Tu Chen, Wei Jing, Guan Feng, Liu Ying, Sun Yuhuan, Luo Yongming
CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
Environ Int. 2020 Apr;137:105576. doi: 10.1016/j.envint.2020.105576. Epub 2020 Feb 18.
The application of biochar in the remediation of heavy metal contaminated soil has received increasing global attention during the past decade. Although there has been some review work on the mechanism of heavy metals stabilization by biochar, the effects and mechanisms of interaction between biochar and functional microbes such as heavy metal tolerant, adsorption and transformation microbial strains remains unclear. In this paper, maize biochar and a heavy metal-tolerant strain Pseudomonas sp. NT-2 were selected to investigate the dynamic effects and potential mechanisms of biochar and bacteria loaded biochar on the stabilization of Cd and Cu mixed contaminated soil by a 75-day pot experiment. The results showed that, compared to the single biochar amendment, the application of biochar inoculated with NT-2 strain at the rate of 5% significantly increased the soil pH at the initial stage of incubation, and followed by a slight decline to a neutral-alkaline range during the reaction. The addition of NT-2 loaded biochar could also significantly increase the proportion of residual fraction of Cd and Cu, thus reduce the proportion of exchangeable and carbonate bound species in the soil, which lead to the decreasing of plant and human bioavailability of the metal in the soil indicated by DTPA and simulated human gastric solution extraction (UBM), respectively. Finally, the application of bacterial loaded biochar also markedly enhanced soil urease and catalase activities during the later stage of the incubation, and improved soil microbial community at the end of incubation, which indicates a recovery of soil function after the metal stabilization. The research results may provide some new insights into the development of functional materials and technologies for the green and sustainable remediation of heavy metal contaminated soil by the combination of biochar and functional microorganisms.
在过去十年中，生物炭在重金属污染土壤修复中的应用受到了全球越来越多的关注。尽管已经有一些关于生物炭稳定重金属机制的综述工作，但生物炭与重金属耐受、吸附和转化微生物菌株等功能微生物之间相互作用的影响和机制仍不清楚。本文通过75天的盆栽试验，选用玉米生物炭和一株重金属耐受菌株假单胞菌NT-2，研究了生物炭和载菌生物炭对镉和铜混合污染土壤稳定化的动态影响及潜在机制。结果表明，与单一生物炭改良相比，接种NT-2菌株的生物炭以5%的比例施用在培养初期显著提高了土壤pH值，随后在反应过程中略有下降至中性-碱性范围。添加载有NT-2的生物炭还可显著提高镉和铜残留态的比例，从而降低土壤中可交换态和碳酸盐结合态的比例，分别导致土壤中金属的植物和人体生物有效性降低，这通过DTPA和模拟人体胃液提取（UBM）来表示。最后，施用载菌生物炭在培养后期也显著提高了土壤脲酶和过氧化氢酶活性，并在培养结束时改善了土壤微生物群落，这表明金属稳定化后土壤功能得到恢复。研究结果可能为通过生物炭和功能微生物结合开发绿色可持续修复重金属污染土壤的功能材料和技术提供一些新的见解。
