aaAsbestos comprises a group of six hydrated silicate minerals capable of forming very thin fibres: chrysotile, crocidolite, amosite, anthophyllite, tremolite and actinolite [1]. Chrysotile belongs to the serpentine group and the other five to the amphibole group of minerals. Chrysotile fibre bundles split easily and magnesium can be leached under weak acid conditions. These factors may contribute to the lower biopersistence of chrysotile in the lungs.

In Western Europe, Scandinavia, North America, and Australia the manufacture and use of asbestos products peaked in the 1970s. Current incidences of mesothelioma range from 14 to 35 cases/million/year in 11 industrialized countries that had used asbestos 2.0 to 5.5 kg/capita/year about 25 years earlier. A significant linear correlation (r = 0.80, p 0.01) exists between the two variables. Accordingly, about 170 tons of produced and consumed asbestos will cause at least one death from mesothelioma, most often as a consequence of occupational exposure.

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The objective of the present study is to determine the feasibility of chest computed tomography (CT) in screening for lung cancer among asbestos-exposed workers.In total, 633 workers were included in the present study and were examined with chest radiography and high-resolution CT (HRCT). A total of 180 current and ex-smokers (cessation within the previous 10 yrs) were also screened with spiral CT. Noncalcified lung nodules were considered positive findings. The incidental CT findings not related to asbestos exposure were registered and further examined when needed.Noncalcified lung nodules were detected in 86 workers. Five histologically confirmed lung cancers were found. Only one of the five cancers was also detected by plain chest radiography and three were from the group of patients with a pre-estimated lower cancer probability. Two lung cancers were stage Ia and were radically operated. In total, 277 individuals presented 343 incidental findings of which 46 required further examination. Four of these were regarded as clinically important.In conclusion, computed tomography and high-resolution computed tomography proved to be superior to plain radiography in detecting lung cancer in asbestos-exposed workers with many confounding chest findings. The numerous incidental findings are a major concern for future screenings, which should be considered for asbestos-exposed ex-smokers and current smokers.

To obtain reference values for blood and serum manganese levels, blood specimens were collected from 29 men and 36 women. Mn in blood showed a normal distribution; its upper 97.5% limit in blood was 0.38 mumol/l. Mn in serum showed a skewed distribution, which did not differ from the normal one after logarithmic transformation. The respective reference limit was 19 nmol/l. In both specimens, the levels of Mn were significantly lower in men than in women. To obtain reference values for Mn in urine, midday urine specimens were collected from 58 men and 96 women. Mn in urine also showed a skewed distribution, and the upper 97.5% limit was 38 nmol/l. The levels of Mn in blood and urine were statistically significantly higher in manual metal arc (MMA) welders of mild steel (MS) than in the reference populations. Five MMA/MS welders were subjected to a further study in which the ambient intramask Mn levels and urinary Mn excretion were monitored throughout a full working week. For two welders the correlation of Mn in urine specimens voided in the afternoon was good with the before noon Mn concentrations in the hygienic measurements; for the rest the correlation was minimal. Mn in diurnal urine specimens collected in six portions showed fluctuation if specific gravity or creatinine in urine was used to standardize for the urinary flow, but it was less evident for urinary Mn excretion rate. Our results seem to indicate that the measurement of Mn in urine or blood may be used for monitoring Mn exposure in MMA/MS welders only at the group level.