Nonfibrous mineralogical analysis of bronchoalveolar lavage fluid from blast-furnace workers.

Steelworkers are exposed to many pollutants, and they are at risk for developing lung cancer. We demonstrated previously that steelworkers may be subject to an occult exposure to amphiboles in the plant environment. In the current study, we further analyzed bronchoalveolar lavage fluid of steelworkers by measuring intramacrophagic trace-metal content and nonfibrous mineral particles, using the particle-induced x-ray emission method and electron microscopy, respectively. Forty-seven blast-furnace workers and 45 healthy white-collar workers volunteered for this study. Significantly increased levels of iron, titanium, zinc, and bromine were found in the steelworkers, and levels of lead, chromium, arsenic, and strontium tended to increase in the macrophages and bronchoalveolar lavage fluid of the steelworkers. Nonfibrous particles, including illite, kaolinite, talc, chlorite, amorphous silica, quartz, iron (compounds), and titanium hydroxide, were found in both groups, but the particle number per ml bronchoalveolar lavage fluid (particularly iron hydroxides and silicates) was more pronounced in blast-furnace workers. These elements and particles may act synergistically with other occupational carcinogens and cigarette smoke, the result of which may be an increased incidence of lung cancer in the ironsteel industry.

Environmental asbestotic pleural plaques in northeast Corsica: correlations with airborne and pleural mineralogic analysis.

We report a prevalence study of environmental pleural plaques in subjects over 50 years old from the northeastern Corsican village of Murato, built on asbestos surface deposits. The percentage of plaques was 41%, versus 7.5% in the control village of Vezzani. Although surface deposits contain both chrysotile and tremolite, airborne pollution and asbestos lung burden of exposed inhabitants consist essentially of tremolite as assessed by transmission electron microscopy (TEM). However, TEM analysis of the parietal pleura of three animals bred in exposed areas showed a predominance of short fibers of chrysotile. The respective roles of tremolite and chrysotile in inducing pleural plaques in Corsica should thus be considered.

Environmental pleural plaques in an asbestos exposed population of northeast Corsica.

The purpose of this study was to determine whether the inhabitants of villages environmentally exposed to asbestos, in northeast Corsica, had a higher incidence of pleural plaques. X-rays were obtained from subjects aged over 50 yrs, with no occupational exposure to asbestos or history of pleural disease, in one village exposed to asbestos, Murato, and a nonexposed, control village, Vezzani. In addition, the mineral content of the air and parietal pleura of animals in the exposed zone was studied, using transmission electron microscopy. The incidence of bilateral pleural plaques in the exposed population was 41%, as compared to 7.5% in the nonexposed population (p < 0.00001). The levels of airborne tremolite were higher in Murato (6-72 ng.m-3) than in Vezzani (< 1 ng.m-3), but chrysotile levels were similar. Significant numbers of chrysotile and tremolite fibres were identified in the parietal pleura of animals from the exposed village. This study confirms the well-known correlation between bilateral pleural plaques and environmental exposure to low levels of asbestos.

[Environmental mesotheliomas in northeast Corsica]. / Les mésothéliomes environnementaux en Corse du nord-est.

Since 1980, we have collected fourteen cases of mesothelioma induced by environmental exposure to asbestos, going back to childhood in patients from north-east Corsica, in a region which was remote from the asbestos mine of Canari. There were eight men and six women with a mean age of 69.5 +/- 4 years. Six patients presented with bilateral calcified pleural plaques as evidence of environmental exposure. The mineral analysis carried out on five patients (four had thoracoscopies and one an alveolar lavage), showed a moderate deposit of chrysotile (0.3 to 3.4 x 10(6) fibres per gram of dry tissue), and elevated level of tremolite (1.4 to 62 x 10(6) fibres/g). The ambient dosage of asbestos has confirmed the existence of environmental pollution by chrysotile fibres and above all by tremolite. In addition, the same type of fibres have been identified in the parietal pleural of animals subjected to the same risk. In this region, the risk is estimated, on the basis of our results, as 10 cases of mesothelioma per 100,000 inhabitants per year.