Brake Fern Is A Powerful Heavy Metal "Quicker-Picker-Upper"
Phytoremediation. It may sound like what happens when a neutral party intervenes to restore broken communication channels between a houseplant and its owner. Or a rigorous re-education process for
wayward tropical vines.
But the use of natural plants to clean up polluted environments is unfolding as a promising strategy for "un-doing" the damage to Nature - including the human body - spurred by years of accumulated toxic waste.
Recently, researchers from the University of Florida and the University of Georgia found that a fast-growing fern may help clean up soil contaminated by arsenic. The hardy perennial may someday help to alleviate the health threat posed by one of the most powerful, widespread, and potentially carcinogenic heavy metals currently contaminating U.S. soil.
Even when grown in normal soil, the brake fern (Pteris vittata) sucks up arsenic at a rate 17 times greater than that of other plants. But the researchers found that brake ferns growing wild on a contaminated waste site in central Florida increased their toxic appetites even further, with fronds hyper-accumulating arsenic at average levels over 100-fold higher than in normal soil - at no harm to the plant! In fact, after growing for six weeks in an experimental soil laced with ultra-high arsenic levels, the fern's composition exceeded 2% arsenic with nary a wilt.
For this reason, the brake fern "has great potential to remediate arsenic-contaminated soils cheaply," the researchers concluded. Once the ferns scour the soil, their arsenic-rich fronds could be transported to a special waste facility for disposal.
Such an innovative solution is desperately needed. At the moment, arsenic soil contamination in the U.S. represents an environmentalist's nightmare. In Florida alone, there are 3,200 sites contaminated by arsenic, mainly because of its use as a pesticide in the early 1900's by cattle ranchers. Arsenic is also commonly used as
a weed-killer on golf courses and lawns and is a by-product of mining, milling, wood treatment, and combustion processes.
Ma LQ, Kmar KM, Tu C, Zhang W, Cai Y, Kennelley ED. A fern that hyperaccumulates arsenic. Nature 2001;409:579.
Hoover A. UF research: Plant soaks up deadly arsenic from soil. Jan. 30, 2001.University of Florida News and Events, available on the UFL website: http://www.napa.ufl.edu/2001news/fern.htm
Researched, written, and edited by Eddy Ball, Editor, Patrick Runkel, Associate Editor, and Scott Holmes, Contributing Medical Writer. Please send comments and suggestions to firstname.lastname@example.org