Issue date: 1/31/08 Section: News

Sophomore Sarah Jahnke washes dishes in the Missouri Hall third floor crossover Wednesday morning. Even though Kirksville's tap water might occasionally have a strong smell, the water is not harmful to drink.

Five in a trillion.

That's the concentration of geosmin, a microbe-produced organic compound that some people can detect. And it's the party responsible for the half-dozen complaints Kirksville Public Works has received this year about taste and odor problems with tap water.

Public Works Director John Buckwalter said some individuals can sense the presence of geosmin long before others.

"Some people can detect it at a level of five parts per trillion," Buckwalter said. "It's a question of sensitivity. We've visited homes where someone had called and the husband couldn't smell or taste it and the wife could."

Twice a year, in early January and late August, a blue-green algae that emits geosmin during metabolization and death is particularly active, Buckwalter said. The geosmin presence this year is far less extensive than last year around the same time.

He said Public Works hasn't gotten any calls for at least the past 10 days. Once geosmin has dissolved in the water, it cannot be filtered out - though if problems are widespread, that batch of water can be flushed through the system, Buckwalter said. It takes between two and three days for water to flow from the treatment plant to city residences, and as long as six days before it has gone through the rural water district.

Buckwalter emphasized that geosmin, which produces an earthy smell partly responsible for the taste of beets and catfish, is not harmful.

"The water is safe," he said. "The taste and odor is aesthetic, but it makes people think the water is not safe."

The water that pours from Kirksville residents' faucets comes from Forest Lake and Hazel Creek Lake, the city's two surface water reservoirs.

Last week, Public Works switched the current water supply from the Forest Lake reservoir to the Hazel Creek Lake reservoir. Buckwalter said the city alternates between the lakes about once or twice a year.

"It happened to be at the same time we had some taste and odor complaints, but that was not why we switched," he said.

Continued...

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