Heavy Metals are defined as elements in the periodic
table having atomic number more than 20 or densities more
than 5g/cm3 generally excluding alkali metals and alkaline
earth metals. The environmental problems with heavy metals
are that they as elements are undestroyable and the most
of them have toxic effects on living organisms when
exceeding a certain concentration. Furthermore, some heavy
metals are being subjected to bioaccumulation and may pose
a risk to human health when transferred to the food chain.
Soils, whether in urban or agricultural areas represent a major
sink for metals released into the environment from a wide
variety of anthropogenic sources (Niragu, 1991).