Alpine pennycress doesn't just
thrive on soils contaminated with zinc and cadmiumit cleans them up by
removing the excess metals. Click the image for more information about
story to find out more.
Dainty Plant Can Power-Clean
Cadmium-Contaminated Soils By
September 10, 2004
Delicate, white flowers belie the ability of the small plant
called alpine pennycress to lift huge amounts of cadmium from contaminated
soil. Agricultural Research Service
agronomist Rufus Chaney, of the
Animal Manure and
By-Products Laboratory in Beltsville, Md., and a group of international
scientists have found the plant can concentrate about 8,000 parts per million
of cadmium in its leaves.
Cadmium is a naturally occurring element that is widely
distributed in the Earth's crust, but zinc mining and smelting wastes can cause
high cadmium contamination.
In 1992, the team of scientists from ARS, the
University of Maryland, the
University of Melbourne-Australia and
Massey University-New Zealand began
working with alpine pennycress (Thlaspi caerulescens), a plant capable
of accumulating vast amounts of cadmium and zinc in aboveground leaves and
stems. Using this plant, each year farmers could move soil metals into the
harvestable plant shoots, making it possible to gradually reduce the soil
concentration of cadmium to safe levels.
The cost of this remediation method, called phytoextraction, is
about $250 to $1,000 per acre per year, according to Chaney. The alternative
cleanup method--removal of contaminated soil and replacement with clean
soil--costs about $1 million per acre. Most highly contaminated soils can be
deemed safe after 10 years of phytoextraction, thus producing an effective
cleanup at a far lower cost.
In 2000, a patent was filed by the University of Maryland on the
use of alpine pennycress to remove cadmium from soil. No other similar
technologies currently exist for remediation of cadmium-contaminated soils
using plants. Cadmium phytoextraction using alpine pennycress has since been
licensed to Phytoextraction Associates, LLC, of Baltimore, Md., which will soon
conduct a commercial demonstration of the process.
Research is under way to develop a "super" phytoextraction
Chaney's research is
in the September issue of Agricultural Research magazine.
ARS is the chief scientific research agency of the
U.S. Department of Agriculture.