。结果显示:细菌、真菌和放线菌数量,与土壤Zn、Cd的去除率、东南景天植株干质量、Cmic及Cmic/Nmic两两之间都呈现极显著正相关关系(但Cmic/Nmic与真菌数量仅呈显著相关)。添加了土壤改良剂后,细菌、放线菌、真菌的数量都有不同程度的增加,其中以细菌数量的增加最为显著,放线菌次之,真菌则对各种土壤处理相对较不敏感;在各种土壤配方中,添加了6 g赤泥、15 g污泥和15 g沸石的T7处理最有利于各类土壤微生物的生长,微生物量碳达到345.64 mg.kg-1,与其它处理之间都达到显著差异。因此,可以利用土壤微生物作为污染土壤改良情况的生物指标。该研究为下阶段研究化学改良剂-植物-微生物修复技术奠定了基础。

A pot experiment was conducted to examine the effects of chemical amendment on the microbial characteristics of a heavy metal-contaminated soil used for the growth of a hyperaccumulating plant, Sedum alfredii Hance. The results show that the abundance of the soil microbes （ bacteria, actinomycetes and fungi ） is significantly （at p=0.01） related to the removal rate of Zn and Cd from the soil, the dry biomass of Sedum alfredii Hance, Cmic, and Cmic/Nmic except that the number of fungi is only significantly （at p=0.05） related to Cmic/Nmic. All the soil treatments enhanced the activities of soil microbes. In general, the increase in activity of different types of microbes was in the following decreasing order： bacteria〉actinomycetes〉fungi. Of all the treatments, Treatment 7 （mixing 1 000 g of the contaminated soil with 6 g of red mud, 15 g of zeolitic rock powder and 15 g of biosolids） formed a best soil medium for the growth of the soil microbes. The microbial biomass C concentration in Treatment 7 was as high as 345.64 mg·kg^-1, which was statistically different from other treatments and represented the highest value among all the treatments in this experiment. This work has implications for the future development of a combined chemical and biological remediation technique for the cleanup of Zn and Cd contaminated soils.