Beryllium Poison And Industrial Hygiene
Beryllium and its compounds are toxic to the human body and are one of the most toxic elements. Industrial hygiene and environmental protection of beryllium operations must meet safety standards.
Beryllium Poisoning Recognition Process
In 1933, Germany first reported the poisoning of workers exposed to beryllium compounds, and in 1942, it was reported that workers exposed to beryllium silicate and beryllium hydroxide were poisoned by beryllium. The United States first put forward the report of beryllium poisoning in 1943, and implemented the occupational beryllium poisoning patient registration system in 1951. By the end of 1977, 887 cases had been registered. Western countries have also reported cases of poisoning of residents around beryllium factories. In the more than 40 years of production and consumption of beryllium in the former Soviet Union, more than 1,750 cases of beryllium occupational disease patients were registered. China has recorded nearly 100 cases of acute and chronic beryllium poisoning. Due to the long incubation period of beryllium poisoning, chronic cases are still increasing.
In order to reduce and prevent the occurrence of beryllium poisoning, some scholars in western countries proposed to carry out lymphocyte conversion test to screen out people who are sensitive to beryllium and may suffer from beryllium disease. In the former Soviet Union, it was stipulated that after ten years of beryllium work, they could be transferred from work. Because the mechanism of beryllium poisoning has not been clarified in medicine, there is no effective means for early diagnosis and treatment of beryllium occupational diseases. At present, only passive preventive measures can be taken. Therefore, beryllium poisoning and its protection are still one of the problems that beryllium metallurgy is difficult to solve.
Metabolism Of Beryllium In Living Organisms
Many scholars have done a lot of research on the absorption, distribution and excretion of beryllium in the body. For example, the metabolic process of beryllium in the living body has been studied by the isotope 7Be or 9Be tracer method. The research results show that when the body injects or inhales soluble beryllium, most beryllium is stored in the liver and bones, and a small part is stored in the spleen and kidney; when insoluble beryllium is inhaled, beryllium is mainly retained in the respiratory tract, lungs and lymph nodes, and the rest can be stored in the respiratory tract, lungs and lymph nodes. It is excreted in the urine, but at a slow rate for several years. When beryllium and its compounds are taken orally, beryllium ions can combine with protein or phosphorus to form compounds with little solubility, which are not absorbed by the stomach and intestines, and most of them are excreted in feces. Animal experiments show that the beryllium that enters the body from various routes is the most toxic by intravenous injection and the least by oral administration.
Because beryllium is a very chemically active element, it can replace magnesium, manganese or other trace elements necessary for the activity of the enzyme system. The effect of beryllium on enzyme activity has been identified. Beryllium has the greatest effect on the enzymes activated by magnesium ions. For example, beryllium can inhibit the activities of alkaline phosphatase, glucose phosphomutase, malate dehydrogenase and succinate dehydrogenase. When the beryllium entering the body is higher than the limit content, the activity of the above-mentioned enzymes is inhibited, the normal biochemical process in the body is destroyed, and it is reflected in cells, organs, the whole body and functions. However, a series of biochemical and pathological changes causing beryllium poisoning are still not fully understood.
Both beryllium and its salts are highly toxic, and their toxicity is not only related to dispersion and solubility, but also varies greatly with the type of beryllium compound and the way it enters the body. Generally, soluble beryllium is highly toxic, and insoluble beryllium is less toxic. It is the most toxic when immersed in blood, followed by respiratory tract, and the least toxic when immersed in digestive tract and skin. Beryllium oxide, beryllium fluoride, beryllium chloride, beryllium sulfate and beryllium nitrate are all toxic substances, while metal beryllium is relatively less toxic. After beryllium enters the human body, insoluble beryllium oxide is mainly stored in the lungs, which can Causes chemical bronchitis and pneumonia. Soluble beryllium compounds are mainly stored in bones, liver, kidneys and lymph nodes. Beryllium in lung and bone may be a carcinogen.
Beryllium compounds can also interact with plasma proteins to generate beryllium protein complexes, which cause tissue enlargement and changes, thereby causing granulomatous lesions of organs or tissues, and the rate of beryllium excretion from human tissues is extremely slow. The pathogenesis of acute beryllium poisoning and chronic beryllium poisoning may be different. The main manifestation of acute beryllium poisoning is the poisoning reaction of the body to stimulating substances, while chronic beryllium poisoning belongs to the scope of immune diseases and may be an allergic reaction.
The toxicity of beryllium and its compounds to the human body depends on many factors, such as the type of beryllium compound, the concentration of beryllium in the air, the exposure time, the sensitivity of the human body, repeated effects, atmospheric conditions, personal hygiene, etc. The most toxic soluble beryllium compounds are beryllium sulfate, beryllium chloride, beryllium oxyfluoride, beryllium fluoride, beryllium oxalate, beryllium acetate, and beryllium lactate.
Beryllium poisoning is a systemic disease in which beryllium and its compounds attack the lungs and can affect other organs. Clinically, it is divided into acute beryllium poisoning and chronic beryllium poisoning. Acute beryllium poisoning is caused by short-term inhalation of high concentrations of soluble beryllium salts, usually with respiratory and skin symptoms after several hours or days. Chronic beryllium poisoning is caused by long-term inhalation of low-concentration insoluble beryllium compounds. The incubation period is several months or years or even decades, and the onset is generally progressive.
- Acute poisoning: Short-term exposure to a large amount of beryllium dust or inhalation of soluble beryllium compounds can cause acute beryllium poisoning, with clinical manifestations of acute chemical pneumonia. Symptoms of acute beryllium poisoning include body aches, headache, fever, chest tightness and cough. After a few days to two weeks, symptoms such as shortness of breath, aggravated cough, chest pain, blood in the sputum, rapid heart rate and bruising occur, often accompanied by swelling and pain in the liver area, and even jaundice. Acute poisoning can also manifest as acute dermatitis and conjunctivitis, and exposure to large doses of beryllium may cause acute hepatitis. Patients with acute poisoning must immediately get rid of beryllium exposure, and take symptomatic treatment measures.
- Chronic poisoning: Exposure to a small amount of dust or smoke of beryllium and its compounds can cause chronic beryllium poisoning, with an incubation period of more than 20 years. The incidence of chronic beryllium poisoning is not completely determined by the inhalation dose under certain conditions, but is related to the individual’s sensitivity to beryllium. The United States has reported cases of poisoning of residents around beryllium factories, known as “near-neighbor disease.” The lungs of chronic poisoning patients form characteristic granulomas, called “beryllium lung” or beryllium disease, which are the most harmful to the human body. The main clinical manifestations are obvious weight loss, weakness, loss of appetite, often accompanied by chest pain, shortness of breath and cough, late stage complicated by pulmonary infection, spontaneous pneumothorax and chest heart disease, dyspnea, bruising, lower extremity edema and other signs of right heart failure. When beryllium goes under the skin, granulomas form deep in the skin. Granulomas persist for a long time and can only be removed surgically. In addition to lung and skin lesions in chronic beryllium poisoning, cytoplasmic, cellular infiltration, and fibrosis or granulomas may also occur in the liver, kidney, lymph nodes, skeletal muscle, myocardium, spleen, and pleura. The irreversible course of disease, long incubation period and obvious individual differences are the main features of chronic beryllium poisoning.Chronic beryllium poisoning cannot be diagnosed at an early stage. The main basis for the diagnosis of beryllium lung is: the exact history of beryllium exposure; positive X-ray changes with beryllium lung characteristics; obvious respiratory symptoms and systemic symptoms; urine beryllium and blood picture for reference. At present, there is no effective method for the treatment of beryllium disease. The United States and the United Kingdom have tested the use of beryllium complexing agents, such as sulfosalicylic acid, acetylacetone, gold tricarboxylic acid (A.T.A), etc. to treat beryllium disease. But the effect is not good. Hormone therapy in China has a significant effect on relieving the condition, but the condition worsens after the drug is stopped.
Analysis Of The Etiology Of Beryllium Poisoning
Due to its light weight, high strength, high temperature resistance, corrosion resistance, oxidation resistance, magnetic resistance and no sparks during processing, beryllium is widely used in nuclear energy, aerospace, national defense instruments, atomic energy, and electronics industries. Compounds (such as beryllium smelting beryllium alloy manufacturing, etc.) can cause beryllium poisoning by occupational exposure to beryllium dust or smoke.
Chronic beryllium poisoning is a delayed allergic disease with minimal exposure and individual susceptibility. Elemental beryllium is relatively stable. When beryllium ore is smelted to manufacture beryllium alloy, it can produce hinge and its compound dust, or soot. Its compounds include beryllium hydrogen oxide, beryllium oxide, beryllium fluoride, beryllium chloride, etc., mainly in the form of smoke or dust, Inhalation poisoning by respiratory tract.
Beryllium Poisoning Treatment
Acute beryllium poisoning should be treated symptomatically with bed rest and oxygen inhalation. Oral prednisone, symptoms improved, gradually reduce the dose, the course of treatment ranged from 2 to 4 weeks. Patients were followed up for 5 to 20 years. Patients with chronic beryllium poisoning are given oral prednisone, 30 to 45 days as a course of treatment, 2 courses of treatment per year for 2 to 5 years. Topical skin treatment, contact dermatitis with calamine lotion or corticosteroid ointment. The main treatment for beryllium ulcers is to wash the wound. Skin granulomas or subcutaneous nodules can be surgically removed.
The Safe Concentration Of Beryllium
In 1949, the Atomic Energy Commission (AEC) made the following regulations after investigating the poisoning of workers at beryllium plants and nearby residents:
- Calculated according to the average concentration of 8h working days, the concentration of beryllium in the air of beryllium production workshop shall not exceed 2ug/m³;
- Staff are not allowed to be exposed to air containing beryllium higher than 25ug/m³ at any time;
- The beryllium concentration in the air in the residential area near the beryllium factory shall not exceed 0.01ug/m³ on a monthly average.
These regulations have been recognized by the US Environmental Protection Agency, and Western countries have followed suit. The results show that the implementation of these regulations can basically control the occurrence of beryllium poisoning. In 1969, the World Health Organization (WHO) and the International Labor Organization (ILO) jointly stipulated that the safe concentration of beryllium and its compounds is 1 ~ 2ug/m³. The standard of the former Soviet Union is that the allowable concentration of beryllium in the production workshop is 1ug/m³. The Industrial Enterprise Design Hygiene Standard (GBJ3-73) formulated by China in 1973 stipulates that the average concentration of beryllium in the air in the work area should not exceed 1ug/m³, and that in the residential area should not exceed 0.01ug/m³. China also stipulates that the allowable concentration of beryllium in exhaust emissions is 15ug/m³.
In order to control beryllium poisoning, the environmental protection and industrial hygiene departments of some countries have also stipulated control indicators such as the allowable concentration of beryllium in wastewater, irrigation water, and surface water and surface contamination, but they have not been recognized and promoted by all countries in the world.
Environmental protection and industrial hygiene of beryllium production Due to the high toxicity of beryllium, the allowable concentration of beryllium in the air is extremely low. In order to meet safety standards, beryllium factories must establish complete protective facilities and protection systems. When building a beryllium plant and producing beryllium, the following nine aspects of environmental protection and industrial hygiene must be done well.
- The site of the beryllium factory should be selected in a remote area with few people, in the downwind direction and the drainage direction of the residential area. Do not set the site near a thermal power station and a large number of coal-fired boilers, because the coal dust contains a small amount of beryllium. It will increase the pollution of beryllium in the environment.
- The layout of the workshop shall adopt a three-zone system, namely living area, passing area and pollution area. Try to design the beryllium workshop as fully enclosed to prevent beryllium dust from spilling out. The inner surface of the workshop should be smooth to reduce dust accumulation and facilitate wet cleaning.
- To choose a production process that is conducive to protection: for example, when choosing a beryllium oxide production method, because the sulfate method to produce beryllium oxide is less toxic than the fluoride method to produce oxide plating, the former is often used.
- Use equipment with high degree of mechanization, automation and airtightness as much as possible to reduce the contact between people and beryllium-containing materials.
- Equipped with good ventilation facilities is the key to the protection of beryllium factories: for equipment that may overflow beryllium dust or beryllium smoke, reliable local exhaust should be adopted, and the exhaust vents or exhaust hoods should be carefully designed to ensure that All beryllium dust is discharged; the entire beryllium production plant should be fully ventilated, and the number of ventilations depends on the degree of pollution; the airflow should flow from the clean area to the polluted area, and a slight negative pressure should be maintained in the plant.
- There must be complete three-waste treatment facilities: all the discharged beryllium-containing gas must be carefully filtered and then discharged through the exhaust pipe; all the waste water should be concentrated in a special sewage treatment station, treated according to the specified process and qualified after inspection Re-discharge; waste residues are collected in special containers, and buried in special slag storage or abandoned mines on a regular basis.
- Personnel engaged in beryllium operations must first carry out safety education, strictly abide by the safety regulations and personal hygiene system of beryllium operations, and never allow items from polluted areas to be brought to clean areas or residential areas to prevent secondary pollution.
- Regularly monitor the concentration of beryllium in the air: the air in all parts of the workshop operation area and nearby residential areas should be regularly sampled and tested. If it is found that it exceeds the standard, the cause should be immediately investigated, and effective improvement measures should be taken to achieve the specified target. Beryllium production can be resumed.
- Strict medical supervision: The health check of the staff before employment. Anyone suffering from lung, heart, kidney, liver and skin diseases cannot engage in beryllium work; Those with symptoms such as fatigue, dry cough and chest tightness should have a comprehensive physical examination in time; be equipped with an industrial hygienist who is familiar with the production process of beryllium and the characteristics of beryllium poison, establish the health records of all employees, and conduct dynamic observation, which is indispensable for beryllium industrial hygiene made of.
The protection of beryllium poison is a comprehensive science, and any link cannot be ignored or made mistakes. Years of practice have shown that, despite paying a high price, the beryllium producing countries in the world can still better solve the protection problem of beryllium poisoning. For example, in the production of beryllium-containing substances, using industrial robots instead of manual operations can effectively prevent beryllium from contacting the human body, which is a good protection method.
The development of beryllium industry has been restricted by beryllium poison. With the increasingly strict requirements of human beings on environmental protection, and in recent years, some scholars believe that beryllium may be a carcinogen, therefore, the voice of further improving the protection and environmental protection standards of beryllium is getting louder. The U.S. Occupational Protection and Health Administration (OSHA) proposed in 1975 to reduce the average concentration of beryllium in the air from 2ug/m³ to 1ug/m³ and the instantaneous maximum concentration from 25ug/m³ to 5ug/m³. Due to a combination of economic and technical reasons, the above-mentioned standards have not been adopted. The protection problem of beryllium poison has not been completely solved, and it is still an important factor that plagues the development of beryllium industry. In the future, in addition to continuing to improve beryllium protection technology and further reducing the content of beryllium in the air, new breakthroughs in the medical mechanism, early diagnosis and treatment of beryllium poisoning are still to be made.
Beryllium has become one of the important additives in dentures due to its excellent wear resistance. Beryllium has a certain degree of radioactivity, and it is easy to form a variety of beryllium compounds under acidic and alkaline conditions. It has a long incubation period in the human body and will directly or indirectly affect human health. In particular, the beryllium ions absorbed by technicians and dentists during the grinding process will prevent blood circulation. When the accumulation is too high, gene mutation, carcinogenic lesions, and increased susceptibility to tumors may occur, and some patients may even develop allergic phenomena, 2003 In 2018, ADA made a decision to completely ban beryllium-containing metals. The use of beryllium-free metals to make dentures has been an industry requirement in developed countries in Europe and America.
With the development of materials science in recent years, beryllium-free teeth were born. Beryllium-free teeth replace beryllium with calcium-containing polyester organics, which are not only harmless to health, but also have better durability.