The effect of formaldehyde and formalin on the human body

Formalin: what is it?

This substance is most often used as a disinfectant.
Its solutions (0.5-1%) are used to wash the skin with severe sweating (legs, armpits) and bromidrosis (pungent odor of sweat). Formalin effectively reduces the secretion of epidermal glands, but it cannot be used daily. In some cases, it is used for douching (at a concentration of 0.05%), washing the tonsil crypts (0.25%). This substance is included in the preparations “Lysoform”, “Formidron”, “Formalin Ointment”, “Teymurov’s Paste”. Side effects when using this solution: irritation and drying of the skin, which disappears when lubricated with a rich cream or vegetable oil. Formalin, the use of which is contraindicated in case of inflammatory processes or irritation of the epidermis, can be used only after they have been eliminated.

This solution is also used to disinfect medical instruments and patient belongings. The use in this case involves only 0.5% formaldehyde. What kind of drug is this? For medical use, only a 10% solution is produced in 100 ml glass bottles. Store formalin in a well-closed container in a dark place at a temperature of at least 9˚C. This substance is considered toxic to humans and animals.

Synonym: formaldehyde.

Contains 36.5-37.5% formaldehyde.

Properties.

It is a transparent, colorless liquid with a peculiar pungent odor, soluble in water and alcohol in any ratio. Incompatible with oxidizing agents, camphor, menthol, thymol and resorcinol. It is stabilized by adding methyl alcohol, but not more than 1%.

Release form. Produced in well-closed glass or metal containers.

Store in a place protected from light, at a temperature not lower than 9°C. During long-term storage in the cold, formaldehyde undergoes polymerization to form paraformaldehyde, which precipitates in the form of white flakes that disappear when heated.

Action and application.

Formaldehyde has a pronounced antimicrobial effect due to its ability to attach to the amino groups of protein molecules, and is also a good deodorizing agent due to its ability to bind ammonia in the air. In high concentrations it has an astringent and cauterizing effect on the mucous membranes.

In case of acute poisoning of cattle with urea, the effect of formaldehyde is that it binds ammonia in the rumen to form non-toxic hexamethylenetetramine, inhibits the urease enzyme, slowing down the hydrolysis of the remaining urea, and lowers the pH of the contents, preventing further absorption of unbound ammonia. With a single injection into the scar, the effect of the drug lasts for 1 hour.

Formaldehyde solution is indicated for the treatment of cattle with urea poisoning.

To treat sick animals, the drug is prepared by dissolving a therapeutic dose of official formaldehyde solution (0.3 ml per 1 kg of live weight) in 1 liter of water. For example, if the animal’s body weight is 500 kg, then to prepare the drug, take 150 ml of formaldehyde solution (0.3 ml x 500 kg) per 1 liter of water.

When clinical signs of animal poisoning with urea appear, the drug is administered once into the rumen through the wall in the area of ​​the left hungry fossa using a Janet syringe using a 10-12 cm long needle.

At recommended doses it does not cause side effects or complications. In excessive doses, after administration it can cause slight depression, trembling of the body muscles, and hypotension of the forestomach. The side effects of formaldehyde solution can be reduced by administering protein orally, gastric lavage with a suspension of activated carbon, and introducing ammonium acetate into the rumen at a dose of 15-25 g.

In case of acute poisoning of cattle with urea, there are no contraindications to the use of formaldehyde solution.

Formaldehyde reacts well with many substances, including proteins. It has an irritating, cauterizing, antimicrobial, antiparasitic, deodorizing and drying effect. Kills non-spore-forming microorganisms, spore forms of microbes, viruses and fungi. Anthrax spores die within three hours when exposed to a warm (30°C) 4% formaldehyde solution. It has a detrimental effect on scabies mites, flies, their larvae and other parasites. Increasing the temperature and relative humidity in the premises increases the antimicrobial activity of the drug. The antimicrobial action is based on the interaction of formaldehyde with protoplasm and the removal of oxygen from protein compounds, coagulation and denaturation of the bacterial cell protein. At temperatures below 0°C, formaldehyde has no harmful effect on microbes.

Formalin thickens and dries out the skin, and with frequent use, the skin becomes dry, brittle and eczema develops. Aqueous solutions of formaldehyde, after oral use, have an antiseptic and anti-fermentation effect, and in cases of ingestion of concentrated solutions, gastroenteritis develops.

Used as one of the most versatile and best means for disinfecting livestock buildings. Can be used in aqueous solutions, in a gaseous state, in the form of aerosols, both in pure form and in mixtures with other chemicals. To disinfect premises for foot-and-mouth disease, Aujeszky's disease, pasteurellosis, swine erysipelas, poultry pullorosis, use a 1% solution of formaldehyde; for infectious vaginitis, swine paratyphoid fever, swine fever, sheep pox, washing horses - 2%, for anthrax - 4% solution. An alkaline solution of formaldehyde is recommended for disinfection for dermatomycosis (1% caustic soda and 2% formaldehyde), and for avian tuberculosis (3% caustic soda and 3% formaldehyde). Disinfection is carried out at a temperature of 25-30°C.

Formaldehyde is used for gas disinfection of hermetically sealed premises, containers and equipment. To do this, pour 45 parts by weight of formaldehyde (40% formaldehyde) and 22 parts of water into a metal or porcelain bowl, and then add 30 parts of potassium permanganate. The staff leaves the premises and closes it. When formalin interacts with potassium permanganate, a violent reaction occurs, accompanied by high temperature, as a result of which formalin quickly boils and evaporates. For disinfection, take 40-50 ml of formaldehyde (40% formaldehyde) per 1 m3 of room at a temperature of 25-30°C, relative humidity 70% and exposure for 5-6 hours. After this, the room is thoroughly ventilated.

In this way, hard containers (cages, boxes, shovels, forks, etc.), soft equipment and workwear are disinfected in steam-formalin chambers. The required relative humidity (65-70%) and temperature (60°C) are created in the chamber; formaldehyde consumption is 40-50 ml per 1 m3 with exposure for one hour. At the end of disinfection, to neutralize formalin, half the amount of ammonia is introduced into the chamber and after 5 minutes the chamber is unloaded. To disinfect the spore form of pathogens, the amount of formalin is increased to 100 ml per 1 m3.

To disinfect premises, formaldehyde can be used in an aerosol form at the rate of 20 ml of formaldehyde (40%) per 1 m3 with an exposure of 5-6 hours. For simultaneous disinfection and disinsection, take formalin with the addition of 5% chlorophos or 0.1% DDVP. For tuberculosis and spore forms of microorganisms, 40 ml of formalin is consumed per 1 m3. For disinfection barriers and disinfectants, an alkaline formaldehyde solution containing 3% formaldehyde and 3% sodium hydroxide is used.

To disinfect vehicles or other equipment in areas of foot-and-mouth disease, a 2% formaldehyde solution or formaldehyde aerosol is used at the rate of 60 ml of a 40% formaldehyde solution per 1 m3 of room with an exposure of 30 minutes. Car wheels are disinfected in disinfection barriers filled with an alkaline solution of formaldehyde (3% sodium hydroxide and formaldehyde). For foot rot of sheep and goats, after trimming the hooves, the animals are passed through a foot bath with a 10% formaldehyde solution or a 5% paraform solution. In this case, disinfection of premises, pens, equipment, care items, vehicles and surgical instruments is carried out with a 10% formaldehyde solution or a 5% paraform solution. The same solution is used in the form of foot baths to prevent foot rot in apparently healthy sheep and goats. A 3% formaldehyde solution is recommended for disinfection of fish farming facilities (tanks, tubs, carts, etc.). For aerosol disinfection of meat processing plants infected with the foot-and-mouth disease virus, a 20% formaldehyde solution of 30-40 ml per 1 m3 with an exposure of 2 hours is recommended.

Formalin is used as a disinfectant and deodorant for washing hands, disinfecting instruments (0.5% solution), for douching (0.05% solution); sterilization of cotton and linen threads and catgut (threads are immersed in a 4% solution for 24 hours, and catgut for 72). A 2.5% alcohol or aqueous solution of formaldehyde in the form of gauze applications is prescribed for necrobacillosis (at the onset of the disease or in the gangrenous form). For necrobacillosis, a liniment consisting of equal parts of formalin, creolin and tar is recommended. For frostbite of the third degree, it is recommended to apply an anti-gangrenous liquid consisting of formalin (5 parts), tricresol (5 parts) and distilled water (10 parts). A 5% alcohol solution of formaldehyde is used to treat the surgical field.

Formalin is used to preserve pathological material, vaccines and some serums.

To disinfect the premises of rabbit farms and complexes, use a 1% formaldehyde solution, as well as an aerosol from a 36-40% formaldehyde solution at the rate of 10 ml per 1 m3 of premises with an exposure of 6 hours. Then the room is ventilated and excess formaldehyde is neutralized with an ammonia solution. Vehicles in complexes, equipment for caring for rabbits, as well as premises at beef production enterprises are disinfected with a 2% formaldehyde solution. Pre-launch disinfection of enclosed spaces is carried out with formaldehyde aerosols (36-40%) at the rate of 20 ml per 1 m3 of room with exposure for 24 hours.

Chemical composition of formalin

How is formaldehyde obtained? The formula of this substance is CH2O. Formaldehyde (formic acid aldehyde), which is a colorless gas with a suffocating odor, turns into a clear liquid when cooled to -21 ° C. Its melting point is -92° C. Upon oxidation, it turns into formic acid. Formaldehyde is produced by exposing methyl alcohol to methyl alcohol in the form of vapor in the presence of catalysts. Of these, silver has proven to be particularly productive, although the industry uses copper, which is more readily available. The resulting distillation accumulates water, resulting in formaldehyde. It may contain impurities of acetone, acetic or formic acid. When formaldehyde is evaporated, the residue is a dense mass of polymers that are insoluble in cold water.

Physico-chemical properties and preparation

Formaldehyde (methanal) is an aliphatic aldehyde of methyl alcohol and formic acid, first synthesized by the Russian chemist Butlerov.

Small amounts of it in nature are naturally formed during photosynthesis of plants and metabolic processes of living organisms. Much more formaldehyde is emitted into the environment through automobile exhaust and waste from leather, woodworking and furniture production. Chemical enterprises that produce thermoset polymers, cosmetics and pharmaceutical products also contribute. Under the influence of sunlight and oxygen in the air, formic aldehyde becomes an integral part of the urban atmosphere.

Compared to residents of villages and villages, residents of industrial cities are more exposed to formaldehyde, and contact with it is much more likely indoors than in nature.

Formaldehyde has the formula CH2O, density 0.8153 g/cc at a temperature of -20°C and molar mass 30.03 grams/mol. Sometimes there are other names on the Internet: fordamelhyde, folmadehyde, falmardehyde. It is a colorless gas that can ignite from an open fire, and, being heavier than air, forms explosive mixtures with it. Participates in all reactions characteristic of aliphatic aldehydes, is very soluble in water and alcohols, and has average solubility in benzene and other organic solvents.

Its 37% aqueous protein denaturing solution is called formaldehyde and is widely used for tanning and stabilizing biological materials. During storage, it becomes cloudy, because the resulting paraformaldehyde precipitates into a white precipitate. Methanal exhibits antimicrobial activity against gram-positive and gram-negative bacteria, yeast-like and mold fungi. The substance does not accumulate in the environment, because in the sun or with the help of bacteria from soil and water it decomposes into formic acid and carbon monoxide.

The technology of the industrial contact catalytic process was developed by the Russian chemist Orlov. Formaldehyde is produced by the oxidative conversion of methane on aluminum phosphate at 450 °C or methanol, with differences in catalysts and process temperatures:

• for iron-molybdenum - at 300 °C;
• on silver - at 650 °C.

In laboratory conditions, it can be synthesized by the oxidation of methanol on zinc-copper catalysts at 600 °C, the thermal decomposition of zinc formate, or the depolymerization of paraformaldehyde.

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Using formaldehyde solution

Formalin is used as a convenient source of formaldehyde used in the production of polyvinyl formalin. It is also indispensable as an antiseptic for disinfecting premises, tools, clothing, and tanning leather raw materials. It is used for embalming organic substances (organisms and organs). Formalin, the use of which for the preservation of anatomical preparations does not surprise anyone, is also used as a fungicide. Many plant growers treat seeds, tubers, and root crops with this solution before planting and sowing.

Formalin, the quality of which is controlled by GOST 1625-89, is used in the manufacture of synthetic resins, surfactants, rubber, polyhydric alcohols and some other methylene derivatives. Formaldehyde solution is also used in the textile industry. It is used to improve the consumer properties of fabric in terms of resistance to shrinkage and creasing. In the paper industry, formaldehyde improves paper quality and strength.

Emission classes for chipboard production

The main source of formaldehyde in residential and office premises is furniture and building materials, so it has become important to study its release (emission) from them. During the first year and a half from the moment the sofa or laminate is manufactured, the most intense emission occurs, leading to an increase in the formaldehyde content in the air of the apartment. Then it decreases, but in damp and poorly ventilated areas, the process of releasing toxins will continue for many years.

In accordance with international requirements, chipboard manufacturers assign emission classes to their products, indicating the level of free formaldehyde content in 100 g of absolutely dry matter. Class markings and their characteristics are as follows:

• E-0 completely eliminates the content of formaldehyde, indicating the environmental friendliness of the product. MDF and laminate are safe even with a significant increase in temperature and humidity in the room.
• E-0.5 indicates that the formaldehyde content in dry material is up to 5 mg per 100 g of weight. This quality meets the requirements for export products and foreign orders (for example, the Swedish concern IKEA) placed in Russian factories.
• E-1 states that the formaldehyde content ranges from 5 to 10 mg inclusive for every 100 g of weight. Such boards can be used to make children's furniture.
• E-2 indicates a content of 10 to 30 mg of substance per 100 g of material. The production of boards with large amounts of formaldehyde is prohibited.

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Precautions when working with formaldehyde

When purchasing this substance, do not forget how dangerous formaldehyde can be. What are these precautions? The guaranteed shelf life of this substance from the date of manufacture is 90 days. Formalin is sold in bottles, canisters, and barrels. The formaldehyde solution should be kept as far as possible from children. When formalin is taken orally, a burning sensation and pain appear in the esophagus and stomach. After this, vomiting of blood appears. Also, formaldehyde poisoning causes coughing, sneezing, hyperthermia of the eye mucosa, and shortness of breath. A person may experience convulsions, dizziness, and panic attacks. In some cases, formalin poisoning ends in death, which occurs due to respiratory paralysis and asphyxia. Lethal dose – 10-15 ml of 35% solution. The smell of formaldehyde in high concentrations can also cause an allergic reaction.

Effect on humans and signs of damage

In medicines and cosmetics, formaldehyde has a rather beneficial effect on the human body: it binds ammonia vapor, which gives an unpleasant odor to sweat, and blocks the development of microbes that cause aromatization in the armpits and feet. But if the permissible concentration is exceeded, protein coagulation and fixation occurs, which at least leads to irritation, itching and rash. Uncontrolled inhalation of formaldehyde vapor or ingestion of solutions leads to the development of acute suffocation and serious poisoning, which is more severe the greater the percentage of toxin and the time of exposure.

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It is not for nothing that the World Health Organization has included it in the list of substances that lead to health problems. Allergen, mutagen and carcinogen that causes damage to the respiratory and nervous systems - all this is about formaldehyde. Hazard class - second (highly dangerous substance) the maximum one-time limit of permissible concentration of which in the open air is 0.05 mg / cubic meter. meter, in the air of a confined space - 0.5 mg / cubic meter. meter, in natural water - 0.05 mg/liter, in soil - 7 mg/kg. All this is also true for formaldehyde, whose hazard class is also second. At a concentration of 20 mg/cubic meter, death occurs within 30 minutes.

The first signs of exceeding the concentration of formaldehyde in the air of the working area:

• pain in the eyes;
• lacrimation and runny nose;
• cough and shortness of breath;
• headache;
• convulsions and suffocation;
• impaired motor coordination.

With prolonged inhalation of high concentrations, the following develops:

• dilated pupils;
• acute conjunctivitis;
• rhinitis;
• bronchitis;
• swelling of the mucous membranes of the pharynx and lungs;
• pain in the mouth and behind the sternum;
• severe pain in the abdomen, thirst;
• nausea, vomiting blood.

If you accidentally drink a formaldehyde solution, an instant burn of the esophagus occurs and an increase in the volume of the respiratory organs. When concentrated solutions come into contact with the skin, deep necrosis of the affected area occurs with intoxication, causing renal and liver failure. The gradual accumulation of formaldehyde in the air of unventilated rooms provokes:

• a state of general weakness and weakness;
• depression and fear;
• frequent headaches;
• development of asthma, dermatitis and allergic eczema;
• insomnia, unsteady gait;
• pale skin;
• softening and brittleness of nails;
• in women - hormonal imbalance, menstrual cycle disruption.

Poisoning

Acute poisoning with formaldehyde solution is rare. These are mainly domestic and industrial accidents. During acute intoxication, the victim experiences headaches, dizziness, loss of orientation in space, and sometimes doctors record general toxic shock with damage to the liver and kidneys. Even a slight excess of formaldehyde vapor indoors can cause headaches, nausea and vomiting. Severe intoxication with vapors threatens the victim with spasm of the larynx, difficulty breathing and pulmonary edema, leading to death. If the solution gets inside, vomiting, acute pain syndrome, and general toxic shock occur. The lethal dose if the solution is swallowed is 50 ml.