Taking regular showers could pose a health risk and even result in permanent brain damage, it was claimed today.
Scientists believe that breathing in small amounts of manganese dissolved in the water may harm the nervous system.
The damage may occur even at levels of the naturally occurring metal normally considered safe, say the US researchers.
Although manganese levels in public water supplies are monitored, regulators have not considered the long-term effects of inhaling vaporised manganese while showering, they claim.
"If our results are confirmed, they could have profound implications for the nation and the world," said Dr John Spangler, from Wake Forest University School of Medicine in Winston-Salem, New Carolina.
"Nearly nine million people in the United States are exposed to manganese levels that our study shows may cause toxic effects.
"Inhaling manganese, rather than eating or drinking it, is far more efficient at delivering manganese to the brain. The nerve cells involved in smell are a direct pathway for toxins to enter the brain. Once inside these small nerves, manganese can travel throughout the brain."
Spangler's team calculated from animal studies the amount of manganese people would absorb by showering for 10 minutes a day.
After 10 years of showering in manganese-contaminated water, children would be exposed to levels of the metal three times higher than the doses needed to leave deposits in rats' brains, the researchers found.
Adults with a longer history of showering could be exposed to doses 50 per cent higher.
More...... http://www.smh.com.au/news/world/regular-s...0329314733.html
Scientists believe that breathing in small amounts of manganese dissolved in the water may harm the nervous system.
The damage may occur even at levels of the naturally occurring metal normally considered safe, say the US researchers.
Although manganese levels in public water supplies are monitored, regulators have not considered the long-term effects of inhaling vaporised manganese while showering, they claim.
"If our results are confirmed, they could have profound implications for the nation and the world," said Dr John Spangler, from Wake Forest University School of Medicine in Winston-Salem, New Carolina.
"Nearly nine million people in the United States are exposed to manganese levels that our study shows may cause toxic effects.
"Inhaling manganese, rather than eating or drinking it, is far more efficient at delivering manganese to the brain. The nerve cells involved in smell are a direct pathway for toxins to enter the brain. Once inside these small nerves, manganese can travel throughout the brain."
Spangler's team calculated from animal studies the amount of manganese people would absorb by showering for 10 minutes a day.
After 10 years of showering in manganese-contaminated water, children would be exposed to levels of the metal three times higher than the doses needed to leave deposits in rats' brains, the researchers found.
Adults with a longer history of showering could be exposed to doses 50 per cent higher.
More...... http://www.smh.com.au/news/world/regular-s...0329314733.html
