Search Results (87)

This study assessed the feasibility of cultivating Lavandula dentata in Technosols produced from fine and coarse coal mining waste, focusing on plant development, substrate functionality, essential oil production, and post-mining ecosystem restoration. The Technosols were formulated using coal waste from the Moatize Coal Mine, Mozambique, combined or not in different configurations with agricultural soil and amended with sewage sludge (3% organic matter) and chemical fertilizer to ensure adequate nutrient availability. The experiments were conducted in 30 L containers, performed in triplicate for each experimental group. All settings allowed good plant growth, although the treatment that used only fine waste presented the closest performance to agricultural soil in terms of the production of aerial biomass. In this case, the dried biomass production of the shoots reached an average of 165 g per pot over 8 months (with a standard deviation of 20.3). The study showed a positive correlation between plant development and the available water capacity of the substrates. The plant tissue of L. dentata, in all the Technosols configurations studied, presented a similar composition to the control, with a biomass composition within the standard range established by the literature. The essential oil production ranged from 0.3 to 0.7% (m/m), averaging 0.5% (m/m), with chemical characteristics also alike the control trial. Technosols composed of coal waste from Moatize appear to be an alternative, both to provide a suitable destination for mining waste and to provide conditions for the revegetation and recovery of degraded areas by coal mining. This avoids the commissioning of nearby areas to supply soil for the restoration process. L. dentata, in addition to its various medical, ornamental, and aromatic uses, has potential as an “ecological trigger” in the restoration process with environmental and socioeconomic benefits. Full article

Technosols are artificial soils produced from organic and inorganic solid waste to improve soil fertility and functionality. This study evaluated the potential of Technosols produced from household waste from the Altos de Guadalupe residential complex in Colombia to fertilize green areas and promote the growth of Duranta erecta. A physical characterization of waste from 46 houses was performed to estimate per capita production (PPC) and waste composition. Technosols were produced in 20, 50, and 200 L bioreactors using recyclable organic and inorganic waste arranged in 10 layers and composted for three months. A field trial was established with two treatments, soil without Technosols (T1) and soil with Technosols (T2), with three replicates and ten plants per plot (60 plants total). Soil fertility parameters and plant growth variables were evaluated over 300 days. The PPC reached 0.56 kg·capita⁻¹·day⁻¹, and 56.4% of the residues were suitable for Technosol production. Technosol exhibited a pH of approximately 7.1, an organic matter content of 11.1%, and phosphorus and potassium concentrations of 50.3 mg·kg⁻¹ and 2573 mg·kg⁻¹, respectively. Technosol increased soil organic matter by 5.4 percentage points and improved nutrient availability. After 300 days, plant height and root dry matter in T2 were 30% and 41% higher, respectively, than in T1 (p < 0.05). These results show that the use of Technosols on a residential scale can improve urban soil fertility and plant productivity, contributing to the principles of the circular economy and Sustainable Development Goals 11 and 12. Full article

The development of urban green infrastructures (UGI) is considered among the main nature-based solutions for climate mitigation in cities; however, the role of soils in the carbon (C) balance of UGI ecosystems remains largely overlooked. Urban green spaces are typically dominated by constructed Technosols, created by adding organic materials on top of former natural or agricultural subsoils. The combined effects of land-use history and current UGI management result in a high spatial variation of soil organic carbon (SOC) stocks and soil CO₂ emissions. Our study aimed to explore this variation for the case of Wageningen University campus. Developed on a former agricultural land, the campus area includes green spaces dominated by trees, shrubs, lawns, and herbs, with well-documented management practices for each vegetation type. Across the campus area (~32 ha), a random stratified topsoil sampling (n = 90) was conducted to map the spatial variation of topsoil (0–10 cm) SOC stocks. At the key sites (n = 8), representing different vegetation types and time of development (old, intermediate, and recent), SOC profile distribution was analyzed including SOC fractionation in surface and subsequent horizons, as well as the dynamics in soil CO₂ emissions, temperature, and moisture. Topsoil SOC contents on campus ranged from 1.1 to 5.5% (95% confidence interval). On average, SOC stocks under trees and shrubs were 10–15% higher than those under lawns and herbs. The highest CO₂ emissions were observed from soil under lawns and coincided with a high proportion of labile SOC fraction. Temporal dynamics in soil CO₂ emissions were mainly driven by soil temperature, with the strongest relation (R² = 0.71–0.88) observed for lawns. Extrapolating this relationship to the calendar year and across the campus area using high-resolution remote sensing data on surface temperatures resulted in a map of the CO₂ emissions/SOC stocks ratio, used as a spatial proxy for C turnover. Areas dominated by recent and intermediate lawns emerged as hotspots of rapid C turnover, highlighting important differences in the role of various UGI types in the C balance of urban green spaces. Full article

Heavy metal pollution in forest and agroforestry soils represents a persistent environmental challenge with direct implications for ecosystem functioning, food security, and human health. In tropical and subtropical regions, intense weathering, rapid organic matter turnover, and dynamic redox conditions strongly modulate metal mobility, bioavailability, and long-term soil vulnerability. This review synthesizes current knowledge on the sources, biogeochemical mechanisms, ecological impacts, monitoring approaches, and restoration strategies associated with heavy metal contamination in forest and agroforestry systems, with particular emphasis on tropical landscapes. We examine natural and anthropogenic metal inputs, highlighting how atmospheric deposition, legacy contamination, land-use practices, and soil management interact with mineralogy, organic matter, and hydrology to control metal fate. Key processes governing metal behavior include sorption and complexation, Fe–Mn redox cycling, pH-dependent solubility, microbial mediation, and rhizosphere dynamics. The ecological consequences of contamination are discussed in terms of soil health degradation, plant physiological stress, disruption of ecosystem services, and risks of metal transfer to food chains in managed systems. The review also evaluates integrated monitoring frameworks that combine field-based soil analyses, biomonitoring, and geospatial technologies, while acknowledging methodological limitations and scale-dependent uncertainties. Finally, restoration and remediation strategies—ranging from phytotechnologies and soil amendments to engineered Technosols—are assessed in relation to their effectiveness, scalability, and relevance for long-term functional recovery. By linking mechanistic understanding with management and policy considerations, this review provides a process-oriented framework to support sustainable management and restoration of contaminated forest and agroforestry soils in tropical and subtropical regions. Full article

Post-industrial heaps are a major environmental problem. They require remediation and reclamation, in which natural succession plays a key role in ecosystem development. This study aimed to assess the effect of heaps formed from materials of different origins on the nutrient content of silver birch (Betula pendula Roth), a pioneer species in this process. We analyzed nutrient contents in biomass fractions (fine and coarse roots, stemwood, bark, coarse and fine branches, leaves) and in soils sampled from 0 to 10, 10 to 20, 20 to 40, and 40 to 80 cm. Basic soil properties and the contents of N, P, K, Ca, Mg, S, Fe, Mn, Cu, and Zn in both soil and biomass were determined. The soils were poor in total organic carbon and differed in pH, texture, and nutrient status. Leaves and roots contained the highest nutrient contents, whereas stemwood contained the lowest. Statistical analyses revealed significant differences in all studied elements between heaps. Among macronutrients, N, P, and Mg were most abundant, followed by K, Ca, and S. Among micronutrients, Mn dominated, followed by Fe, Zn, and Cu. Findings underscore that silver birch growing on contaminated post-industrial heaps cannot be considered a hyperaccumulator of trace elements. Full article

Soil health is vital for the stability of agricultural production and ecosystem functions. However, the rapid urbanization process and environmental pollution have led to a sharp reduction in available arable land and accelerated soil degradation. Meanwhile, human activities generate a large amount of waste, which needs to be treated for resource recovery to reduce its potential pollution risks to the environment. By upcycling waste to mimic pedogenesis, Technosols offer a sustainable platform for land rehabilitation, environmental remediation, carbon sequestration and greenhouse gases emission reduction. However, the wide range of waste sources and complex compositions pose challenges to the standardized construction of Technosols suitable for agricultural production. This review systematically examines the sources and characteristics of waste, current utilization status and challenges in Technosol construction, and puts forward suggestions for developing agriculture-oriented Technosols through waste-novel nanomaterial composites. Finally, critical research directions are proposed regarding the relationship between Technosol fabrication and farmland environmental effects, including the targeted design, nanomaterial-enhanced construction, ecological impact assessment, and economic efficiency of agricultural Technosols. Full article

The escalating demand for non-renewable resources is anticipated to intensify extractive activities, which are invariably associated with significant environmental externalities. The rehabilitation of mined landscapes, undertaken to mitigate ecological degradation and reinstate ecosystem functions and biodiversity, is frequently constrained by substantial financial requirements as well as intricate technical, logistical, and environmental challenges. As a consequence, a considerable proportion of extractive sites worldwide remain unreclaimed. There is a critical need for sustainable, cost-effective, and versatile restoration practices. This article presents a bibliographic review focusing on problems encountered in mine remediation and the role of technosols in addressing these issues. Mine restoration initiatives are confronted with a suite of interrelated challenges, including suboptimal soil physicochemical characteristics, hydrological instability, geomorphological hazards, and the exacerbating effects of extreme climatic events. Technosols, formulated from various waste materials, prove to be a versatile and cost-effective biotechnology that can significantly improve soil fertility, reduce erosion, enhance water retention, and restore biological activity. Their application, which can include mining waste and organic residues, substantially lowers costs estimated globally at EUR 829.711 billion for soil formation and contributes to a circular economy. Technosols represent a promising and efficient biotechnology for mine restoration. Their use facilitates the creation of stable, functional, and self-sustaining landscapes, enabling not only environmental recovery but also social and economic benefits through post-restoration land uses. Further research and knowledge transfer are vital for their broader and optimised implementation. Full article

Ore mining and smelting are often related to environmental pollution. This study provides information about the geochemical features of Technosols at historical mining and metallurgical sites in the Tatra Mountains, southern Poland, evaluating the contents of potentially toxic trace elements (PTTE) and their behaviours in soils, as well as the influence of soil properties on PTTE mobility. Thirteen soil profiles were studied in eight abandoned mining and smelting sites. PTTE concentrations, including rare earth elements (REE), were measured using ICP-MS and ICP-OES. Selected elements (Cu, Zn, Pb, Cd, As, Sb, Ba, Sr, Co, Ni, Mn and Cr) were fractionated using the modified European Community Bureau of Reference (BCR) four-step sequential extraction. Contamination of soils with PTTE was compared against Polish regulatory limits, which were exceeded for Cu, Zn, Pb, Mo, Hg, As, Co, Ni and Ba, with concentrations exceeding limits by 16, 18, 34 and 160 times for Cu, Hg, As and Ba, respectively, in some profiles. Based on geochemical features depending on parent material properties, the soils examined were divided into three groups. Group I Technosols (near-neutral soils developed from Fe/Mn-ore and carbonate-bearing mining waste) were particularly enriched in Co, Ni, Mn and REE. Group II Technosols (acidic soils developed from polymetallic ore-bearing aluminosilicate mining waste) contained elevated concentrations of Cu, Zn, Hg, As, Sb, Bi, Co, Ag, Ba, Sr, U and Th; they contained lower contents of REE than Group I Technosols. Group III Technosols (soils developed in smelting-affected areas and containing metallurgical waste) were rich in Cu, As, Sb, Ba, Hg, Co and Ag and contained the lowest REE contents among the studied soils. Sequential BCR extraction revealed that PTTE mobility varied strongly according to soil group, with higher mobility of Mn, Cu and Zn in acidic polymetallic ore-derived soils (Group II), while carbonate-rich soils (Group I) showed mainly immobile forms. Metallurgical slag-derived soils (Group III) exhibited complex PTTE behaviour controlled by organic matter and Fe/Mn oxides. Soil properties (pH, carbonates and TOC) seem to control PTTE mobility. Full article

Urban gardening plays diverse social, cultural and economic roles; its further development appears to be worthwhile, provided that soil contamination does not compromise ecosystem services. This study was conducted at a complex of urban gardens in Wroclaw (Poland) where topsoil screening indicated significant spatial differentiation of trace elements content, presumably related to the history of the site. Urbic Technosols cover the reclaimed section of the gardens, where industrial and urban waste materials, such as ash, slag, construction and demolition, and household waste, were used to fill former clay and sand mines. Although the topsoil layers, comprised of transported external soil, exhibited beneficial physicochemical properties and high fertility, they were seriously contaminated with trace elements (up to 1700, 920, 740, 5.1, 7.4, and 5.1 mg kg⁻¹ zinc, lead, copper, cadmium, mercury, and arsenic, respectively). The trace elements were likely transferred from technogenic materials used for mine infilling, which now underlie the thin humus layers of the garden soils. The results suggest that the quality of soils in urban gardens located at reclaimed post-mining sites, while seemingly beneficial for horticulture based on physicochemical soil properties and fertility indices, can be seriously and permanently compromised by soil contamination from inappropriate materials used for site reclamation, thereby affecting soil quality and posing potential health and ecological risks. Full article

Active and abandoned mining sites are significant sources of heavy metals and metalloid pollution, leading to serious environmental issues. This study assessed the environmental risks posed by potentially toxic elements (PTEs), specifically arsenic (As) and antimony (Sb), in the Technosols (mining residues) of the former Pejão coal mine complex in Northern Portugal, a site impacted by forest wildfires in October 2017 that triggered underground combustion within the waste heaps. Our methodology involved determining the “pseudo-total” concentrations of As and Sb in the collected heap samples using microwave digestion with aqua regia (ISO 12914), followed by analysis using hydride generation-atomic absorption spectroscopy (HG-AAS). The concentrations of As an Sb ranging from 31.0 to 68.6 mg kg⁻¹ and 4.8 to 8.3 mg kg⁻¹, respectively, were found to be above the European background values reported in project FOREGS (11.6 mg kg⁻¹ for As and 1.04 mg kg⁻¹ for Sb) and Portuguese Environment Agency (APA) reference values for agricultural soils (11 mg kg⁻¹ for As and 7.5 mg kg⁻¹ for Sb), indicating significant enrichment of these PTEs. Based on average I_geo values, As contamination overall was classified as “unpolluted to moderately polluted” while Sb contamination was classified as “moderately polluted” in the waste pile samples and “unpolluted to moderately polluted” in the downhill soil samples. However, total PTE content alone is insufficient for a comprehensive environmental risk assessment. Therefore, further studies on As and Sb fractionation and speciation were conducted using the Shiowatana sequential extraction procedure (SEP). The results showed that As and Sb levels in the more mobile fractions were not significant. This suggests that the enrichment in the burned (BCW) and unburned (UCW) coal waste areas of the mine is likely due to the stockpiling of lithic fragments, primarily coals hosting arsenian pyrites and stibnite which largely traps these elements within its crystalline structure. The observed enrichment in downhill soils (DS) is attributed to mechanical weathering, rock fragment erosion, and transport processes. Given the strong association of these elements with solid phases, the risk of leaching into surface waters and aquifers is considered low. This work underscores the importance of a holistic approach to environmental risk assessment at former mining sites, contributing to the development of sustainable remediation strategies for long-term environmental protection. Full article

To meet the requirements for the efficient utilization of bulk solid wastes, technosols were cultivated using solid wastes as raw materials and their aggregate stability, bacterial community, mineralization process, and biological toxicity were investigated. A proportional mixture of four types of solid wastes (fly ash, sludge, straw, and earthworm manure) resulted in the formation of aggregates with excellent pore structure after two months of cultivation and four samples were obtained. Their soil organic matter (SOM) and total nitrogen (TN) contents were higher than those in Chinese surface soil. A total of 215 genera were common to all four samples. The high organic matter content in straw, along with its lignin content and the fine organic particles generated during the straw degradation process were conducive to the formation of highly stable aggregates, making the quality with added straw superior to that with added vermicompost. Furthermore, the addition of straw was more beneficial for increasing potential mineralized organic carbon. Amongst the four tested samples, sample 3# exhibited the best soil nutrient supply capacity along with strong mineralization but weak carbon sequestration. A seed germination test confirmed that four samples were all biologically safe. This study marked a shift from “pollution control” towards “resource utilization” in dealing with bulk solid wastes. Additionally, applying technosols for soil remediation could present an effective solution to ecological restoration challenges in soil degradation such as mining sites. Full article

The process of anthropogenic pedogenesis has necessarily become an important aspect of the study of today’s soils. The sustainable reclamation or remediation of soils degraded by industrial or mining activities is currently of great interest worldwide. In this field, the study of thin soil sections can provide relevant answers, particularly to questions concerning the evolution of these soils under the impact of reclamation practices. Here, we describe an experiment to reclaim former rare earth element mining sites in China using organic soil amendments and plantations of a local fiber plant, Boehmeria nivea. Two years after the start of the experiment, a study of soil structure, considered as an indicator of soil biofunctioning, was carried out on the different plots, supplemented by monitoring of physico-chemical properties. Morphological (light microscopy) and analytical (SEM-EDX, µ-XRF) characterization of thin sections allowed us to pinpoint some pedological processes as aggregation with particular reference to the contribution of biological factors and mineral species, highlighting the impact of the practices implemented. Using a soil micromorphology approach enabled us to track the rapid evolution of the early stages of pedogenesis of these Technosols and to provide insight into the potential for reclamation of these mined sites in the future. Full article

The effects of climate change are particularly pronounced in cities, where urban green infrastructure—such as trees, parks, and green spaces—plays a vital role in both climate adaptation and mitigation. This study assesses the carbon sequestration potential of urban forests in Budapest, the capital city of Hungary, which lies at the intersection of the Great Hungarian Plain and the Buda Hills, and is traversed by the Danube River. The city is characterized by a temperate climate with hot summers and cold winters, and a diverse range of soil types, including shallow Leptosols and Cambisols in the limestone and dolomite hills of Buda, well-developed Luvisols and Regosols in the valleys, Fluvisols and Arenosols in the flood-affected areas of Pest, and Technosols found on both sides of the city. The assessment utilizes data from the National Forestry Database and the Copernicus Land Monitoring Service High Resolution Layer Tree Cover Density. The results show that Budapest’s urban forests and trees contribute an estimated annual carbon offset of −41,338 tCO₂, approximately 1% of the city’s total emissions. The urban forests on the Buda and Pest sides of the city exhibit notable differences in carbon sequestration and storage, age class structure, tree species composition, and naturalness. On the Buda side, older semi-natural forests dominated by native species primarily act as in situ carbon reservoirs, with limited additional sequestration capacity due to their older age, slower growth, and longer rotation periods. In contrast, the Pest-side forests, which are primarily extensively managed introduced forests and tree plantations, contain a higher proportion of non-native species such as black locust (Robinia pseudoacacia) and hybrid poplars (Populus × euramericana). Despite harsher climatic conditions, Pest-side forests perform better in carbon sink capacity compared to those on the Buda side, as they are younger, with lower carbon stocks but higher sequestration rates. Our findings provide valuable insights for the development of climate-resilient urban forestry and planning strategies, emphasizing the importance of enhancing the long-term carbon sequestration potential of urban forests. Full article

Infiltration swales are a prospective key component of water-sensitive urban planning. The utilization of appropriate soil amendments is intended to facilitate the retention of pollutants from the stormwater runoff of traffic areas. Little is known about the possibility of utilizing processed construction and demolition waste (CDW) as an amendment to improve pollutant retention. We conducted batch and field tests to investigate (i) the leaching of metals and other elements from soil substrates containing CDW and (ii) their retention potential for copper (Cu) and zinc (Zn) when charged with real traffic area runoff. To gain a comprehensive understanding of the chemical interactions, we (iii) employed sequential extractions using an optimized protocol from treated and untreated soil substrates. In batch tests, the potential of vanadium leaching from technosols amended with brick-dominated CDW was apparent. When charged with traffic area runoff, the retentions of Cu and Zn in the technosols were comparable to those of the control soil without CDW. However, the simulation of high rainfall intensities reduced Cu and Zn retention in the technosols and the control. The results from the subsequent sequential extraction of Cu and Zn imply shifts in the chemical binding in the technosols compared to the control. Full article

The European Union prioritizes nature restoration, particularly in semiarid Mediterranean regions where integrating degraded coal mining areas into the landscape is essential. This involves maximizing water use and controlling runoff. A rehabilitation project in a former mining quarry was conducted with the objective of constructing suitable Technosols to support vegetation, limit erosion, and reduce rehabilitation costs. To prepare the substrate, mine spoils (saline materials) were mixed with residual materials, including discarded lignite powder, sewage sludge, pig slurry, and straw. Pig slurry was also introduced as a mulch in the experiment. A complete randomized block design with three replicates was set up, with each block containing two plots of the prepared substrate. In one of the plots, pig slurry was applied on the surface as a mulch to enhance infiltration and promote plant establishment. The quality of the newly created Technosols and the benefits of mulch application were evaluated 2 and 4 years after the rehabilitation. After two years, salt-tolerant plant species colonized the rehabilitated areas, providing sufficient vegetation cover to control water, soil, and nutrient losses, keeping soil losses below a 2.2 Mg ha⁻¹ yr⁻¹ threshold. Four years later, the new Technosols showed a fourfold increase in soluble organic-C content (up to 0.59 g kg⁻¹) and higher soil respiration rates compared to the mine spoils and lignite powder in the surrounding degraded quarry areas. No significant differences were observed in any parameters due to superficial slurry application. Addressing salinity and optimizing vegetation cover are crucial for the successful formation and sustainability of Technosols in these environments. Full article