Manganese levels in Winnipeg water have been steadily increasing over the past few years, according to city tests.
And the highest level recorded in recent routine testing of Winnipeg's water is raising health concerns, according to Maryse Bouchard, a professor at the University of Montreal who studies the toxicity of environmental contaminants.
The highest concentration of manganese was 0.10 ppm, or parts per million in testing results from January to June 2013. Bouchard said that raises red flags.
"That concentration might be associated with modest cognitive deficits in children," she said. She adds it would also need to be ingested consistently over several months.
That level is also double the national esthetic guideline for drinking water, which is 0.05 ppm. The guideline refers only to the taste, colour and smell of water. There is no health and safety guideline for manganese in Canada. Bouchard thinks there should be, though.
"I strongly believe there should be a health-based guideline indeed, and I know some people at Health Canada are sensitive to the subject," she said.
Bouchard authored a study in 2010 that showed elevated manganese in drinking water is associated with lower IQ in children. Health Canada is sponsoring her current research into manganese in New Brunswick water.
When Winnipegger Kari McFarlane heard about the city's recent water test results, she was disappointed.
"It's just going to make people buy more bottled water or filters," she said. But it reinforced her decision give her son bottled water to drink even though it costs more.
"I think it's silly to spend a lot of money on bottled water... because it is free, but if it's gross and undrinkable, then people are going to waste a lot of money," she said.
But it is not just the maximum level of manganese that is increasing. A city report said the average is going up, too.
The average level of manganese detected in drinking water at six distribution points throughout the city showed a jump from 0.006 ppm in 2009, to 0.04 ppm for the first half of 2013.
Diane Sacher, director of Water and Waste for the City of Winnipeg, said the city is working to get the levels down.
"In addition to the water being safe, we do want it to be esthetically pleasing as well," she said. "So it's a concern for us and that's why we're trying to solve this problem." Sacher insists the water is safe and said the city has been trying to solve the problem for years.