Water Talk - Manganese in drinking water
Health Canada has developed two new guideline values (a health-based value and an aesthetic objective) for manganese in drinking water to protect the health of Canadians. Learn about the health effects of manganese and how to reduce your exposure if it is present in your drinking water.
On this page
- Manganese in drinking water
- Health effects of manganese in drinking water
- Guideline value for manganese in drinking water in Canada
- How to reduce your exposure to manganese in drinking water
- Removing manganese from drinking water
- Values in other countries
- For more information
Manganese in drinking water
Manganese is an essential nutrient found naturally in the environment. It can be present in:
- soil and rocks
Manganese gets into drinking water sources when water dissolves minerals that contain manganese. It can also enter drinking water sources through human activity, such as:
- mining activities
- industrial discharge
- leaching from landfills
Manganese may also be added during the treatment of drinking water. In Canada, levels of manganese in fresh water are usually low. In groundwater and some lakes and reservoirs, levels of manganese can be higher depending on water chemistry and due to industrial discharges.
The only way to know if you have high levels of manganese in your drinking water is to have your water tested. Manganese may discolour the water. However, that may not always be the case. If you are interested in testing your drinking water for the presence of manganese, particularly if you have a private well, you should contact your municipality or local public health authority for advice and assistance with the testing.
Health effects of manganese in drinking water
Although humans need to consume small amounts of manganese to be healthy, too much manganese in drinking water can lead to some adverse health effects.
Drinking water that contains high levels of manganese, even for a short time, can be a health risk to infants.
Formula-fed infants may be especially at risk if the water used to prepare the formula contains levels above the guideline value. This is because:
- their brains are developing rapidly
- they drink more water based on body weight
- they absorb more manganese and are less able to remove it from their bodies
Exposure to manganese in drinking water can cause:
- neurological and behavioural effects
- deficits in memory, attention and motor skills
For adults and older children, short-term exposure to manganese in drinking water slightly above the guideline is unlikely to cause negative health effects.
Guideline value for manganese in drinking water in Canada
Health Canada worked with provinces, territories and other federal departments to set a new guideline value for manganese in drinking water of 0.12 milligrams per litre (mg/L). The guideline value is protective of the health of Canadians, including the most vulnerable members of society, such as infants and children.
Manganese has long been considered to be an aesthetic concern in drinking water, because it discolours water and can stain laundry or fixtures. As such, Health Canada has established an aesthetic objective of 0.02 mg/L.
The Guidelines for Canadian Drinking Water Quality for Manganese are based on recent scientific studies and set out the basic parameters that every water authority should strive to achieve in order to provide the cleanest, safest and most reliable drinking water possible.
How to reduce your exposure to manganese in drinking water
If you have elevated levels of manganese in your drinking water, there are effective ways to remove it as described below.
Manganese will not enter the body through the skin or by breathing in vapours while showering or bathing. Bathing and showering in water that contains levels of manganese above the guideline value is considered safe.
If you are pregnant, breastfeeding or caring for an infant
If you are pregnant, breastfeeding or preparing infant formula and are concerned about your infant's exposure to high levels of manganese in drinking water you may wish to:
- use an alternate source of drinking water
- install a treatment device to remove manganese from drinking water
Removing manganese from drinking water
There are two categories of treatment units that are capable of reducing manganese in water in your home:
- units installed directly at the tap: used to reduce specific contaminants at one tap only (point of use units). Reverse osmosis is the most effective and reliable way to reduce manganese levels in drinking water that will be used for drinking and food preparation.
- units installed where the water supply enters the home: used to reduce specific contaminants in water in the entire household (point of entry units). Water softeners and manganese "greensand filters" can be used to reduce the potential for discoloured water and staining of laundry. Greensand filters require careful maintenance to ensure that they are effectively removing manganese.
Make sure that any treatment unit you use is:
- certified as meeting the NSF International / American National Standards Institute standard for the drinking water treatment unit or materials
- installed and maintained (or replaced) according to the instructions given by the manufacturer
Currently, there are no reverse osmosis units that are certified specifically for manganese removal. However, a unit that is certified to remove other metals, such as arsenic or lead, will also be effective for manganese removal. Periodic testing should be conducted on both the water entering the treatment unit and the finished water to verify that treatment is effective.
Values in other countries
Health Canada has established a health-based guideline value for manganese in drinking water of 0.12 mg/L and an aesthetic objective of 0.02 mg/L, some of the lowest limits for manganese in drinking water in the world.
Other countries and organizations have established limits for manganese in drinking water that are different from ours for various reasons (for example, a different value is used to determine how much water a person drinks based on the country average).
Health-based guideline value
Health Canada's health-based guideline value for manganese in drinking water (0.12 mg/L) takes into account new science suggesting potential adverse health effects on the central nervous system, particularly during brain development. Other organizations have also established limits for manganese in drinking water:
- United States: health advisory value of 0.3 mg/L
- Australia: guideline value of 0.5 mg/L
- World Health Organization: health-based value of 0.4 mg/L, but no formal guideline was established
Health Canada's aesthetic objective for manganese in drinking water (0.02 mg/L) is based on new science and is lower than those currently established by other agencies:
- United States: 0.05 mg/L, based on aesthetic considerations
- Australia: aesthetic guideline of 0.1 mg/L
- European Union: limit of 0.05 mg/L
For more information
- Guideline for Canadian Drinking Water Quality for Manganese
- If you have questions about the guideline or manganese in drinking water, you can contact us at:
- 1-833-223-1014 (toll free)
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