Tracing sources and fate of nitrate in multilayered karstic hydrogeological catchments using natural stable isotopic composition (δ15N-NO3− and δ18O-NO3−). Application to the Toulon karst system (Dordogne, France)

Guillaume Lorette, Mathieu Sébilo, Damien Buquet, Roland Lastennet, Alain Denis, Nicolas Peyraube, Veronique Charriere, Jean-Christophe Studer