BY JEFF DONN
A common fern has been found to soak up extraordinary amounts of arsenic without any
ill effects, potentially offering a natural way of cleaning up polluted soil and water.
The plant, known as the brake fern, grows naturally in the Southeast and California.
``It looks lush green,'' said Lena Ma, a soil chemist who led the research at the
University of Florida.
``When I take people to my greenhouse to look at a fern with 8,000 parts per million of
arsenic, they can't imagine it's toxic waste.''
The brake fern, whose scientific name is Pteris vittata, is the first plant known to
accumulate arsenic in extremely high concentrations and still flourish, scientists said.
The discovery is reported in today's issue of the journal Nature.
The Florida researchers were looking for a plant that could take in soil arsenic in
high concentrations and then be hauled away. They tested 14 species from an abandoned
lumber yard contaminated by arsenic in Archer, near Gainesville.
Their tests showed that the brake ferns growing there concentrated as much as 200 times
the arsenic level in the soil. In other tests, the researchers spiked soil with varying
levels of arsenic and found that brake ferns absorbed the poison at 10 to 64 times the
Arsenic taints many sources of drinking water in the United States and abroad. People
who drink arsenic-contaminated water over long periods are believed to run a higher risk
of bladder, lung and skin cancer, as well as other heart and lung ailments.
Some arsenic is naturally present in soil.
It also comes from some farm chemicals, wood preservatives and other industrial
Ma said that, unlike many ferns, this one likes the sun.
It potentially could be cultivated in water and act as a natural arsenic filter. And
the fern's arsenic-loving genes potentially could be spliced into other plants.
``The fact that it can take something that is toxic at extremely low concentration and
accumulate it at high concentrations is very useful,'' said Stephen Ebbs, a plant
researcher at Southern Illinois University.
Some plants already are used to remove other pollutants from the environment, a process
known as phytoremediation.
But the plants do not concentrate the toxins as strongly as the brake fern.
The report of the fern's special properties comes at a time of intensified worry about
arsenic in drinking water.
Last year, a World Health Organization study said that as many as 77 million of
Bangladesh's people are at risk of poisoning from naturally occurring arsenic in drinking
Two weeks ago, the Environmental Protection Agency announced a much tighter standard
for arsenic in American drinking water, forcing about 3,000 communities to take stronger