Nitrate

High levels of nitrates can lead to a rare but serious condition in pēpi called 'blue baby syndrome' (methaemoglobinaemia).

This condition affects infants under 6 months old and unborn pēpi. It happens when bacteria in the gut convert nitrate into nitrite. Nitrite binds to protein in the blood, which blocks oxygen from circulating properly.

Symptoms include:

• a bluish tinge around the mouth, hands and feet
• breathing difficulties in severe cases.

This is a rare condition in Aotearoa New Zealand. But it is still important for whānau to be aware of the risks — especially if you use private or bore water.

There are several ways that people can consume nitrate. Drinking water is one of these. Typical sources of nitrate in the environment include:

• fertilisers
• animal waste, particularly in areas of intensified farming 
• unreticulated sewage disposal systems
• industrial and food processing waste.

Nitrate is highly soluble in water. This allows it to move easily through the soil and leach into groundwater and drinking water sources.

People in high-risk groups should not consume water that is high in nitrate. 

High-risk groups include:

• bottle fed pēpi less than 6 months old
• pēpi given boiled water
• pregnant women.

Adults with specific rare metabolic disorders may also be at risk, such as:

• deficiency of glucose-6-phosphate dehydrogenase
• methaemoglobin reductase.

Exclusively breastfed pēpi are not at risk because nitrate and nitrite do not pass into breast milk.

Making sure your drinking water is safe

Taumata Arowai is the drinking water regulator in Aotearoa New Zealand. They set a maximum acceptable value of nitrate allowed in drinking water. Water suppliers use this to make sure their water is safe.

Maximum amount of nitrate that is acceptable in drinking water — Taumata Arowaiexternal link