Phytoremediation of cadmium-polluted soils with Ipomoea asarifolia (Desr.) Roem. & Schult

Abstract

Phytoremediation is an alternative method for restoring soils polluted with heavy metals which is cost-effective and environment-friendly. The present study evaluated the potential of Ipomoea asarifolia to remediate  soils experimentally-amended with Cadmium. The plant was grown on soils amended with 0, 1500, 2000, and 2500 mg CdCl₂ salt. The salt was mixed with small portions of the soils and made upto 3kg salt/soil mixtures each. These were applied into 4 separate polythene-pots labelled; A, B, C and D respectively. Sample A containing 3kg non-amended soil (without Cd) served as the control. The concentrations of Cd applied to the soils were therefore; 0, 306.61, 408.82 and 511.02 mg//kg soils in the samples A-D respectively. Atomic absorption spectrophotometry (AAS) was used to analyse the bioaccumulation of Cd in the plant’s parts, over three harvesting phases of the study period. The results revealed that I. asarifolia is a good phytoaccumulator as it accumulated a total biomass of 0.23 ± 0.63, 272.85 ± 1.99, 377.40 ± 0.63 and 459.48 ± 0.60 mg/kg Cd from the amended soils A-D respectively. The Transportation Indices; RTI and STI for translocation of Cd to the plant’s stems and leaves were both greater than 1 (TI >1), indicating that the plant has a phytoextraction potential for Cadmium. These results therefore, suggest that I. asarifolia could be effective in phytoremediation of Cadmium-polluted environments.

Keywords: Heavy metals, cadmium, pollution, phytoremediation, Ipomoea asarifolia