Simple sticks contain potential answer to cleaner drinking water

Mike Krumboltz
Yahoo News

 A lack of clean drinking water is a major problem in many parts of the world. A scientist from the Massachusetts Institute of Technology thinks he may have come up with a low-cost solution: sticks.

Yes, sticks. Rohit Karnik recently co-authored a study published in the journal PLOS ONE that details how xylem can be used to filter bacteria from water, NPR reports. Xylem, for those whose grasp of botany is tenuous, is a kind of "vascular tissue" in trees and plants "primarily involved in transporting water and nutrients."

Karnik told NPR xylem has "membranes with pores and other mechanisms by which bubbles are prevented from easily spreading and flowing in the xylem tissue." Those pores, Karnik found, could also be used in the filtering of bacteria in water.

From NPR:

To prove it worked, he created a simple setup in his lab. He peeled the bark off a pine branch and took the sapwood underneath containing the xylem into a tube. He then sent a stream of water containing tiny particles through the tube and showed that the wood filter removed them.

You can watch a video of the experiment here.

Karnik found that the membranes filtered out as much as 99.9 percent of the harmful bacteria.  Not bad, but while 99.9 percent is certainly better than nothing, it still falls well short of catching everything. And what it doesn't catch could still prove dangerous.

NPR spoke with Stanford University environmental expert Robert Jackson who said that when it comes to filtering bacteria, "you don't want to rely on something that's 99 percent effective."

Still, Karnik's conclusion, if accurate, is a sign he and his team are on the right track. He writes that "further research and development of xylem filters could potentially lead to their widespread use and greatly reduce the incidence of waterborne infectious disease in the world."

Approximately 3.4 million people die each year from a water-related disease, according to, and 780 million don't have access to clean drinking water.

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