Comparative Study of Three Ornamental Plant Species for Their Phytoextraction Potentials of Cadmium Polluted Soil

Aim: A comparative study of three ornamental plants species in the remediation of cadmium polluted soil was investigated.

Duration and Place of Study: A 12 week phytoextraction trial was conducted at the Centre for Ecological Studies, University of Port Harcourt.

Study Design: 20 polythene bags (5 kg loamy soil each) were arranged in 4 batches (designated as A, B C and D) of 5 replicates each. Each bag was artificially polluted with 100 mg of cadmium solution (that is, 20 mg kg-1). Two seedlings of Moringa oleifera, Polyalthia longifolia and Aloe vera were transplanted from the nursery into batch A, B, C, respectively (phytorextraction treatments) while batch D had no planting (control).

Results: Moringa oleifera, Polyalthia longifolia, and Aloe vera showed 43.1%, 47.0% and 41.3% reductions of Cd in phytoextracted soil, respectively. The transfer factor was in the order of Aloe vera > Moringa oleifera > Polyalthia longifolia while translocation factors indicate that cadmium were largely retained in roots of Polyalthia longifolia and Aloe vera and in the shoot of Moringa oleifera. The suitability of the plants for phytoextraction was in the order of Moringa oleifera > Polyalthia longifolia > Aloe vera.

Conclusion: The three plants are suitable for the remediation of cadmium contaminated soils. Based on the experimental results, Moringa oleifera can be classified as Cd accumulator plant while Polyalthia longifolia and Aloe vera are Cd excluder plants.