Arsenic in drinking water is a worldwide problem. Now a discovery by scientists at the University of Oregon could lead to a new way to remove the toxic chemical, making groundwater supplies safer for communities.
In the environment, arsenic is continuously cycling through different forms and combinations. Sometimes it’s dissolved in water, embedded in rocks, or in gas form in the air. Sometimes the chemical has organic molecules attached to it. Sometimes it doesn’t.
The level of threat arsenic poses to humans depends on where it is and what form it takes. And these forms can change as the element interacts with other things in the environment – including living organisms.
That’s basically the process happening in groundwater, first identified by University of Oregon geology professor Qusheng Jin.
Jin and his team tested wells in the small Oregon community of Creswell after hearing complaints from local residents about high arsenic levels in their groundwater.
“In groundwater, most people assume this process is not significant or does not exist,” he said.
Jin found microbes have been naturally transforming toxic water-born arsenic into a gas that can rise and get trapped in the soil, where it’s less of a problem.
The discovery is significant because it could lead to a cost-effective way to lower arsenic levels in drinking water. One approach he said, might be to expose the microbes to ethanol, which would speed up the of transforming arsenic into a gas.
“This potential technology calls for the stimulation of microbes that live in the aquifer. We already showed that by stimulating them, by providing food for them, they will speed up the… process 10 times," Jin said. "As a result, they will convert this organic arsenic to a gas form and the gas form will diffuse away,”
Jin’s research is published in the journal Nature Geoscience.
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University of Oregon Geologist Qusheng Jin
Map of arsenic test area in the Willamette Valley.
