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Environ Monit Assess (2014) 186:751759 DOI 10.1007/s10661-013-3414-x
The effectiveness and risk comparison of EDTA with EGTA in enhancing Cd phytoextraction by Mirabilis jalapa L.
Song Wang & Jianv Liu
Received: 28 December 2012 /Accepted: 5 September 2013 /Published online: 26 September 2013 # Springer Science+Business Media Dordrecht 2013
Abstract In the previous study, Mirabilis jalapa L. had revealed the basic Cd hyperaccumulator characteristics, but the accumulation ability was not as strong as that of other known Cd hyperaccumulators. In order to improve the accumulation ability of this ornamental plant, the chelants were used to activate the Cd in soil. As a substitute, ethylene glycol bis(2-aminoethyl) tetraacetic acid (EGTA) was selected to testify whether it has better effectiveness and can bring lesser metal leaching risk than EDTA. The data showed that the growth of M. jalapa was inhibited, while the Cd concentration of the plant was significantly increased under the treatments containing EDTA or EGTA. The Cd translocation ability under the EGTA treatments was higher than that under the EDTA treatments. The available Cd resulted from the application of chelant EGTA to the contaminated soils can be limited to the top 5 cm, while the application of chelant EDTA to the contaminated soils can be limited to the top 10 cm. In a word, EGTA showed better effectiveness than EDTA in enhancing Cd phytoextraction of M. jalapa. As an ornamental plant, M. jalapa has the potential to be used for
phytoextraction of Cd-contaminated soils and it can beautify the environment at the same time.
Keywords Cd . Mirabilis jalapa
L . Phytoremediation . EDTA . EGTA
Introduction
Excessive metal concentration in soils poses significant hazard to the environment, including plant, animal, and even human health. For example, the Cd concentration in some seriously contaminated sediments has exceeded 2,000 mg kg1 (Chen et al. 2003). Although a number of techniques have been developed to remove metals from contaminated soils, many sites remain contaminated because economic and environmental costs to clean up those sites with the available technologies are too high (Gunawardana et al. 2010). Phytoremediation has received considerable attention in recent years; it uses green plants to remove pollutants from the environment or to render them harmless (Weiss et al. 2006; Surat et al. 2008). This technique...