Search Results (175)

Soil acidification, salinization, and heavy metal pollution pose serious threats to global food security and sustainable agricultural development. Biochar, with its high porosity, large surface area, and abundant functional groups, can effectively improve soil properties. However, due to variations in feedstocks and pyrolysis conditions, it may contain potentially harmful substances. Industrial wastes such as fly ash, steel slag, red mud, and phosphogypsum are rich in minerals and show potential for soil improvement, but direct application may pose environmental risks. The co-application of biochar with these wastes can produce composite amendments that enhance pH buffering capacity, nutrient availability, and pollutant immobilization. Therefore, a review of biochar-industrial waste composites as soil amendments is crucial for addressing soil degradation and promoting resource utilization of wastes. In this study, the literature was retrieved from Web of Science, Scopus, and Google Scholar using keywords including biochar, fly ash, steel slag, red mud, phosphogypsum, combined application, and soil amendment. A total of 144 articles from 2000 to 2025 were analyzed. This review summarizes the physicochemical properties of biochar and representative industrial wastes, including pH, electrical conductivity, surface area, and elemental composition. It examines their synergistic mechanisms in reducing heavy metal release through adsorption, complexation, and ion exchange. Furthermore, it evaluates the effects of these composites on soil health and crop productivity, showing improvements in soil structure, nutrient balance, enzyme activity, and metal immobilization. Finally, it identifies knowledge gaps as well as future prospects and recommends long-term field trials and digital agriculture technologies to support the sustainable application of these composites in soil management. Full article

Plant growth regulators (PGRs) enhance crop stress resistance but their roles in microbial-mediated phosphorus cycling within intercropping systems are unclear. Thus, We conducted a two-year field study using corn (Zea mays L. cv. Denghai 605) and soybean (Glycine max L. cv. Hedou 22) in fluvisols and luvisols soil according to World Reference Base for Soil Resources (WRB) standard. Under a 4-row corn and 6-row soybean strip intercropping system, three treatments were applied: a water control (CK), and two plant growth regulators—T1 (EC: ethephon [300 mg/L] + cycocel [2 g/L]) and T2 (ED: ethephon [300 mg/L] + 2-Diethyl aminoethyl hexanoate [10 mg/L]). Foliar applications were administered at the V7 stage (seventh leaf) of intercropped corn plants to assess how foliar-applied PGRs (T1/T2) modulated the soil phosphorus availability, microbial communities, and functional genes in maize intercropping systems. PGRs increased the soil organic phosphorus and available phosphorus contents, and alkaline phosphatase activity, but not total phosphorus. PGRs declined the α-diversity in fluvisols soil but increased the α-diversity in luvisols soil. The major taxa changed from Actinobacteria (CK) to Proteobacteria (T1) and Saccharibacteria (T2) in fluvisols soil, and from Actinobacteria/Gemmatimonadetes (CK) to Saccharibacteria (T1) and Acidobacteria (T2) in luvisols soil. Functional gene dynamics indicated soil-specific regulation, where fluvisols soil harbored more phoD (organic phosphorus mineralization) and relA (polyphosphate degradation) genes, whereas phnP gene dominated in luvisols soil. T1 stimulated organic phosphorus mineralization and inorganic phosphorus solubilization in fluvisols soil, upregulating regulation genes, and T2 enhanced polyphosphate synthesis and transport gene expression in luvisols soil. Proteobacteria, Nitrospirae, and Chloroflexi were positively correlated with organic phosphorus mineralization and polyphosphate cycling genes, whereas Bacteroidetes and Verrucomicrobia correlated with available potassium (AP), total phosphorus (TP), and alkaline phosphatase (ALP) activity. Thus, PGRs activated soil phosphorus by restructuring soil type-dependent microbial functional networks, connecting PGRs-induced shifts with microbial phosphorus cycling mechanisms. These findings facilitate the targeted use of PGRs to optimize microbial-driven phosphorus efficiency in strategies for sustainable phosphorus management in diverse agricultural soils. Full article

Artisanal and small-scale gold mining (ASGM) poses significant environmental challenges globally, particularly due to mercury (Hg) use. As an example, in Ecuador, Hg use still persists, despite its official ban in 2015. This study investigated the geogenic and anthropogenic contributions of potentially toxic elements (PTEs) in the Ponce Enriquez Mining District (PEMD), a region characterized by hydrothermally altered basaltic bedrock and Au-mineralized quartz veins. To assess local baseline values and identify PTE-bearing minerals, a comprehensive geochemical, mineralogical, and petrographic analysis was conducted on bedrock and mineralized veins. These findings reveal distinct origins for the studied PTEs, which include Hg, As, Cu, Ni, Cr, Co, Sb, Zn, and V. Specifically, Hg concentrations in stream sediments downstream (up to 50 ppm) far exceed natural bedrock levels (0.03–0.707 ppm), unequivocally indicating significant anthropogenic input from gold amalgamation. Furthermore, copper shows elevated concentration primarily linked to gold extraction. Conversely, other elements like As, Ni, Cr, Co, Sb, Zn, and V are primarily exhibited to be naturally abundant in basalts due to the presence of primary mafic minerals and to hydrothermal alterations, with elevated concentrations particularly seen in sulfides like pyrite and arsenopyrite. To distinguish natural geochemical anomalies from mining-related contamination, especially in volcanic terrains, this study utilizes Upper Continental Crust (UCC) normalization and local bedrock baselines. This multi-faceted approach effectively helped to differentiate basalt subgroups and assess natural concentrations, thereby avoiding misinterpretations of naturally elevated element concentrations as mining-related pollution. Crucially, this work establishes a robust local geochemical baseline for the PEMD area, providing a critical framework for accurate environmental risk assessments and sustainable mineral resource management, and informing national environmental quality standards and remediation efforts in Ecuador. It underscores the necessity of evaluating local geology, including inherent mineralization, when defining environmental baselines and understanding the fate of PTEs in mining-impacted environments. Full article

The poultry industry produces significant quantities of keratin-rich waste, primarily feathers, whose traditional disposal methods—incineration or chemical treatment—result in environmental damage and resource depletion. This research introduces a sustainable biotechnological method for the valorization of feather waste utilizing Gordonia alkanivorans S7, an actinomycete strain extracted from petroleum plant sludge. This is the inaugural publication illustrating keratinolytic activity in the Gordonia genus. The optimization of the degradation process via the Taguchi approach led to the effective biodegradation of untreated home chicken feathers, achieving dry mass loss of up to 99% after 168 h in a mineral medium. The agricultural potential of the obtained keratin hydrolysate, which was high in organic components (C 31.2%, N 8.9%, H 5.1%, and S 1.7%), was assessed. Phytotoxicity tests demonstrated that the feather hydrolysate led to better growth of the indicator plants—Sorghum saccharatum and Lepidium sativum. The highest values of root growth stimulation were 26% for S. saccharatum and 31% for L. sativum, at a dose of 0.01%. Shoot growth stimulation was noted only for L. sativum, reaching 38% (0.01%), 53% (0.05%), and 37% (0.1%), as compared to the control sample. These results demonstrate the process’s combined economic and environmental benefits, providing a fresh approach to the production of bio-based plant biostimulants and sustainable keratin waste management. Full article

To ensure the green, safe, and efficient extraction of mineral resources and promote sustainability, the stability of mined-out areas has become a critical factor affecting safe production and ecological restoration in underground metal mines. The instability of underground goafs poses a significant threat to mine safety, especially when irregular excavation patterns interact with high ground stress, exacerbating instability risks. Most existing studies lack a systematic and multidisciplinary integrated framework for comprehensive evaluation and management. This paper proposes a trinity research system of “assessment–optimization–governance”, integrating theoretical analysis, three-dimensional fluid–solid coupling numerical simulation, and a filling sequence optimization method based on genetic algorithms. An analysis of data measured from 243 pillars and 49 goafs indicates that approximately 20–30% of the pillars have a factor of safety (FoS) below 1.0, signaling immediate instability risks; additionally, 58% do not meet the threshold for long-term stability (FoS ≥ 1.5). Statistical and spatial analyses highlight that pillar width-to-height ratio (W/H) and cross-sectional area significantly influence stability; when W/H exceeds 1.5, FoS typically surpasses 2.0. Numerical simulations reveal pore water pressures of 1.4–1.8 MPa in deeper goafs, substantially reducing effective stress and accelerating plastic zone expansion. Stability classification categorizes the 49 goafs into 7 “poor”, 37 “moderate”, and 5 “good” zones. A genetic algorithm-optimized filling sequence prioritizes high-risk area remediation, reducing maximum principal stress by 60.96% and pore pressure by 28.6%. Cemented waste rock filling applied in high-risk areas, complemented by general waste rock filling in moderate-risk areas, significantly enhances overall stability. This integrated method provides a scientific foundation for stability assessment and dynamic remediation planning under complex hydrogeological conditions, offering a risk-informed and scenario-specific application of existing tools that improves engineering applicability. Full article

Sustainable mineral resource management is critical amid escalating environmental concerns and growing demand for minerals in digital and clean energy technologies. While financial technology (FinTech) has been widely recognized for enhancing financial inclusion and economic efficiency, its role in environmental governance—particularly in the mining sector—remains underexplored, especially within developed economies like the United States. This study addresses this gap by examining how FinTech adoption influences mineral sustainability, using time series data from 1998 to 2023. Four FinTech proxies—mobile cellular subscriptions, Internet usage, fixed broadband access, and financial inclusion—were analyzed alongside environmental compliance and investment in sustainable mining technologies. Using the Autoregressive Distributed Lag (ARDL) model and Frequency Domain Causality (FDC) analysis, the results show that greater FinTech adoption significantly reduces mineral depletion rates, indicating improved sustainability. Internet and broadband access exhibit strong long-term impacts, while mobile connectivity and credit access show notable short- and medium-term effects. Investment in sustainable mining technologies further enhances these outcomes. Our findings suggest that FinTech serves as a multidimensional enabler of sustainability through digital inclusion, transparency, and access to green financing. This study provides empirical evidence to guide policymakers in integrating digital financial infrastructure into strategies for sustainable mineral resource governance. Full article

Heavy metals in lead refining waste slag pose persistent environmental risks, challenging conventional treatment methods that struggle to balance long-term stabilization with resource recovery potential. To address this issue, we developed a sustainable stabilization strategy. The simultaneous and long-lasting stabilization of Zn, Pb, and As heavy metals in lead refining waste slag was achieved by using an Fe-S(II) stabilizer, and the leaching toxicity of Zn, As and Pb was less than 1 mg/L, which is lower than the concentration limit of the Identification standards for hazardous wastes–Identification for extraction toxicity (GB5085.3-2007). The samples were analyzed by characterization before and after stabilization, and it was found that Fe-S(II) formed a protective layer of sulfide capsule on the surface of the samples. This stabilization mechanism, which has been termed the “nucleation-capture-sulfide encapsulation” process, involves after the oxidation of Fe⁰ to form a core–shell structure for trapping metal ions, where the external oxide layer undergoes mineralization via S(II) sulfide reduction. This microencapsulation-based passivation not only ensures long-term heavy metal immobilization but also preserves the slag’s potential for secondary resource recovery, aligning with circular economy principles. By minimizing environmental leakage risks while retaining metal reclamation feasibility, this approach offers a green and sustainable solution for heavy-metal-laden industrial waste management. Full article

The Mamuju region in West Sulawesi, Indonesia, is a High Background Natural Radiation Area (HBNRA) characterized by a significant enrichment of high field strength elements (HFSEs) and rare earth elements (REEs) within its lateritic deposits. This study investigates the geochemical behavior, mineralogical distribution, and enrichment processes of HFSEs and REEs in lateritic profiles of drill cores and surface samples derived from alkaline volcanic rocks. The mineralogy and geochemical content of HFSEs and REEs in the alkaline bedrocks indicate its potential to become a source of lateritic enrichment. An intense lateritic weathering process leads to the residual accumulation of HFSEs and REEs, particularly in B-horizon soils, where clay minerals and Fe–Al oxides are crucial in element precipitation. Moreover, groundwater redox conditions are a key factor for uranium precipitation in the lateritic profile. The findings provide insight into the potential of lateritic weathering as a natural mechanism for HFSE and REE concentration, contributing to the broader understanding of critical metal resources in Indonesia. These insights have implications for sustainable resource exploration and environmental management in areas with high natural radiation exposure. Full article

The issue of sulfate (SO₄²⁻) pollution in groundwater has already attracted widespread attention from scientists. However, at the large-scale regional level, especially in areas with groundwater overexploitation, the pollution mechanisms and sources of sulfate remain unclear. This study innovatively investigates the spatial distribution characteristics and sources of SO₄²⁻ in the groundwater of the Hutuo River alluvial fan area, an understudied region facing significant environmental challenges due to overexploitation. Utilizing a combination of hydrochemical analysis, multivariate statistical methods, and geostatistical techniques, we reveal that the mean concentration of SO₄²⁻ is significantly higher (127 mg/L) in overexploited areas, with an exceedance rate of 5.1%. Our findings uncover substantial spatial heterogeneity in SO₄²⁻ concentrations, with particularly high levels in the river valley plain (RVP) (175 mg/L) and the upper area of the alluvial fan (UAF) (169 mg/L), which we attribute to distinct human activities. A novel contribution of our study is the identification of groundwater depth as a critical factor influencing SO₄²⁻ distribution (p < 0.001). We also demonstrate that the higher proportion of sulfate-type waters in overexploited areas is primarily due to the accelerated oxidation of sulfide minerals caused by overexploitation. Principal component analysis (PCA) and correlation analysis further identify the main sources of SO₄²⁻ as industrial wastewater, domestic sewage, the dissolution of evaporites, and the oxidation of sulfide minerals. By integrating geostatistical techniques, we present the spatial distribution of sulfate pollution sources at a fine scale, providing a comprehensive and spatially explicit understanding of the pollution dynamics. These results offer a novel scientific basis for developing targeted strategies to control sulfate pollution and protect the sustainable use of regional groundwater resources. Our study thus fills a critical knowledge gap and provides actionable insights for groundwater management in similar regions facing overexploitation challenges. Full article

Mining has significantly shaped Eastern European economies, particularly during their transition from centrally planned to market-oriented systems. While abundant natural resources can lead to a “resource curse” that hinders economic growth, they also offer opportunities for sustainable development if managed effectively. This study investigates the dynamics of mineral resource rents in Eastern Europe, shaped by economic freedom, urbanization, educational achievement, and international trade, from 1990 to 2021. Using methods such as MMQR, AMG Robustness Analysis, CCEMG, fixed effects, cointegration, Granger causality, and unit root tests, the study provides a comprehensive analysis of these relationships. The findings reveal that educational achievement reduces reliance on mineral resource rents by fostering human capital and supporting economic diversification. Urbanization similarly decreases resource dependency by promoting innovation and technological advancement. Trade openness also shows a negative link with mineral rents, suggesting that global integration facilitates shifts toward more advanced, technology-driven sectors. Economic freedom presents mixed results, highlighting the need for strong governance to ensure sustainable and equitable outcomes. This study is novel in integrating these factors into a unified framework, specifically applied to Eastern Europe’s post-communist transition, a region often overlooked in global resource studies. The results contribute most directly to Sustainable Development Goal 4 on Quality Education by demonstrating how human capital development reduces resource dependence and promotes economic resilience, and to Sustainable Development Goal 8 on Decent Work and Economic Growth, by showing that trade openness and economic diversification can drive sustainable economic progress. Ultimately, the study offers actionable insights for balancing economic growth with environmental and social sustainability in transitional economies. Full article

The characterization of historical tailings bodies is crucial for optimizing environmental management and resource recovery efforts. This study investigated the Bielatal tailings dam (Altenberg, Germany), examining its internal structure, material distribution influenced by historical flushing technology, and the spatial distribution of valuable elements. To evaluate the tailings resource potential, drill core sampling was conducted at multiple points at a depth of 7 m. Subsequent analyses included geochemical characterization using sodium peroxide fusion, lithium borate fusion, X-ray fluorescence (XRF), and a scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDX). Particle size distribution analysis via a laser particle size analyzer and wet sieving was conducted alongside milieu parameter (pH, Eh, EC) analysis. A theoretical assessment of the tailings’ potential for geopolymer applications was conducted by comparing them with other tailings used in geopolymer research and relevant European standards. The results indicated average concentrations of lithium (Li) of 0.1 wt%, primarily hosted in Li-mica phases, and concentrations of tin (Sn) of 0.12 wt%, predominantly occurring in cassiterite. Particle size analysis revealed that the tailings material is generally fine-grained, comprising approximately 60% silt, 32% fine sand, and 8% clay. These textural characteristics influenced the spatial distribution of elements, with Li and Sn enriched in fine-grained fractions predominantly concentrated in the dam’s central and western sections, while coarser material accumulated near injection points. Historical advancements in mineral processing, particularly flotation, had significantly influenced Sn distribution, with deeper layers showing higher Sn enrichment, except for the final operational years, which also exhibited elevated Sn concentrations. Due to the limitations of X-ray fluorescence (XRF) in detecting Li, a strong correlation between rubidium (Rb) and Li was established, allowing Li quantification via Rb measurements across varying particle sizes, redox conditions, and geological settings. This demonstrated that Rb can serve as a reliable proxy for Li quantification in diverse contexts. Geochemical and mineralogical analyses revealed a composition dominated by quartz, mica, topaz, and alkali feldspars. The weakly acidic to neutral conditions (pH 5.9–7.7) and reducing redox potential (Eh, 570 to 45 mV) of the tailings material indicated a minimal risk of acid mine drainage. Preliminary investigations into using Altenberg tailings as geopolymer materials suggested that their silicon-rich composition could serve as a substitute for coal fly ash in construction; however, pre-treatment would be needed to enhance reactivity. This study underscores the dual potential of tailings for element recovery and sustainable construction, emphasizing the importance of understanding historical processing techniques for informed resource utilization. Full article

Wetland lakes are crucial ecosystems that serve as vital ecosystems that harbor rich biodiversity and provide essential ecological services, particularly in regulating regional water resources, purifying water quality, and maintaining ecological equilibrium. This study aims to conduct an in-depth investigation into the hydrochemical characteristics and their controlling factors during the dry season of the Hengshui Lake wetland system. By collecting water samples from the lake and shallow groundwater, and using water chemistry diagrams, ion ratios, mineral saturation indices, and multivariate statistical methods, the study systematically analyzes the hydrochemical characteristics of Hengshui Lake Wetland and its controlling factors. The results show: there is significant stratified differentiation in the water chemical composition: the lake water is weakly alkaline and fresh, while the shallow groundwater is highly mineralized and saline. Both are dominated by Na⁺, Mg²⁺, SO₄²⁻, and Cl⁻. Significant differences exist in water chemistry types between the lake and shallow groundwater. The lake water exhibits homogenized characteristics with a dominant SO₄·Cl·HCO₃-Na·Mg type, whereas shallow groundwater displays five distinct hydrochemical facies indicative of multi-source recharge processes. Evaporation–rock interaction mechanisms dominate the system, as evidenced by a Gibbs diagram analysis showing evaporation crystallization as the primary control. Ion ratio calculations demonstrate synergistic effects between silicate weathering and evaporite dissolution, while mineral saturation indices confirm cooperative processes involving calcite/dolomite oversaturation and ongoing gypsum dissolution. Cation exchange indexes combined with chloro-alkaline indices reveal unidirectional recharge from lake water to shallow groundwater accompanied by active cationic exchange adsorption. Although the wetland predominantly maintains natural hydrological conditions, elevated γ(NO₃⁻)/γ(Na⁺) ratios in nearshore zones suggest initial agricultural contamination infiltration. This study shows that, as a typical example of a closed wetland, the hydrochemistry evolution of Hengshui Lake during the dry season is primarily dominated by the coupled effects of evaporation and rock–water interaction, with silicate weathering and evaporation rock dissolution as secondary factors, and human activity having a weak influence. The findings provide new insights into the understanding of the hydrochemical evolution process and its controlling factors in closed lakes, offering valuable data support and theoretical basis for the ecological restoration and sustainable management of closed lakes. Full article

In the Yuheng mining area (Jurassic coalfield, northern Shaanxi, China), the Yan’an Formation groundwater is characterized by elevated salinity, posing challenges for mine water pollution control and regional water resource management. However, the spatial distribution patterns and formation mechanisms of this high-salinity groundwater remain poorly studied. This study integrates hydrogeochemical data from 18 coal mines, analyzing the spatial salinity variations, major ion compositions and isotopic signatures. Combined with the evolution characteristics of ancient sedimentary environments and the composition analysis of rock salt minerals in the coal rock interlayers, the formation mechanism of high salinity water was explored. The results indicate that the groundwater mineralization degree of the Yan’an Formation in the Jurassic strata encountered in the Yuheng mining area is the highest, showing a decreasing trend upwards. On the plane, the western and northern regions are generally higher than the eastern and southern regions. The highest mineralization level of groundwater can reach 36.25g/L, and the high mineralization hydrochemical type is mainly SO₄-Na·Ca type, with occasional Cl-Na type in areas with extremely high mineralization level. The cause analysis shows that the highly mineralized groundwater in the Yuheng mining area comes from atmospheric precipitation, which infiltrates and dissolves salt rocks. In addition, the mining area is located in the arid area of northern Shaanxi, with insufficient water supply and no obvious structural faults, and has good sealing properties, thus exhibiting the characteristics of high mineralization. These mechanisms provide a formation model for the high-salinity groundwater in Jurassic coal-bearing strata, offering critical implications for predictive hydrogeochemical modeling and sustainable water management in arid mining regions. Full article

Urban minerals are secondary resources with economic value that can be recycled and utilized, including iron and steel, non-ferrous metals, rubber, and others. Accurately estimating the quantities of various components is a critical element in the urban mining operations that support sustainable resource management. To achieve this, ontology construction was employed to systematically define and structure the relationships among different entities in the domain. Knowledge graphs were developed to identify the constituent elements and mineralization process of iron and steel, contributing to improved sustainability in urban resource utilization. The knowledge graphs were constructed using a top-down approach and stored in a Neo4j database. When a knowledge graph of iron and steel components is constructed, the iron and steel products are classified into 5 major categories and 14 subcategories. The knowledge graph of the iron and steel mineralization process is divided into five iron and steel mineralization stages and combines industrialization and urbanization to represent the factors that play a role in the iron and steel mineralization process. By leveraging ontology construction, the knowledge graph can improve the efficiency of refining and analyzing data in urban mineral-related fields. This, in turn, provides an essential data basis for establishing a circular economic system for iron and steel industry resources and advancing sustainability-oriented urban mining practices. Full article

Groundwater plays a leading role in ecological environment protection in semi-arid regions. The Huangshui River Basin is located in the Tibetan Plateau and Loess Plateau transition zone of semi-arid areas. Its ecological environment is relatively fragile, and there is an urgent need for systematic study of the basin to develop a groundwater environment and realize the rational and efficient development of water resources. In this study, methodologically, we combined the following: 1. Field sampling (271 groundwater samples across the basin’s hydrogeological units); 2. Comprehensive laboratory analysis of major ions and physicochemical parameters; 3. Multivariate statistical analysis (Pearson correlation, descriptive statistics); 4. Geospatial techniques (ArcGIS kriging interpolation); 5. Hydrochemical modeling (Piper diagrams, Gibbs plots, PHREEQC simulations). Key findings reveal the following: 1. Groundwater is generally weakly alkaline (pH 6.94–8.91) with TDS ranging 155–10,387 mg/L; 2. Clear spatial trends: TDS and major ions (Na⁺, Ca²⁺, Mg²⁺, Cl⁻, SO₄²⁻) increase along flow paths; 3. Water types evolve from Ca-HCO₃-dominant (upper reaches) to complex Ca-SO₄/Ca-Cl mixtures (lower reaches); 4. Water–rock interactions dominate hydrochemical evolution, with secondary cation exchange effects; 5. PHREEQC modeling identifies dominant carbonate dissolution (mean SIcalcite = −0.32) with localized evaporite influences (SIgypsum up to 0.12). By combining theoretical calculations and experimental results, this study reveals distinct hydrochemical patterns and evolution mechanisms. The groundwater transitions from Ca-HCO₃-type in upstream areas to complex Ca-SO₄/Cl mixtures downstream, driven primarily by dissolution of gypsum and carbonate minerals. Total dissolved solids increase dramatically along flow paths (155–10,387 mg/L), with Na⁺ and SO₄²⁻ showing the strongest correlation to mineralization (r > 0.9). Cation exchange processes and anthropogenic inputs further modify water chemistry in midstream regions. These findings establish a baseline for sustainable groundwater management in this ecologically vulnerable basin. Full article