Benzene exists in a large number of organic solvents in various building materials, as well as adhesives, paints and coatings. When used in decoration, indoor benzene will exceed the standard. The use of benzene and its harm to human body
Main uses of benzene
The consumption structure of pure benzene in China is as follows: 27.25% is used to synthesize styrene, polyamide resin (cyclohexane) accounts for about 12.65%, phenol accounts for about 1 1.37%, chlorobenzene accounts for about 0.98%, nitrobenzene accounts for about 9.8%, alkylbenzene accounts for about 7.84%, and benzene accounts for about 7.84%.
Styrene is the main consumption purpose of pure benzene, and its production capacity is about 700 ~ 1 10,000 tons/year. Cyclohexane is a pure benzene consumption product next to styrene, which is mainly used to produce nylon 6 and nylon 66, with a domestic production capacity of 300,000 ~ 450,000 tons/year. Phenol is one of the chemical products that consume more pure benzene, and the demand for phenol in China is growing rapidly. It is predicted that the demand for pure benzene in China will increase at an average annual rate of 6% from 2000 to 2003. The output of chlorinated benzene is about 200,000 tons/year, and the demand for pure benzene will increase at an average annual rate of 3%. The output of nitrobenzene is about 250,000 tons/year, and it is predicted that the demand for pure benzene will increase by 5% every year in the near future. The output of alkylbenzene is about 350,000 tons/year. It is predicted that the demand for pure benzene will increase at an average annual rate of 5% in recent years. The output of maleic anhydride increased rapidly. 1990 maleic anhydride output was only 1980 tons, and the current output is about 78,000 tons/year. It is estimated that the annual demand growth rate of pure benzene will reach 7%.
Solvents for waxes, resins and oils: intermediates for synthetic chemicals and drugs. 86% benzene is used to make styrene, phenol, bad ethane and other organic substances. The rest are mainly used to make detergents, pesticides and paint removers. Benzene can be used as a component of gasoline, and its content is
In addition, toxic organic reagents such as benzene and diethyl ether are widely used in the packaging and printing industry at present, and the content of organic solvents in ink is generally 30% ~ 70%, which not only leads to the danger of flammability and explosion in the printing workshop, but also all these solvents volatilize during the printing process, which seriously pollutes the workshop and atmospheric environment and poses a threat to the health of printing workers and surrounding residents. According to statistics, during the period of 1997, the ink consumption in China was143,000 tons. In other words, at present, only one ink has released more than 50,000 tons of toxic substances such as benzene, ether and alcohol into the atmosphere in one year.
Harm of benzene to human body
"Benzene", commonly known as Tianna water, is a colorless and transparent liquid with a special aromatic smell, volatile and flammable, and the steam is explosive, which volatilizes quickly at room temperature. Inhalation of high concentration benzene vapor in a short time can lead to acute benzene poisoning, excitement or drunkenness, accompanied by symptoms of mucosal irritation. Mild dizziness, headache, nausea, vomiting, gait instability; Severe coma, convulsion, circulatory failure and even death; Inhalation of high concentration benzene in a short period of time may cause subacute benzene poisoning, dizziness, headache, fatigue, insomnia, menstrual disorder and other symptoms, as well as aplastic anemia and acute leukemia, characterized by rapid development of anemia, bleeding and infection. The harm of benzene poisoning to the body comes down to three kinds: carcinogenesis, disability and teratogenesis.
Clinical manifestations, diagnosis and treatment of benzene poisoning
Clinical manifestations are:
L, mild poisoning is excitement or drunkenness, euphoria, facial flushing, followed by drowsiness, headache, dizziness, nausea, vomiting, chest tightness, stumbling gait, and may have mild symptoms of mucosal irritation.
2, severe poisoning can appear blurred vision, tremor, shallow and fast breathing, ventricular arrhythmia, convulsions, delirium and coma. In a few serious cases, respiratory and circulatory failure and ventricular fibrillation may occur.
3. In addition to systemic poisoning, oral cavity, throat, esophagus and gastric mucosa all have irritation after taking benzene by mistake, and even cause pneumonia and collapse. Adult oral administration of 1.5m 1 can be fatal.
4, benzene liquid inhalation in the lungs, can cause pulmonary edema and pulmonary hemorrhage.
Occupational acute benzene poisoning refers to a systemic disease characterized by central nervous system inhibition caused by workers inhaling large doses of benzene vapor in a short period of time during occupational activities; Occupational chronic benzene poisoning refers to a systemic disease with hematopoietic system damage as the main manifestation caused by workers' long-term exposure to benzene vapor in occupational activities. Diagnosis:
1, diagnostic criteria
This standard specifies the diagnostic criteria, diagnostic writing format and treatment principles of occupational benzene poisoning. This standard is applicable to poisoning caused by exposure to benzene in occupational activities. This standard can be used for benzene poisoning caused by exposure to industrial toluene, xylene and other chemicals containing benzene. This standard can also be used for the diagnosis of benzene poisoning caused by exposure to benzene in non-professional activities.
2. Diagnostic principles
The diagnosis of acute benzene poisoning is based on inhaling a large amount of high-concentration benzene vapor in a short time, and the clinical manifestations are conscious. Only by excluding the changes in the central nervous system caused by other diseases can acute benzene poisoning be diagnosed. According to the degree of consciousness disorder, it is divided into mild and severe.
The diagnosis of chronic benzene poisoning is based on the occupational history of long-term close contact with benzene. The main clinical manifestations are hematopoietic inhibition and abnormal proliferation. The diagnosis of chronic benzene poisoning can only refer to the investigation of working environment and the measurement data of benzene concentration in the air on the spot, and exclude the hemogram changes caused by other reasons. Chronic benzene poisoning can be divided into three levels according to the series and degree of blood cell involvement and whether there is malignant transformation.
3, diagnosis and grading
3. 1, acute benzene poisoning
3. 1. 1, acute mild poisoning
Dizziness, headache, nausea, vomiting, excitement, stumbling and other drunken States may occur after inhaling high-concentration benzene vapor for a short time, and may be accompanied by symptoms of mucosal irritation. The increase of breath benzene, blood benzene and urine phenol can be used as indicators of benzene exposure.
3. 1.2, acute severe poisoning
After inhaling high concentration benzene vapor, fidgety, confusion, coma, convulsion, blood pressure drop and even respiratory and circulatory failure occur. The measured values of breath benzene, blood benzene and urine phenol increased, which can be used as indicators of benzene exposure.
3.2, chronic poisoning
3.2. 1, observation object
Workers exposed to benzene found one of the following changes in blood test, and those who did not improve every 1 ~ 2 weeks within 3 months and could not find other reasons could be listed as observation objects.
A) The white blood cell count fluctuates between 4 ~ 4.5×109/L (4000 ~ 4500/mm3);
B) The platelet count fluctuates between 60 ~ 80×109/L (60 ~ 80000/mm3);
C) The red blood cell count of male is lower than 4×1012/L (4 million /mm3) and that of female is lower than 3.5×10/2/L (3.5 million/mm3); The quantitative hemoglobin of male is lower than 120g/L (12g/DL) and that of female is lower than110g/l (1LG/dl).
D) The peripheral blood cell count increases, and naive or abnormal blood cells appear.
3.2.2, chronic mild poisoning
If the white blood cell count is continuously or basically lower than 4× 109/L (4000/mm3) or the neutrophil count is lower than 2× 109/L (2000/mm3), check it every 1 ~ 2 weeks within 3 months. Often appear dizziness, headache, fatigue, insomnia, memory loss and other symptoms.
3.2.3, chronic moderate poisoning
Most of them have chronic mild poisoning symptoms and are prone to infection and/or bleeding. Meet one of the following conditions:
A) White blood cell count is lower than 4× 109/L(4000/mm3) or neutrophil is lower than 2× 109/L (2000/mm3), and platelet count is lower than 60×109/L (60000/mm3).
B) White blood cell count is lower than 3× 109/l(3000/mm3) or neutrophil is lower than1.5×109/L (1500/mm3).
3.2.4, chronic severe poisoning
One of the following situations occurs:
A), pancytopenia;
B), aplastic anemia;
C), myelodysplastic syndrome;
D), leukemia.
4. Principles of treatment
4. 1, acute poisoning
Leave the scene quickly, move the poisoned patient to fresh air, take off the clothes contaminated by benzene immediately, wash the contaminated skin with soapy water, and keep warm. The principle of first aid is the same as that of internal medicine, and gastric lavage is given to people who take orally. Glucuronic acid can be given symptomatic and supportive treatment. Pay attention to the prevention and treatment of brain edema. You should stay in bed in the acute stage. Epinephrine should not be used in patients with cardiac arrest.
4.2, chronic poisoning
There is no specific antidote, and the treatment is mainly symptomatic treatment of blood diseases caused by hematopoietic system injury.
5, labor ability appraisal
5. 1, acute poisoning
After mild poisoning is cured, it usually takes 3 to 7 days to take effect. The rest time of severe poisoning should depend on the degree of recovery.
5.2, chronic poisoning
Once diagnosed, you should be removed from the work of contacting toxic substances such as benzene. During the illness, work or rest should be arranged according to the illness.
5.2. 1, mild poisoning
Generally, you can engage in light work or part-time work.
5.2.2 Moderate poisoning
According to the condition, arrange rest properly.
5.2.3, severe poisoning
Shut it all down.
5.3, observation object
According to occupational contraindications, benzene operation should be transferred.
6, health inspection requirements
6. 1, check your health
6. 1. 1. Workers exposed to benzene should undergo employment physical examination and physical examination once a year after work.
6. 1.2. Physical examination items include internal medicine examination, as well as white blood cell count (cell classification if possible), red blood cell count and/or hemoglobin quantification, and platelet count.
6.2, observation object review
6.2. 1. Generally, the observed object will be rechecked once every l to March, and will take part in the routine physical examination next year.
6.2.2, laboratory review project
A) Blood red blood cell count, hemoglobin quantification, white blood cell count and its classification, platelet count and record abnormal blood cells;
B) Conduct bone marrow smear and other relevant blood laboratory tests as required.
6.3, chronic poisoning follow-up
6.3. 1. Follow-up is generally conducted once every l to 3 months. Blood examination items include red blood cell count, hemoglobin quantification, white blood cell count and its classification, platelet count, and record abnormal blood cells.
6.3。 2, blood cell count continues to be abnormal or abnormal shape, bone marrow smear and other related blood laboratory tests should be done.
6.3.3. Follow-up period: Even if the hemogram recovers, it is generally not less than 10 years.
7. Occupational contraindications
A) During the pre-employment physical examination, the blood test result is lower than the normal reference value;
B) Various blood diseases;
C), serious systemic skin disease;
D) menorrhagia or functional uterine bleeding.
The chemical structure of benzene is very stable and it is not easy to degrade under natural environmental conditions. It can cause lasting and serious pollution to soil, water and atmosphere, and its harm to animals, plants and human beings can not be ignored. Therefore, we call on all enterprises related to production, application and transportation in the world to strictly implement relevant international conventions and industrial norms for the production, application, storage and transportation of hazardous chemicals.