Study: More than one way to treat water

Published May 9, 2006.

ROLLA, Mo., May 9 (UPI) -- A University of Missouri-Rolla scientist says he's discovered that the use of monochloramine to disinfect drinking water can cause harmful levels of lead.

Chemistry Professor Jay Switzer studied what happens when municipal water districts switch from using chlorine to disinfect drinking water to using monochloramine.

That's what occurred during early 2004 in Washington. Subsequently, officials discovered extraordinarily high levels of lead in homes across the city.

"You have to disinfect drinking water to kill pathogens or to inactivate them and what has traditionally been used is chlorine," said Switzer. "In the field they call this free chlorine. Basically they just bubble chlorine through the water and the practice has been very effective."

But, says Switzer, chlorine reacts with natural organic matter in the water and produces what are called disinfection byproducts. And some of those byproducts, such as trihalomethanes, are suspected to be carcinogenic.

In an effort to reduce carcinogens in drinking water, the EPA began exploring other options and, while not quite as effective as chlorine, monochloramine doesn't produce any trihalomethanes.

Switzer details his research in the May 15, 2006 issue of the journal Environmental Science and Technology.

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