Conventional methods of dealing with soils contaminated with heavy metals are solidification
and removal. The most commonly used method is solidification. Solidification involves a
process in which the contaminated matrix is stabilized, fixated or encapsulated into a solid
material by the addition of a chemical compound such as cement. Although the metal
contaminants are chemically and/or physically bound to the matrix, they are not destroyed
(Alloway, et al. 1990). They are contained in such as way that leaching into the environment is
prevented or reduced (Roane, et. al 1996). Removal is the process of physically removing the
metal contaminated soil from the current site and discarding the waste into a designated
contaminated site. The removal of the contaminated soil is not cost effective and
environmentally safe (Grimski, et al. 1996).