What arsenic did for playwright Joseph Kesselring's "old lace" it's done for countless ranchers, orange growers, and golf-course managers: It's gotten rid of pests.
Used against everything from ticks on cattle and fungus on orange trees to weed killers, arsenic also figures into many industrial processes. Yet its use has left tens of thousands of sites worldwide badly contaminated.
In today's edition of the journal Nature, scientists in Florida report finding what may be a new ally in the battle against arsenic contamination - a lowly fern that, at least until now, state officials had branded an invasive pest.
The plant, commonly called brake fern, displays an appetite for arsenic that surprised its discoverers. Concentrations ranged up to hundreds of times higher in the plant than in the surrounding soil. Unlike many plants scientists have found thriving in metal-tainted soils, the brake fern uses its entire structure to sequester arsenic, not just its roots.
"This fern is really amazing," says Lena Ma, an associate professor in the Institute of Food and Agricultural Sciences at the University of Florida in Gainesville who led the research team that found the plant.
University of Northern Arizona biochemist David Salt agrees.
"The fern is exciting," he says, adding that even if other traits render the plant inadequate to clean up contaminated sites on its own, finding the genetic key to its ability to store arsenic could help researchers engineer more-suitable plants to clean tainted sites.
Dr. Ma notes that the fern, native to China but found worldwide, was one of a number of plants her team collected from an abandoned wood-preservation site in north-central Florida. The scientists were testing the plants to see which ones might prove useful for arsenic cleanup duty. She adds that dealing with arsenic-laced sites is a top priority for Florida environmental officials. The state has some 3,200 arsenic hot spots, she says.