Application of quantitative hydrogeological methodologies in northern sector of Vulsini

Perythirrenic volcanic aquifers of Central Italy are important resources for the local water supply. The optimal management of this resource is closely related to the knowledge of groundwater hydrological dynamics. The increasing urbanization, industrialization and agricultural withdrawals lead to several management problems such as the depletion of groundwater and deterioration of water quality. Data about pronounced decreasing in springs discharge and in piezometric levels were described in these aquifers during the last twenty years (Capelli et al. 2005). A detailed hydrogeological survey was performed in umbrian sector of Vulsini Mounts to evaluate the quantitative conservation of the drinking resource in compared to previous works (Pagano et al. 2000, Capelli et al 2005). Several authors focused their attention on natural contamination problems of volcanic aquifers exploited for water supply. Most of studies concern water quality lowering by fluorine and arsenic occurrence due to geogenic contamination. On the contrary shallow aquifers water quality is often affected by anthropogenic activities, i.e. common contamination is due to nitrate in agricultural territory or heavy metal pollution close to industrial areas. Arpa Umbria detected anomalous concentrations of aluminum and iron in volcanic aquifer of the area near Orvieto in January 2010. Analyzed samples did not fulfil guidelines for water human consumption (98/83/EC implemented in Italy with D. Lgs 31/2001), then the authorities forbid the use of public water for drinking use.Al and Fe occur as colloids according to detected pH (6,5-7,5) and oxidizing Eh conditions. Another study area, characterized by similar volcanological and hydrogeological features and by the same colloids contamination in groundwater, was searched to understand similarities in the causes and processes of natural contamination of shallow aquifers near Orvieto. The second monitoring area was detected on the NE flank of Roccamonfina Volcano (Campania Region, Central Italy).