Evaluation of some chelating agents on phytoremediation efficiency of Amaranthus caudatus L. and Tagetes patula L. in soils contaminated with lead

Abstract

This study was designed to evaluate the possible effects of some chelating agents on phytoremediation efficiency and plant growth parameters of Amaranthus caudatus L. and Tagetes patula L. in soils contaminated with lead. The plant species were grown in pots and treated with lead nitrate and in combination with 2.5, 2.0 and 2.5 mmol/kg of EDTA, SA and CA, respectively. The results showed that the highest accumulations of Pb (mg/kg) with 0.74 and 0.13 were found in the roots and stems of A. caudatus exposed to 400 mg/kg Pb containing EDTA and SA, respectively. Moreover, the highest accumulation of Pb in the roots and stems of T. patula with 0.87 and 1.5 mg/kg were observed in 400 mg/kg Pb- contaminated soil containing SA. Although the results obtained showed that T. patula would have a better phytoextraction potential than A. caudatus, it should be noted that due to the Pb behavior in the soil and/or leaching of Pb from the soil columns during the irrigation period the low amounts of Pb absorption by the root and aerial parts of the plants compared to the added doses of Pb(NO3)2 solution to the soil samples, imply the studied plants haven’t the adequate potential for phytoextraction of Pb from contaminated soils.