Gainesville, FL -- The solution to one of man's most vexing environmental problems may lie in one of nature's most remarkable plants.

In an article scheduled to appear Thursday in the journal Nature, University of Florida scientists report discovering a fern that soaks up arsenic from contaminated soil. The first plant ever found to "hyperaccumulate" arsenic -- a carcinogenic heavy metal often used as an herbicide -- the fern may prove useful in cleaning up thousands of sites contaminated by arsenic from industrial, mining, agricultural or other operations around the world.

"It has great potential for remediating these contaminated soils," said Lena Ma, an associate professor at UF's Institute of Food and Agriculture Sciences and lead researcher on the project. Ma's research team found that the brake fern, Pteris vittata, not only soaks up arsenic but does so with staggering efficiency. They measured levels as much as 200 times higher in the fern than the concentrations in contaminated soils where it was growing, Ma said.

In that example, from a site contaminated by lumber treated with chromium-copper-arsenic solution, the soil had 38.9 parts per million of arsenic, while the fern fronds had 7,526 parts per million of arsenic.

In greenhouse tests using soil artificially infused with arsenic, concentrations of the heavy metal in the fern's fronds have reached 22,630 parts per million -- meaning that a startling 2.3 percent of the plant was composed of arsenic, Ma said.

To their surprise, the research team found the fern even accumulates arsenic in soils that contain normal background arsenic levels of less than 1 part per million. For example, the team measured 136 parts per million of arsenic in fronds of a fern growing on UF campus in soil that contained just .47 parts per million of the metal.

Levels of arsenic in the plant easily eclipse the threshold of 5 parts per million for classification as an industrial-leve
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Contact: Lena Ma
lqma@ufl.edu
352-392-9063
University of Florida
30-Jan-2001