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Public Radio's Environmental News Magazine (follow us on Google News)

Emerging Science Note/Cleaning Contaminants

Air Date: Week of

What do algae, ultrasonic waves, and mercury contamination have in common? Emily Taylor reports on a possible savior for polluted rivers.


TAYLOR: Goodbye, heavy metal. Hello, soft rock.

Scientists at Ohio State University have come up with a new combination of technologies that they hope will someday be used to clean heavy metals out of riverbeds contaminated by pollution.

By using ultrasonic waves, researchers Ziqi He and Linda Weavers were able to shake mercury loose from sediment particles resting in water in their lab. But they quickly found themselves with a new problem. Because the mercury had been vibrated loose, it was now contaminating the water. So, Weavers and He turned to their colleague Richard Sayre, a professor of plant, cellular and molecular biology.

Sayre and his team had genetically modified a species of algae designed to absorb certain heavy metals. Then the two teams put their two technologies to the test. They used an ultrasonic probe in a beaker filled with water, contaminated sediment, and algae. As predicted, the mercury was vibrated free, and within seconds the algae had absorbed up to 60 percent of the mercury from the water. After the first few minutes, 30 percent of the mercury in the sediment was gone.

Although other technologies exist to remove metals from sediment, this system is more efficient because the algae has been modified to absorb a single metal group, rather than all metals, making it five times more absorptive. The researchers hope to put the technology to use in contaminated river beds where sediment could be removed, cleaned, then replaced without greatly harming wildlife.

That’s this week’s Note on Emerging Science, I’m Emily Taylor.



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