How does nitrate get into groundwater?

Table of Contents

• What is nitrate and what is the limit in drinking water?
• How does nitrate get into the water?
• Effects of nitrate in water on the environment
• Health Risks of Nitrate in Drinking Water
• How to test and reduce nitrate in water?

What is nitrate and what is the limit in drinking water?

Nitrate is a chemical compound found primarily in fertilizers. It is important in water because it is part of the natural nitrogen cycle and supports plant growth. However, too much nitrate in water can be harmful to health, especially for babies and pregnant women. It is important to monitor nitrate levels in drinking water to ensure they remain within safe limits.

Nitrate (NO₃⁻) is a chemical that occurs naturally in soil and is an important component of the nitrogen cycle. It is formed by the oxidation of ammonium and is absorbed by plants as a nutrient. Nitrate also enters groundwater through human activities, such as intensive agriculture (fertilizers) or wastewater.

Health effects: Nitrate itself is not directly harmful in moderate amounts. However, high levels of nitrate in drinking water can cause health problems, especially in infants, as nitrate can be converted to nitrite in the body, which impairs oxygen transport in the blood (methemoglobinemia or "blue baby syndrome").

Environmental aspect: Too much nitrate in the water leads to eutrophication, which means it causes excessive growth of algae and other aquatic plants. This can lead to oxygen deficiency and the death of aquatic life.

That is why there are legal limits for the nitrate content in drinking water.

Nitrate limit value in drinking water: The limit value for nitrate in drinking water in the European Union, including Germany, is 50 milligrams per liter (mg/L). This limit value is set under the EU Drinking Water Directive to protect the health of the population, especially infants, who are particularly sensitive to high nitrate concentrations.

How does nitrate get into the water?

Nitrate enters the water in a variety of ways, mainly through human activities. Here are the main sources:

Agricultural fertilizers: The most common way nitrate gets into groundwater and surface water is through the use of nitrogenous fertilizers in agriculture. When more fertilizer is applied to fields than the plants can absorb, the excess nitrate is washed out into groundwater or enters rivers and lakes through rain.

Livestock farming: Livestock farms produce large amounts of manure, which is used as fertilizer on fields. Here too, excess nitrate can seep into the groundwater.

Wastewater and sewage treatment plants: Nitrate can also enter the water through municipal wastewater, sewage treatment plants or improperly disposed human waste.

Natural decomposition processes: When organic materials, such as dead plants and animals, decompose, nitrogen is released, which is converted into nitrate and can thus enter the water.

Atmospheric deposition: To a small extent, nitrate can also enter the water through precipitation in the form of rain or snow when nitrogen compounds are washed out of the air by car exhaust fumes or industrial emissions.

These sources cause nitrate to enter the groundwater and thus also drinking water wells.

Effects of nitrate in water on the environment

Nitrate in water can have a significant impact on the environment. One of the main problems is the eutrophication of water bodies. This means that algae and aquatic plants grow rapidly due to the high nutrient content. This overproduction can lead to a lack of oxygen, which threatens fish and other aquatic life.

Nitrate can also enter groundwater and affect drinking water quality. This is a particularly common problem in agricultural areas where a lot of fertilizer is used. In the long term, this can also worsen soil quality and reduce biodiversity.

It is important to take measures to reduce nitrate inputs to protect the environment and our health. This includes more conscious use of fertilizers and improved agricultural practices.

Health Risks of Nitrate in Drinking Water

Nitrate in drinking water can pose health risks. It can be particularly problematic for babies, as it is converted to nitrite in the body. This nitrite can impair the transport of oxygen in the blood and lead to what is known as cyanosis. Adults should also be vigilant, as high nitrate levels can increase the risk of certain types of cancer in the long term. It is therefore important to regularly check and monitor the nitrate concentration in drinking water to ensure that it remains below the recommended limits. If you live in an agricultural area, nitrate levels in the water could be higher, as fertilizers often contain nitrate. It is worth being vigilant and, if necessary, considering filter systems to improve water quality.

How to test and reduce nitrate in water?

To test nitrate in water, you can use test strips or digital meters. These tools are easy to use and provide quick results. Be sure to follow the instructions carefully to get reliable results.

There are several ways to reduce the nitrate content in water. One of the most effective methods is the use of water filters, such as reverse osmosis systems, which can efficiently remove nitrate. The use of ion exchangers can also be helpful. In the garden or in agriculture, you should reduce the use of nitrogen-containing fertilizers and rely on organic alternatives to minimize the entry of nitrate into the groundwater.

Regular testing and careful use of fertilizers help to reduce nitrate pollution in water in the long term.