Heavy Metals: Soil Contamination and Its Remediation

Heavy metals are the most important soil contaminants in the environment. Heavy metals are the integrated components of the biosphere and thus occur naturally in soils and plants. Heavy metals (Cd, Cr, Cu, Hg, Pb, and Zn) have occurred widely as a result of human, agricultural and industrial activities which is responsible for the contamination of soils. Some of these metals are micro-nutrients that are necessary for plant growth, such as Zn, Cu, Mn, Ni, and Co, while others have unknown biological functions, such as Cd and Pb. Agricultural activities involve the addition of inorganic fertilizers, insecticides, pesticides, and amendments to the soil for increasing productivity are responsible for soil contamination/pollution. Water used for irrigation and the release of industrial effluents in water resources pollute the soil with solid wastes, heavy metals, and several other organic and inorganic substances. Reclamation of such contaminated soils through the phytoremediation method was found to be the cheapest and an effective method for extraction or removal of pollutants from contaminated soils.