Heavy metals are among the most significant freshwater pollutants and pose severe threats to geographical biodiversity. Pollution by heavy metals such as Cd, Pb, etc. not only affects the productivity of crops, but also compromises the quality of the atmosphere and water bodies. By propagation through the food chain, this type of pollution also threatens the health and life of animals and human beings. Such metals are not required for routine functioning of the human body and can be toxic even at low concentrations. The pollution caused by heavy metals is a long-term and irreversible process. Even though small concentrations of some metals (Ca, K, Mg, Na etc.) are required for routine functioning of the human body, their accumulation in higher concentration becomes toxic to most life forms. Certain trace metals such as Cu, Fe, Mn, Zn, etc., at catalytic amounts as metalloenzymes and as cofactors of enzymes, are essential to living organisms for their normal physiological activities. But a high concentration of Cu has been correlated with liver damage and Zn may produce adverse nutrient interactions with copper.