Why are nitrates in water

 What is nitrate, what is nitrite?

Nitrate and nitrite are nutrients that have been used for many years as fertilizers (nutrients) in agriculture, but also in municipal areas (allotments, etc.). Nitrate and nitrite are mutually convertible depending on the oxygen content in the water; further nitrogen compounds are ammonium or elemental nitrogen (see also the scientific basics). A typical property of nitrate is its good solubility in water, i. That is, if too much nitrate is used, it is quickly washed out of the soil and thus ends up in the green water or in drinking water.

What health relevance does nitrate have for me?

Nitrate (limit value according to the Drinking Water Ordinance: 50 mg NO3 / l) in concentrations> approx. 100 mg NO3 / l causes considerable health problems in babies up to 6 months of age. Nitrate, which can also be converted to nitrite in the human body, causes the blood to bind these nitrogen molecules better instead of oxygen, which ultimately leads to "blue addiction" (methaemoglobinemia) (suffocation) in infants. For older children and adults there is a risk of the formation of nitrosamines only at higher concentrations, which can again be carcinogenic. There is also the risk of developing goiter.

How can I find out the nitrate content of the water?

There are small ready-made tests to determine the nitrate content. Analyzes by a certified water laboratory are more precise and accepted in court. If you are connected to a public supply network, you can find out the nitrate content of the drinking water from your local supplier. The health department also provides information.

What can I do if the nitrate content is too high?

Boiling or filtration through activated charcoal does not counteract excessively high nitrate concentrations! The removal of nitrate from the water is relatively complex. Point-of-use systems reduce the nitrate content through filtration through reverse osmosis, distillation, or disposable deionizers. Another possibility, similar to water softening systems, is an anionic exchange resin instead of the cationic exchange resin that is commonly used for water softening. These systems work in a similar way to conventional water softeners and can be operated in combination with water softeners.

If larger quantities of nitrate-polluted water have to be treated (e.g. public utilities), the above-mentioned Procedures lead to considerable additional costs. Effective methods of nitrate elimination in large waterworks are currently not available (experience is available from waterworks that work primarily on the basis of denitrification. Therefore, attempts are usually made to access other resources or to mix the water with less polluted water.