What is nitrate/nitrite?
Nitrate and nitrite are forms of nitrogen that are in soil and water. Nitrate/nitrite can collect in well water. When levels of nitrate/nitrite are high, it can make people sick.
You can’t taste or smell nitrate and nitrite.
Where is nitrate/nitrite found?
The most common sources of nitrate/nitrite include:
- human sewage from septic systems (on-site waste treatment systems) not working right
- livestock manure
- natural minerals found in the underground area where your groundwater comes from (aquifer)
How does nitrate/nitrite get into my drinking water?
Nitrate and nitrite dissolve in water. If the aquifer that supplies your well has lots of these molecules, the water will carry them to your drinking water tap. How much nitrate/nitrite ends up in your water depends on the source that’s contributing the most nitrate/nitrite.
For example, if the natural source for your aquifer is high in nitrate/nitrite, the molecules will naturally collect and there is no way to stop this. But if something on the surface is the main source, like livestock manure, you can think about managing manure differently to stop the nitrate/nitrite from getting into your water.
In some cases, if a well was poorly constructed, contaminated surface water can get into your water. The contaminated water may also have high levels of nitrate/nitrite.
How does nitrate/nitrite affect my health?
Drinking water with high levels of nitrate/nitrite can make you sick. Drinking water includes all water used to drink or prepare drinks (including infant formula) and the water we use for cooking.
Private drinking water sources like wells, dugouts, and springs can sometimes contain unsafe levels of nitrate/nitrite. If a baby drinks water with high nitrate/nitrite levels or if it’s used to make formula, it might cause methemoglobinemia (blue baby syndrome).
What is methemoglobinemia (blue baby syndrome)?
Methemoglobinemia is an illness that babies younger than 3 months old can die from. It can be caused by drinking water with high levels of nitrate/nitrite.
Methemoglobinemia affects how the blood carries oxygen. As it progresses, symptoms get worse and the skin starts to turn blue.
Symptoms of methemoglobinemia include:
- blue skin (cyanosis)
- trouble breathing
- losing consciousness (coma)
Can anyone get methemoglobinemia?
Babies younger than 3 months have the highest risk, but other people can get methemoglobinemia. You might be at risk if you:
How do I know if there is nitrate/nitrite in my drinking water?
Your water can be tested to see how much nitrate/nitrite is in it. Learn more about testing your drinking water in Alberta.
What is the standard for levels of nitrate/nitrite in drinking water?
Labs can report nitrate/nitrite levels as nitrate and nitrite, or as nitrate-nitrogen (Nitrate N) and nitrite-nitrogen (Nitrite N).
According to Health Canada’s
Guidelines for Canadian Drinking Water Quality, drinking water is safe if it has less than:
- 45 mg/L (milligrams/litre) nitrate or 10 mg/L of nitrate-nitrogen (Nitrate N)
- 3 mg/L nitrite or 1 mg/L nitrite-nitrogen (Nitrite N)
Is there any way to lower nitrate/nitrite levels and prevent methemoglobinemia?
If you have your own source of drinking water, like a well, dugout, or spring, it's important to test your water before your baby’s due date. Learn more about
testing your drinking water in Alberta. If you are using the health centre lab, test results can take several weeks so plan to test your water early.
If your water supply has high nitrate/nitrite levels, install a certified water treatment system:
- A point of use reverse osmosis system with NSF/ANSI 58 certification or a distillation treatment device at your drinking water tap.
- Reverse osmosis forces water through a membrane that filters out molecules like nitrate/nitrite. If you have levels of nitrate/nitrite that are a lot higher than the guideline, like 100 mg/L Nitrate N, reverse osmosis systems might not remove enough nitrates/nitrites.
- Distillation boils water, catches the steam, and condenses it to liquid while leaving the nitrate/nitrite out.
- An ion exchange unit for your whole house. Ion exchange uses the electrical charges of different particles to clean water. If you are only concerned about nitrate/nitrite levels, then you may not need a treatment system for your whole house. In these cases, a point of use system may be more appropriate.
It’s important to test and maintain your treatment system to make sure it works well.
local public health inspector to talk about ways to treat your water.
If you don't want to install a treatment system, use another water source for drinking water like:
- water from an approved municipal (city or town) system
- bottled water
- well water that was recently tested for bacteria and chemicals
Boiling water lowers the risk of it being contaminated with bacteria, but it does
not remove nitrate/nitrite. Boiling will
increase the nitrate/nitrite level in your water.
If my water has high nitrate/nitrite levels, do I need to test for anything else?
Yes. If you have high levels of nitrate/nitrite in your water, you need to test it for bacteria. Learn more about
testing your drinking water in Alberta.
It’s recommended to test private well water for bacteria 2 times a year. The best time to do this is in the spring (after snow has melted), after a very long dry spell, or after a very heavy rain. It’s also a good idea to test for bacteria any time your water tastes, smells, or looks different.
Call your local health centre to find out
how to test your private drinking water supplies for bacteria.