Nearly 9 million people in the United States are exposed to manganese levels that may cause toxic effects. And while small levels of this naturally occurring metal can be found in food and many types of rocks and enters the air, soil and water, high levels of manganese are mainly found in wells and private water supplies.

Iif your water supply has high levels of manganese, the water company is free to say that it is completely safe — even when it could, in fact, be the exact opposite.

With that said, according to an analysis based on animal studies, showering in manganese-contaminated water for a decade or more could permanently affect one's nervous system as well as induce learning and coordination disabilities, behavioral changes and a condition similar to Parkinson's disease. Worse, the damage could occur in levels considered safe by the Environmental Protection Agency (EPA)--an upper limit of 0.5 milligrams/liter.

This research is the first to find the potential for permanent brain damage from inhaling vaporized manganese while taking a shower.

Animal Studies

Researchers reviewed a number of animal studies to determine how much manganese patients absorb by showering 10 minutes a day for a decade. The results correlated that:

• Children would be exposed to doses of manganese three times higher than doses resulting in manganese deposits in the brains of rats.

• Adults would be exposed to doses 50 percent higher than rodents.

Breathing in manganese, rather than eating or drinking it, is much more efficient at transporting manganese to the brain. That's because the nerve cells involved in smell are a direct pathway for toxins to the brain; once inside these small nerves, manganese has the ability to roam throughout the brain.

And a major problem with manganese exposure in the shower: The EPA based its 0.5 milligrams/liter limit on odor and taste, but not the amount one can accumulate in their brain by showering. Thus, regulatory agencies may want to rethink existing drinking water standards for manganese ... and soon.

Medical Hypothesis May 23, 2005

Science Blog June 30, 2005