Nova Scotia's chief medical officer of health is urging people who rely on well water to ensure it is tested every six months for bacteria and every two years for chemical contaminants including manganese.

Dr. Robert Strang said prolonged exposure to the element can interfere with children's brain development and affect adults' memory, attention and movement.

On May 10, Health Canada issued new guidelines for manganese in drinking water: no more than 0.12 milligrams per litre. It said infants are most sensitive.

Elizabeth Kennedy, the director of water and wastewater for the provincial Department of Environment, said the limit used to be easily be detected due to discolouration, but the updated guidelines focus on protecting people's health in the long term.

"At that level you couldn't taste or smell it, so you'd actually have to test to know whether or not the manganese is in the water," she said.

Though high concentrations of manganese can discolour water, it can still have negative long-term health effects in smaller quantities. (Curtis Rumbolt/CBC)

Kennedy said the mineral is found in soil throughout Nova Scotia and levels vary across the province.

"It makes its way into the groundwater and surface water as the water flows through the rocks and soil, it picks it up and it can make its way into our drinking water supply that way," she said.

People consume manganese through their food as it occurs naturally in the environment, but it can also end up in water sources as discharge from mining or leaching from a landfill. Health Canada said it's used in steel production and some types of manufacturing.

Majority of people on private wells aren't testing water

The Nova Scotia government said since more than 40 per cent of residents have well water at their homes, people need to ensure it is safe. But Kennedy said the majority of those residents on private wells still don't have their water tested regularly.

People are advised to follow instructions for dropping off samples and ensure their water is screened for more than 25 contaminants, including arsenic, lead and uranium. The process costs $200 to $300.

The province said testing for bacteria costs $30 to $50.

"If you do your test, and you find that you have parameters that are higher than what Health Canada recommends for drinking water, then you should look into installing a water treatment system for your house, ideally, and if you can't do that then find an alternative water supply," said Kennedy.

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