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| Effects of passivating agents on the availability of Cd and Pb and functional diversity of the microbial community in contaminated soils |
| Received:July 31, 2019 |
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| KeyWord:sepiolite;biochar;Cd-Pb pollution;bioavailability;microbial community diversity |
| Author Name | Affiliation | | ZHANG Di | School of Environmental Science, Nanjing Xiaozhuang University, Nanjing 211171, China | | LI Ting | School of Environmental Science, Nanjing Xiaozhuang University, Nanjing 211171, China | | FANG Xuan | School of Environmental Science, Nanjing Xiaozhuang University, Nanjing 211171, China | | WU Xiao-xia | School of Environmental Science, Nanjing Xiaozhuang University, Nanjing 211171, China | | DING Ai-fang | School of Environmental Science, Nanjing Xiaozhuang University, Nanjing 211171, China |
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| Abstract: |
| The effects of sepiolite and biochar on the remediation of soil contaminated with cadmium and lead and the functional diversity of soil microbial community were studied. A pot experiment was conducted to investigate the effect of single and combined application of sepiolite and biochar on Cd-Pb contaminated soil samples collected from vegetable bases in Nanjing. Changes in soil physiochemical properties, functional diversity of soil microbial community, availability of soil Cd and Pb, and accumulation of Cd and Pb in radish(Raphanus sativus L.)and pakchoi(Brassica chinensis L.)were estimated. The results indicated that application of passivating agents could effectively promote the transformation of Cd and Pb from acid soluble to residual forms, and decrease the contents of available Cd and Pb in the tested soil. The largest degree of reduction for Cd and Pb contents was observed in the treatment with 2.5% sepiolite. Compared with the control treatment, the contents of soil available Cd and Pb decreased by 71.88%~75.44% and 81.21%~84.52% with radish and pakchoi, respectively. Biochar had a significant effect on soil microbial activity, and microorganisms exhibited the strongest ability of carbon source utilization upon treatment with 2.5% biochar. However, there was no significant increase in the functional diversity of soil microbial community. Application of sepiolite and biochar reduced the enrichment of Cd and Pb in edible parts of radish and pakchoi. The contents of Cd and Pb in edible parts of radish met the limit set by the National Food Safety Standard of the People's Republic of China(GB 2762-2017)upon treatment with 2.5% sepiolite and 1.25% sepiolite combined with 1.25% biochar. However, the content of Pb in the edible part of pakchoi exceeded the food safety standards. From the perspective of soil quality and crop safety, our results suggest that the combination of sepiolite and biochar is effective for the remediation of Cd-Pb contaminated soil, and root vegetables such as radish could be grown in soil contaminated with moderate amounts of Cd-Pb. |
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