Nitrogen and Water

Nitrogen in water

Nutrients, such as nitrogen, phosphorus and potassium, are essential for plant growth and modern agriculture but the overabundance of  nitrogen nutrients in water can cause a number of adverse health and ecological effects. Nitrogen is a plant nutrient when in the forms of nitrate, nitrite, or ammonium, is a nutrient needed for plant growth. 


Nitrate is used in modern agriculture to grow crops, and on many farms the landscape has been greatly modified to maximize farming output/yield. Fields have been leveled and modified to efficiently drain off excess water that may fall as precipitation or from irrigation practices.


The concern is that nutrients added in modern farming enters the water system.


What is the regulatory standard for nitrate?

The United Kingdom and European standard for the concentration of nitrate in drinking water is 50 parts per million (50 mg/l).

Eutrophication – Is the process by which a body of water acquires a high concentration of nutrients, especially phosphates and nitrates. These  promote excessive growth of algae. As the algae die and decompose the levels of organic matter and the decomposing organisms deplete the water of available/dissolved oxygen, causing the death of other organisms, such as fish.

Anoxia – is a lack of dissolve oxygen caused by excessive nutrients in waterways which triggers algae growth. When the plants die and decay, oxygen is stripped from the water, which then turns green or milky white and gives off a strong rotten egg odour.  The lack of oxygen is often deadly for invertebrates, fish and shellfish.