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Povzetek: The impact of oxic and thermal transient phases on corrosion of carbon steel in cementitious environment was studied through three in situ experiments (Tournemire URL, France). For two years, heated metallic samples (80 °C) were placed in direct or indirect contact with two different cementitious materials: a low-pH Bentonitic Cement Grout (BCG) and a Portland cement paste material (CEM I). Mineralogical and microstructural analyses were carried out in an attempt to identify the combined effects of pH, chemistry and microstructure properties associated with such specific cementitious media on steel corrosion mechanisms. Additionally, in situ Electrical Resistance (ER) corrosion sensors allowed to continuously monitor the corrosion rates corresponding to each of the three field experiments. Post-mortem characterisation indicated that metallic samples embedded in low-pH BCG were heavily damaged and exhibited high corrosion rate. Conversely, steel samples in contact with highly alkaline CEM I environment appeared to be much less impacted by corrosion processes and revealed extremely low corrosion rate values. A comparison between these field experiments observations and results previously obtained through complementary laboratory mock-up tests finally enabled the evaluation of the impact that variations in geometrical/design aspect existing between in situ and laboratory tests can induce on material degradation.
Ključne besede: bentonitic cement-based grout, deep geological disposal of nuclear waste, anoxic environment, electrical resistance corrosion sensors, groundwater, low-pH cement
Objavljeno v DiRROS: 27.01.2026; Ogledov: 183; Prenosov: 49
Celotno besedilo (1,84 MB)
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Povzetek: Identification of contamination sources is critical for effective remediation planning in contaminated aquifers. This study presents a simulation–optimisation framework that was developed to reconstruct the release history and identify the potential source location after tetrachloroethene (PCE) concentrations that exceeded regulatory limits were detected in production and monitoring wells at the Hrastje well field. The approach integrates a physically based groundwater flow and solute transport model with an evolutionary algorithm to estimate unknown source parameters. The method was tested under realistic field conditions, accounting for the complexity and uncertainty of the subsurface environment. In the optimisation procedure, parameter values converged towards optimal estimates, and the simulated PCE concentrations in monitored wells showed good agreement with the observed values. The delineated source location and the reconstructed temporal and spatial dynamics of PCE contamination in the aquifer provide essential guidance for decision makers in designing and prioritising remediation strategies. By narrowing the potential source area, more targeted and cost-effective field investigations can be planned. The developed model offers a practical tool for evaluating alternative remediation scenarios, supporting adaptive water resource management and safeguarding the drinking water supply.
Ključne besede: groundwater contamination, remediation planning, drinking water protection, well field management, modelling
Objavljeno v DiRROS: 09.01.2026; Ogledov: 468; Prenosov: 198
Celotno besedilo (7,72 MB)
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Povzetek: Microplastics pollution in groundwater remains significantly underreported within scientific literature. This paper presents a comprehensive protocol outlining the methodology for the sampling of groundwater from boreholes, as well as the steps of microplastics separation and analysis. It provides an extensive description of a filtration sampling system designed specifically for this purpose, along with the detailed sampling procedure. In addition, it presents the laboratory analysis of microplastic particles, including their characterization based on size, shape, color, transparency, and chemical structure using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and micro-FTIR spectroscopy. Factors that can influence results are discussed, and special attention is paid to preventing contamination of samples. The methodology described also considers the requirements of the Annex of Commission Delegated Decision (EU) 2024/1441 of 11 March 2024, supplementing Directive (EU) 2020/2184 of the European Parliament and of the Council. This comprehensive written protocol, accompanied by video guidance, is intended to support the development of a synchronized methodology for monitoring microplastics in groundwater or drinking water. This resource will be of interest to researchers in the field of microplastics worldwide.
Ključne besede: microplastics, groundwater, spectroscopic methods, pollution
Objavljeno v DiRROS: 26.11.2025; Ogledov: 703; Prenosov: 249
Celotno besedilo (1,09 MB)
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Povzetek: Alluvial aquifers serve as vital groundwater resources worldwide. Due to their complex heterogeneity, accurate characterization requires the integration of multiple data types. This study presents a systematic framework to address aquifer heterogeneity through hydrofacies analysis, combining borehole data, electrical resistivity tomography (ERT) and stochastic modeling. The approach was tested in the Varaždin aquifer, where geostatistical and stochastic tools were used to simulate the spatial distribution of four hydrofacies: gravel (G), gravel, sandy to clayey (Gsc), sand with gravel, clayey to silty (Sgcs), and clay to silt, sandy (CSs). As the thin and electrically conductive lenses of Sgcs-CSs material below 20 m depth limited the ERT resolution, synthetic models were used to infer their possible geometry and resistivity magnitudes, estimating a model of the hydrofacies distribution up to 35 m depth, consistent with field-data based model. The resulting dimensions of the lens-shaped structures revealed the horizontal extent of the hydrofacies, and were incorporated into horizontal Markov chain models. The 3D Markov chain models were used to generate 10 stochastic realizations of the hydrofacies distribution. Validation identified the representative hydrofacies model for the Varaždin aquifer with a prediction accuracy of 63 %. Results from simulations focused on the Vinokovščak wellfield area show that incorporating ERT-derived lens lengths into the model development slightly improved hydrofacies prediction accuracy by 0.3 % to 5.0 %, depending on hydrofacies model grid resolution. The analysis of different grid resolutions demonstrates that increasing model detail beyond the characteristic lens dimensions provided no accuracy improvement, suggesting that the optimal cell size is closely related to the estimated lens lengths. In contrast, coarser grids provide a simplified hydrofacies model, potentially increasing prediction accuracy but losing spatial resolution. This methodology forms a basis for integrating spatial heterogeneity into groundwater models, providing a useful tool for sustainable management in alluvial and similar sedimentary environments.
Ključne besede: alluvial sediments, aquifers, groundwater, water resources, hydro-facies, wells, geophysical investigations, modelling
Objavljeno v DiRROS: 22.10.2025; Ogledov: 391; Prenosov: 138
Celotno besedilo (8,08 MB)

Povzetek: Stable subsurface temperatures provide a reliable source of shallow geothermal energy. This research is one of a few that investigates the potential of closed-loop systems for cold storage facilities. We listed 47 cold storage facilities in Slovenia and evaluated the capacity of two 50 m deep borehole heat exchangers that would penetrate one of five intergranular aquifers. As the Slovenian legislation does not define temperature thresholds of the heat carrier fluid, we applied – 3 °C and +24 °C as conservative boundary conditions. First, we quantified the possible amount of injected waste heat with the analytical model (EED) using seven scenarios. Further, we upgraded our results with the three scenarios in the numerical model (FEFLOW), including groundwater flow. The calculation revealed that the optimal natural conditions for geothermal cooling of cold storages are in the Sava Basin, where fast groundwater flow (7.2 m/day) increases possible injected heat in numerical calculation to more than 900 % compared to analytical calculation. Cooling capacities decrease from the Sava to Drava, Mura, Savinja and Krško Basins. Our research quantitatively confirms that areas with groundwater flow are more conductive to restoring underground temperatures through the injection of waste heat from cooling cold storages than areas without groundwater flow.
Ključne besede: shallow geothermal energy, cold storage facility, intergranular aquifer, heat load, groundwater flow, Slovenia
Objavljeno v DiRROS: 28.08.2025; Ogledov: 621; Prenosov: 178
Celotno besedilo (14,49 MB)