Cadmium removal from Cd-contaminated soils using some natural and synthetic chelates for enhancing phytoextraction

ABSTRACT

The influence of a natural (citric acid) and two synthetic chelates (HEDTA, EGTA) on Cd phytoextraction with radish was studied. The experiment was conducted with Cd treatments including 0 (control), 5, 20, 60 and 100 mg Cd kg⁻¹ soil. When plants were fully developed, the designated HEDTA, EGTA and citric acid were applied to establish experimental treatments. Ten days after chelate applications, soil and plant samples were taken. Results indicated that synthetic chelates can considerably increase Cd concentration in soil solution compared with citric acid. Among the applied chelates, HEDTA provided more significant influences on soil solution. Cadmium concentration in both shoots and roots of radish was increased due to enhancing influence of chelate applications on Cd concentration in soil solution. Cadmium concentration in radish shoots was more than that of roots. This can be attributed to higher bioavailability and solubility of Cd in soil solution. In all treatments which received HEDTA, the cadmium concentration in both shoots and roots of radish was increased more than that of other applied chelates. Although HEDTA is more efficient in phytoextracting Cd than other chelates, due to durability of synthetic chelates toxic effects on soils, we recommend using larger amounts of light acids.

KEYWORDS:

• In situ remediation
• soil decontamination
• translocation factor

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Zahra Arabi is assistant professor in Department of Soil Science, College of Agriculture, Gorgan branch, Islamic Azad University, Gorgan, Iran.

Mehdi Homaee is professor in Department of Irrigation and Drainage, Tarbiat Modares University, Tehran, Iran.

Mohammad Esmaeil Asadi is assistant professor in Department of Agricultural Engineering Research, Agricultural and Natural Resources Research Center, Gorgan, Iran.

Safoora Asadi Kapourchal is assistant professor in Department of Soil Science, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran.