Nitrate poisoning: symptoms and treatment, poisoning prevention
Jun 07, 2018
Summer and early autumn are the time of fresh vegetables and berries.But products of plant origin, despite all its usefulness, can also represent a danger to humans.This is possible if the vegetables contain a large number of chemical compounds nitrates.What you need to know in order not to get poisoning with nitrates?Table of contents: Why are nitrates dangerous?Doses of nitrates, dangerous to humans Nitrate content in plants Symptoms of nitrate poisoning Water-nitrate methaemoglobinemia in children Treatment of nitrate poisoning How to protect yourself from nitrate poisoning?
What are the dangerous nitrates?
Nitrates are ammonium salts.They are a component of the soil and are used by plants to synthesize the necessary ammonium.However, man's violent human activity led to an excessive accumulation of nitrates in the soil.This is all the result of the uncontrolled use of chemical nitrogenous fertilizers - saltpetre.
Vegetables and berries growing on the soil with a high concentration of nitrates actively absorb them.From this, the plant grows faster, becomes larger.When you use these vegetables, nitrates enter the human body.
The nitrates themselves are not dangerous at all.The introduction of nitrates into the blood of laboratory animals did not lead to any disturbances in the body.But when ingested in the gastrointestinal tract under the influence of microflora, nitrates are reduced to nitrite .It is these substances that are dangerous to humans.
Nitrite binds to hemoglobin and forms methemoglobin .The main function of hemoglobin is to transfer oxygen from the lungs to the tissues of the body.Methemoglobin is unable to perform this function, because of which tissues do not get oxygen to the fullest and oxygen deficiency develops.
It is also known that in adults, under the action of the enzyme methemoglobin reductase, methyhemoglobin is reversed into hemoglobin.That's why acute poisoning in adults, although it occurs, but not so often.However, a certain category of people is more prone to the emergence of nitrate poisoning.These are pregnant, elderly people, as well as persons with anemia, pathology of the respiratory and cardiovascular system.
But most susceptible to nitrate poisoning are children under three years old, especially in the first months of life.It turns out that the enzyme methemoglobin-reductase is weakly active in young children.That is, methemoglobin is not able to turn back into normal hemoglobin.
Nitrate dose, hazardous to humans
The maximum allowable dose of nitrates for an adult is 5 mg per kg of body weight, and for a child - not more than 50 mg.
Relatively easily, without occurrence of any disturbances, a person is able to transfer a daily dose of nitrates to 15-200 mg.It is believed that 500 mg is the maximum allowable dose, but 600 mg is already a really toxic dose for an adult.For the poisoning of the baby, it is enough for some 10 mg of nitrates.
In Russia, the allowable average daily intake of nitrates is 312 mg.Although in real spring it is able to reach 500-800 mg per day.
On the territory of the Soviet Union for the first time talked about the dangers of nitrates in the seventies, when in Uzbekistan there was a massive poisoning with nitrates when drinking watermelons grown on soil massively fertilized with nitrate.
Nitrate content in plants
In the minimum amount, nitrates are always present in plants.However, when the concentration exceeds the permissible levels, the plants become toxic.Nitrates accumulate mainly in root crops, roots, stems, petioles, large veins of leaves, peel.To a much lesser extent, they concentrate in fruits.Nitrates are much more in green, unripe fruits, than in ripe ones.The maximum concentration is maintained by plants during the ripening period.
Vegetable products are divided into three groups:
- The first group of is products with a high nitrate content( up to 5000 mg / kg).This group includes salad, spinach, beets, dill, cabbage, radish, green onions, melons and watermelons.
- The second group of is products with an average nitrate content( 300-600 mg).This includes color and white cabbage, zucchini, pumpkin, turnip, radish, horseradish, carrots and cucumbers.
- The third group of is products with a low nitrate content( 10-80 mg).This includes Brussels sprouts, peas, sorrel, beans, potatoes, tomatoes, onions, fruits and berries.
Symptoms of nitrate poisoning
Symptoms of poisoning occur when the concentration of methaemoglobin is more than 15%. Acute nitrate poisoning is indicated by the following symptoms:
- Cyanosis of the facial skin, especially in the nasolabial triangle, nails, visible mucous membranes;
- Nausea with vomiting, abdominal cramps;
- Diarrhea, often with impurities of blood;
- Increased liver size, her soreness in palpation;
- Headache, tinnitus, dizziness, drowsiness;
- Shortness of breath;
- Rapid heart rate;
- Impaired consciousness, right up to loss.
Important! Nitrate poisoning in children is very difficult.
Note: for chronic poisoning have nonspecific symptoms: weakness, fatigue, decreased ability to work, pallor of the skin.
It is also known that nitrates can interact with amines to form nitrosamines.These substances have a carcinogenic and mutagenic effect.
Water-nitrate methaemoglobinemia in children
People who drink water from decentralized sources are at risk of nitrate poisoning.The soil is contaminated with nitrates not only by chemical fertilizers, but also by the contents of sewage and cesspools.
Nitrates penetrate into the groundwater, and from there to the aquifer.In shallow wells, wells, drifts, water can be with increased water content.The upper limit for the content of nitrates in water is 50 gm / dm3.In some localities, the content of nitrates in water can be 10-20 times higher than the maximum permissible concentration.
Generally, water with a high content of nitrates does not cause disturbances in an adult, but it has serious consequences for young children.
The first cases of water-nitrate methaemoglobinemia are described in the middle of the 20th century.Children with artificial feeding had cyanotic skin, shortness of breath, palpitations.It turned out that the mixtures were prepared on water with a high concentration of nitrates.During the years 1949-1950, 278 cases of water-nitrate methaemoglobinaemia were registered in the United States, 39 of them were fatal.
Only in Russia every year hundreds of cases of nitrate poisoning are registered, some of them end up lethal.Now the country is monitoring the content of nitrates in water from decentralized sources.It is terrible to imagine what would be the incidence rates of water-nitrate methaemoglobinemia, if monitoring were not carried out.
When the concentration of methaemoglobin in children exceeds 10%, symptoms of poisoning appear.The child becomes sluggish, refuses to eat.Parents notice that the baby's skin becomes cyanotic, there is cyanosis of the nose, lips, visible mucous membranes.The baby develop shortness of breath and tachycardia.Vomiting, diarrhea does not always occur.With severe disease, when the concentration of methemoglobin exceeds 30%, the baby develops seizures, Chelin-Stokes pathological respiration occurs.Severe poisoning can lead to death.
To prevent poisoning, children should not be given water with excess of nitrates, cook food, mixtures on this water.Also, do not drink this water to women during pregnancy.
Treatment of nitrate poisoning
If a person has signs of nitrate poisoning, it is necessary to get him vomiting.To do this, you can give the patient a few glasses of salted water.At this time, you need to call an ambulance.
In hospital, the patient is administered intravenously an antidote of nitrite compounds - a solution of methylene blue.Also prescribed solutions of glucose, sodium thiosulfate and ascorbic acid.If necessary, oxygen therapy is carried out.
To restore tissue respiration, the patient is administered cocarboxylase, coenzyme A.
The tasks of treatment with nitrate poisoning are to accelerate the excretion of the poison from the body, to eliminate hypoxia, to restore hemoglobin.
How to protect yourself from nitrate poisoning?
You can prevent poisoning if you know the prevention measures.It is not difficult to follow them, but this will help to maintain health, and sometimes life.
Here are these simple recommendations:
- Vegetables and berries eat during the season, early unripened fruits contain nitrates in maximum concentration.
- Buy vegetables and berries in stores, supermarkets, where each lot is accompanied by documents indicating the content of nitrates.Buying watermelons at the road can not be sure that they are safe.
- Remember that nitrates in the water do not smell, do not taste.Determine their presence is possible only in a laboratory way.
- From nitrates in water it is impossible to get rid of by boiling or filters.
- When cleaning the plant, remove the most nitrate parts: in melons it is the part adjacent to the peduncle, and for cucumbers, beets, radishes - both ends.
- Soak the vegetables in water before using.This method allows to reduce the level of nitrates by 20-30%.
- The reduction of nitrates is observed during the heat treatment of products.Thus, when cooking, it is possible to reduce the level of nitrates in vegetables by approximately 60-80%.
- Since nitrates concentrate as much as possible in the skin of vegetables, it must be cleaned.This applies in particular to cucumbers and zucchini.
Grigorova Valeria, medical reviewer