Scientists ramp up ability of poplar plants to disarm toxic ...( Scientists since the early '90s hav...)

Scientists since the early '90s have seen the potential for cleaning up contaminated sites by growing plants able to take up nasty groundwater pollutants through their roots. Then the plants break certain kinds of pollutants into harmless byproducts that the plants either incorporate into their roots, stems and leaves or release into the air.

The problem with plants that are capable of doing this is that the process is slow and halts completely when growth stops in winter. Using plants in this way, a process called phytoremediation, often hasn't made sense given the timetables required by regulatory agencies at remediation sites.

Scientists led by the University of Washington's Sharon Doty, reporting in this week's Proceedings of the National Academy of Sciences, say that genetically engineered poplar plants being grown in a laboratory were able to take as much as 91 percent of trichloroethylene, the most common groundwater contaminant at U.S. Superfund sites, out of a liquid solution. Unaltered plants removed 3 percent. The poplar plants all cuttings just several inches tall growing in vials also were able to break down, or metabolize, the pollutant into harmless byproducts at rates 100 times that of the control plants.

While federal regulations allow the growing of transgenic trees in greenhouses and controlled field trials for research purposes, they do not allow the commercial growing of transgenic trees. A transgenic plant is one in which its genetic material is manipulated. Sometimes only its own genetic material is altered and sometimes genetic material is added from other plants, bacteria or animals.

The work being published this week raises the interesting question of the potential for using transgenic trees on sites where toxic plumes of pollutants are on the move in groundwater.

"Small, volatile hydrocarbons, including trichloroethylene, vinyl chloride, carbon tetrachloride, benzene, and chloroform, are common environmenta
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