NATURAL BASELINE QUALITY WITHIN THELOWER TRIASSIC SANDSTONE OF LORRAINE(FRANCE): STATUS AND EVOLUTION

摘要

The Triassic sandstones, that form an important aquifer on the Eastern borderof the Paris Basin (France), have been intensively exploited by large scale pumpingbegun in the seventies that created a signifi cant decrease in head level. Investigationsusing a combination of geochemical and isotopic methods have been carried out in1979 and interpreted in terms of residence time of groundwater. This area appearedthen of a special interest regarding the groundwater baseline evolution related to over-exploitationand matches the objectives of the EU BaSeLiNe project EVK1-1999-00024 as it allows to establish long term trends in water quality of a deep groundwatersystem. A new fi eld campaign (major, minor, trace elements and isotopes) was startedin 2001 in order to highlight the modifi cations of the water quality in relation with themodifi cations of the piezometric levels and the circulation fl ow paths that occurred afterthe large scale pumping.