Tuesday, July 22, 2008

Black Eyed Susans, perovskia and dill with a Wardian case of sorts in the background.
Think Victorian passions, think pteridomania, think The French Lieutenant's Woman, think Queen Victoria's watercolors, Francis Kilvert's journal. Think ferns, think Wardian case, the first ever terrarium, invented in 1829 by a doctor who sought to protect his ferns from London's polluted air. Fast forward to the present and think about the role of Pteris vittata, the Chinese Brake Fern in detoxing hazardous waste sites. The process is called phytoremediation.
According to Environmental Protection Agency, 20, 000 fern plants are hard at work filtering arsenic from what was once an apple orchard in Crozet, Virginia where the trees were routinely sprayed with insecticides cointaining lead arsenate. The use of these chemicals was banned in 1970, but
" Today, there are still areas of the site contaminated with arsenic that poses an unacceptable risk to public, " says EPA's Myles Barto.
Rather than to rely the traditional method of digging up and disposing of the contaminated soil, the EPA opted for phytoremediation.
"Depending on weather and soil conditions, and the length of the growing season, each fern can extract up to 40-50 mg/kg arsenic from a square foot of soil." says Barto, adding that " The result is significantly less waste, perhaps one or two truckloads of waste, rather than 60 or 70 of soil. This technology has been used at several sites around the country but is still considered as an 'alternative' when it is compared to traditional techniques."

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