Narrator: This is Science Today. Over the years, thousands of sites in this country have been contaminated with trichloroethylene, or TCE. This solvent is a suspected carcinogen used in dry cleaning and industrial degreasers. Dr. Thomas Wood of the University of California, Irvine, is working to genetically engineer bacteria to carry an enzyme to degrade the solvent.

Wood: Our idea is to engineer bacteria that will hang out in the rhizosphere which is the area around the plant roots and the plant will feed those bacteria, so you don't have to add any nutrients at all. You also don't have to dig up the soil to treat the soil. The bacteria just continuously make this enzyme to get through trichloroethylene.

Narrator: Once perfected in the lab, Wood has long-term goals.

Wood: What we'd really like to do now is grow trees and take advantage of the bacteria that colonize tree roots to get rid of trichloroethylene. The tree we're shooting for is poplar tree, since it has roots that basically go from the surface down to the groundwater, covering all the soil between the surface and the aquifer and getting rid of TCE along the way.

Narrator: For Science Today, I'm Larissa Branin.