Risk of silicosis in cohorts of Chinese tin and tungsten miners, and pottery workers (I): An epidemiological study

Abstract

The observed differences in the risk of silicosis among the three cohorts suggest that silica dust characteristics, in addition to cumulative respirable silica dust exposure, may affect the risk of silicosis.

Risk of silicosis in cohorts of Chinese tin and tungsten miners and pottery workers (II): Workplace-specific silica particle surface composition

“…These respirable dusts were available for surface analysis from 13 of the 20 worksites involved in the companion epidemiological cohort mortality study of silicosis risk [Chen et al, 2005]. Five of the seven worksites in the epidemiology study without dust sample surface analysis were tungsten mines in the same geographic and geologic region as two of the tungsten mines that were sampled; one of the worksites was a tin mine and one a pottery.…”

“…That study also found that crystalline silica dust particles extracted from coal mine dust did not initiate fibrogenic activity over the lifespan of the animal model; but those particles were promptly fibrogenic after strong acid digestion of clay from the particles surfaces. The effect of silica particle surface composition on silicosis disease risk has been investigated in the companion paper [Chen et al, 2005]. Silicosis disease risk and respirable silica dust surface composition were compared between metal mines and pottery workplaces in China for which a large medical registry for silicosis was available and for which representative samples of workplace dusts could be obtained.…”

Health effects of occupational exposure to crystalline silica in the light of current research results

“…Health effects of exposure to crystalline silica Nr 6 801 The research on the incidence of silicosis in the people exposed to crystalline silica has continued for several decades and the results have been published in several review papers (3,(10)(11)(12) ×years is estimated to range from 1% to 20% (median: 5%) (16,19,22,23,26). In the case of higher doses, from 4 to 6 mg/m 3 ×years, corresponding to 40 years of exposure to crystalline silica concentration equal to 0.1-0.15 mg/m 3 , the risk of silicosis ranges from several per cent to several ten percent (15,16,26).…”

“…In the case of higher doses, from 4 to 6 mg/m 3 ×years, corresponding to 40 years of exposure to crystalline silica concentration equal to 0.1-0.15 mg/m 3 , the risk of silicosis ranges from several per cent to several ten percent (15,16,26). The highest cumulative exposure of over 6 mg/m 3 ×years involves the risk of 8-77% (the average around 40%) (17)(18)(19)23). The differences in the level of the risk of silicosis estimated in various studies may be caused by several factors: n The adopted criterion for diagnosing the silicosisrelated changes in the radiographic image of the lungs (shading category 1/0, 1/1, 2/1 or ≥ 2/1 according to the ILO 2002 (9)) (15,16,18,(22)(23)(24).…”

“…The modification of the surface properties of such particles by coal mine dusts or clay dusts, i.e., minerals, which cause occlusion of the silica particles, as well as aluminum salts and metallic iron, can lead to reduction of biological activity of crystalline silica (34). It is believed that the weaker fibrotic effect of such dusts results in reducing the risk of silicosis among the workers employed in factories manufacturing ceramic products (14,19) and in coal mines (15).…”