Cleaning Toxic Waste With Trees:

Using Hybrid Poplars to Clean Industrial Chemicals
From Water and Soil

Phytoremediation (from "phyto" for plant and "remediation" to correct a fault, pronounced fi-toh-re-mee-dee-a-shun) is the process of cleaning the environment using plants. Dr. Newman and Dr. Strand are growing poplar trees to see how well they remove chemicals from contaminated soil. Poplars work well because they grow very quickly, up to fifteen feet per year. Because they grow so fast, they need more water than most trees. They drink twenty-five gallons of water every day. Along with that water, they also suck up chemicals in the ground. Just like we change oxygen to carbon dioxide when we breathe, the trees change chemicals to less dangerous forms, then release the new chemicals from their leaves. After their peak growth spurt is over, the mature trees can be milled to make paper.

Hybrid poplar trees

There are a lot of chemicals that could be cleaned up using this method. Some of them are TCE (trichloroethylene), which was used by dry-cleaners, automobile garages, and mechanical industries; gasoline compounds; pesticides; and explosives.

In Oregon, researchers are testing how well poplars clean one of these chemicals in the environment. In 1984, a truck carrying trichloroethane, an industrial chemical, crashed and spilled the chemical on the ground. After scientists tried to clean the chemical out of the ground with other chemicals, in 1997 they decided to plant poplar trees to solve the problem. It will be a few years before scientists know if the trees can take the chemical out of the ground.

Dr. Newman and Dr. Strand studied how poplars clean the environment at the University of Washington (UW), where their work was funded by the Superfund Basic Research Program at the UW.

Dr Newman now works at the University of Georgia, in Athens, Georgia, where she continues to study ways to use plants for phytoremediation. She has a Bachelor’s degree in biology and chemistry, and a Master’s degree and a PhD in microbiology.

Dr. Strand is a professor at the UW College of Forest Resources. He has a Bachelor's degree in aeronatical enginnering, and a Master’s degree and a PhD in environmental engineering.