Nitrate
What are nitrates?
Nitrates are naturally occurring forms of nitrogen found in the environment. Nitrate is:
- essential for plant growth
- present in all vegetables and grains
- commonly used in fertilizer
What are the health effects of nitrates?
Infants are at highest risk for elevated nitrate levels. The primary health concern associated with nitrate exposure is methaemoglobinaemia, or blue-baby syndrome. The nitrate enters the bloodstream where it interferes with the blood’s ability to carry oxygen.
The symptoms of methaemoglobinaemia include:
- cyanosis (bluish discoloration of the skin and mouth)
- shortness of breath
- fatigue
Most cases occur in infants under 1 year of age. Infants less than 3 months of age are particularly susceptible. If your child is experiencing these symptoms see your health care provider.
How are nitrates tested in water?
Municipal water is tested for nitrates and treated if the results are above the Ontario Drinking Water Quality Standards of 10 mg/L. Private drinking water systems should be tested for nitrates especially if infants or expectant mothers are using the water. Nitrate testing needs to be done through an accredited private lab.
Common sources of nitrate in well water are:
- chemical fertilizers used to improve plant growth
- manure from barns, storage areas, and applied to land
- waste from septic fields, leaking septic tanks, or holding tanks
- soil that contains nitrogen compounds from naturally decaying organic matter
What should you do if you have high nitrate levels?
- Find another safe source of drinking water.
- Infant formula should be used after making an informed decision. A safe source of drinking water should always be used when making formula. Water high in nitrate should not be used to prepare infant formula and should not be given to infants to drink.
- Nursing mothers and pregnant women should also avoid drinking water high in nitrate as it may be present in breast milk or transported through the placenta.
- Nitrate does not pose a risk when the water is used for washing or bathing.
- If possible remove sources of nitrate in the area.
- Inspect your well to ensure contamination cannot enter.
- Consider water treatment. Consult a water treatment specialist regarding point of use or whole home treatment systems for nitrates.
- Consider replacing your well. Elevated nitrate levels are more common in shallow, dug wells than in deeper, drilled wells.
This item was last modified on April 19, 2024