Chelate-assisted phytoextraction is a promising technique to remediate metal-contaminated soil. Batch and greenhouse experiments were conducted to assess the effects of synthetic chelators (ethylenediaminetetraacetic acid [EDTA], ethylenediaminedisuccinic acid [EDDS], and nitrilotriacetic acid) and low-molecular-weight organic acids (oxalic and citric acids) on the solubilization of copper, chromium, and arsenic (Cu, Cr, and As, respectively) in chromated Cu arsenate (CCA)-contaminated soil and on metal uptake and translocation in maize (Zea mays L.). Chelators significantly enhanced the solubilization of Cr, Cu, and As in the soil and markedly increased their accumulation in plant tissues. Applying 5 and 10 mmol kg−1 EDDS increased plant Cu uptake by 2.8- and 3.5-fold greater than that in control soil (without chelate applications), respectively. EDTA and citric acid were more efficient for increasing Cr uptake by plant shoots, resulting in 5.0- and 5.5-fold increases, respectively, compared with that in the control. Maximum As uptake was observed in response to a treatment of 10 mmol kg−1 citric acid, which was 1.9-fold greater than that in control soil. However, translocation factors, phytoextraction efficiencies, and remediation factors indicated that metal uptake was not high enough for successful phytoremediation of CCA–contaminated soil. Our results suggest that EDDS and citric acid as alternatives to EDTA may facilitate phytoextraction of contaminated soil.
1Department of Biological Environment, Kangwon National University, Chuncheon, Korea;
2Department of Biology, College of Science, Umm Al-Qura University, Makkah, Saudi Arabia;
3Department of Agronomy & Medicinal Plant Resources, Gyeongnam National University of Science and Technology, Jinju 660-758, Korea; and
4Department of Environmental Engineering, Chosun University, Gwangju, Korea.
Address for correspondence: Yong Sik Ok, PhD, Kangwon National University Chuncheon, Gangwon Korea; E-mail: firstname.lastname@example.org
Financial Disclosures/Conflicts of Interest: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science and Technology (2012R1A1B3001409) and by Korea Ministry of Environment as “GAIA (Geo-Advanced Innovative Action) Project. The Instrumental analysis was partly supported by the Korea Basic Science Institute, the Institute of Environmental Research, and the Central Laboratory of Kangwon National University in Korea.
Received April 12, 2012.
Accepted for publication October 29, 2012.