Boron Isotope Variation During Flood Events in a Mediterranean Basin: Tracer of the Water Compartments (Hérault, S. France)

Boron isotopes were measured during 3 flood events at the outlet of the Hérault watershed in complement with Sr isotopes. The main water sources (i.e. karst aquifer and the tributaries) were also constrained in high and low flows. Boron isotopes are controlled both by natural and anthropogenic inputs (sewage effluents and/or fertilizers) whereas Sr isotopes trace the various lithologies in the basin. The signature of the Hérault River during flood events presents isotopic variations as large as 15 delta units for boron isotopes, revealing the various contributions of the water compartments according to the rainfall intensity, duration and location.