Abstract

The efficacy of Moringa Oleifera, for the phytoextraction of heavy metals (Zn, Fe and Pb) in tropical soil was investigated. A randomized complete block design (RCBD) consisting of 3 blocks was used. Each block (A, B and C) was polluted with 100 mg Zn, Pb and Fe, respectively. Each block was subdivided into treatment and control of 5 replicates each. Two seedlings of M. Oleifera were planted in each treatment plot (phytoextraction) while no planting was done in the control. Zn, Fe and Pb, were analyzed for the soil and plant parts. Results show that M. oleifera was able to extract and accumulate high concentration of these metals (Zn, Fe and Pb) in their roots and shoots. The percentage reductions of the heavy metals in the soil were Zn (20.1%), Fe (22.7%) and Pb (64%) after 3 months of phytoextraction. The transfer factor was in the order of Zn > Fe > Pb while translocation factors indicate that metals were largely retained in roots. On the basis of the result obtained, M. oleifera, can be classified as hyperaccumulator of some measured heavy metals and therefore, it is suitable for phytoextraction of heavy metal (Zn, Fe and Pb) contaminated soils.

Key words: Heavy metal, contamination, Moringa oleifera, phytoextraction, translocation factor, transfer factor.