NITRATE IN DRINKING WATER: A HOLISTIC VIEW
NITRATE IN DRINKING WATER: A HOLISTIC VIEW
The debate about nitrate in drinking water has become increasingly important in recent years. Experts and the German Environment Agency warn that rising nitrate levels in some regions of Germany could even increase water costs. In this article, we take a differentiated look at the topic of nitrate and provide information on the limit values and individual maximum quantities for different target groups, as well as options for filtering nitrate from drinking water.
Nitrate and health risks
Nitrates are salts of nitric acid (HNO3) and are soluble in water. They are used as mineral fertilizers in agriculture and thus get into our groundwater. Nitrate itself is not harmful to the human body. The problem arises when it is converted to nitrite in the body. Nitrite oxidizes the blood pigment hemoglobin to methemoglobin, which means that oxygen can no longer be properly delivered to the cell. This can lead to health problems, especially in infants. A recent study by the "Water Quality Association" from 2023 also found a correlation between high nitrate levels in water and certain diseases such as high blood pressure and certain types of cancer.
Limit values and recommendation
The World Health Organization (WHO) has determined that 3.7 milligrams of nitrate per kilogram of body weight per day is permissible. Children from the age of three should generally not consume more than 93 milligrams per day.
The current limit for nitrate in drinking water in Germany is 50 mg/l. However, some studies and experts argue that this value is too high and recommend lower limits, especially for risk groups.
The regulations of the German Groundwater Ordinance indicate that the federal government is aiming for a target value of 37.5 mg of nitrate per liter. In the USA, the Environmental Protection Agency (EPA) has established an enforceable standard, the so-called "maximum contaminant level" (MCL), for nitrates in water at 10 mg/l. The EPA assumes that a constant intake below this level should not cause any significant health problems.
Limit values by group as a guide:
General population: up to 10 mg/l harmless
Healthy adults: up to 37.5 mg/l harmless
Small children: Safe below 3 mg/l
People with colon cancer: Safe up to 4 mg/l
Infants: 0 mg/l
Filtering nitrate from water
There are various methods to filter nitrate out of water. Pure activated carbon filters, like the ones we use at LEOGANT, cannot influence the nitrate content in the water. If you want to remove nitrate from the water, you have the following options:
Using an ion exchanger with a special resin:
This involves exchanging the nitrate ions from the water with sodium. This effectively reduces the nitrate content in the drinking water, but increases the sodium content in the water. The exchange ratio is 1:1. So, if you want to remove 50 mg/l of nitrate, you artificially add 50 mg/l of sodium to the water. It should be noted that the water is no longer considered low in sodium from a value of 20 mg/l. Therefore, this type of nitrate reduction is not recommended for risk groups. In addition, with these ion exchange resins, nitrates can be released back into the water if they are overused, and there is a risk of poisoning.By filtering with reverse osmosis:
This is one of the most effective methods for nitrate removal. The reverse osmosis system removes almost all substances from the water, including nitrate. The disadvantage is that valuable minerals and trace elements are also removed. We recommend using reverse osmosis systems for nitrate levels that are significantly above the limit of 50 mg/l. If you decide to filter through a reverse osmosis system, we advise you to remineralize and revitalize the water after filtering, as water from a reverse osmosis system no longer has any biological quality and is more difficult for the metabolism to process. Demineralized water also no longer complies with the Drinking Water Ordinance.
Nitrates in food
Before worrying about nitrates in drinking water and resorting to more aggressive filtering methods due to excessive nitrate levels, it is important to first check your own eating habits.
People in Germany consume an average of about 90 milligrams of nitrate per day through their diet. For comparison: The daily limit for a 60-kilogram person is 222 milligrams of nitrate – according to the WHO, which recommends a maximum of 3.7 milligrams of nitrate per kilogram of body weight per day. Thus, adults do not exceed the limits on average.
The individual intake of nitrate therefore depends primarily on your own eating habits. The largest source of nitrate is nitrite, meat and sausage products (nitrite curing salt) and vegetables. Fertilization is not the only factor that influences the nitrate content in vegetables. Some types of vegetables store nitrates, while others accumulate very little. Leafy and root vegetables in particular, especially arugula and spinach, can have high nitrate concentrations of more than 1000 milligrams per kilogram. Fruit vegetables such as tomatoes, peppers, cucumbers, beans or peas usually have a nitrate content of less than 500 milligrams per kilo.
Tips for reducing the nitrate content in food
You can reduce the nitrate content in food by blanching or cooking vegetables before consumption. This results in a loss of 40–80 percent of the nitrate. When preparing leafy vegetables, remove stems, stalks, large leaf ribs and outer leaves. Light can also reduce the nitrate content in vegetables. Through photosynthesis, nitrates in the plant are reduced and converted into proteins. A higher light intensity and longer exposure times can therefore lead to plants consuming more nitrate. This process also takes place after harvesting.
Summary
Anyone who is concerned about the potentially high nitrate levels in their drinking water must first check their eating habits. As long as nitrite-containing sausage, meat and vegetables are on the menu, even a limit of 50 mg/l nitrate in drinking water can be neglected. This is because 500 mg and more can easily be absorbed through food. If you were to convert that into water, you would have to drink 10 liters of water with the maximum permissible value of 50 mg/l. A healthy adult does not have to worry about health effects if they consume higher amounts of nitrates from time to time. It only becomes problematic if you regularly consume increased nitrate levels via water and food.
In summary, a healthy adult does not have to worry up to a limit of 37.5 mg/l, provided the diet is low in nitrate. If you drink a recommended amount of 2.5 liters daily, you would consume 93.75 mg of sodium. This is only slightly above the WHO's recommended daily maximum amount of 90 mg. Our specified limit values apply to all other groups.
About the author:
Thomas Hartwig is a certified nutritional consultant and the founder of LEOGANT. For many years, he has been deeply involved with the element of water. He is a respected keynote speaker and guest on podcasts, where he shares his knowledge and experience. In his work, he combines insights from natural science and medicine with philosophical approaches to contribute to a holistic water awareness.