Going Green: Phytoremediation
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Dr. Lee Newman of ESF Environmental and Forest Biology said, “Phytoremediation is the use of plants to clean up environmental contamination. We can use plants to take up and sequester heavy metals or in the case of these poplar trees to take up organic compounds and break them down into non-toxic by-products.”
Phytoremediation as a technology has been around for about 20 years and offers better alternative to the traditional landfill.
Dr. Newman said, “If you put something in a landfill, you are keeping it safe and not letting anything come in contact with it, which means whatever you put in there is staying in there. It’s not going away. With phytoremediation we have the plants which are actually breaking down the contaminants so it’s no longer a toxic chemical in the environment.”
In some cases, the trees can be harvested and safely turned into useful products.
“(At) one of our field sites in Oregon we harvested some of the trees and using the University of Washington’s papermaking machinery we had paper made and then tested to make sure none of the contaminants that we were cleaning up were in the paper and they weren’t. It was perfectly usable,” said Dr. Newman.
On the other hand, if the contaminant is a heavy metal like lead or chromium, phytoremediation offers a recycling opportunity.
Dr. Newman said, “We can reclaim that metal by harvesting the plants and extracting the metals from them completely removing the contaminants from the environment rather than putting them somewhere and keeping them for future generations to have to deal with.
Or the plants can be used to keep the contaminants right where they are.
“Alternatively you can use the plants to sequester the metals in the soil. So rather than take up the material, the plants are going to alter the soil chemistry to keep the metal in the soil in a non-biological form,” said Dr. Newman.
And through it all, the poplar tree is just doing what is does naturally.
“Absolutely. These plants are not engineered. They are not altered in any way but they have inherently in their make-up the ability to do this type of clean in the environment,” said Dr. Newman.