Changes in Metal Availability and Improvements in Microbial Properties After Phytoextraction of a Cd, Zn and Pb Contaminated Soil

Assessing the effects of phytoextraction on soil properties is important for successful implementation of this method. This study was conducted to evaluate the effects of phytoextraction by Sedum alfredii Hance on the availability of metals and improvement of the microbial community (biomass and structure) of a Cd, Zn and Pb contaminated soil. Phytoextraction significantly decreased the acid extractable, Mn/Fe oxide and organic matter bound fractions of Cd and Zn as well as the acid extractable Pb in the rhizosphere soil. Soil microbial biomass, total, bacterial, actinomycete, fungal, AM fungal, and protozoa phospholipid fatty acids (PLFAs) were significantly enhanced. The ratio of fungal to bacterial and gram-positive to gram-negative bacterial PLFAs were significantly changed. Redundancy analysis showed that microbial biomass and specific groups of PLFAs were negatively correlated with available metals while positively correlated with dissolved organic carbon/organic acids. In conclusion, phytoextraction by S. alfredii reduced available metal concentrations and improved soil microbial properties.