Abstract
Asbestos still represents a major public health problem on a global scale. In Central Asia chrysotile is still mined and used, claiming that it is safer with respect to amphibole asbestos within certain concentrations. However, the problem of asbestos exposure in Central Asia and its consequences on human health have been poorly investigated. We analysed, for the first time, samples of raw and wrought material coming from one of the two asbestos-cement industries, currently active, located near the city of Bishkek, the capital of Kyrgyzstan, as well as air samples collected on different sites of Bishkek and Kant and lung tissues taken from the general population during clinical autopsies. Air samples have been analyzed using a scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). Heavy air asbestos pollution was detected in Kant (30.2 ff/L), while Bishkek had lower levels. Lung tissue analysis in the general population, carried out using both SEM and transmission electron microscopy (TEM) with EDS, revealed the presence of both chrysotile and amphibole asbestos. Such findings underline that, even in countries where the use of asbestos is allowed based on the presumed pureness of chrysotile used and the lower carcinogenic potential of chrysotile compared to amphibole asbestos, the general population could be exposed also to amphibole asbestos.
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Introduction
The term ‘asbestos’ is a broad industrial designation that lacks precise scientific definition and refers to six distinct minerals:: chrysotile, crocidolite, amosite, anthophyllite asbestos, tremolite asbestos, and actinolite asbestos1,2,3,4,5,6. From a mineralogical standpoint, chrysotile belongs to the serpentine group, while the other minerals are classified as amphiboles3. At the microscopic level of investigation, amphibole asbestos has an elongated prismatic habit, parallel-sided, with cleavages that intersect at about 60°and 120°; whereas chrysotile consists of long, thin, and flexible crystals characterized by uniform width, occurring either as single fibrils or as bundles and aggregates7. Both chrysotile and amphibole asbestos morphologies resembles of textile fibres and these crystals are usually named “fibres”. The scientific and commercial sectors use different definitions for the term ‘fiber.’ The WHO defines a ‘critical fiber’ as one with a length of at least 5 µm, a diameter of no more than 3 µm, and a length-to-diameter ratio of at least 38. The Italian law9,10 defines “respirable fibres” as fibres longer than 5 µm, thinner than 3 µm, having a length/diameter ratio greater than 3. Inorganic fibers that meet these size criteria are collectively referred to as ‘regulated fibers.’ A ‘bundle’ refers to a group of closely linked fibers aligned in parallel.
Chrysotile generally exhibits lower biopersistence than amphibole asbestos11,12. This is mainly because its magnesium and hydroxyl-containing structural sheet dissolves when exposed to the lung environment13,14.
Loss of the magnesium-rich structural sheet compromises chrysotile’s structure, causing the fiber to break down into smaller fibrils and residual material that can be phagocytosed by macrophages and cleared from the alveoli1. It is well known that the retention of chrysotile in human lungs is much lower compared to that of amphiboles, due to its rapid clearance, rather than a lower rate of deposition15. Evidence in the literature suggests that chrysotile has lower carcinogenic potency in humans compared to amphibole asbestos, likely due to its faster clearance from the lungs7,16,17. Yet, several epidemiological studies have shown a clear association between chrysotile exposure and the development of mesothelioma and lung cancer18,19,20. However, the above-cited studies deal with cohorts with long-term exposure to dust containing chrysotile fibres at high concentrations, as do other similar studies21.
Chrysotile, crocidolite, amosite and, to a lesser extent, anthophyllite asbestos, were largely used by different manufacturers and for commercial purposes. Conversely, tremolite asbestos and actinolite asbestos were never used commercially, but they do occur abundantly in several mineral deposits worldwide and are used as ornamental stones and railway ballast. Tremolite asbestos and actinolite asbestos are particularly abundant in serpentinite rocks as the main mineral in rock veins or as accessory minerals and they can be present as contaminants in other rocks where the mined mineral is vermiculite or talc22,23.
All forms of asbestos are widespread in the Earth’s crust, occurring both as impurities in minerals such as chrysotile and talc, and as components of independent ore bodies. Natural processes can release asbestos fibers from these sources into the air, meaning asbestos has been present in the human environment long before industrial use and will persist even after its complete phase-out24. Considering the amphibolic contamination of some chrysotile ores25,26,27 some authors suggested that the increased risk of developing mesothelioma after chrysotile exposure is due to the tremolite asbestos contamination of the chrysotile ore rather than the chrysotile by itself (“amphibole hypothesis”)28. As noted in the literature5even if the debated amphibole hypothesis29,30 is correct, chrysotile could also contribute to toxicity by promoting the uptake of smaller, reactive oxygen species (ROS)-inducing particles. This mechanism, however, requires further confirmation through in vivo studies and epidemiological research31.
Nevertheless, the World Health Organization (WHO) and the International Agency for Research on Cancer (IARC) have classified all types of asbestos as Group I carcinogens32. However, the debate regarding the possible lower carcinogenic potential of chrysotile compared to amphibole asbestos is ongoing, as well as the possible lower risk of developing mesothelioma and lung cancer after exposure to pure chrysotile compared to amphiboles7,16,33,34.
In May 2007, the 60th World Health Assembly endorsed “a global plan of action on workers’ health” to be implemented in 2008–2017 including “global campaigns for the elimination of asbestos-related diseases – bearing in mind a differentiated approach to regulating its various forms – in line with relevant international legal instruments and the latest evidence for effective interventions”35;
Prior to this, some countries had already banned asbestos, while others followed the WHO’s recommendation. Up to now, 72 countries have banned asbestos, and others (e.g. the U.S.) have stringent regulations36. However, chrysotile is still used and traded in several countries. Nowadays the world leaders in asbestos production are Russia, China, Kazakhstan and India. In particular, Russia and Kazakhstan are still mining chrysotile, and the neighbouring countries (especially Uzbekistan, Kyrgyzstan, and Tajikistan) are still chrysotile consumers. According to the WHO estimates, on a global scale, more than 125 million people are exposed to asbestos annually while working, with a high percentage of them residing in countries that have not implemented an asbestos ban. The global death toll related to asbestos exposure is around 255,000 deaths per year37 as estimated by a joint study performed by WHO and ILO38. However, many authors consider these and other forecasts by the WHO and ILO to lack accuracy39,40,41. It is important to highlight that the asbestos exposure is still ongoing also in countries which banned its use, because of the diffused presence of asbestos-containing materials (ACM) previously installed in buildings and machinery42. Obviously, the levels of exposure and the number of exposed subjects are higher in the countries which did not join the global ban. In such countries, the main argument raised to justify the decision to continue to mine and use asbestos is that they handle only chrysotile, considered less hazardous with respect to mesothelioma and lung cancer causation than amphibole asbestos. Moreover, the pathogenic effect of chrysotile is believed to be related to the inhalation of higher doses compared to amphibole asbestos43.
Accordingly, Russia, like many other countries, has banned amphibole asbestos44. However, some authors argue that vested interests have influenced the literature on chrysotile, which remains the most widely available and used form of asbestos globally45. While the causal relationship between amphibole asbestos and mesothelioma and lung cancer is well-established, several questions regarding the actual health risks of chrysotile alone remain unresolved46.
The topic of asbestos mined and used in Central Asia (CA) and its mineralogical identity has been scarcely investigated47 but Public Health authorities in such countries claim the exploited asbestos is pure chrysotile45,48,49. Unfortunately, data from Central Asia are limited, and the few available studies use differing methodologies, making comparisons difficult, as highlighted in a recent review by our group47.
On this basis, it is evident that there is an important gap in scientific knowledge about the type of asbestos mined and used in CA. The main unresolved questions are whether the asbestos used is pure chrysotile or contaminated with amphibole asbestos, the extent of asbestos air pollution in Central Asian cities, and the amount of asbestos inhaled by residents.
To shed light on the above-mentioned aspects, we carried out this study in one of the CA countries, Kyrgyzstan, where two plants produce chrysotile cement products. Both plants are located in the area of Kant town of the Chui Valley, 22 km to the northeast of the capital city Bishkek. The two plants started the manufacture of chrysotile-cement products respectively in 1967 and 2013, and both currently produce chrysotile cement pipes, chrysotile-cement roofing sheets, fibre cement flat boards, fibre cement siding, and cement sand roof tiles. Since the foundation of these two plants, the produced ACM have been well spread and used all over Kyrgyzstan and exported to the surrounding countries (in particular, Uzbekistan and Tajikistan50), particularly in the building sector50.
This study has three aims:
1) to clarify the mineralogical nature of asbestos used in Kyrgyzstan;
2) to investigate the presence and amount of airborne asbestos in Bishkek, the capital city of Kyrgyzstan, and Kant town;
3) to investigate the asbestos lung burden of the general population of Bishkek, the capital city of Kyrgyzstan.
Methods
In this study, we analyzed three types of samples: raw and processed materials, air samples, and lung tissue. Raw and processed materials were examined using stereomicroscopy, powder X-ray diffraction (PXRD), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), and transmission electron microscopy with EDS (TEM-EDS). Air samples were analyzed with SEM-EDS, while lung samples were examined using both SEM-EDS and TEM-EDS.
Raw and wrought materials
The materials have been collected at Plant 1 in July 2022, located in the town of Kant (Table 1).
Stereomicroscopy
Samples were first examined with a stereomicroscope (Star Novel - Trilus) to assess the presence, approximate quantity, and characteristics of visible fiber bundles.
SEM–EDS
For SEM-EDS analysis, small fragments of solid samples and small amounts of powder were mounted on aluminum stubs using double-sided carbon tape (Media System Lab, Macherio, Italy), then coated with carbon (JEOL - IEC 530-108CA-JE6251) to ensure conductivity. SEM imaging and EDS chemical analyses were performed using two instruments: Scanning Electron Microscope JEOL JSM IT300LV equipped with EDS Oxford INCA Energy 200 microanalysis having an INCA X-act SDD thin window detector.
Powder X-ray diffraction (PXRD)
The samples were prepared for PXRD analysis by hand-grinding in acetone to avoid the dispersion of particles. Once dried, the sample was mixed with a glycerin oil to avoid particle dispersion during manipulation and analyses. The glycerin oil-particles mix was placed in an Al holder for PXRD analyses. The PXRD data were collected on the sample using a Miniflex 600 diffractometer (Rigaku, Tokyo, Japan) equipped with a Cu–Kα1 radiation source (λ = 1.54055 Å, 40 mA, 45 kV), fixed divergence slits, and a multistrip D/TEX Ultra detector with a resolution of < 200 eV. A divergent slit width of 2 mm and a scatter-slit width of 4 mm were used for the incoming beam, whereas a receiving slit width of 0.5 mm and scatter-slit width of 0.2 mm were used for the diffracted beam. Data were collected in step-scan mode in the 3 ° − 70 ° 2θ range, with a step size of 0.02° 2θ, and a counting time of 2 s per step. To reduce the fluorescence contribution to the background, the detector multistrip D/tex was added, with the function “XRF Reduction”.
Transmission electron microscope combined with an energy-dispersive spectrometer (TEM–EDS)
Samples for TEM-EDS were hand-ground in 2-propanol using an agate mortar and pestle. The resulting suspension was transferred to a Falcon tube and sonicated for 10 min to disperse particle aggregates and achieve a uniform suspension. A drop of the suspension was then transferred on a TEM holey C and Cu grid. Morphological, structural and chemical features were examined by a TEM Philips CM12 (Philips, Amsterdam, The Netherlands), working at 120 kV and equipped with an energy dispersive spectrometer EDAX Genesis 2000 System, managed by the TEM Quant Software PV8206/31 (Pleasanton, CA, USA). The Cu grids were loaded on a double-tilt holder. The particles of interest, when present, were investigated in medium and high magnification, and Select Area Electron Diffraction (SAED) patterns were collected to verify the crystallinity and the identity of the observed mineralogical phases together with the chemical data obtained by EDS.
Air samples
Air samples were collected in both Bishkek and Kant (see Table 2; Figs. 1 and 2). In Bishkek, four samples were taken from residential areas in the northern, western, southeastern, and central parts of the city. In Kant, three samples were collected near the asbestos-cement plants. All the samplings were performed in July 2023, during 4 sampling days. Each sampling lasted about 8 h (from 460 to 582 min) and air sample volumes ranged from 0,927 to 1,178 m3.
(a) Location of each air sampling in Bishkek City; https://www.maps.google.com (b) Wind Roses of Bishkek City on July 1–31, 2023, https://power.larc.nasa.gov/data-access-viewer/).
(a) Location of each air sampling performed in Kant town; https://www.maps.google.com (b) Wind Rose of Kant Town on July 1–31, 2023 (https://power.larc.nasa.gov/data-access-viewer/).
Sampling followed ISO 14966:2019 and ISO 13794:2019 standards51,52. Airborne asbestos fibers were collected on polycarbonate filters (25 mm diameter, 0.8 μm porosity; Merck KGaA, Darmstadt, Germany) using a sampling head with a cylindrical cowl and filter holder, attached to an SKC AirChek XR 5000 sampler (flow rate: 2 L/min). All samplers were calibrated during the pre-sampling phase (± 5% of the nominal flow) and the flows were checked at the end of each sampling session, verifying that the maximum variation in the pre- and post-sampling flow was not > 5%. The sampling systems were arranged on tripod stands, and placed on fixed stations at the locations described in Table 2, with the sampling heads 1.5 m above ground level.
The determination of the concentration of airborne asbestos fibres (expressed in number of fibres per litre of air: ff/L) in the atmosphere was carried out following the indications of the Italian Ministerial Decree 06/09/1994 (Annex 2B)53 and the ISO 13794:201951. The analyses of the collected air samples were carried out using a SEM (XL30 ESEM – FEG, Philips; 400 microscopic fields investigated for each sample at 2000x; Working voltage: 20 KeV; Working distance: 15 mm) equipped with an energy dispersive spectrometer (EDAX, Quantax 400, Bruker Karlsruhe, Germany) for the compositional analysis of each fibre, to classify the fibres according to their chemical composition. The criteria for fibre counting are those defined as per Italian Ministerial Decree 06/09/1994 (Annex 2B) including the definition of “respirable fibres” (based on the following dimensional characteristics: length ≥ 5 μm, diameter ≤ 3 μm, length/diameter ratio ≥ 3).
Before carrying out the analysis, each filter was placed on a 25 mm Al stub and coated with a thin (10 nm) layer of gold (three depositions; 20 s at 20 mA each - Cressington 108 auto Sputter Coater), in order to make the sample conductive. The numerical concentrations of asbestos fibres were calculated using the following relationship:
Where:
-
number of fibres counted (ff): are the fibres counted on the filter;
-
number of fields counted: these are the fields observed for each count;
-
Microscopic field area (mm2): surface of the microscopic field, which corresponds to 0.00262 mm2;
-
Effective filter surface (mm2): inspectable filter surface which corresponds to 283 mm2;
-
Normalized Volume (L): sampling volume corrected for the temperature detected at the time of calibration and sampling.
Lower and upper confidence limits were calculated, with 95% probability, assuming a Poisson random distribution of the fibres on the sampling membrane. The limit of detection (LOD) of this analytical technique corresponds to the upper confidence limit calculated based on the Poisson distribution with 95% confidence interval (CI) and depends on the number of fibres detected, the number of microscopic fields observed and the sampled volumes.
Lung tissue
Lung samples were taken from the inferior lobe of the right lung in 100 consecutive autopsies performed at the Republican Bureau of Pathological Anatomy of Kyrgyz Republic in 2021.
SEM-EDS
In this study 30 of those samples were investigated using SEM-EDS (JEOL JSM IT300LV coupled with microanalysis EDS Oxford INCA Energy 200 equipped with INCA X-act SDD thin window detector), according to the protocol by Belluso et al.54. In brief, the method consists by the chemical digestion (using 13% sodium hypochlorite) of 0.25 g of formalin-fixed lung tissue (to degrade the organic materials), filtration of the suspension through a mixed cellulose esters membrane (Merck KGaA, Darmstadt, Germany) with a diameter of 25 mm and a pore size of 0.45 μm. The filters were then attached on a pin-stub using a carbon tape (Media System Lab, Macherio, Italy), and examined by SEM-EDS. The SEM-EDS investigations were performed on an area of 2 mm2 of filter at 4,000 X using both secondary (SE) and backscattered electrons (BSE). In this study, we considered all particles with an aspect ratio greater than 3:1, including those that do not strictly meet the definition of fibers as outlined by relevant guidelines and legislation8,9,10. However, we have kept “regulated fibers” distinct from “short fibers” (those shorter than 5 μm) in our dataset to better understand potential differences in the concentrations of short versus regulated fibers.The inorganic fibres and asbestos bodies (ABs) were counted (then expressed in terms of fibres and ABs per gram of dry weight - ff/gdw and ABs/gdw, respectively), measured, and the fibre chemical composition was recorded.
TEM-EDS
A subgroup of the lung samples observed by SEM were also prepared for TEM-EDS. Samples were digested and prepared for TEM analyses using a gentle bleach method6,55. The TEM grid was mounted on the holder together with a Be ring to improve the sample stability when exposed to the electron beam. The loaded double-tilt sample holder was left in the TEM column for 30 min before starting the exposure to the electron beam to reduce beam damage56,57.
The TEM-EDS investigations were conducted using an acSTEM, model ARM 200 CF equipped with a high-brightness cold-field emission gun (CFEG) operating at 80 kV, and an EDS system (Centurio 100 mm2, JEOL). A spot size 3 to 5 and a relatively low voltage (80 kV) were used to further reduce the beam damages to the sample58.
Ethical aspects
The study was approved by the Ethics Committee of the Scientific Production Association ‘Preventive Medicine’ of the Kyrgyz Republic’s Ministry of Health on June 30, 2022. We used archived autopsy samples originally collected for diagnostic (routine histology) purposes from deceased individuals. Informed consent was given by the local government. All procedures complied with the Helsinki Declaration and national regulations.
Results
Raw and wrought materials
Stereomicroscopic observation
The samples have been first examined morphologically under a stereomicroscope, showing mostly white, flexible fiber bundles. The appearance of each sample is described in Table 1.
SEM-EDS
In sample C no fibres were detected. In the other 5 samples, fibre bundles were observed. In all samples, the bundles appear curved and sometimes folded, with different widths, and are very long (no less than 1 mm). The chemical composition is constant and consists mainly of O, Mg and Si; sometimes a very small amount of Al and/or Fe is present. In all the above-listed samples, the observed fibres were identified as chrysotile or asbestiform antigorite (Fig. 3), given the impossibility of univocally distinguishing asbestiform antigorite from chrysotile asbestos on the basis of morphological, dimensional, and chemical characteristics detectable by SEM-EDS. The certain identification will be obtained by TEM-EDS and SAED investigation detailed below.
Secondary electrons SEM images (a) and EDS spectra (b) of sample 6_45.
In wrought materials, calcium present is ascribable to the composition of cement particles.
PXRD
The PXRD spectra show the presence of chrysotile in samples HC, 5_50, 6_45, ACM1 and ACM2 (Fig. 4). Carbonates (e.g. dolomite), sulphates (e.g. gypsum) and periclase were found in samples HC and C. Samples ACM1 and ACM2 spectra (Supplementary Information) display larger humps and higher background noise levels than samples “C”, “HC”, “5_50”, and “6_45”. The humps and high background noise are probably related to higher concentrations of glycerine oil-based hand cream that was used in certain samples, and the small and heterogeneous amount of sample analyzed. Asbestos phases were not detected in PXRD spectrum of sample C (Supplementary Information).
PXRD spectrum of the sample “6_45” correspondent to the chrysotile JCPDS ID card 00-002-0350.
TEM-EDS and SAED
The loose white dust samples (5_50 and 6_45) were identified as chrysotile by TEM-EDS and SAED investigations (Figs. 5 and 6). For all the investigated fibres, the SAED is analogous to that shown in Fig. 5b. The typical inner channel of chrysotile, due to its secondary structure, is shown by the arrow in Fig. 6a. On the contrary, on sample C chrysotile was not detected (not shown). In the sample HC a predominance of chrysotile fibrils was observed. One of the fibrils showed a straight shape and a SAED compatible, but not confirmed as an amphibole structure (Fig. 7). Chrysotile fibrils were detected in both the samples ACM1 (Supplementary information) and ACM2 (Fig. 8). In particular, in ACM2 we highlighted the presence of connective material between bundles (Fig. 8), and a higher presence of Ca with respect to other samples (Fig. 8).
(a) Low-resolution bright field (BF) image of chrysotile fibrils in sample 5_50, (b) the related SAED, and (c) the EDS spectrum collected on a single fibril.
(a) Low-resolution bright field (BF) image of an individual chrysotile fibril detected in sample 6_45 in which the chrysotile inner channel is visible (red arrow), (b) the related SAED, and (c) the EDS spectrum collected on the same fibril.
(a) Low-resolution BF image of chrysotile fibrils detected in sample “HC” in which an amphibolic fibre might be present (red arrow), (b) the SAED collected on the fibre highlighted in (a), and (c) the EDS spectrum collected on the same fibre.
(a) Low-resolution BF image of chrysotile fibrils detected in sample “ACM2”, (b) the EDS spectrum collected on a single fibre.
Air samples
The results of the air sample analysis are summarized in Table 3. Samples labeled as K20 and K22 (collected, respectively, at the city centre and in the northern part of the city) showed asbestos concentrations below the limit of detection (LOD). K19 and K_blk_1, collected in Bishkek (respectively, South-East and West with respect to the city centre) showed 0.9 ff/L (Fig. 1).
K21, K23 and K24 were collected in Kant town, where the two plants producing asbestos-cement artifacts are located (Fig. 2). K21 and K23, collected 500 m and 1 km far from plant 2 (Fig. 2) showed high concentrations of chrysotile, namely 30,2 ff/L and 9,6 ff/L. K24, collected 1 km away from plant 1 (Fig. 2) showed 1.2 ff/L.
Lung tissue
SEM-EDS analysis on lung samples
Among the 100 available lung tissue samples, a subgroup of 30 was randomly selected for examination under SEM-EDS (14 males, 16 females) (Table 4). The mean age was 64.8. Regarding the location of residency, 13 of them used to live in Bishkek city, while 7 used to live in the surrounding villages and 5 people lived outside Bishkek and Alamudun regions. Four of them lived in Kant town, where the two asbestos plants are located. In one case the residency address was unavailable. Regarding occupation, 15 subjects were retired at the moment of death (the previous occupation was not known), 3 were disabled people who never worked and 3 were unemployed. Among the employed subjects, one was an accountant, and one was a farm worker. The complete occupational history remains unclear, making it uncertain whether they were occupationally exposed to asbestos or not. All of them died from natural causes (heart failure or respiratory failure due to pneumonia). After performing SEM-EDS analysis, two samples (1 and 15) had to be excluded from the study because the samples were unreadable despite the preparation being repeated three times. The SEM-EDS analysis (Table 5), revealed inorganic fibres in 22 out of 28 samples. In 17 subjects regulated inorganic fibres were detected. The most commonly detected were titanium dioxide, feldspars and phyllosilicates. The highest concentration of regulated inorganic fibres was 31952 ff/gdw, while the mean was 8154 ff/gdw (SD = 9192.63). Fibres attributable to asbestos were detected in 3 out of 28 samples (5, 8 and 100). In sample 5 and 8, respectively, 4565 and 7861 ff/gdw have been detected, and classified as tremolite/actinolite asbestos according to the EDS spectra and morphology. In sample 100 one amosite fibre was detected (corresponding to 4288 ff/gdw). The mean length of detected asbestos fibres was 9.2 μm, while the mean width was 0.9 μm. ABs were detected in 3 subjects: 7, 42 and 47 (respectively, 3451, 2670 and 4043 ABs/gdw were found). In four of the 28 samples (6, 18, 30, 33), only inorganic fibers shorter than 5 μm were detected, identified as phyllosilicates, titanium dioxide, or feldspars. In samples 36 and 8, one and two fibers, respectively, were observed with EDS spectra compatible with tremolite/actinolite composition; however, since these fibers were shorter than 5 μm, they are not classified as asbestos under current regulations)9,10. In sample 42, as the fibre forming the ABs was not totally covered, the EDS analysis was feasible, revealing an EDS spectra typical of amosite.
TEM-EDS analysis on lung tissue
The four samples marked with a star in Table 5 were analyzed by TEM-EDS. Fibrils with inner channels were observed in samples 28, 64, and 72 (Fig. 9). These fibrils were consistently surrounded by biological material and showed signs of dissolution, such as rounded edges and amorphization. Chemical analysis consistently revealed silicon and oxygen, with magnesium present in sample 28 but apparently depleted in samples 64 and 72. The typical ‘bubble shapes’ indicative of beam damage in chrysotile fibrils were absent. Due to the poor visibility of SAED patterns, a definitive identification was not possible; thus, the particle in sample 28 was classified as chrysotile, while those in samples 64 and 72 were most likely, but not definitively, Mg-depleted chrysotile.
(a) A bright field (BF) TEM image showing a fibril (red arrow) partially surrounded by biological material retrieved in the sample 28. The highlighted ROI (red square) highlights the presence of an inner-channel. (b) The EDS spectra collected on the fibril are shown in a). (c) A BF TEM image showing a fibril with an inner-channel (red arrow) partially surrounded by biological material retrieved in the sample 72. (d) The EDS spectra collected on the fibril are shown in (e).
Discussion
In the present observational study we analysed, for the first time, samples of raw and wrought material coming from an asbestos-cement industry located near the city of Bishkek, the capital of Kyrgyzstan. We also analyzed air samples, collected on different sites of Bishkek and Kant, and lung tissues taken from the general population during clinical autopsies. Owing to the limited sample size, the study is more appropriately considered exploratory rather than confirmatory.
The analysis of the six samples of raw and wrought materials, carried out using different techniques (stereomicroscopic observation, SEM-EDS, PXRD, TEM-EDS and SAED), revealed that 5 out of 6 samples contained chrysotile; only 1 of them (sample C) did not contain it. Moreover, in only one among the six samples, a fibre with a straight shape and a SAED compatible with an amphibole structure was observed. The presence of unidentified material and the relatively small dimension of the fibre did not allow to clearly identify the fibre as an amphibole asbestos or other mineral species.
The air sampling of Bishkek and Kant cities revealed low concentration of airborne asbestos in Bishkek (from < LOD to 0.9 ff/L), whereas, in Kant, high concentrations of airborne asbestos (30.2 ff/L of chrysotile) were revealed 500 m far from plant 2; 1 km far from the same plant the airborne asbestos was lower but still present (9.6 ff/L). The asbestos concentration in air samples 1 km away from Plant 1 was, instead, only slightly higher than that observed in Bishkek city (maximum concentration of 1.2 ff/l). Notably, the heaviest concentrations of asbestos have been observed in samples taken from the most densely populated area of Kant. The town of Kant is located very close to plant 2 (Fig. 2), with some houses as close as 100 m from the plant. An airborne asbestos concentration as high as 30 ff/L has been detected north-east to the plant, whereas, according to the wind rose of Kant, the main wind direction is East and South West, suggesting an even higher airborne asbestos concentration in the areas aligned with the wind directions. In Bishkek, due to the absence of a clear source of asbestos pollution, the 4 sampling points were distributed roughly along the 4 cardinal points. In Kant, instead, considering the two factories close to the city, 3 sampling points were set in the urban fabric, at increasing distances and ideally along a transect. Our data about bulk samples and air samples are generally in line with the results of a study carried out in 2024 in the same cities59.
In order to interpret these results, it is useful to compare the data with those available in the literature about the situation in other countries before the asbestos ban. For example, in Italy, asbestos was banned in 1992 with Law 257/199260 and, before that, mixtures of chrysotile, crocidolite and amosite were extensively used in buildings. Asbestos concentrations we measured in Bishkek in 2023 are similar to those observed in Milan in 199161, taking into account that we considered only regulated fibres (longer than 5 μm). In 1991, the asbestos air contamination in Milan was mainly characterized by chrysotile with the prevalence of short and thin fibres, whose mean air concentration was 12.1 ± 4.6 ff/L61. These background levels were approximately constant across the seasons of the year and were not influenced by vehicular traffic rates and land use. The study was conducted one year before the Italian asbestos ban when ACM were still widely installed in Italy and asbestos plates covered an enormously large surface, similar to what currently happens in Kyrgyzstan. On the other hand, airborne asbestos concentrations observed in Kant were higher (more than double) than those observed in Casale Monferrato, where an important asbestos-cement factory was located and operated until 1986. In Casale Monferrato, in 1991, concentrations as high as 16.1 ff/L were observed61. Unfortunately, data about airborne asbestos concentrations in the areas nearby the most important asbestos-cement factories in Italy during the activity of such factories are not available in the literature. We know that in the 80 s the airborne concentration of asbestos in Milan (where no ACM factories were operating) was estimated between 0.6 and 3 ff/L62. According to a more recent study63the asbestos concentrations in 500 air samples collected indoors, from 111 Italian buildings holding ACM, were below 2 ff/L. Based on the data presented here, we can state that the actual situation in the capital of Kyrgyzstan, even though partly similar to Italy before the ban, presents some differences. In particular, the airborne asbestos in Bishkek city, despite the wide presence of chrysotile and the relatively close asbestos-cement plants (22 km far from the city), is low, whereas in the dwellings of Kant the detected concentrations of chrysotile are quite high (around 30 ff/L). This finding is in agreement with the extremely high exposure of workers employed in Kant industries64meaning that the safety measures are likely insufficient to reduce the dust levels inside the plant (and, therefore, in the adjacent areas). An important difference between Italy before the asbestos ban and Kyrgyzstan is that in Bishkek and Kant airborne chrysotile has been detected, while in Italy a mixture of airborne chrysotile and amphiboles asbestos was detected (consistently with what is known about the industrial use of asbestos, that exploited both chrysotile and amphiboles asbestos)61. As in air sample analysis we considered only regulated fibres, i.e. longer than 5 μm, according to the Italian Law9,10 (corresponding to the biologically more important fibres according to the WHO guidelines8) it is possible that airborne short chrysotile fibres were not detected. However, amphibole asbestos usually has a width no smaller than the SEM-EDS detection limit, suggesting that it is unlikely that these kinds of asbestos could have been missed in this study. Moreover, in a SEM-EDS study by our group about occupational exposure in Kant, only chrysotile has been detected during the monitoring of workers64. To our knowledge, other studies about airborne asbestos dispersion in CA were never performed. Yet, a similar study was carried out in 2018 in Iran, to track the concentration of asbestos fibres in Mashhad65. However, a specially conducted study by three laboratories with independent analysis of air samples from Tehran showed that existing Iranian publications on this topic contain not entirely correct data66. Namely, his study demonstrated that the Iranian studies of air pollution by fibrous particles significantly overestimated the results for asbestos. One of the primary causes of asbestos fibre emissions into the urban air has been identified in heavy traffic, which results in cars braking and clutching. As a result, asbestos was released by asbestos-containing car components. The summer and winter mean concentrations of asbestos detected in Mashhad were, respectively, 11.40 ± 2.14 and 14.38 ± 2.52 ff/L. Such concentrations were higher compared to those observed in Bishkek.
Nevertheless, other studies suggest that the likelihood of significant air pollution from asbestos fibers due to the use of vehicles with asbestos-containing friction products is minimal, if it exists at all. These products are only considered a potential source of asbestos fiber pollution when subjected to intensive mechanical processing (e.g., destruction)67. A study conducted in South Korea in 202168 examined 42 locations and various exposure sources. The results revealed, instead, much lower concentrations of asbestos in urban areas, namely 4.6 × 10 − 7 ff/L (measured by SEM), consistently with the asbestos ban introduced in Korea in 2009.
In the third part of this study, 28 lung samples taken from the general population during clinical autopsies have been examined with SEM-EDS. SEM-EDS investigations detected the presence of amphibole asbestos in only 3 out of 28 lung samples. In none of the 28 subjects chrysotile was detected at SEM-EDS analysis: this was unexpected, as chrysotile-cement is currently largely diffused in buildings and therefore the general population is very likely to be exposed to chrysotile. On the other hand, 4 out of the 28 samples have been examined with TEM-EDS. Three out of these 4 samples showed fibrils which were possibly identifiable as chrysotile. It must be specified that TEM-EDS allows the analysis of a very low quantity of lung tissue (less than 0.1 g), therefore it cannot be used to quantify the particles or to exclude the presence of specific particles (in this case asbestos). Furthermore, the particles observed at the TEM-EDS were degraded due to the permanence in the lung microenvironment and this hindered a conclusive analysis. However, the finding of fibres likely identifiable as chrysotile in 3 out of 4 samples is apparently in contrast with SEM-EDS results. This discrepancy between SEM and TEM results can be a consequence of the lower resolution of SEM-EDS, which can fail to identify very thin and partially degraded chrysotile fibres. It means that SEM-EDS is a technique apt to detect chrysotile bundles (as proved by previous studies conducted on lung samples revealing chrysotile69,70), but the performance of this tool is not sufficient when chrysotile fibres are particularly thin or very degraded, like in this study, where they could be detected only using TEM-EDS. The apparent absence of chrysotile in lung tissue observed by SEM-EDS and the detection of chrysotile in some of the same samples observed at the TEM-EDS suggest that the asbestos air pollution in areas not close to the asbestos industries could be mainly due to thin chrysotile fibrils. This is in line with the “two-phases model” of atmospheric asbestos pollution suggested by Chiappino et al.61. Initially, materials release bundles of fibres that, due to their weight, can reach only surrounding areas. At the same time, they release short and thin fibres in variable amounts according to the physical agent that causes the dispersion (wind, mechanical causes). Secondly, such bundles are fragmented by physical agents and ultrashort and ultrathin fibrils are released. They can be transported by air and be inhaled very far from the original source of dispersion. Considering that the asbestos-cement plants are located in Kant, this theory can explain the finding of a higher amount of fibres longer than 5 μm in Kant (close to the source of pollution) compared to Bishkek city and, at the same time, the scarcity of such fibres in the general population’s lungs. Besides, our findings are compatible with the hypothesis that airborne asbestos in Bishkek does not originate only from Kant industries’ emissions but also from the ACM diffused all around the urban environment.
The most likely reason why we did not find chrysotile using SEM-EDS is that most chrysotile fibres are already very thin before being inhaled by the population. However, the presence of chrysotile was expected, given the wide use of this mineral and its presence all over the city, as confirmed by air sampling. On the other hand, the presence of amphibole asbestos, such as amosite and tremolite/actinolite asbestos, in lung tissue taken from the general population (revealed using SEM-EDS) even though in only a small number of samples (10.7%) and in very low amounts, is remarkable. In fact, these data reveal that the Kyrgyz population is exposed not only to chrysotile, as already known, but also to amphibole asbestos. This was never reported before. The use of asbestos in CA is allowed assuming that only chrysotile is imported and used for production and that the risk for health of this mineral is lower compared to amphiboles. However, amphibole asbestos could be found in chrysotile ores (as indicated by a few studies, e.g25,71)., but in CA this fact is not regarded as an obstacle to its extraction and use. On one hand, the lower hazard for human health of chrysotile compared to that of amphiboles is still debated, and pure chrysotile has been demonstrated to increase the risk of developing neoplastic diseases such as lung cancer and mesothelioma19,20. On the other hand, the presence of amphibole asbestos in the general population’s lungs poses an even more serious public health issue related to the use of asbestos in CA, considering the undoubtedly high carcinogenetic potential of amosite and tremolite/actinolite asbestos (the kind of asbestos found in Bishkek dwellers’ lungs in the present study). We found a possible amphibolic fibre also in a sample of raw material. These two findings (tremolite/actinolite asbestos in lungs of the general population environmentally exposed to chrysotile and possible amphibole asbestos in raw chrysotile used for production in Kant) might be compatible with amphibolic contamination of the chrysotile extracted in Kazakhstan and imported in Kyrgyzstan. However, these data are not sufficient to draw conclusions on the possible origin of tremolite/actinolite asbestos. The widespread occurrence of tremolite/actinolite asbestos as an impurity in various rocks (not only in talc rocks) in some territories of former USSR wider even than in Italy has been reported by previous studies72,73. Yet, a small quantity of amosite (a single fibre, corresponding to 4288 ff/gdw) was found in the lungs of a subject from Bishkek and an asbestos body with an amosite core was found in another person from Kant.
On the base of the scientific literature, there are no evidence of presence of amosite deposits and amosite containing rocks in Kyrgyzstan74,75. A known deposit of amosite is located in central Russia76,77,78. Therefore, the occurrence of amosite cannot originate from natural sources within Kyrgyzstan. Based on current knowledge, the presence of amosite can only be attributed to anthropogenic sources, specifically to materials containing amosite, most likely asbestos-containing products which may have been imported from countries outside the former USSR26. Conversely, both talc-bearing rocks and rocks containing tremolite and actinolite are present in Kyrgyzstan. Thus, the occurrence of tremolite asbestos may originate from natural sources (rocks) within the country, although it cannot be excluded that it may also result from the use of naturally contaminated talc.
In conclusion, we found a remarkable amount of chrysotile in the air and also chrysotile in the lungs of the general population of the study area. Another important result is that not only chrysotile, but also amphibole asbestos, are present in the lungs of the general population. Such findings underline that, even in countries where the use of asbestos is allowed based on the presumed pureness of chrysotile used and the lower carcinogenic potential of chrysotile compared to amphibole asbestos, the general population could be exposed also to amphibole asbestos. Further studies are necessary to better characterize the exposure of the general population in CA. However, the serious issue represented by asbestos in such countries is clear. As already pointed out by our group47in CA asbestos-related diseases are underdiagnosed for various reasons, mainly related to outdated diagnostic tools. Due to economic and political reasons, it is very difficult to think about a possible universal ban on asbestos mining and use in a short time, but at least a strict regulation of its use is urgently needed in CA countries, where unacceptable levels of exposure not only for asbestos workers, as previously reported64but also for the general population, have been pointed out.
Data availability
The raw data are not openly available due to privacy issues (the companies from which the raw materials were collected do not want to be mentioned; the lung tissue data come from human subjects). All the dataset generated in this study are available on request to the corresponding author.
References
Bernstein, D. et al. Health risk of Chrysotile revisited. Crit. Rev. Toxicol. 43, 154–183 (2013).
Occupational Exposure to Asbestos. https://www.osha.gov/laws-regs/federalregister/1994-08-10
Campbell, W. J., Blake, R., Brown, L., Cather, E. & Sjoberg, J. Selected Silicate Minerals and Their Asbestiform Varieties, Mineralogical Definitions and Identification-Characterization. https://ntrl.ntis.gov/NTRL/dashboard/searchResults/titleDetail/PB271914.xhtml
Case, B. W., Abraham, J. L., Meeker, G., Pooley, F. D. & Pinkerton, K. E. Applying definitions of ‘asbestos’ to environmental and ‘low-dose’ exposure levels and health effects, particularly malignant mesothelioma. J. Toxicol. Environ. Health B Crit. Rev. 14, 3–39 (2011).
Vigliaturo, R. et al. Localization and dimensional range of amphibole particles retrieved from human alveolar epithelial cells. Minerals (Basel). 14, 101 (2024).
Vigliaturo, R. et al. Nanoscale transformations of amphiboles within human alveolar epithelial cells. Sci. Rep. 12, 1782 (2022).
Bernstein, D. M. The health risk of Chrysotile asbestos. Curr. Opin. Pulm Med. 20, 366–370 (2014).
World Health Organization. Regional Office for Europe. Air Quality Guidelines for Europe (WHO Regional Office for Europe, 2000).
Italian Legislative Decree 277/1991.
Italian, M. Decree 06/09/1994 (Annex 2B).
Gualtieri, A. F., Lusvardi, G., Zoboli, A., Di Giuseppe, D. & Lassinantti Gualtieri, M. Biodurability and release of metals during the dissolution of chrysotile, crocidolite and fibrous erionite. Environ. Res. 171, 550–557 (2019).
Gualtieri, A. F., Pollastri, S., Bursi Gandolfi, N. & Gualtieri, M. L. In vitro acellular dissolution of mineral fibres: A comparative study. Sci. Rep. 8, 7071 (2018).
Gualtieri, A. F. et al. New insights into the toxicity of mineral fibres: A combined in situ synchrotron µ-XRD and HR-TEM study of chrysotile, crocidolite, and erionite fibres found in the tissues of Sprague-Dawley rats. Toxicol. Lett. 274, 20–30 (2017).
Di Giuseppe, D. et al. Mineral fibres and asbestos bodies in human lung tissue: A case study. Minerals (Basel). 9, 618 (2019).
Churg, A. Deposition and clearance of Chrysotile asbestos. Ann. Occup. Hyg. 38, 625–633 (1994).
Hodgson, J. T. & Darnton, A. The quantitative risks of mesothelioma and lung cancer in relation to asbestos exposure. Ann. Occup. Hyg. 44, 565–601 (2000).
Berman, D. W. & Crump, K. S. A meta-analysis of asbestos-related cancer risk that addresses fiber size and mineral type. Crit. Rev. Toxicol. 38 (Suppl 1), 49–73 (2008).
Ferrante, D. et al. Mortality and mesothelioma incidence among Chrysotile asbestos miners in balangero, italy: A cohort study. Am. J. Ind. Med. 63, 135–145 (2020).
Mirabelli, D. et al. Excess of mesotheliomas after exposure to Chrysotile in balangero, Italy. Occup. Environ. Med. 65, 815–819 (2008).
Lin, S. et al. Cause-specific mortality in relation to chrysotile-asbestos exposure in a Chinese cohort. J. Thorac. Oncol. 7, 1109–1114 (2012).
Schüz, J. et al. Cancer mortality in Chrysotile miners and millers, Russian federation: main results (Asbest Chrysotile Cohort-Study). J. Natl. Cancer Inst. 116, 866–875 (2024).
Talc and Pyrophyllite Statistics and Information. https://www.usgs.gov/centers/nmic/talc-and-pyrophyllite-statistics-and-information
Friedrichs, K. H. & Molik, B. Microscopic observations on some fibrous dust samples. Zentralbl Bakteriol Mikrobiol Hyg. B. 181, 216–225 (1985).
Fitzgerald, S. M. Resolving asbestos and ultrafine particulate definitions with carcinogenicity. Lung Cancer. 189, 107478 (2024).
Cavallo, A. Environmental asbestos contamination in an abandoned Chrysotile mining site: the example of Val Malenco (central alps, Northern Italy). Episodes 43, 851–858 (2020).
Tossavainen, A., Kotilainen, M., Takahashi, K., Pan, G. & Vanhala, E. Amphibole fibres in Chinese Chrysotile asbestos. Ann. Occup. Hyg. 45, 145–152 (2001).
Chatfield, E. J. Associated minerals in Chrysotile deposits and their potential health risks. Front. Public. Health. 13, 1583469 (2025).
Stayner, L. T., Dankovic, D. A. & Lemen, R. A. Occupational exposure to Chrysotile asbestos and cancer risk: a review of the amphibole hypothesis. Am. J. Public. Health. 86, 179–186 (1996).
Cullen, M. R. The amphibole hypothesis of asbestos-related cancer–gone but not forgotten. Am. J. Public. Health. 86, 158–159 (1996).
Finkelstein, M. M. et al. Letter to the Editor re Bernstein : Health risk of chrysotile revisited. Crit Rev Toxicol, ; 43(2): 154–183. Crit. Rev. Toxicol. 43, 707–708 (2013). (2013).
Current Intelligence Bulletin 62. Asbestos Fibers and Other Elongate Mineral Particles: State of the Science and Roadmap for Research. (2011). https://doi.org/10.26616/NIOSHPUB2011159 doi:10.26616/nioshpub2011159.
IARC & Asbestos IARC Monographs on the Evaluation of Carcinogenic Risks To Humans (World Health Organization, 1977).
Smith, A. H. & Wright, C. C. Chrysotile asbestos is the main cause of pleural mesothelioma. Am. J. Ind. Med. 30, 252–266 (1996).
Rogers, A. J. et al. Relationship between lung asbestos fiber type and concentration and relative risk of mesothelioma. A case-control study. Cancer 67, 1912–1920 (1991).
WHO Global Plan of Action on Workers’ Health (. 2008–2017): baseline for implementation: global country survey 2008/2009: executive summary and survey findings. (2013). https://www.who.int/publications/i/item/WHO-FWC-PHE-2013-01
Current Asbestos Bans. (2024). http://ibasecretariat.org/alpha_ban_list.php
Furuya, S., Chimed-Ochir, O., Takahashi, K., David, A. & Takala, J. Global asbestos disaster. Int. J. Environ. Res. Public. Health 15, 1000 (2018).
WHO/ILO Joint Estimates of the Work-Related Burden of Disease and Injury, 2000–2016: Global Monitoring Report. (2021).
Coggon, D. Estimating population burdens of occupational disease. Scand. J. Work Environ. Health. 48, 83–85 (2022).
Kromhout, H., Cherrie, J. W. & van Tongeren, M. Letter to the editor. Environ. Int. 179, 108107 (2023).
Kromhout, H., Cherrie, J. W. & van Tongeren, M. Reply to letter to the editor by Driscoll et al. Ann. Work Expo Health. 69, 344–345 (2025).
Schlünssen, V. et al. The prevalences and levels of occupational exposure to dusts and/or fibres (silica, asbestos and coal): A systematic review and meta-analysis from the WHO/ILO joint estimates of the Work-related burden of disease and injury. Environ. Int. 178, 107980 (2023).
Boffetta, P. Health effects of asbestos exposure in humans: a quantitative assessment. Med. Lav. 89, 471–480 (1998).
Allen, L. P., Baez, J., Stern, M. E. C. & George, F. Asbestos: Economic Assessment of Bans and Declining Production and Consumption. (2017).
Baur, X. & Frank, A. L. Ongoing downplaying of the carcinogenicity of Chrysotile asbestos by vested interests. J. Occup. Med. Toxicol. 16, 6 (2021).
Frank, A. L. Global use of asbestos - legitimate and illegitimate issues. J. Occup. Med. Toxicol. 15, 16 (2020).
Kurzhunbaeva, Z. et al. Human exposure to asbestos in central Asian countries and health effects: A narrative review. Med. Lav. 115, e2024042 (2024).
Tossavainen, A., Kovalevsky, E., Vanhala, E. & Tuomi, T. Pulmonary mineral fibers after occupational and environmental exposure to asbestos in the Russian Chrysotile industry. Am. J. Ind. Med. 37, 327–333 (2000).
Tossavainen, A. et al. Health and exposure surveillance of Siberian asbestos miners: A joint Finnish-American-Russian project. Am. J. Ind. Med. Suppl. 1, 142–144 (1999).
International Trade Centre (ITC). Trade statistics for international business development. https://www.trademap.org/Index.aspx
ISO-International Organization for Standardization. ISO 13794:2019(en), Ambient Air — Determination of Asbestos Fibres — Indirect-Transfer Transmission Electron Microscopy Method. (2019). https://www.iso.org/obp/ui/en/#iso:std:iso:13794:ed-2:v1:en
ISO 14966. (2019). https://cdn.standards.iteh.ai/samples/75583/9fe57a430126426ca4f2478a5cc42da5/ISO-14966-2019.pdf
Gazzetta Ufficiale. https://www.gazzettaufficiale.it/eli/id/1994/09/20/094A5917/sg
Belluso, E. et al. Assessment of inorganic fibre burden in biological samples by scanning Electron Microscopy – Energy dispersive spectroscopy. Microchim Acta. 155, 95–100 (2006).
Vigliaturo, R., Capella, S., Rinaudo, C. & Belluso, E. Rinse and trickle’: a protocol for TEM Preparation and investigation of inorganic fibers from biological material. Inhal Toxicol. 28, 357–363 (2016).
Arletti, R. et al. High-temperature behavior of natural ferrierite: In-situ synchrotron X-ray powder diffraction study. Am. Mineral. 103, 1741–1748 (2018).
Giacobbe, C. et al. Depicting the crystal structure of fibrous ferrierite from British Columbia using a combined synchrotron techniques approach. J. Appl. Crystallogr. 52, 1397–1408 (2019).
Vigliaturo, R., Choi, J. K., Pérez-Rodríguez, I. & Gieré, R. Dimensional distribution control of elongate mineral particles for their use in biological assays. MethodsX 7, 100937 (2020).
Ковалевский, Е. В., Шаршенова, А. А., Отаров, Е. Ж., Касымбеков, Ж. О. & Цхомария, И. М. Оценка Потенциальных Рисков Загрязнения Воздуха волокнами асбеста: evaluation of potential risks of air pollution by asbestos fibres. Sci. Practical J. Healthc. Kyrgyzstan. 116–125. https://doi.org/10.51350/zdravkg2024.4.12.15.116.125 (2025).
LEGGE 27. Marzo, N. 257 Norme relative alla cessazione dell’impiego dell’amianto (1992).
Chiappino, G., Sebastien, P. & Todaro, A. [Atmospheric asbestos pollution in the urban environment: milan, Casale monferrato, brescia, ancona, Bologna and florence]. Med. Lav. 82, 424–438 (1991).
Bollettino Ufficiale Regione Lombardia -Testo Coordinato Delle Circolari Del Settore. Sanità E Igiene Del 24/07/1985 N (1986). 41 E 4/9/1975 N. 65.
Bruno, M. R. et al. Airborne asbestos fiber concentration in buildings: surveys carried out in Latium (central Italy). Minerals (Basel). 13, 233 (2023).
Kurzhunbaeva, Z. et al. Occupational exposure to Chrysotile in an asbestos cement factory in Kyrgyzstan. Ann. Work Expo Health. https://doi.org/10.1093/annweh/wxae059 (2024).
Moteallemi, A. et al. Monitoring of airborne asbestos fibers in an urban ambient air of Mashhad city, iran: levels, Spatial distribution and seasonal variations. J. Environ. Health Sci. Eng. 18, 1239–1246 (2020).
Khadem, M., Somea, M. S., Hassankhani, H. & Heravizadeh, O. R. Joint Iranian-Russian studies of airborne asbestos concentrations in tehran, iran, in 2017. Atmos. Environ. (1994). 186, 9–17 (2018).
Chrysotile Asbestos: Full Public Report. (1999).
Jung, H. S. et al. Changes in concentrations and characteristics of asbestos fibers dispersed from corrugated asbestos cement sheets due to stabilizer treatment. J. Environ. Manage. 285, 112110 (2021).
Capella, S., Bellis, D., Fioretti, E., Marinelli, R. & Belluso, E. Respirable inorganic fibers dispersed in air and settled in human lung samples: assessment of their nature, source, and concentration in a NW Italy large City. Environ. Pollut. 263, 114384 (2020).
Visonà, S. D. et al. A postmortem case control study of asbestos burden in lungs of malignant mesothelioma cases. J. Transl Med. 21, 875 (2023).
McDonald, J. C. et al. Mesothelioma and asbestos fiber type. Evidence from lung tissue analyses. Cancer 63, 1544–1547 (1989).
Petriglieri, J. R. et al. Naturally occurring asbestos in Southern italy: geological and mineralogical investigation of fibrous Antigorite from Calabrian serpentinites in view of its hazard assessment. Sci. Total Environ. 970, 178970 (2025).
Bloise, A. et al. Evaluation of asbestos dispersion during laser ablation of rocks containing naturally occurring asbestos (NOA). Heliyon 10, e39624 (2024).
Orozbaev, R. T., Takasu, A., Bakirov, A. B., Tagiri, M. & Sakiev, K. S. Metamorphic history of eclogites and country rock gneisses in the Aktyuz area, Northern Tien-Shan, kyrgyzstan: a record from initiation of subduction through to oceanic closure by continent–continent collision. J. Metamorph Geol. 28, 317–339 (2010).
Atlas of Mineral Resources of the ESCAP Region. Vol. 13, Geology and Mineral Resources of Kyrgyzstan. (UN. ESCAP, New York, (1998).
Ilyin, A. V. Neoproterozoic banded iron formations. Lithol. Min. Resour. 44, 78–86 (2009).
Kovalev, K. P. et al. The Gorevskoe Pb–Zn deposit (Siberia, Russia): Mineral Composition and Features of Ore Mineralization. Geol. Ore Deposits. 65, 283–314 (2023).
Amosite. https://www.mindat.org/min-8738.html
Acknowledgements
The authors would like to thank Dr. Davide Campagnolo, Dr. Giacomo Fanti and Dr. Sabrina Rovelli for their contribution in the preparation of the airborne fibres sampling and analysis campaign.
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Z. Kurzhunbaeva, N. Tulepbergenov, E. Mindiyarova, O. Kasymov, K. Dzhusupov: investigation; data curation; resources; A. Spinazzè, D.M. Cavallo: investigation; formal analysis; validation; writing- review and editing. G. Cecchetto: writing- review and editing; visualization. C. Colosio: supervision; writing- review and editing. R. Vigliaturo, G.P. Servetto: investigation; formal analysis; validation; writing- review and editing. S. Capella, E. Belluso, B. Bertoglio: investigation; formal analysis; validation; writing- review and editing. S.D. Visonà: writing- original draft; project administration.
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Kurzhunbaeva, Z., Vigliaturo, R., Servetto, G. et al. Assessment of asbestos exposure in Kyrgyzstan through analysis of raw and processed materials, air samples and human lung tissue. Sci Rep 15, 25114 (2025). https://doi.org/10.1038/s41598-025-10736-1
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DOI: https://doi.org/10.1038/s41598-025-10736-1
