The Role Of Asbestos In The Environment
1. Introduction
The term asbestos is used to describe a group of six different fibrous minerals that occur naturally in the environment (Leake, et al., 1997). Asbestos minerals consist of thin, separable fibers that have a parallel arrangement (Ross & Nolan, 2003) and are widespread in the environment as they can occur as large natural deposits or as contaminants in other minerals (Kamp & Weitzman, 1999). Asbestos fibers are nonvolatile and insoluble, so their natural tendency is to settle out of air and water, and deposit in soil or sediment (Moyer et al., 1994). Some sufficiently small fibers can remain in suspension in both air and water and be transported long distances (Goodglick & Kane,1990). This method of travel significantly increases …show more content…
Physical and chemical properties such as fiber size, length, and iron content determine the level of asbestos toxicity. Asbestos minerals differ from each other in physical and chemical properties, and each mineral can exist in a wide range of fiber sizes (Goodglick & Kane, 1990). These differences between fiber type and, more importantly, fiber size are believed to be important determinants of the health risks posed by asbestos. Asbestos fibers are basically chemically inert, do not evaporate, dissolve, burn, or undergo significant reactions with most chemicals. In acid and neutral aqueous media, magnesium is lost from the outer brucite layer of chrysotile. Amphibole fibers are more resistant to acid attack and all varieties of asbestos are resistant to attack by alkalis (WHO, …show more content…
1 Classification
Asbestos fibrous silicate minerals are divided into two groups or classes, serpentine and amphibole. The silicate tetrahedron (SiO4) is the basic chemical unit of all silicate minerals (Hurlbut & Klein, 1977). The number of tetrahedra in the crystal structure and how they are arranged determine how a silicate mineral is classified (Hurlbut & Klein, 1977). Serpentine (chrysotile or white asbestos) is the most commonly used type of asbestos and amphiboles, which include crocidolite (blue asbestos), amosite (brown asbestos), tremolite, actinolite and anthophyllite (Roggli & Coin,
The term asbestos is used to describe a group of six different fibrous minerals that occur naturally in the environment (Leake, et al., 1997). Asbestos minerals consist of thin, separable fibers that have a parallel arrangement (Ross & Nolan, 2003) and are widespread in the environment as they can occur as large natural deposits or as contaminants in other minerals (Kamp & Weitzman, 1999). Asbestos fibers are nonvolatile and insoluble, so their natural tendency is to settle out of air and water, and deposit in soil or sediment (Moyer et al., 1994). Some sufficiently small fibers can remain in suspension in both air and water and be transported long distances (Goodglick & Kane,1990). This method of travel significantly increases …show more content…
Physical and chemical properties such as fiber size, length, and iron content determine the level of asbestos toxicity. Asbestos minerals differ from each other in physical and chemical properties, and each mineral can exist in a wide range of fiber sizes (Goodglick & Kane, 1990). These differences between fiber type and, more importantly, fiber size are believed to be important determinants of the health risks posed by asbestos. Asbestos fibers are basically chemically inert, do not evaporate, dissolve, burn, or undergo significant reactions with most chemicals. In acid and neutral aqueous media, magnesium is lost from the outer brucite layer of chrysotile. Amphibole fibers are more resistant to acid attack and all varieties of asbestos are resistant to attack by alkalis (WHO, …show more content…
1 Classification
Asbestos fibrous silicate minerals are divided into two groups or classes, serpentine and amphibole. The silicate tetrahedron (SiO4) is the basic chemical unit of all silicate minerals (Hurlbut & Klein, 1977). The number of tetrahedra in the crystal structure and how they are arranged determine how a silicate mineral is classified (Hurlbut & Klein, 1977). Serpentine (chrysotile or white asbestos) is the most commonly used type of asbestos and amphiboles, which include crocidolite (blue asbestos), amosite (brown asbestos), tremolite, actinolite and anthophyllite (Roggli & Coin,