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Environmental Science Pollution Research International
Vol. xx, No: xx, 2012, Pages: xx-xx

Bioremediation of Cd and carbendazim co-contaminated soil by Cd-hyperaccumulator Sedum alfredii associated with carbendazim-degrading bacterial strains

Xiao W, Wang H, Li T, Zhu Z, Zhang J, He Z, Yang X

Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.

Abstract

The objective of this study was to develop a bioremediation strategy for cadmium (Cd) and carbendazim co-contaminated soil using a hyperaccumulator plant (Sedum alfredii) combined with carbendazim-degrading bacterial strains (Bacillus subtilis, Paracoccus sp., Flavobacterium and Pseudomonas sp.). A pot experiment was conducted under greenhouse conditions for 180 days with S. alfredii and/or carbendazim-degrading strains grown in soil artificially polluted with two levels of contaminants (low level, 1 mg kg(-1) Cd and 21 mg kg(-1) carbendazim; high level, 6 mg kg(-1) Cd and 117 mg kg(-1) carbendazim). Cd removal efficiencies were 32.3-35.1 % and 7.8-8.2 % for the low and high contaminant level, respectively. Inoculation with carbendazim-degrading bacterial strains significantly (P<0.05) increased Cd removal efficiencies at the low level. The carbendazim removal efficiencies increased by 32.1-42.5 % by the association of S. alfredii with carbendazim-degrading bacterial strains, as compared to control, regardless of contaminant level. Cultivation with S. alfredii and inoculation of carbendazim-degrading bacterial strains increased soil microbial biomass, dehydrogenase activities and microbial diversities by 46.2-121.3 %, 64.2-143.4 %, and 2.4-24.7 %, respectively. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis revealed that S. alfredii stimulated the activities of Flavobacteria and Bradyrhizobiaceae. The association of S. alfredii with carbendazim-degrading bacterial strains enhanced the degradation of carbendazim by changing microbial activity and community structure in the soil. The results demonstrated that association of S. alfredii with carbendazim-degrading bacterial strains is promising for remediation of Cd and carbendazim co-contaminated soil.

Keywords:bioremediation strategy for cadmium;Bacillus subtilis, Paracoccus sp., Flavobacterium and Pseudomonas sp;carbendazim co-contaminated soil.


 

 

 
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