Airborne dispersion of asbestos fibers induced by serpentinites mining: a simulation in the Pievescola area (Tuscany, Italy).

In Italy, the environmental hazard related to asbestos is still high, also due to airborne dispersion of fibers as a consequence to mining activities into asbestos-bearing rocks, as serpentinites or basalts. The Ministerial Decree 14/05/1996 provides a method to define the hazard deriving from the exploitation of the asbestos-bearing rocks quarrying, but the proposed procedures are unclear from a geologic point of view, and not so effective for a precise assessment. We present an integrated approach based on geological, mineralogical and petrographical standard investigations on serpentinites and we test a model of airborne dispersion of fibers in order to propose more effective procedures in order to assess the asbestos-related hazard. The adopted approach consists of 5 successive steps: 1) detailed structural mapping and collection of samples representative of the outcropping rocks, 2) petrographical study of selected thin sections of serpentinites with the aim to assess the presence of fibrous minerals, 3) X-Ray powder diffraction analyses for the identification of the species of fibrous minerals, 4) determination of the Index of Release according to the Ministerial Decree 14/05/1996 in order to determine the amount of fibrous minerals released by crushing of the asbestos-bearing serpentinites and 5) modelling of the airborne dispersion of asbestos fibers by the quarrying activity based on the data collected in the previous steps. This integrated approach is based on standard geological techniques that can be applied not only by researchers but also by geological consultants and requires standard equipment that are commonly found in public and private laboratories. This approach has been simulated for an area located west of Pievescola, south of Casole d’Elsa (Tuscany), where no quarrying activity occurs or is scheduled for the future. According to the simulation performed in the Pievescola area, this integrated approach can be regarded as effective, even if liable of improvements. The implications of the adopted approach allow to identify valuable procedures to minimize the asbestos-related hazard. Particularly, the procedures adopted can be able to provide useful suggestions to make more effective the present- day legislation