The enhancement effects of EDTA, citric acid and NTA on phytoremediation of vermicompost enriched with high Cu and Zn contents

Pot experiments were conducted to investigate the effects of three different chelating agents(EDTA, citric acid, NTA) that intensify the absorption and accumulation of Cu, Zn in vermicompost for Euchlaena Mexicana Schrad. The results indicated that chelating agents addition could inhibit the growth of Euchlaena Mexicana Schrad, and the inhibition on the roots is greater than the shoots. At the same concentration, EDTA had the greatest inhibition on plant roots, the overarching inhibition on plant shoots fell to citric acid. The addition of EDTA and NTA increased Cu or Zn contents in the roots and shoots of Euchlaena Mexicana Schrad, and also improved the Cu or Zn accumulations in the shoots, although high addition concentration of CA increased Cu or Zn contents in the roots and shoots of Euchlaena Mexicana Schrad, Cu or Zn accumulations in the shoots were conspicuously inhibited after high concentration of CA were added. Hence, EDTA and NTA have the potentials of intensifying the extraction of Cu or Zn by Euchlaena Mexicana Schrad from the vermicompost enriched with high Cu or Zn contents, which opens up a new approach to enhance phytoremediation in terms of solid waste contaminated with heavy metals.