The membrane filter (MF) method for evaluating asbestos fibre concentrations was introduced in the 1960s. Before that time the midget impinger (MI) was used in North America, while the long running (LRTP) and regular thermal precipitator (TP) were used in the U.K. All studies from which estimates of long-term health risks can be derived (i.e. those with individual cumulative lifetime exposure estimates) were based on the now obsolete methods. The reliability of converting these indices of exposure to MF equivalent concentrations was reviewed. It was concluded that no overall single factor could be derived for the Quebec mining and milling industry. However, it has been possible to derive conversion factors at the individual mill and work area level. Applying these in one Quebec mortality study analysis based on all jobs held by persons in the cohort gave an overall MF/MI ratio of 3.6. An examination of the confidence intervals surrounding the Quebec data, ratios derived for other chrysotile mines by other investigators, and measurements of fibre concentrations in the 1970s suggest that this was probably not unreasonable. Side-by-side and other measurements were used to convert MI concentrations in the U.S. textile industry to MF fibre concentrations. While conversions involve considerable uncertainty, independent measurements of fibres in the lung tissues of workers from the U.S. textile plant and Quebec mills show that in lungs the ratios of the concentrations of chrysotile to those of tremolite are quite consistent with the ratio of assessed exposures to these fibres in the two industries. There is an apparently higher risk of mesothelioma in one Quebec mining area (Thetford Mines) than in another (Asbestos). A high concentration of fibrous tremolite has been found in the lungs of workers in Thetford. A method of evaluating the extent to which mesothelioma risk in the chrysotile mining industry might be explained by tremolite exposures was proposed. The slope of the lung cancer dose-response relationship for the textile industry is approximately 50 times that for the mining and milling industry. Available data on the length distributions of fibres from Quebec mines and mills (up to 5% > 5 microns) and the Charleston textile plant (up to 21% > 5 microns) and some marginal indication of longer fibres in tissues from Charleston workers suggest that further work specifically addressing differences in the size distributions of long fibres in these industries is needed.
The authors studied changes in several laboratory values of coal miners in Russian Federation, defined information value of these changes and suggested complex of methods for early preclinical diagnosis of negative effects caused by coal dust in the miners. Dust-related respiratory diseases were proved to develop by stages on molecular level.
The authors studied distribution of biochemical markers for HP, GC, EsD, AcP genes, polymorphism of GSTT1 (GST-theta 1), GSTM1 (GST-mu 1), locus WNTR of NOS3 gene (alleles A/B) in chronic dust bronchitis patients and in apparently healthy individuals. Genotypes EsD 1-2 and AcP bb individuals were proved to be most prone to the disease. Endogenous resistent factors for chronic dust bronchitis are genotypes GC 1-1, EsD 1-1, AcP bc.
One hundred thirty patients with Siberian silicosis occurring under exposure to large amounts of dust at labor in a siberian mine were analyzed for 67 clinical and 122 laboratory data. Eighty-eight of 130 patients are now alive, but 42 have already died. When they started work, 122 of the patients were under thirty years of age. The duration of work was 7 to 12 months for 17 patients, 13 to 18 for 43, and 19 to 24 for 40. Seventy-six of 99 patients were initially diagnosed with lung tuberculosis and 23 with silicosis. Almost all patients have complained of respiratory symptoms such as shortness of breath, cough, sputum, and cyanosis. All of the pulmonary function tests including %VC, FEV1.0/FVC, V25/height, RV, TLC, and DLco showed abnormal values. The chest roentogenograms showed 3 of type 1, 22 of type 2, 55 of type 3, and 124 of type 4. Of 124 type-4, large opacities, 84 were type A, 28 B, and 12 C. Of 416 small opacities, 144 were type P, 191 Q, and 81 R. The complications and secondary changes that appeared with progression of the disease were lung emphysema, hilar and mediastinal lymphnode enlargement, egg shell calcification in lymphnode, and bulla or bleb.
In miners anthracosilicosis is caused by chronic exposure to coal dust and is characterized by progressive development of the inflammatory process, the expressed disorders of lipid metabolism, and immunodeficiency. In the experiment we revealed the stages of anthracosilicosis development according to which adequate measures of prevention and correction of the disorders caused by long exposure of an organism to coal dust are recommended.
Studies covered incidence of coronary heart disease, its risk factors and features of constitutional types among Kouzbass coal miners suffering from anthracosilicosis and chronic dust bronchitis. Findings are reliably higher incidence of coronary heart disease among coal miners having lung diseases caused by dust. Coronary heart disease among the miners with anthracosilicosis is favored by arterial hypertension, overweight and hypersthenic constitutional type, that among those with dust bronchitis is favored only by overweight.