CNN Environment News

Flower power

Plants recruited to clean up toxins

April 27, 1996
Web posted at: 7:32 a.m. EDT

From Correspondent Mary Ann McRae

TRENTON, New Jersey (CNN) -- Can plants rid the earth of radioactive waste and toxic metals? Yes, say some researchers.


Ilya Raskin of Rutgers University says plants can help clean up hazardous waste sites through a process of phytoremediation. "Phytoremediation is the use of plants to remove contaminants from the environment and to render them harmless, as simple as that," he says.

But it's not as simple as just putting a plant in the soil, Raskin says. It requires coaxing the plant into soaking up pollutants instead of nutrients. It also requires the right kind of plant, with the right kind of roots.

Plant testing

Rutgers, along with a small New Jersey company -- Phytotech -- is field testing sunflowers in the polluted ponds near the Chernobyl nuclear plant.

"Using these plants, we will be able to remove radioactive nuclides from the water and make it clean for irrigation purposes or even as a source of drinking water," says Slavik Dushenkov of Phytotech.

Researchers are also excited about the Indian mustard plant, which they say is particularly handy at extracting toxic metals from the soil.


"Growing plants is inherently cheaper, safer, friendly, acceptable to environmental agencies," Raskin says. "It's very cost-effective technology for soils, because really the technology which is in existence now prevents us from cleaning up most of the sites we have."

Researchers are looking at an old factory in Trenton that has high levels of lead and is smack in the middle of a residential neighborhood.

The conventional cleanup would mean digging up the lead-polluted soil and dumping it in a landfill, and could cost $600,000. By using Indian mustard plants to suck up the lead, the costs, researchers say, could be 10 times less.


"The roots of these plants generally will go down at least 12 inches, (sometimes) as much as 20 inches," says Phytotech soil chemist Michael Blaylock. "The good thing for the plants is that the lead stays mostly in the top six inches of the soil."

"If this works, yeah, it's wonderful. But if it doesn't work, hopefully, they will go back to the old way, whatever it takes to get it cleaned up," says James Rolling, who lives near the factory.

But researchers hope they won't have to resort to the old way. Field trials have yielded positive results and a handful of companies hope to commercialize this plant technology.

"You have to remember that the best biochemists on the planet are probably organisms," said Paul Mankiewicz, of the Gaia Institute, which works on environmental issues. "Plants are way up there."

If nature proves able to do the job over time, it will provide a cheaper -- and certainly, much prettier answer -- to environmental cleanup.


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