Phytoremediation is the environmentally friendly science of using plants and trees to remove heavy metals and other toxins from contaminated soil. By planting specific plants and trees, called hyper-accumulators, in polluted areas, the contaminants can be reduced.
The science is simple, and basic to plant life.
Toxins can enter the soil through a multitude of paths, from chemical fertilizer applications to urban runoff. The toxins can then become embedded in the Earth and are considered bio-accumulates. These bio-accumulates may include metals, pesticides, solvents, explosives, crude oil and its derivatives.
As the remediating plant grows, it develops a root system. The roots draw the bio-accumulates along with beneficial nutrients as part of its nourishment, and concentrate them in its stems, shoots, and leaves, which can then be harvested and disposed of safely.
The marvel is how the plants can flourish while simultaneously rendering the toxins harmless through the nutrient uptake process, resulting in clean, balanced and nutrient rich soil, which can then be safely used for agriculture or improving the wildlife habitat.
Mustard, alpine pennycress, and pigweed are all phytoremediators, but one particular plant shows potential above the rest; Hemp.
Hemp’s industrial uses in the production of food, fuel, and fiber are widely documented, but few people are aware of Hemp’s potential as a remediator. Why is Hemp superior to other phytoremediators? Hemp grows quickly, reaching full harvest in just 180 days and produces a root ball extending into the ground from 6 to 8 feet. At that level, toxins can be extracted without the need to remove any of the contaminated top soil, thus avoiding the expense of transportation to offsite disposal facilities. Other factors making Hemp the champion of remediates are its ability to grow unaffected by the toxins it accumulates, its fast rate of absorption and its ability to bind compound contaminants from the air and the soil. Hemp actually removes CO2 from the air as it removes heavy metals and other pollutants from the soil.
Read complete article here:
http://www.hemp.com/2012/06/soil-contamination-phytoremediation-with-hemp/