I am working in chemical potamology. I am interested by the global role of chemical weathering in the Earth’s chemical engine. I focus on the « drainage basin » approach both at large scale and small scale. I am especially interested by the geochemistry of the sediments transported by rivers and produced by chemical weathering in soils. I am involved in the national and international organization of a network of drainage basins (known as the Critical Zone Exploration Network). My tools are elemental and isotopic geochemistry. I have developped or participated to the developement of several techniques for measuring precise isotopic abundances in natural materials (B, Li, Zn, Mg) and applied these techniques to study rainwater, riverwater, sediments, rocks. I have been involved in the adventure of using boron isotopes in carbonates as a tracer of paleo-pH of the ocean. More recently, I got interested in using isotopes to trace pollution.