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Professor finds link in cancer, chemical
Manganese seems to play good and bad roles
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Published: August 2, 2009
The amount of manganese in the environment could be a factor in local and state cancer rates.
A recent study by a Wake Forest University School of Medicine researcher has found that, like cholesterol, there may be a good kind -- airborne -- and a bad kind -- groundwater -- of exposure to the chemical element.
Manganese is considered essential for good health in trace amounts but toxic at higher exposures.
According to the Environmental Protection Agency, existing scientific information cannot determine whether excess manganese can cause cancer.
Humans get manganese primarily through food such as grains and rice, soybeans, eggs, nuts, olive oil, green beans, oysters, spinach, tea, pineapple and herbs.
However, manganese is replacing lead in gasoline globally as an anti-knock octane booster, said Dr. John Spangler, a professor of family and community medicine at the medical school.
"Manganese levels around the world will be increasing over the coming years," Spangler said. "Some of the manganese will get into the air, and some into the water supply."
J.C. Reid, a researcher for the N.C. Geological Society, was a co-author of the study, which also used data from 1997 to 2001 from the N.C. State Center for Health Statistics, the U.S. Geological Society and the U.S. Census. The study was published online by Biological Trace Element Research.
What the WFU study found is that levels of groundwater manganese and airborne manganese correlate with cancer mortality at the county level in North Carolina.
For example, groundwater manganese was associated with a 28 percent increase in colon-cancer deaths and a 26 percent increase in lung-cancer deaths related to elevation of manganese in groundwater as opposed to air.
By comparison, airborne manganese was associated with a 14 percent decrease in total cancer deaths, a 43 percent decrease in breast-cancer deaths and a 22 percent decline in lung-cancer deaths.
"That's pretty astounding," Spangler said. "These are the first data we know of to document a potential relationship between environmental manganese and population-level cancer death rates."
The study found that Forsyth County had the 19th-highest exposure to manganese in groundwater among the state's 100 counties, along with the 11th-highest exposure to airborne manganese.
"We are high on groundwater manganese, which might be associated with cancer," Spangler said. "But also high on air levels, which might be related to reducing cancer.
"How those two interact is beyond the scope of what could be accomplished with our data set."
The study found that several counties in the Triad and Northwest North Carolina had a high level of exposure to airborne manganese. Davidson County had the highest exposure in the state, with Randolph County third, Wilkes fourth, Watauga fifth, Guilford eighth and Davie 13th.
When it comes to the groundwater manganese exposure, Forsyth was the highest in the region, and Alleghany, Watauga and Ashe counties had the lowest exposure in the state.
Whole Foods, on its Web site, touts manganese as helping the body with keeping bones strong, synthesizing fatty acids and cholesterol, maintaining normal blood-sugar levels and healthy nerves, and promoting optimal function of the thyroid gland.
The company also said that foods high in manganese can help with nausea, vomiting, poor glucose tolerance, skin rash, loss of hair color, excessive bone loss, low cholesterol levels, dizziness, hearing loss and reproductive-system difficulties.
According to the Web site www.lenntech.com, manganese primarily affects the body in the respiratory tract and the brain.
Symptoms of manganese poisoning are hallucinations, forgetfulness and nerve damage. Too much exposure to manganese also can cause Parkinson's disease, lung embolism and bronchitis.
Spangler said that the impetus for his research came from being asked to be involved in litigation in Raleigh in which a large community/neighborhood was supplied with water from four private wells operated by the community's developer.
"The water had high levels of manganese," Spangler said. "Some children, in my opinion, were harmed. This piqued my interest in manganese as an environmental toxin.
"This is not a perfect way to detect an association, and it does not prove causation. On the other hand, this type of study can detect associations that are best seen at the population level."
■ Richard Craver can be reached at 727-7376 or at
rcraver@wsjournal.com.
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