title: Combined remediation of DDT congeners and cadmium in soil by Sphingobacterium sp. D-6 and Sedum alfredii Hance.
abstract: Combined pollution of 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) and cadmium (Cd) in agricultural soils is of great concern because they present serious risk to food security and human health. In order to develop a cost-effective and safe method for the removal of DDTs and Cd in soil, combined remediation of DDTs and Cd in soil by Sphingobacterium sp. D-6 and the hyperaccumulator, Sedum alfredii Hance was investigated. After treatment for 210 days, the degradation half-lives of DDTs in soils treated by strain D-6 decreased by 8.1% to 68.0% compared with those in the controls. The inoculation of strain D-6 into soil decreased the uptake of DDTs by pak choi and S. alfredii. The shoots/roots ratios of S. alfredii for the Cd accumulation ranged from 12.32 to 21.75. The Cd concentration in soil decreased to 65.8%-71.8% for S. alfredii treatment and 14.1%-58.2% for S. alfredii and strain D-6 combined treatment, respectively, compared with that in the control. The population size of the DDTs-degrading strain, Simpson index (1/D) and soil respiratory rate decreased in the early stage of treatment and then gradually increased, ultimately recovering to or exceeding the initial level. The results indicated that synchronous incorporation of strain D-6 and S. alfredii into soil was found to significantly (p < or = 0.05) enhance the degradation of DDTs in soil and the hyperaccumulation of Cd in S. alfredii. It was concluded that strain D-6 and S. alfredii could be used successfully to control DDTs and Cd in contaminated soil.
authors.affiliation: Department of Plant Protection, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou 310058, China. agri@zju.edu.cn
authors.forename: Hua
authors.initials: H
authors.lastname: Fang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.forename: Zhengya
authors.initials: Z
authors.lastname: Cao
authors.forename: Feifan
authors.initials: F
authors.lastname: Tang
authors.forename: Dandan
authors.initials: D
authors.lastname: Wang
authors.forename: Kailin
authors.initials: K
authors.lastname: Liu
authors.forename: Xiangwei
authors.initials: X
authors.lastname: Wu
authors.forename: Xiao'e
authors.initials: X
authors.lastname: Yang
authors.forename: Yongge
authors.initials: Y
authors.lastname: Sun
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Yu
mesh_terms: D001673:Biodegradation, Environmental; D002104:Cadmium / Q000378:metabolism*; D003634:DDT / Q000378:metabolism*; D031963:Sedum / Q000378:metabolism*; D012989:Soil Pollutants / Q000378:metabolism*; D045249:Sphingobacterium / Q000378:metabolism*
chemical_list: D012989:Soil Pollutants; D002104:Cadmium; D003634:DDT