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Waste Foundry Sand (WFS) is a byproduct from metal casting processes, often contaminated with heavy metals, acids, and carbon residues. As disposal costs rise, there is growing interest in repurposing WFS as an alternative to traditional aggregates in construction materials such as bricks, tiles, and concrete. However, concerns about the potential leaching of harmful chemicals into soil and groundwater pose significant barriers to its widespread use. By reducing the chemical pollutants, WFS becomes a competitive option for sustainable construction materials. This study aims to address these concerns by developing methods to extract WFS from the production cycle before it exceeds regulatory limits, thereby enhancing its suitability for recycling and reducing disposal costs. We assessed waste foundry sand (WFS) samples from various production cycles, following permissible guidelines, by mixing them with cement in proportions of 1%, 3%, and 5%. Our evaluation focused on their effectiveness as construction materials. The results indicated that the sample with 1% cement slightly exceeded the permissible limits for polycyclic aromatic hydrocarbons (PAHs), whereas the samples with 3% and 5% cement content complied with all regulatory standards. These findings suggest that WFS, particularly when combined with higher cement contents, holds promise as a sustainable construction material. This method not only reduces the need for extensive treatment and reclamation processes but also presents a cost-effective and environmentally friendly approach to managing WFS.

The agricultural production of maize (Zea mays L.) increases the risk of water erosion. Perennial crops like cup plant (Silphium perfoliatum L.) offer a sustainable alternative to produce biomass for biogas plants. The assessment of soil conservation measures requires calibrated soil erosion models that spatially identify soil erosion processes. These support decision-making by farmers and policymakers. Input parameters for the physically based soil erosion model EROSION 3D for cup plant cultivation were established in a field study. Rainfall simulation experiments were conducted to determine the model input parameter’s skinfactor and surface roughness. The results showed a reduction of soil erosion and higher infiltration rates for cup plant resulting in higher skinfactors of 11.5 in June and 0.75 post-harvest (cup plant) compared to 1.2 in June and 0.21 post-harvest (maize). With the extended parameter catalogue of EROSION 3D for cup plant cultivation model simulations were conducted for a rainfall event in June (64 mm). The sediment budget would have been reduced by 92.6% through the growth of cup plant in comparison to conventionally grown maize. Perennial cup plant can, therefore, contribute to achieving the targets outlined in the European Green Deal by reducing soil erosion and enhancing soil health.

Abstract Floodplain soilscapes act as temporary sinks in the environment and are nowadays affected by multiple contaminant accumulations and exposures, including different trace metals and plastics. Despite increasing knowledge about the occurrence and behaviour of plastics at the interface between aquatic and terrestrial systems, there are still major uncertainties about the spatial distribution of plastics, their sources and deposition, as well as spatial relationships with other contaminants. Our recent case study addresses these questions, using the example of a river system ranging from rural to urban areas. Based on a geospatial sampling approach we obtained data about soil properties, metal contents via ICP-MS analyses, and particle-based (171 μm – 52 mm) plastic contents, analysed using sodium chloride density separation, visual fluorescence identification and ATR-FTIR analysis. We found plastic contents of 0.00–35.82 p kg− 1 and zero to moderate metal enrichments. Levels of both contaminations occur in the lower range of known concentrations in floodplain soils and show a different spatial distribution along the river course and in the floodplain cross-section. Furthermore, we found that plastic enrichment occurs in the uppermost soil layers, while trace metal enrichment is equally distributed over depth, indicating different sources like flood dynamics and agricultural practice during different deposition periods. Finally, direct short to long-term anthropogenic impacts, like floodplain restoration or tillage may affect plastic enrichments, raising questions for future research directions within floodplain soilscapes.

Abstract The African continent is rarely the focus of microplastics research, although the ubiquity of microplastics in the environment is undisputed and still increasing. Due to the high production and use of plastic products and the partial lack of recycling systems in many parts of the African continent, it can be assumed that microplastic particles are already present in limnic and terrestrial ecosystems. Few studies, mainly from South Africa and the Northern African region, show a contamination with microplastics, especially in marine environments. This study aims to explore the presence and composition of microplastics in fluvial sediments of the major catchments in Namibia with a regional focus on the Iishana system in Northern Namibia, as one of the most densely populated areas in the country. In March 2019 and March 2021, at the end of the rainy seasons, sediments from the Iishana system and of the largest river catchments were sampled. Extraction was performed by density separation using the Microplastic Sediment Separator (MPSS) with the separation solution sodium chloride (density of 1.20 g/cm3). The particle size was determined by filtration and fractionation, and the polymer type by measurement with ATR-FTIR spectroscopy (minimum particle size 0.3 mm). Microplastics were found in the sediments of each river system, most of the particles in the Iishana system (average of 13.2 particles/kg dry weight). The perennial, the ephemeral rivers, and the Iishana system are similar concerning polymer type and particle size. Polyethylene and polypropylene were the dominant polymer types. Most of the particles were found in the size fractions 0.3 – 0.5 mm and 0.5 – 1.0 mm. The particles were found mainly as fragments and films, the majority transparent and brown.

Abstract Plastic contamination of terrestrial ecosystems and arable soils pose potentially negative impacts on several soil functions. Whereas substantial plastic contamination is now traceable in agro-landscapes, often internal-caused by the application of fertilizers such as sewage sludge, questions remain unanswered concerning what happens to the plastic after incorporation. Based on a combined surface and depth sampling approach, including density separation, fluorescence staining and ATR-FTIR or µFTIR analyses, we quantified macro- and microplastic abundance on two agricultural fields—34 years after the last sewage sludge application. By sub-dividing the study area around sludge application sites, we were able to determine spatial distribution and spreading of plastics. Past sewage sludge application led to a still high density of macroplastics (637.12 items per hectare) on agricultural soil surfaces. Microplastic concentration, measured down to 90 cm depth, ranged from 0.00 to 56.18 particles per kg of dry soil weight. Maximum microplastic concentrations were found in regularly ploughed topsoils. After 34 years without sewage sludge application, macro- and microplastic loads were significantly higher on former application areas, compared to surrounding areas without history of direct sewage application. We found that anthropogenic ploughing was mainly responsible for plastic spread, as opposed to natural transport processes like erosion. Furthermore, small-scale lateral to vertical heterogeneous distribution of macro- and microplastics highlights the need to determine appropriate sampling strategies and the modelling of macro- and microplastic transport in soils.

Heavy metals are known to be among one of the major environmental pollutants, especially in urban areas, and, as generally known, can pose environmental risks and direct risks to humans. This study deals with the spatial distribution of heavy metals in different pavement joints in the inner city area of Marburg (Hesse, Germany). Pavement joints, defined as the joint between paving stones and filled with different materials, have so far hardly been considered as anthropogenic materials and potential pollution sources in urban areas. Nevertheless, they have an important role as possible sites of infiltration for surface run-off accumulation areas and are therefore a key feature of urban water regimes. In order to investigate the spatial variability in heavy metals in pavement joints, a geospatial sampling approach was carried out on six inner city sampling sites, followed by heavy metal analyses via inductively coupled plasma–mass spectrometry (ICP–MS) and additional pH and organic matter analyses. A first risk assessment of heavy metal pollution from pavement joints was performed. Pavement joints examined consist mainly of basaltic gravel, sands, organic material and anthropogenic artefacts (e.g. glass and plastics), with an average joint size of 0.89 cm and a vertical depth of 2–10 cm. In general, the pavement joint material shows high organic matter loads (average 11.0 % by mass) and neutral to alkaline pH values. Besides high Al and Fe content, the heavy metals Cr, Ni, Cd and Pb are mainly responsible for the contamination of pavement joints. The identified spatial pattern of maximum heavy metal loads in pavement joints could not be attributed solely to traffic emissions, as commonly reported for urban areas. Higher concentrations were detected at run-off accumulation areas (e.g. drainage gutters) and at the lowest sampling points with high drainage accumulation tendencies. Additional Spearman correlation analyses show a clear positive correlation between the run-off accumulation value and calculated exposure factor (ExF; Spearman correlation coefficients (rSP) – 0.80; p<0.00). Further correlation analyses revealed different accumulation and mobility tendencies of heavy metals in pavement joints. Based on sorption processes with humic substances and an overall alkaline pH milieu, especially Cu, Cd and Pb showed a low potential mobility and strong adsorption tendency, which could lead to an accumulation and fixation of heavy metals in pavement joints. The presence of heavy metals in pavement joints poses a direct risk for urban environments and may also affect environments out of urban areas if drainage transports accumulated heavy metals. Finally, we encourage further research to give more attention to this special field of urban anthropogenic materials and potential risks for urban environments. Overall urban geochemical background values, and the consideration of run-off-related transport processes on pavements, are needed to develop effective management strategies of urban pavement soil pollution.

Headwater springs in the German Low Mountain Ranges are local ecotone habitats and biogeographical islands embedded in and interlinked with their adjacent landscape. The structure of forests reflects the eco-hydrological conditions in substrate type occurrence, microhabitat richness and biodiversity in forest springs. This study considers effects from different forest land cover by comparing spring habitats in deciduous beech forests and coniferous spruce forests on eco-hydrological structures and biodiversity. Study areas include six different forest landscapes in the Low Mountain Ranges in Central Germany in Hesse and Thuringia. Hydro-morphological structure mapping and invertebrate sampling was executed within a multi-habitat sampling regime, which involves sampling plots being allocated according to the cover ratio of the occurring substrata. Aquatic and terrestrial spring zones are considered with respect to an ecotone approach. Some in situ measurements were implemented, such as pH values, to assess the acidity of the spring water. Results show obvious differences in acidity, substrate type cover ratios and biodiversity in deciduous and coniferous forest springs. Conifer forest springs were found tending to acidification while deciduous forest springs were slightly alkaline. Deciduous forest springs had higher cover ratios of organic microhabitats as well as a higher biodiversity in species richness and total number of individuals. Although it was not possible to clearly distinguish one direct key factor of fauna assemblages, negative effects from forest management practices (e.g. monoculture plantations of conifer forest) on spring habitats can be concluded.

We examine the feasibility and added value of upscaling point data of soil moisture from a small- to a mesoscale catchment for the purpose of single-event flood prediction. We test the hypothesis that in a given catchment, the present soil moisture status is a key factor governing peak discharge, flow volume and flood duration. Multiple regression analyses of rainfall, pre-event discharge, single point soil moisture profiles from representative locations and peak discharge, discharge duration, discharge volume are discussed. The soil moisture profiles are selected along a convergent slope connected to the groundwater in flood plain within the small-scale catchment Husten (2.6 km²), which is a headwater catchment of the larger Hüppcherhammer catchment (47.2 km², Germany). Results show that the number of explanatory variables in the regression models is higher in summer (up to 8 variables) than in winter (up to 3 variables) and higher in the meso-scale catchment than in the small-scale catchment (up to 2 variables). Soil moisture data from selected key locations in the small catchment improves the quality of regression models established for the meso-scale catchment. For the different target variables peak discharge, discharge duration and discharge volume the adding of the soil moisture from the flood plain and the lower slope as explanatory variable improves the quality of the regression model by 15%, 20% and 10%, respectively, especially during the summer season. In the winter season the improvement is smaller (up to 6%) and the regression models mainly include rainfall characteristics as explanatory variables. The appearance of the soil moisture variables in the stepwise regression indicates their varying importance, depending on which characteristics of the discharge are focused on. Thus, we conclude that point data for soil moisture in functional landscape elements describe the catchments’ initial conditions very well and may yield valuable information for flood prediction and warning systems.

Periglacial cover beds are an important trigger of slope-water paths in sloped terrain of the mid-latitudes. Most hydropedological studies focus on the quantitative analysis about the interrelation between subsurface layering and runoff processes at the slope scale. In this research we emphasis on a qualitative environmental geochemical analysis of trace elements and dissolved organic carbon in a small forest hydrological study area in the central parts of the subdued mountains of Germany (Location: KrofdorferForst, +50° 41' 3.69", +8° 38' 38.87"). The main objective is to assess the effect of lithological discontinuities of stratified soils within the depth functions of trace elements concentration in soil solutions (soil water and its dissolved and mobile fraction in a vertical distribution). Lorz (2008) show that depth functions of manganese (Mn) are characterized by strong pedogenic dynamics, analysing a shortened sequential extraction of solid soil material. We investigated the hypothesis that lithological discontinuities act like aquicludes. Therefore we expect abrupt changes within the depth function of manganese as a result of such water-blocking effect (= geochemical barriers) as a consequence of mobilization under wet soil conditions. In a preliminary case study we sampled soil solutions from three different plots within a 400m-toposequence. We use in situ trench installed suction lysimeters with ceramic tips (Irrometer Soil Solution Access Tube) to extract soil water samples each 20 cm from top- (10 cm) to subsoil (110 cm). For geochemical element analysis we use an inductively coupled plasma mass spectrometry (ICP-MS). The results: A clear character of abrupt changes within the depth function could be illustrated for most of the plots. For example, at the upper slope plot a contrast of the depth function is from 1013 ppb mean concentration at 50 cm profile depth to 290 ppb mean concentration at 70 cm profile depth (17 month sampling period). To conclude, these results demonstrate that hydrochemical quality and translocation processes of soil solutions determining an interrelation between subsurface layering and run off processes - respectively could be seen as an environmental consequence of it.

Here for the first time, we analyze the concentration of dissolved (DOC) and particulate organic carbon (POC), as well as its optical properties (absorbance and fluorescence) from several proglacial streams across Iceland, the location of Europe’s largest non-polar ice cap. We found high spatial variability of DOC concentrations and dissolved organic matter (DOM) composition during peak melt, sampling 13 proglacial streams draining the 5 main Icelandic glaciers. Although glacial-derived organic matter (OM) was dominated by proteinaceous florescence, organic matter composition was variable among glaciers, often exhibiting relatively higher aromatic content and increased humification (based on absorbance and fluorescence measurements) closer to the glacier terminus, modulated by the presence of glacial lakes. Additional sampling locations the in flow path of the river Hvitá revealed that while POC concentrations decreased downstream, DOC concentrations and the autochthonous fraction of OM increased, suggesting the reworking of the organic carbon by microbial communities, with likely implications for downstream ecosystems as glaciers continue to melt. Based on our measured DOC concentrations ranging from 0.11 mg·L−1 to 0.94 mg·L−1, we estimate a potential annual carbon release of 0.008 ± 0.002 Tg·C·yr−1 from Icelandic glaciers. This non-conservative first estimate serves to highlight the potentially significant contribution of Icelandic pro-glacial streams to the global carbon cycle and the need for the quantification and determination of the spatio-temporal variation of DOC and POC fluxes and their respective drivers, particularly in light of increased rates of melting due to recent trends in climatic warming.

Springs are crucial interfaces within the Earth’s Critical Zone, connecting water and its related matter and energy at different scales from the microscopic to the macroscopic level. This connectivity is of importance for habitat conditions and the invertebrate community in springs as ecotones at the groundwater–surface water and the aquatic–terrestrial interfaces in headwater regions. Here, an integrative approach regarding an appropriate theoretical framework is given as an opinion on coupling perspectives from Ecohydrology and Earth Science. A theoretical integration within the approaches of the concepts of Earth’s Critical Zone and Hydropedology with its hierarchical framework is considered for bridging multiple scales from the individual substrate type to the entire spring habitat and the headwater catchment. The paper is in every respect an opinion on theoretical approaches and provides a synthesis within a conceptual framework for spring habitats, which should give further insight into how to study such small water bodies in the context of its adjacent landscape settings.

Despite their relatively large size, Icelandic glaciers, and their organic carbon (OC) fluxes, have not been explicitly considered in current global glacial OC flux calculations. Most global glacial OC estimates are based on limited individual flux estimates, often determined during the melt season, rarely accounting for the seasonal and diurnal variability of glacial dissolved organic matter (DOM). Using an annual dataset of 25 Icelandic glaciers (and their glacial streams) we investigate DOM concentration and composition, calculating an estimate for downstream OC fluxes from Icelandic glaciers, considering diurnal and seasonal variability. DOM source and composition distinctly changed from a terrestrial character toward a more proteinaceous character as melt increased, both on a seasonal and diurnal basis, likely reflecting the flow path of the meltwater. While DOC concentration did not change on a diurnal basis, DOM composition was more labile in the afternoons, possibly indicating photochemical or biological transformation processes. Overall, the glacial streams predominantly acted as CO 2 sinks. However, higher DOC concentrations, along with contributions of more proteinaceous DOM in proglacial streams, led to a decrease in the uptake potential for CO 2 . Finally, we estimated an export flux of 0.0026 ± 0.0029 Gg C yr -1  km -2 of DOC, and 0.011 ± 0.007 Tg C yr -1  km -2 of POC, from Icelandic glaciers. We reveal larger than previously assumed DOC and POC fluxes from Icelandic glaciers, with higher-than-global-average areal fluxes (~3 % and 9 % of global glacial C flux respectively). Our findings underscore the importance of revising current global estimates to include the not-fully-accounted-for contribution of Icelandic, and other glaciers. This is particularly important considering ongoing climatic changes will likely affect glacial meltwater discharge and sources, leading to altered DOM composition and DOC concentration, having potentially considerable consequences for glacial OC export and CO 2 uptake potentials of glacial streams., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Rainfall simulators are widely employed in soil erosion studies, and it is common for these simulators to be customized to address specific research questions. Nevertheless, there are certain characteristics that rainfall simulators should fulfill in the context of soil erosion studies. Rainfall simulators should simulate natural precipitation as accurately as possible. It is essential to monitor the size spectrum of generated raindrops, their maximum or terminal velocity, the uniformity of the surface distribution of rain, the kinetic energy and the overall intensity of the rain. This review aims to outline the characteristics and the corresponding measurement methods for rainfall simulators in soil erosion research. Electronic instruments like distrometers are considered more suitable for precise and comprehensive measurements than traditional instroments or literature based derivatives. By adhering to these characteristics, researchers can ensure the reliability and accuracy of their findings. Consequently, this overview serves as a valuable resource for researchers seeking to employ rainfall simulators in their investigations of soil erosion., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Author(s).)