Asbestos-cement Products Research Articles

Spectroscopic Analysis of Chrysotile Asbestos and its Environmental Resistance in Asbestos Cement Waste Products

Most asbestos-related studies have focused on asbestos exposure risks, their associated health implications, and waste management issues. Our research introduced a unique perspective that has rarely been explored: the impact of environmental factors on asbestos cement products. The novelty of the study is that, in contrast to previous research, in addition to determining the material quality of asbestos, it analyses the trace materials, additives and the emissive nature of chrysotile fibers. This study aims to identify the chrysotile-asbestos content in three common asbestos cement products found in Hungary, with regard to the release of their fibers upon exposure to the environment and to identify trace elements that could be used to identify the origin and function of each of these products. Our analyses revealed the presence of chrysotile in each tested sample, with spectral matches ranging from 59.6% to 86.7%. Asbestos cement products exposed to various environmental influences for long periods showed a greater chrysotile emission capacity than those unexposed or hermetically sealed ones. Additionally, we established that all asbestos cement products contained glass fibers, with an average spectral match of 62.1%. We further identified polysilicate in the materials with an average spectral match of 66.0%, as it was included in asbestos cement products to enhance their heat resistance. Our results pave the way for a new methodology for assessing asbestos cement products with regard to the implementation of their trace element level assessments.

The impact of irrigation with harvested rainwater containing asbestos cement matrix on the germination characteristics of Solanum lycopersicum

AbstractThe study aims to investigate how the transfer of matrix materials from eroded asbestos cement products induces stress responses in plants. The paper evaluates the exposure and risk factors of plants, water, and soil to asbestos cement materials. Additionally, the experimental results provide empirical evidence for plant stress responses based on physiological and germination parameters. Contamination of irrigation water with asbestos cement raises environmental concerns due to its potential toxicity to plants and soil quality. Asbestos in irrigation water can lead to toxic stress for plants, affecting germination processes and growth. The paper analyzes the effects of preset doses of irrigation water containing asbestos cement matrix on the germination process and physiological parameters of Solanum lycopersicum in a controlled experiment setting. This research proposes methodological developments that could be valuable for environmental plant protection professionals.

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.

201 Occupational exposure of workers manufacturing chrysotile asbestos cement products: a case study in Kyrgyzstan

201 Occupational exposure of workers manufacturing chrysotile asbestos cement products: a case study in Kyrgyzstan

Asbestos Stocks and Flows Legacy in Australia

Information about asbestos stocks and flows is paramount for effective legacy management, both for understanding potential asbestos exposure risks from the different product types remaining in the built environment and proactive resource planning for their safe decommissioning, removal and disposal. This paper provides an overview of the Australian Stocks and Flows Model for Asbestos, a national model that provides best estimates to examine asbestos legacy stocks remaining in the built environment and flows to waste, now and into the future in Australia. The model was updated in 2021 to reflect new information from literature and input from industry experts and includes a Monte Carlo analysis to better reflect the range in the value estimates, as well as allowing for input of data from asbestos removal programs. Australia’s total asbestos stocks peaked at approximately 11 million tonnes in the 1980s. Over 95% of stocks comprise asbestos cement products, such as wall sheeting and water pipes. Australia’s current remaining asbestos stocks in the built environment are estimated at 6.2 million tonnes, with just under half of total consumption estimated to have gone to landfill as waste. The model can continue to be used with updated information to help track how much of Australia’s hazardous asbestos legacy is remaining and by how much it is reducing. The model can also be used to test scenarios and implications for predicted development trends and waste infrastructure needs. It is a valuable resource to assist with sustainable planning across a range of government departments that are responsible for managing asbestos waste in Australia.

Recycling of Asbestos-Cement Waste – An Opportunity or a Threat?

Abstract Asbestos-cement waste from roof coverings and facades are classified as hazardous materials and should be successively removed from buildings. The current management of these wastes is limited to their controlled depositing in landfills, which does not ultimately solve the problem of their impact on the environment in the future. The article presents the current state of disposal of asbestos in Poland, with particular emphasis on the Silesian Voivodeship. The literature reports on the methods of neutralizing this type of waste and the possibility of their recycling were analyzed. It was found that the most popular way of recycling asbestos waste is thermal treatment, and the least effective - chemical treatment. Unfortunately, legal barriers prevent the spread of these solutions in the country in practice, despite the fact that safe methods of recycling asbestos-cement products are known.

Asbestos cement products and their impact on soil contamination in relation to various sources of anthropogenic and natural asbestos pollution

The results of a quantitative analysis of asbestos content in the ground with varying degrees of concentration of this mineral as a result of natural phenomena such as rock weathering, contamination by the manufacture of asbestos and cement products, and the many years of use of “eternit roofs” are presented. Preliminary thermal treatment, soil grinding and sieving were used for the determinations, followed by electrostatic separation in order to obtain the concentration of asbestos in a smaller volume. It was used for microscopic preparations for the identification and planimetry of asbestos. A polarizing optical microscope was used in the qualitative and quantitative analysis. The levels of re-emission of asbestos dust into the air as a result of the exploitation of contaminated soil were estimated. Polluted land in industrially areas, at a distance of up to 1200 m, contains 0.0003 % to 0.02 % asbestos. The content of 0.01 % asbestos does not require remediation in the absence of soil use. It may cause <500 fibres/m3. Removing the facade of asbestos-cement panels from the building at a distance of up to 10 m resulted in concentration <0.007 % of free asbestos in the ground, and for used roofs <0.001 % from above the distance of 3 m. This means that land in the vicinity of buildings with facade or roofing made of a-c products can be safely exploited. The direct discharge of rainwater from the gutter into the ground, however, contaminates it well above this value and those places should be treated as hazardous waste due to the presence of asbestos fibres in unbound form, containing <9,8 %. Ultimately, the size of the threat depends on many factors and can be comparable with the pollution of industrial production.

Sex-Specific Mortality from Asbestos-Related Diseases, Lung and Ovarian Cancer in Municipalities with High Asbestos Consumption, Brazil, 2000-2017.

The aim of this study is to compare the mortality rates for typical asbestos-related diseases (ARD-T: mesothelioma, asbestosis, and pleural plaques) and for lung and ovarian cancer in Brazilian municipalities where asbestos mines and asbestos-cement plants had been operating (areas with high asbestos consumption, H-ASB) compared with in other municipalities. The death records for adults aged 30+ years were retrieved from multiple health information systems. In the 2000–2017 time period, age-standardized mortality rates (standard: Brazil 2010) and standardized rate ratios (SRR; H-ASB vs. others) were estimated. The SRRs for ARD-T were 2.56 for men (257 deaths in H-ASB municipalities) and 1.19 for women (136 deaths). For lung cancer, the SRRs were 1.33 for men (32,604 deaths) and 1.19 for women (20,735 deaths). The SRR for ovarian cancer was 1.34 (8446 deaths). Except for ARD-T and lung cancer in women, the SRRs were higher in municipalities that began using asbestos before 1970 than in municipalities that began utilizing asbestos from 1970 onwards. In conclusion, the mortality rates for ARD-T, and lung and ovarian cancer in municipalities with a history of asbestos mining and asbestos-cement production exceed those of the whole country. Caution is needed when interpreting the results of this ecological study. Analytical studies are necessary to document the impact of asbestos exposure on health, particularly in the future given the long latency of asbestos-related cancers.

Trends in Airborne Chrysotile Asbestos Fibre Concentrations in Asbestos Cement Manufacturing Factories in Zimbabwe from 1996 to 2016.

Zimbabwe has two major factories that have been manufacturing chrysotile asbestos cement products since the 1940s. Exposure monitoring of airborne fibres has been ongoing since the early 1990s. This study examines trends in personal exposure chrysotile asbestos fibre concentrations for the period 1996–2016. Close to 3000 historical personal exposure measurements extracted from paper records in the two factories were analysed for trends in exposure. Exposure over time was characterised according to three time periods and calendar years. Mean personal exposure chrysotile asbestos fibre concentrations generally showed a downward trend over the years in both factories. Exposure data showed that over the observed period 57% and 50% of mean personal exposure chrysotile asbestos fibre concentrations in the Harare and Bulawayo factories, respectively, were above the OEL, with overexposure being exhibited before 2008. Overall, personal exposure asbestos fibre concentrations in the factories dropped from 0.15 f/mL in 1996 to 0.05–0.06 f/mL in 2016—a decrease of 60–67%. These results can be used in future epidemiological studies, and in predicting the occurrence of asbestos-related diseases in Zimbabwe.

Sidorsky deposit of construction sands in the Volgograd region

Relevance of the research. Construction sands are the largest functional group of sands widely used in construction industry. This natural material is one of the most demanded for the production of manufactured products in the construction industry of the region. Purpose of the researchis to study the engineering-geological conditions of construction sands deposit for the production of the manufactured products of OAO Sebryakovsky plant of asbestos-cement products, as well as for construction organizations of the region. Research methods. Based on the analysis of extensive collection materials using laboratory and statistical methods, as well as the results of additional research, the physical-geographical, engineering-geological and technogenic conditions of the study area were examined. Results and their application. The useful stratum of the deposit is composed of Upper Quaternary alluvial sands, the average thickness of which is 8.6 m, penetrated thickness is up to 12.3 m. Overburden within the study area is represented by the soil-vegetation horizon – up to 0.2 m. The extracted raw materials are used in the production of mortars, which is confirmed by tests of a cement-sand grout, and as a filler in fine-grained concrete. The reserves of the deposit are calculated in categories A + B + C1 in the amount of 2313.2 thousand m3. The development of the deposit is recommended by the open method. Explored and recoverable reserves will ensure the operation of the enterprise with an annual demand of 100 thousand m3 per year for a period up to 2030. Conclusions. Based on the results of the studies, it should be noted that the Sidorsky deposit of construction sands is assessed as profitable and competitive in relation to the exploited deposits of sand in the Volgograd region.

The effective air exchange organization scheme selection in the working area at the asbestos-cement products manufacturing enterprises

The article explores various schemes of air exchange organizing in the molding shop of an enterprise for the asbestos-cement product’s manufacturing. To find the air exchange value, a system of balance equations for the workshop and the working area is proposed and solved, characterizing coefficients are determined. Based on the data on the disperse composition of dust and aerodynamic characteristics, the optimal air exchange scheme for the enterprises producing building materials is proposed.

Determination of the aspiration air consumption from equipment at the enterprises for the asbestos-cement products’ manufacturing

The authors refined the calculation model of dust distribution in the working air flow areas and zones from several sources for the enterprises producing chrysotile asbestos and cement products using a mathematical apparatus. Erasing these patterns, pilot studies of the aspiration volumes values from the enterprise molding workshop technological equipment were carried out. The amount dependences of the dust emission and the dust concentration in the air of the working zone on the aspiration air flow rates for the overflow unit were revealed. The optimal values of the specified parameters necessary to achieve the maximum permissible concentration of chrysotile asbestos dust in the working area air in the building materials’ production are determined.

Characterization of Demolition Construction Waste Containing Asbestos, and the Release of Fibrous Dust Particles

This paper focuses on the characterization of demolition construction waste containing asbestos fibers and the monitoring of fibrous dust released from asbestos–cement products (ACPs) during their removal from a three-story industrial building. Asbestos-containing products removal was carried out according to a demolition management system in terms of protection of workers. The results of a chemical analysis, X-ray diffraction analysis, infrared analysis and scanning electron microscopy of demolition waste samples confirmed the same material quality of asbestos–cement (AC) elements used throughout the building. In addition, a MgO/SiO2 ratio corresponding to a serpentine silicate mineral of chrysotile was detected by means of X-ray fluorescence analysis. Also, crystalline phase calcium silicates and calcium carbonates from the cement matrix were identified in the AC waste. The relatively large differences in the elemental analysis between the sample area and the individual points found by energy-dispersive X-ray spectroscopic mapping are related to the composition heterogeneity. The highest content of magnesium occurs where asbestos fibers predominate in the cement matrix. The measured number concentrations of asbestos fibers before, during, and after asbestos–cement products removal were compared to outdoor concentrations. Indoor concentrations of asbestos fibers during the removal of AC materials did not exceed the permissible limit for a working environment (1000 fibers per one m3), except in three spots out of all the working sites inside the building. A relationship between the number and mass concentrations of asbestos dust is shown.

Level of occupational health risk for workers exposed to aerosols containing chrysotile asbestos

Introduction. The presence of asbestos-containing aerosols in the workplace is one of the main occupational carcinogenic risks in the world. In view of the absence of registered cases of occupational diseases related to exposure to asbestos dust in the Republic of Belarus, it is relevant to study morbidity with temporary disability and to assess occupational health risks using these data. The aim of the study is to determine the characteristics of the dynamics and structure of the morbidity with temporary disability and the assessment of occupational health risks for workers exposed to aerosols containing chrysotile in the building materials manufacturing. Materials and methods . The studies were carried out on the basis of a workshop for the production of asbestos-cement products based on chrysotile. An in-depth analysis of the morbidity with temporary disability was conducted over a four-year period. The influence of the gender, age, and experience composition of groups on the levels of the morbidity with temporary disability was evaluated using standardized indicators. The assessment of the production conditionality of morbidity was carried out in a comparative analysis with the control group (workshop for the production of blocks made of cellular concrete and composite materials), national indicators and indicators of the construction materials industry. The risk assessment was carried out using the occupational risk index calculated based on the relative risk index and the total coefficient of working conditions. Results. The dynamics of the overall intensive indicators of morbidity with temporary disability in the study group shows a tendency to decrease due to a decrease in labor losses in the class of “Respiratory Diseases”, however, the duration of 1 case increases. The overall average long-term indicators of temporary disability are significantly higher in the control group. However, the incidence rates for the class of endocrine diseases, diseases of the circulatory system and diseases of the digestive system are significantly higher in the study group. The average long-term morbidity rates of the study group do not have statistically significant differences with national and industry indicators. Standardization of general indicators of morbidity by gender, age and experience does not change their ratio, but the incidence rates differ in different age, experience and gender groups. The occupational risk index for employees of the asbestos cement products workshop is estimated as average, and the level of occupational health losses of employees is 33.7% (significant, class 3) in the study group and 45.7% (high, class 4) in the control group. Conclusions. Morbidity with temporary disability of workers exposed to chrysotile asbestos dust does not differ significantly from the national and industry levels, and in comparison with the control group shows lower indicators; the level of occupational health risk of workers exposed to chrysotile asbestos is significant; the highest incidence rates are registered in young and least trained employees of the workshop of asbestos — cement products, and by gender-in men, which should be taken into account when planning preventive measures.

Asbestos exposure and haematological malignancies: a Danish cohort study

Environmental asbestos exposure and occupational asbestos exposure increase the risk of several types of cancer, but the role of such exposures for haematological malignancies remains controversial. We aimed to examine the risk of haematological malignancies: first, in subjects exposed early in life, independently of any occupational exposure occurring later; second, in subjects exposed occupationally. We established an environmentally exposed cohort from four schools located near the only former asbestos cement production plant in Denmark. We identified nearly all pupils in the seventh grade and created an age and sex-matched 1:9 reference cohort from the Danish Central Population Register. Participants were born 1940–1970 and followed up in national registers until the end of 2015. Occupational asbestos exposure was assessed for all participants using two different job exposure matrices. The school cohort included 12,111 participants (49.7% girls) and the reference cohort 108,987 participants. Eight subgroups of haematological malignancy were identified in the Danish Cancer Registry. These cases were analysed for combined overall haematological malignancy, a combined subgroup of lymphomas and a combined subgroup of leukaemias. The data were analysed using Cox regression (hazard ratios (HR)) including other cancers and death as competing risks. Haematological malignancy was identified in 1125 participants. The median follow-up was 49.3 years (0.1–63.4). Early environmental asbestos exposure was not associated with an increased risk of haematological malignancy. Long-term occupational asbestos exposure was associated with overall haematological malignancy (HR 1.69, 95% CI 1.04–2.73); in particular for the leukaemia subgroup (HR 2.14, 95% CI 1.19–3.84). This large follow-up study suggests that long-term occupational asbestos exposure is associated with increased leukaemia risk. However, further studies are needed to confirm these observations.

Asbestos—Cement Roofing Identification Using Remote Sensing and Convolutional Neural Networks (CNNs)

Due to the pathogenic nature of asbestos, a statutory ban on asbestos-containing products has been in place in Poland since 1997. In order to protect human health and the environment, it is crucial to estimate the quantity of asbestos–cement products in use. It has been evaluated that about 90% of them are roof coverings. Different methods are used to estimate the amount of asbestos–cement products, such as the use of indicators, field inventory, remote sensing data, and multi- and hyperspectral images; the latter are used for relatively small areas. Other methods are sought for the reliable estimation of the quantity of asbestos-containing products, as well as their spatial distribution. The objective of this paper is to present the use of convolutional neural networks for the identification of asbestos–cement roofing on aerial photographs in natural color (RGB) and color infrared (CIR) compositions. The study was conducted for the Chęciny commune. Aerial photographs, each with the spatial resolution of 25 cm in RGB and CIR compositions, were used, and field studies were conducted to verify data and to develop a database for Convolutional Neural Networks (CNNs) training. Network training was carried out using the TensorFlow and R-Keras libraries in the R programming environment. The classification was carried out using a convolutional neural network consisting of two convolutional blocks, a spatial dropout layer, and two blocks of fully connected perceptrons. Asbestos–cement roofing products were classified with the producer’s accuracy of 89% and overall accuracy of 87% and 89%, depending on the image composition used. Attempts have been made at the identification of asbestos–cement roofing. They focus primarily on the use of hyperspectral data and multispectral imagery. The following classification algorithms were usually employed: Spectral Angle Mapper, Support Vector Machine, object classification, Spectral Feature Fitting, and decision trees. Previous studies undertaken by other researchers showed that low spectral resolution only allowed for a rough classification of roofing materials. The use of one coherent method would allow data comparison between regions. Determining the amount of asbestos–cement products in use is important for assessing environmental exposure to asbestos fibres, determining patterns of disease, and ultimately modelling potential solutions to counteract threats.

About the technological equipment tightness evaluation method in asbestos-cement products manufacturing

The technological equipment evaluation method as a dust emission source, adapted for the asbestos-cement production field is presented. An example of determining the process equipment tightness and calculating the dust emissions amount in the stocking plant workshop for the asbestos-cement products manufacturing is given. It made it possible to identify the sources of the highest dust emissions, to evaluate the quality of functioning of the used means of air purification of the working area, the harmful substances maximum permissible concentration excess level. The recommendations to reduce the negative impact of the dust factor in the enterprise working areas air are given.

Application of theoretical studies for a description of the process of dust subsidence of chrysotile-asbestos dust and cement dust

The authors have sampled dust samples in the modelling shop of the enterprise, that produced asbestos cement products, performed the dispersal analysis of chrysotile asbestos dust and cement dust, built areas of integral curves particle mass distribution by diameters for aspiration systems, general exhaust ventilation and sanitary protection zone. For description of dispersal composition of dust were used two-link splines in log-probabilistic coordinate system. Carried out a mathematical evaluation of these functions as random. The method of "dissection" is used for their description.

The Wittenoom legacy.

The Wittenoom crocidolite (blue asbestos) mine and mill ceased operating in 1966. The impact of this industry on asbestos-related disease in Western Australia has been immense. Use of the employment records of the Australian Blue Asbestos Company and records of the Wittenoom township residents has permitted two cohorts of people with virtually exclusive exposure to crocidolite to be assembled and studied. Follow-up of these two cohorts has been conducted through data linkage with available hospital, mortality and cancer records. The evolution of asbestos-related disease has been recorded and, with the establishment of exposure measurements, quantitative exposure-response relationships have been estimated. There has been an ongoing epidemic of mortality from lung cancer and malignant mesothelioma and, less so, from asbestosis. Wittenoom crocidolite was used extensively in asbestos-cement products in Western Australia. As a result, the state has recorded a higher malignant-mesothelioma mortality rate than in any other Australian state and in any defined general population in the world. Thus, the legacy of Wittenoom has extended beyond the mine and the town, and is still evident more than 50 years after the closure of the mine.

Simultaneous treatment of agro-food and asbestos-cement waste by the combination of dark fermentation and hydrothermal processes

The inadequate management of asbestos-cement products (ACP) and/or wastes (ACW) generates hazardous airborne dusts. For this reason, the EU is promoting the removal of ACP from utilities, public and private buildings and is looking for innovative ACW treatments alternative to the landfilling. The simultaneous treatment of ACW and orange pulp or cheese whey was attempted with a mesophilic dark fermentation (DF) process followed by a 12 h hydrothermal (HT) treatment carried out with the addition of lactic or oxalic acid at 100 °C and ambient pressure. The DF of orange pulp or cheese whey in the presence of 5 g L−1 ACW lasted 171 h and led to the production of 4 LH2 and 5 LH2 per litre of solution, respectively. During the DF, the dissolution of the ACW matrix was almost completed, and the partial collapse of the asbestos fibres was observed. Both the organic acids that were added during the HT tests at a concentration ≥2.5 g L−1 completely destroyed the asbestos fibres. However, when 1.25 g L−1 lactic or oxalic acid was added before the HT tests, few fibre fragments were found, and their chemical composition differed from that of chrysotile.