Hydrochemical and qualitative assessment of natural water spring in southern Italy

Groundwater represents a natural resource of great socio-economic importance for the entire southern Italy, where it is used for both irrigation and drinking purposes. Knowledge of the complex hydrogeological environment, of the chemical composition of waters and of the interpretation of geochemical maps allows the definition of flow domain, groundwater quality and degradation processes affecting the aquifers. The present paper offers a large qualitative assessment of water springs falling within the Crati river basin in Calabria, southern Italy, which is the largest basin in the region with an area of 2447.7 km2 and a complex lithology. 190 samples of water springs, located over 300 m a.s.l., were collected and analysed. For each sample, physical (i.e. pH, water temperature, conductivity) and chemical parameters, such as major cations (Ca2+, Mg2+, Na+, K+) and major anions (SO42-, Cl-, HCO3-), were evaluated. The physical and chemical tests allowed the characterization of the hydrochemical facies of the sampled waters by means of the Langelier-Ludwig diagram. Moreover, the relationship between water temperature and altitude of the water springs has been assessed as well as the one between conductivity and altitude. Due to the extension of the basin, the investigated area was split into 5 sub-areas, with different hydrochemical behaviour. Results showed a good quality status of the water springs, where the hydrochemical facies of bicarbonate-alkaline type is predominant, and allow us to identify the chemical and physical behaviour of groundwater in relation with the several lithologies present in the sub-areas.