Effect of EDTA on phytoremediation of copper-polluted soils

Efficiency of additive agents was studied to remove copper from Cu-mixed soils by Brassica juncea and Zea mays L. The plants were grown in decomposed granite soil (Regosol) and volcanic ash soil (Andosol) for 3 weeks. To simulate actually-contaminated soil, copper contents of 25mug Cu g(-1) and 250mug Cu g(-1) were prepared for Regosol and Andosol, respectively. EDTA was found to be an excellent additive agent to raise the availability of Cu in soils. The effect of EDTA on Cu absorption by plants was limited in Regosol. On the other hand, in Andosol the Cu accumulation in shoot of Z. mays for the 100 ram EDTA treatment were 3.7 times larger than that for the 0 mM EDTA treatment. The Cu absorption by B. juncea was not affected by the EDTA addition to Andosol. These results suggest that the effect of EDTA on the Cu absorption by plants significantly changes with the additive concentration and with the types of soil and plant.