Asbestos Research Articles

Giant cell interstitial pneumonia: case series with comprehensive ultrastructural analyses of "not only" hard metal pneumoconiosis.

Giant cell interstitial pneumonia (GIP) is a fibrosing lung disease histologically characterized by centrilobular pulmonary fibrosis and cannibalistic intra-alveolar multinucleated giant cells. It is considered a form of pneumoconiosis caused particularly by secondary exposure to hard metals (cemented carbide or tungsten carbide). Hard metals are commonly used in various industrial applications, such as cutting tools, drilling tools, machine inserts, and other wear-resistant components. However, cases with unknown exposure that recurred in transplanted lungs have been described. This has led to the hypothesis of a complex etiopathogenesis, likely multifactorial, involving the coparticipation of immune mechanisms. We aimed to identify all the elements present in a series of GIP lung samples to better understand the pathogenic mechanisms of the disease. We describe five cases of histologically diagnosed GIP in patients with occupational exposure to metallic dust using ultrastructural characterization to identify metal dust and to quantify asbestos fibres. We found that tungsten was present in three cases, albeit in trace amounts in two of them. Numerous elements were identified in all samples, including asbestos fibres in patients with endstage pulmonary fibrosis. Furthermore, in one of the described cases the recurrence of the disease was also observed in transplanted lungs. These findings support the hypothesis that GIP may be due to elements other than hard metals, with asbestos possibly representing a contributory factor in the expression of a more severe fibrotic disease. The recurrence of GIP observed in transplanted organs strengthens the hypothesis of the existence of a not yet fully understood etiopathogenic immune mechanism.

Surveillance of asbestos related disease among workers enrolled in an exposure registry.

Contemporary asbestos exposure occurs during construction, remediation, and maintenance involving asbestos-containing materials (ACM), as compared to the historical exposure scenarios of asbestos mining and milling. The Ontario Asbestos Workers Register (AWR) was established in 1986 to track asbestos exposure among construction workers. This study reports on the risk of asbestos-related diseases (ARD) among workers in the AWR. AWR registrants were linked probabilistically with administrative health databases (1986-2019) to identify cases of ARD including both cancer and chronic respiratory disease. Follow-up began at AWR enrollment and continued prospectively. Incidence rates were compared to the general population using standardized incidence ratios (SIRs). Associations between ACM exposure and ARD were estimated among AWR registrants using Poisson regression. In total, 26,204 (81%) registrants were linked successfully. Common industries of employment were construction (62%), manufacturing (19%) and education (8%). Among men and women mesothelioma (M:SIR 6.83 [95% CI = 5.56-8.31]; W:SIR 19.2 [3.86-56.1]) and pulmonary fibrosis (M:SIR 14.1 [12.2-16.2]; W:SIR 9.25 [2.49-23.7]) rates were higher than the general population. Asbestosis risk was elevated among men (M:SIR 11.2 [9.59-13.1]). Workers with longer reported exposures (≥140 h) had increased rates of lung cancer (RR 1.34 [1.10-1.63]), mesothelioma (RR 2.83 [1.75-4.58]), asbestosis (RR 3.07 [2.12-4.43]), chronic obstructive pulmonary disease (RR 1.42 [1.29-1.57]), and pulmonary fibrosis (RR 1.88 [1.35-2.62]). Exposure to asbestos in construction and building maintenance continues to contribute to ARD incidence. Despite a Canadian ban on asbestos in new products, exposures to existing ACM will persist from construction activities. The AWR offers an opportunity for ongoing surveillance of resulting ARD in Ontario.

Modern Methods of Asbestos Waste Management as Innovative Solutions for Recycling and Sustainable Cement Production

Managing asbestos waste presents a significant challenge due to the widespread industrial use of this material, and the serious health and environmental risks it poses. Despite its unique properties, such as resistance to high temperatures and substantial mechanical strength, asbestos is a material with well-documented toxicity and carcinogenicity. Ensuring the safe removal and disposal of asbestos-containing materials (ACM) is crucial for protecting public health, the environment, and for reducing CO2 emissions resulting from inefficient waste disposal methods. Traditional landfill disposal methods have proven inadequate, while modern approaches—including thermal, chemical, biotechnological, and mechanochemical methods—offer potential benefits but also come with limitations. In particular, thermal techniques that allow for asbestos degradation can significantly reduce environmental impact, while also providing the opportunity to repurpose disposal products into materials useful for cement production. Cement, a key component of concrete, can serve as a sustainable alternative, minimizing CO2 emissions and reducing the need for primary raw materials. This work provides insights into research on asbestos waste management, offering a deeper understanding of key initiatives related to asbestos removal. It presents a comprehensive review of best practices, innovative technologies, and safe asbestos management strategies, with particular emphasis on their impact on sustainable development and CO2 emission reduction. Additionally, it discusses public health hazards related to exposure to asbestos fibers, and worker protection during the asbestos disposal process. As highlighted in the review, one promising method is the currently available thermal degradation of asbestos. This method offers real opportunities for repurposing asbestos disposal products for cement production; thereby reducing CO2 emissions, minimizing waste, and supporting sustainable construction.

Asbestos: Communicating the Health Issues Derived from Fibrous Minerals to Society

Asbestos, also known by its commercial name “amianthus”, has been widely used in various industries due to its unique properties. However, the extensive use of asbestos has had serious consequences for human health, most notably asbestosis, an irreversible chronic lung disease. Asbestosis increases the risk of lung cancer and malignant mesothelioma, both of which are fatal. Applied sciences such as microscopy (optical and scanning electron microscopy) and geochemistry have been fundamental in characterizing the mineral fibers of asbestos to understand its role in human health. We previously used these techniques to characterize these fibers; in this study, we explored the issues associated with asbestos and asbestosis, as well as the challenges facing science communication strategies in effectively informing society and workers about these risks. The lack of scientific culture, in general, has led to a lack of public awareness of the risks of asbestos. As such, effective communication and outreach plans and strategies, including the visualization of the fibers to demonstrate why problems arise if inhaled, must be implemented to address these challenges. Educational campaigns, guidelines, and plans that are informative and actionable, teaching workers, communities, and the public about the risks of asbestos are crucial. A general knowledge of mineralogy and geochemistry is needed, and providing and disseminating proper scientific communication may help to close the knowledge gap. We use examples and experience from Spain and Italy to illustrate this matter, as we have been working on the characterization of ultramafic complexes in these countries for more than ten years. Additionally, because these countries have strict laws for asbestos-containing materials, they are currently involved in retiring and demolishing buildings and infrastructure that contain asbestos.

Towards an improved wind effect assessment for asbestos abatement: A methodology for reduced-scale experiments

During building renovation or demolition, asbestos fibers can be released which can contaminate the environment, leading to potential occupational health and public health concerns. Strict asbestos abatement procedures and regulations are in place to mitigate this risk, which involve sealing the worksite and depressurizing it relative to the outdoor environment (i.e., indoor pressure lower than the outdoor pressure) using mechanical ventilation. However, the depressurization of the containment can be breached by the effects of the wind. Hence, it is essential to identify which wind conditions are problematic and how to prevent their effects. To conduct corresponding laboratory measurements, it is first required to scale down the building and its containment zone including a working mechanical ventilation system. This paper presents an innovative methodology for conducting reduced-scale experiments on buildings equipped with mechanical ventilation systems for contaminant containment. The methodology, here explained in the context of asbestos abatement, could also be applied to any other type of particulate pollutant. The methodology of this research study includes the design of a mechanical ventilation system for depressurization; a method to scale down the building and the ventilation system for testing in a wind tunnel; and 3D steady Reynolds averaged Navier-Stokes (RANS) simulations for optimizing the positioning of the ventilation components. The methodology is applied for a single-zone building including its ventilation system, which is found to achieve the targeted indoor depressurization of −40 Pa, making it ready for wind tunnel tests.

Ferritin adsorption onto chrysotile asbestos fibers influences the protein secondary structure

Asbestos fiber exposure triggers chronic inflammation and cancer. Asbestos fibers can adsorb different types of proteins. The mechanism of this adsorption, not yet completely understood, has been studied in detail mainly with serum albumin and was shown to induce structural changes in the bound protein. The findings of these works regarded mainly the changes of the protein structure, independently of any relation with asbestos-related diseases. For the first time, we have focused our attention to the consequences of the interaction between asbestos fibers and ferritin, a protein involved in iron metabolism, which is strongly modified in asbestos-related diseases. Even if it is known that ferritin can be adsorbed by asbestos fibers, the results of this interaction for the ferritin secondary structure has not previously been studied. One consequence of asbestos-ferritin interaction, is the formation of the so-called ferruginous/asbestos bodies (ABs). In the AB-coating material, the secondary structure of ferritin is modified, and at present, it is unclear whether or not this modification is a direct consequence of the asbestos interaction. In the present study, chrysotile asbestos, more than other asbestos fiber types tested, was found to rapidly bind holo-ferritin, and the presence of iron seemed to play a key role in this process, since iron-free apo-ferritin was adsorbed at a lower level, and iron-saturated chrysotile lost its ferritin-adsorbing capacity. To directly study the details of ferritin adsorption on asbestos fibers, High Resolution Transmission Electron Microscopy (HR-TEM) was employed together with FTIR microspectroscopy and Infrared nanoscopy, which to the best of our knowledge, have not previously been used for this purpose. Chrysotile-bound apo-ferritin underwent a significant change in secondary structure, showing a shift from a prevalent α-helix to a β-sheet conformation. Conversely, the adsorbed holo-ferritin structure appeared to be only weakly modified. These findings add a new potential mechanism to the toxic activities of asbestos: the fibers can modify the structure, and very likely, the function of adsorbed proteins. This, in relation to ferritin, could be a key mechanism in cell iron homeostasis alteration, typically reported in asbestos-related diseases.

Evaluation of asbestos dispersion during laser ablation of rocks containing Naturally Occurring Asbestos (NOA)

Health risks are often overlooked when the short-term consequences are not immediately apparent. During restoration work, cleaning actions can generate particles that pose health risks to workers through inhalation. This is particularly true in the case of asbestos fibres that might be spread out from the laser cleaning of buildings or heritage artifacts made of stone, such as serpentinite and other ultramafic rocks, that have a high probability of containing asbestos (e.g., chrysotile, tremolite asbestos, actinolite asbestos). To show workers the importance of wearing proper protection to prevent health injuries, several serpentinite samples, ascertained to contain asbestos minerals by specific investigations, have been laser ablated using ad hoc modified equipment in order to collocate a HEPA filter prone to collect all dust emitted during ablation. The powder deposited on the surface of these filters after laser ablation was analyzed, by Powder X -ray Diffraction (PXRD), Transmission Electron Microscopy combined with Energy Dispersive Spectroscopy (TEM/EDS), micro-Raman spectroscopy (μ-Raman) and Fourier-transform infrared spectroscopy (FTIR/ATR). The results confirmed the presence of asbestos fibres during the laser ablation of rocks containing Naturally Occurring Asbestos (NOA), emphasizing the importance of wearing appropriate personal protective equipment (PPE) during these procedures. Noteworthy, approximately 33 % of the analyzed fibres met the WHO criteria in size for respirable fibres. Furthermore, through our experiments, we also demonstrated that using tools that integrate filters into working tools would definitively further decrease the risk of fibres inhalation to workers.

Assessment of Optical and Scanning Electron Microscopies for the Identification and Quantification of Asbestos Fibers and Typical Asbestos Bodies in Human Colorectal Cancer Tissues

Asbestos research, identification, and quantification have been performed over the years, and the relationship between fiber inhalation and lung disease development is well defined. The same cannot be said for the gastroenteric system: the International Agency for Research on Cancer (IARC) believes that colorectal cancer (CRC) could be associated with asbestos exposure, but research has not demonstrated a casual nexus between exposure and CRC, despite highlighting an association tendency. The combination of scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) is the most applied technique in asbestos fiber identification in tissues and intestinal mucosa. In this study, SEM/EDS was applied to evaluate the presence of asbestos fibers and bodies (ABs) inside the tissue of eleven patients affected by CRC who had undergone environmental exposure due to living in an asbestos-polluted area where an Eternit plant had been active in the past. This technique was coupled with optical microscopy (OM) to verify whether the latter could be applied to evaluate the presence of these mineral phases, with the goal of understanding its suitability for identifying fibers and ABs in colon tissues. In addition to verifying the presence of fibers, this study allowed us to identify the deposition site of said fibers within the sample and possibly detect associated tissue reactions using OM, over a shorter time and at lower costs. Despite being a preliminary and descriptive work, the obtained results allowed us to propose a method involving first-sample OM observation to identify regulated (fibers with a length ≥ 5 μm, a thickness ≤ 3 μm, and a length/thickness ratio > 3) asbestos phases and ABs in the extra-respiratory system. In fact, OM and SEM/EDS provided similar information: no asbestiform morphology or ABs were found, but phyllosilicates and other inorganic materials were identified. This research needs to be continued using higher-resolution techniques to definitively rule out the presence of these fibers inside tissues whilst also increasing the number of patients involved.

Geological and mineralogical characterization of fibrous tremolite from Iacolinei quarry (Basilicata, Italy).

Naturally Occurring Asbestos (NOA) has drawn the attention worldwide when investigation revealed an increased incidence of malignant mesothelioma in population living near NOA sites. In Basilicata region (South Italy), population living in the villages of Castelluccio Superiore and Inferiore, Lauria, Latronico, Episcopia, San Severino Lucano, and Francavilla in Sinni may be considered at high risk of asbestos exposure because these villages are either surrounded by or built on NOA-rich ophiolitic outcrops. In this work we investigated an asbestos tremolite sample coming from the ophiolitic rocks outcropping in the quarry of Iacolinei, widely used in the past to extract aggregates for various applications. A detailed mineralogical characterization has been attained by using a multi-analytical approach (EMPA, SEM-EDS, TEM-EDS, Mössbauer, µ-Raman, X-ray powder diffraction, and thermal analysis). Morphological investigation highlighted that the sample is composed of long fibers (> 5 µm) with a significant fraction (ca. 55%) having width below 0.25 µm, considered the most biologically active fibers. Moreover, the crystal chemical characterization showed that Fe occurs at the octahedral sites of the tremolite structure. It should be noted that Fe plays a primary role in the toxicity of asbestos. Based on these results, the investigated asbestos tremolite may be considered a potent mesothelial carcinogen, requiring therefore special attention for public health protection purposes. Investigations using sentinel animals to assess the diffusion of the tremolite fibers into the environment from the serpentinite rocks and soils of Iacolinei quarry are in progress.

Pollution of the environment and building interiors during asbestos removal as a result of lack of negative pressure in the working areas

The paper presents examples of the consequences of the lack of negative pressure in the work zone during asbestos removal. The asbestos fibre concentrations generated in those work zones were relatively low. This was due to the leakage in barriers restricting the work zone. Therefore the asbestos content in the outside air, near the renovated rooms was increasing. In the cases discussed, these works resulted in short-term pollution of the building's outdoor air to a depth of up to 15 m. Such contamination can cover the entire interior of the building. This may lead to long-term retention of asbestos fibre in the facility, despite the completion of asbestos removal. For example, non-friable asbestos-cement sheets removal in those work conditions increased indoor air by contamination up to 3000 f/m3 (outside the work zone). In the case of removing friable asbestos inside the building type “LIPSK”, indoor air contamination locally was up 21,000–51,000 f/m3, and outside the work zone to 18,000–28,900 f/m3. These values are above the average concentration of asbestos fibres in the same type of buildings (< 300–400 f/m3) in regular use.

When detection and quantification of mineral fibres in natural raw materials are at their limit – the case of a clay from the Gomsiqe–Puka mining area (Albania)

Abstract. In today's global market, the movement of raw materials and goods in the free global market can lead to unintended consequences. One significant concern is the potential presence of contaminants and carcinogens, particularly when products originate from regions with less strict regulations and enforcement. This issue is particularly pertinent in the natural raw materials utilized in the global building materials market, where contamination by asbestos minerals can occur. Therefore, the screening of natural raw materials for asbestos content is crucial to mitigate the risk of exposure to carcinogens for both workers and the general public. In this study, we examine a challenging case involving a smectite–kaolinite clay from Gomsiqe–Puka, Albania, possibly containing mineral fibres. Detection and quantification of asbestos in this material push the boundaries of current experimental methods. Using transmission electron microscopy (TEM), micro-Raman spectroscopy, and electron probe microanalysis (EPMA), we identified the presence of asbestos tremolite, along with a rare fibrous variety of diopside. EPMA data allowed the advancement of some speculations on the origin of the observed tremolites, showing that Al-rich tremolites are typical of oceanic settings and Al-poor tremolites are more similar to continental tremolites. We also investigated the impact of milling on the detection and quantification of mineral fibres, testing different milling times. This investigation is crucial as it can influence the classification of the raw material as asbestos-containing material or not. Our findings indicate that tremolite, cleavage fragments, and elongated particles break down into smaller World Health Organization (WHO) fibres with increasing milling times (1–5 min). However, prolonged milling (10 min) leads to overgrinding, resulting in a decrease in the number of counted WHO fibres with a length exceeding 5 µm.

Use of Geological Maps in Detecting Asbestos-Related Diseases; A New Region in Anatolia.

To examine the potential relationship between the presence of asbestos-related diseases (ARDs) in the region of Kastamonu, Turkey. The places of birth of patients with ARDs and control subjects diagnosed between 2008 and 2019 and identified in a tertiary hospital in Istanbul. Soil samples were taken from plaster surfaces and quarries. The analysis was done with transmission electron microscopy. ARDs was detected in 55(17.9%) of 307 participants. Patients had a mean age of 68 ± 11 years. Residential proximity to ophiolites increased ARD incidence by 6.2% per kilometer ( P = 0.003). Birthplaces were identified as being inside an ophiolitic unit, or if they were not, the Google Earth software was used to determine the beeline distance between the settlement's center and the edge of the closest ophiolitic unit. The appropriate threshold for this case is 12.75 km, with 75% sensitivity and 87% specificity. ARDs due to naturally occurring asbestos (NOA) are present in hitherto unknown places. Geological maps including ophiolites can help locate these places.

Asbestos and the skills gap

The asbestos sector is unique within the built environment. The history of asbestos extends well beyond the 100 years that we are commonly aware of. It is known to be one of the most devastating workplace killers, with figures released by the Health and Safety Executive (HSE) demonstrating a current trend of approximately 5,000 deaths annually attributed to diseases caused by exposure to asbestos fibres. This paper looks at the highly specialised job roles that the industry struggles to attract fresh talent into. It summarises some of the statistics and make observations as to how asbestos continues to be a prevailing hazard affecting management, maintenance and modernisation of aging buildings across the UK. The aim is to continue to help educate the built environment sector about a unique culture of highly specialised persons that float between and around the realms of inspection, testing, certification, occupational hygiene, health and safety, and construction and demolition. The paper comments on the position of the industry in the current economic climate and proposes a change of attitude and understanding to progress and ensure the risk to human health posed by asbestos continues to be reduced and quality of service delivery improved.

Asbestos exposure diagnosis in pulmonary tissues.

The diagnosis of asbestosis requires different criteria depending on whether it is in a clinical or medical/legal setting. In the latter context, only when a "diffuse interstitial fibrosis associated to asbestos bodies (ABs)" is present, it can be said to be asbestosis. Considering the medical/legal setting, the diagnosis must be certain and proven. Unfortunately, it is often difficult to identify ABs by light microscopy (LM), but this does not mean that the diagnosis should be clinically excluded. Other parameters are important, such as working history and/or diagnostic imaging. In addition to LM, normally used for diagnosis, there are other techniques, e.g.: scanning electron microscopy with attached microanalysis microprobe (SEM/EDS), but they require tissue digestion and higher cost. A new approach with micro-Raman spectroscopy and SEM/EDS techniques is able to analyse histological sections without other manipulations that could interfere with analysis of asbestos fibres. In this work, we propose an algorithm for asbestosis diagnosis, especially in the forensic medical field, demonstrating the importance of close collaboration between multiple professionals.

Exploring microbial diversity and interactions for asbestos modifying properties

Asbestos poses a substantial environmental health risk, and biological treatment offers a promising approach to mitigate its impact by altering its chemical composition. However, the dynamics of microbial co-inoculation in asbestos bioremediation remain poorly understood. This study investigates the effect of microbial single cultures and co-cultures on modifying crocidolite and chrysotile fibers, focusing on the extraction of iron and magnesium. Seventy bacterial and eighty-three fungal strains were isolated from five diverse sites, characterized phylogenetically using the 16S rRNA gene and ITS region, respectively, and assessed for siderophore and organic acid production. Most bacterial strains were identified as Pseudomonas, while Penicillium predominated among fungal strains. Ten bacterial and 25 fungal strains were found to produce both organic compounds. Four microbial co-cultures (one bacterium-bacterium, two fungus-bacterium, and one fungus-fungus) exhibiting synergistic effects in plate assays, alongside their respective single cultures, were incubated with crocidolite and chrysotile. ICP-OES analysis revealed that in crocidolite, the co-culture HRF19–HRB12 removed more iron than their single cultures, while Penicillium TPF36 showed the highest iron removal. The co-culture of two Pseudomonas strains (HRB12–RB5) exhibited the highest magnesium concentration in the supernatant. In chrysotile, the co-culture HRB12–RB5 removed more iron than their individual cultures, with Penicillium TFSF27 exhibiting the highest iron concentration in the solution. Penicillium TFSF27 and the co-culture TFSF27–TPF36 demonstrated the highest magnesium removal. SEM-XRMA analysis showed a significant reduction in iron and magnesium content, confirming elemental extraction from the fibers' structure. This study significantly broadens the range of microbial strains capable of modifying asbestos fibers and underscores the potential of microbial co-cultures in asbestos remediation.

Effect of Synthetic Vitreous Fiber Exposure on TMEM16A Channels in a Xenopus laevis Oocyte Model.

Many years ago, asbestos fibers were banned and replaced by synthetic vitreous fibers because of their carcinogenicity. However, the toxicity of the latter fibers is still under debate, especially when it concerns the early fiber interactions with biological cell membranes. Here, we aimed to investigate the effects of a synthetic vitreous fiber named FAV173 on the Xenopus laevis oocyte membrane, the cell model we have already used to characterize the effect of crocidolite asbestos fiber exposure. Using an electrophysiological approach, we found that, similarly to crocidolite asbestos, FAV173 was able to stimulate a chloride outward current evoked by step membrane depolarizations, that was blocked by the potent and specific TMEM16A channel antagonist Ani9. Exposure to FAV173 fibers also altered the oocyte cell membrane microvilli morphology similarly to crocidolite fibers, most likely as a consequence of the TMEM16A protein interaction with actin. However, FAV173 only partially mimicked the crocidolite fibers effects, even at higher fiber suspension concentrations. As expected, the crocidolite fibers' effect was more similar to that induced by the co-treatment with (Fe3+ + H2O2), since the iron content of asbestos fibers is known to trigger reactive oxygen species (ROS) production. Taken together, our findings suggest that FAV173 may be less harmful that crocidolite but not ineffective in altering cell membrane properties.

Asbestos Hazard in Serpentinite Rocks: Influence of Mineralogical and Structural Characteristics on Fiber Potential Release

Naturally occurring asbestos (NOA) represents a matter of social and environmental concern due to its potential release in the atmosphere during rock excavation and grinding in quarry and road tunnel activities. In most cases, NOA occurs in serpentinites, i.e., rocks deriving from low-grade metamorphic hydration of mantle peridotites. The potential release of asbestos fibers from serpentinite outcrops depends on several features, such as serpentinization degree, rock deformation, weathering, and abundance of fibrous veins. In this study, we selected a set of serpentinite samples from a representative outcrop in Tuscany (Italy), and we analyzed them by Optical, Scanning, and Transmission Electron Microscopies. The samples were treated by grinding tests following the Italian guidelines Decrees 14/5/96 and 152/2006 for the determination of the Release Index (RI), i.e., the fiber amount released through controlled crushing tests. The fine-grained powder released during the tests was analyzed by quantitative Fourier transform infrared spectroscopy (FTIR) to determine the variety and the amount of released fibers and to assess the potential hazard of the different serpentinite samples. Results indicate that the amount of released fibers is mostly related to serpentinite deformation, with the highest RI values for cataclastic and foliated samples, typically characterized by widespread occurrence of fibrous veins. Conversely, massive pseudomorphic serpentinite revealed a very low RI, even if their actual chrysotile content is up to 20–25%. Based on our original findings from the RI results, a preliminary investigation of the outcrop at the mesoscale would be of primary importance to obtain a reliable hazard assessment of NOA sites, allowing the primary distinction among the different serpentinites lithotypes and the effective fiber release.

Transmission Electron Imaging and Diffraction of Asbestos Fibers in an SEM

Transmission Electron Imaging and Diffraction of Asbestos Fibers in an SEM

Recycling thermally detoxified asbestos-cement in stone-wool: An end-less-life material!

Deactivated (detoxified) asbestos-cement (DAC), i.e. asbestos-cement slates thermally treated at 1100 °C in order to convert the harmful asbestos fibers into non harmful mineral phases, has been successfully mixed with 74.6 wt% quartz sand and up to 63.2 wt% basalt sand, to produce stone wool with mechanical properties and composition competitive with commercial stone wool. The sample with 50 % DAC and 50 % basalt provided the best comparison with commercial stone wool in terms of liquidus temperature (lower than for the other mixtures) and Young’s modulus (higher). Through further composition optimization and utilization of multiple components, we estimate that future batches could utilize 70–75 % of DAC. These promising results and expectations highlight a feasible reuse of DAC as secondary raw material for stone wool production and a possible route to the elimination of a toxic waste from the environment and the preservation of primary raw materials.

Occupational exposure to chrysotile in an asbestos cement factory in Kyrgyzstan.

An increasing number of countries are banning the production and use of asbestos, in compliance with the ratification of the C162 Asbestos Convention and the Basel Convention, and in response to the call for its elimination in the ILO resolution and WHO reports on the health risks associated with asbestos. Nevertheless, several countries, including Kyrgyzstan, are still miners and/or manufacturers of asbestos. The main objective of the study is to assess the occupational exposure to chrysotile of workers engaged in a production facility of asbestos-cement products in Kyrgyzstan. Monitored workers (n = 16, for a total of n = 18 samples) were divided into 3 "Similar Exposure Groups" (SEGs; SEG-1: asbestos loading; SEG-2; asbestos-cement mixing; SEG-3: cutting of asbestos-cement sheets) according to EN 689 standard. Samples were collected through personal sampling and subsequently examined by means of scanning electron microscope equipped with an energy-dispersive spectrometer for the compositional analysis of each fibre. The numerical concentration of airborne asbestos fibres was henceforward determined by dividing the number of fibres and the volume of sampled air (expressed in the number of fibres per millilitre of air: ff/ml). Investigated workers resulted to be exposed to chrysotile fibres. Results (GM ± GSD) outlined extremely high exposure levels for SEG-1 (2.2±2.1 ff/ml) and SEG-3 (4.7±1.6 ff/ml) workers and lower-but still relevant-exposure values for SEG-2 (0.91±2.6 ff/ml) workers. The results obtained in this case study can help to document potentially critical situations of occupational exposure to asbestos that can still occur nowadays in low and middle-income countries where asbestos is still mined and processed.