A comparative study on the efficiency of biodegradable EDDS and micro-electric field on the promotion of the phytoextraction by Commelina communis L. in Cu-contaminated soils

Phytoextraction has been considered as an attractive option technique for the remediation of heavy metals contaminated soils. In this study, Commelina communis L. (Control), and plant with EDDS (5 mmol kg− 1) or micro-electric field (0.5 V cm− 1) was performed to treat Cu-contaminated soils spiked by Cu content of 0, 100, 200, 400, 600 mg L− 1. Compared with the Control system, when biodegradable chelant of EDDS or micro-electric field were applied into treatments, the concentration of accumulated Cu, increased by 15%-47%, and 65%-79%, respectively, in the shoots of plants. While it increased by 16%-86% and 28%-38%, respectively, in the roots of plants. Highest Cu accumulation in shoot and root of plant under micro-electric field was 78.7 and 2068.9 mg kg− 1. In addition, copper was strongly inhibited the growth and metabolism under a higher Cu concentration (> 200 mg L− 1) due to the disorder of water and nutrients acquisition and use. Hence, the enzyme activities (MDA and POD) of leaves and the concentrations of soluble carbohydrate significantly increased with the application of EDDS or micro-electric filed compared with the Control system. These results indicate that the use of micro-electric field is more effective treatment for the remediate the Cu-contaminated soils compared with the biodegradable chelant of EDDS.