Jérôme Molénat

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In catchments with impervious bedrock, the nitrate concentrations in streamwater often show marked seasonal and small inter-annual variations. The inter-annual trends are usually attributed to changes in nitrogen inputs, due to changes in land use or in nitrogen deposition whereas seasonal patterns are explained in terms of availability of soil nitrate for(More)
Using groundwater age determination through CFC analysis and geochemical data from 7 sites in Brittany (France) a hydro-geochemical model for hard rock aquifers is presented. According to the geological structure 3 zones can be defined: the weathered layer, about 30m thick; the weathered-fissured layer (fractured rock with a high density of fissures induced(More)
Although nitrate export in agricultural catchments has been simulated using various types of models, the role of groundwater in nitrate dynamics has rarely been fully taken into account. We used groundwater dating methods (CFC analyses) to reconstruct the original nitrate concentrations in the groundwater recharge in Brittany (Western France) from 1950 to(More)
A 7-year monitoring period of rare earth element (REE) concentrations and REE pattern shapes was carried out in well water samples from a 450 m long transect set up in the Kervidy/Coët-Dan experimental catchment, France. The new dataset confirms systematic, topography-related REE signatures and REE concentrations variability but challenges the validity of a(More)
In recent decades, temporal variations in nitrate fluxes and concentrations in temperate rivers have resulted from the interaction of anthropogenic and climatic factors. The effect of climatic drivers remains unclear, while the relative importance of the drivers seems to be highly site dependent. This paper focuses on 2-6 year variations called meso-scale(More)
Donnan Dialysis of Ag(+) and Zn(2+) was investigated through a cation exchange membrane (CMS Neosepta) when a proton concentration difference was maintained between the two sides of the membrane. Developed for the production of brine from sea water, CMS Neosepta showed a higher permeability to monovalent than to bivalent cations. Several physico-chemical(More)
We investigated the temporal and vertical changes in the microbial communities related to hydrological variations an aquifer (Brittany, France). Five water samplings were carried out, spanning three hydrological cycles in the variably and the permanently saturated zones. Seasonal variations in the major anion concentrations (NO3 -, SO4 2- and Cl(-) )(More)
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