Hydrodynamic and geochemical behavior of a karst aquifer system exposed to contamination: analysis of the response of the Moresco Springs (Apuan Alps, Italy) to rainfall.

The Baccatoio Stream basin (Apuan Alps) was subjected to numerous investigations linked to the presence of abandoned mines and related acid mine drainages. This study aims to achieve new insights into water circulation in carbonate aquifers feeding three of the major springs of the area (Moresco springs: VSMOA, VSMOS, VSMOG). VSMOA and VSMOS show evidences of hydraulic connection with Baccatoio stream, contaminated by acid mine drainages. The study focused on springs chemical and isotopic variations induced by a rainfall event. Some general conclusions can be drown: (i) the hydraulic connection between Baccatoio stream and VSMOA-VSMOS seems to be confirmed; (ii) during rainfall events, infiltrated rainwater seem to directly contribute to the perturbation of VSMOA-VSMOS; (iii) different flow fractions feeding VSMOAVSMOS after rainfall pulse were quantified; (iv) VSMOG did not show any perturbation linked to the rainfall.