What Is Pneumoconiosis and Is It Work-related?
AsbestosisAsbestosis is caused by inhalation of asbestos dust. Asbestos is a group of silicate minerals that naturally exist as bundles of treads that can be separated into thin, durable fibers. Because the fibers having many desirable physical properties, such as being resistant to heat, fire, and chemicals as well as the fact that they do not conduct electricity, asbestos has been, – and still is – widely used, in many industrial contexts. Asbestos is built up by bundles of long, durable treads. When mechanically treated, the treads spilt into long, thin fibers. The thinnest of these are respirable. Because asbestos is very durable and chemically resistant, the lung clearing mechanisms do not work effectively on the inhaled fibers. Thus an exposed person essentially ends up with a chronic exposure situation once the fibers are first inhaled. © University of Bergen
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Occupational Health in Developing Countries
SilicosisSilicosis is another kind of pnemoconiosis. It is caused by inhalation of crystalline silica, and it is the most common work-related lung disease worldwide. Silicosis is a progressive condition, characterized by coughing and shortness of breath and results in permanent lung damage. Acute silicosis develops after exposure to high concentrations of respirable crystalline silica, and produces symptoms within a few weeks to a few years after the initial exposure. This condition is rare, and has a very poor prognosis. Chronic silicosis develops slowly, usually appearing 10 to 30 years after the first exposure. The silicosis diagnosis is based on chest X-rays or CT findings and a history of exposure to crystalline silica. There is no cure for silicosis. Sandstone, which mostly is composed of crystalline silica, is relatively soft, making it easy to carve.
© G. Tjalvin The compound silica (SiO2) is formed from silicon (Si) and oxygen (O) atoms, which are the two most abundant elements in the earth’s crust. Hence, silica is a very abundant mineral. The mass of earth’s crust is 59 % silica, and it is the main constituent of more than 95 % of the known types of rocks. Silica exists in crystalline and amorphous varieties. It is the crystalline form that causes silicosis. This form is even known to be carcinogenous. Any occupation that disturbs the earth’s crust, or involves processing or using silica-containing sand, rock or ores has potential risk for silicosis. Silica-containing sand is used in buildings and roads in the form of Portland cement, concrete, and mortar. Silica sand is also used by sandblasters, for instance in the metal and the textile industries. Silica is also found in foundry molds; in the manufacture of glass, ceramics, and ferrosilicon as well as in gemstones. Miners are exposed to crystalline silica.© Christophe Meneboeuf, via Wikimedia Commons CC BY-SA 3.0 In the textile industry, sandblasting using silica-containing sand gives blue jeans a trendy, worn look. Denim sandblasting workers have been reported as exhibiting an acute and very aggressive form of silicosis. © Colourbox
Coal worker’s pneumoconiosis (CWP)Coal worker’s pneumoconiosis (CWP) or ‘black lung’ is a third type of pneumoconiosis. It is caused by inhalation of coal dust. Inhaled coal dust becomes a problem when the body’s natural mechanisms for defending against and processing the dust becomes overwhelmed and, subsequently, over-reactive. The result is inflammation, fibrosis and in the worst cases, necrosis of the lung tissue. Simple CWP usually causes few symptoms, but a cough may develop that can be chronic and problematic in patients even after they leave the workplace. Some patients with simple CWP develop progressive massive fibrosis, which is characterized by progressive dyspnea, and occasionally, they may cough up black sputum. This condition often progresses to pulmonary hypertension with right ventricular and respiratory failure. As for the other types of pneumoconiosis, the exposure levels have to be quite high over a long period of time, typically more than 20 years, to develop CWP. CWP is diagnosed based on chest X-ray or CT findings, and a history of work in coal mines. There is no cure for coal worker’s pneumoconiosis. Coal mine workers. © Simon Mamuya
Occupational Health in Developing Countries
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