"TORONTO - Children whose drinking water contains high concentrations of manganese appear to have lower IQ scores on average than children not exposed to the metallic element, researchers have found.
In a study of more than 350 children in Quebec communities dependent on tap water from wells, researchers found a striking correlation between manganese levels in the water and IQ scores.
"It's pretty straight-up," said lead author Maryse Bouchard, a researcher in environmental health at the University of Montreal.
"We saw that the average IQ decreased with increasing tap water manganese concentration," Bouchard said from Montreal. "And the difference between the least exposed and the most exposed was in the order of six IQ points, which is a very big difference."
The researchers, whose paper is published in Monday's issue of the journal Environmental Health Perspectives, tested tap water used by 251 families living in eight communities in an area roughly between Montreal and Quebec City."