Measurement of elongate mineral particles: What we should measure and how do we do it?

Chatfield, Eric

doi:10.1016/j.taap.2018.08.010

Cited by 16 publications

(6 citation statements)

References 19 publications

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“…Under ASTM D7200‐12, the 629 countable amphibole EMPs were essentially divided into two groups: Group 1, comprised of 218 EMPs with width < 1 μm (median width, 0.7 μm, and median AR, 10.8:1) and Group 2, comprised of 411 EMPs with width ≥1 μm (median width, 1.5 μm, and median AR, 4.8) (Table II ). The ASTM D7200‐12 groupings more closely match those proposed by Chatfield ( 2010 , 2018 ) for discriminating potentially asbestiform minerals (length >5 μm, width <1.5 μm, AR ≥20:1) from likely cleavage fragments that meet countable EMP criteria (length >5 μm, and AR <20:1). In the former group, EMPs had median width of 0.3 μm and in the latter group, EMPs had median width of 1.3 μm (Table II ).…”

Section: Resultssupporting

confidence: 78%

“…OSHA ( 1992 ) described cleavage fragments formed during the comminution of minerals as typically showing AR <20:1. As a simplified approach, Chatfield ( 2010 , 2018 ) proposed identifying potentially asbestiform EMPs using TEM and counting EMPs with AR ≥20:1 and width <1.5 μm. The American Society for Testing and Materials (ASTM) developed the Standard Practice for Sampling and Counting Airborne Fibers, including Asbestos Fibers, in Mines and Quarries, by Phase Contrast Microscopy and Transmission Electron Microscopy (D7200‐06) to identify and discriminate countable EMPs (length >5 μm using NIOSH 7400 “A” rules) that are likely to be asbestiform from EMPs of similar dimensions that are likely to be nonasbestiform cleavage fragments or prismatic crystals.…”

Section: Data Sources and Methodsmentioning

confidence: 99%

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Integration of Evidence on Community Cancer Risks from Elongate Mineral Particles in Silver Bay, Minnesota

Dell¹,

Gallagher²,

Yost³

et al. 2021

Risk Analysis

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The potential for cancer‐related risks to community members from ambient exposure to elongate mineral particles (EMPs) in taconite processing has not been formally evaluated. We evaluated 926 ambient air samples including 12,928 EMPs (particle structures with length‐to‐width ratio ≥3:1) collected over 26 years near a taconite processing facility in Silver Bay, Minnesota. Eighty‐two percent of EMPs were ≤3 μm in length and 97% of EMPs had an average aspect ratio <20:1. A total of 935 (7.3%) EMPs had length >5 μm and AR ≥3:1. Average ambient concentration of NIOSH countable amphibole EMPs over all years was 0.000387 EMPs per cubic centimeter (EMP/cm3). Of 12,765 nonchrysotile EMPs, the number of amphiboles with length and width dimensions that correlate best with asbestos‐related carcinogenicity ranged from four (0.03%) to 13 (0.1%) and the associated ambient amphibole air concentrations ranged from 0.000003 to 0.000007 EMP/cm3. After 65 years of taconite processing in Silver Bay, evidence of an increased risk of mesothelioma and lung cancer in community members who did not work in the taconite industry is lacking. The absence of an increased risk of asbestos‐related cancer in the Silver Bay community is coherent with supporting evidence from epidemiological and toxicological studies, as well as ambient exposure data and lake sediment data collected in Minnesota Iron Range communities. Collectively, the data provide consistent evidence that nonasbestiform amphibole minerals lack the carcinogenic potential exhibited by amphibole asbestos.

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Section: Resultssupporting

confidence: 78%

Section: Data Sources and Methodsmentioning

confidence: 99%

Integration of Evidence on Community Cancer Risks from Elongate Mineral Particles in Silver Bay, Minnesota

Dell¹,

Gallagher²,

Yost³

et al. 2021

Risk Analysis

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“…Although the exact mechanisms for the carcinogenic response caused by inhaled asbestos particles and other elongate mineral particles (e.g., fibrous fluoro-edenite and fibrous erionite) are not fully understood, the available evidence supports that harm may be caused by both long-term and short-term exposure [ 7 , 8 ]. EMPs include asbestiform (non-asbestos classified minerals which are similar to asbestos in terms of morphology and properties [ 4 , 9 ]) and non-asbestiform minerals as well as cleavage fragments of non-asbestiform variants of asbestos minerals [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

Asbestos and Other Hazardous Fibrous Minerals: Potential Exposure Pathways and Associated Health Risks

Berry

Belluso

Vigliaturo

et al. 2022

IJERPH

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There are six elongate mineral particles (EMPs) corresponding to specific dimensional and morphological criteria, known as asbestos. Responsible for health issues including asbestosis, and malignant mesothelioma, asbestos has been well researched. Despite this, significant exposure continues to occur throughout the world, potentially affecting 125 million people in the workplace and causing thousands of deaths annually from exposure in homes. However, there are other EMPS, such as fibrous/asbestiform erionite, that are classified as carcinogens and have been linked to cancers in areas where it has been incorporated into local building materials or released into the environment through earthmoving activities. Erionite is a more potent carcinogen than asbestos but as it is seldom used for commercial purposes, exposure pathways have been less well studied. Despite the apparent structural and chemical similarities between asbestos and fibrous erionite, their health risks and exposure pathways are quite different. This article examines the hazards presented by EMPs with a particular focus on fibrous erionite. It includes a discussion of the global locations of erionite and similar hazardous minerals, a comparison of the multiple exposure pathways for asbestos and fibrous erionite, a brief discussion of the confusing nomenclature associated with EMPs, and considerations of increasing global mesothelioma cases.

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Section: Introductionmentioning

confidence: 99%

“…Many authors propose more rigorous dimensional counting criteria be implemented to better discriminate asbestiform fibres from potentially non-toxic cleavage fragments [ 35 , 36 , 37 ]. Various metrics have been suggested including particles with a L > 10 μm, D < 0.4 μm, AR > 25:1 [ 35 ], D < 1.5 μm, AR > 20:1 [ 36 ] or AR ≥ 5:1 [ 37 , 38 ] only be considered as countable. Western Australia (WA) previously used the more stringent dimensional parameters of L ˃ 5 µm and D ≤ 1 µm as counting criteria in the Mines Safety and Inspection Regulations 1995 (WA) (s.9.33.3) [ 39 ].…”

Section: Introductionmentioning

confidence: 99%

Pathogenic Potential of Respirable Spodumene Cleavage Fragments following Application of Regulatory Counting Criteria for Asbestiform Fibres

Cross

Reed

Davidson

et al. 2022

IJERPH

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Health risks from exposure to lithium-bearing spodumene cleavage fragments are unknown. While asbestiform fibres can lead to fibrosis, mesothelioma and lung cancer, controversy remains whether non-asbestiform cleavage fragments, having equivalent dimensions, elicit similar pathologic responses. The mineralogy of respirable particles from two alpha (α)-spodumene concentrate grades (chemical and technical) were characterised using semi-quantitative X-ray diffraction (XRD). Particles were measured using scanning electron microscopy (SEM) and the dimensions (length [L], diameter [D], aspect ratio [AR]) applied to regulatory counting criteria for asbestiform fibres. Application of the current World Health Organization (WHO) and National Occupational Health and Safety Commission (NOHSC) counting criteria, L ˃ 5 µm, D ˂ 3 µm, AR ˃ 3:1, to 10 SEM images of each grade identified 47 countable particles in the chemical and 37 in the technical concentrate test samples. Of these particles, 17 and 16 in the chemical and technical test samples, respectively, satisfied the more rigorous, previously used Mines Safety and Inspection Regulations 1995 (Western Australia [WA]) criteria, L ˃ 5 µm and D ≤ 1 µm. The majority of the countable particles were consistent with α-spodumene cleavage fragments. These results suggest elongated α-spodumene particles may pose a health risk. It is recommended the precautionary principle be applied to respirable α-spodumene particles and the identification and control of dust hazards in spodumene extraction, handling and processing industries be implemented.

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Measurement of elongate mineral particles: What we should measure and how do we do it?

Cited by 16 publications

References 19 publications

Integration of Evidence on Community Cancer Risks from Elongate Mineral Particles in Silver Bay, Minnesota

Integration of Evidence on Community Cancer Risks from Elongate Mineral Particles in Silver Bay, Minnesota

Asbestos and Other Hazardous Fibrous Minerals: Potential Exposure Pathways and Associated Health Risks

Pathogenic Potential of Respirable Spodumene Cleavage Fragments following Application of Regulatory Counting Criteria for Asbestiform Fibres

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