Phytoremediation
http://en.wikipedia.org/wiki/Phytoremediation
http://www.unep.or.jp/ietc/publications/freshwater/fms2/1.asp
In
the phytoremediation, process certain plants and trees are planted, whose roots absorb contaminants from
ground water over time, and are harvested and destroyed. This process can be
carried out in areas where the roots can tap the ground water. Few examples of
plants that are used in this process are Chinese Ladder fern Pteris vittata, also known as the brake fern, is
a highly efficient accumulator of arsenic. Genetically altered cottonwood trees are good absorbers of mercury and transgenic Indian mustard plants soak up selenium well
Phytoremediation
refers to the natural ability of certain plants to degrade,or render harmless
contaminants in soils, water, or air. Contaminants such as metals, pesticides,
solvents, explosives,[1] and crude oil and its derivatives, have been
mitigated in phytoremediation projects worldwide. Many plants such as mustard
plants, alpine pennycress hemp and pigweed have proven to be successful at
hyperaccumulating contaminants at toxic waste sites.
The
uptake of contaminants in plants occurs primarily through the root system, in
which the principal mechanisms for preventing contaminant toxicity are found.
The root system provides an enormous surface area that absorbs and accumulates
the water and nutrients essential for growth, as well as other non-essential
contaminants. Researchers are finding that the use of trees is effective in treating
deeper contamination because tree roots penetrate more deeply into the ground.
In addition, deep-lying contaminated ground water can be treated by pumping the
water out of the ground and using plants to treat the contamination.