Asbestos Research Articles

Oxidative Stress and DNA Damages Induced by Occupational Exposure to Asbestos: A Systematic Review.

Asbestos is one of the most important environmental and occupational carcinogens. Nevertheless, the mechanisms by which asbestos fiber exposure causes chronic diseases are not fully understood. We performed the first systematic review on the epidemiological evidence to examine the association between occupational exposure to asbestos and oxidative stress and DNA damage. In this systematic review study, the PubMed and Scopus databases were searched for English-language publications. Eleven cross-sectional studies were included in the systematic review. A literature search was conducted by the main keywords including "Asbestos", "crocidolite", "chrysotile", "amphibole", "amosite", "Oxidative Stress", "DNA Damage", and "DNA injury". To evaluate the quality of studies, the "Newcastle-Ottawa Quality Assessment Scale" (NOS) was used. Overall, 1235 articles were achieved by searching in databases. Finally, by considering the inclusion, and exclusion criteria, 11 articles were conducted for this study. These studies were published between 1986 and 2020. Oxidative stress and DNA damage can occur in exposure to asbestos. Among various biomarkers, 8-OHdG is the best. The analysis of 8-oxodG in asbestos workers can help identify subjects with a higher level of genotoxic damage. This systematic review suggests that oxidative stress and DNA damage are two main outputs of asbestos exposure. Therefore, oxidative stress and DNA damage biomarkers can be used for identifying subjects at higher risk of cancer. These findings support policy initiatives aimed at detecting and eliminating asbestos fiber exposure and preventing potential health hazards in occupational settings.

There is plenty of asbestos at the bottom. The case of magnesite raw material contaminated with asbestos fibres

Although all six asbestos minerals (the layer silicate chrysotile and five chain silicate species actinolite asbestos, amosite, anthophyllite asbestos, crocidolite and tremolite asbestos) are classified as carcinogenic, chrysotile is still mined and used in many countries worldwide. Other countries, like Italy, impose zero tolerance for all asbestos species, but conflicting views repress the development of globally uniform treaties controlling international trade of asbestos-containing materials. Hence, countries with more severe legislations against the use of these hazardous materials lack of an international safety net against importation of non-compliant products. This research reports the first discovery of commercial magnesite raw materials contaminated with white asbestos (chrysotile). X-ray powder diffraction and thermogravimetric/thermodifferential measurements showed the presence of serpentine group minerals in both the semi-processed (powder) and quarried material. The univocal identification of chrysotile in the powders was confirmed by its peculiar Raman bands of the OH stretching vibrations between 3500 and 3800 cm−1, with an intense peak at ∼3695 cm−1 and a weak contribution at ∼3647 cm−1. Transmission electron microscope showed that chrysotile forms fibres up to a few microns long and up to 80 nm thick with a nanotube structure characterized by inner channels as large as 30–40 nm. Fibres size analysis obtained by scanning electron microscopy indicates mean length and diameter of 5.95 and 0.109 μm with medians of 2.62 and 0.096 μm, respectively; some among the fibres analysed exhibit the so-called “Stanton size” (i.e., asbestos fibres longer than 8 μm and thinner than 0.25 μm that are strongly carcinogenic). Quantitative analysis showed a chrysotile content around 0.01 wt% not allowed by current regulations in Italy and many other countries. More generally, our findings demonstrate that without shared policies aimed at regulating asbestos circulation on the global market, “asbestos-free” national policies will inevitably fail.

Australia’s Ongoing Challenge of Legacy Asbestos in the Built Environment: A Review of Contemporary Asbestos Exposure Risks

Asbestos remains ubiquitous in the Australian built environment. Of the 13 million tonnes of asbestos products installed in earlier decades, an estimated 50% remain in situ today. Because of the extensive past use of asbestos, and the increasing age of these products, the potential for exposure to asbestos fibres in both indoor and outdoor environments remains high, even while the actual asbestos exposure levels are mostly very low. Sources of these exposures include disturbance of in situ asbestos-containing materials (ACMs), for example during renovations or following disaster events such as fires, cyclones and floods. Our understanding of the risk of asbestos-related disease arising from long-term low-level or background exposure, however, is poor. We provide the most up-to-date review of asbestos exposure risks currently affecting different groups of the Australian population and the settings in which this can manifest. From this, a need for low-level asbestos monitoring has emerged, and further research is required to address whether current exposure monitoring approaches are adequate. In addition, we make the case for proactive asbestos removal to reduce the risk of ongoing asbestos contamination and exposure due to deteriorating, disturbed or damaged ACMs, while improving long-term building sustainability, as well as the sustainability of limited resources.

The Influence of Simping Clamshell Addition on Disc Brake Pad Mechanical Properties

The brake pads made from asbestos are environmentally hazardous due to the friction and abrasion occurring during braking, resulting in the release of airborne asbestos fibers. These fibers pose various health risks to humans and contribute to environmental pollution. This study aims to analyze the influence of adding clamshell waste material on the mechanical properties of motorcycle disc brake pads. The research utilized an experimental approach, conducting tensile and friction tests on six samples with different compositions: 100% brake pads, 40% brake pads, 60% simping clamshell, 60% brake pads, 40% simping clamshell, 20% brake pads, 80% simping clamshell, 50% brake pads, 50% simping clamshell, and 100% brake pads. The results indicate that the sample comprising 50% used brake pads and 50% simping clamshell exhibited the smallest difference in thickness, measuring 0.05 mm or 0.59%, indicating the strongest adhesive strength and wear resistance compared to other variations. Thus, a higher simping clamshell composition sacrifices some tensile strength but offers improved elasticity, benefiting specific braking conditions.

Measurements of airborne asbestos fibres during refurbishing.

Although the use of asbestos fibres in building materials has been prohibited in Norway since 1985, asbestos-containing materials (ACMs) are still found in many buildings. Lack of knowledge and awareness of these materials may lead to exposure during refurbishing. The aim of this study was to investigate the airborne fibre concentration and classify fibres found during the abatement of various ACMs. The release of fibres during short-term work tasks, such as drilling and sawing, was also investigated. Parallel air samples were collected during asbestos abetment of different building materials and analysed with scanning electron microscope (SEM) and phase-contrast microscope (PCM), respectively. Material samples were analysed with SEM. A real-time fibre monitor was used to measure asbestos during short-term work. The highest fibre concentrations were measured for samples collected during the removal of asbestos insulating boards (1.5-4.5 fibres/cm3 [f/cm3]), and the numbers were relatively similar for SEM and PCM. A large difference in asbestos concentrations was found between SEM and PCM when analysing floor materials, which were probably caused by a high number of gypsum fibres that the PCM operator counted. Thin fibres (<0.2 µm in width) were included in the SEM count and constituted up to 50% of the total fibre concentration for the asbestos cement materials. The presence of other inorganic and organic fibres on these samples probably led to similar results between SEM and PCM. Short-term work led to peak concentrations above 30 f/cm3.

Limnological history of three lakes from the former asbestos mining region of Thetford Mines (southern Quebec, Canada)

Limnological history of three lakes from the former asbestos mining region of Thetford Mines (southern Quebec, Canada)

Novel soil reconstruction leads to successful afforestation of a former asbestos mine in southern Quebec, Canada

Novel soil reconstruction leads to successful afforestation of a former asbestos mine in southern Quebec, Canada

A Study on Optimum Use of Fly Ash and GGBS in Fiber Cement Sheet to Enhance Sustainable Manufacturing

The biproducts of different industries must be reused or recycled which will avoid disposal of waste materials in the environment in different forms to protect our environment. Also the hazardous material used for the manufacturing of the products to be eliminated or minimized. In this paper a study has been conducted for optimum use of fly ash generated from power plants and Ground Granulated Blast Furnace Slag (GGBS) generated from steel plants in the manufacturing of fiber cemented roofing sheets. Also different percentages of fly ash, GGBS and pulp were added during the manufacturing of fiber cement roofing sheets in a fiber cement roofing sheet manufacturing plant and the quality of the final product has been tested subsequently in the laboratory to minimize the use of cement and asbestos fiber. Different results have been achieved in different percentages of fly ash, cement, GGBS, wood pulp and asbestos fiber combination. It is found that up to 36% addition of fly ash is acceptable with respect to the quality acceptance criteria of the final product, above 36% degrades the quality of the product which doesn’t meet the BIS: 459 standard requirements. Similarly, 10.38% of GGBS can be added without hampering the quality of the product. Finally, the best combination of raw mix design as per environmental sustainability point of view as well as the economic point of view has been suggested for the sustainable manufacturing of fiber cement roofing sheets.

Asbestos: Mineralogical features and fiber analysis in biological materials

Asbestos is a mineral with unique physical and chemical properties that make it highly resistant to heat, fire, and corrosion. Nevertheless, exposure to asbestos fibers has been linked to serious health problems, including lung cancer, mesothelioma, and asbestosis. Despite the ban on asbestos usage, asbestos-related diseases are still a major cause of morbidity and mortality worldwide. Analyzing the mineralogical features and fiber analysis of asbestos in biological materials is critical for scenarios where an asbestos exposure history cannot be obtained, a clinical diagnosis cannot be made, or legal aspects necessitate further investigation. This review outlines the mineralogical features and fiber analysis techniques of asbestos in biological materials.

Study on Partially Replacing Cement with Groundnut Shell and Sugarcane Bagasse Ash with adding Asbestos Fibre

Abstract: The industrial waste contains many inorganic and toxic substances far away the acceptable limit which cause an impact on the environment. Scarcity of the const. materials used the natural resources like sand aggregates and stone aggregate. The partial replacement of aggregates is need for the future generation of concrete structures for the environment supportable. The partial replacement of aggregates is need for the future generation of concrete structures for the environment supportable. The depletion of the natural resources gets exhausted. We have think over the alternate replacement of the materials. In present work the partial replacement of the GSA,SBA with the Cement and the addition of asbestos fiber. Optimum value of strength in compression, split tensile and flexure came at GSA,SBA 12% replacement with the Cement and addition of asbestos fiber 0.5%. The workability of mixture increases and after that there is decrease in the workability of the concrete when we increase the percentage of GSA,SBA with the Cement. A series of experiment were carried out to measure the compressive strength, split tensile strength and flexural strength of the concrete. The results showed that the compressive strength, split tensile strength and flexural strength increases with the adding of the GSA,SBA with Cement and the addition of asbestos fiber.

A Study on Cement Partially Replaced with Chalk Powder and Coconut Fiber Ash with the Addition of Asbestos Fiber

Abstract: Concrete can be defined as a building material that can be composed by mixing gravel or broken stone, sand, cement, and water. The mixture can be poured into any shape, size of mould, which on hardening gives a solid stone like mass, the strength of hardened solid mass can be increased by adding admixtures. The main aim of the admixtures is to enhance the properties to some extend of the desired solid mass. In common man language concrete can be defined as mixture of paste and aggregates. The partial replacement of aggregates is need for the future generation of concrete structures for the environment supportable. The depletion of the natural resources gets exhausted. We have think over the alternate replacement of the materials. In present work the cement partially replaced by Chalk Powder, Coconut Fiber Ash with the addition of Asbestos Fibres. Optimum value of strength in compression, split tensile and flexure came at 18% replacement with 0.6% addition the strength is higher than conventional concrete. The workability of mixture increases and after that there is decrease in the workability of the concrete when we increase the percentage of Chalk Powder, Coconut Fiber Ash. A series of experiment were carried out to measure the compressive strength, split tensile strength and flexural strength of the concrete. The results showed that the compressive strength, split tensile strength and flexural strength increases with the adding of the Chalk Powder, Coconut Fiber Ash with the addition of Asbestos Fibres.

Detection of fine asbestos fibers using fluorescently labeled asbestos-binding proteins in talc

Asbestos contamination in common materials, including powdered talc used in manufacturing cosmetics, pharmaceuticals, and baby powder, is of great public concern. The use of polarized light microscopy (PLM) for asbestos detection is limited because it cannot detect fibers with diameters in the nano range. Furthermore, the use of electron microscopy (EM), the preferred method for determining asbestos contamination in talc, is hindered by a rather complicated and laborious process. Fluorescence microscopy (FM) is a simple analytical tool in modern life sciences, especially given its superior sensitivity and selectivity; however, it is rarely used for inorganic materials. Previously, we demonstrated that airborne asbestos fibers were fluorescently visualized under FM using fluorescently labeled asbestos-binding proteins. Here, we evaluated the FM method's feasibility in detecting fine asbestos fibers in powdered talc. The limit of detection of the fiber diameter of asbestos was approximately 0.06 µm using FM. The FM method's sensitivity surpassed that of PLM and approached that of EM, and thus, it can detect nano-scale fibers. Notably, the FM method enabled the selective visualization of asbestos fibers, including those hidden beneath numerous talc particles. A point counting method using FM images enabled a semi-quantitative analysis of 0.01–1.0% (w/w) asbestos contamination in talc.

Analysis of the Indian Government’s position on the use of asbestos and its health effects

Based on WHO guidance, all forms of asbestos are a health risk. In India, the mining of asbestos has been stopped, but chrysotile (a type of asbestos) is still imported and processed in large quantities. Chrysotile is mainly used for asbestos-cement roofing, and the manufacturers claim its use to be safe. We sought to understand the Indian Government’s position on the use of asbestos. To do so, we have analysed the replies of the executive wing of the Indian Government to questions on asbestos in the Indian Parliament. This revealed that, despite a mining ban, the government has defended the import, processing and continued use of asbestos.

Discovering of Asbestos Fibers and Corn Starch in Talc Material for Baby Powder Samples from Different Markets in Benghazi City

Discovering of Asbestos Fibers and Corn Starch in Talc Material for Baby Powder Samples from Different Markets in Benghazi City

Important functional role of the protein osteopontin in the progression of malignant pleural mesothelioma.

Malignant Pleural Mesothelioma (MPM) is an aggressive cancer of the mesothelial lining associated with exposure to airborne non-degradable asbestos fibers. Its poor response to currently available treatments prompted us to explore the biological mechanisms involved in its progression. MPM is characterized by chronic non-resolving inflammation; in this study we investigated which inflammatory mediators are mostly expressed in biological tumor samples from MPM patients, with a focus on inflammatory cytokines, chemokines and matrix components. Expression and quantification of Osteopontin (OPN) was detected in tumor and plasma samples of MPM patients by mRNA, immunohistochemistry and ELISA. The functional role of OPN was investigated in mouse MPM cell lines in vivo using an orthotopic syngeneic mouse model. In patients with MPM, the protein OPN was significantly more expressed in tumors than in normal pleural tissues and predominantly produced by mesothelioma cells; plasma levels were elevated in patients and associated with poor prognosis. However, modulation of OPN levels was not significantly different in a series of 18 MPM patients receiving immunotherapy with durvalumab alone or with pembrolizumab in combination with chemotherapy, some of whom achieved a partial clinical response. Two established murine mesothelioma cell lines: AB1 and AB22 of sarcomatoid and epithelioid histology, respectively, spontaneously produced high levels of OPN. Silencing of the OPN gene (Spp1) dramatically inhibited tumor growth in vivo in an orthotopic model, indicating that OPN has an important promoting role in the proliferation of MPM cells. Treatment of mice with anti-CD44 mAb, blocking a major OPN receptor, significantly reduced tumor growth in vivo. These results demonstrate that OPN is an endogenous growth factor for mesothelial cells and inhibition of its signaling may be helpful to restrain tumor progression in vivo. These findings have translational potential to improve the therapeutic response of human MPM.

Separation of asbestos concentrates in a hydrocyclone

Relevance. Issues related to the operation of hydrocyclones in the asbestos industry for the separation of finely split asbestos fibers from rock impurities and non-fluffed asbestos needles used in the wet enrichment of brittle chrysotile asbestos, as well as some types of amphibole asbestos and in the purification of commercial grades of chrysotile asbestos of normal strength from magnetite are considered. Purpose. The purpose and objectives of the research is to study the operating modes of a hydrocyclone for the separation and desliming of asbestos products. Particular attention is paid to the behavior of particles inside the hydrocyclone. Methodology. The formulas presented in the literature for calculating the volumetric delivery of hydro-cyclones are analyzed. As a result, it was determined that the volumetric delivery of the hydrocyclone does not depend on the size of the sand nozzle and that the influence of the latter affects mainly the specific distribution of water between the discharge and sand products. Results. In the course of processing the obtained experimental data, the calculation results showed that, at different nozzles and feed heads, the movement of grains of separation mesh in the internal flow of hydrocyclones of the tested design occurs within 1 &lt; Re &lt; 20. Therefore, the accepted dependences of Ψ on Re when deriving the calculated formulas are correct. Conclusions. The volumetric delivery of hydrocyclones D = 75 mm and D = 200 mm of the tested design for feeding and draining depends on the feed head and the diameter of the framework nozzle. The established regularities in the behavior of particles of asbestos concentrates in hydrocyclones are of practical importance and can be used when choosing the technological parameters of their operation to achieve the specified conditions for the size of particle separation mesh.

From field analysis to nanostructural investigation: A multidisciplinary approach to describe natural occurrence of asbestos in view of hazard assessment

The environmental impact of natural occurrences of asbestos (NOA) and asbestos-like minerals is a growing concern for environmental protection agencies. The lack of shared sampling and analytical procedures hinders effectively addressing this issue. To investigate the hazard posed by NOA, a multidisciplinary approach that encompasses geology, mineralogy, chemistry, and toxicology is proposed and demonstrated here, on a natural occurrence of antigorite from a site in Varenna Valley, Italy. Antigorite is, together with chrysotile asbestos, one of the serpentine polymorphs and its toxicological profile is still under debate. We described field and petrographic analyses required to sample a vein and to evaluate the NOA-hazard. A combination of standardized mechanical stress and automated morphometrical analyses on milled samples allowed to quantify the asbestos-like morphology. The low congruent solubility in acidic simulated body fluid, together with the toxicity-relevant surface reactivity due to iron speciation, signalled a bio-activity similar or even greater to that of chrysotile. Structural information on the genetic mechanism of antigorite asbestos-like fibres in nature were provided. Overall, the NOA site was reported to contain veins of asbestos-like antigorite and should be regarded as source of potentially toxic fibres during hazard assessment procedure.

Work-related respiratory health conditions among construction workers: a systematic narrative review

BackgroundEmerging evidence in both developed and developing countries indicate that occupational health hazards and diseases among construction workers constitute a significant public health challenge. While occupational health hazards and conditions...

Modification and Application of Materials for Strong Inhibitory Drilling Fluid

Due to the strong inhibition of drilling fluid, many polymer fluid loss additives can not play their role. Therefore, it is necessary to develop some water loss reducing materials that can withstand the strong inhibition environment. In this paper, the surface of asbestos fiber was modified and treated by indoor experiments. The physical and chemical properties of the obtained drilling fluid treatment samples were evaluated to optimize the appropriate amount of reagents used for surface treatment of asbestos. Subsequently, the drilling fluid performance of the obtained treatment agent samples were evaluated at different temperatures to analyze the effect of temperature on the drilling fluid performance. The surface of asbestos fiber was modified by adsorbed cationic surfactant CTAC which better solved the problem of entanglement of asbestos fiber in drilling fluid. The mechanism of the action of the surface of asbestos fiber was analyzed by scanning electron microscope observation experiments. Subsequently, different amounts of modified asbestos fiber was added to the drilling fluid and the performance of drilling fluid was evaluated at different temperatures. The experimental results showed that the modified asbestos fiber reduced the filtration loss of drilling fluid and still maintained good filtration loss reduction effect at 200°C.

Asbestos-Environment Pollution Characteristics and Health-Risk Assessment in Typical Asbestos-Mining Area.

Asbestos has been confirmed as a major pollutant in asbestos-mining areas that are located in western China. In general, asbestos-fibre dust will is released into the environment due to the effect of intensive industrial activities and improper environmental management, such that the health of residents in and around mining areas is jeopardised. A typical asbestos mining area served as an example in this study to analyse the content and fibre morphology of asbestos in soil and air samples in the mining area. The effects of asbestos pollution in and around the mining areas on human health were also assessed based on the U.S. Superfund Risk Assessment Framework in this study. As indicated by the results, different degrees of asbestos pollutions were present in the soil and air, and they were mainly concentrated in the mining area, the ore-dressing area, and the waste pile. The concentration of asbestos in the soil ranged from 0.3% to 91.92%, and the concentration of asbestos fibres in the air reached 0.008-0.145 f·cc-1. The results of the scanning-electron microscope (SEM) energy suggested that the asbestos was primarily strip-shaped, short columnar, and granular, and the asbestos morphology of the soils with higher degrees of pollution exhibited irregular strip-shaped fibre agglomeration. The excess lifetime cancer risk (ELCR) associated with the asbestos fibres in the air of the mining area was at an acceptable level (10-4-10-6), and 40.6% of the monitoring sites were subjected to unacceptable non-carcinogenic risks (HQ > 1). Moreover, the waste pile was the area with the highest non-carcinogenic risk, followed by the ore dressing area, a residential area, and a bare-land area in descending order. In the three scenarios of adult offices or residences in the mining area, adults' outdoor activities in the peripheral residence areas, and children's outdoor activities, the carcinogenic-and non-carcinogenic-risk-control values in the air reached 0.1438, 0.2225 and 0.1540 f·cc-1, and 0.0084, 0.0090 and 0.0090 f·cc-1, respectively. The results of this study will lay a scientific basis for the environmental management and governance of asbestos polluted sites in China.