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

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established precedence in applying it in RELs (e.g., the REL for metalworking fluid aerosols [NIOSH 1998]). Asbestos fibers currently are collected for measurement by standard sampling and analytical methods (e.g., NIOSH Method 7400 [NIOSH 1994a], in OSHA ID–160 [OSHA 1998], in Methods for the Determination of Hazardous Substances (MDHS) 39/4 [HSE 1995], and in ISO 8672 [ISO 1993]). In these methods, air samples are taken by means of a membrane filter housed in a cassette with a cowled sampling head. Early studies [Walton 1954] showed that the vertical cowl excludes some very coarse particles because of elutriation, but its selection characteristics should have little effect on the collection efficiency for asbestos fibers. However, when Chen and Baron [1996] evaluated the sampling cassette with a conductive cowl used in sampling for asbestos fibers, they found inlet deposition was higher in field measurements than predicted by models. Unlike the WHO [1997], NIOSH has not recommended an upper limit for width of asbestos fibers to be counted because airborne asbestos fibers typically have widths
fibers and other EMPs. In summary, accomplishing these goals is intended to (1) further elucidate the physicochemical properties that contribute to their pathogenicity; (2) improve existing analytical tools and develop new analytical tools for identifying and measuring exposures to EMPs with use of metrics that reflect the important determinants of toxicity (e.g., dimension and composition); (3) better define the nature and extent of occupational exposures to EMPs and their relationships to EMPrelated health outcomes among exposed worker populations; and (4) improve clinical tools for screening, diagnosis, secondary prevention, and treatment of EMP-related diseases. Results of much of the research to date (e.g., animal and human studies with asbestos and other EMPs) are readily available and should be considered in developing the research program, including the specification of minerals to be studied. Much of this evidence supports the important role of particle dimension as a determinant of lung deposition and retention and the concomitant role of particle composition and crystalline structure as a determinant of durability and biopersistence. Despite this body of research, several fundamental issues are not clearly understood, and a broad systematic approach to further toxicological and epidemiological research would help to reduce remaining uncertainties. Although long, thin asbestos fibers clearly cause respiratory disease, the role of unregulated short (i.e.,
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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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Page 65 and 66: can penetrate their interior to pro
Page 67 and 68: A review for the EPA by an internat
Page 69 and 70: 2.9.4.3.1 Reactive Oxygen Species A
Page 71 and 72: of different types of mineral parti
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Page 87: data are needed to more fully asses
Page 90 and 91: 70 III. Develop improved sampling a
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Page 96 and 97: esponse, and time-course data would
Page 98 and 99: In the second phase of cellular res
Page 100 and 101: 80 • Investigate mechanisms of EM
Page 102 and 103: Research is needed to produce infor
Page 104 and 105: periods that characterize manifesta
Page 106 and 107: children in tow, placing both sexes
Page 108 and 109: 88 • Develop, validate, and promo
Page 110 and 111: elevant, then an exposure assessmen
Page 112 and 113: ased on counts made by the current
Page 116 and 117: the mechanisms by which asbestos fi
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 154 and 155: Table 1. Definitions of general min
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Table 1. Definitions of general min
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Table 2. Definitions of specific mi
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safer • healthier • people tm D
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