Depth–Sequential Investigation of Major Ions, δ18O, δ2H and δ13C in Fractured Aquifers of the St. Lawrence Lowlands (Quebec, Canada) Using Passive Samplers

General and isotopic geochemistry of groundwater is an essential tool to decipher hydrogeological contexts flow paths. Different hydrogeochemical patterns may result from the inherent physical aquifer heterogeneity, which go unnoticed without detailed investigations gathered multilevel or multiple observation wells. An alternative overcome frequent unavailability wellbores at sites perform a investigation on single wellbore available. In this perspective, aim study use passive samplers sequentially collect depths in long–screened wellbores. Such carried out for major ions stable isotopes compositions (δ2H, δ18O, δ13C) ten context fractured carbonate aquifers St. Lawrence Lowlands (Quebec, Canada). The information calco–carbonic system, report poorly stratified evolved bodies. Contribution water impacted by anthropogenic activities, such as road salts pollution carbon sources C4 vegetation, when they occur, are even observed greatest depths. observations suggest quick paths efficient mixing conditions, leads significant contributions contemporary bodies investigated down about 100 m. Although reported few heterogeneously distributed fractures per wellbore, findings point overall well interconnected fracture networks high vulnerability groundwater,