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United States Department of Agriculture

Agricultural Research Service

Research Project: SUSTAINABLE CROPPING SYSTEMS FOR IRRIGATED SPECIALTY CROPS AND BIOFUELS

Location: Vegetable and Forage Crops Production Research

Title: Pig manure vermicompost (PMVC) can improve phytoremediation of Cd and PAHs co-contaminated soil by Sedum alfredii

Authors
item Wang, Kai -
item Zhang, Jie -
item Zhu, Zhiqiang -
item Huang, Huagang -
item Li, Tingqiang -
item He, Zhenli -
item Yang, Xiaoe -
item Alva, Ashok

Submitted to: Journal of Soils and Sediments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 15, 2013
Publication Date: June 20, 2013
Citation: Wang, K., Zhang, J., Zhu, Z., Huang, H., Li, T., He, Z., Yang, X., Alva, A.K. 2013. Pig manure vermicompost (PMVC) can improve phytoremediation of Cd and PAHs co-contaminated soil by Sedum alfredii. Journal of Soils and Sediments. 12:1089-1099.

Interpretive Summary: Widespread acceptance of phytoremediation technologies is dependent on effectiveness of a technology for simultaneous removal of multiple pollutants. In this study, planting of Sedum alfredii (a hyperaccumulator of various metals including cadmium (Cd)) and application of pig manure vermicompost (PMVC) were evaluated for removal of Cd and polycyclic aromatic hydrocarbons (PAHs) in a co-contaminated soil. Application of PMVC increased the top and root biomass of Sedum plants, therefore increased the removal of Cd as well as dissipation of PAHs. Therefore, this strategy has the merit of remediation of multiple pollutants from contaminated soils.

Technical Abstract: Purpose Main challenge of phytoremediation of co-contaminated soils is developing strategies for efficient and simultaneous removal of multiple pollutants. A pot experiment was conducted to investigate the potential for enhanced phytoextraction of cadmium (Cd) by Sedum alfredii and dissipation of polycyclic aromatic hydrocarbons (PAHs) in co-contaminated soil by application of pig manure vermicompost (PMVC). Soil contaminated by Cd (5.53 mg kg-1 DW) was collected from a trial field in Zhejiang University, China, and was spiked with phenanthrene, anthracene and pyrene (250 mg kg–1 DW for each PAH). A pot experiment was conducted in a greenhouse with four treatments: (1) soil without plants (Control), (2) soil planted with S. alfredii (Plant), (3) soil amended with 5% PMVC (PMVC), and (4) soil planted with S. alfredii and amended with 5% PMVC (Plant + PMVC). After 90 days, shoot and root biomass of plants, Cd concentrations in plant and soil and PAHs concentrations in soil were determined. Abundance of PAH degraders and soil bacterial community structure were investigated. Soil enzyme activity and microbial biomass carbon were measured. Application of 5% PMVC increased the shoot and root dry biomass of S.alfredii by 2.27-fold and 3.93-fold, respectively, thus increased Cd phytoextraction without inhibition of soil microbial population and enzyme activities. The dissipation rate of PAHs in Plant + PMVC treatment was the highest across all the treatments. However, S. alfredii and PMVC did not enhance PAHs dissipation when applied separately. The dissipation rate of PAHs was not related to abundance of PAH degraders in soil. Plant + PMVC treatment significantly influenced the bacterial community structure. Enhanced dissipation of PAHs in the Plant + PMVC treatment could be due to the improvement of plant root growth, which may result in increased root exudates, and subsequently change bacterial community structure to be favorable for PAHs dissipation. This study demonstrated that remediation of Cd and PAHs co-contaminated soil by S. alfredii can be enhanced by simultaneous application of PMVC. Long term evaluation of this strategy in co-contaminated field sites is pending.

Last Modified: 4/19/2014