Removal of heavy metals from two agricultural soils in Abidjan, Cote d’ivoire using two plants species: Jatropha curcas and Vetiveria zizanioides

The study aims to investigate the removal of heavy metals, such as lead (Pb), cadmium (Cd), chromium (Cr), copper (Cu) and zinc (Zn) from contaminated soils using Jatropha curcas and Vetiveria zizanioides plant species. Soil samplings from the 0-20 cm depth were taken from two agricultural plots (Attécoubé and Cocody) in Abidjan, Côte d’Ivoire. The two plants species were planted in pots (25x25cm) containing 10 kg of soils. Samples were removed from pots for analysis, following 3, 6 and 9 months of growth. Physical and chemical characteristics of soil, such as: texture, cation exchanges capacity, pH, organic matter and heavy metals contents were measured before and after plant growth. Soil samples were air-dried and sieved through a 2-mm sieve according to NF X31-412. Samples were digested according to references methods used for the studies of marine pollution (UNEP). Metals were determined by atomic absorption spectrophotometer (AAS) and a Perkin Elmer 3000DV Inductively Coupled Plasma- Atomic Emission Spectrometer (ICP-AES). Results show that Vetiveria zizanioides and Jatropha curcas were effective heavy metal accumulators, making them useful in the phytoremediation of polluted soils by heavy metals. The accumulation of Pb, Cd, Cr, Cu and Zn in Jatropha curcas roots was found to be higher than those in leaves. However, in the case of Vetiveria zizanioides, Cu and Zn accumulated more in plant leaves than in roots. The results of this study clearly revealed that Vetiveria zizanioides was more effective than Jatropha curcas in reducing soil pollution by heavy metals.