Phytoextraction of Pb and Cu Contaminated Soil With Maize and Microencapsulated EDTA

Abstract

Chelate-assisted phytoextraction using agricultural crops has been widely investigated as a remediation technique for soils contaminated with low mobility potentially toxic elements. Here, we report the use of a controlled-release microencapsulated EDTA (Cap-EDTA) by emulsion solvent evaporation to phytoremediate soil contaminated with Pb and Cu. Incubation experiments were carried out to assess the effect of Cap- and non-microencapsulated EDTA (Ncap-EDTA) on the mobility of soil metals. Results showed EDTA effectively increased the mobility of Pb and Cu in the soil solution and Cap-EDTA application provided lower and more constant water-soluble concentrations of Pb and Cu in comparison with. Phytotoxicity may be alleviated and plant uptake of Pb and Cu may be increased after the incorporation of Cap-EDTA. In addition phytoextraction efficiencies of maize after Cap- and Ncap-EDTA application were tested in a pot experiment. Maize shoot concentrations of Pb and Cu were lower with Cap-EDTA application than with Ncap-EDTA. However, shoot dry weight was significantly higher with Cap-EDTA application. Consequently, the Pb and Cu phytoextraction potential of maize significantly increased with Cap-EDTA application compared with the control and Ncap-EDTA application.

KEY WORDS::

• soil
• Pb
• Cu
• phytoremediation
• maize
• microencapsulated EDTA

ACKNOWLEDGMENTS

We thank the National Natural Science Foundation of China (Project 30571117), the Important Sci-Tech Special Project of Guangdong Province, China (Project 2008A03020 2004) and the Key Sci-Tech project of Guangdong Province, China (Project 2006A3670 3004) for financial support. We thank Prof. Peter Christie, Agri-Food and Biosciences Institute, Belfast, United Kingdom, for revising the manuscript.