COMPARISON OF EDTA AND EDDS ENHANCTED PHYTOEXTRACTION OF Cr AND Pb FROM CONTAMINATED SOIL BY ANANAS COMOSUS (L.) MERR.

Abstract

The effects of chelating agents on Chromium (Cr) and lead (Pb) absorption were studied by planting pineapple, Ananas comosus (L.) Merr. in contaminated soil. All plant samples were grown in a nursery for 30 days and then separated into seven sets: Set (1) had nothing added (Blank); (2) had Pb added as Pb(II) Nitrate (Pb(NO₃)₂) at 500 mg kg^-1 soil; (3) added Pb(II) nitrate and EDTA, a chelating agent; (4) contained both Pb(II) nitrate and EDDS, a second chelating agent; (5) only added Cr as potassium dichromate (K₂Cr₂O₇), at 400 mg kg^-1 soil; (6) was treated with Cr (potassium dichromate) plus EDTA; and (7) contained both Cr (potassium dichromate) and EDDS. The chelating agent concentrations were 2 millimoles per kilogram soil. Soil and plant contamination levels were measured by analyzing the Cr, Cr(VI) and total Pb after growing for 30, 60, 90 and 120 days. The analysis divided the plant samples into two parts: Aboveground and underground. Plant growth was also analyzed by dry weight, root length and expression of toxicity through withered leaves and yellow leaf symptoms. The results of this study indicate that after 60 days, the EDTA agent had the highest Pb absorption efficiency, with the plant sample absorbing 288.14 mg Pb per kg soil in the aboveground part and 796.66 mg kg^-1 soil in the underground part. The EDTA agent had high Cr absorption efficiency, with the plant sample absorbing Cr at 545.72 mg kg^-1 soil in the aboveground part and 2267.99 mg kg^-1 soil in the underground part after 90 days. The EDTA and EDDS agents did not affect pineapple growth and expression of toxicity symptoms were statistically significant (p≤0.05) compared with the control sets.