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The present study aimed to identify the formation factors of the current hydrogeochemical character of the Middle-Jurassic aquifer groundwaters (beds YU 2-4) in the Lyaminsky petroleum district of West Siberia in Russia. We hypothesized that the scales of the impact of post-sedimentation processes at the current stage have largely predetermined the character of the Middle-Jurassic aquifer system. To check if the hypothesis is valid, two research problems have been addressed using the lithogenesis theory of the transformation of the groundwater composition during the geologic evolution: we have evaluated factors that governed the genetic type and composition of initial waters (lithologic, paleogeographic), and factors that control subsequent changes in the chemical composition of groundwaters (geotemperatures, neotectonics effect, etc.). To solve the first problem, the formation conditions of groundwaters under study in the continental setting were investigated. To settle the second problem, we obtained the coefficients of correlation between the Middle-Jurassic aquifer groundwater salinity and the current temperature and paleotemperature of the Tyumenian suite, and between the porosity coefficient and the basement depth. We have concluded that the current hydrogeochemical character of the Middle-Jurassic aquifer system is the resultant of the consecutive effects of the whole set of factors.

The paper presents the results of physicochemical analyses of spring waters in the Postomia River valley (Northwest Poland). Multivariate statistical methods, i.e., cluster analysis (CA) and principal component analysis (PCA) were used to assess the spatial distribution of similarities and differences in the concentrations of individual elements. Concentrations of macro elements (MEs), trace elements (TEs) and rare-earth elements (REEs) were analysed concerning the spring’s typology, land use structure and the distance from roads. The results showed that the springs waters are of the Ca2+-HCO3− and Ca2+-HCO3−-SO42− types, medium hardness and low mineralisation. The study revealed differences between valley springs and scarp-foot springs in terms of electrical conductivity and concentrations of F−, SO42−, NO3−, Mg2+, Ba, Zn, and U. Greater variability was observed between the physical and chemical conditions of the spring waters due to their location in terms of land use. Springs located in agricultural areas had lower pH values than those in other areas, and higher NO3− concentrations. The pH values and concentrations of Fe, Mo, Rb, and Th in urban areas were higher than in agricultural areas. Moreover, the concentrations of F−, Cl−, K+, Na+, Mo, Sb, Se, and Sr were higher in urban areas than in forested areas. The study shows that only HCO3− values and SO42− concentrations were related to the distance from the road network. The concentrations of Cl−, SO42−, and K+ were higher in the waters of springs located more than 50 m from the road network. The Ca and PCA analysis did not permit the identification of a single dominant origin of pollutants, suggesting an interaction of different types of pollution sources.