Groundwater quality assessment of the Limnos Island Volcanic Aquifers, Greece.

Limnos Island in Greece, which has been the subject of extensive hydrogeological research, contains confined volcanic aquifers that overlie impermeable flysch. Groundwater salinization is usually the effect of seawater intrusion, and results from a combination of factors such as low annual areal precipitation and exploitation of aquifers for civil, commercial, and agricultural purposes. Areas with intense agricultural activities have also increasingly observed these effects. A geochemical evaluation on the basis of multiple ion (Ca2+, Mg2+, Na+, K+, HCO3-, Cl-, SO42-, NO3-) concentrations and physicochemical parameters distribution revealed that ion exchange is the dominant hydrogeochemical process. However, the enrichment of groundwater in potassium and magnesium results from rock and mineral weathering and dissolution.