Asbestos Essay Research Paper Asbestos is the — страница 3

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fibers if disturbed. While it is often possible to suspect that a material or product contains asbestos by visual determination, actual determination can only be made by instrumental analysis. The EPA requires that the asbestos content of suspect materials be determined by collecting bulk samples and analyzing them by polarized light microscopy (PLM). The PLM technique determines both the percent and type of asbestos in the bulk material(Asbestos in Buildings 1-5). As reported in a survey recorded my the National Survey of Asbestos-Containing Friable Materials, rental residential buildings have the highest incidence of sprayed or troweeled-on asbestos containing friable material (2-6). After reviewing a report on asbestos in a local Procter and Gamble facility, the precautions

taken are very evident. The most common way for asbestos to enter the body is though breathing. Once inhaled, the asbestos fibers do not ever escape and it is thought that even small amounts can eventually produce lung cancer or mesothelioma, a lung-lining cancer. Another asbestos disease, asbestosis, requires much larger amounts of asbestos in the lungs than could be produced in a residence or a workplace that is not involved in the asbestos business. Asbestos cancers have a long latency period, 20-30 years, so that young people have a greater chance to be affected in their lifetime than older people (Pierce). Larger fibers usually get trapped in the nose hairs or in the mucous along the breathing passageways. However, some asbestos fibers are so small that they can bypass these

body defense mechanism and get deep into the lungs. Asbestos can also enter the digestive tract when you eat or smoke in a contaminated area. Asbestos does not pass through the skin. Asbestosis was the first clearly demonstrated adverse effect of asbestos in man. It is a nonmalignant fibrotic lung disease caused by inhalation of asbestos fibers. These fibers in the respiratory system reduce the ability of the lungs to extract sufficient oxygen from the air. It is associated with exposures to high concentrations of asbestos fibers (Pierce). Bronchogenic carcinoma is a malignant tumor which usually occurs in the lower lobes of the lungs. While asbestos exposure results in a small but significant risk of lung cancer, cigarette smoking in conjunction with asbestos exposure leads to a

total cancer risk which is many times greater than that from either asbestos exposure or smoking alone. Mesothelioma is a rare cancer of the linings of the chest and abdominal cavities. Exposures of only a few weeks duration to asbestos fibers have resulted in this disease. A unique feature of the disease is the long period, generally 20-30 years, between first exposure to asbestos and the appearance of a tumor. Asbestos is increasingly suspected to have a role in the development of cancers of the larynx and pharynx (Pierce). Once asbestos is determined to be present in a material, several options of dealing with the material are possible. The first option would be to leave the material as is and untouched. This is often the option of choice for non-friable materials, materials

which are in nonpublic areas and therefore only affect a few workers trained in asbestos hazards, and materials which are isolated from human contact. A second option is encapsulation, which means to enclose the material without removing it. The enclosure can consist of a constructed barrier, for instance, of finished drywall over a surface coating, or of painted canvas over pipe insulation. Alternatively, the encapsulation can be a sprayed polymer of two types: penetrating encapsulant, which soaks into the material it is sprayed on, and bridging encapsulant, which only seals the surface, like paint. Even though the release of fiber is minimized or eliminated with encapsulation, the asbestos is still present, and the potential for fiber release always exists. The third option is

removal, in which the asbestos-containing material is scraped off, chopped off or otherwise gotten rid and taken out of the building. Preparation of the building so as to prevent contamination of the premises is extensive and disposal of the material is expensive, so removal is the least economical of the three options. It has the advantage that the asbestos is for the most part gone, except those parts of the building that are inaccessible (Asbestos in Buildings 3-1). The only way to know if a product contains asbestos is to send a piece of the suspect material to a qualified laboratory, called a bulk sample. Only certain kinds of microscopes can be used to analyze the sample: a polarizing light microscope or an electron microscope (Pierce). The U.S. Environmental Protection