Documents anthophyllite 5 results

"Objectives: The prevalence of asbestos-related radiographic abnormalities was surveyed among Finnish construction, shipyard, and asbestos industry workers.

Methods: The radiographic screening focused on active and retired workers who were under the age of 70 years and had been employed for at least 10 years in construction or for at least 1 year in shipyards or in the asbestos industry. In 1990-1992, 18,943 people participated in an X-ray examination of the lungs and an interview on work history and exposure. The criteria for a positive radiological finding were (i) small irregular lung opacities clearly consistent with interstitial pulmonary fibrosis (ILO 1/1 or higher), (ii) lung opacities indicating mild pulmonary fibrosis (ILO 1/0) with unilateral or bilateral pleural plaques, (iii) marked adhesions with or without thickening of the visceral pleura, or (iv) findings consistent with bilateral pleural plaques.

Results: Fulfilling the criteria were 4133 workers (22%) (22% from construction, 16% from shipyards, and 24% from the asbestos industry). The radiological findings included signs of pulmonary fibrosis (3%), changes in the visceral pleura (7%), bilateral plaques (17%), and unilateral plaques (10%). Occupational disease was diagnosed according to the Finnish insurance regulations for three-fourths of those referred for further examinations, 96% being abnormalities in the pleura and 4% being asbestosis.

Conclusions: Exposure to asbestos dust has been common in ordinary construction work, and, consequently, radiographic abnormalities (mostly pleural) occur frequently among active and retired construction workers."

"Objectives The study analyzed the recent trend in the incidence of mesothelioma in Finland and evaluated the coverage of reporting work-related mesothelioma.

Methods The incidence of mesothelioma in 1960--1995 was retrieved from the Finnish Cancer Registry, and the number of asbestos-associated work-related mesotheliomas were taken from the Finnish Register of Occupational Diseases.

Results The annual number of mesotheliomas increased rapidly in 1975--1990. In the 1990s, the age-adjusted incidence remained relatively stable for Finnish men. The annual number of cases still increased among men over 65 years of age, but decreased slightly among men under 55 years of age and among women. About 35 annual cases were diagnosed among the men and 10--15 among women in the mid-1990s. The reporting of work-related mesotheliomas improved during the Finnish asbestos program in 1987--1992. In 1993--1995 about 30 annual cases (ie, about 90% of all pleural and 50% of the peritoneal mesotheliomas in men) were reported to be work-related.

Conclusion The increasing trend in the incidence of mesothelioma in Finland slowed down in the 1990s, and the maximum of asbestos-related cases in the early 2000s will probably be clearly less than the 100 annual cases estimated in the early 1990s. If the observed trend continues up to 2010, about 40--50 cases among men and 10--20 among the women will then be diagnosed annually. Altogether 40--50 of these cases would be related to occupational asbestos exposure."

The mineral phases and chemical and physical characteristics of the chrysotile-A (12001295), chrysotile-B, crocidolite (12001284), amosite (12172735), and anthophyllite (17068789) samples prepared by the International Union Against Cancer (UICC) in 1966 were examined in this study. Mineral phases were determined through the use of X-ray diffraction (XRD). Anthophyllite, talc (14807966), and nonfibrous minerals were detected in samples of chrysotile-A. The quantity of anthophyllite in chrysotile-A was estimated at 2%. The proportions of chrysotile in chrysotile-A and chrysotile-B were 94% and 92%, respectively. Amosite and crocidolite samples each contained about 1% quartz (14808607). The anthophyllite sample contained about 5% each of chlorite and mica, and about 20 to 30% talc. Overall, the chemical compositions of the samples indicated high purity. Chrysotile-B contained higher concentrations of some constituents than chrysotile-A, while anthophyllite contained high concentrations of oxides, indicating an impurity. Thermal analysis of the chrysotiles and anthophyllite indicated dehydroxidation and recrystallization. No mineral impurities were detected in the amosite and crocidolite samples by thermal analysis. Analytical transmission electron microscopy revealed that the chrysotiles consisted of thin, curly fibrils, fiber bundles, and platy materials, while amosite, crocidolite, and anthophyllite consisted of wider, rectangular fibers. The mean lengths of the chrysotile and crocidolite fibers were shorter and exhibited less variability than those of the amosite and anthophyllite samples. The mean fiber widths of the chrysotiles were less than those of amosite, crocidolite, and anthophyllite. The authors conclude that further study is necessary, since the characteristics of the UICC asbestos samples measured with modern equipment and techniques differ from those that were established years ago.

"Ten chrysotile bulk samples originating from six Chinese chrysotile mines were studied for amphibole fibres. Five of the mines operate on ultramafic rocks whereas one exploits a dolomite-hosted deposit. The asbestos fibre content in lung tissue was examined from seven deceased workers of the Shenyang asbestos plant using these raw materials. The bulk samples were pretreated with acid/alkali-digestion, and thereafter, scanning and transmission electron microscopy, X-ray microanalysis, selected area electron diffraction and X-ray powder diffractometry were used to identify the minerals. Sample preparation of lung tissue involved drying and low-temperature ashing. All of the bulk samples contained amphibole fibres as an impurity. The amphibole asbestos contents were between 0.002 and 0.310 w-%. Tremolite fibres were detected in every sample but anthophyllite fibres were present only in the sample originating from the dolomite-hosted deposit. In comparison, anthophyllite (71%), tremolite (9%) and chrysotile (10%) were the main fibre types in the lung tissue samples indicating faster pulmonary clearance of chrysotile fibres. The total levels ranged from 2.4 to 148.3 million fibres (over 1 {micro}m in length) per gram of dry tissue, and they were consistent with heavy occupational exposure to asbestos."