Cyanides and their effect on the human body. Reference

13.06.2019

Potassium cyanide is one of the oldest poisons. It was used back in Ancient Egypt. It was also very popular in Medieval Europe.

The history of poisons and poisonings is rich and very interesting. Over thousands of years, an impressive arsenal of chemicals has been collected with the help of which you can easily send your neighbor to the next world. Potassium cyanide is far from the most powerful poison in existence, but it can certainly be called one of the most famous. And we have to thank the creators of detective and historical novels for this. The trouble is that the writers who described potassium cyanide poisoning in their works had little understanding of chemistry, which is why so many legends and myths arose around the poison.

Potassium cyanide belongs to a large group of chemicals that go by the collective—and somewhat arbitrary—name of cyanide. Despite its sinister fame, this compound is still used in household chemicals, for example, some paints and jewelry cleaners contain it. So theoretically, accidental poisoning is quite possible. Although, looking ahead, we note that this requires a lot of effort.

However, before moving on to a description of the effect of potassium cyanide on humans, I would like to say a few words about the features of this compound.

Chemical and physical properties of potassium cyanide, its applications

Potassium cyanide is a chemical substance whose formula is KCN. The reaction occurring between hydrocyanic acid and potassium hydroxide produces cyanide or a salt of hydrocyanic acid.

Appearance – small transparent crystals that resemble sugar. Potassium cyanide dissolves completely in water, forming a transparent, odorless solution.

Potassium cyanide or cyanide is a compound that is not resistant to decomposition. Stronger acid salts can push out the hydrocyanic acid and replace it. In this case, a new non-toxic chemical compound is formed.

Oxidation of a substance occurs when it comes into contact with air saturated with water vapor or when poison is added to a glucose solution.

There is a misconception that the smell of this toxic substance is similar to the strong smell of almonds, and severe potassium cyanide poisoning can be recognized by the “almond” breath of the victim.

In fact, the smell of this chemical compound (almond) can only be smelled by some people. In most cases, cyanide remains a substance that has absolutely no odor. Scientists explain this fact by the genetic characteristics of the human body.

Almond seeds do contain hydrocyanic acid, which, like all other cyanides, is very poisonous. But one seed contains such an insignificant amount of poison that you need to eat more than 200 of them to become poisoned.

Nowadays, potassium cyanide is used in a wide variety of industries. It is used for developing photographs, the chemical compound is used in the mining industry (for cyanidation), in the manufacture of paints for painting, in pharmaceuticals and for the preparation of various poisons for pests.

Where are cyanides found?

Potassium cyanide has found application in industry. Noble metals cannot themselves be oxidized by oxygen. Cyanide is used to speed up reactions. Third-party people not associated with factories and laboratories can become poisoned by poison. When toxic substances are released into the river from enterprises, no one is protected from the harmful effects. Cyanide is often used in darkrooms when cleaning jewelry with special substances. Interestingly, there are paints containing cyanide mixed with iron.

This poison cannot be found in nature. But there are compounds with its derivatives called amygdalin, which is found in the seeds of berries and fruits: plums, cherries, apricots, peaches. It is also found in almonds. When amygdalin breaks down, hydrocyanic acid is formed, the effect of which is no less dangerous for humans. Fatal poisoning can easily be caused by eating 100 grams of apricot kernels.

What dose of a substance causes a person to die, signs of poisoning

Potassium cyanide is a strong poison. Even in extremely small quantities it is hazardous to health. Cases of cyanide poisoning are extremely rare these days and can only occur in facilities where there is direct human contact with the substance (for example, in a laboratory).

The lethal dose is considered to be 17 mg/kg body weight. Death from such an amount of poison occurs within a few minutes. But this number is very arbitrary. It all depends on the route the poison enters the body, the health of the person and what the poison was taken with.

Smaller doses of potassium cyanide poison the body over a longer period of time.

The duration of action of a toxic substance also depends on the method of its entry into the human body. The vapors of this poison poison the body in the first seconds. If a small dose of cyanide enters the body through the stomach, the poisoning will make itself felt within a few minutes. The poison can also penetrate through the pores of the skin. This route is the longest; symptoms of poisoning appear only after an hour or two.

Provided that potassium cyanide enters the body through the stomach, its toxic effect depends on the food with which it was swallowed. Glucose (ordinary sugar) instantly oxidizes the compound of hydrocyanic acid and potassium salt. The poison becomes no longer dangerous. Laboratory workers whose work involves this substance have several lumps of sugar in their pockets. If the first symptoms of poisoning appear, they eat it to neutralize the cyanide.

The historical fact of Rasputin's poisoning is interesting. Potassium cyanide was added to his sweet drinks and sweet flour products. And, although the dose of poison was huge, the poison did not act immediately, since the abundance of food containing glucose did not allow the cyanide to instantly send Gregory “to the next world.”

If we take into account all the factors of poison entering the body (how it entered, the dosage of the substance, human health, the presence of glucose in the stomach), then there are several stages of acute poisoning:

• prodromal;
• dyspnoetic;
• convulsive;
• paralytic.

Each stage of poisoning is accompanied by certain symptoms. It all starts with banal weakness, sore throat and a feeling of tightness in the chest area. The second stage is characterized by increased weakness, pain in the heart and constant bitterness in the mouth. Nausea and vomiting may be present. The next two stages involve the entry of a large dose of potassium cyanide into the body. Death from poison occurs quickly without the necessary assistance. Symptoms include fainting, urinary incontinence, bowel movements, whole body convulsions, protruding eyes from the sockets, weakening and complete stopping of the heartbeat and breathing. The victim’s skin and mucous membranes also turn red, and an unhealthy blush appears on the cheeks. The next stage is death from potassium cyanide poison.

Effect on humans

Potassium cyanide has a rapid toxic effect. In case of hydrocyanic acid poisoning, serious changes occur in the human body - the production of one of the most important cellular enzymes called cytochrome oxidase is completely blocked.

This leads to a disruption of oxygen metabolism in the body; the cells do not receive enough oxygen, and the received oxygen cannot be fully absorbed. As a result, the process of oxygen starvation actively develops, which leads to cell death. The most severe consequences of intoxication can be death from asphyxia.

The severity of poisoning depends on the dose of the toxic substance taken:

1. 0.2 mg – death of the victim in the first 10-15 minutes.
2. 0.13 mg – death occurs within half an hour.
3. 0.1 mg – death within an hour after poisoning.

Cyanide intoxication can occur through the digestive organs - stomach, intestines or esophagus, as well as through mucous tissues, skin or respiratory tract.

Potassium cyanide poisoning. First aid

In order to provide first aid correctly, it is necessary to establish as quickly as possible the routes through which the poison enters the victim’s body. In any case, only a doctor can provide proper assistance after passing the necessary tests. Therefore, first of all, we call an ambulance. Before her arrival, a person with signs of poisoning can be taken outside. In the fresh air, cyanide poisoning usually gets better.

If the poison has penetrated the skin, then it is necessary to remove clothing, which may still contain the poisonous substance in its fibers. Wipe the victim with a solution of soap and water.

If potassium cyanide enters the body with food. It is necessary to take all measures to cleanse the stomach. Water solutions that can be used for washing can be made with potassium permanganate (0.1%), hydrogen peroxide (2%), and baking soda (2%). After induced vomiting, the person can be offered sweet tea or any other drink containing glucose.

If a person is unconscious. Monitor his breathing and heartbeat. If there is no heartbeat, it is necessary to perform an indirect cardiac massage. If a person stops breathing, perform artificial respiration. The person who did the artificial one should also consult a doctor to rule out possible poisoning from the victim.

Potassium - getting potassium

Potassium, like other alkali metals, is obtained by electrolysis of molten chlorides or alkalis. Since chlorides have a higher melting point (600-650 °C), electrolysis of straightened alkalis is more often carried out with the addition of soda or potash (up to 12%). During the electrolysis of molten chlorides, molten potassium is released at the cathode, and chlorine is released at the anode: K+ + e− → K 2Cl− − 2e− → Cl2

During the electrolysis of alkalis, molten potassium is also released at the cathode, and oxygen is released at the anode: 4OH− − 4e− → 2H2O + O2

The water from the melt evaporates quickly. To prevent potassium from interacting with chlorine or oxygen, the cathode is made of copper and a copper cylinder is placed above it. The resulting potassium is collected in molten form in a cylinder. The anode is also made in the form of a cylinder of nickel (for the electrolysis of alkalis) or of graphite (for the electrolysis of chlorides).

Antidotes. Treatment

To neutralize the effect of potassium cyanide, doctors use antidotes that work even in cases of severe poisoning with large doses of a toxic substance. And, since they all have different therapeutic effects, antidotes are used all at once.

1. glucose solution;
2. a solution of methylene blue (1%) in a solution of glucose (25%);
3. sodium thiosulfate solution (25%);
4. sodium nitrate solution (2%);
5. substances belonging to the group of methemoglobin formers;
6. amyl nitrite. They moisten cotton wool and bring it to the victim’s nose.

In addition to the above remedies, the patient is administered “Cytion” and “Lobelin”. These drugs have a stimulating effect on the respiratory center.

Symptoms of Cyanide Poisoning

The severity of symptoms depends on the amount of potassium cyanide consumed, therefore, acute and chronic stages of poisoning are distinguished. The lethal dose of cyanide is 17 mg per 1 kg of body weight . At a concentration of 10 to 15 mg, severe damage to internal organs occurs within 30–40 minutes. With a single dose of 50 mg, a person dies within 1 minute.

The lethal dose depends on the weight, age and health characteristics of the victim. There are several ways to be poisoned by potassium cyanide:

• in case of an emergency leak at the enterprise,
• in case of violation of storage rules in the laboratory or at home,
• when working with powder without protective equipment.

Another common method for producing a high dose of potassium cyanide is based on chemical reactions. Some people unknowingly keep the composition in a room with high humidity. When the critical norm of water in the air is exceeded, decomposition into components occurs, the formula is disrupted, senile hydrogen, sodium and toxic fumes are released, which remain in the room and settle on the mucous membranes and alveoli of the bronchi.

Knowing how potassium cyanide and toxic phthalates work, acute poisoning can be diagnosed by symptoms. There are several stages of development of intoxication:

• There is a headache, spasms in the temples, severe dizziness. When measuring the pulse, there is a noticeable increase in heart rate, the heart rhythm is disturbed, the skin on the face and chest turns red from a sudden rush of blood.
• Breathing becomes frequent and loud, adding a feeling of lack of air. The person tries to take a deep breath, but does not feel relief. The pupils dilate, practically do not react to light, and vomiting may occur.
• Lack of oxygen in the blood provokes fainting, limb cramps, and smooth muscle spasms. Poisoning with potassium cyanide increases the risk of a seizure with damage to the tongue.
• The patient is paralyzed, the reaction to pain and irritants completely disappears. As with a stroke, involuntary emptying of the intestines and bladder begins. Death from potassium cyanide occurs after excruciating agony from respiratory paralysis and death of brain cells.

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Important! During the Cold War, intelligence officers and secret agents had a miniature cyanide capsule sewn into the inside of their cheeks, which, when bitten, resulted in instant death and helped avoid torture and loss of important information.

Doctors explain what will happen if you drink potassium cyanide in a minimal dosage. The main blow falls on the liver, which diligently neutralizes toxic compounds. It protects hemoglobin cells and destroys their binding with poisons. In this situation, the symptoms are mild, the victim only feels dizziness and malaise.

It is more difficult to detect chronic potassium cyanide poisoning. When entering the blood daily, the particles settle in soft tissues, and the properties appear gradually. A person feels tired, and due to insufficient oxygen supply, he is overcome by drowsiness and absent-mindedness. Blood tests show a decrease in hemoglobin and an increase in liver tests.

Interesting facts about cyanide

What potassium cyanide is and its effect on humans has been known for a long time. In the 19th-20th century, despite the fact that potassium bluehydride is very poisonous, it was freely sold. Anyone, under the pretext of a pestilence of parasites, could purchase a deadly poison. So, in the famous detective stories of Agatha Christie, potassium syneride was purchased at the pharmacy. Moreover, the killer bought cyanide, saying that he would use it to bait wasps.

Only 40-60% of the world's population can smell cyanide. The seeds of bitter almonds (which are the source of the poison) are not eaten. Therefore, those people who can detect the smell will not always define the “almond” aroma of cyanide.

Effect on humans

Once inside people, the poison stops the work of the enzyme containing iron, which ceases to perform its functions. Oxygen continues to flow, but the cells do not perceive it. Oxygen starvation develops. The victim begins to choke, as in the case of suffocation. Organs stop functioning normally, which leads to death.

Cyanide poisoning occurs through the organs:

• Airways,
• skin,
• mouth and esophagus.

It is important to know

1. The lethal dose for humans is 1.7 mg/kg.
2. Slow absorption of the poison is possible if the victim’s stomach contains undigested food in the form of meat, eggs, and confectionery.
3. Glucose neutralizes small vapors of this toxin, so people working in production or laboratories are required to keep a piece of sugar in their mouth.
4. If a small dose of a toxin enters the body, it can still be saved if measures are taken in time.
5. When ingested through the esophagus, cyanide reacts with stomach acid, forming hydrocyanic acid. It affects the entire body.

Prevention of poisoning and possible consequences

Prevention of any poisoning is, first of all, caution. Working with such a dangerous poison as potassium cyanide is no exception. The use of masks and gloves is necessary to prevent direct interaction of the poison with open parts of the body.

At enterprises whose activities involve life-threatening conditions for workers, emergency drills and training of people in first aid are constantly carried out. It is necessary to always attend such events so that, in the event of an unusual situation, you do not get confused, act quickly and correctly provide assistance to the victim.

If the work is closely related to the use of any poisons, it is necessary to regularly go to the hospital for regular preventive examinations.

The consequences of poisoning with potassium cyanide can be observed with a large dosage of poison. Due to oxygen starvation of all cells of the body, disturbances in brain activity are quite likely.

After successful treatment, for quite a long time the victim may have nervous breakdowns, pain in the heart, surges in blood pressure, and tachycardia.

How does the poison work?

Biochemists note that a toxic chemical compound, entering the body, enters into a chain reaction with the blood at the cellular level. As a result, the work of the cellular enzyme cytochrome oxidase, which is responsible for the absorption of oxygen by tissue cells, is blocked. That is, there is oxygen in the blood, it circulates bound to hemoglobin, but is not absorbed at all. Without access to oxygen, all intracellular metabolic processes stop and the body dies. In fact, a person poisoned with potassium cyanide dies as if from lack of air. At the same time, his face will have a blush, his skin will have a light pink tint, and even the venous blood, due to the fact that, like arterial blood, will become saturated with oxygen, the color will not be burgundy, but scarlet.