Carbonate aquifers threatened by legacy mining: hydrodynamics, hydrochemistry, and water isotopes integrated approach for spring water management

•Different groundwater flow systems feed adjacent carbonate springs.•A Tl-polluted stream threatens the shallow aquifer feeding two carbonate springs.•Groundwater stored in deep carbonate aquifers are more protected from contamination.•Water isotope signature enables individuating the main aquifers recharge area.•Integrated approaches support groundwater management in karst environments.