What does hydrogen sulfide affect? Everything you need to know about hydrogen sulfide

Hydrogen sulfide is a colorless gas with an unpleasant rotten egg odor. It is formed as a result of contact of sulfur with hydrogen. In chemistry it is also called hydrogen sulfide or hydrogen sulfite. Chemical formula - H 2 S. It is quite rare in nature. So, today we will look at the effect of hydrogen sulfide on the human body.

Properties of hydrogen sulfide

Hydrogen sulfide is released during the dissolution of organic substances, during blasting operations in mines, as a result of oil and coal processing, as by-effect production of cellophane, paints, viscose, sugar. It enters the atmosphere in large quantities, polluting it. In landfills, hydrogen sulfide is formed when food waste rots. Since it is heavier than air, it settles in deep holes, ditches or even wells.

The gas is highly toxic. Highly flammable and explosive in combination with oxygen. It burns in the air with a bluish flame.

It also interacts well with strong oxidizing agents. On contact with metals it causes corrosion.

Hydrogen sulfide is the most active of the sulfur-containing elements.

A la "bad egg"

The gas has an extremely unpleasant smell of rotting protein. Toxicology studies the threshold of perception of a substance different people. It has been found that some are more sensitive to this smell than others. But this applies only to its small concentrations. If there is a lot of gas in the air, it simply paralyzes the olfactory nerve, and the “victim” ceases to feel the pungent odor.

Harm of hydrogen sulfide

The effect of hydrogen sulfide on the human body can be both positive and negative. Let's consider how dangerous it is and why.

Research on this gas began in 1998. Experiments were carried out on rats. But until now, the mechanisms of the influence of hydrogen sulfide on the human and animal bodies have not been reliably studied.

Hydrogen sulfide is known to be very poisonous. People who live near factories where it is used suffer from chronic poisoning. They experience weight loss and a metallic taste in the mouth. Deterioration of vision and even fainting indicate that a person is poisoned with hydrogen sulfide and needs urgent treatment.

Even 0.1% of the gas in the air leads to poisoning. This small concentration can kill within ten minutes, but often poisoning only causes severe symptoms. If the level is higher, just one breath can be fatal.

Symptoms appear:

• headache;
• dizziness;
• nausea;
• increase in pressure.

Attention! In the sewerage, the level of hydrogen sulfide reaches 16%!

The health hazards of hydrogen sulfide

The gas has a suffocating and irritating effect on the body. It causes irritation to the mucous membranes of the eyes and respiratory tract. It is the impact on the respiratory tract that is one of the most dangerous reactions that can lead to pulmonary edema. Penetrating into the body, it blocks the respiratory enzyme. The effect of hydrogen sulfide on the human body in the air is so harmful that it can cause instant death if its concentration is high.

Hydrogen sulfide has a detrimental effect on the protein hemoglobin. It converts iron, which is part of hemoglobin, into iron sulfide. As a result, the blood becomes black and loses, partially or completely, its ability to carry oxygen.

Irritation of the mucous membranes even with a small amount of hydrogen sulfide can lead to keratoconjunctivitis, rhinitis, bronchitis, and drooling.

The gas also has a negative effect on the nervous system. Hydrogen sulfide stimulates neuronal activity. It causes depression and anxiety. With prolonged inhalation of the gas, it is possible to develop mental disorders and lesions of the vegetative nervous system. Patients also suffer from insomnia.

Doses and symptoms of poisoning

Below we will consider the negative effect of hydrogen sulfide on the human body. Signs of poisoning vary. It depends on the amount of gas in the air.

When a small amount of the substance is inhaled, pain in the eyes, redness, coughing, pain in the chest, and wheezing in the lungs are observed. Poisoning is also accompanied by nausea, fatigue and headache.

Higher concentrations worsen the symptoms described above. It is also possible for the heart to deteriorate, pulmonary edema, bronchopneumonia, agitation or, on the contrary, fainting, and decreased blood pressure. The liver may enlarge and body temperature rises.

Severe poisoning causes loss of consciousness and even coma. Manifested by convulsions, hallucinations, respiratory and cardiac dysfunction. May end in death. With a favorable outcome, the symptoms are replaced by deep sleep. Later, asthenic syndrome develops. With proper treatment it disappears, but in some cases it is complicated by encephalopathy.

Very high concentrations of gas in the air cause instant death due to paralysis of the respiratory nerve and heart. In this case, irritation of the mucous membranes simply does not have time to develop.

However, the properties of hydrogen sulfide and its effect on the human body directly depend on the dose and method of application.

The benefits of hydrogen sulfide for blood vessels

Hydrogen sulfide is a poison, which, however, can heal. Moreover, a small amount of it is even present in our body. Scientists have long proven that the gas is formed in minimal concentrations in the stomach of people and animals. This function is genetically programmed. Mutation of the gene that regulates its production causes serious diseases - Parkinson's and Alzheimer's syndromes, atherosclerosis, hypertension.

The fact is that the gas affects the blood vessels, increasing their lumen. This helps reduce blood pressure and improve blood circulation. Injecting non-toxic doses of hydrogen sulfide into the body combats hypertension. At the same time, the gas prevents the development of atherosclerosis. This is due to the fact that cholesterol plaques are deposited only on the walls of damaged blood vessels. Hydrogen sulfide has an anti-inflammatory effect on them, protects the walls of blood vessels from loss of elasticity, and increases their resistance to damage.

Hydrogen sulfide and nerve cells

Hydrogen sulfide also has a positive effect on nerve cells. They are damaged by free radicals, which cause cancer, but the gas neutralizes them. Thus, it protects the brain from damage. It has been proven that in people suffering from brain diseases, the content of hydrogen sulfide in the body is lower than normal. In addition, it stimulates the nutrition of neurons and improves memory.

These data are confirmed by experiments on rats.

Does hydrogen sulfide improve erection?

In America, they continue to study the effect of hydrogen sulfide on the body of people and animals. In a Californian university clinic, cavernous bodies were taken for research (this biomaterial remains after sex reassignment operations). It turned out that the introduction of hydrogen sulfide relaxes smooth muscles. Subsequently, experiments on rats showed that the higher the dose of hydrogen sulfide, the longer the erection lasts. However, it is too early to say that the gas can be used as a new Viagra, since scientists have not yet figured out the mechanisms of its action.

Hydrogen sulfide and youth

Experts from a Chinese university recently reported that the effect of hydrogen sulfide on the body can be rejuvenating. The thing is that gas can activate the klotho gene. Klotho is responsible for longevity and also restores blood pressure.

In addition, the introduction of hydrogen sulfide stimulates the production of an enzyme called sirtuin. It prevents oxidative processes in the body and slows down its aging.

The benefits of hydrogen sulfide baths

The positive effect of hydrogen sulfide on the human body in water with the correct dosage is very great. The content of the substance in water may be minimal, but sometimes doctors prescribe fairly high doses. However, only a doctor can prescribe hydrogen sulfide baths.

The gas easily penetrates through the pores, mucous membranes and respiratory tract, entering the bloodstream. It spreads through the blood throughout the body, stimulating its work. Result of hydrogen sulfide baths:

• increasing immunity;
• improving blood circulation and reducing blood pressure;
• healing of skin lesions;
• elimination of inflammation;
• normalization of carbohydrate metabolism;
• reduction of cholesterol in the blood;
• acceleration of metabolic and oxidative processes;
• normalization of the functions of the central and autonomic nervous system;
• improving the functions of the skeletal system.

Baths are indicated for a huge range of diseases, including urological, gynecological and endocrine. In addition, they are able to treat even severe intoxications (for example, after mercury poisoning). These baths treat skin, muscles, tendons, and bones. However, they have many contraindications.

The duration of such a session is from 8 to 12 minutes. The course of treatment usually does not exceed 12 sessions. Therapeutic baths are taken every other day.

So-called half-baths with hydrogen sulfide are also popular in sanatoriums. Usually this water procedures for arms or legs. Also, water enriched with this substance is used for rinsing the mouth and hair. They wash their faces with it and make compresses and lotions from it.

Hydrogen sulfide acid is also used in cosmetology - a solution of this substance helps eliminate acne, tighten the skin and reduce the appearance of cellulite.

Attention! A hydrogen sulfide bath can only be carried out in specialized rooms where there are powerful air purifiers. Otherwise, intoxication from hydrogen sulfide vapor can be fatal.

Conclusion

So, today we looked at the effect of hydrogen sulfide on the human body. We briefly discussed its benefits and harms. Like many poisons, it is actively used in medicine and cosmetology, but in high doses it is very dangerous. This proves that it can only be used externally under medical supervision.

This is not the first time that residents of the capital have wondered why they smell of hydrogen sulfide. Complaints to Rospotrebnadzor, the Ministry of Emergency Situations and other authorities are regularly received from Muscovites. People suffer from the unpleasant aroma of either sour cabbage or rotten eggs, which appears in waves in different parts of the city and interferes with normal work and rest.

Emission sources:

In the process of searching for the source of the stench, different versions appeared in the media, some of them very unusual. None have been confirmed yet:

• Cleanup work at landfills in Nekrasovka and Kuchino. To date, these versions have not been confirmed.
• A release at a meat processing plant on Volgogradsky Prospekt.
• Soil liquefaction in the capital due to the movement of the Russian Platform. Through faults, gases, including chemically aggressive ones, escape to the surface from the very depths of the Earth. This is the opinion of the chief geologist of the regional geochemical research party of the VIMS branch, candidate of geological and mineralogical sciences Anatoly Pronin.
• A completely unusual version of the source of the emission is being put forward on social networks. The process of active materialization of demonic entities. And the reason is ritual sacrifices. By the way, this version is also supported by the fact that eyewitnesses noted the smell of not exactly hydrogen sulfide, but sauerkraut and burnt bones. This is what causes the smell of sulfur and rotten cabbage, as well as sudden fluctuations in the weather (in a matter of hours, for example).

So what is hydrogen sulfide? Where does it come from and is it safe for humans?

Characteristics of hydrogen sulfide

Hydrogen sulfide is a colorless gas with the smell of rotten eggs. Formed during the decomposition of organic matter.

Hydrogen sulfide is heavier than air, but lighter than water, so it can accumulate in ditches, ravines, pits and contaminated wells.

Chemical formula - H2S

Physical properties of hydrogen sulfide

Melting point - 85.5°C, boiling point - 60.7°C. Thermally stable, but at temperatures above 400°C it decomposes into simple substances- S and H2.

When exposed to H2S, metals become coated with a coating of sulfur compounds. This does not apply only to noble types of gold and platinum.

Sources of hydrogen sulfide

Natural springs:

• in small quantities in natural gas,
• is part of associated petroleum gas,
• as part of gaseous volcanic emissions,
• present in sulfur springs (Matsesta, Pyatigorsk),
• in deep layers of sea water.

Hydrogen sulfide is formed where proteins containing cysteine ​​or methionine rot. Surprisingly, it is present in the intestinal gases of humans and mammals.

IN major cities As a rule, there are industries whose by-product is hydrogen sulfide. Such industries include enterprises for oil and coal refining, wastewater treatment, production of paints, cellophane, sugar, viscose, etc.

The effect of hydrogen sulfide on the human body

Hydrogen sulfide is a dangerous toxic chemical for humans in large quantities. This is a very insidious substance, since a person feels only small concentrations of gas in the air, and at high concentrations, the receptors cease to recognize it.

A small amount of hydrogen sulfide is constantly present in the human body; it is formed during the decay of proteins in the intestines.

Why is hydrogen sulfide dangerous?

Inhalation of large concentrations of H2S, as well as introduction into the body large quantity sulfur salts are harmful to health. When the hydrogen sulfide content in the air is 0.1%, a person dies within 10 minutes.

Hydrogen sulfide has a local and general effect on humans.

The overall effect is manifested in the inhibition and paralysis of cellular respiration.

This gas easily reacts with iron ions contained in hemoglobin molecules. As a result, iron sulfide is formed, which turns the blood black and loses its ability to transport oxygen.

Local effects are expressed by irritation of the conjunctiva, nasal mucosa, pharynx and respiratory tract. A person experiences a burning sensation, lacrimation, coughing, hoarseness, and may develop a fear of light.

With prolonged exposure to hydrogen sulfide, the body may develop chronic conjunctivitis, inflammation of the eyes, erosion and opacification of the cornea, bronchitis, rhinitis, drooling and laryngitis.

Symptoms of hydrogen sulfide poisoning

Small but frequent exposure to hydrogen sulfide on the body contributes to the appearance of symptoms of chronic poisoning:

• anemia,
• weight loss,
• irritability, sleep disturbance, headaches,
• dyspepsia.

Stages of poisoning and treatment

There are three stages of hydrogen sulfide poisoning.

In the mild stage, a rush of fresh air, rest, analgesics, vitamins with iron and eye drops with novocaine are enough for a person to recover.

In case of moderate or severe poisoning, when dizziness, cyanosis, vomiting, suffocation, and heart rhythm disturbances are observed, hospitalization and treatment with intravenous injections with mytilene blue or chromosmon are required.

In addition, for cyanosis, heart failure, and heart rhythm disturbances, injections of caffeine, cordamine, and norepinephrine are given. In case of coma, resuscitative therapy is performed.

How to measure hydrogen sulfide concentration?

It is very simple to measure the amount of hydrogen sulfide in the air of your apartment by installing a small device called ANKAT-7631 at home. The device is configured so that when the gas limit is exceeded, a sound signal is issued.

In addition, you can invite special services to measure hydrogen sulfide in the indoor air.

Treatment with hydrogen sulfide

Hydrogen sulfide is dangerous only in high concentrations; in small doses it is even useful and is used in medicine. Doctors often prescribe hydrogen sulfide baths for therapy; do not be alarmed - they are useful and absolutely safe.

Hydrogen sulfide is simply necessary for the occurrence of certain physiological processes, for example, the functioning of the heart and blood vessels, an important element for the nervous system and memory function, promotes erection, and is a good antispasmodic.

The body's production of hydrogen sulfide is genetically programmed. If a mutation occurs in the gene responsible for this process, diseases such as hypertension, atherosclerosis, Alzheimer's and Parkinson's disease may appear.

Research into the effect of hydrogen sulfide on the body, which began back in 1998, is still ongoing, since many of the mechanisms of its effect have not been fully disclosed. But it is already reliably known that hydrogen sulfide is involved in the processes of vasodilation and the transmission of nerve impulses.

Why does the water smell like hydrogen sulfide?

There are hydrogen sulfide sources that can be used in water extraction. Bottled water released from such sources may have a hydrogen sulfide odor.

Translation of an article by Rui Wang. Rui Wang - Professor of Biology and Vice President for scientific work Lakehead University, President of the Canadian Physiological Society, a leading expert in the metabolism and physiological functions of low molecular weight gases that play the role of gaseous mediators - including nitrogen monoxide, carbon monoxide and hydrogen sulfide.

Scientists have shown that hydrogen sulfide (H2S), a gas that is poisonous in large quantities, is formed in small doses in the body and performs many functions important for normal life.

Some of them are given below. However, H2S can also have pathological effects: for example, in excessive amounts it reduces insulin production, and there is evidence of its anti-inflammatory effects.

Imagine walking through the emergency department of a hospital with its walls shining with cleanliness, thoroughly washed with a disinfectant solution - and suddenly you hear the characteristic fetid smell of rotten eggs!

This situation seems incredible, but the source of the odor - hydrogen sulfide (H2S) - may in the near future become an integral part of any emergency department.

The toxicity of hydrogen sulfide (H2S) to humans has been known for centuries. Currently, this gas ranks first on the list of toxic substances during the extraction, pumping and processing of oil and gas. We begin to smell it at a concentration in the air of 0.0047 ppm.

At a concentration of 500 ppm, hydrogen sulfide causes breathing problems, and at a concentration of 800 ppm it causes death in five minutes. At the same time, surprisingly, hydrogen sulfide is essential for life.

In order to understand how the foul-smelling gas became an important component of physiological processes, let’s move back in time 250 million years.

Then, at the end of the Permian period, life on Earth was hanging on by a thread - the so-called great extinction occurred, which became one of the major disasters in the history of our planet.

According to the most common hypothesis, it was caused by the release of carbon dioxide during massive outpourings of volcanic rocks in Siberia, which triggered a chain reaction of environmental changes and led to a critical decrease in oxygen levels in the waters of the World Ocean.

These shifts in ocean composition were detrimental to aerobic (oxygen-consuming) marine species, but allowed anaerobic organisms, particularly green sulfur bacteria, to flourish.

The rapid proliferation of such bacteria has made the ocean completely unsuitable for the last aerobic species, because sulfur bacteria produced hydrogen sulfide in large quantities. Eventually, apparently, this poisonous gas began to be released into the air, destroying land plants and animals. By the end of the “great extinction”, 95% of marine animal species and 70% of land animals had died.

Perhaps the role of hydrogen sulfide in physiological processes in humans is a legacy of those ancient times. Only species capable of surviving in an atmosphere of hydrogen sulfide, and sometimes consuming it, were able to survive the “great extinction.” Apparently, this ability has been preserved to some extent in our country.

Trusting your sense of smell

Hydrogen sulfide (H2S) is not the only toxic gas involved in physiological processes in humans. In the 1980s Evidence began to appear that the body produces nitrogen monoxide NO in small quantities. It soon became clear that it plays the role of a mediator - a signaling molecule that affects cell functions.

Work awarded the Nobel Prize in Physiology or Medicine for 1998 showed that nitrogen monoxide is involved in many physiological processes, in particular in the regulation of immune responses and in the transmission of signals between neurons, and also causes vasodilation. Subsequently, similar functions were discovered for carbon monoxide (CO), a deadly, colorless and odorless substance commonly known as carbon monoxide.

Study of the physiological role of CO and NO

Research into the physiological role of CO and NO led me to the belief that other gaseous mediators may exist in the body. As a result of constant thoughts on this topic, in the summer of 1998, the idea finally occurred to me that H2S could be such a mediator. Returning from work one day, I noticed an unpleasant smell in the house.

It turned out that it came from the glass cabinet where our family heirlooms were kept, namely a spoiled Easter egg that my eldest daughter had painted for school homework.

At that moment, a question arose to me: if hydrogen sulfide is formed in rotten eggs, then could it not be produced in human organs and tissues?

Since my research on CO and NO focused on the effects of these gases on the cardiovascular system, I decided to conduct a similar study on the effects of H2S. The choice turned out to be successful.

Hydrogen sulfide is found in blood vessels

In the first experiments carried out by our team, it turned out that hydrogen sulfide is contained in small concentrations in the blood vessels of rats. Since the physiological characteristics of rodents and humans are very similar, it could be confidently assumed that this gas is also formed in human vessels.

This discovery inspired optimism, however, to draw conclusions about the physiological role of H2S, simply stating the fact of its presence in the vascular wall was clearly not enough.

At the next stage, it was necessary to investigate the mechanisms of hydrogen sulfide formation.

Cystathionine gamma lyase enzyme

Our attention was drawn to the enzyme cystathionine gamma lyase, which is involved in the formation of H2S in bacteria. Previous work has shown that it is found in the liver, where it plays a role in the formation of some sulfur-containing amino acids (the building blocks of proteins).

At the same time, there was no evidence of the presence of cystathionine gamma lyase in the vascular wall. As expected, we received such data. It turned out that in blood vessels, under the action of cystathionine gamma-lyase, hydrogen sulfide, ammonia and pyruvic acid are formed from the amino acid L-cysteine.

What role does this gas play in the vessels?

So, the source of H2S in the vascular wall has been identified. Now it was important to find out what role this gas plays in the vessels. Knowing that NO causes relaxation of vascular muscles, we hypothesized that H2S could act in the same way. This hypothesis turned out to be correct: when immersed in a solution containing hydrogen sulfide, the rats' blood vessels dilated.

As a result of all the work carried out, it seemed that H2S, like NO, is involved in the regulation blood pressure. At the same time, the molecular mechanisms of H2S action remained undiscovered. The first data on such mechanisms were obtained by us in studies on isolated vascular cells and published in 2001.

These data turned out to be quite unexpected: while NO causes vascular relaxation by activating the smooth muscle enzyme guanylate cyclase, then H2S causes the same effect in a completely different way.

Under the influence of this substance, the permeability of the so-called ATP-dependent potassium channels (KATP) increases - protein complexes built into the membrane of cells (in particular, vascular smooth muscles) and allowing potassium ions to pass through. As a result, the release of potassium from the cell increases, its charge changes, which leads to a decrease in the permeability of other calcium channels. As a result, the entry of calcium into the cell is reduced, and this leads to relaxation of smooth muscles and dilation of blood vessels.

It's time to move from isolated cells to intact animals. In our experiments, administering a hydrogen sulfide solution to rats led to a decrease in blood pressure, apparently due to dilation of the arteries and a decrease in resistance to blood flow.

Thus, increasing evidence suggested that H2S is involved in the regulation of blood pressure by causing vascular relaxation. However, it was still necessary to prove that the effects of the gas when introduced from the outside and when produced in the vascular wall are identical.

To investigate the natural effects of H2S, we bred a line of mice with an inactivated (“knocked out”) cystathionine gamma lyase gene. In such animals, H2S is, of course, not formed in the vessels. Then, for five years, we studied mice together with teams led by Solomon Snyder from Johns Hopkins University and Lingyun Wu from the University of Saskatchewan (Canada). Our efforts were not in vain.

In 2008, we published a detailed paper in which we showed, in particular, that in our rodents, as they age, the blood vessels narrow and blood pressure (measured using miniature cuffs placed on the tail) increases significantly. When hydrogen sulfide was administered to such mice, the pressure decreased.

The data from our work left no doubt that H2S plays a key role in the regulation of blood circulation. In addition, they made it possible to resolve one of the long-standing mysteries of physiology. The fact is that for a long time after the Nobel Prize-winning work on NO research, it was known that the action of this substance alone cannot fully explain the dilation of blood vessels.

Thus, in animals with inactivated genes responsible for the formation of NO in endothelial cells (the inner lining of blood vessels), peripheral vessels still retain the ability to relax. However, the nature of the vasodilator factor remained mysterious.

According to our data, this factor is H2S. In our first studies, we discovered the enzyme cystathionine gamma-lyase, which is responsible for the formation of hydrogen sulfide, in smooth muscle cells, but later it was found in the endothelial cells of mice, cows and humans - and even in larger quantities than in smooth muscles. It remains unclear what the relationship is between the vasodilatory function of NO and H2S, although some data suggest that NO causes predominantly relaxation of large vessels, and H2S - small ones.

New super drug?

The discovery of hydrogen sulfide synthesis in blood vessels and its role in the regulation of blood pressure has attracted the attention of many researchers looking for new ways to protect the heart from ischemic damage (i.e. damage caused by a decrease in blood supply, and therefore oxygen delivery).

A typical example of such damage is myocardial infarction, when the vessel supplying the heart is blocked by a thrombus, and the death of the part of the heart supplied by this vessel occurs. In 2006, Gary Baxter, now at Cardiff University in Wales, and co-authors published a paper that provided the first evidence of a beneficial role for H2S in ischemic heart injury.

The work used isolated rat hearts supplied not with blood, but with an oxygenated saline solution. The model of ischemic damage was the cessation of the flow of such a solution through one of the coronary arteries (vessels supplying the heart). It turned out that adding H2S to the solution a few minutes before blocking the artery reduced the size of the damaged area.

A year later, David Liefer of Emory University showed that genetically engineered mice with increased production of hydrogen sulfide in the heart were better able to withstand myocardial ischemia caused by coronary artery occlusion and were more resistant to the damage that often occurs after blood flow is restored (called reperfusion injury).

These and other data suggest that H2S may be used to prevent and treat hypertension, myocardial infarction and stroke. In addition, the vasodilating effect of hydrogen sulfide can be used in other conditions associated with disorders of vascular function, for example, erectile dysfunction (erectile dysfunction). It is known that the basis of erection is the dilation of the vessels of the penis and an increase in blood flow to it.

The effect of Viagra is due precisely to the fact that it increases the duration of the dilating effect of NO on blood vessels. There is evidence that H2S can have a similar effect, although the role of this substance in the human male reproductive system has yet to be studied (it is known, for example, that CO is produced in the tissues of the penis, but this gas does not promote erection, but ejaculation).

Hydrogen sulfide is produced not only in the heart and blood vessels. It is also formed in the nervous system, only under the action not of cystathionine gamma lyase, but of another enzyme - cystathionine beta synthase. The function of H2S in the nervous system is unclear. According to some data, it can play the role of a neuromodulator - a substance that increases or decreases the excitability of neural circuits. It is possible that H2S is involved in long-term potentiation, a process that facilitates communication between neurons and plays a role in learning and memory.

It has been shown that under the influence of hydrogen sulfide in nerve cells, the level of the antioxidant glutathione increases, which protects cells from the action of damaging factors. Finally, H2S may play a role in pain perception, which mediates responses to noxious stimuli.

In addition, hydrogen sulfide can affect metabolism, i.e. biochemical processes that ensure the production and use of energy, and the synthesis of substances. In surprising experiments, Mark Roth and his colleagues from the University of Washington showed that inhalation administration of small doses of H2S to mice leads to a slowdown in metabolism and, thereby, to the progression of certain diseases.

The heart rate of such mice immediately after the start of inhaling H2S dropped by half, and they went into a state of suspended animation: metabolic processes decreased so much that inhaling oxygen and H2S was enough for the animals to survive without any negative consequences.

It seemed that during such hydrogen sulfide anabiosis, metabolism was maintained at a minimum level for vital organs until normal energy supply was restored.

30 minutes after stopping H2S inhalation, the metabolic rate was restored.

If hydrogen sulfide suspended animation turned out to be effective and safe in humans, then it could become a powerful method of emergency care. Giving H2S inhalation to car accident victims or myocardial infarction patients could save time needed for transport to hospital and specialized care.

With the help of hydrogen sulfide, it would be possible to maintain those in need of transplantation in a state of suspended animation until they receive a donor organ - moreover, it would be possible to prolong the viability of the donor organs themselves.

One can imagine the use of H2S in areas of military conflicts or natural disasters: inhalation of this gas could delay the emergency of blood transfusions until sufficient quantities of the latter are delivered. Inhalation of hydrogen sulfide significantly increases the survival rate of rats with a loss of 60% of blood: rats receiving H2S survived in 75% of cases, and control ones - only in 25%.

Cautious optimism

However, one should not assume that hydrogen sulfide is an ideal cure for all diseases. There are still debates, for example, about whether it alleviates or aggravates the course of inflammation. Our laboratory and others have shown that H2S plays an important role in the development of diabetes mellitus I, a form of the disease that often begins in childhood and leads to lifelong dependence on insulin injections.

It turned out that H2S is formed in the so-called beta cells of the pancreas, which secrete insulin, and in animals with diabetes mellitus I, the production of hydrogen sulfide in such cells is sharply increased. This leads, firstly, to the death of a large number of beta cells, and secondly, to the suppression of insulin release by the remaining beta cells. As a result, insulin secretion drops to a level insufficient for the normal breakdown of glucose. Thus, H2S may be one of the culprits for decreased blood insulin levels during diabetes mellitus I.

Some of the beneficial effects of H2S in rats and mice are not replicated in larger animals. Thus, in 2007, French researchers showed that when inhaled with H2S, sheep, unlike rodents, do not fall into a state of suspended animation.

In another study, inhalation of H2S in piglets led not to a decrease, but to an increase in the rate of metabolic processes.
Even if it is possible to induce hydrogen sulfide suspended animation in humans, it is unknown whether it will lead to disturbances in brain activity. True, such disorders have not been identified in laboratory animals, but it is difficult to transfer such data to human mental functions. It is not yet clear whether higher functions such as memory and thinking can be preserved under conditions of hydrogen sulfide anabiosis, when life is barely warm.

And yet, the great therapeutic potential of hydrogen sulfide is of increasing interest to pharmacologists. Several companies are already developing drugs that release this gas in the body. Thus, the Italian company CTG Pharma has created drugs that combine the properties of non-steroidal anti-inflammatory drugs (NSAIDs) and H2S carriers.

Animal experiments have shown that such drugs can be effective in treating inflammatory diseases nervous system and gastrointestinal tract, erectile dysfunction, coronary heart disease and blood vessel diseases. And the company Ikaria (New Jersey), one of the founders of which is Mark Roth, recently began phase II clinical trials (clinical effectiveness studies) of an injectable form of H2S (more precisely, Na2S) in patients with coronary heart disease or those preparing for heart or lung surgery .

Work over the past decade has shown that hydrogen sulfide, whose smell makes us naturally disgusted, is extremely important for the normal functioning of the heart, and perhaps also the brain and other organs. It is possible that it also has other, not yet known effects. All this opens up new horizons in understanding the molecular foundations of human physiology and health. The study of the effects of H2S is just beginning, but there is already every reason to believe that someday it will offer new ways to combat today’s incurable diseases.

Hydrogen sulfide H2S- the most active of the sulfur-containing compounds. IN normal conditions a colorless gas with an unpleasant odor of rotten eggs. Very poisonous: acute human poisoning occurs at concentrations of 0.2-0.3 mg/l, concentrations above 1 mg/l are fatal. Hydrogen sulfide is highly soluble in water. The range of explosive concentrations of its mixture with air is quite wide and ranges from 4 to 45% vol. In contact with metals (especially if the gas contains moisture) it causes severe corrosion. The most undesirable component in oil refinery gases.

The danger of hydrogen sulfide to humans.

Hydrogen sulfide is a very toxic gas that acts directly on the nervous system. On the danger scale it is classified as class 3. Be sure to take this fact into account whenever you smell its distinct scent. But what is especially dangerous is the property of hydrogen sulfide to dull the olfactory nerve, which is why a person simply ceases to distinguish between the toxic vapors surrounding him, and intoxication can occur suddenly.

The lethal concentration of this gas in the air is very small - only 0.1%. This amount of hydrogen sulfide can kill a person in 10 minutes. One has only to increase concentration a little - and death occurs instantly, after the first breath. For example: in the sewer system the concentration of hydrogen sulfide sometimes reaches 16%.

The most noticeable signs of severe hydrogen sulfide poisoning are: pulmonary edema, convulsions, nerve paralysis, and subsequent coma. If the atmosphere contains hydrogen sulfide in smaller quantities (from 0.02%), the symptoms are not so fatal, but very unpleasant: dizziness and headache, nausea and fast addiction to the smell of “rotten eggs”.

People who work or live in close proximity to factories with hydrogen sulfide emissions experience what is called chronic H2S poisoning. At the same time, they begin to feel worse, experience headaches, rapidly lose weight, cases of fainting become more frequent, and a metallic taste appears in the mouth. Hydrogen sulfide also has a negative effect on vision, affecting the mucous membrane of the eye and causing conjunctivitis and photophobia.

Hydrogen sulfide poisoning can be cured if the necessary measures are quickly taken: take the victim into fresh air, enrich his lungs with oxygen, administer cardiac and respiratory analeptics, iron supplements, glucose, and vitamins.

MPC (Maximum Permissible Concentration)

Maximum permissible concentration of hydrogen sulfide (H2S) in the air in the work area is 10 mg/m3 (GN 2.2.5.1313-03 Maximum permissible concentrations (MPC) of harmful substances in the air of the work area), in a mixture with hydrocarbons—3 mg/m3.

The maximum permissible concentration of hydrogen sulfide (H2S) in the air of populated areas is 0.008 mg/m3 (GN 2.1.6.1338-03 Maximum permissible concentrations (MPC) of pollutants in the atmospheric air of populated areas).

A noticeable odor of hydrogen sulfide is observed at a hydrogen sulfide concentration of 1.4–2.3 mg/m3, a significant odor at 4 mg/m3, a severe odor at 7–11 mg/m3

Toxicology.

Very toxic. Inhaling air with low levels of hydrogen sulfide causes dizziness, headache, nausea, and with significant concentrations leads to coma, convulsions, pulmonary edema and even death. At high concentrations, a single inhalation can cause instant death. When inhaling air with small concentrations, a person quickly adapts to the unpleasant smell of “rotten eggs”, and it ceases to be felt. A sweetish metallic taste appears in the mouth.

When inhaling air with a high concentration, due to paralysis of the olfactory nerve, the smell of hydrogen sulfide almost immediately ceases to be felt.

How it is formed.

In nature, it is found quite rarely in the composition of associated petroleum gases, natural gas, volcanic gases, and in dissolved form in natural waters (for example, in the Black Sea, layers of water located deeper than 150-200 m contain dissolved hydrogen sulfide). It is formed during the decay of proteins, only those that contain the sulfur-containing amino acids methionine and/or cysteine. A small amount of hydrogen sulfide is found in the intestinal gases of humans and animals. Also found in crude oil.

Hydrogen sulfide, depending on the concentration, has both positive and negative effects on the vital activity of the body and its physiological processes. This chemical compound can be formed in internal environments or come from the external environment. The effect of hydrogen sulfide on the human body is multifaceted, both beneficial and poisonous, capable of causing instant death.

What is hydrogen sulfide and its beneficial properties

Hydrogen sulfide (hydrogen sulfide) is a colorless gas, sweetish in taste, with a strong distinct odor, smells like rotten eggs. The substance is poorly soluble in water, but soluble in alcohol, which is heavier than air. The gas is highly flammable when in air at a concentration of 5 to 45%. Burns in the air with a bluish flame.

Hydrogen sulfide is common in water natural conditions, for example, in seas at a depth of 150-200 m.

The substance is formed during the decay of protein compounds that contain amino acids with sulfur. Hydrogen sulfide is produced in small quantities in the human intestine.

Endogenous hydrogen sulfide produced in the body is important for normal physiological processes. It takes an active part in the synaptic transmission of nerve impulses. It has a positive effect on the brain, promotes memory development and the perception of new information.

The gas is an antispasmodic, when used it relaxes blood vessels small caliber and smooth muscles of hollow organs. Therefore, hydrogen sulfide is a prevention of the development of cardiovascular pathology.

The substance regulates intracellular metabolic processes.

In small volumes it acts as an antioxidant and reduces the severity of tissue inflammation.

When it enters the blood, the toxic substance destroys hemoglobin, the released iron reacts with H 2 S, and black sulfite is formed. It turns the blood dark.

Toxic effect of gas

Hydrogen sulfide in the air is dangerous to humans (hazard class 2). The gas enters the body through inhalation and transdermal (through the skin) routes.

External sources of toxic substance:

• solid and liquid waste landfills in which decay processes are actively taking place;
• cesspools, sewers, water treatment plants, tunnels;
• oil refining, chemical and gas industries;
• enterprises for the production of cellulose, cast iron, asphalt chips;
• chemical laboratories.

Hydrogen sulfide is extremely toxic and hazardous to health. When a high dose is present in the atmosphere, one breath is enough to cause death.

Once in the body, the substance is oxidized and forms inorganic compounds. When inhaled, hydrogen sulfide paralyzes the olfactory nerves, and a person ceases to smell the gas, which has a fatal effect. This often leads to severe poisoning due to failure to promptly recognize and stop contact with the toxic source.

Upon penetration into the internal environment of the body, the mechanism of toxic action is aimed at damaging the nervous and hematopoietic systems, bone marrow.

The gas has a damaging effect on mucous membranes. Due to the destruction of hemoglobin, it leads to severe hypoxia (oxygen starvation). Such a systemic influence disrupts the functionality of all organs. The brain is the first to be affected by toxic poisoning.

In the hot season, the likelihood of a stronger effect of the gas on humans increases. This is due to the fact that the activity of the toxic compound when high temperatures increases, its volatility increases. The gas easily and easily penetrates the skin and mucous membranes of the respiratory tract.

The toxic mechanism of action starts already when the hydrogen sulfide content in the air is 0.06%. At a concentration of no more than 150 mg/l, mucous membranes are irritated. Quantitative indicators of 1.2-1.8 mg per liter of inhaled air cause death. The alcohol content in the body enhances the effect of the poison.

Signs of hydrogen sulfide poisoning

When inhaling air poisoned by harmful hydrogen sulfide compounds, a person begins to feel unwell, dizziness and pain in the temporal and occipital parts of the head. Nausea gradually increases. A metallic taste appears in the mouth.

Mild poisoning

A mild degree of poisoning is manifested by an irritating effect on the mucous membranes of the eyes and respiratory tract. There is a burning sensation of the conjunctiva, pain and pain in the eyeball. Severe lacrimation begins, which leads to maceration of the skin (softening). Fear develops sunlight. Under the influence of gas, the circular muscles around the eyes contract, the eyelids close intensely and swell. The sclera becomes red.

The nasal mucosa becomes inflamed and copious exudate is formed. The victim develops a runny nose. The throat is irritated, itchy and sore. Chest pain and cough appear. When listening, dry wheezing can be heard. A bronchospasm occurs reflexively.

Average degree of poisoning

Pain in the head intensifies, general weakness increases. Coordination of movements is impaired. The general condition of a person changes quickly, from excitement to fainting. The skin turns blue, the heart rate increases, and blood pressure drops.

Against the backdrop of a functionality failure internal organs there is an involuntary act of defecation in the form of loose stool and urinary incontinence. Body temperature rises rapidly. Due to damage to the respiratory system, inflammation of the bronchi and lungs develops.

Kidney filtration is impaired. Casts and protein are found in the urine.

Severe poisoning

In severe cases of hydrogen sulfide poisoning, the condition and life of the victim is at risk. The functioning of vital organs - heart, lungs, kidneys, brain, liver - is seriously impaired.

The person is in a coma. This is preceded by the following signs:

• apathy;
• loss in space and time;
• stunned;
• reduction of emotional manifestations;
• collapse.

Persistent encephalopathy develops - functional disruptions in the functioning of the nervous system due to insufficient blood supply to the brain. As a result of oxygen starvation, tinnitus, hearing loss, double vision, memory loss, hallucinations, delusions, and speech disorders appear. In severe cases, temporary loss of vision occurs.

While in a coma, the victim develops severe swelling of the internal organs, which leads to failure of the respiratory system and heart.

Fatal hydrogen sulfide poisoning

The apoplectic form of damage to the body develops suddenly and with lightning speed. The conditions for such poisoning are a gas content in the air of 1000 mg per m 3.

The person instantly loses consciousness. Damage to the nervous system causes epileptic spasms of skeletal muscles.

Death occurs as a result of paralysis of the respiratory center in the medulla oblongata. Sometimes the myocardium, the muscular lining of the heart, is paralyzed.

Subacute poisoning

At low concentrations of gas in the air, symptoms of poisoning appear gradually and are mild:

• headache;
• periodic increase in body temperature up to 37.5°C;
• chills;
• dyspeptic gastrointestinal disorders;
• salivation;
• loose stools that are dark green or black;
• fatigue, lethargy, decreased performance;
• sweating, long-lasting runny nose;
• drying of mucous membranes, painful swallowing;
• conjunctivitis;
• inflammation of the trachea and bronchi.

Chronic poisoning

This type of poisoning is possible in case of non-compliance with safety precautions in production using hydrogen sulfide, where there is a potential risk of toxic effects of the gas on humans.

Signs:

• chronic diseases of the eyes, upper respiratory system (rhinitis, laryngitis, pharyngitis, sinusitis);
• systematic disorders of the functionality of the gastrointestinal tract;
• vegetative-asthenic syndrome– weakness, loss of appetite, sleep disturbance, slow heartbeat, drop in blood pressure, polyneuritis.

Complications after hydrogen sulfide poisoning

If a person has suffered acute or subacute intoxication with poisonous gas, in this case adverse effects and complications from internal organs often develop.

The victim constantly has headaches. Sometimes there are fevers. More often, infectious and inflammatory diseases of the respiratory system are associated - bronchitis, pneumonia, edema of the lung parenchyma, and gas exchange dysfunction.

When the heart muscle is damaged, its dystrophy develops, which subsequently leads to myocardial infarction.

Organic lesions of the central nervous system, meningitis and encephalitis are observed.

In general, hydrogen sulfide has a negative effect on the human body, even at low concentrations. The gas is very toxic. The danger is created by the fact that a person quickly adapts to the pungent odor and ceases to feel it. Therefore, first aid to the victim is not always provided in a timely manner.