A new Canadian study has found that children who drink water contains high concentrations of manganese appear to have lower IQ scores on average than children not exposed to the metallic element.
Does this concern those of us "south of the border?" You bet it does — for two reasons: Because there are no enforceable federal drinking water standards for manganese here in the United States, and because these effects occurred at exposures even below the recommended maximum level of manganese (300 mcg/l) set by the U.S. Environmental Protection Agency.
The Canadian study followed more than 350 children in Quebec communities, examining their exposure to manganese via tap water from wells. The researchers tested tap water used by 251 families living in eight communities in an area roughly between Montreal and Quebec City.
Neuropsychologists gave a series of tests to the children to determine their general cognitive abilities, including verbal, visual-spacial and concept-formation skills. They found the difference between the least exposed to manganese and the most exposed was in the order of six IQ points, a significant difference.
The area in the study had no industrial source of manganese. In other words, there were no battery factories, steel plants or industrial plant fertilizers used nearby. Manganese is a natural element commonly found in groundwater due to leaching from minerals and rocks. The element is not usually noticed in tap water until it reaches a level of around 500 mg/l, at which point it imparts a slightly different color, odor, and taste to the water.
It is not regulated for health effects, because most major health effects are not a concern until concentrations are about 10 times higher. At that point, exposure to high concentrations of manganese over the course of years has been associated with toxicity to the nervous system, producing a syndrome that resembles Parkinson's disease.
But this study shows that even low levels of manganese may be a concern for young children. While a small proportion of children involved in the Canadian study had drinking water with manganese concentrations above recommended guidelines, according to researchers who said "96 percent of our children were exposed to levels that are supposed to be safe."
Think you might have high concentrations of manganese in your drinking water? Have your water tested by a state-certified laboratory for manganese. A simple water filter may help to correct the problem and protect your kids' noggins!