Appraising the role of environment friendly chelants in alleviating lead by Coronopus didymus from Pb-contaminated soils

- Two eco-friendly chelants, A. molybdate and EDDS were compared for Pb accumulation and extraction by C. didymus.
- Evaluation of Pb uptake and accumulation, biomass yield, photosynthetic activity, were the criteria for comparison.
- C. didymus accumulated Pb more in roots than shoots.
- EDDS was more effective in solubilising and mobilising Pb than A. molybdate.
- C. didymus showed good efficacy to remediate Pb-contaminated soils.

In a screenhouse experiment, we investigated the role of two environment friendly chelants, Ammonium molybdate and EDDS for Pb mobilisation and its extraction by Coronopus didymus under completely randomized controlled conditions. Seedlings of C. didymus were grown in pots having Pb-contaminated soil (1200 and 2200 mg kg−1) for 6 weeks. Plants were harvested, 1 week after the addition of A. molybdate and EDDS. Results revealed that A. molybdate and EDDS enhanced the uptake and accumulation of Pb in roots and shoots of C. didymus. At 2200 mg kg−1 Pb level, compared to Pb-alone treatment, the maximal concentration of Pb was increased upto ∼10% and ∼19%, in roots whereas ∼8% and ∼18%, respectively, in shoots on addition of 2 mmol kg−1 A. molybdate and EDDS. Additionally, Pb + EDDS treatments enhanced the plant biomass and triggered strong antioxidative response, more efficaciously than Pb + A. molybdate and Pb-alone treated plants. In this study, EDDS relative to A. molybdate was more efficient in mobilising and extracting Pb from soil. Although, EDDS followed by A. molybdate had good efficacy in mitigating Pb from contaminated soils but C. didymus itself has the inherent affinity to tolerate and accumulate Pb from contaminated soils and hence in future, can be used either alone or with some other eco-friendly amendments for soil remediation purposes.

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