Search Results (414)

Environmental risk assessment of landfill solid waste should include higher plants as indicators of toxicity to support sustainable waste management. This study evaluated solid waste from mining and power-generating industries using SANS 10234, a multidisciplinary approach that combined physicochemical analysis of waste samples and the Phytotoxkit bioassay to assess plant-based toxicity. Leachate extractions from samples identified as wastes of concern were evaluated using standard toxicity tests. Based on the Phytotoxkit results, Coal solid waste A, Clinker ash, and Chrome solid waste were identified as wastes of concern, whilst the whole effluent toxicity test results of the leachate indicated that these three samples pose a low risk to aquatic ecosystems. The phytotoxicity was attributed to the waste’s physicochemical parameters. Coal solid waste A expressed a low pH of 2.60 and a high electrical conductivity of 14,557 µS/cm, while Clinker ash presented a pH of 6.72 and an electrical conductivity value of 3685 µS/cm. These values were outside the optimal range for many plants to thrive. The presence of toxic elements in some samples may have contributed to the observed phytotoxicity. These results highlight that solid waste can present varying risks to both terrestrial and aquatic systems, reinforcing the importance of including higher plants in landfill risk assessments for sustainable waste management. Full article

Meeting European carbon neutrality and energy performance targets requires large-scale rehabilitation of historic and traditional buildings, one of the construction sector’s key challenges by 2050. This will significantly increase demand for new materials and the production of waste, which already accounts for 39% of waste in Wallonia. From a circular economy and urban mining perspective, however, this waste can be viewed as a valuable resource for reuse and recovery. Despite this potential, Wallonia lacks detailed information on the material composition of its historic building stock, including material types, quantities, and reuse potential. Such knowledge is crucial for designing effective renovation strategies and promoting circular construction practices. The URMIBALI project addresses this gap by investigating traditional residential buildings built before 1919 in Liège (Belgium). Based on six case studies, the project develops two complementary research parts. The first part focuses on inventorying existing material stocks, estimating waste flows resulting from energy renovations, and evaluating the reuse potential of the main waste fractions. The second part proposes an initial digital methodology for the rapid and efficient acquisition of façade material data. The project’s novelty lies in its multi-material, bottom-up, and transdisciplinary approach, as well as in the creation of previously unavailable data on building-stock composition and the development of simple and flexible digital methods to acquire those data. These outputs improve knowledge of traditional buildings, support projections of renovation waste up to 2050, and facilitate urban-scale management of material flows, including transport, supply chains, and environmental impacts. This contribution presents the research methodology, key findings, and the transferability of the digital method to other building typologies and European contexts. Full article

African soils face increasing levels of metal pollution due to industrialization, artisanal mining activities, improper waste management, and enhanced agricultural productivity. However, unlike many organic pollutants, heavy metals do not degrade naturally and therefore persist in environmental systems for prolonged periods. Heavy metals accumulate over many decades in the soil and bioaccumulate through the food chain causing severe health complications such as cancer, kidney problems, and neurological impairment. This paper reviews the current literature on the origin, prevalence, and behavior of the main pollutants Pb, Cd, Cr, As, Hg, and Cu. The major phytoremediation methods including phytoextraction, rhizofiltration, phytostabilization, and phytovolatilization are highlighted alongside in planta screening methods for hyperaccumulating plants including Berkheya coddii (Ni) and Haumaniastrum robertii (Co). The paper evaluates various enhancement techniques such as the use of chelators, Rhizobium inoculations, and genetic modifications. The significance of these approaches in tropical and subtropical climates is discussed. The paper suggests a holistic framework involving empirical kinetic modeling, geospatial machine learning (random forest, kriging), and molecular omics in prediction modeling. Major hurdles in such predictions include lack of field-based verification of the models, biotechnology safety of genetically modified (GM) organisms, and inadequate regulations. Future perspectives emphasize community-driven phytomining, biomass recycling, and resilient phytoremediation solutions. Full article

Although the green belt around Greater Lomé (GBGL) is a vital ecological buffer, it is currently facing significant degradation. This decline appears to be associated with a combination of various socioeconomic uses by the local community and formal operations of established businesses. Grounded in the cultural materialism framework, this study aims to contribute to a better understanding of the dynamics of the socioeconomic uses of the green belt around Greater Lomé in a context of degradation and investigates the dynamics of these socioeconomic uses and their environmental impacts through a multidisciplinary methodology. This approach combines anthropological analysis based on field observation, 53 semi-structured interviews and 5 focus groups, a quantitative questionnaire survey (n = 384) and an analysis of land use and land cover (LULC) dynamics derived from Landsat imagery (2003–2023). The results reveal six main types of socioeconomic uses of the GBGL (notably land transactions, agriculture, breeding and grazing, exploitation of wood energy, timber and utility wood, sand mining, and waste disposal), which lead to complex social dynamics ranging from conflicts to alliances among stakeholders. The LULC dynamics analysis indicates a staggering 468.26% expansion in built-up areas over the last 20 years, at the expense of swamp vegetation/gallery forest (−76.79%), tree-and-shrub savanna (−53.47%) and plantations (−49.43). This study provides a scientific basis supporting the urgent necessity to establish the GBGL as a legally protected entity and argues in favour of an inclusive management model that is designed to reconcile the socioeconomic survival needs of local populations with sustainable preservation of essential ecosystem services. Full article

To reduce the generation of waste electrical and electronic equipment (WEEE), or electronic waste (hereafter referred to as E-waste), within urban waste streams, extended producer responsibility (EPR) has evolved into an important framework for E-waste management and circular economy policies worldwide over the past thirty years. This policy has received increasing attention because of concerns regarding environmental pollution and resource depletion, as E-waste may contain heavy metals, such as mercury, cadmium, and lead, as well as valuable metals, including gold, silver, platinum, palladium, copper, and aluminum. In the developed East Asia region, Japan, South Korea (hereafter abbreviated as Korea), and Taiwan are renowned for their electronics industries and share similar socioeconomic and environmental characteristics, such as high population density, dependence on imported resources, and comparable levels of per capita national income. This review paper first provides the brief information on precious and valuable base metals derived from E-waste in urban waste. Furthermore, it presents a brief overview of the legal systems for urban waste management and compares urban mining from E-waste in Japan, Korea, and Taiwan. In this regard, the policies, regulations, and achievements related to urban waste management and E-waste recycling in East Asia, especially in Taiwan, are summarized and linked to increasing recycling rates for urban waste, including E-waste. Finally, the paper also examines two leading case studies in Taiwan, which focus on the recovery of precious metals from information and communication technology (ICT) products and valuable base metals from home electronic appliances, respectively. Full article

Using solid wastes to fabricate sustainable backfill materials for mining engineering is crucial for environmental sustainability worldwide. In this study, the use of coal gangue aggregates as a sustainable alternative to natural aggregates in geopolymer gel backfill materials was explored, which contributes to green mining development. Through uniaxial compression tests, the effects of fine gangue content, mass concentration, and the binder content of geopolymer backfill materials on the compressive behavior of coal gangue geopolymer gel backfill–rock combinations (CGBRC) were systematically evaluated. Digital Image Correlation (DIC) and acoustic emission (AE) techniques were employed to reveal the strain field evolution and damage progression of CGBRC. Results show that as the content of fine coal gangue increases, the compressive strength first increases and then decreases. Compared with the compressive strength at a 20% content, the compressive strength at a 40% content increased by 33.2%, while the elastic modulus increased by 11.2%. Meanwhile, with the increase in mass concentration and binder content, the compressive strength and elastic modulus of coal gangue geopolymer filling materials show an increasing trend, reaching peak values at 86% mass concentration and 32% binder content, respectively. The strain concentration zones mainly form near the backfill interface, with propagation paths governed by backfill strength. Damage evolution undergoes three stages including rapid accumulation during compaction, gradual development in the elastic-plastic stage, and abrupt acceleration at failure. The interfacial debonding behavior is primarily influenced by the strength difference between the backfill and surrounding rock. Specimen failure is dominated by brittle shear fracture, categorized into three modes based on crack paths relative to the backfill, which include penetrating backfill failure, axisymmetric interface failure, and centrally symmetric interface failure. These findings offer theoretical and technical support for coal gangue resource utilization and green mining practices, advancing sustainable solid waste management. Full article

Phosphate waste rock piles (PWRPs) generated by open-pit phosphate mining are highly heterogeneous and difficult to characterize using conventional point sampling alone, which limits representative resource assessment, selective recovery, and rehabilitation planning. This study develops an integrated framework combining PRISMA spaceborne hyperspectral imagery, ground-based mineralogical analyses, and spatially constrained machine learning to map lithological heterogeneity at the Benguerir phosphate mining site, Morocco. A three-stage spectral optimization workflow, including atmospheric band masking, Savitzky–Golay filtering, and analysis of variance (ANOVA)-based feature selection, was applied to identify the most discriminative Short-Wave Infrared (SWIR) bands for lithological classification. After removing redundant observations located within shared PRISMA pixel footprints, 127 spatially independent samples were retained for model development. Five supervised classifiers (Random Forest, Extra Trees, XGBoost, Support Vector Machine, and K-Nearest Neighbors) were evaluated under a spatially constrained cross-validation framework aligned with the 30 m native PRISMA pixel size. Ensemble-based models, especially Extra Trees and Random Forest, provided the most stable performance, with balanced accuracies of 0.56–0.69 and area under the receiver operating characteristic curve (AUC) values exceeding 0.95 for carbonate-dominated lithologies. Lower discrimination between phosphate and siliceous facies reflects intrinsic mineralogical mixing and spectral overlap at the sensor scale. Entropy-based uncertainty and posterior probability mapping revealed spatially structured prediction ambiguity concentrated along lithological boundaries and transitional zones, consistent with petrographic evidence of compositional heterogeneity. These results indicate that moderate but stable accuracies likely represent realistic performance limits for spaceborne hyperspectral mapping of complex mining environments under spatial constraints. The proposed framework provides a transferable and uncertainty-aware basis for lithological mapping, selective recovery assessment, and sustainable phosphate waste management. Full article

End-of-life tyres present a significant waste management challenge, prompting increasing interest in the use of tyre-derived materials in engineering applications. This review critically evaluates the performance of tyre-derived materials across concrete, asphalt, geotechnical, and mining systems with emphasis on application-specific engineering trade-offs. The reviewed literature shows that tyre-derived materials commonly reduce compressive strength and stiffness, particularly in cementitious systems, due to their weak interfacial bonding and increased porosity. However, these reductions are often accompanied by improvements in ductility, energy absorption, crack resistance, damping behaviour, tolerance during deformation, and post-cracking integrity. The magnitude of these responses strongly depends on rubber size, content, material origin, and interaction with the host matrix. Mining backfill applications show emerging potential, with tyre-derived inclusions improving brittle to ductile transition behaviour and residual integrity in cemented rock fill systems, although current evidence remains largely laboratory-based. Overall, the review demonstrates that tyre-derived materials should be evaluated according to application-specific performance requirements rather than strength-based criteria alone, while environmental benefits should be assessed on individual cases separately. Full article

Mining activities generate substantial volumes of solid waste materials during exploration and processing. These residuals pose environmental and geotechnical concerns due to their large spatial footprints and associated risks but may also contain potentially valuable resources. These characteristics highlight the necessity and opportunity of effective management and monitoring strategies. In recent years, a diverse range of technologies and methods have been applied to characterize mine waste compositions and analyze their spatial–temporal variability. These include remote sensing systems, ground-based sensors, and advanced data-driven methods. Despite the rapid advancement, the existing literature provides limited insight into the critical evaluation of how these techniques are applied in practice. This review systematically examines peer-reviewed journal articles published between 2021 and 2024 to highlight the state of the art in characterization, modeling, and monitoring techniques for mine waste. The review identifies recent trends, key gaps, advantages, and limitations of these techniques. The summary suggests that mining companies and research communities are increasingly adopting innovative technologies, transitioning from conventional methods to more sustainable practices. However, it also reveals ongoing challenges and persistent limitations. Further efforts, such as real-time monitoring capabilities, are required to achieve full implementation and integration across the industry and academia. Full article

Flotation tailings and metallurgical slags from mining often contain toxic Pb, Cd, and Zn. In this study, we evaluated the in situ immobilization of Pb, Cd, and Zn in a Pb–Zn flotation tailing and a smelting slag by adding representative amendments: phosphate-based (ammonium phosphate, phosphoric acid, glassy fertiliser), cementitious (Portland cement), and iron-based (bog iron ore) materials at 1–10% (w/w). Treated samples underwent EPA-TCLP and pH-dependent leaching tests (pH 3–10), with Pb, Cd, and Zn measured by atomic absorption spectroscopy. The untreated tailing leached hazardous Pb (~60 mg/L) and elevated levels of Cd (~0.7 mg/L) and Zn (~53 mg/L), whereas the untreated slag leached negligible metal concentrations. All amendments reduced metal release in a dose-dependent manner. Phosphate amendments were most effective (e.g., 10% H₃PO₄ cut tailing Pb by 80%, Cd by 60%, and Zn by 30%), while cement and iron additions had much weaker effects. Solid-phase XRD and SEM-EDS analyses indicated the formation of stable calcium–phosphate minerals on sulfide surfaces after phosphate treatment. These findings suggest that low-cost phosphate additives (~5–10%) can substantially immobilize Pb, Cd, and Zn in such wastes. However, under strongly acidic conditions (pH < 3), some remobilization occurred, highlighting the need for further validation. This work provides practical guidance for waste managers on selecting in situ stabilization strategies for Pb–Zn mine wastes. Full article

Landfilling remains the dominant waste disposal method worldwide, particularly in developing countries, posing serious environmental, health, and climate challenges. Inefficient practices, weak regulations, and un-engineered sites contribute to massive greenhouse gas (GHG) emissions and resource loss. Transitioning to a circular economy (CE) offers a transformative path for sustainable waste management. By closing material loops, recovering energy, urban mining, controlling emissions and CE strategies can convert traditional landfills into eco-efficient systems. The integration of artificial intelligence (AI) further enhances this transition, enabling real-time monitoring, predictive management, and optimized resource recovery, thereby maximizing environmental and economic benefits. This review presents a three-level CE framework at micro (individual organizations), meso (industrial networks), and macro (national and international) levels designed to extract maximum value from waste streams and mitigate climate impacts. The proposed strategies demonstrate the potential to drastically reduce GHG emissions, promote clean energy via waste-to-energy routes, and contribute to SDGs 7, 11, 12, 13 and 15. By combining technology, innovation, and strategic management, this work highlights how AI-driven CE approaches can transform landfills from environmental liabilities into engines of sustainability and climate action. In implementing CE strategies at various levels, various challenges including technological, socio-economic, ethical, policy-based, and unintended consequences are encountered which impact sustainability initiatives. This review comprehensively discusses challenges associated with CE implementation and identifies technological advancement, social awareness and data-driven AI/ML-based modeling which could ensure success in circularity and ultimately curb climate change impacts in the long term. Full article

The invasive plant Datura stramonium L. possesses strong reproductive capacity and ecological adaptability, showing a tendency to spread rapidly, especially in highly human-disturbed habitats. To explore its resource utilization pathway—turning waste into wealth—and to address toxic metal pollution in strongly human-disturbed areas (such as mining regions), this study evaluates its phytoremediation potential in contaminated soils on the Qinghai–Tibet Plateau. We established a non-planted control and three planting density treatments to compare the removal rates of Pb, Cd, Cr, and As. To our knowledge, this is the first study to assess how planting density influences the multi-metal phytoremediation performance of this invasive species in a high-altitude plateau environment. The results showed that planting significantly increased toxic metal removal rates, with overall efficiency generally improving at higher densities, particularly for Cr. Analysis of bioconcentration and translocation factors revealed distinct element-specific accumulation patterns. Pb and As were primarily enriched and retained in the roots. Interestingly, while Cd exhibited a strong localized tendency to accumulate in the leaves, its overall root-to-shoot translocation remained relatively restricted at the whole-plant level, similar to Cr. Overall, D. stramonium functions primarily through root stabilization for Pb, As, and Cr, alongside partial aboveground accumulation for Cd. However, given its toxic and invasive nature, any practical phytoremediation application requires strict post-harvest biomass management and ecological monitoring to prevent secondary spread. Full article

Transitioning to a circular economy (CE) is now a strategic priority for countries to decouple economic growth from environmental degradation. However, in developing contexts, the readiness of environmental resource sectors to adopt CE principles is unknown due to a lack of data and uneven institutional capacity. This study presents the first regional baseline assessment of circularity readiness in Vietnam’s environmental resource sectors, focusing on land, mining, water and waste. A five-dimensional readiness framework (policy, resource management, innovation, business, awareness) was developed and applied across Vietnam’s six ecological–economic regions. A Delphi process with 12 experts was conducted in three rounds to capture and refine expert judgments, supplemented by triangulated proxy indicators (e.g., plastic recycling rates, wastewater treatment coverage). Readiness scores were aggregated at dimension and regional levels and analyzed using radar charts, heatmaps and hierarchical clustering. Results showed significant regional disparities. The Southeast (SE) and Red River Delta (RRD) have high readiness due to clearer policy frameworks, stronger institutions and more dynamic business ecosystems. The Northern Midlands and Mountains (NMM) and Central Highlands (CH) have low readiness due to infrastructural gaps, weak innovation and limited public engagement. The Mekong Delta (MD) and North Central Coast (NCC) have medium readiness, reflecting partial progress but uneven implementation. The study made three contributions: (1) a new context-specific framework for CE readiness in environmental resource sectors; (2) the value of expert-based, proxy-informed methods in data-scarce contexts; and (3) a policy roadmap for different regional readiness levels. Findings suggest that the CE should be integrated into resource planning, regional observatories should be established and CE-related research and development (R&D) should receive investment. Future research should move towards standardized quantitative indicators and predictive models to track how readiness changes under policy interventions. Full article

Growing environmental pressures have increased interest in zero-waste practices within the hospitality industry, while digital platforms have become key spaces where such practices are interpreted and debated. However, limited research has examined how zero-waste hospitality is represented in digital public discourse. This study addresses this gap by analyzing 10,944 posts from X (Twitter) collected globally in English using an integrated approach combining text mining, sentiment analysis, and topic modeling implemented in Python (v3.14.5). The findings indicate that online discussions are predominantly neutral and positive, suggesting a normalization of zero-waste practices, while critical narratives point to concerns about greenwashing, pricing, and implementation consistency. Topic modeling further shows that zero-waste hotels are framed within broader themes, such as circular economy and carbon reduction, rather than solely operational practices. Building on these insights, the study proposes a three-layer conceptualization of digital sustainability discourse—informational, normative, and critical dimensions. By offering a conceptual perspective grounded in large-scale user-generated data, the study contributes to sustainable tourism literature and advances our understanding of how sustainability practices are socially constructed in digital contexts. Full article

Yacuri National Park (YNP) is a Ramsar site located within Ecuador’s Podocarpus-El Cóndor Biosphere Reserve. The Park faces critical threats from illegal mining, livestock grazing, wildfires and the harvesting of wax palms. This study employed participatory action research to co-design a Communication, Education and Public Engagement (CEPA) plan with park managers and local communities as equal partners. Moving beyond traditional, top-down information campaigns, the CEPA framework establishes a co-governance model that integrates indigenous knowledge with local socio-economic realities. The plan implements four targeted interventions: (1) strengthening community fire brigades (BRICOM); (2) promoting culturally appropriate alternatives to Holy Week wax palm harvesting; (3) establishing participatory waste management; and (4) engaging tourists as conservation allies through experiential learning. Strategic alliances with municipalities, universities, and civil society organizations provide institutional backing and secure resources, while a participatory monitoring system using SMART indicators tracks behavioral and ecological outcomes. Ultimately, the findings demonstrate that conserving culturally complex, biodiverse landscapes requires social legitimacy, environmental justice and equitable power-sharing. Recognizing local communities as co-managers is essential to ensuring the long-term protection of Andean ecosystems. Full article