Enhancing cadmium phytoremediation in contaminated soil using sunflower (Helianthus annuus L.) with EDTA and vermicompost amendments

Abstract

The study hypothesis posits that EDTA, an effective chelating agent, can effectively mobilize cadmium from soil, augmenting the sunflower's natural ability to absorb and sequester heavy metals. Concurrently, vermicompost, rich in organic matter and beneficial microorganisms, enhances soil health and supports plant growth, thereby fortifying the sunflower's phytoremediative potential. The pot experiment was carried out as an overall completely randomized design (CRD) at the Sheila Dhar Institute (SDI) experimental farm, University of Allahabad, Prayagraj, in the Kharif season during the years 2023-2024. Plants were cultivated in pots with soil (5 kg) that contained varying concentrations of Cd (0, 15, 30, and 50 mg/kg), vermicompost (0 and 10 g/kg), and EDTA (0 and 2.5 mmol/kg). Plants were also cultivated in containers with clean soil (T1) as control treatment. For analyzed heavy metal (Cd) in plants with a tri-acid mixture (15 ml) containing concentrations of HNO3, H2SO4, and HClO4 in 5:1:2 ratios, use the Atomic Absorption Spectrophotometer (AAS). The result showed that the combined Treatment (T3) pot of application of Cd 0+ EDTA (2.5 mmol/kg) and vermicompost (10 g/kg) was the maximum dry biomass (14.43 g/pot) of the sunflower plant. While the maximum dose combined treatment (T12) application of Cd 50 mg/kg+ EDTA 2.5 mmol/kg and vermicompost 10 g/kg is greater than before, the maximum accumulation of Cd in the shoot and root of Helianthus annuus L. by shoot 37.16% and root 31.16%, respectively as compared to the control treatment pot Cd-50. The results indicate that the combined application of EDTA and vermicompost significantly increased cadmium uptake by sunflowers compared to untreated controls, demonstrating their synergistic effect in improving phytoremediation efficiency.