Clean gene trees. (Clippings).

Next spring, Richard Meagher plans to plant a new breed of trees in New Jersey and Indiana. The planting sites are contaminated with methylmercury, a toxic result of polluting shallow aquatic ecosystems with mercury. Meagher's University of Georgia research team spliced bacteria genes into cottonwood trees, enabling the trees to vaporize methylmercury into safer elemental mercury.

"The Environmental Protection Agency has been up against this problem of forcing people to do something about contaminated sites," says Meagher. "So this is a permanent solution to digging up a site and moving contaminated soil"--the usual, highly destructive, cleanup method.

Phytoremediation uses plants to cleanse pollutants from soil and water. Trees with long lives, deep roots, and strong thirsts (like cottonwoods or poplars) are popular with transgenic phytoremediation researchers--but not with Simon Harris of the Organic Consumers Association.

"The main concern about [genetically modified] organisms is that we're talking about organisms that have the ability to reproduce, so we need to be especially cautious," says Harris. The scientists' plans to plant only sterile, female trees and to harvest before pollination don't mollify Harris. "How will this new gene affect insects that may feed on the tree, or how will it alter the composition of other plants in the area?" he asks.

Others have taken an extremist approach to ending transgenic research. A University of Washington lab researching poplar genetics was fire-bombed in May 2001, although that particular lab was not actually doing transgenic work. Ironically, most researchers believe they are working on behalf of the environment.

Although University of Washington researchers asked for anonymity for fear of becoming terrorist targets, they continue working on engineering a hybrid poplar to clean up the widely spread groundwater and health hazard contaminant, trichloroethylene (TCE). "Another option is to increase the expression of the natural plant activity," says a Washington scientist. "We're trying to understand the mechanism that plants use to degrade TCE, so we can increase the activity of these plants through genetic engineering."

Come spring, the first transgenic trees will beat alternatives to the field. "Our transgenic trees will grow right through solid mercury sulfide, whereas wild plants only grow around these areas," says Meagher. "The trees mine the contaminant, and the wild plants come hack in." Continued monitoring in controlled sites hopefully will answer the questions that remain.