Natural baseline quality within the Lower Triassic Sandstone of Lorraine (France): Status and evolution

The Triassic sandstones, that form an important aquifer on the Eastern border of the Paris Basin (France), have been intensively exploited by large scale pumping begun in the seventies that created a significant decrease in head level. Investigations using a combination of geochemical and isotopic methods have been carried out in 1979 and interpreted in terms of residence time of groundwater. This area appeared then of a special interest regarding the groundwater baseline evolution related to overexploitation and matches the objectives of the EU BaScLiNc project EVK1-1999- 00024 as it allows to establish long term trends in water quality of a deep groundwater system. A new field campaign (major, minor, trace elements and isotopes) was started in 2001 in order to highlight the modifications of the water quality in relation with the modifications of the piezometric levels and the circulation flow paths that occurred after the large scale pumping. (author)