Phytoextraction of Pb, Cd, Cu and Zn by Ricinus Communis

Abstract

Nowadays, pollution problems have become very crucial. Anthropogenic activities are considered as the main sources of pollution carrying high concentrations of Metallic Traces Element (MTEs). These pollute the ecosystem and cause health problems. In order to contribute to the establishment of biological techniques to remedy this pollution and restore soil quality, the phytoremediation by Ricinus communis of soils polluted by the MTEs was considered. The soils were taken from the Komabangou area polluted by gold mining activities. They are distributed in pots and the seeds of Ricinus communis have been introduced. The crops are watered daily with tap water. After one month of culture, Ricinus communis in polluted soil showed less development than the same control plant grown in unpolluted soil. In fact, the lengths of the whole plant of Ricinus communis were 17 cm in polluted soil versus 35 cm in unpolluted soil. The lengths of the aboveground and underground parts of Ricinus communis were respectively 12 cm and 5 cm in polluted soil versus 12 and 25 cm in unpolluted soil. The only fact that Ricinus communis has developed in the polluted soil shows that this plant therefore has a tolerance and a resistance to the toxicity of the MTEs present in the polluted soil. Phytoremediation of MTEs by Ricinus communis showed that in the low polluted soil, Ricinus communis reduced by 4%, an initial Pb, Cu and Zn concentration of 61,309, 33,615 and 66,7030 mg / kg. In highly polluted soil, Ricinus communis reduced by 2.46%, 0.25%, 60.8% respectively an initial Pb concentration of 125 mg / kg, Cd of 0.58 mg / kg, Cu of 208.48 mg / kg. These results indicate that Ricinus communis is a plant species accumulating Pb, Cd, Cu and Zn metals and an excellent candidate for the phytoremediation of Cu and Zn and secondly that the accumulation of MTEs by this plant decreases when concentrations increase.