Integrated hydrogeochemical and geophysical surveys for a study of sea-water intrusion

The CFTA Department of the University of Palermo in collaboration with ARPASICILIA has carried out a study of the sea intrusion phenomenon in the aquiferbetween the cities of Marsala and Mazara del Vallo (south-western Sicily) usinggeophysical techniques (TDEM, ERT and MASW) and geochemical analysis of wellwater. The aim of the research was to optimize the acquisition techniques, dataprocessing and data interpretation for the geometry reconstruction of aquifers, theircharacterization, and the determination of concentration of pollutants. The analysis ofthe geophysical results reveals the existence of very low resistivity values incorrespondence of the area from the coastline to a kilometer inland. Obviously, in thisarea, the sea intrusion is more pronounced. Furthermore, major element contents andphysical-chemical parameters of sampled water testify that the main process thatdefines the groundwater geochemistry in this area is a mixing between the carbonaticaquifers and the marine component. A significant contamination of nitrate andsulphate is also present. About 90% of the sampled wells were contaminated over theItalian legislation limits.