Lung fibre burden and risk of malignant mesothelioma in shipyard workers: a necropsy-based case-control study.

OBJECTIVES: In Italy, the highest pleural cancer mortality and incidence have been observed among Italian regions where the 2 largest Italian shipyards were (and are) located. The objective of this study was to assess the exposure-response relationship for mesothelioma among male workers employed in the Monfalcone, Italy, shipyard. METHODS: We conducted a necropsy-based case-control study. Cases (N = 102) were mesothelioma decedents and controls were those with lung cancer (N = 84). Complete job histories were available; the lung fibre content was measured using a scanning electron microscope with X-ray fluorescence, after sample preparation according to the European Respiratory Society guidelines. Odds ratios and 95% confidence intervals of mesothelioma by fibre type and lung fibre burden, as a categorical or continuous variable, were assessed by unconditional logistic regression, adjusted for age and time since exposure cessation. Analyses for the amphibole and chrysotile lung fibre burden were mutually adjusted. We calculated a cumulative exposure index by applying a job-exposure matrix to the job histories of study cases and assessed its correlation with the lung fibre burden. RESULTS: We found an odds ratio of 22.0 (confidence intervals 5.66-85.7) for the highest lung fibre burden category (mean 43.8 million total asbestos fibres per gram of dry tissue) compared with the reference (mean 0.48). Using log10-transformed lung fibre burden, we found that the odds ratio was 3.71 (confidence intervals 2.03-6.79) for a 10-fold lung fibre burden increase. Results for the amphibole lung fibre burden were similar. Odds ratios increased over chrysotile lung fibre burden categories (P-trend = 0.025), and the odds ratio for a 10-fold increase was 4.73 (confidence intervals 0.32-70.4). CONCLUSIONS: The cumulative exposure index was correlated with total and amphibole lung fibre burden, but not with chrysotile lung fibre burden. Mesothelioma risk was proportional to total, amphibole, and chrysotile lung fibre burden in shipyard workers.

Lung asbestos fiber burden analysis: effects of the counting rules for legal medicine evaluations.

OBJECTIVES: The work shows the effect of counting rules, such as analysis magnification and asbestos fiber dimension to be count (with length ≥5 µm or also asbestos fibers with length <5 µm) in the lung asbestos fiber burden analysis for legal medicine evaluations. METHODS: On the same lung tissue samples, two different analyses were carried out to count any asbestos fibers with length ≥1 µm and with length ≥5 µm. Results of the amphibole burden of the two analyses were compared by linear regression analysis on log10-transformed values. RESULTS: The analysis should be carried out at an appropriate magnification and on samples prepared in such a way as they allow the counting of very fine fibers. If the analysis is limited to the asbestos fibers with length ≥5 µm, there is a high risk of not detecting possible residual chrysotile fiber burden and thinner crocidolite asbestos fibers. CONCLUSIONS: On average we estimated that 1 amphibole fiber with length ≥5 µm corresponds to ∼8 amphibole fibers with length ≥1 µm in the lung. The values of the Helsinki criteria should be updated taking this into account.

Asbestos Lung Burden Does Not Predict Survival in Malignant Pleural Mesothelioma: A Necropsy-Based Study of 185 Cases.

INTRODUCTION: Malignant pleural mesothelioma is an asbestos-related disease with poor survival. The prognostic role of histologic subtype is well established. Some studies (without a biological hypothesis) suggested that higher asbestos lung burden is associated with reduced survival. METHODS: We selected subjects from two series of necropsies: residents in Brescia province (North-West Italy) and workers (or persons living with them) employed in the Monfalcone shipyards (North-East Italy). Asbestos fibers and asbestos bodies in lung samples were counted using a scanning electron and an optical microscope, respectively. Separately in the two series, we analyzed median survival time and fitted multivariable Cox regression models (adjusted for sex, period and age at diagnosis, and histopatholocical diagnosis) to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for three levels of asbestos fiber counts (reference: <1 million fibers/g of dry lung tissue). RESULTS: We analyzed 185 necropsies, 83 in Brescia and 102 in Monfalcone. Despite a much higher lung burden in Monfalcone patients, median survival was slightly shorter in Brescia (8.3 mo) than in Monfalcone (10.2 mo). In Brescia, medium (1.0-9.9) and high (10+) fiber burden HRs were 0.91 (95% CI: 0.54-1.53) and 1.23 (95% CI: 0.41-3.70), respectively. In Monfalcone, the corresponding HRs were 1.18 (95% CI: 0.59-2.35) and 1.63 (95% CI: 0.77-3.45), respectively. CONCLUSIONS: No relationship between asbestos lung burden and survival was found. Histologic subtype was the strongest prognostic determinant.

Is Mesothelioma Unrelated to the Lung Asbestos Burden? Comment on Visonà et al. Inorganic Fiber Lung Burden in Subjects with Occupational and/or Anthropogenic Environmental Asbestos Exposure in Broni (Pavia, Northern Italy): An SEM-EDS Study on Autoptic Samples. Int. J. Environ. Res. Public Health 2021, 18, 2053.

We read with interest the report by Visonà and coworkers on the lung asbestos fiber burden in an autopsy series of decedents from mesothelioma (MM: 59 cases) and individuals who "suffered from asbestosis and died of its complications" (13 cases) [...].

[Asbestos exposure and related diseases among friction products workers (1971-2016)]. / Esposizione ad amianto e patologie correlate in addetti alla produzione di materiali di attrito (1971-2016).

SUMMARY: Worldwide studies have been published on the mortality of workers employed in asbestos-based materials for the production of clutches and brakes. However no one of these studies is related to Italian cases. Furthermore, not even surveys have been conducted in Italy to characterize the correlation between asbestos exposures and the possible occurring of asbestos-related disease. Our objectives are the following: i) to assess and quantify the asbestos exposure cases, ii) to describe the nature and the frequency of asbestos-related diseases among blue collar employees of an important factory producing brakes and clutches with chrysotile asbestos content from 1971 to 1993 and iii) to provide preliminary data on cumulative asbestos exposure estimated using lung fibre burden analysis. Critical appraisal of airborne asbestos fibre measurements and identification of cases of asbestos-related diseases between the blue collar employees, either notified to the local health authority or recovered from the Italian national Mesothelioma registry was investigated. Lung fibre burden analysis using the lung tissue samples from two deceased blue collar employees was also performed. Airborne asbestos fibre measurements (carried out in 1982) suggested asbestos fibres average concentrations of about 0.3 f/ml, while all 1992 measurements showed results below 0.1 f/ml. Furthermore, since 1988, we identified four cases of pleural plaques, three cases of asbestosis and seven cases of lung cancer. No case of malignant mesothelioma was found. In both lung cancer cases, analysed to measure the lung fibre burden, commercial amphiboles were absent or in limited concentration but chrysotile and, especially, tremolite asbestos were present in noticeable amount. In conclusion, since 1971 and up to early 1980s, exposure to chrysotile asbestos and talc, likely contaminated by tremolite, had been significant and comparable to levels causing asbestosis long-term risk. No case of malignant mesothelioma was found, that is consistent with the absence of amphiboles and with the lower risk of mesothelioma associated with the chrysotile asbestos. However a subset of the blue collar employees, the ones employed later on, could still have not reached the full risk condition, and so being still at risk of developing malignant mesothelioma. In the two lung cancer cases studied, the lung fibre burden was essentially made of chrysotile and tremolite. Lastly, lung cancer occurrence in the population of blue collar employees has been likely underestimated and the correct determination of lung cancer risk should be done through the mortality analysis of this population.

Severe silicosis due to diatomaceous earth in dental alginate: a necropsy study.

BACKGROUND: Severe silicosis from occupational exposure to calcined diatomaceous earth has been observed in the past, due to the high-temperature transformation of amorphous silica in crystalline phases, mainly cristobalite. In dental alginate production and use a silica exposure may be underestimated. OBJECTIVES: To describe the clinical picture, the scenario and pattern of occupational exposure to silica and the corresponding necroscopic findings of a case of silicosis in a worker engaged in the production of alginates for dental use. METHODS: A commercial sample of calcinated diatomaceous earth and necroscopic lung samples were analysed by scanning electron microscopy (SEM-EDS) and X-ray diffraction (XRD) for the quali-quantitative determination of crystalline silica. Material safety data sheets (MSDSs) of diatomaceous earth produced in 2002 and 2018 were examined to assess the information content on silicosis risk. Clinical findings and post-mortem examinations of the worker are evaluated. RESULTS: A cristobalite concentration of 36% (wt/wt) was determined in the diatomaceous earth sample and a large amount of diatom fragments were observed in lung samples. The DRX spectra indicated the presence of cristobalite either in the bulk sample or in the lung tissues. The MSDS dated 2002 reported the presence of SLC up to 63% with cristobalite concentrations minor of 60%, and the resulting risk of silicosis, while the MSDS dated 2018 and referred to a commercial product currently on the market indicated a concentration of cristobalite minor of 1% and no risk of silicosis. The worker was suffering from a severe silicosis, histologically confirmed by necropsy. CONCLUSION: The present case-study revealed that the risk of silicosis from calcined diatomaceous earths used to produce dental alginates has been ignored. The lack of engineering controls and personal protection measures led to a high cristobalite lung burden, consistent with the development of a severe silicosis that were a contributing factor of death. A MSDS of a commercial product currently on the market does not report this serious hazard.

Lung Asbestos Fibre Burden and Pleural Mesothelioma in Women with Non-occupational Exposure.

BACKGROUND: Malignant pleural mesothelioma (MPM) due to environmental and familial (domestic) asbestos exposure is well recognized. However, information on cumulative asbestos dose in subjects affected by MPM is limited. OBJECTIVES: To evaluate the residual lung asbestos fibre and asbestos body burden in women with MPM with past environmental and/or familial asbestos exposure. METHODS: We collected lung samples from autopsies regarding 15 non-occupationally asbestos-exposed MPM cases, divided in three groups: (i) familial exposure from the Fincantieri shipyards in Monfalcone (No. 7), (ii) environmental and familial asbestos exposure from the asbestos-cement plant Fibronit in Broni (No. 6), and (iii) environmental exposure from the Fibronit plant (No. 2). Asbestos body (AB) and fibres (AF) per gram of dry lung tissue were counted by optical and scanning electron microscopy, respectively, and expressed as geometric means and standard deviations (GM, GSD). RESULTS: GM/GSD of AB counts were 6123/9.6 (Group 1), 13 800/10.4 (Group 2), and 8400/1.1 (Group 3); GM/GSD of AF were 0.6/2.1 (Group 1), 7.9/2.1 (Group 2), and 6.0/2.3 (Group 3) million. Pleural plaques were observed in 12 cases. CONCLUSIONS: Exclusive familial exposure to asbestos determined cumulative doses close to those observed in moderate occupational exposure circumstances. Our results also suggest that combined environmental and familial exposures may cause unexpectedly high cumulative fibre doses.

Relationship between pleural plaques and biomarkers of cumulative asbestos dose. A necropsy study.

BACKGROUND: The relationship between pleural plaques and cumulative asbestos exposure is controversial. OBJECTIVES: To evaluate the relationship between lung asbestos bodies (AB) and fibres (AF) and plaques presence and extension. METHODS: In a necropsy series of shipyard workers with asbestos-related diseases, we measured counts (per g of dry lung tissue) of AB (thousands) and AF>1 µm (millions). Pleural plaques were classified into three extension grades. We fitted univariate and multivariable linear (dependent variables: AB and AF, log10 transformed) and multinomial (dependent variable: plaques grade) regression models. RESULTS: We analysed 124 subjects, 13 without plaques 20 with grade 1, 69 with grade 2, and 22 with grade 3 plaques. Geometric means (GM) of AB were 10.6, 23.3, 126, and 140 in the four groups respectively (P=0.0001). GMs for AF (mostly amphiboles) were 1.2, 1.4, 7.3, and 12.9 (P=0.0001). AB and AF were strongly correlated (r=0.81). The likelihood of no plaques and grade 1 plaques decreased with increasing AB and AF doses, with a corresponding increase of grade 2 and 3 plaques. Plaque presence and extension was also associated with histologically verified asbestosis (P<0.001). CONCLUSIONS: Our study showed a strong positive relationship between pleural plaque presence and extension and both lung asbestos burden and asbestosis.

Pleural mesothelioma in doll manufacture: possible asbestos exposure. / Mesoteliomi pleurici in addette alla fabbricazione di bambole: esposizione ad amianto?

BACKGROUND: The occurrence of malignant mesothelioma is almost always causally associated to asbestos exposure but, considering women occurrences, this association is often difficult to demonstrate and consequently the asbestos exposure is defined as 'unknown'. OBJECTIVES: To describe the working activity and to give occupational asbestos exposure probability estimation related to an uncommon and poorly investigated productive sector: doll manufacture. METHODS: From the Province of Brescia Mesothelioma Registry, established in 1993 on population-based criteria, we have extracted the certified mesothelioma diagnosis cases, related to patients who were employed for some time in doll manufacture. RESULTS: Among the 757 total cases of malignant mesothelioma registered and studied up to 2016, we found 3 cases of pleural epithelial mesothelioma histologically diagnosed in young women who had worked in two doll manufacturing companies and whose asbestos exposure had been initially defined as 'unknown', because an environmental, family or extra-professional asbestos exposure was considered unlikely. However, the judicial autopsy performed on one of the 3 women had allowed examining lung tissue samples with Scanning Electron Microscopy. This technique showed a concentration of amphiboles fibers of about 12,000,000 per gram of dry lung tissue, with a consequent re-classification of asbestos exposure from 'unknown' to 'occupational certified'. DISCUSSION: Mesotheliomas in women with no apparent occupational asbestos exposure are normally referred to life or family environmental exposure. Moreover, it is known that occupational asbestos exposure in women is difficult to recognize. Previously, only one publication had reported two cases of mesothelioma in cloth doll manufacture. The occurrence of two mesothelioma cases in the same company out of the three here presented was suggesting an occupational exposure. The finding of a high amphibole fibers lung concentration confirmed the previous hypothesis, despite the impossibility to determine the circumstances with good evidence. CONCLUSION: The three cases of mesothelioma in doll production workers suggest that also in this restricted manufacturing sector had occurred an occupational asbestos exposure, which is up to now unknown and isn't due only to the use of sewing or ironing machines. The lung asbestos fibers burden analysis is confirmed to be a decisive factor in the assessment of mesothelioma cases with 'unknown' exposure.

Pleural malignant mesothelioma in dental laboratory technicians: A case series.

Asbestos was used in dentistry as a binder in periodontal dressings and as lining material for casting rings and crucible. However, until now, only one case of malignant mesothelioma with occupational exposure to asbestos in dental practice has been reported. We present 4 pleural mesotheliomas out of 5344 cases identified in Lombardy, Italy, in 2000-2014. Three men had been working as dental laboratory technicians, with asbestos exposure for 10, 34, and 4 years, and one woman had been helping her husband for 30 years in manufacturing dental prostheses. The men described the use of asbestos as a lining material for casting rings, while the woman was not able to confirm this use. We confirm the association of malignant mesothelioma with dental technician work. Dental technicians suffering from mesothelioma should be questioned about past occupational asbestos exposure.

Residual fibre lung burden among patients with pleural mesothelioma who have been occupationally exposed to asbestos.

OBJECTIVES: To evaluate the lungs asbestos fibres concentration in participants with malignant pleural mesothelioma (MPM) who have been occupationally exposed. METHODS: The lung samples were obtained from pleuropneumonectomies or autopsies of 271 male MPMs. The lung samples were examined through scanning electron microscopy. Retrospective assessment was used to assess for asbestos exposure. This study includes 248 MPMs with an occupational exposure defined as either 'definite' or 'probable' or 'possible'. RESULTS: The participants had finished working in asbestos exposure conditions more than 20 years ago (on average 26.1±11.0 years). The fibre burden resulted with a geometric mean equal to 2.0 (95% CI 1.6 to 2.4) million fibres per gram of dry lung tissue. The burden was higher among participants employed in asbestos textiles industry and in shipyards with insulation material, if compared with construction workers or non-asbestos textile workers or participants working in chemicals or as auto mechanics. 91.3% of MPMs had a detectable amount of amphibole fibres. A strong lung clearance capability was evident among workers exposed to chrysotile fibres. Owing to that, the 1997 Helsinki Criteria for occupational exposure were reached in <35% of cases among participant working in construction, in metallurgical industry, in chemical or textile industry and among those performing brake repair activities. CONCLUSIONS: The MPM cases are now occurring in Italy in participants who ceased occupational asbestos exposure decades before the analysis. A large majority still shows a residual content of amphibole fibres, but given the lung clearance capability, attribution to occupational exposure cannot rely only on fibres detection.

[Pleural mesothelioma in a school teacher: asbestos exposure due to DAS paste]. / Mesotelioma pleurico in maestro elementare: esposizione ad amianto dovuta alla pasta DAS.

BACKGROUND: Malignant mesothelioma cases among primary school teachers are usually linked with asbestos exposure due to the mineral contained in the building structure. Among the approximately 12,000 cases of mesothelioma described in the fourth report of the National Mesothelioma Register, 11 cases of primary school teachers are reported, in spite of the fact that the "catalogue of asbestos use" does not describe circumstances of asbestos exposure other than or different to that due to asbestos contained in the buildings. Four cases in the Brescia Provincial Mesothelioma Register are identified as teachers, without this circumstance of exposure. OBJECTIVES: To characterize the asbestos concentration and fibre type retained in the lungs of a teacher reported as a new mesothelioma case and preliminarily classified as of unknown asbestos exposure. METHODS: The mesothelioma case presented here was diagnosed at age 78 and malignant mesothelioma was confirmed at autopsy; the patient was interviewed directly for occupational history. Samples of lung parenchyma from necropsies were collected, stored and analyzed by scanning electron microscope (SEM) and samples of DAS paste were analyzed by SEM to detect asbestos fibre content. RESULTS: It was possible to confirm past exposure to DAS paste in forming and finishing dry items and toys during school recreational activity almost every day from the mid-60s to about the mid-70s. Subsequent SEM analysis showed: i) chrysotile fibres were found in an old and unused pack of DAS paste; ii) a lung burden of 1,400 asbestos bodies, 310.000 total asbestos fibres (33% chrysotile, 67% amphibole) and 210.000 talc fibre per gr/dry lung tissue was detected from necropsies performed on the subject. These results seem to be in agreement with an occupational exposure to asbestos due to past use of DAS paste. After the investigation, this case was reclassified from "unknowun" to " sure" occupational asbestos exposure. The occupational origin of the tumour was recognized by the Italian Workers' Compensation Authority (INAIL). CONCLUSION: This case suggests i) the need to carry out any possible detailed studies of the circumstances and exposure sources whenever any mesothelioma case is classified as "asbestos exposure unknown", according to the guidelines of the National Mesothelioma Register, ii) handling of DAS paste can be considered as sure asbestos exposure and iii) it should be borne in mind that mesothelioma cases can occur even after cumulative low, occupational exposure, even only to chrysotile.

Asbestos Lung Burden in Necroscopic Samples from the General Population of Milan, Italy.

The present study analysed the asbestos lung burden in necroscopic samples from 55 subjects free from asbestos-related diseases, collected between 2009 and 2011 in Milan, Italy. Multiple lung samples were analysed by light microscopy (asbestos bodies, AB) and EDXA-scanning electron microscopy (asbestos fibres and other inorganic fibres). Asbestos fibres were detected in 35 (63.6%) subjects, with a higher frequency for amphiboles than for chrysotile. Commercial (CA) and non-commercial amphiboles (NCA) were found in roughly similar frequencies. The estimated median value was 0.11 million fibres per gram of dry lung tissue (mf g(-1)) for all asbestos, 0.09 mf g(-1) for amphiboles. In 44 (80.0%) subjects no chrysotile fibres were detected. A negative relationship between asbestos mass-weighted fibre count and year of birth (and a corresponding positive increase with age) was observed for amphiboles [-4.15%, 95% confidence interval (CI) = -5.89 to -2.37], talc (-2.12%, 95% CI = -3.94 to -0.28), and Ti-rich fibres (-3.10%, 95% CI = -5.54 to -0.60), but not for chrysotile (-2.84%, 95% CI = -7.69 to 2.27). Residential district, birthplace, and smoking habit did not affect the lung burden of asbestos or inorganic fibres. Females showed higher burden only for amphiboles (0.12 versus 0.03 mf g(-1) in males, P = 0.07) and talc fibres (0.14 versus 0 mf g(-1) in males, P = 0.03). Chrysotile fibres were shorter and thinner than amphibole fibres and NCA fibres were thicker than CA ones. The AB prevalence was 16.4% (nine subjects) with concentrations ranging from 10 to 110 AB g(-1) dry, well below the 1000 AB g(-1) threshold for establishing occupational exposure. No AB were found in subjects younger than 30 years. Our study demonstrated detectable levels of asbestos fibres in a sample taken from the general population. The significant increase with age confirmed that amphibole fibres are the most representative of cumulative exposure.

Outdoor radon and traffic load levels as cumulative indicators of PM10 and benzene air pollution.

UNLABELLED: A new simple cumulative index, named Critical Index (CI), linearly dependent on traffic load and outdoor 222Rn levels (as related to the air mixing condition) was introduced in order to determine the cumulative effect of traffic and atmospheric dilution on PM10 (particles with aerodynamic diameter < 10 microm) and Benzene concentrations in Milan (Italy) air in the years 2000 and 2001. Benzene, PM10 data were obtained from the public air quality monitoring stations. The traffic load was evaluated by the number of vehicles circulating in a street in the centre of Milan. Outdoor 222Rn measurements were carried out by the authors. Traffic data and mixing layer height (estimated through the outdoor 222Rn air activity) combined in a cumulative index, allowed to demonstrate the correlation of traffic load with high Benzene and PM10 pollution levels without exception. IMPLICATIONS: Through the introduction of a new simple cumulative index that is linearly dependent on traffic load and outdoor radon levels (as related to the air mixing condition), it was possible to ascertain the cumulative effect of traffic and atmospheric dilution on PM10 and benzene concentrations in Milan air in the years 2000 and 2001. The proposed methodology will be used to monitor the situation with data collected 10 yr later, in order to evaluate air quality improvement taking into account the influence of different meteorological conditions of the two periods compared.

Asbestos fibre burden in the lungs of patients with mesothelioma who lived near asbestos-cement factories.

BACKGROUND: Epidemics of malignant mesothelioma are occurring among inhabitants of Casale Monferrato and Bari never employed in the local asbestos-cement (AC) factories. The mesothelioma risk increased with proximity of residence to both plants. OBJECTIVES: To provide information on the intensity of environmental asbestos exposure, in the general population living around these factories, through the evaluation of the lung fibre burden in mesothelioma patients. METHODS: We analysed by a scanning electron microscope equipped with X-ray microanalysis wet (formalin-fixed) lung tissue samples from eight mesothelioma patients who lived in Casale Monferrato or Bari and underwent surgery. Their occupational and residential history was obtained during face-to-face interviews. Semi-quantitative and quantitative indices of cumulative environmental exposure to asbestos were computed, based on residential distance from the AC plants and duration of stay. RESULTS: The lung fibre burden ranged from 110 000 to 4 300 000 fibres per gram of dry lung (f/g) and was >1 000 000 f/g in three subjects. In four cases, only amphibole fibres were detected. Environmental exposures had ceased at least 10 years before samples were taken. No patient had other definite or probable asbestos exposures. A linear relationship was observed between the lung fibre burden and all three indices of environmental cumulative exposure to asbestos. CONCLUSIONS: Environmental exposure to a mixture of asbestos fibres may lead to a high lung fibre burden of amphiboles years after exposure cessation. The epidemiological evidence of an increased mesothelioma risk for the general population of Casale Monferrato and Bari, associated with asbestos contamination of the living environment, is corroborated.

Airborne concentrations of chrysotile asbestos in serpentine quarries and stone processing facilities in Valmalenco, Italy.

Asbestos may be naturally present in rocks and soils. In some cases, there is the possibility of releasing asbestos fibres into the atmosphere from the rock or soil, subsequently exposing workers and the general population, which can lead to an increased risk of developing asbestos-related diseases. In the present study, air contaminated with asbestos fibres released from serpentinites was investigated in occupational settings (quarries and processing factories) and in the environment close to working facilities and at urban sites. The only naturally occurrence of asbestos found in Valmalenco area was chrysotile; amphibole fibres were never detected. An experimental cut-off diameter of 0.25 µm was established for distinguishing between Valmalenco chrysotile and antigorite single fibres using selected area electron diffraction analyses. Air contamination from chrysotile fibres in the examined occupational settings was site-dependent as the degree of asbestos contamination of Valmalenco serpentinites is highly variable from place to place. Block cutting of massive serpentinites with multiple blades or discs and drilling at the quarry sites that had the highest levels of asbestos contamination generated the highest exposures to (i.e. over the occupational exposure limits) asbestos. Conversely, working activities on foliated serpentinites produced airborne chrysotile concentrations comparable with ambient levels. Environmental chrysotile concentrations were always below the Italian limit for life environments (0.002 f ml(-1)), except for one sample collected at a quarry property boundary. The present exposure assessment study should encourage the development of an effective and concordant policy for proper use of asbestos-bearing rocks and soils as well as for the protection of public health.

[Lung asbestos fibre burden in textile workers with malignant mesothelioma]. / Carico polmonare di fibre di amianto in mesoteliomi di lavoratori tessili.

BACKGROUND: Lung burden of amphibole fibres is a good biological index of occupational cumulative asbestos exposure. Malignant mesothelioma (MM) has been amply documented in textile industry workers, dealing either with mineral fibres or with vegetable and animal fibres. So far the concentration of asbestos fibres in lung tissue among textile workers has not been reported in Italy. We analysed asbestos burden in the lung tissue of eleven textile-workers with malignant mesothelioma, mainly employed in industries near Brescia, in the North of Italy. OBJECTIVES: To characterize lung asbestos concentration and fibre type retained in the lung of asbestos and non-asbestos textile workers. METHODS: Sample of lung parenchyma from necropsies and extrapleural pneumonectomy were collected, stored and analysed by scanning electron microscope, according to the methods recommended in the current scientific literature. Nine patients were interviewed directly for occupational history. RESULTS: Eleven cases of MM (10 primary pleural, 1 primary peritoneal) were collected, 9 women and 2 men, aged between 51 and 87 years, 4 asbestos-textile workers and 7 non-asbestos textile workers. The highest values of asbestos fibres were detected in all the workers of the former group and in 3 non-asbestos workers (jute recycling employees), with concentrations between 9.1 and 397 million/g of dried lung tissue. The total fibre concentration in the other 4 non-asbestos textile workers (silk and cotton production workers) ranged from 0.33 to 1.2 million/g of dried lung tissue. In only one of these subjects, did lung amphibole burden exceed 1,000,000 amphibole fibres longer than 1 microm per g of dried tissue. Eight cases out of eleven, showed a higher concentration of amphiboles than chrysotile. We detected amphibole fibres in all the "non-asbestos" textile workers and for two of them a higher concentration of tremolite. CONCLUSION: i) Among textile workers using asbestos or jute recycling, the asbestos fibre burden is as high as that found in other high risk jobs (e.g. asbestos-cement workers); ii) among non-asbestos textile workers, employed in cotton and silk production, the fibre content in lung tissue was much lower and it was nonetheless above the occupational cut-off for one of them; iii) tremolite found in lung tissue of non-asbestos textile workers with MM could be a contaminant of chrysotile friction materials or originate, with other amphiboles, from some other source as yet to be investigated.

[Mesothelioma in construction workers: risk estimate, lung content of asbestos fibres, claims for compensation for occupational disease in the Veneto Region mesothelioma register]. / Mesoteliomi negli edili: frequenza, stima del rischio, carico polmonare di fibre di amianto, domande e riconoscimenti per malattia professionale nel Registro regionale veneto dei casi di mesotelioma.

BACKGROUND: Work in the construction industry is causing the highest number of mesotheliomas among the residents of the Veneto Region (north-east Italy, 4,5 million inhabitants). OBJECTIVES: To sum up the results on occurrence, asbestos exposure, lung fibre content analyses, and compensation for occupational disease. METHODS: Case identification and asbestos exposure classification: active search of mesotheliomas that were diagnosed via histological or cytological examinations occurring between 1987 and 2006; a probability of asbestos exposure was attributed to each case, following interviews with the subjects or their relatives and collection of data on the jobs held over their lifetime. Risk estimate among construction workers: the ratio between cases and person-years, the latter derived from the number of construction workers reported by censuses. Lung content of asbestos fibres: examination of lung specimens by Scanning Electron Microscope to determine number and type of fibres. Claims for compensation and compensation awarded: data obtained from the National Institute for Insurance against Occupational Diseases available for the period 1999-2006. RESULTS: of 952 mesothelioma cases classified as due to asbestos exposure, 251 were assigned to work in the construction industry (21 of which due to domestic of environmental exposures), which gives a rate of 4.1 (95% CI 3.6-4.8) x 10(5) x year among construction workers. The asbestos fibre content detected in the lungs of 11 construction workers showed a mean of 1.7 x 10(6) fibres/g dry tissue (range 350,000-3 million) for fibres > 1 micro, almost exclusively due to amphibole fibres. 62% of the claims for compensation were granted but the percentage fell to less than 40% when claims were submitted by a relative, after the death of the subject. CONCLUSION: The prevalence of mesothelioma occurring among construction workers is high and is associated with asbestos exposure; the risk is underestimated by the subjects and their relatives. All mesotheliomas occurring among construction workers should be granted compensation for occupational disease.

[Asbestos fibre lung burden and exposure indices in asbestos-cement workers]. / Carico polmonare di fibre di asbesto e indici di esposizione cumulativa in lavoratori del cementoamianto.

BACKGROUND: In many previous studies, the asbestos fibres retained in the lung were regarded as a good index of cumulative occupational asbestos exposure. Twelve workers suffering from asbestos-related diseases and had been employed in an asbestos-cement factory operating from 1961 to 1994 underwent post mortem investigations in the course of a criminal law suit. OBJECTIVES: Samples of lung tissues were collected for electron microscopy analysis to measure the asbestos fibre burden of the lungs in workers with high exposure, and assess the possible correlation between asbestos fibre lung burden and the estimated levels of cumulative exposure. METHODS: Samples of lung parenchyma obtained from a consecutive series of 12 post-mortem examinations that were performed between 1994 and 2007and included 5 cases of malignant pleural mesothelioma, 4 lung cancers, 1 case of asbestosis and2 ofpleuralplagues, were collected, stored and analysed by SEM electron microscopy, according to the methods suggested by the current scientific literature. For each worker, all males, a detailed occupational history was reconstructed by means ofpersonal interviews; both the measurements of airborne asbestos fibresperformed by the factory in the 1970's and the duration of each single job in the plant were taken into account to estimate an individual cumulative exposure index. RESULTS: A wide variation of total asbestos fibre concentrations in the lung (1,320-118 million) was observed; in all 12 workers, the lung amphibole fibre burden exceeded 1,000,000 fibres per g/dry tissue, The highest values were detected in the mesothelioma cases, in which the mean fibre concentrations differed statistically (t=2.29, p=0.045) from the mean calculated for the other asbestos-related diseases; in 9 subjects only amphibole fibres were detected. There was a good correlation between total asbestos fibre concentration and cumulative exposure index (r=0.91, p<0.0001). CONCLUSION: This study, which was numerically the biggest ever performed in Italy for this category of workers, confirms a wide range of total asbestos fibre burden in heavily occupationally exposed workers and showed that of the asbestos-related diseases, the highest lung concentrations of asbestos fibres were reached in cases of mesothelioma. It was also observed that almost the entire lung burden consists of only amphibole fibres, all exceeding 1 million per gramme of dry tissue. This study tested a synthetic cumulative occupational exposure index, which appears to be well correlated to the level of exposure established by biological analysis.

[Malignant mesothelioma in garment sewing-machine workers]. / Mesoteliomi maligni nelle confezioni abbigliamento: un'ulteriore fonte di esposizione ad amianto.

BACKGROUND: Due to poor information collected through patient interviews, a considerable number of malignant mesothelioma (MM) cases still remain classified as "unknown" asbestos exposure in the Italian Mesotelioma Registry (Re.Na.M). At the same time, some occupational asbestos exposures, which were previously unknown, have been demonstrated in certain types of work, i.e., in agriculture and in the textile industry. OBJECTIVES: The aim of this research was to investigate the possible past occupational exposure to asbestos in clothing workers using sewing-machines. METHODS: The MM cases were collected from the Mesothelioma Registry of Brescia. Work histories were obtained via a standardized questionnaire. Investigations were conducted in sewing-machine maintenance workshop in order to collect information regarding the possible use of asbestos parts. In addition, the use of asbestos friction materials and the use of insulated asbestos materials was checked in the clothing divisions by interviewing the management and maintenance workers of two companies where cases of MM were observed. RESULTS: The Mesothelioma Registry of Brescia identified and collected 10 MM cases with past work in the clothing industry: 6 used sewing-machines and 4 were self-employed tailors. The search for asbestos materials gave positive results as the use of friction materials had been widespread since the 1950's in all types of sewing-machines; in addition, asbestos materials were used to insulate some parts of the ironing equipment and the steam pipelines. CONCLUSION: The results of this investigation suggest assigning at least "possible occupational asbestos exposure" to those cases employed in clothing manufacture since the 1950's, who used sewing-machines or pressing machines, according to the Re.Na.M guidelines. Other possible occupational exposures to asbestos in this working sector cannot be excluded; when the simple interview of patients does not reveal such exposures further investigations are needed in order to demonstrate all the possible circumstances of exposure.