Isotopic features of Emilia-Romagna region (North Italy) groundwaters: Environmental and climatological implications

•Groundwaters and rivers isotopic monitoring allows a detailed knowledge of aquifers.•Most groundwaters in the southern Po valley are very ancient or palaeowaters.•Most groundwaters of the southern Po valley infiltrated under significantly different climates.•Old groundwaters withdrawal induces land subsidence.

Summary18O/16O, D/H, tritium and carbon isotopes were analysed together with the main geochemical parameters of selected wells of groundwaters in the Emilia-Romagna region. The isotope data collected in a three-year monitoring program of surface waters allowed a subdivision of the studied region within the main feeding areas of the Po and Apennine Rivers. The isotopic investigation demonstrated the existence of palaeowaters hosted in deep aquifers in the plains and their overexploitation, which induced land subsidence phenomena. Groundwater stable isotopes have been utilized as a proxy for temperature and have shown significant atmospheric temperature variations over the past 30,000 years.