The world has been witnessing serious environmental changes especially since the dawn of industrialization. Global industrial revolution has led to the release of unprecedented amount of toxic substances (pollutants) into the environment. Natural degradation of pollutants is becoming increasingly difficult due to the quantity, complexity and heterogeneity of pollutants released into the environment. One of such ubiquitous, toxic and recalcitrant pollutant of concern is heavy metals. Examples of heavy metals includes cadmium (Cd), iron (Fe), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), lead (Pb), zinc (Zn), arsenic (As), manganese (Mn), nickel (Ni), selenium (Se) and the platinum group metals, which comprises platinum, palladium, rhodium, ruthenium, osmium, and iridium. There are two major sources through which heavy metals enter into the environment namely natural sources and anthropogenic or man-made sources.