The wild rat as sentinel animal to detect potential risk for human environmental exposure to asbestos: seeking latent sources in Casale Monferrato (NW Italy).

Asbestos have been incorporated into many different products since its discovery, centuries ago. Countless applications of asbestos result from their many unique characteristics. It has long been recognized the link between their breathing and the pulmonary related diseases (asbestosis, malignant mesothelioma and lung cancer) in occupational exposed workers. For this reason asbestos have been banned in many countries, including Italy (L.257/92). Also a particular kind of exposure, specifically anthropogenic environmental exposure, shown his dangerousness, e.g. in the areas where asbestos industries were active. At present, the dose-response relationship has no a threshold and the relationship between exposure to environmental sources of asbestos and health effects still represents an open issue. In Casale Monferrato city (Piemonte Region, NW Italy), the biggest Italian plant of Eternit® (a mixture of cement-asbestos) was active from 1907 to 1986 but sources of exposure may still exist in the environment and they can represent a potential of human exposure. The idea was to identify the possible presence of previously unrecognized asbestos sources, by measuring the asbestos fibre content in the lungs of wild rats (used as sentinel animals). Measurement of the lung fiber burden in wild rats has proved feasible. Previously we carried out a pilot study that demonstrated that it was possible not only to detect, but also to characterize asbestos fibers both qualitatively and quantitatively. Casale Monferrato district has been divided in a grid with 61 cells (200 x 200 m). Neighborhood with different degree of priority have been identified, based on technological processes and asbestos transports, historically reported within the city. We established to capture a minimum of 5 wild rats in each cell with a multi-capture device and for each pool constituted by 5 lungs, SEM–EDS investigation will be carried out. Until now, 18 wild rats have been captured in five different cells but only in one of them, the completed pool has been collected. The SEM-EDS investigation of this pool showed 40800 fibers per gram of dry weight (ff/gdw) of asbestos tremolite and 5100 ff/gdw of asbestos grunerite, i.e. a burden of asbestos both from natural and anthropic source. In April this project titled “Sentinel animals for asbestos”, was introduced to the citizenry and authority of Casale Monferrato with the aim to make the inhabitants aware of our research, and to involve them to obtain directly indication about the sites where rats are present to increase their capture. A Facebook page for this aim has been opened and promoted.