[Three cases of pleural mesothelioma and environmental pollution with tremolite outcrops in Lucania].

In a circumscribed rural area of Lucania (Italy) three cases of pleural mesothelioma have been identified: two men, 83 and 52 years old and a 78 year-old woman, who all had in common the fact of being shepards in that area. Possible asbestos pollution sources have been sought: we have immediately excluded an asbestos manufactured articles pollution, however we have highlighted the presence of "green stones", which had always been known to the local inhabitants and which, in three subsequent campains of collecting and chemical-mineralogical investigations, have resulted partly constituted by amphibole asbestos, classified as tremolite. Official institutions are organising a series of initiatives to verify the hypothesis of a causal relationship between the presence of tremolite and the cases of pleural mesothelioma, and preventive initiatives aimed at reducing exposure and to a sanitary surveillance.

[Quantitative analysis of low concentrations of cristobalite in thin layers by x-ray diffraction].

A new x-ray diffraction procedure for the determination of cristobalite in the presence of amorphous silica is described. The standards are obtained by deposition of thin layers of watery suspensions of cristobalite and amorphous silica mixtures on silver or lead disks or cellulosa filters. Six calibration curves are then calculated to reduce weight and sampling errors.

[Identification, using x-diffractometry, of chromium, lead and zinc compounds in pigments of protective paints].

The application of diffractometric techniques for the identification of crystalline compounds which are contained in paint pigments and are important from the hygienic point of view, is described. Particularly, it is possible to identify lead and zinc chromates either on untreated pigments, or on filters of air samples of work-places used for spray painting.

[Asbestos minerals: their recognition and determination].

Fibers of amphibolic and serpentinic asbestos may be optically distinguished by the method proposed by the AA. The method is based on the observation at the microscope in reflected fluorescence of fibers of asbestos previously treated with a fluorochrome colouring agent; it can be applied for the individual counting of fibers on the filters used for checking the environmental air and has already been applied with good results in asbestic cement factories.