Of all the poisons, potassium cyanide has the most notorious glory. In detective novels, the use of this cyanide by intruders is a very popular way to get rid of unwanted persons. Obviously, the wide popularity of poison is also associated with its availability at the turn of the XIX-XX centuries, when the powder could easily be bought at the pharmacy.
And yet cyanide potassium is not the most dangerous and poisonous substance - it leaps after lethal doses to such prosaic poisons as nicotine or botulinum toxin. So what is cyanide potassium, where is it used and how does it affect the human body? Does his glory correspond to the real state of things?
What is potassium cyanide
The poison belongs to the group of cyanides - derivatives of hydrocyanic acid . The formula of potassium cyanide is KCN. The substance was first received by the German chemist Robert Wilhelm Bunsen in 1845, he also developed an industrial method for its synthesis.
In appearance, potassium cyanide is a colorless crystalline powder, readily soluble in water. In the manuals it is described that cyanide potassium has a specific smell of bitter almonds. But this characteristic is not always true - about 50% of people can smell this smell. It is believed that this is due to the individual differences in the olfactory apparatus. Cyanide potassium is not a very stable compound. Since hydrocyanic acid is weak, the cyano group is easily displaced from the compound by salts of stronger acids. As a result, the cyano group evaporates, and the substance loses its toxic properties. Also, cyanides are oxidized by accessing moist air or in solutions with glucose. The latter property allows the use of glucose as one of the antidotes for poisoning with prussic acid and its derivatives.
Where are cyanides contained
What is the use of cyanide potassium for man? It is used in the mining and processing industry and in galvanic plants. Since noble metals are not able to be directly oxidized by oxygen, solutions of potassium or sodium cyanide are used for catalyzing the process. Chronic poisoning with cyanide can be obtained by people and not related to production. Thus, at the beginning of 2000 there were cases of toxic emissions from mining and processing enterprises on the territory of Romania and Hungary to the Danube River, as a result of which people living around the floodplain were injured. The workers of special laboratories that come into contact with poison as a reagent are at risk of getting a chronic disease.
In domestic conditions, cyanides can be found in reagents for photolaboratories, in the means for cleaning jewelry. Small amounts of potassium cyanide are used by entomologists in insect stains. Also there are artistic colors (gouache, watercolor), which include cyanides - "Prussian Blue", "Berlin Azure", "Milos." There they are in conjunction with iron and give the dye a rich azure color.
What is cyanide in nature? In its purest form, you will not find it, but the connection with the cyano group - amygdalin, is contained in the bones of apricots, plums, cherries, almonds, peaches; leaves and elderberry shoots. During the cleavage of amygdalin, hydrocyanic acid is formed, which acts similarly to cyanide potassium. Lethal poisoning can be obtained from 1 gram of amygdalin, which corresponds to approximately 100 grams of apricot kernel kernels.
Effect of potassium cyanide on human
How does cyanide work on the human body? The poison blocks the cellular enzyme - cytochrome oxidase, which is responsible for the assimilation of oxygen by the cell. As a result, oxygen remains in the blood and circulates there in the form associated with hemoglobin. Therefore, when poisoning with cyanide, even venous blood has a bright scarlet staining. Without oxygen access, metabolic processes inside the cell stop and the body quickly dies. The effect is equivalent to the fact that if the poisoned simply suffocated due to lack of air.
Cyanide potassium is toxic when ingested, by inhalation of powder and solution vapors; It can also penetrate the skin, especially if it is damaged. The lethal dose of potassium cyanide for humans is 1.7 mg / kg body weight. The drug belongs to the group of potent toxic substances, its use is controlled with all possible severity.
The action of cyanides weakens in combination with glucose. Workers of laboratories, forced to come into contact with this poison while working, keep a piece of sugar behind their cheeks. This allows us to neutralize the microscopic doses of toxin that have accidentally entered the blood. Also, the poison is slowly absorbed into the full stomach, which allows the body to reduce its harmful effects by oxidation with glucose and certain other blood compounds. A small amount of cyanide ions, of the order of 140 μg in one liter of plasma, circulates in the blood as a natural metabolic metabolite. For example, they are part of the vitamin B12 - cyanocobalamin. And in the blood of smokers they contain twice as much.
Symptoms of cyanide poisoning
What are the symptoms of cyanide poisoning? The effect of the poison appears very quickly - when inhaled almost instantly, when it gets into the stomach - after a few minutes. Through the skin and mucous cyanides are absorbed slowly. The symptoms of cyanide poisoning depend on the dose received and the individual sensitivity to the poison.
With acute poisoning, the disorders develop in four stages.
Sore throat, scratching sensation;
- bitter taste in the mouth, the notorious aftertaste of "bitter almonds" is possible;
- numbness of the oral mucosa, pharynx;
- nausea and vomiting;
- feeling of squeezing in the chest.
The second stage is dyspnoeic, with signs of oxygen starvation increasing:
- chest pressure increases;
- the pulse slows down, weakens;
- general weakness grows;
- pupils are dilated, the conjunctiva of the eye turns red, the eyeballs protrude;
- there is a feeling of fear, turning into a deafened state.
When you receive a fatal dose, the third stage begins - convulsive:
- bite of the tongue;
- involuntary urination and defecation;
The fourth stage - paralytic, leads to death from cyanide potassium:
- the victim is unconscious;
- breathing greatly slows down;
- mucous membranes turn red, a blush appears;
- sensitivity and reflexes are lost.
Death occurs in 20-40 minutes (when the poison is ingested) from stopping breathing and heart. If the victims do not die within four hours, then, as a rule, they survive. Possible consequences are residual brain damage due to oxygen starvation.
In chronic cyanide poisoning, the symptoms are largely due to intoxication with thiocyanates (thiocyanates) - substances of the second hazard class, into which cyanides pass in the body under the influence of sulphide groups. Thiocyanates cause the pathology of the thyroid gland, detrimentally affect the liver, kidneys and provoke the development of gastritis.
The victim needs to introduce the antidotes of potassium cyanide as soon as possible, of which there are several. Before the introduction of a specific antivenom, it is necessary to alleviate the patient's condition - remove the poison from the stomach by washing:
- 0.1% solution of potassium permanganate;
- 2% solution of baking soda;
- 2% hydrogen peroxide solution;
- 5% solution of sodium thiosulfate.
Then give a sweet warm drink.
If the victim is unconscious, then only a medical worker can help him. In case of respiratory failure, an artificial ventilation of the lungs is performed.
In case there is a probability of getting cyanide on clothes, it is necessary to remove it and wash the patient's skin with water.
Take measures to maintain life - inject a respiratory tube and an intravenous catheter. Cyanide potassium is a poison to which there are several antidotes. Apply them all, because they have a different mechanism of action. The antivenom is effective even at the last stages of poisoning.
- Methemoglobin-forming agents cleave oxygen from hemoglobin and allow it to take the cyanide molecules from the cells. This group includes nitrogen oxides, nitrates and nitrites, nitroglycerin, amyl nitrite, methylene blue.
- Amyl nitrite is dripped on cotton wool and allowed to sniff every two minutes.
- Sodium nitrite is administered intravenously in the form of a 2% solution.
- Methylene blue 1% solution on 25% glucose solution intravenously.
At the same time, they are guided by the fact that the level of methemoglobin in the blood does not exceed 25-30%.
- Solutions of substances that easily release sulfur neutralize cyanide in the blood. Apply a 25% solution of sodium thiosulfate.
- A glucose solution of 5 or 40%.
To stimulate the respiratory center, drugs "Lobelin" or "Cititon" are administered.
Summarizing, we can say the following. The toxic effect of cyanide potassium on humans is to block the mechanism of cellular respiration, which results in death from suffocation and paralysis very quickly. Help can be medications-antidotes - amylnitrite, sodium thiosulfate, glucose. They are administered intravenously or inhaled.
To prevent chronic poisoning in production, general safety measures should be observed: avoid direct contact with the poison, use protective equipment, and regularly conduct medical examinations.