1.4. Toxic chemicals with general toxic effects
This group conventionally includes toxic substances that manifest their effects after entering the blood. They have a general cellular, general functional effect, directly and indirectly influencing metabolic processes at the tissue or cellular level. They can disrupt energy metabolism, cause oxygen deficiency in tissues (hydrocyanic acid, cyanides, nitriles, hydrogen sulfide), hemolysis of erythrocytes (arsenic hydrogen), inhibit the oxygenation of hemoglobin (carbon monoxide), uncoupling oxidation and phosphorylation (amino derivatives of aromatic carbons). Substances of this group damage the receptor apparatus of cells, the condition of their membranes and the activity of enzyme systems in intracellular structures. The effect of action in most cases develops instantly, rarely slowly, while the picture of acute poisoning is ambiguous and is determined by the mechanism of action.
Sinilnaya acid (cyanide) hydrogen) NS N . Hydrocyanic acid in a bound state is found in plants in the form of heteroglycosides; when some of them are consumed, HCN is released as a result of enzymatic hydrolysis of glycosides . Hydrocyanic acid was first synthesized in 1978. Swedish scientist K. Scheele. It was used as a combat agent in 1916. Hydrocyanic acid, like cyanogen chloride, is in service with a number of armies. Widely used in the chemical industry, production of organic glass, plastics, and agriculture (fumigant). HCN is a highly volatile liquid with the odor of bitter almonds. It has high penetrating ability, is sorbed by various porous materials, and is poorly absorbed by activated carbon. When mixed with air it explodes.
Hydrocyanic acid is a powerful, fast-acting poison that blocks tissue respiration by almost 90-95%, as a result of which tissues lose the ability to absorb oxygen supplied by the blood. As a result of tissue hypoxia, the activity of the central nervous system, respiratory, cardiovascular systems, and metabolism is disrupted. Venous blood acquires a bright scarlet color and contains a lot of oxygen, like arterial blood, which occurs due to the addition of a cyanogen group to tissue oxidative enzymes, in particular to cytochrome oxidase (cytochrome a3).
Hearth unstable, fast-acting, most dangerous in winter.
The territory is being degassed using one of the following methods to neutralize hydrocyanic acid.
1) Hypochlorites are used:
2HCN + Ca (OCl)2 Ca (CNO)2 + CaCl2 + 2H2O
To neutralize 1 part of hydrocyanic acid using this method, 4.5 parts of calcium hypochlorite or about 45 parts of a 10% aqueous solution of hypochlorite are required.
2) Hydrocyanic acid enters well into complexation reactions with iron and copper sulfates in an alkaline medium to form hexocyanates:
2СN + Fe Fe(СN)2; 4NaCN + Fe(CN)2 Na4
3СN + Fe Fe(СN)3; 3NaCN + Fe(CN)3 Na3
Ferrous sulfate and sodium hydroxide are taken in a 1:1 ratio with hydrocyanic acid.
3) To degas hydrocyanic acid in rooms where deratization work was carried out, you can use ventilation or spraying of formalin, formaldehyde, upon interaction with which glycolic acid nitrile is formed: HCN + H2C=O → HO-CH2-C=N
IN In this case, to degas 1 part of hydrocyanic acid, 3 parts of formalin are required (40% formaldehyde solution in water).
PPE: gas masks.
Sanitary processing usually not carried out. Hydrocyanic acid vapors are well absorbed by materials, so they are dangerous and must be destroyed or degassed in compliance with safety precautions; it is recommended to quickly remove outer clothing (desorption).
Paths penetration inhalation, at very high concentrations of vapors in the air enters through damaged skin.
Signs of damage: at high concentrations, a fulminant (apoplectic) form of damage is characteristic, developing within a few seconds or minutes: sudden dizziness, tachycardia, shortness of breath, involuntary scream due to spasm of the muscles of the glottis, convulsions, respiratory arrest, cardiac arrest.
At low concentrations, the course is slow, clinical manifestations are less pronounced: minor local irritation of the mucous membranes of the upper respiratory tract and eyes, bitterness in the mouth, salivation, nausea, muscle weakness, shortness of breath, a feeling of fear. In favorable cases, when the victim immediately leaves the contaminated area, these symptoms quickly disappear.
With prolonged exposure, painful shortness of breath occurs, consciousness is depressed, the skin and mucous membranes are pink in color, and the pupils are dilated. Clonic-tonic, tetanic convulsions with jaw lockjaw, unconsciousness, rare, labored breathing, bradycardia, arrhythmia. In favorable cases, the symptoms of poisoning disappear after a few hours.
In an unfavorable case, a paralytic stage occurs, characterized by loss of reflexes, muscle relaxation, involuntary defecation and urination; the pressure drops. The pulse is frequent, weak, arrhythmic. The heart “experiences breathing” for several minutes. The pink color of the skin and mucous membranes is characteristic (preserved even posthumously).
Antidote therapy for damage caused by hydrocyanic acid and cyanides
According to the mechanism of antidote action, antidotes are divided into methemoglobin-forming substances, carbohydrates and substances containing sulfur.
TOmethemoglobin-forming antidotes include: amyl nitrite, sodium nitrite, 4-dimethylaminophenol, anticyanin and methylene blue. These compounds (nitrites and phenolic derivatives) are oxidizing agents and, when they enter the blood, cause the conversion of oxyhemoglobin into methemoglobin. The latter, unlike oxyhemoglobin, contains ferric iron, so it is able to compete with cytochrome oxidase for cyanide and actively combines with the cyano group to form methemoglobin cyanide: Hb → MtHb; MtHb (Fe +++) + CN - ↔ CN(Fe +++) MtHb
In this case, hydrocyanic acid (cyanides) gradually passes from the tissues into the blood and binds to methemoglobin. Cytochrome oxidase (cytochrome a3) is released, and tissue respiration is resumed, the condition of the affected person immediately improves. However, cyanmethemoglobin is an unstable compound, it disintegrates over time, the cyanogen group can again enter the tissue, again bind cytochrome a3, and again the condition of the affected person will worsen, therefore, it is necessary to introduce other antidotes. In addition, it should be borne in mind that methemoglobin cannot serve oxygen carrier, therefore, for therapeutic purposes, its content in the blood is allowed to be no more than 30% in order to avoid the development of hemic hypoxia. In addition, nitro compounds can have a sharp vasodilator effect; in case of overdose, they can cause nitrite collapse, so sodium nitrite is not recommended for use in field conditions.
Amyl nitrite - intended for first aid. Available in ampoules with a braid of 1 ml, taken by inhalation: crush the thin end of the ampoule with light pressure and bring it to the nose of the affected person; in a poisoned atmosphere, the ampoule in a gauze wrapper with a crushed end should be placed under a gas mask for inhalation. Amyl nitrite has a short-term effect, so after 10-12 minutes it is given again (up to 3-5 times).
Antician - accepted in our country as a standard antidote for hydrocyanic acid and cyanide. Available in ampoules of 1 ml of 20% solution. The therapeutic effectiveness of the drug is associated with its ability to form methemoglobin and activate the biochemical processes of tissue respiration in organs and systems. It improves blood supply to the brain, has a beneficial effect on cardiac activity, and increases the body's resistance to hypoxia.
In field conditions, anthicyanin is administered intramuscularly (1 ml of 20% solution per 60 kg of body weight). In case of severe poisoning, repeated administration of anticyanin is allowed intravenously after 30 minutes, 0.75 ml of 20% solution or intramuscularly, 1 ml 1 hour after the first administration. For intravenous administration, the drug is diluted in 10 ml of 25-40% glucose solution or 0.85% NaCl solution. Sodium thiosulfate potentiates the action of anthicyanin.
Sodium nitrite is a more powerful methemoglobin former. Aqueous solutions of the drug are prepared extempore, since they are not stable during storage. A freshly prepared sterile 1% solution is administered intravenously in a dose of 10-20 ml slowly (over 3-5 minutes), avoiding a decrease in maximum blood pressure of more than 90 mm Hg. and the development of nitrite shock.
4-dimethylaminophenol hydrochloride (4- DAMF) is accepted in a number of countries as a cyanide antidote. Available in ampoules in the form of a 15% solution, administered intravenously at the rate of 3-4 ml/kg of the affected person’s weight in a mixture with glucose solution. In this case, up to 30% of methemoglobin is formed in the blood. It does not cause vasodilation and collapse, unlike the previous drug.
Methylene blue (50 ml of the drug in the form of 1% solution in 25% glucose solution, the so-called chromosmon ) accentuates hydrogen and activates tissue respiration, but is currently not recommended as a cyanide antidote for a number of reasons: lack of effectiveness, the possibility of side effects, and the ability to cause hemolysis.
Antidotes that bind the cyano group.
Thiosulfate sodium (sodium hyposulfite) - considered the most effective, it is available in ampoules of 20-50 or 30% solution, administered intravenously in a dose of 20-50 ml. In the body, a sulfur atom is split off from thiosulfate, which combines with cyanide to form a non-toxic, persistent substance, thiocyanate. Moreover, this reaction occurs quickly (in the liver, kidneys and brain) in the presence of the enzyme rhodanase:
rhodanase Na2S2O3 + НCN → NaCNS + NaHSО 3
Glucose, Due to the content of the aldehyde group, it combines with cyanides (hydrocyanic acid) to form a low-toxic hydroxynitrile - cyanohydrin.10-20 ml of 20-40% solution is administered intravenously alone or in a mixture with anthicyanin. In addition, it has a beneficial effect on breathing, heart function and increases diuresis.
Vitamin B12 is also recommended as a cyanide antidote. Two varieties of this vitamin are known: hydroxocobalamin (an OH group is linked to the cobalt atom) and cyanocobalamin, where A cyano group is already bound to the cobalt atom; only hydroxocobalamin (as an auxiliary agent) can serve as an antidote, due to the ability of the cyano group to form complex compounds with heavy metals (iron, gold, cobalt, etc.).
Dicobalt salt ethyl diamine tetraacetate (Co 2 EDTA) is also an active antidote to cyanide, belonging to the class of complexones that easily binds the cyano group:
Co2EDTA + 2CN → (CN)2Co2 EDTA
Co2 EDTA is administered intravenously at 10-20 or 15% solution, very slowly, as it can cause hypertension, suffocation, edema and etc.
Thus, the following treatment regimen for lesions with hydrocyanic acid and cyanides has been adopted: inhalation of amyl nitrite, as the simplest and most accessible remedy under all conditions; administration of anticyanin intramuscularly or intravenously; intravenous administration of sodium thiosulfate and glucose.
There is evidence of a beneficial therapeutic effect unithiol , which activates the enzyme rhodonase and accelerates the detoxification process.
First and first aid: should be provided immediately, since this is a poisonous substance with a rapid lethal effect:
in the hearth: put on a gas mask, give an inhalation antidote (crush the upper end of the ampoule of amyl nitrite and place it under the gas mask as the victim exhales), immediately remove the victim from the affected area;
outside the hearth:
Repeatedly inhale the inhalation antidote amyl nitrite (up to 3-5 times with an interval of 10-12 minutes);
Inject 1 ml of 20% anticyanin solution intramuscularly;
Remove contaminated clothing, remove the gas mask, remove clothing that restricts breathing, protect from cooling;
If there is a wound or abrasion on the skin, rinse thoroughly with water and soapy water;
In case of respiratory failure - artificial respiration;
When cardiac activity is weakened - 1-2 ml cordiamine subcutaneously;
Immediately evacuate to a medical facility.
peace, warmth; antidote therapy (repeat at intervals of 1-2 hours); repeated inhalation of amyl nitrite; IV or IM anticyanin with glucose; for IV administration - 1% sodium nitrite solution, 30% sodium thiosulfate solution. At reduced pressure - 15% dicobalt salt EDTA; 40% glucose solution and 5% ascorbic acid solution; for bradycardia - 0.1% atropine sulfate, for cardiac dysfunction - corglycone with saline solution, cordiamine; for ongoing convulsions - seduxen or phenozepam; vitamin B2, cytochrome C; according to indications - oxygen therapy, oxygen barotherapy, administration of cititon or lobeline.
Cyanides, halogenyanides . Potentially dangerous cyanides and their halogen derivatives are potassium cyanide, sodium cyanide, cyanide (mixture of sodium cyanide up to 47% and calcium oxide 50%), cyanogen, cyanamide and cyanogen chloride(ClCN), which is used as a combat agent. Many cyanides in high humidity under the influence of atmospheric carbon dioxide, hydrocyanic acid is easily released . If the latter accumulates in a room, an explosion may occur.
Hearth unstable, local, especially dangerous in the cold season.
Entry routes: inhalation and oral.
Signs of defeat similar to those caused by hydrocyanic acid poisoning.
Chlorcyanide(is a poison of tissue oxidases - cytochrome oxidase), has a pronounced irritant effect on the mucous membranes of the eyes and respiratory tract: burning, pain in the eyes, nasopharynx, nose and chest, lacrimation, conjunctivitis, sneezing, coughing, which quickly disappear, in more severe cases - the picture is complemented by shortness of breath, pulmonary edema, ulceration of the cornea; at high concentrations, death occurs due to symptoms of convulsions and paralysis of the respiratory center.
Emergency medical care the same as for poisoning with hydrocyanic acid and irritating substances. In case of poisoning with potassium cyanide or sodium, it is necessary to lavage the stomach using a probe with a solution of potassium permanganate diluted 1:1000 or a 5% solution of sodium thiosulfate, or a 2% solution of baking soda, and a salt laxative is prescribed. Drink plenty of fluids. In case of defeat cyanogen chloride it is necessary to rinse the eyes and rinse the nasopharynx with 2% sodium bicarbonate solution and use painkillers.
Hydrogen sulfide (H2 S ) widely used in the chemical industry. Gas, colorless, with the smell of rotten eggs; at high concentrations the odor is not noticeable. Easily soluble in water (weak acid). It is flammable and forms an explosive mixture with air. Dangerous in combination with nitric oxide. May explode in containers.
Hearth unstable, fast-acting. The gas cloud spreads and accumulates in low places. Particularly dangerous in confined spaces.
PPE: gas masks (at high concentrations - an insulating gas mask), protective suit - against open flame.
Degassing of the territory: when hydrogen sulfide is released into the atmosphere from a liquefied state, it is necessary to use sprayed water and isolate the area within a radius of 100 m, in case of fire - up to 800 m. The spill site is filled with caustic solution and milk of lime.
Routes of penetration: inhalation and through the skin. In the body it is quickly neutralized in the liver. It is excreted in the urine in the form of sulfate, part of the unchanged hydrogen sulfide is excreted by the lungs.
Hydrogen sulfide is a highly toxic, fast-acting nerve poison. It affects respiratory enzyme tissues (cytochrome oxidase), which causes tissue hypoxia. Has a local irritant effect.
Signs of damage: lacrimation, cough, runny nose; in more severe cases, burning and pain in the pharynx when swallowing, conjunctivitis, blepharospasm, bronchitis with mucous sputum, toxic pulmonary edema, bronchopneumonia; dizziness, weakness, vomiting, tachycardia, decreased blood pressure. When exposed to high concentrations - loss of consciousness, convulsions due to hypoxia, coma. At very high concentrations - a fulminant form of damage: respiratory paralysis, complications of the central nervous system, lungs, and heart are possible.
There is no antidote. Methemoglobin formers (amyl nitrite, methylene blue, chromosmon) are indicated.
First and first aid:
in the hearth: put on a gas mask, take it out into fresh air, ensure rest, inhale amyl nitrite.
outside the hearth:
Provide peace and warmth;
Rinse eyes with water, 2% solution of baking soda, protect eyes from light, drip 2% solution of novocaine;
Rinse your face and exposed skin thoroughly with water, gargle with a 2% solution of baking soda;
Evacuate lying or sitting.
Emergency medical care at the hospital stage:
alkaline inhalations, inhalations of hydrocortisone, antibiotics, aminophylline, ephedrine; for breathing problems - oxygen inhalation; methylene blue 20 ml 1% solution with glucose 25% 20-30 ml (chromosmon); means for the treatment of toxic pulmonary edema, with severe agitation - Relanium, GHB, antibiotics, vitamins B and C, cytochrome C, sulfonamides.
Oxide carbon (carbon monoxide) gas, CO) is a product of incomplete combustion of organic substances, a highly toxic gas, colorless, odorless and tasteless, lighter than air. The source of poisoning can be exhaust gases from internal combustion engines, powder and explosive gases. Mass poisonings can occur in fires and nuclear hotspots both in peacetime and in wartime. Explosive.
Hearth unstable, fast-acting. The gas is very dangerous in confined, poorly ventilated places and is infectious. upper atmosphere .
Carbon monoxide is a hemic poison. The mechanism of action is that, penetrating into the blood by inhalation, CO combines with the ferrous iron of oxyhemoglobin or reduced hemoglobin to form carboxyhemoglobin:
CO+HbO2 HbCO+O2
CO+Hb HbCO
The affinity of CO for hemoglobin is 250-300 times greater than that of oxygen, while the oxygen content decreases sharply, a significant proportion of hemoglobin ceases to participate in oxygen transport, and anoxemia (hemic hypoxia) develops. When the intake of CO into the body ceases, the dissociation of carboxyhemoglobin and the release of CO through the lungs begin. The toxic effect of CO is also explained by the interaction with heme enzymes (tissue hypoxia is added) - cytochrome az, cytochrome oxidase, tissue iron-containing biochemical structures - myoglobin and other enzymes, as well as a direct toxic effect on cells and tissues, ATPase is inhibited, and the ATP content in tissues decreases.
PPE: a gas mask with a hopcalite cartridge, an industrial filter gas mask of the CO brand or an insulating gas mask.
Sanitation are not carried out.
Entry routes V body and inhalation excretion.
Signs of damage: in high concentrations, when the content of carboxyhemoglobin in the blood is 75% or more, lightning-fast complete loss of consciousness, convulsions and respiratory paralysis, cadaveric rigidity (frozen postures in the dead) occur. At lower concentrations, a delayed form develops. It is customary to distinguish 3 degree of severity.
For mild degree (carboxyhemoglobin content in the blood 20-30%) - heaviness, pressure in the head, headache, dizziness, tinnitus, pulsation in the temples, nausea, drowsiness, lethargy, breathing and pulse are increased, shortness of breath during physical exertion.
With average degree of severity (carboxyhemoglobin content in the blood 35-50%) - increasing weakness, shortness of breath, palpitations, loss of coordination, convulsions, confusion, light red facial skin, less often cyanotic,
For severe(carboxyhemoglobin content in blood 50-60%) loss of consciousness (hours, days), muscle relaxation, facial skin, pink mucous membranes, involuntary loss of night and feces, shallow, arrhythmic breathing, temperature 38-40°C, coma.
Atypical forms of poisoning are also observed: syncope and euphoria. Syncope is characterized by a decrease in blood pressure, a prolonged coma (hours), pale skin of the face and mucous membranes - “white asphyxia”; euphoric is characterized by pronounced excitement, mental disorders (hallucinations, delusions, unmotivated actions). Then comes loss of consciousness, respiratory and cardiac dysfunction. Acute poisoning is accompanied by damage to various body systems, primarily the central nervous system (the cerebral cortex, which is most sensitive to hypoxia and CO, is especially affected).
A specific antagonist of CO in the body is oxygen, which competitively prevents it from joining hemoglobin and displaces it from hemoglobin, thus accelerating. dissociation of carboxyhemoglobin and removal of CO from the body through the lungs.
First and first aid:
in the hearth: put on a special one gas mask with a hopcalite cartridge (when CO hits the surface of a hopcalite catalyst consisting of manganese dioxide - 60% and copper oxide - 40%, it is oxidized to CO2, and the catalyst is reduced: CO + MnO2 → CO2 + MnO, then the catalyst again oxidizes and returns to its original state:
MnO2 + O2 → 2MnO2.) or an insulating gas mask, since a regular gas mask does not retain CO; Immediately remove the victim from the affected area (in the absence of a gas mask, the primary action!)
outside the hearth: remove the gas mask, remove clothing that restricts movement; provide rest, warmth, prevention of tongue retraction and aspiration of vomit; oxygen inhalation; according to indications - artificial respiration, indirect cardiac massage; administration of 1-2 ml of cordiamine subcutaneously, sulfocamphocaine, caffeine, evacuation to a medical facility (oxygen therapy along the way).
Emergency medical care at the hospital stage
abundant oxygen inhalations (hyperbaric oxygenation) on the first day - again after 10-12 hours; if breathing stops - mechanical ventilation; for collapse - mezatone, ephedrine, for severe agitation - GHB, barbamyl 10% solution, relanium, 25% solution of magnesium sulfate; for convulsions 0,5% diazepam solution, sodium hydroxybutyrate; for prolonged coma, cerebral edema: urea, mannitol, hypertonic solutions of glucose, calcium chloride or gluconate, nicotinic acid, aminophylline, rheopolyglucin, trental; hypothermia of the head (ice); plasma, albumin solution; for hyperthermia, lytic mixture, 50% analgin solution; CVS tonics for pneumonia - antibiotics, sulfonamides, ultraviolet irradiation of blood; vitamin therapy, ascorbic acid, cytochrome C, cocarboxylase; means of eliminating acidosis.
Arsenic hydrogen (arsine) - colorless gas, under normal conditions with an unpleasant garlic odor. Does not dissolve well in water.
Hearth unstable, slow action. The danger of injury to people in places of stagnation, especially in the autumn-winter period, increases. If high concentrations of arsenic hydrogen enter water sources, contamination of the lower layers of water may occur. An infected gas cloud accumulates in low places.
PPE: gas masks.
Sanitation are not carried out.
Routes of penetration: inhalation, without causing discomfort (contact with the poison is invisible). Well adsorbed by hair and skin. It is excreted in urine and feces in the form of complex compounds.
Arsenous hydrogen is a poison with a predominantly resorptive effect. latent period . Being a highly toxic compound, it affects primarily the blood, leading to hemolysis of red blood cells. The hemolytic effect depends on the ability of arsenic to cause pathological oxidation, as a result of which peroxide compounds accumulate. As a result of the hemolytic effect, progressive hemolytic anemia, jaundice, hepatorenal syndrome, vascular hypotension, and damage to the central and peripheral nervous system develop.
Signs of damage: There are no complaints at the time of poisoning. Characteristic is the slow rate of development of acute poisoning. After latent period (from 2 to 24 hours depending on the concentration, exposure and individual sensitivity) dizziness, severe headache, weakness, anxiety, chills, fever, nausea, vomiting, and lower back pain appear. The temperature rises. Urine appears pink or red. The liver is affected and enlarged (toxic hepatopathy), spleen, renal failure develops (decreased diuresis), jaundice, diarrhea, motor agitation up to convulsions. The mortality rate is high, on average 20-30%.
First and first aid:
in the hearth: put on a special industrial gas mask or a cotton gauze bandage moistened with water, remove (remove) from the fireplace, regardless of the patient’s complaints;
outside the hearth: remove the gas mask, free the affected person from clothing that restricts breathing, provide absolute rest, heat, subcutaneous or intramuscular administration of the antidote - mecaptide 1 ml of 40% oil solution, unithiol 5 ml of 5% solution; evacuation to a medical facility.
Emergency medical care at the hospital stage:
Absolute peace, warmth; antidote therapy - mecaptide and unithiol according to the scheme; with hemoglobinuria 5% glucose solution with 2% novocaine solution, a means of alkalizing blood, treating toxic hepatopathy; for hemolytic anemia - red blood cells, iron-containing preparations (ferrum Lek, etc.); antibiotics; cardiovascular drugs; hematopoietic stimulants, vitamins.
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Substances used and formed in technological processes at enterprises, due to improper organization of work and non-compliance with certain preventive measures, which have a harmful effect on the health of workers, leading to acute or chronic poisoning and occupational diseases, are called harmful substances(industrial poisons).
Poisoning that workers can get can be acute or chronic.
Harmful substances can enter the human body through the respiratory system (vapors, gases, dust), skin (liquid, oily, solid substances), and the gastrointestinal tract (liquid, solid, and gases). Most often, harmful substances enter the human body through the respiratory system and quickly penetrate to vital human centers.
In addition to the general effect on the human body, harmful substances can also have a local effect. This is how acids, alkalis, some salts and gases (chlorine, sulfur dioxide, hydrogen chloride, etc.) act. Chemicals can cause three degrees of burns.
Poisons may enter the gastrointestinal tract if personal hygiene rules are not followed. Toxic substances, cyanides can be absorbed already in the oral cavity, entering the blood.
Classification of toxic substances
Based on their toxic (harmful) effect on the human body, chemical substances are divided into general toxic, irritating, sensitizing, carcinogenic, mutagenic, and affecting reproductive function.
Generally toxic chemicals(hydrocarbons, hydrogen sulfide, hydrocyanic acid, tetraethyl lead) cause nervous system disorders, muscle cramps, affect hematopoietic organs, and interact with blood hemoglobin.
Irritants(chlorine, ammonia, nitric oxide, phosgene, sulfur dioxide) affect the mucous membranes and respiratory tract.
Sensitizing substances(antibiotics, nickel compounds, formaldehyde, dust, etc.) increase the body’s sensitivity to chemicals, and in industrial conditions lead to allergic diseases.
Carcinogens(benzopyrene, asbestos, nickel and its compounds, chromium oxides) cause the development of all types of cancer.
Chemical substances, affecting human reproductive function (boric acid, ammonia, many chemicals in large quantities), cause congenital malformations and deviations from normal development in the offspring, affect the intrauterine and postnatal development of the offspring.
Mutagenic substances(lead and mercury compounds) affect non-reproductive (somatic) cells that are part of all human organs and tissues, as well as germ cells. Mutagenic substances cause changes (mutations) in the genotype of a person in contact with these substances. The number of mutations increases with the dose, and once a mutation has occurred, it is stable and is passed on from generation to generation unchanged. Such chemically induced mutations are non-directional. Their load joins the general load of spontaneous and previously accumulated mutations. Genetic effects from mutagenic factors are delayed and long-lasting. When exposed to germ cells, the mutagenic effect affects subsequent generations, sometimes in very distant periods.
Rice. 1. Classification of harmful substances
The last three types of harmful substances (mutagenic, carcinogenic and affecting reproductive ability) are characterized by long-term consequences of their influence on the body. Their effect manifests itself not during the period of exposure and not immediately after its end, but in distant periods, years and even decades later.
The above classification of harmful substances by the nature of their impact does not take into account a large group of substances - aerosols (dust) that do not have pronounced toxicity. These substances are characterized fibrogenic effect effects on the body. Aerosols of coal, coke, soot, diamonds, dust of animal and plant origin, silicate and silicon-containing dust, metal aerosols, when entering the respiratory system, cause damage to the mucous membrane of the upper respiratory tract and, when retained in the lungs, cause inflammation (fibrosis) of the lung tissue. Occupational diseases associated with exposure to aerosols are pneumoconiosis.
Pneumoconiosis is classified into:
- silicosis - develops under the influence of free silicon dioxide dust;
- silicates - develop under the influence of aerosols of silicic acid salts;
- types of silicosis: asbestosis (asbestos dust), cementosis (cement dust), talcosis (talc dust);
- mstalloconiosis - develops when inhaling metal dust, such as beryllium dust (berylliosis);
- carboconiosis, for example anthranosis, which occurs when inhaling coal dust.
The result of human inhalation of dust is pneumosclerosis, chronic dust bronchitis, pneumonia, tuberculosis, and lung cancer.
The presence of a fibrogenic effect in aerosols does not exclude their general toxic effects. Toxic dusts include aerosols of DDT, lead, beryllium, arsenic, etc. When they enter the respiratory system, in addition to changes in the upper respiratory tract and lungs, acute and chronic poisoning develops.
In production, work is usually carried out with several chemicals. In this case, the employee may be exposed to negative factors of a different nature (physical - noise, vibration, electromagnetic and ionizing radiation). This creates the effect combined(with the simultaneous action of negative factors of different nature) or combined(with the simultaneous action of several chemicals) the effects of chemicals.
Combined action- this is the simultaneous or sequential effect on the body of several substances through the same route of entry into the body. There are several types of combined action depending on the toxicity effects:
- summation (additive action, additivity) - the total effect of the mixture is equal to the sum of the effects of the components included in the mixture. Summation is typical for substances of unidirectional action, when substances have the same effect on the same body systems (for example, mixtures of hydrocarbons);
- potentiation (synergistic effect, synergism) - substances act in such a way that one substance enhances the effect of another. The synergistic effect is more additive. For example, nickel increases its toxicity in the presence of cuprous waste by 10 times, alcohol significantly increases the risk of aniline poisoning;
- antagonism (antagonistic action) - the effect is less than additive. One substance weakens the effect of another. For example, eserine significantly reduces the effect of antropine and is its antidote;
- independence (independent action) - the effect does not differ from the isolated action of each of the substances. Independence is characteristic of substances with multidirectional effects, when substances have different effects on the body and affect different organs. For example, benzene and irritating gases, mixtures of combustion products and dust act independently.
Along with the combined effect of substances, it is necessary to highlight complex action. With complex action, harmful substances enter the body simultaneously, but in different ways (through the respiratory organs and skin, respiratory organs and gastrointestinal tract, etc.).
Maximum permissible concentration of harmful substances
The harmful biological effects of chemicals begin at a certain threshold concentration. To quantify the harmful effects of a chemical on humans, indicators characterizing the degree of its toxicity are used. These indicators include:
- average lethal concentration of a substance in the air (LC50);
- average lethal dose (LD50);
- average lethal dose when applied to the skin (LDK50);
- acute action threshold (APT);
- threshold of chronic action (TCT);
- acute action zone (AZZ);
- zone of chronic action (ZAD);
- maximum permissible concentration.
Hygienic regulation, i.e. limiting the content of harmful substances to maximum permissible concentrations (MACs), is used to limit the adverse effects of harmful substances. Due to the fact that the requirement for the complete absence of industrial poisons in the breathing zone of workers is often impossible, hygienic regulation of the content of harmful substances in the air of the working area (GN 2.2.5.1313-03 “Maximum permissible concentrations of harmful substances in the air of the working area”, GN) acquires particular importance 2.2.5.1314-03 “Indicative safe exposure levels”).
Harmful substance in the air of a working area (HSA) - a concentration of a substance that, during daily (except weekends) work for 8 hours or another duration, but not more than 40 hours a week during the entire work experience, cannot cause diseases or abnormalities health, detected by modern research methods in the process of work or long-term life spans of the present and subsequent generations.
MPCZ, as a rule, is set at a level 2-3 times lower than the threshold for chronic action. When the specific nature of the action of a substance is revealed (mutagenic, carcinogenic, sensitizing), the maximum permissible limit is reduced by 10 times or more.
In the classification according to the toxic (harmful) effect on the human body, chemical substances are divided into general toxic, irritating, sensitizing, carcinogenic, mutagenic, and affecting reproductive function.
Generally toxic chemicals(hydrocarbons, hydrogen sulfide, hydrocyanic acid, tetraethyl lead) cause nervous system disorders, muscle cramps, affect hematopoietic organs, and interact with blood hemoglobin.
Irritants(chlorine, ammonia, nitric oxide, phosgene, sulfur dioxide) affect the mucous membranes and respiratory tract.
Sensitizing substances(antibiotics, nickel compounds, formaldehyde, dust, etc.) increase the body’s sensitivity to chemicals, and in industrial conditions lead to allergic diseases.
Carcinogens(benzopyrene, asbestos, nickel and its compounds, chromium oxides) cause the development of all types of cancer.
Chemical substances, affecting human reproductive function (boric acid, ammonia, many chemicals in large quantities), cause congenital malformations and deviations from normal development in the offspring, affect the intrauterine and postnatal development of the offspring.
Mutagenic substances(lead and mercury compounds) affect non-reproductive (somatic) cells that are part of all human organs and tissues, as well as germ cells. Mutagenic substances cause changes (mutations) in the genotype of a person in contact with these substances. The number of mutations increases with the dose, and once a mutation has occurred, it is stable and is passed on from generation to generation unchanged. Such chemically induced mutations are non-directional. Their load joins the general load of spontaneous and previously accumulated mutations. Genetic effects from mutagenic factors are delayed and long-lasting. When exposed to germ cells, the mutagenic effect affects subsequent generations, sometimes in very distant periods.
The harmful biological effects of chemicals begin at a certain threshold concentration. To quantify the harmful effects of a chemical on humans, indicators characterizing the degree of its toxicity are used. These indicators include the average lethal concentration of a substance in the air (LC50); average lethal dose (LD50); average lethal dose when applied to the skin (LDK50); acute action threshold (LimО.Д); threshold of chronic action (LimХ.Д); zone of acute action (ZО.Д); zone of chronic action (Z Х.Д), maximum permissible concentration.
Hygienic regulation, i.e. limiting the content of harmful substances in the air of the working area to maximum permissible concentrations (MPC), is used to limit the adverse effects of harmful substances. Due to the fact that the requirement for the complete absence of industrial poisons in the breathing zone of workers is often impossible, hygienic regulation of the content of harmful substances in the air of the working area (GN 2.2.5.1313-03 “Maximum permissible concentrations of harmful substances in the air of the working area”, GN) acquires particular importance 2.2.5.1314-03 “Indicative safe exposure levels”).
Maximum permissible concentration of a harmful substance in the air of a working area (MPCL) - a concentration of a substance that, during daily (except for weekends) work for 8 hours or another duration, but not more than 40 hours a week during the entire work experience, cannot cause illness or deviations in health status detected by modern research methods in the process of work or long-term life spans of the present and subsequent generations.
MPCZ is usually set at a level 2–3 times lower than the threshold for chronic action. When the specific nature of the action of a substance is revealed (mutagenic, carcinogenic, sensitizing), the maximum permissible limit is reduced by 10 times or more.
Industrial poison- a harmful chemical substance to which a person may be exposed during industrial activities.
Industrial poisons include a large group of chemicals and compounds that are found in production in the form of raw materials, intermediate or finished products.
By the nature of the effect on the body substances are divided into:
- - general toxic- causing poisoning of the entire body or affecting individual systems (central nervous system, hematopoietic system), as well as causing pathological changes in the liver and kidneys (carbon monoxide, lead, mercury, benzene);
- - annoying- causing irritation of the mucous membranes of the respiratory tract, eyes, lungs, skin (chlorine, ammonia, sulfur and nitrogen oxides, ozone);
- - sensitizing- acting as allergens (formaldehyde, solvents);
- - mutagenic- leading to a violation of the genetic code, changes in hereditary information (lead, manganese, radioactive isotopes);
- - carcinogenic- causing malignant neoplasms (aromatic hydrocarbons, chromium, nickel, asbestos);
- - influencing reproductive function (mercury, lead, styrene).
Mutagenic, carcinogenic, effects on reproductive function, as well as acceleration of aging, are considered to be long-term consequences of the influence of chemical compounds on the body. This is a specific action that manifests itself years and even decades later.
This classification does not take into account the aggregate state of substances, while for a large group of aerosols that do not have pronounced toxicity, it is necessary to distinguish fibrogenic effect effects on the body. These include aerosols of coke, diamonds, dust of animal and plant origin, and silicate-containing dust. Once in the respiratory system, substances of this group damage the mucous membrane of the upper respiratory tract, and when retained in the lungs, they lead to the development of connective tissue in the air exchange zone and scarring (fibrosis) of the lungs. The presence of a fibrogenic effect does not exclude the general toxic effects of aerosols.
The effect of poison on tissue is accompanied by various changes. The action of the poison is called local, if changes are observed at the point of contact of the poison with the body, without a noticeable general reaction of the latter. The local effect of the poison is often short-lived and can be considered as the initial stage of the general process. When absorbed (resorption), toxic substances in toxic doses exhibit general action.
Local(irritant, cauterizing) effect on the skin and mucous membranes is exerted by many substances of various chemical structures - caustic gases and vapors (for example, chlorine, bromine, iodine, ammonia), caustic acids and alkalis, a number of organic substances (acids - acetic, oxalic, phenols , aldehydes).
The effect of caustic poisons is not limited to local damage; Depending on their nature, concentration, duration of exposure and place of application in the body, functional disorders arise, varying in clinical manifestation, intensity and outcome. Caustic gases and vapors cause severe irritation of the mucous membranes of the upper respiratory tract, and if these substances penetrate into the lungs, severe lesions (edema) develop in them.
General action poisons largely depends on the chemical structure of a particular substance.
Toxic substances are any chemical compounds (poisons, drugs) that harm the human body. These compounds are in any state of aggregation - gas, liquid, solid substance. Their effect on the body can be local or general, and signs of damage appear immediately or remotely (after several weeks, months, years).
Any toxic compounds that appeared in the geosphere as a result of human activity are called anthropogenic toxic substances.
Classification of toxic compounds
The variety of poisons of natural or industrial origin creates the need to divide them into groups. This has practical significance - adequate first aid for poisoning with toxic substances.
When exposed to toxic substances, the physiological functioning of the body is disrupted. In some cases, this phenomenon is persistent - occupational poisoning. According to their course, they are acute (symptoms appear immediately) and chronic - systematic poisoning in small doses over a long time.
Physiological classification of toxic substances:
- Nerve agents – sarin, VX, tabun, soman. These are the most highly toxic substances that are currently prohibited for production and use. Signs of poisoning are decreased visual acuity, lacrimation, constriction of the pupil, chest pain, frequent heartbeats. Breathing suddenly becomes difficult, shortness of breath appears, then bronchospasm occurs. In severe cases, convulsions appear in the first minutes, and death occurs from paralysis of the respiratory muscles.
- Blisters – mustard gas, lewisite. They enter the body upon contact with the skin, causing inflammation and swelling. The substances have a wide range of effects. A distinctive feature is the latent period before the first signs of poisoning appear, at least 4 hours. The first symptoms are malaise and increased body temperature. Then skin lesions appear - redness, abscesses, blisters, rashes, burns. Once in the blood, toxic substances affect the nervous system and cause general poisoning of the body.
- Generally toxic - hydrocyanic acid, carbon monoxide, cyanide compounds. They disrupt the functioning of the brain, heart, blood vessels, and lungs. Symptoms: dizziness, nausea, irregular heart rhythms, chest pain similar to a heart attack, shortness of breath. In severe cases - convulsions, respiratory paralysis, cardiac arrest.
- Asphyxiants - phosgene, diphosgene. The mechanism of action is damage to the respiratory system. First, toxic inflammation of the mucous membrane of the upper respiratory tract occurs, then toxic bronchitis and pneumonia develop. In severe cases, swelling and burns of the lungs. Symptoms of severe intoxication are temperature 39° and above, lack of air. Then blood pressure drops, pulse quickens, and collapse develops. Death occurs from pulmonary edema or complications - abscess, gangrene, bacterial pneumonia.
- Irritating chemicals – adamsite, chloropicrin, chloroacetophenone, diphenylchlorarsine. When breathing, the poison gets onto the mucous membranes of the eyes, nose, and larynx, is quickly absorbed into the blood and has an irritating effect on the nerve endings. A distinctive feature is that the person experiences severe pain. Symptoms are burning pain in the nose, throat, eyes, chest. Severe lacrimation, runny nose, shortness of breath, sneezing, cough. After half an hour the pain subsides. Complications – conjunctivitis, severe bronchitis, pulmonary edema.
- Psychochemical – BZ. The first symptoms of poisoning appear no later than 3 hours after the toxic substance enters the body - drowsiness, decreased performance. Then the heart rate increases, the skin and mucous membranes become dry. Later, retardation and speech impairment occur. The period of action of toxic substances lasts up to 4 days.
The same substance has different effects on the body. Microelements and vitamins contained in food products are beneficial for humans in moderate doses, but in large quantities they become toxic and pose a danger.
Classification by type of chemical elements:
- Carcinogenic – nickel, chromium, asbestos. They provoke the mechanisms of origin and development of cancer cells, accelerate the process of spread of metastases.
- Mutagenic – mercury, lead. The effect on the human body manifests itself in the form of chromosomal breakdowns and gene mutations. These microelements act slowly, accumulating in the body over the years.
- Sensitizing agents – drugs of chemical origin (antibiotics), dust, allergens. They weaken the immune system, increase sensitivity to external irritants, and lead to allergies.
- Chemical compounds – acids, alkalis. They cause chronic functional disorders in the body and affect the reproductive system.
Hazard classes of toxic substances
Characteristics of toxic substances are the toxic effect of harmful substances, the degree of damage to internal organs and systems, and other signs that divide poisons into hazard classes. This is a conditional value that is established in accordance with regulatory documents. Each toxic substance belongs to a specific hazard class.
Class 1 – extremely dangerous toxic substances. The list of these compounds includes:
- Plutonium is a heavy radioactive metal. It is most toxic if it comes into contact with the skin, and if inhaled or swallowed, leads to lung and stomach cancer. It tends to accumulate in the bone marrow, leading after many years to impaired hematopoiesis.
- Polonium is a soft radioactive metal. It is highly toxic and causes radiation damage to the skin. Instantly penetrates the body and irreversibly destroys tissue.
- Beryllium is a highly toxic solid metal. Possesses carcinogenic and irritant effects. Causes severe damage to the respiratory system.
Class 2 – highly dangerous toxic substances. Chemical elements and compounds:
- Arsenic is a brittle semimetal. If ingested, it causes acute pain, vomiting, diarrhea, and affects the central nervous system.
- Hydrogen fluoride is a strong-smelling, colorless gas. Causes burns and ulcerations of the mucous membranes of the eyes, mouth, and respiratory tract. In case of contact with skin, symptoms do not appear immediately. After a few hours, swelling, pain and general toxic effects on the body begin.
- Lead is a fusible metal. Affects the gastrointestinal tract, joints, bones. In high concentrations it leads to convulsions and loss of consciousness. In children, the brain is affected, resulting in mental retardation.
- Chlorine is a halogen, poisonous gas. Causes suffocation and lung burns.
Class 3 – moderately hazardous toxic substances. List of compounds and substances:
- Phosphates are salts of phosphoric acid. They activate cancer cells, create a threat of miscarriage or premature birth during pregnancy, and cause general poisoning of the body.
- Nickel is a ductile metal. Causes allergic reactions, pigment changes in the skin.
- Manganese is a metal. If ingested, it disrupts metabolic processes and brain function, causing mental disorders - irritation, excitability and hallucinations.
Class 4 – low-hazard toxic substances. These include chlorides (hydrochloric acid compounds) and sulfates (sulfuric acid salts).
How do toxic substances enter the body?
The ways in which toxic substances enter the body are different and are determined by the state in which the toxic compounds are located - gas, steam, liquid, solid particles.
Most often, toxic elements enter through the respiratory organs - the mucous membrane of the nose, larynx, bronchi and lungs. The alveolar system, which is large in area, consists of thin membranes. In this case, the poisons quickly enter the bloodstream and spread throughout the body. The central nervous system is the first to be affected. Penetrating poisons are aerosol substances. Their effect occurs 20 times faster than when taken orally.
The second place is occupied by poisoning, in which substances enter the gastrointestinal tract with food and water. Absorption from the stomach and intestines is a slow process, so it may take some time before symptoms develop. If there was food in the stomach, the absorption process slows down. The spread of toxic substances is prevented by receptors in the intestines and the liver. Therefore, food poisoning is less dangerous.
Skin is a good protective barrier. Therefore, only those substances that easily destroy its integrity penetrate the skin. Reduces the intensity of penetration of sweating, high humidity, sun tanning.
Through the mucous membranes, toxic substances penetrate quickly and immediately into the bloodstream.
The wound surface is an ideal entry gate for toxic compounds. Muscle tissue is equipped with a large number of capillaries, so poisons quickly spread throughout the body. With burns and frostbite, the absorption process slows down.
People come into contact with potentially toxic substances every day. If their quantity exceeds the norm, poisoning of the body occurs, the degree of which depends on the dose. To neutralize toxic compounds, antidotes are administered and therapy is carried out to promote the rapid elimination of poisons.