Man-made Mineral Fibers Research Articles

Rounded atelectasis after exposure to refractory ceramic fibres (RCF)

BackgroundRefractory Ceramic fibres (RCF) are man-made mineral fibres used in high performance thermal insulation applications. Analogous to asbestos fibres, RCF are respirable, show a pleural drift and can persist in human lung tissue for more than 20 years after exposure. Pleural changes such as localised or diffuse pleural thickening as well as pleural calcification were reported.ResultA 45 years old man worked in high performance thermal insulation applications using refractory ceramic fibres (RCF) for almost 20 years. During a occupational medical prophylaxis to ensure early diagnosis of disorders caused by inhalation of aluminium silicate fibres with X-ray including high-resolution computed tomography (HRCT), bilateral pleural thickening was shown and a pleural calcification next to a rounded atelectasis was detected. Asbestos exposure could be excluded. In pulmonary function test a restrictive lung pattern could be revealed. In work samples scanning electron microscopy (SEM) including energy dispersive X-ray analysis (EDX) classified used fibres as aluminium silicate fibres. X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) showed crystalline as well as amorphous fibres.ConclusionsA comprehensive lung function analysis and in case of restrictive lung disorders additional CT scans are needed in RCF exposed workers in accordance to the guidelines for medical occupational examinations comparable to asbestos exposed workers.

Comprehensive hygienic assessment of the dust factor in the manufacturing heat-insulating building products from man-made mineral fibers

Introduction. Air pollution with aerosols of mineral fibers in the manufacturing heat-insulating building products is the primary harmful production factor that can increase the risks of developing several diseases of various organs and systems. It determines the relevance of conducting comprehensive studies of the dust factor in such industries, assessing the relationship between mass measurements and fibre counts, the development of targeted preventive measures, considering the features of the technological process. The study aims to conduct comprehensive hygienic studies of the dust factor in the manufacturing heat-insulating building products from basalt fiber and determine the morphological features of dust at different stages of the technological process, the presence of a relationship between mass measurements and fibre counts. Materials and methods. The studies were carried out based on manufacturing heat-insulating building products from basalt fiber. To assess the dust factor, the authors carried out the analysis of mass measurements of dust and fibre counts using phase-contrast light microscopy. The authors used linear regression analysis to study the dependence of the mass measurements and fibre counts. Results. The mass measurements of dust in the working area don't exceed hygienic standards and ranges from 0.51 mg/m3 to 1.19 mg/m3, and the fibre counts are from 0.45 f/cm3 to 1.23 f/cm3. The morphological analysis of the dust samples' preparations collected on filters from the air of the working area made it possible to reveal the characteristic features of the composition of the dust at various stages of the technological process. The study confirmed a positive correlation of weak strength between fibre counts and the mass measurements. The resulting dependence model is statistically significant, but the coefficient of determination of this model (R2) is 0.043. Fibre counts in the first phase of the production cycle are significantly higher than in the second. Simultaneously, the mass measurements do not have significant differences in different phases of the production cycle. Conclusions. There is a positive correlation of weak strength between fibre counts and mass measurements, but the resulting linear regression model can explain only 4.3% of the variation of fibre counts based on the mass measurements, which does not allow using this model for converting of the results of measurements of several particles. Microscopy of dust preparations makes it possible to determine the morphological picture characteristic of various stages of the technological process. Fibre counts depend on the phase of the production cycle. The data obtained can be used to design air purification systems and operating modes at various stages of the technological process.

Detection and comparison of fiber count concentration in processing environment of asbestos and man-made mineral fiber

Objective: To connect with the measurement data of asbestos dust fiber concentration in foreign countries, improve the accuracy of asbestos fiber detection in China, and understand the dust exposure in the working environment of asbestos and man-made mineral fiber production and processing sites in Zhejiang Province. The fiber count concentrations of working environment in glass fiber, ceramic fiber and asbestos processing plants were measured and compared. Methods: The dust concentration in the working environment of two glass fiber factories, one ceramic fiber factory and eight asbestos products processing factories was measured. The total dust mass concentration was measured according to GBZ/T 192.1-2007, and the fiber count concentration was measured by phase contrast microscope. Kruskal Wallis was used to test and compare the dust concentration in the working environment of each post. The correlation between asbestos mass concentration and fiber count concentration was analyzed by Spearman correlation. Results: Under the phase contrast microscope, there were many short and fine asbestos fibers in the field of vision, and there were many impurities around. The average dust concentration of asbestos processing plant was 3.2 f/ml, and the dust concentration of cotton ginning was the highest (6.68 f/ml) . There was a significantly positive correlation between asbestos fiber count concentration and mass concentration (r=0.535, P=0.033) . The average fiber count concentration of glass fiber factory was 0.001 f/ml, and the highest was 0.005 f/ml. The average fiber count concentration of ceramic fiber factory was 0.001 f/ml, and the highest was 0.006 f/ml. Conclusion: The fiber count concentration in the working environment of asbestos factory in Zhejiang Province is obviously over the standard, which is one of the important reasons for the high incidence of mesothelioma in this area. Short and small asbestos fibers are easy to be ignored when counting. It is necessary to improve the actual operation process of fiber counting to form a laboratory standard in China.

Комплексная гигиеническая оценка условий труда работников, подвергающихся воздействию аэрозолей искусственных минеральных волокон

Комплексная гигиеническая оценка условий труда работников, подвергающихся воздействию аэрозолей искусственных минеральных волокон

Airborne fiber particles: Types, size and concentration observed in Beijing

Airborne fibers are of public concern because of their potential threat to the environment, however their physical and chemical properties are poorly understood. Fibers are defined as having an aspect ratio >3:1. Fiber particles were collected in the near surface air, surface deposited dust and building materials in Beijing. They were examined using analytical scanning electron microscopy. The particles were initially classified into two categories: organic and inorganic. Organic fibers comprised microplastic and natural organic fiber particles. Inorganic fibers were mainly man-made mineral fibers (MMMFs), asbestos (represented by chrysotile), calcium sulfate and metal fiber particles. Microplastic and MMMFs fibers were most abundant, accounting for 34.6% and 40.3% in total, respectively, followed by asbestos (7.8%), calcium sulfate (7.2%), metal fibers (5.6%) and natural organic fiber particles (4.5%). The number-concentration of these particles was about 16.7 × 10−3 fibers/ml at 1.5 m above the ground and about 14.1 × 10−3 fibers/ml at about 18 m, suggesting the particles were mainly derived from surface and were re-suspended. Approximately 80% of the airborne fiber were smaller than 20 μm in length, which is possibly the critical size for fiber particles to re-suspend into the air. Surface dust and construction sites were speculated to be the major contributors of the fiber particles.

Peculiarities of morbidity and assessment of occupational health risks for workers who contact aerosols of man-made mineral fibers

Peculiarities of morbidity and assessment of occupational health risks for workers who contact aerosols of man-made mineral fibers

Man-made mineral fiber effects on the expression of anti-oncogenes P53 and P16 and oncogenes C-JUN and C-FOS in the lung tissue of Wistar rats

Man-made mineral fibers (MMMFs) are substitutes for asbestos. MMMFs are widely used as insulation, but their molecular mechanisms underlying the tumorigenic effects in vivo have been poorly studied. For this reason, this work aimed to explore the properties and carcinogenic molecular mechanisms of MMMFs. The three MMMFs, rock wool (RW), glass fibers (GFs), and ceramic fibers (CFs), were prepared into respirable dust. Particle size, morphology, and chemical composition were analyzed by laser particle analyzer, scanning electron microscope, and X-ray fluorescence spectrometer, respectively. The Wistar rats were administered multiple intratracheal instillations of three MMMFs once a month. Then, several parameters (e.g. body mass, lung mass, and lung histology) were measured at 1, 3, and 6 months. After that, levels of P53, P16, C-JUN, and C-FOS mRNA and protein were measured by quantitative real-time reverse transcription polymerase chain reaction and Western blotting. This work found that exposure to MMMFs could influence the growth of body mass and increase lung mass. General conditions showed white nodules and irregular atrophy. In addition, MMMFs could lead to inactivation of anti-oncogene P16 and activation of proto-oncogenes (C-JUN and C-FOS) in the mRNA and protein levels, in which GF and CF were more obvious compared with RW. The effect of MMMFs was different, which may be related to the physical and chemical characteristics of different MMMFs. In conclusion, MMMFs (GF and CF) could induce an unbalanced expression of cancer-related genes in the lung tissues of rats. The understanding of the determinants of toxicity and carcinogenicity provides a scientific basis for developing and introducing new safer MMMF products, and the present study provides some useful insights into the carcinogenic mechanism of MMMFs.

N-acetylcysteine prevents cytotoxic effects induced by man-made mineral fibers in a human bronchial epithelial cell line

Man-made mineral fibres (MMMFs) such as glass wool (GW), rock wool (RW) and refractory ceramic fibres (RCFs) are widely used as substitutes of asbestos. The present study aimed to investigate the cytotoxic effects on human bronchial epithelial cells (BEAS-2B) exposed to GW1, RW1 and RCF2, considering their properties similar to that of asbestos. We assessed cell viability; cell morphological changes; apoptotic rate; DNA damage; reactive oxygen species (ROS) generation; activities of caspase-3, caspase-8 and caspase-9; and expression levels of FasL, phosphorylated p38, and total p38 MAPK proteins. N-acetyl-l-cysteine (NAC) was used as an ROS scavenger. We observed that MMMFs, especially RCF2, evidently changed cellular morphology, promoted DNA damage, and induced apoptosis. In addition, the cytotoxicities of MMMFs were dependent on ROS generation, and NAC could decrease their toxicity. Furthermore, our results showed that apoptosis induced by MMMFs was mediated by the mitochondrial apoptotic pathway and Fas death receptor pathway. Moreover, the p38 MAPK signalling pathway was also involved in the cytotoxicities of MMMFs. NAC exerts a protective effect against apoptosis and DNA damage induced by GW1, RW1 and RCF2. This study provides important implications for understanding the potential toxic effects of GW1, RW1 and RCF2 exposure; it also indicates that NAC may prevent respiratory diseases induced by exposure to MMMFs.

Refractory ceramic fibers: Fiber characteristics, potential health effects and clinical observations

Refractory ceramic fibers (RCFs) are amorphous fibers that belong to a class of materials termed synthetic vitreous fibers (SVFs), also called man-made mineral fibers (MMMFs), which includes alkaline earth silicate wool, glass wool, rock (stone) wool, slag wool, and special-purpose glass fibers. RCFs are more durable and biopersistent than several other SVFs, although very much less biopersistent than either amosite or crocidolite asbestos. Chronic inhalation studies indicated that rats and hamsters exposed to RCF fibers developed fibrosis and tumors. Epidemiological studies at the University of Cincinnati funded by the Industry indicated that exposed workers; (1) exhibited symptoms (e.g., dyspnea) similar to those reported in other dust-exposed populations, (2) developed statistically, but not clinically, significant deficits in certain measures of pulmonary function in a cross sectional study, but no excessive decline in a longitudinal study, and (3) a dose related increase in pleural plaques, but no interstitial fibrosis. The 2003 mortality study indicated no incremental lung cancer and no cases of mesothelioma. RCF producers developed a comprehensive industry wide product stewardship program (PSP) beginning in the late 1980s. In conjunction with the PSP, there has been a progressive decrease in the TWA concentration of fibers by manufacturers and end-users. The research program has successfully produced more soluble fibers and undertaken efforts to develop larger diameter fibers. The results of the ongoing epidemiology studies confirm that occupational exposure to RCF is associated with the development of pleural plaques and minor decrements in lung function, but no interstitial fibrosis or incremental lung cancer.

Asbestos in recycled materials – modern risks and future concerns

The presence of asbestos fibres and asbestos-containing materials within recycled building materials is not a new phenomenon, but due to increased awareness and therefore increased analysis of these recycled materials, it has become an additional contaminant for developers to consider when investigating construction sites. Further to this, asbestos replacements such as man-made mineral fibre and refractory ceramic fibre currently being used in construction may be the problems of the future, the risks of which should be considered now.

EV@LUTIL: An open access database on occupational exposures to asbestos and man-made mineral fibres.

The aim of Evalutil is to document occupational exposure to asbestos and man-made mineral fibers. These databases provide grouped descriptive and metrological data from observed situations of occupational exposure, collected through the analysis of scientific articles and technical reports by industrial hygienists. Over 5,000 measurements were collected. We describe the occupations, economic activities, fiber-containing products, and operations on them that have been documented most often. Graphical measurement syntheses of these data show that the situations presented for asbestos and RCF, except mineral wools, report fiber concentrations mainly above historical occupational exposure limits. Free access to these data in French and in English on the Internet (https://ssl2.isped.u-bordeaux2.fr/eva_003/) helps public health and prevention professionals to identify and characterize occupational exposures to fibers. Extended recently to nanoscale particles, Evalutil continues to contribute to the improvement of knowledge about exposure to inhaled particles and the health risks associated with them.

Man-made mineral fibers and interstitial lung diseases

Manufactured (artificial) fibers represent an important and continuously growing volume among substitutes to natural fibers. A major proportion of the population in an industrialized society has been, is, or will be in contact with these fibers. The fibrous configuration of asbestos is well recognized as being an important parameter in toxicity, and now that of synthetic fibers is also suspected of inducing serious health effects on the respiratory system. There is an ongoing debate about the actual fibrogenic effect of these man-made mineral fibers (MMMFs) in humans. Several case reports have demonstrated the biopersistance of MMMFs in the lung of workers who were exposed to rock wool or fiberglass for long periods of time and were diagnosed with interstitial pulmonary fibrosis. A 20-year follow up also identified refractory ceramic fibers in workers' lung tissue, with significant association between cumulative fiber exposure and radiographic pleural changes. Newly emerging man-made fiber industries appear to induce new types of occupational diseases. Exposure of workers in MMMFs production plants is correlated to high risk for developing pneumoconiosis. Large epidemiological studies are needed in order to determine dose metrics for risk assessment and management.

Man-Made Mineral Fibers and the Respiratory Tract

Man-made mineral fibers are produced using inorganic materials and are widely used as thermal and acoustic insulation. These basically include continuous fiberglass filaments, glass wool (fiberglass insulation), stone wool, slag wool and refractory ceramic fibers. Likewise, in the last 2 decades nanoscale fibers have also been developed, among these being carbon nanotubes with their high electrical conductivity, mechanical resistance and thermal stability. Both man-made mineral fibers and carbon nanotubes have properties that make them inhalable and potentially harmful, which have led to studies to assess their pathogenicity. The aim of this review is to analyze the knowledge that currently exists about the ability of these fibers to produce respiratory diseases.

Fibras minerales artificiales y aparato respiratorio

Man-made mineral fibers are produced using inorganic materials and are widely used as thermal and acoustic insulation. These basically include continuous fiberglass filaments, glass wool (fiberglass insulation), stone wool, slag wool and refractory ceramic fibers. Likewise, in the last two decades nanoscale fibers have also been developed, among these being carbon nanotubes with their high electrical conductivity, mechanical resistance and thermal stability. Both man-made mineral fibers and carbon nanotubes have properties that make them inhalable and potentially harmful, which have led to studies to assess their pathogenicity. The aim of this review is to analyze the knowledge that currently exists about the ability of these fibers to produce respiratory diseases.

Investigation of occupational and environmental causes of respiratory cancers (ICARE): a multicenter, population-based case-control study in France.

BackgroundOccupational causes of respiratory cancers need to be further investigated: the role of occupational exposures in the aetiology of head and neck cancers remains largely unknown, and there are still substantial uncertainties for a number of suspected lung carcinogens. The main objective of the study is to examine occupational risk factors for lung and head and neck cancers.Methods/designICARE is a multi-center, population-based case-control study, which included a group of 2926 lung cancer cases, a group of 2415 head and neck cancer cases, and a common control group of 3555 subjects. Incident cases were identified in collaboration with cancer registries, in 10 geographical areas. The control group was a random sample of the population of these areas, with a distribution by sex and age comparable to that of the cases, and a distribution by socioeconomic status comparable to that of the population. Subjects were interviewed face to face, using a standardized questionnaire collecting particularly information on tobacco and alcohol consumption, residential history and a detailed description of occupational history. Biological samples were also collected from study subjects. The main occupational exposures of interest are asbestos, man-made mineral fibers, formaldehyde, polycyclic aromatic hydrocarbons, chromium and nickel compounds, arsenic, wood dust, textile dust, solvents, strong acids, cutting fluids, silica, diesel fumes, welding fumes. The complete list of exposures of interest includes more than 60 substances. Occupational exposure assessment will use several complementary methods: case-by-case evaluation of exposure by experts; development and use of algorithms to assess exposure from the questionnaires; application of job-exposure matrices.DiscussionThe large number of subjects should allow to uncover exposures associated with moderate increase in risks, and to evaluate risks associated with infrequent or widely dispersed exposures. It will be possible to study joint effects of exposure to different occupational risk factors, to examine the interactions between occupational exposures, tobacco smoking, alcohol drinking, and genetic risk factors, and to estimate the proportion of respiratory cancers attributable to occupational exposures in France. In addition, information on many non-occupational risk factors is available, and the study will provide an excellent framework for numerous studies in various fields.

Occupational risks and lung cancer burden for Chinese men: a population-based case–referent study

We aimed to fill in the gap of knowledge on the lung cancer burden resulting from occupational exposures among Chinese men through a population-based case-referent study. Detailed information on lifestyle and full occupational histories of 1,208 male lung cancer incident cases and 1,069 age-matched male community referents were obtained through interviews during 2004-2006. The associations between lung cancer risk and exposures to specific or group of agents that were confirmed or suspected occupational carcinogens were analyzed. After adjustment of smoking and other potential confounding factors, significant odds ratio of lung cancer was observed for workers employed in major industrial divisions of "construction" (1.37, 95% CI: 1.00-1.89) and "financing, insurance, real estate, and business services" (0.48, 95% CI: 0.23-0.97), as well as in the occupational groups of "bricklayers, carpenters, and other construction workers" (1.49, 95% CI: 1.07-2.06). Significantly elevated odds ratios were found for occupational exposures to silica dust (1.75, 95% CI: 1.16-2.62), welding fumes (1.74, 95% CI: 1.13-2.68), diesel exhaust (2.18, 95% CI: 1.23-3.84), and man-made mineral fibers (7.45, 95% CI: 1.63-34.00), while a significantly reduced risk (OR = 0.67, 95% CI: 0.47-0.95) was linked to cotton dust. The population attributable fraction of lung cancer was 3.2% (95% CI: 0.1-7.3%) for construction workers and 9.5% (95% CI: 4.8-15.1%) for the four significant specific exposures. Our study indicates that previous exposure to occupational carcinogens remains an important determinant of lung cancer burden for Hong Kong Chinese men. However, results obtained from this study should be confirmed by future analyses based on job exposure matrix.

Lung cancer and occupational exposures in Hong Kong Chinese men

ObjectivesWe aimed to quantify lung cancer risk associated with occupational exposures in Hong Kong Chinese men.MethodsA population-based case-referent study was carried out during 2004–6. Full occupational histories and other information...

Increased mortality from infectious pneumonia after occupational exposure to inorganic dust, metal fumes and chemicals

ObjectivesThere are epidemiological studies indicating that exposure to metal fumes is a risk factor for infectious pneumonia. Whether occupational exposure to other agents, such as inorganic dust or chemicals, also...

Magnetometric evaluation of toxicities of chemicals to the lungs and cells

Because the lungs are exposed to airborne hazardous materials, alveolar macrophages (AMs) play a major role in defending against the exposure to various noxious chemical substances. In this study, we reviewed magnetometric investigations of the effects of various chemicals on the lungs and AMs. Magnetometry, using magnetite as an indicator, was used to evaluate the effects of certain chemicals on the lung and AMs. A rapid decrease of the remanent magnetic field after the cessation of external magnetization, a phenomenon called relaxation, was impaired when the lungs and macrophages were exposed to toxic substances. The delayed in vivo relaxation observed in the lungs exposed to magnetite and gallium arsenide was almost identical to the in vitro relaxation observed in the AMs exposed to the same materials. Delayed relaxation was observed in the AMs exposed to silica dust; various fibers, such as chrysotile and some man-made mineral fibers; and toxic arsenic and cadmium compounds. The extracellular release of lactate dehydrogenase activity was found in the AMs exposed to the chemicals. Relaxation is attributed to the cytoskeleton-driven rotation of phagosomes containing magnetite. While the exact mechanism of delayed relaxation due to exposure to harmful chemicals remains to be clarified, cell magnetometry appears to be useful for the safety screening of chemical substances.

Meta-analysis for control study of man-made mineral fiber and patients with respiratory system tumor

目的 定量分析人造矿物纤维(man-made mineral fiber,MMMF)与呼吸系统肿瘤的关系.方法 应用Meta分析方法对MMMF与呼吸系统肿瘤的病例对照研究进行分析.统计学处理采用固定效应模型,用Q统计量进行异质性检验,用Begg's法检验发表性偏倚,并进行敏感性分析.结果 共纳入11个病例对照研究12篇文献,发表时间为1986至2008年,研究地区包括丹麦、挪威、瑞典、德国、英国、捷克、匈牙利、波兰、罗马尼亚、俄罗斯、斯洛文尼亚、加拿大和美国.未校正混杂因素的合并OR粗＝1.146(0.598～2.195),校正混杂因素后的OR_(校正)=1.30(0.75-2.24),单纯接触玻璃纤维的合并OR=1.23(0.16-9.35),单纯接触矿物棉的合并OR=1.43(0.57～3.58).结论 尚不能认为MMMF可致呼吸系统肿瘤发病风险升高,在今后的研究中需控制无差异性错误分类、混杂偏倚等的影响。