Research

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19 pages, 1827 KiB

Open AccessArticle

The Potential Health Costs of PM₁₀ Impacts on a Gold Mine Village, during Company Liquidation: An Analysis of 2013–2017

by Mbalenhle Mpanza, Elhadi Adam and Raeesa Moolla

Minerals 2022, 12(2), 169; https://doi.org/10.3390/min12020169 - 28 Jan 2022

Cited by 1 | Viewed by 2167

Windblown dust from tailings storage facilities (TSFs), particularly in towns with liquidated mining companies, exacerbate air pollution. Companies of suddenly closed mine operations evade the responsibility of environmental and socio-economic care required by law. It is common for suddenly closed mines to have [...] Read more.

Windblown dust from tailings storage facilities (TSFs), particularly in towns with liquidated mining companies, exacerbate air pollution. Companies of suddenly closed mine operations evade the responsibility of environmental and socio-economic care required by law. It is common for suddenly closed mines to have poorly rehabilitated TSFs which become a significant source of pollution by dust for the surrounding communities. There is strong evidence that acute exposure to high levels of air pollutants causes significant mortality and morbidity. However, very few studies have estimated the externalities of PM₁₀ emanating from gold TSFs especially when a mine closes suddenly owing to company liquidation. By exploring the externalities of PM₁₀ arising from wind erosion of suspended particulate matter from TSFs, this study fills an existing gap in the literature. A ‘bottom-up’ approach was implemented in this study following the External Energy (ExternE) project, and a gold mine operation that was liquidated between 2013 and 2017, was used as the case study. In this study, the externality of PM₁₀ estimated was the cost of illness focusing specifically on respiratory-related illnesses. The results showed that the estimated cost of illness associated with PM₁₀ inhalation was a total of R 5,560,022 including assessments of both neighboring Wedela and the Gold mine village based on the threshold concentration set by the South African National Ambient Air Quality Standards (NAAQS) guideline and R 66,092,760 when considering the Fund for Research into Industrial Development Growth Equity (FRIDGE), Airshed and Infotox. Thus, it was concluded that air pollution by windblown dust from partially rehabilitated TSFs has the potential to significantly affect surrounding mining communities’ socio-economic status through poor health and the costs thereof. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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18 pages, 3003 KiB

Open AccessArticle

Dust Characterization and Its Potential Impact during the 2014–2015 Fogo Volcano Eruption (Cape Verde)

by Carla Candeias, Paula Freire Ávila, Célia Alves, Carla Gama, Cristina Sequeira, Eduardo Ferreira da Silva and Fernando Rocha

Minerals 2021, 11(11), 1275; https://doi.org/10.3390/min11111275 - 17 Nov 2021

Cited by 3 | Viewed by 1953

Abstract

Fogo (Fogo Island) is the youngest and most active volcano of Cape Verde. The last eruption occurred in 2014–2015. Aiming to assess the dust sources that impacted the air quality during the present study period, fresh lava samples were collected, while Saharan dust [...] Read more.

Fogo (Fogo Island) is the youngest and most active volcano of Cape Verde. The last eruption occurred in 2014–2015. Aiming to assess the dust sources that impacted the air quality during the present study period, fresh lava samples were collected, while Saharan dust intrusions and transport were modeled. Rooftop dust was also collected on the island dwellings and a mineralogical and chemical characterization was undertaken. Air quality monitors were used to obtain concentrations of atmospheric particulate matter (PM) and gaseous pollutants. The mineralogical constitution was assessed by XRD and Electron Microprobe. The pseudototal chemical concentration was performed by XRF, ICP-MS and SEM; the latter includes particles morphology. During the study, WRF-CHIMERE results showed the intrusion of desert dust which affected the air quality. Lava was classified as tephritic to basanitic, with high potassium content. The Pollution Load Index for rooftop dust was >1 in all samples, suggesting an enrichment. Higher values were found in dust size fraction <63 µm, with contamination factor pointing to high enrichment of As, Ni and Pb, and very high enrichment of Cd. The non-carcinogenic hazard estimated for children suggested that health problems may arise. The carcinogenic risk was above the target risk, mostly due to As > Pb > Co. Ingestion was the main exposure route. PM₁₀ concentrations exceeded the 24-h mean of 50 µg/m³ recommended by WHO. Nevertheless, TVOCs displayed levels lower than guidelines. The highest levels of CO₂ were recorded in more populated villages and farthest from the volcano. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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45 pages, 13998 KiB

Open AccessArticle

Screening Coarse Airborne Dust for Lead-Rich Phase Occurrence during Characterisation of Particle Mineralogy, Chemistry and Provenance: Application to Deposits in the Vicinity of an Integrated Steelworks

by James Small, Corrie van Hoek, Frank van der Does, Anne-Bart Seinen, Stefan Melzer, Peter Tromp and Sieger van der Laan

Minerals 2021, 11(9), 929; https://doi.org/10.3390/min11090929 - 27 Aug 2021

Viewed by 1845

Abstract

A method has been developed to screen large numbers (~10³–10⁴ per sample) of coarse airborne dust particles for the occurrence of Pb-rich phases, together with quantification of the particles’ mineralogy, chemistry, and inferred provenance. Using SEM-EDS spectral imaging (SI) at [...] Read more.

A method has been developed to screen large numbers (~10³–10⁴ per sample) of coarse airborne dust particles for the occurrence of Pb-rich phases, together with quantification of the particles’ mineralogy, chemistry, and inferred provenance. Using SEM-EDS spectral imaging (SI) at 15 kV, and processing with the custom software PARC, screening of individual SI pixels is performed for Pb at the concentration level of ~10% at a length-scale of ~1 µm. The issue of overlapping Pb-Mα and S-Kα signal is resolved by exploiting peak shape criteria. The general efficacy of the method is demonstrated on a set of NIST particulate dust standard reference materials (SRMs 1649b, 2580, 2584 and 2587) with variable total Pb concentrations, and applied to a set of 31 dust samples taken in the municipalities surrounding the integrated steelworks of Tata Steel in IJmuiden, the Netherlands. The total abundances of Pb-rich pixels in the samples range from none to 0.094 area % of the (total) particle surfaces. Overall, out of ca. 92k screened particles, Pb was found in six discrete Pb-phase dominated particles and, more commonly, as superficial sub-particles (sub-micron to 10 µm) adhering to coarser particles of diverse and Pb-unrelated provenance. No relationship is apparent between the samples’ Pb-rich pixel abundance and their overall composition in terms of particle provenance. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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12 pages, 2325 KiB

Open AccessArticle

Direct-on-Filter FTIR Spectroscopy to Estimate Calcite as A Proxy for Limestone ‘Rock Dust’ in Respirable Coal Mine Dust Samples

by Nishan Pokhrel, Cigdem Keles, Lizeth Jaramillo, Eleftheria Agioutanti and Emily Sarver

Minerals 2021, 11(9), 922; https://doi.org/10.3390/min11090922 - 25 Aug 2021

Cited by 6 | Viewed by 1878

Abstract

Application of fine, inert ‘rock dust’ (RD) to the surfaces in underground coal mines is a common method for mitigating coal dust explosion hazards. However, due to its size, RD has the potential to contribute to the respirable coal mine dust (RCMD) concentration. [...] Read more.

Application of fine, inert ‘rock dust’ (RD) to the surfaces in underground coal mines is a common method for mitigating coal dust explosion hazards. However, due to its size, RD has the potential to contribute to the respirable coal mine dust (RCMD) concentration. Though the RD component of RCMD does not appear to pose the sort of health hazards associated with other components such as crystalline silica, understanding its relative abundance may be quite helpful for evaluating and controlling primary dust sources. Given that RD products are frequently comprised of high-purity limestone (i.e., primarily calcite mineral), calcite may serve as a suitable proxy for measuring RD. To estimate the mass percentage of calcite in RCMD samples, this study demonstrates the successful application of direct-on-filter (DOF) Fourier-transform infrared (FTIR) spectroscopy. Incidentally, DOF FTIR has been the focus of recent efforts to enable rapid measurement of crystalline silica in RCMD. Concurrent measurement of other constituents such as calcite is thus a logical next step, which can allow a broader interpretation of dust composition and source contributions. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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15 pages, 4134 KiB

Open AccessArticle

Demonstration of Optical Microscopy and Image Processing to Classify Respirable Coal Mine Dust Particles

by Nestor Santa, Cigdem Keles, J. R. Saylor and Emily Sarver

Minerals 2021, 11(8), 838; https://doi.org/10.3390/min11080838 - 02 Aug 2021

Cited by 5 | Viewed by 2474

Abstract

Respirable coal mine dust represents a serious health hazard for miners. Monitoring methods are needed that enable fractionation of dust into its primary components, and that do so in real time. Near the production face, a simple capability to monitor the coal versus [...] Read more.

Respirable coal mine dust represents a serious health hazard for miners. Monitoring methods are needed that enable fractionation of dust into its primary components, and that do so in real time. Near the production face, a simple capability to monitor the coal versus mineral dust fractions would be highly valuable for tracking changes in dust sources—and supporting timely responses in terms of dust controls or other interventions to reduce exposures. In this work, the premise of dust monitoring with polarized light microscopy was explored. Using images of coal and representative mineral particles (kaolinite, crystalline silica, and limestone rock dust), a model was built to exploit birefringence of the mineral particles and effectively separate them from the coal. The model showed >95% accuracy on a test dataset with known particles. For composite samples containing both coal and minerals, the model also showed a very good agreement with results from the scanning electron microscopy classification, which was used as a reference method. Results could further the concept of a “cell phone microscope” type monitor for semi-continuous measurements in coal mines. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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19 pages, 2743 KiB

Open AccessArticle

Health Risks and Source Analysis of Heavy Metal Pollution from Dust in Tianshui, China

by Bo Tan, Hongwei Wang, Xinmin Wang, Chen Ma, Jing Zhou and Xinyan Dai

Minerals 2021, 11(5), 502; https://doi.org/10.3390/min11050502 - 09 May 2021

Cited by 17 | Viewed by 2355

Abstract

The purpose of this study is to explore the degree and spatial distribution of dust heavy metal pollution in Tianshui City, the health risks, and the sources of heavy metals. The geoaccumulation index and health risk assessment are used to study pollution levels [...] Read more.

The purpose of this study is to explore the degree and spatial distribution of dust heavy metal pollution in Tianshui City, the health risks, and the sources of heavy metals. The geoaccumulation index and health risk assessment are used to study pollution levels and human health risks, and Cu, Zn, and Pb pollution are found to be serious. The total exposure of children to dust and heavy metals is 8.329 × 10⁻³ mg·kg⁻¹·d⁻¹, which is 4.66 times that of adults. The effect of carcinogenic heavy metal exposure is more significant for adults than for children. The total non-carcinogenic risk quotient to children via multiple pathways is 2.1690, which is higher than that of adults. Children’s Pb non-carcinogenic risk quotient is 4.79 times that of adults, and children are more sensitive than adults to the health risks of Pb pollution. The GeoDetector and Unmix 6.0 models are used for source analysis, revealing that Zn, Pb, and As pollution originate primarily from urban transportation systems, V is sourced from soil-forming parent materials, and Mn, Ni, Cu, and Co arise from mixed sources. Therefore, the treatment of heavy metal pollution in cities needs to focus more on the urban transportation system. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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10 pages, 4152 KiB

Open AccessArticle

Characterization of Particulates from Australian Underground Coal Mines

by Nikky LaBranche, Cigdem Keles, Emily Sarver, Kelly Johnstone and David Cliff

Minerals 2021, 11(5), 447; https://doi.org/10.3390/min11050447 - 23 Apr 2021

Cited by 14 | Viewed by 2634

Abstract

The re-identification of coal workers’ pneumoconiosis in Queensland in 2015 has prompted improvements in exposure monitoring and health surveillance in Australia. The potential consequences of excessive exposure to respirable dust may depend upon the size, shape and mineralogical classes of the dust. Technology [...] Read more.

The re-identification of coal workers’ pneumoconiosis in Queensland in 2015 has prompted improvements in exposure monitoring and health surveillance in Australia. The potential consequences of excessive exposure to respirable dust may depend upon the size, shape and mineralogical classes of the dust. Technology has now advanced to the point that the dust characteristics can be explored in detail. This research collected respirable dust samples from four operating underground coal mines in Australia for characterization analysis using scanning electron microscopy (SEM) with energy dispersive X-ray (EDX). The research found multiple mineralogical classes present with their own particle size distributions. The variation between mines appears to have had a larger effect on particle size distribution than the differences in mining processes within individual mines. This may be due to variations in the geologic conditions, seam variation or mining conditions. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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24 pages, 7668 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Complexity of Respirable Dust Found in Mining Operations as Characterized by X-ray Diffraction and FTIR Analysis

by Rachel L. T. Walker, Emanuele Cauda, Lauren Chubb, Patrick Krebs, Robert Stach, Boris Mizaikoff and Cliff Johnston

Minerals 2021, 11(4), 383; https://doi.org/10.3390/min11040383 - 02 Apr 2021

Cited by 8 | Viewed by 2594

Abstract

The mineralogical complexity of mine dust complicates exposure monitoring methods for occupational, respirable hazards. Improved understanding of the variability in respirable dust characteristics, e.g., mineral phase occurrence and composition, is required to advance on-site monitoring techniques that can be applied across diverse mining [...] Read more.

The mineralogical complexity of mine dust complicates exposure monitoring methods for occupational, respirable hazards. Improved understanding of the variability in respirable dust characteristics, e.g., mineral phase occurrence and composition, is required to advance on-site monitoring techniques that can be applied across diverse mining sectors. Principal components analysis (PCA) models were applied separately to XRD and FTIR datasets collected on 130 respirable dust samples from seven mining commodities to explore similarities and differences among the samples. Findings from both PCA models classified limestone, iron, and granite mine samples via their analytical responses. However, the results also cautioned that respirable samples from these commodities may not always fit patterns observed within the model. For example, one unique sample collected in a limestone mine contained no carbonate minerals. Future predictive quantification models should account for unique samples. Differences between gold and copper mine dust samples were difficult to observe. Further investigation suggested that the key to their differentiation by FTIR may lie in the characterization of clays. The results presented in this study provide foundational information for guiding the development of quantification models for respirable mineral hazards in the mining industry. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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9 pages, 2197 KiB

Open AccessArticle

Laboratory Determination of Coal Dust Cleaning Efficacy of a Fibrous Filter for Flooded-Bed Dust Scrubber

by Neeraj Gupta, Ashish Ranjan Kumar and Steven Schafrik

Minerals 2021, 11(3), 295; https://doi.org/10.3390/min11030295 - 11 Mar 2021

Cited by 7 | Viewed by 2279

Abstract

Fibrous-type dust filters are used in flooded-bed dust scrubbers to capture dust from underground room and pillar mining atmospheres. They have 10–30 layers of finely woven strands that trap particles through the interception and impaction process. A full-cone water spray is installed upstream [...] Read more.

Fibrous-type dust filters are used in flooded-bed dust scrubbers to capture dust from underground room and pillar mining atmospheres. They have 10–30 layers of finely woven strands that trap particles through the interception and impaction process. A full-cone water spray is installed upstream of the filter, which floods the screen. A scrubber’s efficacy is usually measured and reported in terms of reduction in gravimetric dust concentration at a known location in a mine. This paper reports the particle-size-dependent dust removal efficiency of a fibrous filter obtained from an instrumented test-set up. A variable frequency drive and an inline flow control knob were used to control the airflow through the filter and water flow onto the filter. Optical particle counting of coal dust particles upstream and downstream was carried out to determine the cleaning efficacy. Experiments showed an increase in cleaning efficiency for all the dust particles with their size. A progressive decrease in dust concentration downstream of the filter with an increase in water flow through the nozzle affirmed the capture of dust particles by water sprays. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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13 pages, 3015 KiB

Open AccessArticle

Characterization of Particle Size and Composition of Respirable Coal Mine Dust

by Lei Pan, Sean Golden, Shoeleh Assemi, Marc Freddy Sime, Xuming Wang, Yuesheng Gao and Jan Miller

Minerals 2021, 11(3), 276; https://doi.org/10.3390/min11030276 - 08 Mar 2021

Cited by 17 | Viewed by 3230

Abstract

Respirable coal mine dust (RCMD) particles, particularly the nano-sized fraction (<1 μm) of the RCMD if present, can cause severe lung diseases in coal miners. Characterization of both the particle size and chemical composition of such RCMD particles remains a work in progress, [...] Read more.

Respirable coal mine dust (RCMD) particles, particularly the nano-sized fraction (<1 μm) of the RCMD if present, can cause severe lung diseases in coal miners. Characterization of both the particle size and chemical composition of such RCMD particles remains a work in progress, in particular, with respect to the nano-sized fraction of RCMD. In this work, various methods were surveyed and used to obtain both the size and chemical composition of RCMD particles, including scanning electron microscopy (SEM), scanning transmission electron microscopy (S-TEM), dynamic light scattering (DLS), and asymmetric flow field-flow fractionation (AsFIFFF). It was found that the micron-sized fraction (>1 μm) of RCMD particles collected at the miner location, from an underground coal mine, contained more coal particles, while those collected at the bolter location contained more rock dust particles. Two image processing procedures were developed to determine the size of individual RCMD particles. The particle size distribution (PSD) results showed that a significant amount (~80% by number) of nano-sized particles were present in the RCMD sample collected in an underground coal mine. The presence of nano-sized RCMD particles was confirmed by bulk sample analysis, using both DLS and AsFIFFF. The mode particle size at the peak frequency of the size distribution was found to be 300–400 nm, which was consistent with the result obtained from SEM analysis. The chemical composition data of the nano-sized RCMD showed that not only diesel particles, but also both coal and rock dust particles were present in the nano-sized fraction of the RCMD. The presence of the nano-sized fraction of RCMD particles may be site and location dependent, and a detailed analysis of the entire size range of RCMD particles in different underground coal mines is needed. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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15 pages, 3177 KiB

Open AccessArticle

The Impact of Ambient Atmospheric Mineral-Dust Particles on the Calcification of Lungs

by Mariola Jabłońska, Janusz Janeczek and Beata Smieja-Król

Minerals 2021, 11(2), 125; https://doi.org/10.3390/min11020125 - 27 Jan 2021

Cited by 1 | Viewed by 2931

Abstract

For the first time, it is shown that inhaled ambient air-dust particles settled in the human lower respiratory tract induce lung calcification. Chemical and mineral compositions of pulmonary calcium precipitates in the lung right lower-lobe (RLL) tissues of 12 individuals who lived in [...] Read more.

For the first time, it is shown that inhaled ambient air-dust particles settled in the human lower respiratory tract induce lung calcification. Chemical and mineral compositions of pulmonary calcium precipitates in the lung right lower-lobe (RLL) tissues of 12 individuals who lived in the Upper Silesia conurbation in Poland and who had died from causes not related to a lung disorder were determined by transmission and scanning electron microscopy. Whereas calcium salts in lungs are usually reported as phosphates, calcium salts precipitated in the studied RLL tissue were almost exclusively carbonates, specifically Mg-calcite and calcite. These constituted 37% of the 1652 mineral particles examined. Mg-calcite predominated in the submicrometer size range, with a MgCO₃ content up to 50 mol %. Magnesium plays a significant role in lung mineralization, a fact so far overlooked. The calcium phosphate (hydroxyapatite) content in the studied RLL tissue was negligible. The predominance of carbonates is explained by the increased CO₂ fugacity in the RLL. Carbonates enveloped inhaled mineral-dust particles, including uranium-bearing oxides, quartz, aluminosilicates, and metal sulfides. Three possible pathways for the carbonates precipitation on the dust particles are postulated: (1) precipitation of amorphous calcium carbonate (ACC), followed by its transformation to calcite; (2) precipitation of Mg-ACC, followed by its transformation to Mg-calcite; (3) precipitation of Mg-free ACC, causing a localized relative enrichment in Mg ions and subsequent heterogeneous nucleation and crystal growth of Mg-calcite. The actual number of inhaled dust particles may be significantly greater than was observed because of the masking effect of the carbonate coatings. There is no simple correlation between smoking habit and lung calcification. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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Review

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25 pages, 11104 KiB

Open AccessReview

Respirable Coal Mine Dust: A Review of Respiratory Deposition, Regulations, and Characterization

by Younes Shekarian, Elham Rahimi, Mohammad Rezaee, Wei-Chung Su and Pedram Roghanchi

Minerals 2021, 11(7), 696; https://doi.org/10.3390/min11070696 - 28 Jun 2021

Cited by 31 | Viewed by 5214

Abstract

In the late 1990s, despite years of efforts to understand and reduce coal worker’s pneumoconiosis (CWP) prevalence from more than 30% in 1970 to less than 4.2%, the level of occurrence among the US coal miners increased unexpectedly. The recent resurgence of lung [...] Read more.

In the late 1990s, despite years of efforts to understand and reduce coal worker’s pneumoconiosis (CWP) prevalence from more than 30% in 1970 to less than 4.2%, the level of occurrence among the US coal miners increased unexpectedly. The recent resurgence of lung diseases has raised concerns in the scientific and regulatory communities. In 2014, the United States Mine Safety and Health Administration (MSHA) issued a new dust rule changing the respirable coal mine dust (RCMD) exposure limits, measurement technology, and sampling protocol. The analysis for probable causes for the substantial increase in the CWP incidence rate is rather complicated. This paper aims to conduct a review of RCMD respiratory deposition, health effects, monitoring, regulations, and particle characteristics. The primary sources of RCMD along with the health risks from potential exposure are highlighted, and the current RCMD exposure regulations of the major coal producer countries are compared. A summary of RCMD characterization studies from 1972 to the present is provided. A review of the literature revealed that numerous factors, including geological and mining parameters, advancements in mining practices, particle characteristics, and monitoring approaches are considered to contribute to the recent resurgence of RCMD lung diseases. However, the root causes of the problem are still unknown. The effectiveness of the new dust rules in the United States will probably take years to be correctly assessed. Therefore, future research is needed to understand the relationship between RCMD particle characteristics and lung deposition, and the efficacy of current monitoring practices to measure the true dose of RCMD exposure. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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15 pages, 1579 KiB

Open AccessReview

Asbestiform Amphiboles and Cleavage Fragments Analogues: Overview of Critical Dimensions, Aspect Ratios, Exposure and Health Effects

by Gaia M. Militello, Laura Gaggero and Sebastiano La Maestra

Minerals 2021, 11(5), 525; https://doi.org/10.3390/min11050525 - 16 May 2021

Cited by 10 | Viewed by 3845

Abstract

The term asbestos refers to a group of serpentine (chrysotile) and amphibole (amosite, crocidolite, anthophyllite, tremolite and actinolite) minerals with a fibrous habit. Their chemical-physical properties make them one of the most important inorganic materials for industrial purposes and technological applications. However, the [...] Read more.

The term asbestos refers to a group of serpentine (chrysotile) and amphibole (amosite, crocidolite, anthophyllite, tremolite and actinolite) minerals with a fibrous habit. Their chemical-physical properties make them one of the most important inorganic materials for industrial purposes and technological applications. However, the extraction, use and marketing of these minerals have been prohibited due to proven harmful effects, mainly involving the respiratory system. In addition to the known six minerals classified as asbestos, the natural amphiboles and serpentine polymorphs antigorite and lizardite, despite having the same composition of asbestos, do not have the same morphology. These minerals develop chemical and geometric (length > 5 μm, width < 3 μm and length: diameter > 3:1), but not morphological, analogies with asbestos, which is regulated by the WHO. The debate about their potential hazardous properties is open and ongoing; therefore, their morphological characterization has a key role in establishing a reliable asbestos hazard scenario. This review focuses on evaluating the most relevant papers, evidencing the need for a reappraisal. Different in vitro, in vivo and epidemiological studies report information about cleavage fragments with critical dimensions similar to asbestos fibres, but very few works target fragments below 5 µm in length. Breathable smaller fibres could have deleterious effects on human health and cannot be disregarded from the risk assessment process. Furthermore, a few studies suggest that the carcinogenic nature of short fibres is not excluded. This review highlights that it is worth investigating the effects of this size range of elongated mineral particles and fibres. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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36 pages, 3761 KiB

Open AccessReview

Review of Respirable Coal Mine Dust Characterization for Mass Concentration, Size Distribution and Chemical Composition

by Behrooz Abbasi, Xiaoliang Wang, Judith C. Chow, John G. Watson, Bijan Peik, Vahid Nasiri, Kyle B Riemenschnitter and Mohammadreza Elahifard

Minerals 2021, 11(4), 426; https://doi.org/10.3390/min11040426 - 16 Apr 2021

Cited by 14 | Viewed by 5395

Abstract

Respirable coal mine dust (RCMD) exposure is associated with black lung and silicosis diseases in underground miners. Although only RCMD mass and silica concentrations are regulated, it is possible that particle size, surface area, and other chemical constituents also contribute to its adverse [...] Read more.

Respirable coal mine dust (RCMD) exposure is associated with black lung and silicosis diseases in underground miners. Although only RCMD mass and silica concentrations are regulated, it is possible that particle size, surface area, and other chemical constituents also contribute to its adverse health effects. This review summarizes measurement technologies for RCMD mass concentrations, morphology, size distributions, and chemical compositions, with examples from published efforts where these methods have been applied. Some state-of-the-art technologies presented in this paper have not been certified as intrinsically safe, and caution should be exerted for their use in explosive environments. RCMD mass concentrations are most often obtained by filter sampling followed by gravimetric analysis, but recent requirements for real-time monitoring by continuous personal dust monitors (CPDM) enable quicker exposure risk assessments. Emerging low-cost photometers provide an opportunity for a wider deployment of real-time exposure assessment. Particle size distributions can be determined by microscopy, cascade impactors, aerodynamic spectrometers, optical particle counters, and electrical mobility analyzers, each with unique advantages and limitations. Different filter media are required to collect integrated samples over working shifts for comprehensive chemical analysis. Teflon membrane filters are used for mass by gravimetry, elements by energy dispersive X-ray fluorescence, rare-earth elements by inductively coupled plasma-mass spectrometry and mineralogy by X-ray diffraction. Quartz fiber filters are analyzed for organic, elemental, and brown carbon by thermal/optical methods and non-polar organics by thermal desorption-gas chromatography-mass spectrometry. Polycarbonate-membrane filters are analyzed for morphology and elements by scanning electron microscopy (SEM) with energy dispersive X-ray, and quartz content by Fourier-transform infrared spectroscopy and Raman spectroscopy. Full article

(This article belongs to the Special Issue Mineralogy and Characteristics of Occupational and Environmental Dust Exposures)

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