Phytoextraction of lead and chromium by leafy vegetables (lettuce, kale and swiss chard)

Abstract

Phytoextraction of metal from soil is a plant-based technique of removing metal pollutants from the soil. This research was carried out to assess the accumulation of Cr and Pb in leafy vegetables (lettuce, kale and Swiss Chard) in their harvestable part and root from artificially polluted soil with Pb and Cr. Soil physicochemical properties; pH, organic matter (OM), cation exchange capacity (CEC), Electrical conductivity(EC) and texture of the Soil sample under investigation was determined. S2 was more acidic and relatively great OM (5.48, 7.78) respectively than S 1 . Shoot part and root of Plant sample collected from green house grown in the control, contaminated and polluted with spinach extract soil was taken and dried in an oven at 70 0 c for 48 hrs. The grinded plant sample was digested by concentrated HNO3 and HClO4 (2:1) mixture. The digest was analyzed by FAAS. Results of the study indicate that Pb accumulation in shoot was on average greater (318.36 to 1235.20 mg/kg) in S 2 than S 1 (169.66 to 404.80 mg/kg). TF value of Swiss chard was generally higher in S2 than S 1 . Translocation of Pb from root to shoot was enhanced by the addition of spinach extract in kale and Swiss chard. TF and shoot accumulation of kale was enhanced by 36.5% & 33.3% respectively. Similarly Swiss chard TF and shoot accumulation was enhanced 8.3% &10.6% respectively with spinach extract. Chromium extraction by the three plants showed that translocation of Cr from root to shoot was limited. All TFs were less < 1 and these plants were able to accumulate less than 1000 mg/kg Cr except lettuce (1196.67 mg/kg) grown in PES2 . Lettuce without spinach extract amendment; kale with spinach extract; and Swiss chard with spinach extract and without spinach extract amendment could be used in Pb extraction in slightly acidic soil. In addition to this, kale with spinach extract and without spinach extract; and Swiss chard with spinach extracts could be used in Pb extraction in moderately acidic soils. Extraction of Cr was suitable by lettuces with spinach extract amendment in moderately acidic soil.