The hummocky Balaton Highland is located in western Hungary and is part of the Transdanubian Mountains, the most extensive carbonate aquifer system in Hungary. The study region also encompasses Lake Balaton, the biggest lake in central Europe, which is to the south of Balaton Highland. The surface water–groundwater interaction in the Balaton Highland–Lake Balaton region and the groundwater contribution to Lake Balaton are revisited in this paper. Hydrostratigraphic classification was performed first; then, groundwater flow directions by hydraulic head distribution were analysed, and baseflow indices of surface watercourses were calculated. Regarding hydrochemical characterisation, general hydrochemical facies were identified, natural tracers of temperature, chloride and uranium were applied, and the stable isotopic composition of oxygen and hydrogen was determined. Finally, groundwater flow and heat transport were simulated in a 2D numerical model. A high level of hydraulic interaction was evidenced between surface water and groundwater and the sub-regions of Bakony Mountains, Balaton Highland and Lake Balaton by physical and chemical parameters, numerical simulation and groundwater-flow-related natural manifestations, revealing hydraulic continuity in the study region. Based on the results, the division of legislative water bodies can be reconsidered, especially that surface water and groundwater should be regarded as interconnected, and Lake Balaton can be considered a groundwater-dependent ecosystem in any water-use planning in the region.

The traditional study of palaeoseismic trenches, involving logging, stratigraphic and structural interpretation, can be time consuming and affected by biases and inaccuracies. To overcome these limitations, a new workflow is presented that integrates infrared hyperspectral and photogrammetric data to support field‐based palaeoseismic observations. As a case study, this method is applied on two palaeoseismic trenches excavated across a post‐glacial fault scarp in northern Finnish Lapland. The hyperspectral imagery (HSI) is geometrically and radiometrically corrected, processed using established image processing algorithms and machine learning approaches, and co‐registered to a structure‐from‐motion point cloud. HSI‐enhanced virtual outcrop models are a useful complement to palaeoseismic field studies as they not only provide an intuitive visualisation of the outcrop and a versatile data archive, but also enable an unbiased assessment of the mineralogical composition of lithologic units and a semi‐automatic delineation of contacts and deformational structures in a 3D virtual environment.

Lake Velence is a shallow soda lake whose water level and water quality show a severely deteriorating tendency in recent years. Until recently, the groundwater component in the lake’s water budget has not been taken into consideration. To integrate the lake into the groundwater flow system at the regional scale, methods of “basin hydraulics” were applied. In addition, 17 water samples were collected for δ²H and δ¹⁸O, and for ΣU, ²²⁶Ra and ²²²Rn activity measurements to use these parameters as environmental tracers of groundwater contribution. Groundwater mapping revealed that groundwater recharges in Velence Hills and the local elevations south of the lake, whereas discharge occurs by the lake’s shoreline and along surface watercourses. The results indicated that Lake Velence is the discharge point of local groundwater flow systems known to be more sensitive to climate changes and anthropogenic activities (e.g., contamination, overexploitation). Groundwater and lake water have similar uranium activity concentrations serving as another sign of groundwater inflow into the lake. Therefore, it is necessary to consider both the groundwater component in the lake’s water management and its vulnerability regarding local and short-term changes in the catchment area.

Groundwater quality constantly evolves through rock–water interactions, which can enrich groundwater with undesirable elements such as naturally occurring radionuclides. The aim of this study was to understand the cause of gross alpha activity exceeding the screening value of 0.1 Bq L⁻¹ measured in groundwater-derived drinking water in the vicinity of a metamorphic outcrop in Hungary. As groundwater quality is strongly dependent on the properties of groundwater flow systems, environmental tracers (δ²H and δ¹⁸O composition, ²²⁶Ra, ²²²Rn, total U activity concentration, and ²³⁴U/²³⁸U ratio) and hydraulic evaluation were applied to understand groundwater dynamics. The collected groundwater samples had total U activities up to 540 mBq L⁻¹, which translates into an indicative dose below the drinking water parametric value. However, in the presence of dissolved uranium, the δ²H (−52.6–(−83.4)) and δ¹⁸O (−7.17–(−11.96)) values led to the conclusion that local flow systems were sampled that are known to be most vulnerable to any changes in their recharge area. The results confirm that the groundwater flow system approach involving environmental tracers and hydraulic evaluation is a powerful tool for identifying the cause of natural radioactivity in groundwater-derived drinking water.

This study explores a sustainable approach for the recovery of metal values from copper slag using hydrogen (H₂). The high-temperature isothermal reduction experiments were carried out under a controlled H₂-Ar atmosphere and the subsequent molten slag extraction technique was employed. The elemental concentrations in both the metal/matte and the reduced slag were examined using inductively coupled plasma optical emission spectroscopy and electron probe microanalysis. It was found that the submerged H₂ blowing technique has a superior impact to top surface blowing on recovering metals from copper slag due to improved mass and heat transfer in the slag. Approximately 65 pct of copper of the initial 1.19 wt pct can be reduced into copper alloy after reduction by submerged H₂ blowing with the lowest concentration of 0.4 wt pct in slag. More than 90 pct of zinc and lead deported into the gas phase as metals. This research contributes to the ongoing efforts to enhance the sustainability of metallurgical processes and reduce their environmental footprint. Graphical Abstract

Understanding the role of major components of electric waste during smelting of these materials to recover valuable trace metals is poorly constrained by experimental data. In this study, phase equilibria and trace element deportments were studied at 1473 K (1200 °C) in conditions of combined sulfide concentrate and electric and electronic equipment waste processing in batchwise submerged lance smelting. In this system, liquid slag domain is limited by silica and magnetite saturation boundaries or primary phase fields at all alumina concentrations from alumina-free slags to silica-spinel double saturation. The impact of alumina concentration in slag at fixed oxygen and sulfur dioxide partial pressures on the distributions of Ag, Cu, In, Pb, and Sn was studied. Elemental concentrations in slag, matte, and solid magnetite (a Fe–Al spinel solid solution) were measured using electron probe microanalysis and laser ablation-ICP-mass spectrometry techniques. The observed impact of alumina on the distribution coefficient of silver, copper, and indium favored the matte phase at silica and magnetite saturation but lead and tin behaved differently within different primary phase fields as a function of alumina concentration.