Respirable Quartz Research Articles

Atmospheric emissions of respirable quartz from industrial activities in China

Atmospheric emissions of respirable quartz from industrial activities in China

Thin seams and small mines are associated with higher exposures to respirable crystalline silica in US underground coal mines

ObjectivesPrevious radiologic and histopathologic studies suggest respirable crystalline silica (RCS) overexposure has been driving the resurgence of pneumoconiosis among contemporary US coal miners, with a higher prevalence of severe disease...

101 Quantitative models for prediction of occupational exposure to respirable dust and quartz within the formulating, metal manufacturing and construction industries

101 Quantitative models for prediction of occupational exposure to respirable dust and quartz within the formulating, metal manufacturing and construction industries

Measuring Respirable Crystalline Silica (Quartz) from Powdery Materials through Sedimentation and X-ray Diffractometry.

When possible, choosing materials with a low quartz content is the most effective and cost-efficient way to prevent the respirable quartz exposure of workers and other end users of powdery products. Therefore, methods are needed to analyze low amounts of quartz from powdery products, such as sand, gravel, plaster, cement, and concrete. To this end, we present a method to analyze respirable dust and quartz from powdered materials, such as construction products. The method includes separation of the respirable dust fraction by liquid sedimentation, followed by gravimetric analysis and determination of the crystalline silica content by X-ray diffractometry. While also aiding in the development of less harmful products, analysis of the quartz concentration of powdery products is statutory in Eu countries, excluding natural products not chemically modified. According to EU Regulation No. 1272/2008, products must be classified if they contain harmful substances in concentrations above 0.1 wt.%, and clauses pertaining to cancerous properties and harmfulness to lungs should be included. Also, mineral producers in the EU recommend that products containing respirable quartz should be labelled based on their quartz concentration, provided the concentration exceeds 1 wt.%. The present method meets these needs. The analysis can be performed in parallel from 50 to 1000 mg (dry weight) of powdery materials. The quantitative limit of determination was 10 µg per sample, corresponding to 0.01 wt.%, and the linear range 0.02-10 wt.% (10-5000 µg quartz per sample, Pearson correlation coefficient 0.99). The accuracy of the method was 82% and the repeatability 11%.

98 Novel Stoffenmanager® Algorithms for Quantitative Estimation of Exposure to Respirable Dust and Quartz in Construction, Formulating and Metal Manufacturing Industry

Abstract Stoffenmanager® is a well-established and widely accepted tool that is applied for regulatory risk assessments (e.g. REACH). This online-tool enables companies to identify hazardous chemicals, chemical risks and to control exposure to hazardous substances at the workplace. In the current version, however, Stoffenmanager® is not applicable to all areas of activity with solids in which dusty hazardous substances are used or may arise. Therefore, the aim of this project is to expand the applicability domain of Stoffenmanager® by developing three innovative algorithms: 1) respirable dust and quartz for tasks with dusty products, 2) respirable dust for metal-cutting manufacturing and 3) respirable dust and quartz for the mechanical processing of stone. To derive new quantitative regression models calibration and validation measurement datasets on hazardous substances are required. In this project, a total of approximately 6000 data points including comprehensive contextual information were extracted from the IFA Exposure database MEGA and MEGA variables were converted into Stoffenmanager® variables. Subsequently, the variables were divided into classes with scores on a logarithmic scale. Spearman correlation coefficients were calculated, and in case of significant positive relationship between the Stoffenmanager® scores and the measurements statistical regression analyses were performed to calculate the regression equations. After the development of the new algorithms, exposure models were validated against exposure data from the MEGA database. Scatter plots and regression equations will be presented. The new algorithms serve to improve workers’ health by reducing occupational exposure to respirable dust and quartz which are known to be human carcinogens.

101 Novel Stoffenmanager® Algorithms for Quantitative Estimation of Exposure to Respirable Dust and Quartz in Construction, Formulating and Metal Manufacturing Industry

Abstract Stoffenmanager® is a well-established and widely accepted tool that is applied for regulatory risk assessments (e.g. REACH). This online-tool enables companies to identify hazardous chemicals, chemical risks and to control exposure to hazardous substances at the workplace. In the current version, however, Stoffenmanager® is not applicable to all areas of activity with solids in which dusty hazardous substances are used or may arise. Therefore, the aim of this project is to expand the applicability domain of Stoffenmanager® by developing three innovative algorithms: 1) respirable dust and quartz for tasks with dusty products, 2) respirable dust for metal-cutting manufacturing and 3) respirable dust and quartz for the mechanical processing of stone. To derive new quantitative regression models calibration and validation measurement datasets on hazardous substances are required. In this project, a total of approximately 6000 data points including comprehensive contextual information were extracted from the IFA Exposure database MEGA and MEGA variables were converted into Stoffenmanager® variables. Subsequently, the variables were divided into classes with scores on a logarithmic scale. Spearman correlation coefficients were calculated, and in case of significant positive relationship between the Stoffenmanager® scores and the measurements statistical regression analyses were performed to calculate the regression equations. After the development of the new algorithms, exposure models were validated against exposure data from the MEGA database. Scatter plots and regression equations will be presented. The new algorithms serve to improve workers’ health by reducing occupational exposure to respirable dust and quartz which are known to be human carcinogens.

130 An Exposure Assessment of dust- and Respirable Quartz Levels During Indoor Renovations

Abstract Construction workers are exposed to a complex mix of inorganic dust and other components. Workers doing interior demolition and renovation work are particularly at risk as the work operations can produce large quantities of dust in areas with low ventilation. The aim of this work is to assess the dust- and respirable quartz levels that workers in the construction industry are exposed to. An additional goal with the study is to investigate the inorganic components present in the respirable dust fraction using Rietveld as a multicomponent analysis with XRD. Workers in the construction industry have been carrying personal respirable air samplers during work with concrete and building bricks. Quartz content in respirable air samples is determined by X-ray powder diffraction (XRD) by using the NISOH 7500 method. Gravimetric analysis of 67 respirable dust samples gave a mean of 1.34 mg/m3 (min 0.028 mg/m3 to max 6.0 mg/m3). Initial determination of quartz content by XRD revealed a mean of 0.109 mg/m3 (n=52) respirable quartz, with a minimum, maximum and median of 0.0074 mg/m3, 0.60 mg/m3 and 0.045 mg/m3 respectively. The X-ray diffractograms show a complex mixture of inorganic components. These results show that construction workers may be exposed to levels above the current OEL for respirable quartz. It is therefore important to measure the quartz levels in this industry.

28 Evaluation of Work-Related Exposures to the Inhalable and Respirable Dust Fraction and to Respirable Quartz

Abstract Dust is found in the entire environment as well as in working areas. When assessing dust exposure at workplaces, measurements on inhalable and respirable dust are performed. Furthermore, quartz is used as an agent or is released in the form of respirable dust in a number of work processes. Between 2005 and 2016, 35,000 measurements on each dust fraction were performed in the “Measurement System for Exposure Assessment” – MGU. In addition, 15,000 measurements on respirable quartz were performed in this data period. These exposure data on the dust fractions and quartz was stored in the IFA exposure-database MEGA. Statistic evaluations of these data were done according to industrial sectors and work areas. Further grouping criteria like the measurement strategy ("personal measurements" and "stationary sampling") and the sampling time (≥ 2 hours and < 2 hours) help to describe the dust and quartz exposure at work places. Dust and quartz exposures occurring in working areas were analysed for about 20 different industrial sector groups like ceramic and glass industry, foundries, or metalworking and mechanical engineering. These sector groups were further divided in individual sectors and typical tasks performed in these sectors. For example, the tasks stone cutting in stone masonry, mixing and filling in the chemical industry or powder coating in the metalworking sector. The statistical evaluations from the MEGA database are published in IFA-reports about the exposure to inhalable and respirable dust and to quartz for prevention and for retrospective considerations.

Occupational quartz and particle exposure affect systemic levels of inflammatory markers related to inflammasome activation and cardiovascular disease

BackgroundThe inflammatory responses are central components of diseases associated with particulate matter (PM) exposure, including systemic diseases such as cardiovascular diseases (CVDs). The aim of this study was to determine if exposure to PM, including respirable dust or quartz in the iron foundry environment mediates systemic inflammatory responses, focusing on the NLRP3 inflammasome and novel or established inflammatory markers of CVDs.MethodsThe exposure to PM, including respirable dust, metals and quartz were determined in 40 foundry workers at two separate occasions per worker. In addition, blood samples were collected both pre-shift and post-shift and quantified for inflammatory markers. The respirable dust and quartz exposures were correlated to levels of inflammatory markers in blood using Pearson, Kendall τ and mixed model statistics. Analyzed inflammatory markers included: 1) general markers of inflammation, including interleukins, chemokines, acute phase proteins, and white blood cell counts, 2) novel or established inflammatory markers of CVD, such as growth/differentiation factor-15 (GDF-15), CD40 ligand, soluble suppressor of tumorigenesis 2 (sST2), intercellular/vascular adhesion molecule-1 (ICAM-1, VCAM-1), and myeloperoxidase (MPO), and 3) NLRP3 inflammasome-related markers, including interleukin (IL)-1β, IL-18, IL-1 receptor antagonist (IL-1Ra), and caspase-1 activity.ResultsThe average respirator adjusted exposure level to respirable dust and quartz for the 40 foundry workers included in the study was 0.65 and 0.020 mg/m3, respectively. Respirable quartz exposure correlated with several NLRP3 inflammasome-related markers, including plasma levels of IL-1β and IL-18, and several caspase-1 activity measures in monocytes, demonstrating a reverse relationship. Respirable dust exposure mainly correlated with non-inflammasome related markers like CXCL8 and sST2.ConclusionsThe finding that NLRP3 inflammasome-related markers correlated with PM and quartz exposure suggest that this potent inflammatory cellular mechanism indeed is affected even at current exposure levels in Swedish iron foundries. The results highlight concerns regarding the safety of current exposure limits to respirable dust and quartz, and encourage continuous efforts to reduce exposure in dust and quartz exposed industries.

Temporal Trends in Variability of Respirable Dust and Respirable Quartz Concentrations in the European Industrial Minerals Sector.

While between- and within-worker variability have been studied quite extensively, hardly any research is available that examines long-term trends in the variability of occupational exposure. In this first study on trends in occupational exposure variability temporal changes in the variability of respirable dust and respirable quartz concentrations within the European industrial minerals sector were demonstrated. Since 2000 the European Industrial Minerals Association's Dust Monitoring Program (IMA-DMP) has systematically collected respirable dust and respirable quartz measurements. The resulting IMA-DMP occupational exposure database contains at present approximately 40 000 personal full-shift measurements, collected at 177 sites owned by 39 companies, located in 23 European countries. Repeated measurements of workers performing their duties within a specific site-job-campaign combination allowed estimation of within- and between-worker variability in exposure concentrations. Overall day-to-day variability predominated the between-worker variability for both respirable dust concentrations and quartz concentrations. The within-worker variability in concentrations by job was two to three times higher for respirable quartz than for respirable dust. The median between-worker variability in respirable dust concentrations was low and further reduced over time. For quartz concentrations the same phenomenon albeit somewhat less strong was observed. In contrast, for the within-worker variability in concentrations downward and upward temporal trends were apparent for both respirable dust and respirable quartz. The study shows that the (relative) size of temporal variability is large and unpredictable and therefore regular measurement campaigns are needed to ascertain compliance to occupational exposure limit values.

Benefits and limitations of field-based monitoring approaches for respirable dust and crystalline silica applied in a sandstone quarry

With the advent of new sensing technologies and robust field-deployable analyzers, monitoring approaches can now generate valuable hazard information directly in the workplace. This is the case for monitoring respirable dust and respirable crystalline silica concentration levels. Estimating the quartz amount of a respirable dust sample by nondestructive analysis can be carried out using portable Fourier transform infrared spectroscopy (FTIR) units. Real-time respirable dust monitors, combined with small video cameras, allow advanced assessments using the Helmet-CAM methodology. These two field-based monitoring approaches, developed by the National Institute for Occupational Safety and Health (NIOSH), have been trialed in a sandstone quarry. Twenty-six Helmet-CAM sessions were conducted, and forty-one dust samples were collected around the quarry and analyzed on-site during two events. The generated data generated were used to characterize concentration levels for the monitored areas and workers, to identify good practices, and to illustrate activities that could be improved with additional engineered control technologies. Laboratory analysis of the collected samples complemented the field finding and provided an assessment of the performance of the field-based techniques. Only a fraction of the real-time respirable dust monitoring sessions data could be corrected with laboratory analysis. The average correction factor ratio was 5.0. Nevertheless, Helmet-CAM results provided valuable information for each session. The field-based quartz monitoring approach overestimated the concentration by a factor of 1.8, but it successfully assessed the quartz concentration trends in the quarry. The data collected could be used for the determination of a quarry calibration factor for future events. The quartz content in the dust was found to vary from 14% to 100%, and this indicates the need for multiple techniques in the characterization of respirable dust and quartz concentration and exposure. Overall, this study reports the importance of the adoption of field-based monitoring techniques when combined with a proper understanding and knowledge of the capabilities and limitations of each technique.

Outbreak of Silicosis in Workers Producing Artificial Stone Skirting Boards: A Novel Application of Silica-Based Composites

Outbreak of Silicosis in Workers Producing Artificial Stone Skirting Boards: A Novel Application of Silica-Based Composites

Application of a Fourier Transform Infrared (FTIR) Principal Component Regression (PCR) Chemometric Method for the Quantification of Respirable Crystalline Silica (Quartz), Kaolinite, and Coal in Coal Mine Dusts from Australia, UK, and South Africa.

This article describes the approach used to assess the performance of a Fourier transform infrared (FTIR) and principal component regression (PCR) chemometric method when measuring respirable quartz, kaolinite, and coal in samples from a variety of mines from different countries; relative to target assigned values determined using X-ray diffraction (XRD). For comparison, FTIR results using the partial least squares regression (PLSR) method are also available. Bulk dusts from 10 Australian mines were scanned using XRD and grouped into three sets based on the levels of quartz, kaolinite, and feldspar within their crystalline mineral composition. Prediction samples were generated from 5 of these Australian mine dusts, Durrans coal dust, 2 mine dusts from the UK, and a single South African mine dust (71 samples in total) by collecting the aerosolized respirable dust onto 25-mm diameter polyvinylchloride filters using the Safety in Mines Personal Dust Sampler (SIMPEDS) operating at 2.2 l min-1. The predicted values from the FTIR chemometric methods were compared with assigned target values determined using a direct on-aerosol filter XRD analysis method described in Method for the Determination of Hazardous Substances (MDHS) 101. Limits of detection (LOD) and uncertainty values for each analyte were calculated from a linear regression between target and predicted values. The uncertainty was determined using the calibration uncertainty equation for an unweighted regression. FTIR results from PCR and PLSR are very similar. For the PCR method, the LOD for quartz, kaolinite, and coal were 5, 25, and 71 µg, respectively. For quartz, an LOD of 5 µg corresponds to an airborne quartz concentration of 10 µg m-3, assuming a 4-h sampling time and collection flow rate of 2.2 l min-1. The FTIR measurement met the expected performance criteria outlined in ISO 20581 when sampling quartz for more than 4 h using a flow rate of 2.2 l min-1 at a concentration of 0.1 mg m-3 (100 µg m-3), the current workplace exposure limit in Great Britain. This method met the same performance criteria when measuring exposures at the Australian Workplace Exposure Standard (WES) concentration of 0.05 mg m-3, although in this case a sampling period greater than 8 h was needed.

Determinants of Respirable Quartz Exposure Concentrations Across Occupations in Denmark, 2018.

BackgroundHigh concentrations of respirable quartz have been reported from workers in construction, foundries, and quarries. Current exposure concentrations in prevalent but presumably lower exposed occupations have been less examined. We aimed to quantify current exposure concentrations of respirable dust and quartz across prevalent occupations and to identify determinants of respirable quartz exposure across these occupations.MethodsOne hundred and eighty-nine full-shift personal samples of respirable dust of workers within 11 occupations in Denmark were sampled during 2018. Respirable dust was determined gravimetrically and analysed for quartz content with infrared spectrometry. Determinants for respirable quartz exposure, i.e. use of power tools, outdoor or indoor location, and percentage of quartz in respirable dust, were analysed in linear mixed effect models.ResultsThe overall geometric means (geometric standard deviations) for respirable dust and quartz were 216 µg m−3 (4.42) and 16 µg m−3 (4.07), respectively. The highest quartz concentrations were observed among stone cutters and carvers [93 µg m−3 (3.47)], and metal melters and casters [61 µg m−3 (1.71)]. Use of power tools increased exposure concentrations of quartz by a factor of 3.5. Occupations explained 27%, companies within occupations 28%, and differences between workers within companies within occupations 14% of the variability in quartz concentrations. Thirty percent was due to day-to-day variability in exposure concentrations. In total, 19% of the variation in quartz concentration could be explained by type of tool, indoor/outdoor location, and percentage of quartz in respirable dust.ConclusionCurrent exposure concentrations are generally low, but some occupations in this study had average exposure concentrations to respirable quartz above the ACGIH threshold limit value of 25 µg m−3. Preventive measures to lower excess risk of quartz-related diseases among these workers are still needed. In terms of preventive strategies, use of power tools and quartz content of used materials were identified as main determinants of exposure. Lowering of exposures will be most efficient when focussed on these major determinants, e.g. tool dust control with water, dust extraction, and use of low quartz content materials.

Coal mine dust lung disease in miners killed in the Upper Big Branch disaster: a review of lung pathology and contemporary respirable dust levels in underground US coal mines

ObjectivesIn 2010, 29 coal miners died due to an explosion at the Upper Big Branch (UBB) mine in West Virginia, USA. Autopsy examinations of 24 individuals with evaluable lung tissue...

Raman spectroscopy and X‐ray diffraction responses when measuring health‐related micrometre and nanometre particle size fractions of crystalline quartz and the measurement of quartz in dust samples from the cutting and polishing of natural and artificial stones

AbstractAround 560 000 workers in Great Britain are potentially exposed to respirable crystalline silica (RCS), which can cause disabling diseases, such as silicosis and lung cancer. These experiments assessed the performance of a new Raman spectroscopy method for measuring RCS, in samples of pure quartz powder with different median aerodynamic particle diameters and stone dusts from variety of natural and artificial stones. The relationship between the Raman response and particle size was characterised by measuring subfractions of the respirable quartz standard A9950 collected using the Sioutas impactor. Bulk samples of quartz standards A9950 and Quin B that provided the highest median particle size diameters were also measured. Health‐related thoracic and respirable particle size fractions, and the environmental monitoring fractions of PM10, PM2.5, PM1 and PM0.5, were also collected during the powered cutting and polishing of sandstone and diorite (granite), engineered and sintered stones. All Raman spectroscopy results were compared with those from X‐ray diffraction (XRD), which was used as the reference technique. The Raman spectroscopy response closely followed the predicted crystallinity of RCS for different particle diameters. Raman spectroscopy obtained slightly higher percentages than XRD for particle size fractions below 1 μm. The Raman spectroscopy and XRD results were highly correlated for the thoracic, respirable and impactor fractions. The coefficients of determination were between 0.98 and 0.95. The slope coefficients for the correlation were 1.11 for the respirable fraction and 1.07 for the thoracic fraction. Raman spectroscopy is a promising alternative to XRD for measurement of RCS with a much lower limit of detection of 0.21 μg compared with 1 μg.

Development of a roof bolter drilling control process to reduce the generation of respirable dust

The drilling operation in the roof bolting process, especially in hard rock, generates excessive respirable coal and quartz dusts, which could expose the roof bolting operator to continued health risks. Previous research has shown that the amount of respirable dust produced is dependent on the main drilling parameters, specifically the drilling rotational and penetration rate. In this paper, a roof bolter drilling control process was proposed to reduce the generation of respirable dust. Based on the analysis of laboratory drilling test results, a rational drilling control process (adjusting rotational and penetration rates) to achieve the optimal drilling parameter for different rock types was proposed. In this process, the ratio between specific energy and rock uniaxial compressive strength was used as the index to determine the optimal operation point. The recommended drilling operation range for the rock type used in the experiment was provided, and the reduction in respirable dust generation was demonstrated. By following this control process, the drilling efficiency can be monitored in real time, so the system can stay in a relatively high-energy efficiency with less respirable dust production from the drilling source. This algorithm is targeted to be incorporated into the current roof bolter drilling control system for drilling automation so that a safe and productive drilling operation can be conducted in a healthy working environment.

Occupational exposure to dust and respirable quartz in coal briquettes ash handling worker

Occupational exposure to dust and respirable quartz in coal briquettes ash handling worker

Temporal trends in respirable dust and respirable quartz concentrations within the European industrial minerals sector over a 15-year period (2002–2016)

ObjectivesSince 2000 the European Industrial Minerals Association’s Dust Monitoring Programme (IMA-DMP) has systematically collected respirable dust and respirable quartz measurements from 35 companies producing industrial minerals. The IMA-DMP initiative allowed...

Quartz Dust Exposure Affects NLRP3 Inflammasome Activation and Plasma Levels of IL-18 and IL-1Ra in Iron Foundry Workers.

Purpose To study the association between inhalation of particulate matter or quartz in Swedish iron foundries and the effects on NLRP3 inflammasome activation. Methods Particle exposure measurements were performed during an eight-hour work day for 85 foundry workers at three Swedish iron foundries. Personal sampling was used for measurement of respirable quartz and dust and stationary measurements to obtain exposure measurements for inhalable dust and PM10. The NLRP3 inflammasome markers, interleukin- (IL-) 1β and IL-18, and inhibitors IL-1 receptor antagonist (IL-1Ra) and IL-18 binding protein (IL-18BP) were measured in plasma. Inflammasome activation was measured by caspase-1 enzymatic activity in monocytes in whole blood by flow cytometry, and expression of inflammasome-related genes was quantified using real-time PCR. Multiple linear regression analysis was used to investigate associations between PM exposures and inflammatory markers. Sex, age, smoking, current infection, BMI, and single nucleotide polymorphism in the inflammasome regulating genes CARD8 (C10X) and NLRP3 (Q705K) were included as covariates. Results The average exposure levels of respirable dust and quartz were 0.85 and 0.052 mg/m3, respectively. A significant exposure-response was found for respirable dust and IL-18 and for inhalable dust and IL-1Ra. Whole blood, drawn from study participants, was stimulated ex vivo with inflammasome priming stimuli LPS or Pam3CSK4, resulting in a 47% and 49% increase in caspase-1 enzymatic activity in monocytes. This increase in caspase-1 activity was significantly attenuated in the higher exposure groups for most PM exposure measures. Conclusions The results indicate that exposure levels of PM in the iron foundry environment can affect the NLRP3 inflammasome and systemic inflammation.