COMPARATIVE HEAVY METAL UPTAKE AND PHYTOREMEDIATION POTENTIAL OF THREE JATROPHA SPECIES

Abstract

The comparative metal uptake and phytoremediation capacity of Jatropha curcas, Jatropha gossypifolia, and Jatropha multifida in heavy metal contaminated soil from a dumpsite in Ibadan Nigeria were studied. Plants were transplanted into polythene pots containing 2kg of soil (control and dumpsite), using a 3×2 factorial laid out in complete randomized designed. Cu, Zn, Cr, Cd, Pb and Ni concentration was determined in the soil before planting and after harvesting as well as in the roots and shoots of the plant after 12 weeks using the standard method. The heavy metal levels in the control soil are within the permissible limits of WHO/FAO while only Cr and Ni in the contaminated soils are within the limit. The heavy metals concentration in the root of the plants ranged from 0.27-63.14 mg/kg (Cu), 4.82-54.18 mg/kg (Zn), 0.48-3.47 mg/kg (Cr), 1.75-72.37 mg/kg (Pb) and 0.05-3.23 mg/kg (Ni); in the shoots, the concentration ranged from 0.25-33.36 mg/kg (Cu), 5.40-12.48 mg/kg (Zn), 0.29-1.45 mg/kg (Cr), 0.58-8.26 mg/kg (Pb) and 0.05-3.23 mg/kg (Ni). Cd was not detected in the root and shoot of the three Jatropha species. Analysis of variance shows heavy metal uptake was influenced by the interaction of contamination level and Jatropha species. Bioaccumulation factor and Translocation factor ranged from 0.07-0.16 and 0.53-0.6 (Cu); <0.01-0.03 and 0.21-0.30 (Zn); 0.07-0.18 and 0.41-1.01 (Cr); 0.01-0.35 and 0.11-0.32 (Pb); <0.01-0.04 and 0.64-0.97 (Ni) respectively. More accumulation occurs in the root than shoot, therefore, Jatropha spp exhibit species variation in the uptake of heavy metals.

Keywords

• Jatropha species
• Phytoremediation
• Heavy metals
• Contamination.