This is Steve Ember with the VOA Special English AgricultureReport.
Poplar trees can be cut down and used for wood or paper. Or theycan be left to stand and also used for different purposes. Poplartrees are often used to guard against water pollution. They areplanted as barriers to keep waste from entering groundwater andrivers.
Their large root systems trap waste, like nitrogen-basedfertilizer, and help reduce the loss of soil. Now, poplar trees maybecome important tools for cleaning the environment. Some scientiststhink poplars can be a valuable resource to remove poisonoussubstances from the soil.
The poplar tree is found in many places in the northern half ofthe world. It is a fast growing tree that requires a lot of water.Different kinds of poplar trees are native to Asia, Europe and NorthAmerica. In the United States, poplars are also known as cottonwoodtrees.
For years, Professor Richard Meagher of the University of Georgiahas done research on genetically engineered plants. He is nowtesting a poplar tree that has been genetically engineered to takein mercury through its roots. The tree then slowly releases themercury into the air through its leaves.
Mercury is a highly poisonous metal. It is a waste product ofmany industries. Mercury builds up in fish and other living things.It is especially dangerous to the development of children. This iswhy women who might get pregnant are warned to be careful aboutmercury levels in the food they eat.
Professor Meagher is testing his genetically engineered poplarson some land in Danforth, Connecticut. The ground is polluted withmercury from a factory once there. The scientist has planted onehundred sixty poplars to remove the pollution.
Not everyone likes the idea to use genetically engineered treesto collect mercury. Critics say these could reproduce with wildtrees or displace them. Another criticism is that the poplars onlyspread mercury rather than remove it from the environment. Theprofessor says it is better to spread the mercury than have it allin one place where it could be more of a health risk.
Still, there is great interest in using plants to process andcontrol harmful substances. And poplar trees are among the moststudied.
But using poplars as a natural barrier against water pollution isnot a new idea. The Chinese have used them this way for thousands ofyears.
This VOA Special English Agriculture Report was written by MarioRitter. This is Steve Ember.