While the household tap water filters that Flint, Michigan residents have been given are effective at removing lead from drinking water, researchers say they may unwittingly encourage the growth of microbes, including some that could cause diseases in people with weakened immune systems.
“We study how changes in the water quality affect the types of microorganisms that grow in the filter. What we found is that even very small minute changes in some trace compounds to begin with can have a dramatic affect on the types of microorganisms that grow (on the filter),” said Terese Olson, associate professor of civil and environmental engineering. ‘We’re concerned about the Flint system because this water has certainly undergone some dramatic changes and the types of microorganisms we might expect would be different.
The filters, Olson says, are “designed to treat polished drinking water. They’re not designed to handle water that has high particle or high bacteria content.”
In a somewhat related issue, Lut Raskin, professor of civil and environmental engineering, weighs in on what may have caused the outbreak of Legionnaires’ Disease. She blames many confounding factors, including excess iron in the water from corroding pipes, higher summer temperatures and higher levels of nutrients in the water, all of which could have encouraged the growth of Legionella.
For these and other reasons, the professors are calling for ongoing monitoring of Flint drinking water quality, regardless of the source.