[Increase of nitrates in underground aquifers: study of a karstic basin in the Dijon area].

The purpose of the study was to explain the enormous increase of nitrates in the waters of river Bèze (Côte-d'Or) belonging to a well-defined karstic basin. This paper deals with surface and underground waters, pedologic formations and their rock base. It consisted in listing the oligoelements involved in the enzymic processes of nitrate reduction, the microflora and in determining the kinetics of denitrification by column perfusion. The presence of biodegradable carbon compounds is the governing factor of denitrification; their rapid lass related to new agricultural processes and the excessive use of nitrogene fertilizers are responsible for the enormous increase of nitrates observed.