August 1, 2005 Planting ferns can be a cheaper, greener way to soak up poisons such as arsenic from the soil. Ferns absorb arsenic through their roots and store it in their leaves, which can then be cut off. Arsenic -- once used to treat wood -- can still lurk in old roofs, decks, and playgrounds.
DULLES, Va.--There could be dangerous chemicals lurking in your own backyard, putting you and your family at risk. The harmful chemical arsenic, once used to treat lumber, and now primarily used in pesticides, can make its way into the ground and linger for decades, turning clean soil into tainted dirt. Now, scientists are getting down and dirty with a new way to clean it up.
James Riordon has spent years enjoying his deck. But like many homeowners, he was shocked to hear harmful chemicals hidden in the wood could be a health risk for his family. "I'm surprised to learn that there could be arsenic in a deck that my son has been exposed to for almost a decade," he says.
Although arsenic is no longer used to treat wood, the chemicals from older wood decks and playgrounds may have seeped into the soil. The polluted soil can be dug up, but it's costly.
"What we're looking for is an additional option for reducing arsenic levels, one that is more environmentally friendly, one that's more economical, and one that's more pleasant for the residential homeowners," says Edward Hughes, an environmental engineer at the U.S. Army Corps of Engineers in Baltimore.
Now, soil chemists have a new, cheaper, greener way to soak up buried backyard chemicals, fern plants.
Soil chemist Michael Blaylock, of Edenspace Systems Corporation in Dulles, Va., says, "We know that plants are very good at taking things out of soil. That's what roots do; they take elements and nutrients out of the soil."
The ferns clean up contaminated soil by a process called phytoremediation. A contaminant -- like arsenic -- is absorbed through the plant's roots. The arsenic then moves up to the leaves where it's stored. The leaves can then be cut off.
"The whole key is being able to concentrate the arsenic in the plant," Dr. Blaylock says.
Now homeowners like Riordon can grow ferns under their decks and let these hard-working plants do the dirty work.
Also at risk are people living on former farmland that once used pesticides. Homeowners should get a soil tester and check the arsenic levels. If you want to buy soil test kit or arsenic eating ferns, go to Edenspace.
BACKGROUND: The edenfern soil cleanser is a fern that extracts arsenic from soil, waste, or water and stores the arsenic in its fronds, where it can't damage the environment. It can store 200 times as much arsenic as other plants. The fronds are then harvested for disposal.
THE PROBLEM: Residues from old pesticides, gardening chemicals, and treated lumber can stay in the soil for years. These residues often contain arsenic, posing a significant health hazard. In the past, arsenic could only be removed by digging up the soil itself and depositing it in a landfill.
THE SOLUTION: Planting ferns is a much less expensive and more convenient approach than digging up vast pieces of land. In 2004, about 2,800 edenfern plants were installed at 14 test sites in Washington, D.C. The plants removed about 9 parts of arsenic per million parts of soil across all the sites in the first year. Before, the soil held between 16 and 127 parts of arsenic per million parts of soil. The project's scope is being expanded to plant 10,000 ferns at up to 35 sites.
WHAT IS ARSENIC: Arsenic is a semi-metallic chemical that is difficult to detect because it has no odor or flavor. It can kill humans quickly if consumed in large amounts -- it was once a popular poison -- and even long-term exposure to small doses can be unhealthy. Arsenic causes cancer, mutations and birth defects, and has also been associated with the development of diabetes. Once used as an embalming fluid in the 19th century, arsenic was also widely used in insecticides, and as a component in wood preservatives in lumber and furniture. Decades after arsenic is introduced into the environment, soil concentrations can be hundreds of times higher than the residential standard in many states.
ON THE WEB: The edenfern soil cleanser can be purchased from Edenspace.