http://hdl.handle.net/2122/165 Search the Channel search http://www.earth-prints.org/simple-search http://hdl.handle.net/2122/4131 Title: GEOCHEMICAL CHARACTERIZATION OF THERMAL AND COLD GROUNDWATERS OF METHANA PENINSULA (PELOPONNESUS, GREECE) <br/> <br/>Authors: D'Alessandro, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Brusca, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Kyriakopoulos, K.; University of Athens, Dept. Geology and Geoenvironment; Bellomo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Michas, G.; University of Athens, Dept. Geology and Geoenvironment; Papadakis, G.; University of Athens, Dept. Geology and Geoenvironment <br/> <br/>Editors: Migiros, G.; Agricultural University of Athens, Dept: Sciences; Stamatis, G.; Agricultural University of Athens, Dept: Sciences; Stournaras, G.; University of Athens, Dept. of Geology and Geoenvironment <br/> <br/>Abstract: A comprehensive hydrogeochemical study of the cold and thermal groundwaters of the presently quiescent volcanic system of Methana was undertaken collecting 59 natural water samples during the period 2004-2007. Methana is a peninsula whose climatology and hydrology can be compared to the nearby small islands of the Aegean Sea. Similarly the chemical and isotopic composition of its water is dominated by the mixing of seawater with meteoric water. But the simple mixing trend is modified by water-rock interaction processes, enhanced by the dissolution of endogenous CO2, leading to strong enrichments in Alkalinity, Calcium, Barium, Iron and Manganese. Tue, 07 Oct 2008 22:58:59 GMT http://hdl.handle.net/2122/3749 Title: Flow changes and geochemical anomalies in warm and cold springs associated with the 1992-1994 seismic sequence at Pollina, central Sicily, Italy <br/> <br/>Authors: Favara, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Grassa, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Madonia, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Valenza, M.; Dipartimento CFTA Unviersità di Palermo <br/> <br/>Abstract: During a three-year discontinuous geochemical monitoring of some warm springs and cold discharges located in central-northern Sicily, some hydro-geochemical changes were observed. Excluding a possible related to a moderate seismic activity were accidentally identified. The observed anomalies showed amplitudes that were modulated by the different geometries and volumes of the feeding aquifers. A poroelastic aquifer contraction, a shaking-induced dilatancy theory as well as seismogenetic-induced changes in the properties of the aquifers have been proposed as possible mechanisms for the water flow and hydro-geochemical changes. These preliminary results could be used to design a monitoring network aimed at surveilling the seismic activity of the studied area from a geochemical standpoint. Sun, 29 Oct 2006 22:58:59 GMT http://hdl.handle.net/2122/2724 Title: Fluid geochemistry investigations on the volcanic system of methana <br/> <br/>Authors: D'Alessandro, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Brusca, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Kyriakopoulos, K.; University of Athens; Margaritopoulos, M.; University of Athens; Michas, G.; University of Athens; Papadakis, G.; University of Athens <br/> <br/>Abstract: An extensive geochemical survey on the fluids released by the volcanic/geothermal system of Methana was undertaken. Characterization of the gases was made on the basis of the chemical and isotopic (He and C) analysis of 14 samples. CO2 soil gas concentration and fluxes were measured on the whole peninsula at more than 100 sampling sites. 31 samples of thermal and cold groundwaters were also sampled and analysed to characterize the geochemistry of aquifers. Anomalies referable to the geothermal system, besides at known thermal manifesta-tions, were also recognized at some anomalous degassing soil site and in some cold groundwater. These anomalies were always spatially correlated to the main active tectonic system of the area. The total CO2 output of the volcanic system has been preliminary estimated in about 0.2 kg s-1. Although this value is low compared to other volcanic systems, anomalous CO2 degassing at Methana may pose gas hazard problems. Such volcanic risk, although restricted to limited areas, cannot be neglected and further studies have to be undertaken for its better assessment Sat, 28 Apr 2007 22:58:59 GMT http://hdl.handle.net/2122/2590 Title: Human fluorosis related to volcanic activity: a review <br/> <br/>Authors: D'Alessandro, Walter; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia <br/> <br/>Editors: Kungolos, A.; University of Thessaly, Greece; Samaras, C.P.; TEI of West Macedonia, Greece; Brebbia, Carlos A.; Wessex Institute of Technology, U.K.; Popov, V.; Wessex Institute of Technology, U.K. <br/> <br/>Abstract: Fluorosis is a widespread disease related to ingestion of high levels of fluorine through water and food. Although sometimes of anthropogenic origin, high levels of fluorine are generally related to natural sources. One of the main sources is represented by volcanic activity, which releases magmatic fluorine generally as hydrogen fluorine through volcanic degassing. For example, Mt. Etna in Italy is considered the greatest point source at the global scale, releasing on average 70 Gg of HF each year. But the impact of fluorine on human health is highly dependent on its chemical state, which means that high rates of release not necessary point to high impacts. The major pathway of magmatic fluorine to humans is in the form of fluoride ion (F-), through consumption of contaminated vegetables and drinking water. Contamination can happen either through direct uptake of gaseous HF or through rainwaters and volcanic ashes. Furthermore hydrogen fluoride, being one of the most soluble gases in magmas, exsolves only partially (< 20%) during volcanic activity. Volcanic rocks thus contain high levels of fluorine, which are transferred to groundwaters through water-rock interaction processes in the aquifers. Large magmatic provinces, like for example the East African Rift Valley, are therefore endemic for fluorosis. Finally a literature review of volcanic related fluorosis is given. Sat, 29 Oct 2005 22:58:59 GMT