A SUSTSAINABLE MANAGEMENT OF VOLCANIC ASH: A FOCUS ON ETNA VOLCANO

The fallout of volcanic ash (VA), in addition to being dangerous for human health, constitutes a significant economic damage for agricultural activities and causes imaginable difficulties for vehicle circulation, so much so as to induce the authorities to limit their speed and often even prohibit their use, at least until a sufficient level of safety can be guaranteed. The presence of such particles in the atmosphere, up to heights of several kilometers, also represents a very great danger for air navigation and often leads to closures of the airports involved and deviations of air traffic. Therefore, the fall of volcanic ash causes problems not only to the population living in that area, but also weighs on the municipal administrations, which must deal with getting rid of the volcanic ash, collecting it and dispose it in the safest way as soon as possible. This inconvenience found in all those areas where there are active volcanoes, has pushed the scientific community, in the perspective of the circular economy, to consider volcanic ash not as a problem but as a resource by reusing it as a replacement for raw materials used in various fields The present work aims to propose environmentally and economically sustainable management solutions for the valorization of volcanic ashes to solve the issues - deeply felt in the cities around the ETNA volcano - of managing sudden and tremendous quantities of ash produced by unpredictable eruptive events. Starting from a critical review of the literature in which the performance of VA applications has been analyzed, sustainable reuse solutions have been identified, with particular reference to use in agriculture. The volcanic ash collected during the eruptive events of ETNA Volcano in 2021 was characterized from a physical-chemical point of view with a specific focus on the leaching behaviour to verify their possible recovery. Moreover, a protocol for sustainable management and regulations compliance was devised for different reuse strategies. The different samples were characterized by analyzing the presence of light and heavy hydrocarbons, PCBs (polychlorinated biphenyls) and PCTs (polychlorinated triphenyls) and PAHs (polycyclic aromatic hydrocarbons), the Acid Neutralization Capacity (ANC) and the Total Organic Carbon (TOC). Furthermore, elemental analysis was performed by studying the pH, the residue at 105°C and the residue at 600°C. Subsequently, the analysis of metals and the leaching test to analyzing anions were performed. The characterization results were compared with the limits imposed by Italian legislation on recovery (Ministerial Decree 05-02-98 ) and by the discipline on fertilizers (D.Lgs 29-04-2010, n.75) demonstrating the feasibility of an alternative and sustainable use of volcanic ash in agriculture. The activities were conducted in collaboration between the University of Catania, National Institute of Geophysics and Volcanology, Cisma Ambiente S.p.A. and ENEA.