- The Washington Times - Sunday, January 20, 2002

A plant once believed to cure madness turns out to have a curative effect on soil contaminated by metal compounds that can cause cancer or birth defects. Alyssum, in the mustard family, is one of an increasing number of plants sought and studied worldwide for similar abilities and for commercial profit.
This metal-absorption process, called phytomining, uses plants during the natural process of plant growth instead of mining the metals through traditional industrial means to extract dangerous metals from the soil. The findings, by researchers at the University of Maryland and Sheffield University in England, were published in a report by the Department of Agriculture.
When the leaves have absorbed the metal to their maximum capacity, in a process called hyperaccumulation, growers harvest the crop, burn it for energy and recover the metal from the remaining ash. The net result of the process is a far higher concentration of metal than could be achieved through traditional mining processes.
According to phytomining pioneer Rufus L. Chaney, an Agricultural Research Service agronomist and lead author of the report, nickel is not typically available for mining until the soil contains 2.5 percent nickel. Burning the plants results in more than a tenfold increase in the metal remaining in the mass.
"The ash from our plants is 30 to 40 percent nickel," Mr. Chaney said. The chemistry involved in recovering the metal from the plant ash makes phytomining a relatively inexpensive and simple process. The contamination effects of traditional mineral extraction cannot be reversed naturally, but instead require the aggressive application of planned restoration programs, according to a report by the Manitoba Geological Survey.
The scientists say phytomining alters that scenario. "You can make money cleaning up contaminated soil from nickel," Mr. Chaney said, noting the resale value of the metal.
"Phytomining could be a profitable farming technology for land owners in California, Oregon and Washington," the Manitoba report said.
From 1 million to 2 million acres in the United States are potentially suitable for phytomining, the scientists said, although only 20 percent could be farmed economically. Mr. Chaney and his colleagues planted fields of alyssum in southwest Oregon and on the property of International Nickel Ltd., a smelter that operated until the mid-1970s in Port Colborne, Ontario, 30 miles west of Buffalo on Lake Erie. Viridian Environmental, a Houston-based company, cooperated in conducting lab, greenhouse and field demonstrations, he said.

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