Effect of chelating agents on increasing of lead accumulation in raddish (Raphanus sativus L.)

In this study the effects of synthetic chelators (HEDTA، EGTA) and low molecular weight organic acids (LMWOA) such as citric acid on Pb solution in soils that artificially contaminated also Pb phytoextraction capability by raddish (Raphanus Sativus L.) were investigated. The experiment was carried out in a randomized complete factorial design with three replications. Concentration treatments of lead using PbCl2 were 0 (control)، 50، 100، 600 and 1000 mg Pb kg-1. After plants complete growth، 1. 5، 5 and 6 mMkg-1 soil HEDTA، EGTA and Citric Acid were added per pot، keeping a control without any chelator application. To determine the amount of lead contaminants، soil and plants samples were taken from the pots 10 days after adding chelates and lead concentrations were determined. The results showed that in all treatments the concentration of soluble lead in soil was higher than control. Also، synthetic chelators as compared with LMWOA (Citric Acid) has increased solution remarkably. Among the other chelates HEDTA had significant effects on Pb solution. In current study Pb concentration in shoot and root of Raphanus Sativus were increased significantly after addition of HEDTA as compared with other chelates. In addition، Pb concentration in roots of raddish were higher than those in shoots.