"The soil is the great connector of lives, the source and destination of all. It is the healer and restorer and resurrector, by which disease passes into health, age into youth, death into life. Without proper care for it we can have no life."
-Wendell Berry, The Unsettling of America:Culture and Agriculture
Soil is the upper layer of the unsaturated zone of the earth. This natural body is made of mineral and organic constituents, and is produced by solid material recycling and complex processes of solid crust modifications. Soil is a habitat for many organisms, is the living medium for plants, and the basis for agriculture. All animals depend upon soil, therefor, it is our jobs as humans to take care and clean the messes we have made, as the majority of soil contaminates are man-made. We see this in the increase in domestic waste, especially sewage sludge and its disposal to land, and the use of pesticides and fertilizers on farm crops, even in our backyards. One 40 pound bag of synthetic fertilizer contains the fossil fuel equivalent of about 2.5 gallons of gasoline according to the Environmental Protection Agency (EPA).
POLLUTANTS AND CONTAMINATION
In the larger picture the growing industrialization of the world has led to a considerable amount of soil degradation on a global scale. The extensive use of chemicals in industry has caused a great amount of soil becoming polluted with other substances, such as PAH (polyaromatic hydrocarbons, created when products like coal, oil, gas, and garbage are burned but the burning process is not complete), PCB (polychlorinated biphenyls, banned in 1979, used in many industrial applications due to their non-flammability, chemical stability, high boiling point, and electrical insulating properties), TNT (trinitrotoluene, a high explosive and is used as a reagent in chemical synthesis), and a other dioxins leading to contamination.
WHAT CAN BE DONE
Here are some techniques that can and are being utilized to decontaminate the soil:
Phytoremediation. This approach involves growing plants and trees and their associated microorganisms to stabilize or reduce contamination in soils. The pollutants are actually sucked up into the plant above ground, and then can be harvested and destroyed. Another approach uses Fungi. The fungi alters the makeup of the pollutants. Their mycelia grows in the soil, which has the effect of polluting the compounds and breaking them down into a safer state. More about this method can be read at: http://www.pollutionsolutions-online.com/articles/soil-remediation/18/erika_winquist_marja_tuomela_and_kari_steffen/bioremediation_of_contaminated_soil_with_fungi/1649/
Sources and further reading: