feature article story in Agricultural Reseach magazine that includes a
section on phyto-mining.
plants like heavy metal!
"There's Metals in Them Thar Plants!" By
Miners might have been better off farming plants rather than
digging pits for high-grade ores.
U.S. Department of Agriculture
agronomist Rufus L.
Chaney and colleagues in USDA's Agricultural Research Service, at the
University of Maryland, and in England have
patented a way to use plants to "phyto-mine" nickel, cobalt and other metals.
Phyto-mining, or biomining, is the use of plants to extract
valuable heavy-metal minerals from soils.
One of the plants being used is alpine pennycress, a wild
perennial herb found on zinc- and nickel- rich soils in many countries. It--or
a high-yielding commercial crop like canola that had pennycress genes
incorporated into it--would be harvested and burned. Then the phyto-miners
would process these ashes and recover the valuable metals for sale.
Ashes of pennycress grown on a high-zinc soil in Pennsylvania
yielded 30 to 40 percent zinc, the equivalent of high-grade ore. Electricity
generated by the burning could partially offset costs.
Ironically, early prospectors in Europe used weeds such as alpine
pennycress as indicator plants to find metal ore. These plants thrive on soils
with high heavy-metal content, taking up metals through their roots and storing
them in their leaves to protect themselves from chewing insects and plant
USDA has signed a cooperative research and development agreement
with Viridian Resources, LLC, a technology company based in Houston, Texas. It
involves Chaney and colleagues associated with the patent as well as a
scientist at Oregon State University. An
article about the research appears in the June issue of Agricultural Research magazine
and on the web.
Scientific contact: Rufus L. Chaney, ARS
Laboratory, Beltsville, Md., phone (301) 504-8324, fax (301) 504-5048,