ABSTRACT
Soil is an important environmental component, functioning not only in the production of food and fiber but also in the maintenance of global environmental quality (Doran and Safley, 1997). In recent decades, almost 40% of agricultural land has been adversely affected by human-induced soil degradation as a result of intensive cultivation, overgrazing, land clearing, erosion, salinization, and chemical contamination (Sanders, 1992). Soil contamination by chemicals is becoming an increasingly dramatic concern to the environment. Most chemicals are of anthropogenic origin, arising from ore mining and smelting, combustion of fossil fuels, petrochemical processing, clectronic component manufacturing, pesticide and fertilizer industries, etc. (Adriano, 1986).
