Organic chelate assisted phytoextraction of B, Cd, Mo and Pb from contaminated soils using two agricultural crop species

Abstract

This study was carried out to investigate the effects of adding different rates (0, 2.5, 5.0 and 10.0 mmol kg−1) of various organic complexifying agents (OCA) [ethylene diamine tetra acetate (EDTA), diethylene triamine penta acetate (DTPA), citric acid (CA), and humic acid (HA)] on heavy metal availability in the contaminated soils with 100 mg kg−1 B (H3BO3), 400 mg kg−1 Cd (CdCl2), 10 mg kg−1 Mo (Na2MoO4 2H2O) and 100 mg kg−1 Pb(NO3)2 and on the capacity of corn (Zea mays L.) and sunflower (Helianthus annus.) plants to uptake B, Cd, Mo and Pb in heated greenhouse conditions. Corn and sunflower plants were grown at 10,000 plants ha−1. Results indicated that OCA application increased heavy metal availability and uptake by plants. The capacity of OCA to release B, Cd, Mo and Pb in soils planted with corn and sunflower were HA>CA>EDTA>DTPA and HA>EDTA>CA>DTPA, respectively. Of the OCA tested, humic acid was the most effective in enhancing B, Cd, Mo and Pb uptake in both plant species. Significant differences were obtained in both species and plant parts. Plant species tested, sunflower was the most effective in uptake of B, Cd, and Mo. Root heavy metal uptake was greater than shoot heavy metal uptake in both species. As a conclusion, it can be said that humic acid facilitated B, Cd, Mo and Pb phytoextraction may provide effective soil decontamination strategy.