Nitrate in drinking water - how dangerous is that really?

Again and again you can hear and read about the increased levels of nitrate pollution that cause concern to the public. Which risk by nitrate and nitrite actually exists, which areas are particularly affected in Germany, and why the limit value for nitrate in drinking water is actually inadequate alone, you can read here in detail.


Nitrates are salts of nitric acid (HNO3). They are very soluble in water and an important nutrient for plants. From protein degradation, nitrate is produced by bacteria via the detour via ammonium, and subsequently the nitrate is converted to nitrite.

This nitrogen cycle in the soil also exists in nature in the transformation and decomposition of organic material, the degradation products of which are then metabolized by the plants.

The production of nitrates is relatively easy and inexpensive possible. Most nitrogen fertilizers lead to an increase in nitrate concentrations in the soil, and thus to better plant growth.

Nitrates in drinking water

High nitrate levels in the soil lead to an accumulation of nitrates in near-surface groundwater. The more fertilized, the higher the nitrate content. In recent years, a significant increase in nitrate pollution of near-surface groundwaters has been observed in Germany.

The nitrate value in the groundwater does not only increase by the application of artificial nitrogen fertilizer, but also with fertilizer with slurry or liquid manure. In other cases, a high nitrate content of the water may also be an indication of contamination of the water with fecal matter.

The legal limit value of the Drinking Water Ordinance is 50 mg / l nitrate, in infants a value of 10 mg / l should not be exceeded. Especially in infants, a high nitrate intake can lead to disruption of oxygen transport.

Limit for water alone is not sufficient

However, limiting the nitrate content of water alone is not enough. The nitrate content of many vegetables is often far above the required limits of the Drinking Water Ordinance. For example, lettuce can contain up to 4,500 mg / kg nitrate, and fresh spinach is usually around 2,500 mg / kg. Even with frozen spins, the values ​​are on average around 2,000 mg / kg.
This corresponds to the multiple of the limit for water.

Health hazards due to nitrate

In addition to the obstruction of the iodine intake (possible consequences: thyroid disease, iodine deficiency and goiter) can also be due to increased nitrate intake for the conversion of nitrate into nitrite and in the carcinogenic nitrosamines in the stomach.

Nitrite deposits also cause circulatory problems due to occlusion of smaller vessels. In heavy metal compounds, nitrate causes additional health risks.

The risk of limiting the transport of oxygen is usually only in infants.

Particularly affected areas in Germany

Nitrate-contaminated groundwaters are found mainly in Lower Saxony and Schleswig-Holstein, also Saxony and Thuringia and the west of North Rhine-Westphalia are strongly affected. In Rhineland-Palatinate, too, there is a high burden in many parts, as well south of Mainz to Baden-Württemberg.

Tips & Tricks

Given the high load of fresh vegetables, the load on drinking water is almost secondary. So you do not have to worry too much.

Video Board: Public Health Impacts of Nitrate and Drinking Water Contaminants