Occupational Diseases / / August 12, 2017
Benzene - a colorless liquid that evaporates easily at normal room temperature.Couples benzene 2.7 times heavier than air.the most widely used toluene from benzene homologues (methylbenzene), xylene (xylene), and styrene (vinylbenzene).Volatility toluene 2 times less than the benzene, xylene - 4.5 times.Benzene is used for the production of phenol, nitrobenzene, maleic anhydride.Styrene is characterized by its ability to polymerize quickly, particularly to light and heat.
Toluene and xylene are used as solvents, paints and varnishes, as a high-octane components of motor gasoline and aviation.Toluene is used for TNT, caprolactam, and aniline in the pharmaceutical industry, xylene - for toluene and xylidine.Styrene polymerization is used to produce plastics, synthetic rubbers in the manufacture of polyester resins and plastics.
in Russia in many industries use benzene is prohibited, and it is replaced with toluene or xylene.It turns benzene from coal tar or petroleum.Maximum allowable concentration for
primary route of exposure - in the form of vapors (through the respiratory tract) and in the liquid state (through the skin).Benzene and its homologues are distinguished mostly light unchanged.These substances are found in acute poisoning in the brain, adrenal glands, liver and blood;chronic - in adipose tissue and bone marrow.Metabolism
benzene and its homologues in the body is different.Benzene is oxidized to phenol and polyphenols that bind and glucuronic sulfuric acids and organic sulfates in the form are excreted in urine.Metabolism homologues occurs due to the oxidation of the side chains to form alcohols, acids and aldehydes.Toluene and styrene are converted to benzoic acid which is coupled with glycine to form hippuric acid.Xylene converted to toluic acid.These acids are excreted in urine.
general nature of the action : narcotic and somewhat jerky.Benzene acts on the nervous system and organs of hematopoiesis.Benzene homologues have also irritating effect which is particularly pronounced in styrene.The latter, moreover, cause degenerative changes in parenchymal organs (particularly liver), endocrine disorders.Action pas blood system have homologues of benzene are much less pronounced than that of benzene.
Acute poisoning in industrial environments are rare: in case of emergency, cleaning of tanks out of these materials, when used as part of quick-drying paint when working in confined spaces, transfusion in poorly ventilated areas.Styrene poisoning may occur, when receiving the plastic polymer polymerized styrene not all, and in the depolymerization, especially when heated polymer.
Symptoms Mild acute poisoning resembles benzene intoxication: headache, dizziness, paresthesia, confusion, vomiting.In more severe cases - loss of consciousness, muscle twitching, which may go into spasms and tonic clonic nature, the pupils are dilated, poorly responsive to light, learning breathing, then slow down, the body temperature drops, skin pale.Pulse weak filling, speeded up, blood pressure falls.
The action homologues of benzene, except the above symptoms, there is tearing, mucus from the nose may be nosebleeds.At very high concentrations may occur (sometimes immediately), loss of consciousness and death from paralysis of the respiratory and vascular center.After severe poisoning long-term (1-2 months) kept the phenomenon asthenia.There are cases of complications such as pulmonary disease, liver disease (for benzene and styrene intoxication), cardiac and vasomotor disorders, as well as dermatitis.
Complaints: headache, dizziness, weakness, fatigue, irritability, tearfulness, sleep disturbances, poor appetite, unpleasant sensations in the heart, bleeding gums, nosebleeds, bruising on the body.The women - a tendency to menorrhagia.An early sign of chronic poisoning are functional changes in the nervous system: neurasthenic or asthenic syndrome with autonomic dysfunction.
Vegetative-sensitive polyneuritis of the upper extremities are developed mainly for those workers who have to work in the process of washing hands or contaminate compositions containing benzene or its homologues.Progression of intoxication by benzene and styrene can cause the appearance of organic changes of the nervous system.The latter have the character of diffuse brain injury (toxic encephalopathy).When poisoning with toluene and xylene changes in the nervous system are limited to the functional stage.
Chronic intoxication styrene observed violations of the secretory and motor functions of the stomach.The most common and relatively quickly (within 5-7 years) may develop liver syndrome - a painful liver, increased slightly, its functions are disrupted.Dysproteinemia - reduction of serum albumin and increase in globulin fractions all.Reduced albumin-globulin ratio.
intoxication benzene observed characteristic changes in the blood, which are often combined with neurological symptoms.These changes initially are qualitative: hypersegmentation neutrophils with abnormal grain protoplasm Anisocytosis, poikilocytosis, polihromaziya.
At the beginning of intoxication leukocytosis may occur (usually male), then developed transient leukopenia which the progression of intoxication becomes more persistent and severe.In parallel with the increasing leukopenia or thrombocytopenia develop later and more pronounced reaction of red blood cells - reticulocytosis, anemia.
In severe cases of benzene poisoning may develop agranulocytosis.Changes in the blood can not go in a strict sequence.In the bone marrow with the initial forms of intoxication observed stimulation of hematopoiesis, especially the white germ.Erythropoiesis is disturbed to a lesser extent.In severe cases, bone marrow aplasia and evolving phenomenon of fatty degeneration.
When poisoning with toluene and xylene blood changes are less pronounced (mostly labile blood parameters observed).Often observed decrease in the number of red blood cells, after having qualitative changes of leucocytes.Changing the number of white blood cells is less common and is expressed moderately.
In chronic poisoning styrene in blood observed increased hemoglobin and red blood cells at a relatively low color index, reticulocytosis;increased content basophilic-grained red blood cells;tendency to leukocytosis, neutrophilia, lymph and monocytosis.Moderate thrombocytopenia.In the future - anemizatsiya (more pronounced in women), leukopenia.
observed lability of heart rate, blood pressure, with a tendency to hypotension, degenerative changes in the myocardium.
Frequent contact with benzene and its homologues may experience skin conditions: dry, cracked, red, and then develop eczema and dermatitis, most often they are observed in contact with xylene.If poisoning benzene homologues also arise rinofaringolaringity subatrophic and atrophic character.Characteristic pronounced chronic poisoning by benzene and styrene is a hemorrhagic syndrome: bleeding in the skin, bleeding from the nose, gums, and parenchymal organs.
of chronic poisoning: initial forms of poisoning and reversible with appropriate treatment and rational employment pass (from 2 to 4 months period).Sometimes, however, even with removal from exposure to benzene disease can progress - developing organic lesion of the nervous system, changes in the bone marrow.
severe forms of intoxication characterized by high resistance, and the process in such cases is often irreversible.Sharply reduced resistance to infections.Exposure to benzene and its homologs contributes to the development of any blood diseases: acute and chronic leukemia, severe anemia, polycythemia.
Treatment Treatment of chronic intoxications is mainly symptomatic.When the nervous system lesions: small doses of caffeine bromine intravenously with ascorbic acid, glucose, calcium gluconate, biogenic stimulants, vitamins B1 and B12, novocaine electrophoresis (at polyneuritis).If it affects the hematopoietic system: vitamins B6, B12 is, folic acid, fractional blood transfusion.Prevention of liver failure.
disability When the primary forms of chronic intoxication - the temporary transfer of work out of contact with benzene and its homologues;sanatorium treatment, vacation, returning to work - under the close supervision of a dynamic.In case of resistance, relapse or progression of intoxication - transfer to permanent employment, not associated with exposure to toxic substances.If necessary, re-qualification or expressed forms of intoxication - a direction on VTEK (occupational disability).
sealing equipment, continuous monitoring of the concentration of benzene and its homologues in the air of industrial premises, respiratory protection (work in gas masks in the presence of high concentrations), the skin (clothing impermeable to solvent material, the use of protective ointments and pastes).Personal hygiene measures.
on work related to the production and use of benzene, women and persons under the age of 18 are not allowed (the latter is also not allowed to work with the homologues of benzene).Pregnant and lactating women should be suspended from work associated with exposure to benzene homologues.