Changing the balance of bacteria in drinking water to benefit consumers

(Press-News.org) WASHINGTON, Oct. 25, 2012 — The latest episode in the American Chemical Society's (ACS') award-winning Global Challenges/Chemistry Solutions podcast series reports that scientists have discovered a plausible way to manipulate the populations of mostly beneficial microbes in "purified" drinking water to potentially benefit consumers.

Based on a report by Lutgarde Raskin, Ph.D., in ACS' journal Environmental Science & Technology, the new podcast is available without charge at iTunes and from www.acs.org/globalchallenges.

In the new episode, Raskin explains that municipal water treatment plants typically try to minimize the growth of microbes in the huge filters that remove small particles and substances that can serve as nutrients for bacterial growth. These facilities also add chlorine or other disinfectants to kill bacteria and prevent them from thriving in water distribution pipes.

Nevertheless, it's not possible to totally eliminate bacteria with current technology, making it important to determine how the filter and other water treatment steps impact the types and amounts of bacteria that remain. That's why the researchers set out to do this in a study at a treatment plant in Ann Arbor, Mich.

Their research provides suggestions on how to change which bacteria wind up in the drinking water. The scientists found that certain types of bacteria attach to the filters where they form biofilms. Small clumps of the bacterial biofilm can break off and make it into the drinking water supply. The water's pH was a strong factor in determining which bacteria made it into the drinking water.

Measures as simple as varying the water pH or changing how the filters are cleaned, for example, could help water treatment plant workers shift the balance toward bacteria that are beneficial for humans by not allowing the harmful bacteria to compete.

Global Challenges/Chemistry Solutions is a series of podcasts describing some of the 21st century's most daunting problems, and how cutting-edge research in chemistry matters in the quest for solutions. Global Challenges is the centerpiece in an alliance on sustainability between ACS and the Royal Society of Chemistry. Global Challenges is a sweeping panorama of global challenges that includes dilemmas such as providing a hungry and thirsty world with ample supplies of safe food and clean water, developing alternatives to petroleum to fuel society, preserving the environment and ensuring a sustainable future for our children and improving human health.

For more entertaining, informative science videos and podcasts from the ACS Office of Public Affairs, view Prized Science, Spellbound, Science Elements and Global Challenges/Chemistry Solutions.

### The American Chemical Society is a nonprofit organization chartered by the U.S. Congress. With more than 164,000 members, ACS is the world's largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.

To automatically receive news releases from the American Chemical Society, contact newsroom@acs.org.