What are the Dangers of Asbestos Exposure?

The quantity (concentration) and residence time of asbestos fibers in the environment reach a level that is harmful to human health. This phenomenon is called asbestos pollution. Asbestos has extraordinary flame-resistant and heat-resistant properties, mechanical tensile force equal to steel wire under the same size fiber, has the ability to be woven, has good compatibility with many chemicals, and is resistant to strong acids or alkalis. Therefore, it is used on a large scale in an extremely wide range of areas: textiles, building components, stoves, kilns, boilers for cooking and heating, irons and ironing boards, workbenches, fittings, refrigerators, firearms, engines And alternators, vehicles (brakes, clutches, washers), railway components, ships, aircraft, electrical equipment, etc. Invades the human body through the respiratory and digestive tracts

Asbestos pollution. Pollution caused by the amount (concentration) and residence time of asbestos fibers in the environment. Asbestos is a fibrous silicate mineral containing elements such as silicon, oxygen, hydrogen, sodium, magnesium, calcium, and iron. The main sources are natural processes such as soil erosion, weathering and volcanic eruptions, as well as man-made processes such as mining, processing, transportation of asbestos ore, and production and use of asbestos products. Asbestos is used in all materials. The brakes and clutch linings on motor vehicles contain 50% asbestos, and asbestos fibers (asbestos umbrellas) enter the air during use, causing air pollution. Using asbestos-containing filter materials to filter beverages and drugs, or using asbestos cement pipes as underground water pipes for tap water, will cause pollution of drinking water and food supplies. Many sources show that the air in major cities in the world is generally polluted by chrysotile. Long-term inhalation of asbestos fibers by production workers can cause asbestos lungs and induce mesothelioma, which has been identified as a carcinogen. The long-term inhalation of asbestos fibers by ordinary residents can increase the incidence of respiratory diseases. ^[1]

Chloro-asbestos polluting the environment mainly invades the body in the form of elementary fibers, which are crystalline and have sharp spikes that can penetrate the alveoli or the pleura and peritoneum. Continuous mechanical stimulation causes fibrosis of the local tissue, thickening of the pleura and peritoneum, and finally formation of cancer or mesothelioma. Some scholars believe that the carcinogenic effect of asbestos is produced by polycyclic aromatic hydrocarbons in asbestos fibers; others believe that it is related to the chemical properties of asbestos magnesium silicate. Which theory is more realistic is still inconclusive. ^[2]

Environmental asbestos pollution mainly comes from natural processes such as erosion and weathering of soil and rocks and volcanic eruptions, as well as man-made processes such as mining, processing, transportation of asbestos mines, and production and use of asbestos products.

A large amount of asbestos-containing material is sprayed on the surface of the structural steel frame of high-rise buildings. Asbestos-containing materials are used for sound insulation, insulation and decoration on the walls, ceilings and floors of many public buildings, causing air pollution inside the building. When blasting is used for demolition, a large amount of asbestos fibers or elementary fibers will be released into the surrounding atmosphere. Another example is that the brakes (brake shoes) and clutch linings on motor vehicles contain 50% asbestos. Their wear and tear also cause asbestos to pollute the environment. In addition, the use of asbestos-containing filters to filter beverages and drugs, as well as underground water pipes using asbestos cement pipes as tap water, can cause asbestos pollution. ^[2]

Asbestos belongs to the silicate category. In addition to asbestos in the environment, there are many silicates, so it is difficult to determine asbestos in the environment by chemical methods. The content of asbestos in the environment is very low. The asbestos in the atmosphere and water only accounts for several tens of thousands to several thousandths of the total suspended matter, so it cannot be determined by ordinary gravimetric methods. Electron microscopy is currently used for determination.

The chrysotile asbestos in the environment has an aspect ratio of greater than 3, is tubular, and has a capillary structure in the tube. The elementary fiber is magnified 10,000 to 20,000 times under an electron microscope, counted with its unique form, and the relationship between 1 fiber asbestos equals 1 million elementary fibers is converted into fiber per meter 3 to represent the asbestos content in the atmosphere. The content of asbestos in water is expressed as the number of asbestos fibers per liter of water.

Electron microscope measurement technology has many disadvantages, such as low accuracy (± 50%), complicated analysis steps and high cost. These disadvantages limit the extensive research on asbestos contamination. Many data prove that the air in large cities in the world is generally polluted by chrysotile asbestos. For example, in the United States, it is 0.1 to 100 fiber / m3; in the United Kingdom, it is 0 to 1.0 fiber / m3; in France, it is 0.2 to 1.5 fiber / m3; in the Netherlands, 0.1 100 fiber / m3 (asbestos industrial city); Belgium: 3 100 fiber / m3 (asbestos industrial city); Italy: 0.1 0.2 fiber / m3; China (Beijing): 0.04 1.06 fiber G / m3. There is little information on asbestos contamination in tap water. The average asbestos content in tap water in the United States is 1 million fibers per liter, up to 47 million fibers; the concentration of asbestos in tap water in Canada is 2 to 172.7 million fibers per liter. ^[2]

Nearly 10 years of experience in industrialized countries shows that it is technically possible to completely abandon asbestos, but there are still many obstacles for developing countries. Well, efforts must now be made to reduce and eliminate this serious risk at all times to protect contemporary and future generations; care must be provided to victims of asbestos-related diseases, which may have been caused by exposure to asbestos long ago ; Risk reduction measures must be developed, which are essential to address the issue of exposure to asbestos.

Asbestos pollution control measures

The construction of asbestos and asbestos processing plants is prohibited in cities, and high-efficiency dust removal devices should be added to existing plants to strengthen personal protection and regular medical examinations.

Establish emission standards and maximum allowable standards for asbestos. In the United States, the standard for asbestos in water is 0.05 micrograms per liter, and the states in Connecticut and New York state that the maximum allowable amount of asbestos in the atmosphere is 30 fibers per cubic meter (30-day average) and 27 fibers per cubic meter.

It is forbidden to spray refractory materials containing asbestos fibers. The US Environmental Protection Agency issued a ban in 1972.

It is strictly forbidden to dump asbestos garbage into rivers, lakes, seas and other waters.

Carry out research on asbestos carcinogenic mechanism and carcinogenesis to provide basis for formulating and preventing measures.

Action by Asbestos Contamination International

In 1977, the World Health Organization (WHO) stated that all asbestos formed, including serpentine asbestos, were carcinogenic according to the Asbestos Classification Group 1 of the International Cancer Institute (that is, substances known to cause carcinogenesis in humans).

In 1986, the International Labour Office, in Convention No. 162 adopted by the International Labour Organization (ILO), recommended that legislative authorities should make informed arrangements to "use other competent authorities that have been identified by scientists as harmless or less harmful" Materials, products or alternative technologies to replace asbestos, certain types of asbestos or products containing asbestos. "

In 1996, the World Health Organization stated that the use of safer materials that could replace fiber serpentine should be considered.

In 1998, the World Health Organization reaffirmed the carcinogenic effects of serpentine asbestos, particularly the risk of mesothelioma, continued to call for alternatives, and drew attention to the wide spread of this risk among a large number of workers.

The World Health Organization has also stated that there is no threshold established below which asbestos dust does not pose a cancer risk.

Asbestos pollution prevention status

Many countries have opted for a total ban on the use of this hazardous substance and have decided to stop this risk from spreading across their territories in order to protect future generations. These countries include most EU member states (all member states must ban all asbestos use by 2005) and an increasing number of other countries (Iceland, Norway, Switzerland, New Zealand, Czech Republic, Chile, Peru). Other countries are examining the dangers of asbestos, such as Australia and Brazil.

Some countries have greatly reduced the scope of application of asbestos, limiting this application to very few cases (especially asbestos cement), they claim that they have implemented strict enough regulations to protect workers' health (such as the United States, Canada) and can Control the method used when handling asbestos.

And some activities with serious risks of asbestos exposure (such as shipbreaking) are often carried out in countries with the lowest labor costs, which is an important economic undertaking for these countries.

In many countries, associations have been established to organize victims' claims and safeguard their interests, especially to improve the financial situation of their care. This situation can occur even when the employer does not take appropriate protective measures, even in the context of obvious risks and the protections required by national legislation, so these associations often recommend that victims take individual legal action against employers; Increasing numbers of cases have also targeted the state, claiming that the state has been too slow to act on regulations protecting workers' health or protecting the public from asbestos.

Worldwide efforts to ban asbestos continue, however, producers and consumers of chrysotile asbestos products are struggling to offset their efforts. All nations have to face this global threat, and each nation has a responsibility to face the health disasters in its territory that have occurred in the past and present use of this dangerous substance; each nation has a moral obligation to deal with itself Own asbestos and bear responsibility for its consequences. ^[2]