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Title: Bioremediation of Cd-DDT co-contaminated soil using the Cd-hyperaccumulator Sedum alfredii and DDT-degrading microbes

item ZHU, ZHI-QIANG - Zhejiang University
item YANG, XIAO-E - Zhejiang University
item WANG, KAI - Zhejiang University
item HUANG, HUA-GANG - Zhejiang University
item ZHANG, XIN-CHENG - Zhejiang University
item FANG, HUA - Zhejiang University
item LI, TING-QIANG - Zhejiang University
item Alva, Ashok
item HE, ZHEN-LI - University Of Florida

Submitted to: Journal of Hazardous Materials
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2012
Publication Date: 12/20/2012
Citation: Zhu, Z., Yang, X., Wang, K., Huang, H., Zhang, X., Fang, H., Li, T., Alva, A.K., He, Z. 2012. Bioremediation of Cd-DDT co-contaminated soil using the Cd-hyperaccumulator Sedum alfredii and DDT-degrading microbes. Journal of Hazardous Materials. 235:144-151.

Interpretive Summary: Soils contaminated with pollutants often contain multiple pollutants, i.e. heavy metals and organic pollutants. Therefore, technologies must be developed for remediation of multiple pollutants. In this study an integrated strategy was developed for bioremediation of cadmium (Cd) and DDT co-contaminated soils. A Cd hyperaccumulator plant (Sedum alfredii) and DDT degrading microbes were simultaneously used. The above strategy decreased Cd by 32-40% and DDT by 34-38%. Efficacy of this integrated strategy was also demonstrated in a field experiment as evident from removal of 31% of Cd and 54% DDT over 18 months period.

Technical Abstract: The development of an integrated strategy for the remediation of soil co-contaminated by heavy metals and persistent organic pollutants is a major research priority for the decontamination of soil slated for use in agricultural production. The objective of this study was to develop a bioremediation strategy for fields co-contaminated with cadmium (Cd), dichlorodiphenyltrichloroethane (DDT), and its metabolites DDE and DDD (DDT, DDE, and DDD expressed in this paper as DDs) using the Cd hyperaccumulator plant Sedum alfredii (SA) and DDT-degrading microbes (DDT-1). Initially, inoculation with DDT-1 was shown to increase SA root biomass in a pot experiment. When SA was applied together with DDT-1, the levels of Cd and DDs in the co-contaminated soil decreased by 32.1–40.3% and 33.9–37.6%, respectively, in a pot experiment over 18 months compared to 3.25% and 3.76% decreases in soil Cd and DDs, respectively, in unplanted, untreated controls. A subsequent field study (18-month duration) in which the levels of Cd and DDs decreased by 31.1% and 53.6%, respectively, confirmed the beneficial results of this approach. This study demonstrates that this integrated bioremediation strategy is effective in the remediation of Cd-DDs co-contaminated soils.