Manganese in Drinking Water
Manganese is a naturally occurring element that is common in PEI rocks and soils. Under oxygen-rich conditions, manganese is relatively insoluble and its concentration in groundwater is generally quite low. In cases where oxygen levels in groundwater are low, such as in swampy areas, manganese is much more easily dissolved and can be present in water at significantly higher levels.
What are the health concerns?
Manganese is considered to be an essential element for humans and at the concentrations generally found in groundwater, it is not considered to be a threat to health. Elevated manganese levels can be of concern for aesthetic reasons because of unpleasant tastes, staining of laundry or fixtures and encrustation of water pipes. To minimize these problems, the Guidelines for Canadian Drinking Water Quality include an aesthetic objective for manganese of 0.05 mg/L.
What are the treatment options?
Elevated manganese levels can be reduced by the use of a water treatment device. It is recommended that advice from a qualified groundwater professional be sought prior to deciding what solution best meets your particular situation. Because the undesirable aesthetic impacts of high manganese concentrations can affect a variety of domestic water uses, it is generally best to treat water at the point of entry to the house. The most common water treatment devices for reducing manganese are Greensand filters. When manganese levels are only slightly elevated, a water softener may also be effective in reducing manganese concentrations in water.
The Department does not recommend specific brands of treatment devices; however, it is recommended that purchase devises bearing a label that indicates it has been certified to NSF/ANSI Standard 44 for Cation Exchange Water Softeners or NSF/ANSI Standard 61(for drinking water system components – health effects).
As with the use of any drinking water treatment device, the effectiveness of treatment should be verified by sampling after installation. In addition, it is important to ensure the device is used and maintained according the manufacturer’s directions and its performance periodically confirmed by sampling.