Natural attenuation of pharmaceuticals and personal care products percolating through rocky substrates – an example based on the Káraný waterworks

This survey focused on a detailed analysis of the ability of fluvial Quaternary sediments to remove pharmaceuticals and personal care products (PPCPs) from drinking water. Thirty-eight PPCPs were detected in the Jizera River, which is used after infiltration to produce drinking water by the Káraný waterworks. Several PPCPs occurred in the water at concentrations exceeding 100 ng/l, some of which are not possible to remove (oxypurinol, acesulfame). The presence of PPCPs was monitored after infiltration and during passage through sandy gravels to the receiving well (total distance of 180 m) at monthly intervals in 2022–2023. PPCPs can be divided into different groups based on the results. Iohexol, iopromide, metoprolol, cetirizine, valsartan and clarithromycin were already below the established threshold after passing through 60 m of gravel. Other substances were gradually attenuated and a diverse group of PPCPs remained in the groundwater even after passing through 180 m of subsoil. Surprisingly, the PPCP with a high degree of attenuation, such as metformin, whose concentration drops from the original value of 677 ng/l to 16 ng/l, was in this group. The member of this group with lowest degree of attenuation was sulfamethoxazole with a value of 9%. Five substances (benzotriazole, propylparaben, bisphenol S, hydrochlorothiazide, ibuprofen-2-hydroxy) were identified as the most problematic since they passed through the quaternary fluvial aquifer practically unchanged and the process of qualitative treatment using artificial infiltration appears to be ineffective

Will the river Irtysh survive the year 2030? Impact of long-term unsuitable land use and water management of the upper stretch of the river catchment (North Kazakhstan)

International audienceThe Irtysh river basin all the way from river spring in China across Kazakhstan as far as the Russian part of Siberia is among the most ecologically endangered and affected regions on our planet. The study provides a summary of the historical reasons for anthropological interventions in this area, which began with the construction of plants of the military—industrial complexes in the forties of the last century during World War II. These plants have a major share in extreme high concentrations of heavy metals in surface as well in groundwaters locally. The Semipalatinsk nuclear polygon plays a specific role as a source of contamination of local waters. The release of top secret data enabled us to gain knowledge about serious problems related to high radioactivity of groundwaters, which should spread uncontrollably through a system of secondary fissures activated by nuclear blasts. Another serious problem in this region is the quantitative aspect of contamination. Model simulations of water balance indicate that large industrial development in the spring area in China and continuously increasing water consumption in Kazakhstan may lead to desiccation of the lower stretch of this large river in Siberia during the summer months of 203

Isotope hydrogeology and geothermal applications to clarify the origin, the sustainability and the character of groundwater flow (examples of the Bohemian and Aquitaine sedimentary basins)

Les études isotopiques couplées avec des informations géothermiques peuvent constituer des outils pertinents pour l exploration des eaux souterraines en tant que ressources en eau potable ou géothermiques. Ce travail combine les deux approches, isotopes de l environnement et radioactifs associés à des données de température sur des aquifères profonds, dans l objectif d enrichir et d améliorer la connaissance des mécanismes de recharge (Bassin d Aquitaine, France) ainsi que des mécanismes de recharge et du potentiel géothermique (Bassin Crétacé de Bohème, République Tchèque).Les isotopes stables (18O, 2H, 13C) utilisés conjointement avec des radioisotopes (14C, 3H) sont utilisés pour estimer l époque de la recharge ainsi que les conditions climatiques qui prévalaient lors de l infiltration depuis la fin de Pléistocène jusqu à nos jours. Définir le type de recharge et les conditions d écoulement est nécessaire pour parvenir à modéliser de façon satisfaisante et fiable les grands systèmes aquifères profonds. Trois types de recharge ont été définis en Europe - (i) continue, (ii) interrompue lors du dernier maximum glaciaire (LGM) un troisième type (iii) correspond à des situations particulières de recharge.Les conditions géographiques et climatiques très différentes rencontrées en France et en République Tchèque ont engendrées une importante hétérogénéité des conditions et processus de recharge. Le sud de la France, avec un climat relativement doux depuis les derniers 40 ka BP, n a pas enregistré d interruption de la recharge. Le temps de séjour des eaux souterraines en Bohème est estimé à environ 11 ka BP au maximum. Cependant, l appauvrissement des teneurs en isotopes stables enregistré suggère une recharge liée à la fonte de la calotte glaciaire Nord Européenne après le dernier maximum glaciaire (LGM), autour de 18-20 ka BP. Des investigations sur les isotopes du carbone minéral dissous des eaux souterraines du bassin de Bohème ont montrées d importantes interactions avec différentes sources de carbone qui ont été identifiées.Pour le site d étude tchèque, les informations apportées par la géochimie ont été complétées par des données géothermiques afin d améliorer la connaissance des flux et de la dynamique des eaux souterraines. Plus d une centaine d enregistrements diagraphiques de température ont été utilisés pour estimer le gradient géothermique. Plusieurs phénomènes viennent perturber le gradient géothermique de la région. Les flux d eau souterraine verticaux et les variations lithologiques et topographiques sont à l origine d une distribution complexe du flux de chaleur, étant majoritairement conditionné par les écoulements souterraines. Les discontinuités peu profondes et les nombreux pointements volcaniques exercent aussi une influence importante sur l écoulement souterrain et donc aussi sur le potentiel géothermique du réservoir. Les investigations sur la géothermie ont ainsi fourni des informations fondamentales sur le potentiel géothermique mais aussi sur les conditions d écoulement des eaux souterraines. La prise en compte de ces informations s avère nécessaire afin de proposer des modèles mathématiques d écoulement réalistes.Isotopic investigations combined with geothermal applications represent powerful tools for the exploration of groundwater potential as a drinking or geothermal resource. This Ph.D. thesis combines both approaches, environmental and radioactive isotopes together with temperature data in deep aquifers, in order to enrich and update the knowledge concerning the aquifer recharge processes in the Aquitaine Basin (France) and the aquifer recharge processes and geothermal potential in the Bohemian Cretaceous Basin (Czech Republic).Stable isotopes (18O, 2H, 13C) combined with radioisotope data (14C, 3H) are used to estimate the recharge timing and climatic conditions prevailing during the infiltration from the Late Pleistocene up to modern time. The character of groundwater recharge and regime are necessary to generate relevant source data for the accurate modelling of complex groundwater systems. Three groups of groundwater recharge types can be distinguished throughout Europe (i) continuous recharge and (ii) interrupted recharge during Last Glacial Maximum and (iii) a group corresponding to particular recharge conditions.The contrasted geographic and climate conditions at both study sites in France and Czech Republic have entailed a great heterogeneity of the recharge conditions and processes. Southern France, with generally mild climatic conditions during the last 40 ka BP, did not experienced considerable hiatus in groundwater recharge. The residence time of groundwater in the Bohemian aquifers is estimated about 11 ka BP at the maximum but the depletion in the stable isotopes suggests that this groundwater originates in the melting of the north European ice sheets after the Last Glacial Maximum period, i.e. 18-20 ka BP. Further investigations on both stable and radioactive carbon isotopes indicated numerous groundwater interactions within the reservoir that were used to delineate the carbon origin within the Bohemian aquifers.Information on groundwater geochemistry was supplemented in the Czech case study by geothermal data in order to improve our knowledge of groundwater flow and dynamics. More than a hundred of temperature records from well-logging measurements were used to assess the geothermal gradient in the Bohemian Cretaceous Basin which is the most promising heat accumulation within the country. Many phenomena can affect the thermal field in the region. Vertical groundwater flow and variations in the lithology and the topography lead to a complicated areal distribution of the geothermal gradient and the heat flux which is dominantly controlled by groundwater. Shallow tectonic structures and numerous volcanic rocks exercise an influence on groundwater flow and therefore exert a secondary effect on the thermal field. The geothermal investigation provided useful information on the geothermal resources within the region but also represents an important tool for understanding groundwater flow, and for constructing realistic hydrogeological models in such a complex geological, tectonic and geothermal context.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF