1. An evaluation of marine sediments in terms of their usability in the brick industry : case study Port of KoperPatrik Baksa, Franka Cepak, Rebeka Kovačič Lukman, Vilma Ducman, 2018, izvirni znanstveni članek Povzetek: A dredging process is essential for the development of harbours and ports, allowing the functional daily operation of the port. The management of dredged material represents a worldwide challenge, especially considering unwanted deposition of material. Because of their chemical, petrographic, mineralogical and homogeneity composition, marine sediments could represent an appropriate raw material for the brick industry, particularly for the production of clay blocks, roofing and ceramic tiles. In this study dredged material from Port of Koper was tested for such use, thus various analyses were carried out in order to determine if the dredged material is environmentally friendly and suitable for use in the brick industry. These included: chemical analysis, mineralogical analysis, particle size analysis, chloride content analysis and tests of firing in a gradient furnace. Furthermore, tests of mechanical properties, as well as tests of the frost-resistance of the samples were carried out. On the basis of the primary analyses and samples prepared in a laboratory, it was confirmed that marine sediments from the Port of Koper, without any additives are only conditionally suitable as a source material for producing brick products, because without additives they exhibit too much shrinkage on drying and firing, as well as high water absorption, this can be improved by the incorporation of suitable additives, for example, virgin clay or other suitable waste material. The approach described herewith can also be followed to assess sediments from other ports and rivers regarding its potential use in clay brick sector. Ključne besede: dredge marine sediment, recycling, clay bricks, mechanical properties, chemical analysis Objavljeno v DiRROS: 14.08.2024; Ogledov: 48; Prenosov: 26
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2. Benthic sediment as stores and sources of bacteria and viruses in streams : a comparison of baseflow vs. stormflow longitudinal transport and residence timesJennifer D Drummond, José Gonçalves, Tomás Aquino, Susan A. Bernal, Esperança Gacia, Ion Gutiérrez-Aguirre, Valentina Turk, Maja Ravnikar, Stefan Krause, Eugenia Martí Roca, 2023, izvirni znanstveni članek Povzetek: The presence of bacteria and viruses in freshwater represents a global health risk. The substantial spatial and temporal variability of microbes leads to difficulties in quantifying the risks associated with their presence in freshwater. Fine particles, including bacteria and viruses are transported and accumulated into shallow streambed (i.e., benthic) sediment, delaying the downstream transmission during baseflow conditions but contributing to their resuspension and transport downstream during stormflow events. Direct measurements of pathogen accumulation in benthic sediments are rare. Until now, the dynamic role of benthic sediment as both a store and source of microbes, has not been quantified. In this study, we analyze microbial abundance in benthic sediment along a 1 km reach of an intermittent Mediterranean stream receiving inputs from the effluent of a wastewater treatment plant, a known point source of microbes in streams. We sampled benthic sediment during a summer drought when the wastewater effluent constituted 100 % of the stream flow, and thus, large accumulation and persistence of pathogens along the streambed was expected. We measured the abundance of total bacteria, Escherichia coli (as a fecal indicator), and presence of enteric rotavirus (RoV) and norovirus (NoV). The abundance of E. coli, based on qPCR detection, was high (4.99∙102 gc /cm2) along the first 100 m downstream of the wastewater effluent input and in general decreased with distance from the source, with presence of RoV and NoV along the study reach. A particle tracking model was applied, that uses stream water velocity as an input, and accounts for microbial exchange into, immobilization, degradation, and resuspension out of benthic sediment during baseflow and stormflow. Rates of exchange into benthic sediment were 3 orders of magnitude higher during stormflow, but residence times were proportionately lower, resulting in increased longitudinal connectivity from up to downstream during stormflow. Model simulations demonstrated mechanistically how the rates of exchange into and out of the benthic sediment resulted in benthic sediment to act as a store during baseflow and a source during stormflow. Ključne besede: E. coli, norovirus, rotavirus, benthic sediment, pathogen transport, microbial risk Objavljeno v DiRROS: 12.07.2024; Ogledov: 143; Prenosov: 127
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3. Holocene climate variability in Slovenia : a reviewMatej Lipar, Sonja Lojen, Mateja Breg Valjavec, Maja Andrič, Andrej Šmuc, Tom Levanič, Jure Tičar, Matija Zorn, Mateja Ferk, 2024, pregledni znanstveni članek Ključne besede: palaeoclimate, climate proxy, glaciers, pollen, tree-rings, sediment, speleothems, historical data Objavljeno v DiRROS: 21.06.2024; Ogledov: 213; Prenosov: 145
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4. Overview of the thermal properties of rocks and sediments in SloveniaDušan Rajver, Simona Adrinek, 2023, pregledni znanstveni članek Povzetek: The use of geothermal energy, which comes from both deep geothermal systems and the shallow underground, has been developing rapidly in the last few decades. The purpose of the paper is to present the results of measurements of the thermal properties of all rock samples and sediments that were available from boreholes, two tunnels and numerous surface locations in Slovenia in the period from 1982 to the end of 2022. In relation to the shallow geothermal potential, a special effort is needed to characterize the thermal properties of the rocks and sediments and to implement thermal energy transfer technology. In this sense, knowledge of the thermal conductivity of rocks and sediments is required to assess the possibility of low-enthalpy heat exchange in a given local area. The largest number of measurements was taken to determine thermal conductivity. Determinations of thermal diffusivity were carried out on a much smaller number of rock and sediment samples, as well as determinations of radiogenic heat production in rocks. The results of thermal conductivity measurements on 430 samples from 119 wells, 20 samples from two tunnels and 156 samples from surface locations are shown. The highest thermal conductivities are shown by samples of dolomite, quartz conglomerate and conglomerate, phyllonite, quartz phyllite and gneiss, while the lowest are measured in sediments such as clay, lignite with clay, peat and dry sand. The determined radioactive heat generation is the lowest for milonitized dolomite and highest for dark grey sandstone with shale clasts. Our results are comparable to those already published worldwide, and they could be the basis for the possible future Slovenian standard for the thermal properties of measured rocks and sediments. Ključne besede: thermal conductivity, thermal diffusivity, borehole, tunnel, surface, rock, sediment, radioactive heat generation, Slovenia Objavljeno v DiRROS: 15.01.2024; Ogledov: 364; Prenosov: 189
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5. Evaluation of sediments from the river Drava and their potential for further use in the building sectorVilma Ducman, Karmen Fifer Bizjak, Barbara Likar, Mitja Kolar, Ana Robba, Jernej Imperl, Mojca Božič, Boštjan Gregorc, 2022, izvirni znanstveni članek Povzetek: Sedimentation is a naturally occurring process of allowing particles in water bodies to settle out of the suspension under a gravity effect. In this study, the sediments of the Drava River were fully investigated to determine the heavy metal concentrations along the river and their potential reuse in the construction sector. Naturally dehydrated sediments from the Drava River were tested as an additive for the production of fired bricks. The dredged sediments were used as a substitute for natural brick clay in amounts up to 50% by weight, and it was confirmed that up to 20% by weight of the added sediment could be used directly in the process without critically affecting performance. Finally, the naturally dehydrated sediments were also evaluated for their use as a filling material in the construction of levees. The natural moisture content of the dehydrated sediment was too high for it to be used without additives, so quicklime was added as an inorganic binder. The test results showed an improvement in the geotechnical properties of the material to such an extent that it is suitable as a filling material for levees. Ključne besede: sediment, pollution, clay industry, soil stabilization, open access Objavljeno v DiRROS: 31.05.2023; Ogledov: 517; Prenosov: 266
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6. Composite landslide in the dynamic alpine conditions: a case study of Urbas landslideEla Šegina, Mateja Jemec Auflič, Matija Zupan, Jernej Jež, Tina Peternel, 2022, izvirni znanstveni članek Povzetek: The alpine environment is characterized by complex geology, high-energy terrain, deeply incised river valleys with high erosional potential, extreme weather conditions and dynamic geomorphic processes. Such settings provide favourable conditions for the formation of composite landslides rather than individual slope mass movement phenomena. As an example, we present the kinematics of the composite landslide Urbas in the North of Slovenia which developed in the complex geological and morphological settings characteristic of the alpine environment. The research combines several monitoring techniques and involves the integration of both surface and subsurface displacements measured in the landslide area. The results indicate that the composite sliding process consists of several simultaneous and interrelated types of movements occurring in different segments of the unstable mass that are governed by different mechanisms of displacements, such as rockfall, sliding and debris flow. The kinematic characteristics of a deep-seated landslide that formed in such conditions vary spatially, but is rather homogenuous vertically, indicating translational type of movement. Spatial kinematic heterogeneity is primarily related to the diverse terrain topography, reflecting in different displacement trends. Based on the revealed kinematic proprieties of the sliding material, the sediment discharge illustrates the sliding material balance which estimates the volume of the retaining material that represents the potential for slope mass movement events of larger scales. Ključne besede: composite landslide, alpine conditions, kinematics, monitoring, sediment discharge Objavljeno v DiRROS: 15.12.2022; Ogledov: 814; Prenosov: 244
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7. Evaluation of thermal conductivity estimation models with laboratory-measured thermal conductivities of sedimentsSimona Adrinek, Rao Martand Singh, Mitja Janža, Mateusz Żeruń, Grzegorz Ryżyński, 2022, izvirni znanstveni članek Povzetek: Thermal conductivity is one of the key parameters for estimating low-temperature geothermal potential. In addition to field techniques, it can be determined based on physical parameters of the sediment measured in the laboratory. Following the methodology for cohesive and non-cohesive sample preparation, laboratory measurements were carried out on 30 samples of sediments. Density, porosity and water content of samples were measured and used in thermal conductivity estimation models (TCEM). The bulk thermal conductivity (λb) calculated with six TCEMs was compared with the measured λb to evaluate the predictive capacity of the analytical methods used. The results show that the empirical TCEMs are suitable to predict the λb of the analysed sediment types, with the standard deviation of the residuals (RMSE) ranging from 0.11 to 0.35 Wm−1 K−1. To improve the fit, this study provides a new modified parameterisation of two empirical TCEMs (Kersten and Côté&Konrad model) and, therefore, suggests the most suitable TCEMs for specific sample conditions. The RMSE ranges from 0.11 to 0.29 Wm−1 K−1. Mixing TCEM showed an RMSE of up to 2.00 Wm−1 K−1, meaning they are not suitable for predicting sediment λb. The study provides an insight into the analytical determination of thermal conductivity based on the physical properties of sediments. The results can help to estimate the low-temperature geothermal potential more quickly and easily and promote the sustainable use of this renewable energy source, which has applications in environmental and engineering science. Ključne besede: thermal conductivity, non-cohesive sediment, cohesive sediment, estimation model Objavljeno v DiRROS: 25.08.2022; Ogledov: 771; Prenosov: 350
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8. The environmental impact of historical Pb-Zn mining waste deposits in SloveniaMiloš Miler, Špela Bavec, Mateja Gosar, 2022, izvirni znanstveni članek Povzetek: Mining waste deposits (MWDs) represent significant and constant pollution source for the environment worldwide, thus it is very important to identify and diminish their environmental impacts. The aim of this study was to determine long-term environmental impacts and their temporal variations of MWDs in Pb–Zn mining districts in Slovenia and assess stability of potentially harmful element (PHE)-bearing phases in stream water. The results showed that investigated MWDs are important source of PHEs in stream sediments and that PHEs mostly occur as fine-grained and liberated PHE-bearing ore minerals. MWDs have generally stronger impact on sediments of smaller streams draining MWDs and main streams close to their confluences, however, fine-grained PHE-bearing material is transported along major watercourses over long distances causing regional pollution. Main ore minerals are mostly soluble in stream water. However, measured PHE leaching potential of MWDs is negligible. PHE levels in stream waters are thus low, demonstrating that drainage of MWDs predominantly contributes to PHE pollution in solid particulate form. Possible long-term remediation solution that would reduce environmental impact is recovery of metals from fine grain size fractions of MWDs, which could become an effective practice in sustainable management of historical MWDs. However, further studies of MWDs’ secondary resource potential, processing technology and evaluation of environmental aspects of extraction are needed. Ključne besede: metals, stream sediment, stream water, characterisation, mineral solubility Objavljeno v DiRROS: 03.03.2022; Ogledov: 829; Prenosov: 577
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