ABSTRACT
The processes that work to retard pollutant movement in soils include adsorption, ion exchange, chemical precipitation, and biodegradation. The fate of certain pollutants applied to the soil surface or introduced into the soil profile depends on an extremely complex combination of interactive processes. The effectiveness of these interactive processes depends on several variable conditions—the nature of the pollutant, the manner of its application, the fundamental nature of the soil, and its transient state at the time and place of interest. The Global Assessment of Soil Degradation study conducted for the United Nations Environment Programme found that in recent decades, nearly 11 percent of the Earth’s fertile soil has been so eroded, chemically altered, or physically compacted as to damage its original biotic function; about 3 percent of soil has been degraded virtually to the point where it can no longer perform that function.
