MADISON, Wis. -- A News 3 investigation found that a naturally occurring metal called manganese has invaded the Madison Water Utility, prompting some complicated health concerns.

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Manganese at high levels can cause neurological problems. More than two years after manganese was first found in the city's water supply, the city officials still don't know exactly who's at risk, WISC-TV reported.

"There are peer-reviewed journals out there that indicate manganese at high enough levels can be toxic, particularly to kids less than six months of age, or people with liver issues," said John Standrdige, commissioner of the Water Utility Board.

"From what we know at this point, it's really not in a range that would cause a normal person any problem," said Dr. Thomas Schlenker, joint director if the Madison-Dane County Health Department.

But a News 3 investigation found that no one really knows the extent of the manganese risk, and probably won't for at least another year.

That's partly because you can't just measure manganese at the wells. The black sediment can also build up inside city pipes, then slough off and come out in your home tap.

The past few months, the Water Utility has been testing homes on a voluntary basis in two areas served by wells with high manganese.

"Even though I don't know much about the manganese problem, I want to be part of having my water tested -- especially if it'll give me some insight into what's coming out of my faucet," said Carol Weidel, a homeowner who is having her water tested.

While the testing helps individuals, public officials told News 3 it doesn't reveal the total risk because the sampling isn't random enough.

Officials want to correct that with a new manganese study. They said they may scientifically sample possibly 10,000 homes starting this summer.

Manganese in drinking water is not regulated, but the EPA recommends .50 parts per billon to avoid discoloration and staining and 300 parts per billion to avoid health risks.

So far, News 3 reported that three wells test over the color/odor limit. A well on the near eastside has the highest manganese content more than 200 parts per billion.

Some home samples were even higher, News 3 reported.

Utility officials are still downplaying the risk.

"We're relying on the fact that these are isolated instances and there not long-term consistent levels that people are seeing at their taps," said David Denig-Chakroff, a manager at Madison Water Utility.

Experts say as long as you avoid water that is discolored, you should be fine.

That's usually the case, but News 3 found one unsafe home sample that came from clear water. It's just one more mystery with manganese, an essential nutrient that at some unknown point becomes toxic.

Waupaca resident Bernadette Mayek, 69, was diagnosed six months ago with the muscle robbing disease ALS, or Lou Gehrig's disease. She had twice the normal level of manganese in her blood.

Her daughters said she also remembers that her well water, at times, looked black or brown.

Her doctor, Benjamin Brooks of the UW Neurology ALS Clinic, said that it's possible her disease is linked to manganese.

"Clearly, it is definitely possible in terms of medical studies that in some communities where there's a high manganese, there have been related increased prevalence to amyotrophic lateral sclerosis type diseases," said Brooks.

How Mayek got ALS is far from clear.

But News 3 found that neurotoxicity concerns over manganese in drinking water is a hot research. One newer study even asserts you might get manganese poisoning from your shower.

Some North Carolina doctors used animal studies to conclude 9 million Americans might be at risk of permanent brain damage by breathing vaporized manganese at drinking water levels deemed safe.

Doctors say it all shows the need for more research.

"We are at a point where this has become such more of a public concern," said Brooks.

Related Links:

Wisconsin Department Of Natural Resources' "Celebrate National Drinking Water Week" Page
Madison Water Utility
Madison Department Of Public Health