Acute and chronic benzene poisoning
Modern production can not be imagined without such a substance as benzene. It entered our life in 1825 and since then it can be found in many areas, including human life. The widespread use of benzene in industry can not exclude man-made accidents that existed in history. For example, accidents at enterprises in China, Lipetsk and other regions led to the leakage of this hydrocarbon. Nobody is immune from poisoning, especially when it comes to people who work with this substance and who are in contact with it for a long time.
Benzene - what is this substance, where it is applied and how does it act on a person? How to provide first aid for acute poisoning, what is the treatment of chronic intoxication?
What is benzene and where is it used?
Benzene is an aliphatic hydrocarbon compound, which is a liquid without color, with a characteristic aroma. Benzene well refracts light and quickly evaporates at room temperature. It boils at 80.5 ºC, freezing turns into a crystalline substance. Benzene vapors form a flammable mixture when mixed with air. It is readily soluble in all solvents (chloroform, ethanol, ether), except water. It is a solvent for oils, fats, resins, sulfur, alkaloids, iodine, phosphorus.
Benzene is prepared from acetylene. The catalyst for this reaction is nickel. Methods for the production of benzene:
- Coking coal (used increasingly rarely, the benzene thus obtained has impurities);
- processing of gasoline fractions of petroleum (half of benzene is produced by this method);
- from acetylene at high temperature in the presence of activated carbon.
Where is benzene used? This is the most common aromatic hydrocarbon used in production.
It is a part of:
- synthetic fibers;
- motor fuel;
- solvents of varnishes and paints.
In the chemical industry, it is used as a solvent. Its main application at the moment is the synthesis of ethylbenzene, cumene, cyclohexane. Of these substances in the future produce drugs, dyes.
The following categories of the population have a risk of benzene intoxication:
- people directly involved in its production, storage, transportation;
- persons carrying out the washing of tanks transporting benzene;
- workers of oil refineries;
- laboratory assistants taking part in distillation of oil;
- repairmen of pumps;
- affected by the fire from burning plastic, rubber, rubber.
Benzene penetrates into the human body with inhaled air in the form of vapors. Penetration through the respiratory system is the leading way of getting this substance. In the second place is the percutaneous path. But it has less significance, compared to the air one.
What is harmful benzene? With short-term inhalation of benzene vapor, no poisoning occurs. With prolonged contact or exposure to high doses of this poisonous substance, it penetrates into the blood and begins to circulate in the body. It is then excreted mainly through the respiratory tract, partly by the kidneys. When breastfeeding, it stands out and with milk.
Upon contact with the skin, benzene causes its dryness, there are cracks, itching, redness, swelling, bubbling out.
Benzene exerts a toxic effect on all organs and systems of the body. Poisoning is acute and chronic. In acute poisoning, the respiratory system, vessels, brain, adrenals and liver suffer more, and in the chronic, the hemopoietic system is the most affected.
The toxic dose for poisoning with benzene vapor is 319 mg / m³. The lethal dose on inhalation is 63,803 mg / m³ for 5 minutes. When consumed internally for a fatal outcome, 10-20 ml is sufficient. Systematic exposure to a dose of 0.12-0.19 mg / L leads to chronic poisoning.
With systematic intoxication with benzene, the following action is observed on the body:
- harmful effects on the embryo and fetus;
- a negative effect on the reproductive organs.
Additional effects of benzene:
- violation of the balance of B vitamins;
Acute benzene poisoning is rare, in contrast to chronic.
Acute poisoning with benzene can occur as a result of an accident, an industrial accident, violation of rules in the workplace, substance abuse. In this case, a large dose of the substance enters the body at once or for a short period of time.
The first responds to the nervous system:
- dizziness appears;
- noise in ears;
- euphoric state, which is replaced by a headache, nausea, vomiting, impaired coordination of movements.
If intoxication was easy, the poisoning will be limited to the above symptoms and after a while will pass without a trace.
With an average degree of poisoning, the behavior of a person becomes inadequate, restless, the skin turns pale, the body temperature drops, breathing becomes faster, and the pulse begins to weaken. If assistance is not provided on time, the situation can be complicated by convulsions and coma. Such poisoning can pass without a trace, and can leave after itself an astheno-vegetative syndrome (violation of transmission of nerve impulses to tissues).
When heavy intoxication, a person instantly loses consciousness, a toxic coma sets in, a stop of breathing due to paralysis of the respiratory musculature occurs. In most cases, the outcome of severe intoxication is death.
What other symptoms of acute benzene poisoning can be noticed?
In the blood, methhemoglobin is formed. It does not bind to oxygen and does not transfer it to the tissues. The consequence is a cellular oxygen starvation. The cells of the heart muscle and the nerves suffer the most.
- Benzene has a destructive effect on red blood cells. Poisoning is accompanied by anemia.
- Liver can be signaled by jaundice.
- Vascular damage causes the formation of hemorrhages and ulcers on the skin and mucous membranes.
- Some benzene compounds irritate the respiratory tract, causing coughing, perspiration, sneezing.
- Blood in the urine can indicate a defeat of the genitourinary system. Most often develops cystitis with hemorrhages and ulcers in the bladder.
Symptoms, depending on the severity of the poisoning, may appear after a few minutes or hours after the substance has entered the body.
First aid and treatment for acute poisoning
The first help in poisoning with benzene is reduced to the following actions.
Termination of contact with benzene. The victim needs to ensure the influx of fresh air - take out of the room, open the window. In case of contact with caustic material on the skin and mucous membranes - rinse with 1% sodium hydrogen carbonate solution (baking soda).
- In severe cases - holding artificial respiration and indirect heart massage.
- Call an ambulance.
Treatment of acute poisoning consists in maintaining, restoring the functions of organs and systems:
- metabolic and antioxidant, oxygen therapy;
- elimination of cardiac arrhythmias;
- elimination of seizures;
- restoration of the normal rhythm of breathing.
This condition develops as a result of prolonged contact with small, but toxic doses. Chronic intoxication with benzene in contrast to acute develops slowly. You can suspect it by accident or by purposeful search. The hemopoietic system is affected, namely, the bone marrow. After the hematopoiesis, the nervous system suffers.
The patient begins to worry about time:
- noise in the head and ears;
- an increase in the rhythm of the heart.
Then, nausea, vomiting, and pain in the bones are added. Increased bleeding manifests nasal, uterine bleeding, the appearance of blood when cleaning teeth, hemorrhages with minor bruises. Anemia is manifested by pallor, hair loss, brittle nails, decreased physical and mental performance.
In neglected cases, you can see the following signs of chronic benzene poisoning:
- Muscular twitching, trembling of hands, speech and movement coordination;
- pain in the legs, impaired sensation;
- pain in the liver and increase in its size, a venous pattern on the abdomen around the navel with the development of cirrhosis;
- disorders of digestion: lack of enzymes, increased acidity of the stomach, gastritis, ulcer;
- hypertension, increased heart size, high heart rate;
- women - violations of the menstrual cycle, infertility, chronic miscarriage.
Benzene is a carcinogen. It causes mutations and leads to the appearance of atypical cells in the blood. Leukemia with chronic poisoning can develop after 5-10 years. Termination of contact with benzene is not a guarantee of protection against leukemia. If chronic poisoning already exists, then everyone is at risk, both employees and employees who have left the production.
Chronic poisoning can also cause aplastic anemia, myelodysplastic syndrome and bone marrow diseases.
Treatment of chronic poisoning
In case of chronic poisoning with benzene, the following measures are taken:
- cessation of contact with the substance;
stimulation of hematopoiesis;
- transfusion of plasma and administration of blood products;
- vitamin therapy (groups B and PP);
- prescribe drugs that improve cerebral and cardiac blood flow;
- metabolic therapy for the brain and heart;
- antioxidant therapy;
- shows drugs that protect the liver, essential acids.
Benzene is a highly toxic, carcinogenic substance that, at high concentrations, causes acute poisoning, often accompanied by loss of consciousness and possible fatal outcome. Severe poisoning and chronic intoxication cause long-term health problems.