Boron Isotope Characterization to Design a Frame of Hydrogeological Functioning of a Wetland System (Massif Central, France)

Multi-isotopic approaches (Li, Sr, O, H), combined with hydrological tools, have been already appliedfor tracing the water and dissolved-element fluxes in a peatland in Central France. Here, we applied B isotopes. The δ11B ratios increase from river draining basalts (∼ 0‰) up to springs bordering the peatland (>+25‰). Peatland groundwaters have intermediate δ11B: 7.8 to 19.4‰. This range is accompanied by an increase in the Ca contents between the river draining basalts and water in the peatland. In aδ11B vs.Ca/B diagram, the role of water rock interaction and present day fertilizer inputs is evidenced, as for Sr isotopes.