Asbestos Fibers and Other Elongate Mineral Particles: State of the ...

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Table 1. Definitions of general mineralogical terms 134 Glossary of Geology, 5th ed. [American Geological Institute 2005] Leake et al. [1997] NIOSH [1990a] Dictionary of Mining, Mineral, and Related Terms [U.S. Bureau of Mines 1996] [Note: Footnotes identify the Primary Source Citation for the definition] Term [crystal]: Said of a crystal that is needlelike in form. Acicular1 1. A mineral consisting of fine needlelike crystals, e.g., natrolite. 2. Slender needlelike crystal. 3. Refers to needlelike crystals. 2 Minerals in the amphibole group are widely distributed in the earth’s crust in many igneous or metamorphic rocks. In some instances, the mineral deposits contain sufficient quantities of the asbestiform minerals to be economically minable for commercial use. The minerals and mineral series of the amphibole group have variable compositions with extensive elemental substitutions. They are found in forms ranging from massive to fibrous. The most common commercially exploited asbestiform varieties of this mineralogical group include crocidolite, amosite, anthophyllite, tremolite, and actinolite. Crocidolite, amosite, and anthophyllite are selectively mined for commercial use, whereas tremolite and actinolite are most often found as a contaminant in other mined commodities such as talc and vermiculite. The amphiboles have good thermal and electrical insulation properties, and they have moderate to good resistance to acids. A mineral comprising a double silicate chain with the general VI IV formula AB2 C5 T8O22(OH) 2 with the components of the formula conventionally described as A, B, C, T and “OH” corresponding to the following crystallographic sites: A one site per formula unit; B two M4 sites per formula unit; C a composite of five sites made up of 2 M1, 2 M2 and 1 M3 sites per formula unit; T eight sites, in two sets of four, that need not be distinguished; “OH” two sites per formula unit. The ions considered normally to occupy these sites are in the following categories: (empty site) and K at A only; Na at A or B; Ca at B only; L-type ions: Mg, Fe2+ , Mn2+ , Li and rarer ions of similar size, at C or B; M-type ions: Al at C or T, Fe3+ and, more rarely Mn3+ , Cr3+ at C only; high-valency ions: Ti4+ at C or T, Zr4+ at C only, Si at T only; anions: OH, F, Cl, O at “OH”. M-type ions normally occupy M2 sites and so are normally limited to two of the five C sites. 1. A group of dark [sic] rock-forming ferromagnesian silicate minerals, closely related in crystal form and composition and having the general formula: A2-3B5(Si,Al) 8O22(OH) 2, where A = Mg, Fe2+ , Ca, or Na, and B = Mg, Fe2+ , Fe3+ , Li, Mn, or Al. It is characterized by a cross-linked double chain of tetrahedral with silicon:oxygen ratio of 4:11, by columnar or fibrous prismatic crystals, and by good prismatic cleavage in two directions parallel to the crystal faces and intersecting at angles of 56° and 124°; colors range from white to black. Most amphiboles crystallize in the monoclinic system, some in the orthorhombic. They constitute an abundant and widely distributed constituent in igneous and metamorphic rocks (some are wholly metamorphic), and they are analogous in chemical composition to the pyroxenes. 2. A mineral of the amphibole group, such as hornblende, anthophyllite, cummingtonite, tremolite, actinolite, riebeckite, glaucophane, arfvedsonite, etc. Amphibole A mineral group; characterized by double chains of silica tetrahedra having the composition A0-1B2Y5Z8O22(OH,F,Cl) , where (A = Ca,Na,K,Pb,B), (B = Ca,Fe,Li,Mg,Mn,Na), (Y = Al,Cr,Fe,Mg,Mn,Ti), and (Z = Al,Be,Si,Ti); in the orthorhombic or monoclinic crystal systems, including actinolite, anthophyllite, arfvedsonite, cummingtonite, hornblende, richterite, glaucophane, grunerite, anthophyllite, riebeckite, tremolite, and others. All display a diagnostic prismatic cleavage in two directions parallel to crystal faces and intersecting at angles of about 54° and 124°. Some members may be asbestiform. NIOSH CIB 62 • Asbestos See footnotes at end of table. (Continued)
Table 1. Definitions of general mineralogical terms (Continued) Glossary of Geology, 5th ed. [American Geological Institute 2005] Leake et al. [1997] NIOSH [1990a] Dictionary of Mining, Mineral, and Related Terms [U.S. Bureau of Mines 1996] [Note: Footnotes identify the Primary Source Citation for the definition] Term NIOSH CIB 62 • Asbestos Exceptions may occur to the above “normal” behavior. Four groups are classified depending on the occupancy of the B sites: Mg-Fe-Mn- Li group; calcic group; sodic-calcic group; and sodic group. Asbestiform amphiboles should be named according to their precise mineral name (when known) followed by the suffix—asbestos, e.g., anthophylliteasbestos, tremolite-asbestos. 3. A term sometimes used a synonym for hornblende. Etymol: Greek “amphibolos”, “ambiguous, doubtful”, in reference to its many varieties. Amphibole (Continued) A specific type of mineral fibrosity in which the growth is primarily in one dimension and the crystals form naturally as long, flexible fibers. Fibers can be found in bundles that can be easily separated into smaller bundles or ultimately into fibrils. Said of a mineral that is composed of separable fibers. Asbestiform1 1. Said of a mineral that is fibrous, i.e., like asbestos. See footnotes at end of table. (Continued) 135
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CURRENT INTELLIGENCE BULLETIN 62 As
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CURRENT INTELLIGENCE BULLETIN 62 As
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Foreword Asbestos has been a highly
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Executive Summary In the 1970s, NIO
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NIOSH recognizes that its 1990 desc
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of exposure to various types of EMP
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xii 2.9.3 Biopersistence and other
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xiv List of Figures Figure 1. U.S.
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xvi MAPK mitogen-activated protein
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xviii Brooke Mossman, PhD Universit
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controlled, even when exhaustive lo
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2 Overview of Current Issues 2.1 Ba
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juxtaposition or matrixed together,
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A further source of confusion comes
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Figure 2. Asbestos: Annual geometri
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Figure 3. Number of asbestosis deat
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at home by playing in areas where a
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physician from an occupational and
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of airborne asbestos fibers was fir
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which the deposits have been report
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with the most pronounced excess of
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A limitation of the epidemiological
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CI = 1.8-6.7) was noted in the earl
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exposure to commercial asbestos, an
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of these populations should be purs
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affect only a small number of obser
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exposed to fibers considerably long
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the extent to which the material ha
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or statistical power to permit a co
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capillaries, whereas insoluble part
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mechanisms and increase the rate of
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can penetrate their interior to pro
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A review for the EPA by an internat
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2.9.4.3.1 Reactive Oxygen Species A
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of different types of mineral parti
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secreted by mesothelial cells after
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direct oxidant production, exposure
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widths are greater for the prismati
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concluded that asbestos fibers
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crystal structure, and surface comp
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is calibrated appropriately for NIO
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is made of an area larger than a si
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data are needed to more fully asses
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70 III. Develop improved sampling a
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the current paradigm because their
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on the development of disease endpo
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esponse, and time-course data would
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In the second phase of cellular res
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80 • Investigate mechanisms of EM
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Research is needed to produce infor
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Page 119 and 120: 4 The Path Forward Developing an in
Page 121 and 122: surveillance investigations. By hav
Page 123 and 124: 5 References Aadchi S, Yoshida S, K
Page 125 and 126: Berman DW, Crump KS [2008b]. A meta
Page 127 and 128: mineral fiber number and epidemiolo
Page 129 and 130: the United States, 1968-81. J Natl
Page 131 and 132: Greim HA [2004]. Research needs to
Page 133 and 134: France: International Agency for Re
Page 135 and 136: millers in New York State. Arch Env
Page 137 and 138: Mandel J (mand0125@umn.edu) [2008].
Page 139 and 140: gpo.gov/2008/pdf/E8-3828.pdf]. Date
Page 141 and 142: Pneumoconioses to Digital Chest Rad
Page 143 and 144: Potter RM [2000]. Method for determ
Page 145 and 146: glass: pleural response in the rat
Page 147 and 148: Vianna NJ, Maslowsky J, Robert S, S
Page 149: Yano E, Wang Z, Wang X [2001]. Canc
Page 152 and 153: efficiency, regardless of sampler o
Page 156 and 157: Table 1. Definitions of general min
Page 166 and 167: Table 2. Definitions of specific mi
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