Project Summary (1995-2000)

The objective of this project is to determine the ability of plants to remediate toxic waste sites. In prototype experiments, the ability of poplar trees to detoxify trichloroethylene (TCE) will be examined. Poplars are able to grow in the presence of high levels of TCE and to transpire and metabolize the compound. TCE is converted to trichloroethanol, trichloroacetic acid, and two polar compounds whose structures are being determined. Researchers are determining which clones metabolize the largest proportion of TCE absorbed by the plants. The extent of metabolism is being augmented by introducing genes which are known to metabolize TCE. The best clones are being studied in greenhouse-scale experiments to determine their ability to adsorb and detoxify TCE. Finally, field studies are being conducted in collaboration with the Occidental Chemical Corporation at a site at the Port of Tacoma. In conjunction with these studies, a collaborative study is determining the effect of the ingestion of TCE-treated poplar tissue on insects that normally feed on poplar. These insects in turn are being fed to starlings or their chicks to determine whether there is any effect on the birds resulting from this exposure. Development of an experimental biomarker for detection of below-ground TCE contamination is also being investigated.