Limits for drinking water: nitrates – 50 mg/l (ppm), nitrites – 0.5 mg/l (ppm)
- No color
- No taste
- No odor or other manifestations
- Nitrates change in the digestive tract into nitrites
- Nitrites are toxic, especially for young children
- After nitrite intoxication, the ability of blood to transport oxygen is blocked – suffocating occurs
Removing nitrates from water
- Principle of ion exchange
Nitrates and nitrites were not naturally present in the water. With the rise of agriculture and the use of fertilizers, however, nitrates now occur quite commonly in both surface and underground waters. They can also come from leaking cesspools, fertilizers and other sources of waste water. Waste water treatment plants are equipped with nitrate degradation technology, and generally release concentrations significantly below the drinking water limit.
Nitrates as such are not directly harmful. In the human digestive tract (or in water by the action of microorganisms), they can be transformed into nitrites. Nitrites irreversibly damage hemoglobin responsible for oxygen transport in the blood. There is a so-called methemoglobinemia, which is characterized by convulsions, paralysis, dyspnoea and unconsciousness to death. Most at risk are small children (up to 6 months).
