Air Date: Week of March 23, 2012

Scanning Electron Microscope image of lead surface covered with pyromorphite by the fungus Paecilomyces javanicus. (Photo: Young Joon Rhee, via Current Biology)

Researchers have found that adding fungus to lead-contaminated soil could be an efficient way to clean up polluted areas. Living on Earth’s Mary Bates reports on the power of fungus.

Transcript

GELLERMAN: Coming up, an ode to sandhill cranes in New Mexico. But first, this Note on Emerging Science from Mary Bates.

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BATES: Lead pollution is a serious problem around the world. Now scientists believe having a fungus among us may cut down on lead contamination. Soil gets contaminated with lead from many sources, including industrial waste and lead from firearms. One way to neutralize lead in contaminated soils is to add phosphorous, an element that interacts with lead to form a stable and nontoxic mineral called pyromorphite. But this makes the soil more acidic, which can cause leaching of toxic heavy metals. And sometimes the process isn’t very efficient.

Researchers from the University of Dundee in Scotland may have a better solution. They found some types of fungus can transform lead into its most stable mineral form. What’s more, they say this interaction between fungi and lead may be occurring naturally anywhere the two are found together.

Researchers tested how lead shot broke down with and without help from fungi. When fungi were added, they saw the formation of pyromorphite within one month. And the amount of lead converted to pyromorphite kept increasing over time. Without fungi, the lead shot corroded into less stable, and more toxic, forms.

This is the first report of fungi transforming metallic lead into pyromorphite. It’s also the first demonstration that the change from lead to pyromorphite can result from a biological process rather than a purely chemical and physical one.

The discovery that some fungi can transform toxic lead into a nontoxic mineral points to a new method of bioremediation. Introducing fungi to lead polluted sites could be a safe and efficient way to get the lead out. That’s this week’s note on emerging science, I’m Mary Bates.

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Links

Abstract in Current Biology