Search Results (2,477)

As food demand increases, agricultural practices have evolved, prompting increased exploration of sustainable ecological techniques and utilization of plant-associated microorganisms. In this context, plant fitness has been enhanced by plant growth-promoting microorganisms (PGPM), which stimulate growth through direct mechanisms, such as improved nutrient availability and phytohormone production, as well as indirect mechanisms, including protection against phytopathogens and suppression of soil-borne diseases. However, these innate capabilities of PGPM can be further improved through genomic modification or editing. This article reviews advances in the genomic engineering of plant-beneficial microorganisms as tools to enhance their positive effects on crop performance and environmental remediation. The genetic modification strategies analyzed here include random mutagenesis, targeted genome editing (such as CRISPR-Cas), gene over-expression, genome shuffling, RNA interference, metabolic pathway engineering, and synthetic biology approaches. These tools have enabled the optimization of functions, such as nitrogen fixation, phosphate solubilization, secondary metabolite production, biocontrol, stress tolerance, and bioremediation. However, we propose expanding the discussion of their regulation and use in various countries. Additionally, these modifications must be efficient and safe for the beneficial microbiota associated with the target crop, as well as for humans, animals, and the environment, all of which depend on sustainable agricultural practices. Full article

Perfluorooctanesulfonate (PFOS) is a persistent pollutant in soils due to its exceptional chemical and biological stability. Pyrolysis has been recognized as an effective technology for the remediation of PFOS-contaminated soil. However, its large-scale application faces challenges such as the requirement of high temperatures, long residence time, and corrosive off-gas treatment. The application of additives during pyrolysis is a promising strategy to overcome these challenges. In this study, six additives (Fe₂O₃, Fe₃O₄, CaO, Ca(OH)₂, kaolinite, and MgO) were employed to improve PFOS removal from soil by pyrolysis. The effects of temperature, residence time, and removal efficiency with additives on the PFOS decomposition mechanism and economic benefits were systematically investigated. The results showed that all additives could allow for effective PFOS removal at a relatively low temperature (350 °C) and with a short residence time (30 min). Fe₂O₃ and CaO at a 5% dosage exhibited PFOS removal efficiency reaching 95.19% and 95.49%, respectively, which were 21.00% higher than that of the no-additive system. The thermodynamic analysis showed that the additives could reduce the activation energy (Ea) of PFOS pyrolysis, among which Fe₂O₃ showed the most significant effect (54.24 kJ/mol). Although additives exerted no significant effect on the type of PFOS decomposition products in soil, they effectively reduced the emission of acidic off-gases. Among them, CaO and Ca(OH)₂ showed the most significant reduction by forming inorganic fluorides, followed by Fe₂O₃ and Fe₃O₄, through providing active sites. Economic analysis indicated that CaO had the lowest cost for PFOS removal (2.86 CNY/mg), followed by Fe₂O₃ (2.88 CNY/mg). Comprehensively considering PFOS removal efficiency, decomposition mechanism, economic cost, and pH of treated soil, Fe₂O₃ was identified as the optimal additive. This study provides new insights into the PFOS pyrolysis in soils, and proposes an energy-efficient remediation approach by reducing temperature, residence time, Ea, and off-gas emissions, which offers support for the large-scale application of this technology. Full article

The use of sewage sludge for the bioremediation of hydrocarbon-contaminated soils remains insufficiently documented, particularly regarding microbial dynamics and material behavior during treatment. Although petroleum-hydrocarbon contamination severely disrupts soil functions, sewage sludge—through its high organic matter content, active bacterial communities, and fine mineral fraction—offers potential for the sustainable remediation of such soils. Three soil–sludge mixtures (P1:N1, P2:N1, P1:N2) were monitored to assess hydrocarbon degradation, bacterial community dynamics, and material behavior. Hydrocarbon-degrading and hydrocarbon-tolerant bacteria remained active, while sludge-derived Enterobacteriaceae declined below detection limits. Enrichment cultures of the sludge yielded three hydrocarbon-degrading strains (Providencia alcalifaciens IBBN1, Klebsiella pneumoniae IBBN2, Acinetobacter tandoii IBBN3), highlighting the metabolic potential of the active microbial communities. A moderate increase in surfactant concentrations reflected both residual anionic surfactants and biosurfactant production by these consortia, facilitating hydrocarbon mobilization. Total petroleum hydrocarbons (TPH) decreased by 45–60% (IR), and GC-FID analysis showed preferential degradation of C10–C40 fractions. Heavy-metal concentrations remained stable, indicating no geochemical changes or inhibitory effects on bacterial activity. Overall, the results confirm the potential of sewage sludge as a sustainable amendment that accelerates hydrocarbon biodegradation and supports integrated soil-restoration strategies. Full article

Traditional adsorbents, such as clay minerals, mainly target metal cations, which limits their effectiveness in mining soils where multiple metals and oxyanionic species coexist. To address this limitation, we evaluated amino-functionalized UiO-66-NH₂ as a stabilizing amendment capable of immobilizing both anionic and cationic metal species. This study evaluated its stabilization performance for vanadium (V), chromium (Cr), nickel (Ni), and zinc (Zn) in typical mining soils. Soil samples were amended with 1%, 2%, and 3% dosages and incubated for 50 days to systematically analyze leaching behavior, speciation transformation, and microbial community responses. At 50 days, the 1% UiO-66-NH₂ treatment reduced the leaching concentrations of V, Cr, Ni, and Zn by 90.42%, 59.72%, 90.12%, and 90.71%, respectively. Although Cr showed its highest reduction efficiency under the 3% treatment, the 1% dosage provided a practical compromise for multi-metal stabilization rather than a universal optimum. The stabilization process was primarily driven by surface complexation and ion exchange, which facilitated the transformation of metals into stable oxidizable forms. The amendment increased soil organic matter (SOM) and cation exchange capacity (CEC), triggering competitive adsorption and increasing the mobility of Zn and Ni. Microbial profiling revealed a successional shift toward resilient taxa, specifically the proliferation of Actinomycetota and Arthrobacter. These findings established that a 1% UiO-66-NH₂ amendment provides a robust and ecologically compatible strategy for the sustainable remediation of complex mining-impacted environments. Full article

Water scarcity has become a major challenge for agriculture, particularly in arid and semi-arid regions where irrigation is essential for sustaining crop and forage production. As freshwater supplies face growing pressure from climate change, urban growth, and industrial use, there is increasing interest in exploring alternative water sources to support sustainable agriculture. Produced water, a byproduct of oil and gas extraction, may represent an alternative water source in water-limited regions like the southwestern United States and the Middle East. However, raw produced water often contains high levels of salinity, trace metals, hydrocarbons, and naturally occurring radioactive materials, which cause risks to soils, crops, livestock, and food systems. This review synthesizes peer-reviewed studies up to January 2026 and reports on the agricultural application of treated produced water, focusing on its effects on soil properties, crop growth, yield, and forage nutritive quality. Existing research shows that treated produced water could be used for grain as well as forage crops under controlled conditions, but poorly treated and managed applications can lead to increases in soil salinity, structural degradation, reduced nutrient uptake, and hindered crop performance. In forage systems, irrigation with treated produced water has also been associated with changes in nutritive value, increasing concerns for livestock health. Several knowledge gaps remain, including limited long-term field studies, insufficient information on crop-specific contaminant thresholds, incomplete assessment of treatment and remediation strategies under different environmental conditions, and the absence of a consistent framework for classifying the chemistry of treated produced water for agricultural applications. Addressing these gaps through integrated soil, crop, and water research and the development of clear policies and guidelines is essential for determining whether treated produced water can be safely and sustainably used in agriculture under growing water scarcity. Full article

Accurate identification of HMs contamination in mine tailings is essential for understanding pollution and supporting remediation. However, conventional laboratory monitoring is labor-intensive, time-consuming, and spatially discontinuous, while UAV hyperspectral inversion is limited by spectral inconsistency, unstable performance under small-sample conditions, and insufficient interpretability. Here, we developed an interpretable UAV–laboratory synergistic framework for Cd and Pb mapping in the Yitong open-pit mine. Forty site-level soil samples, composited from 200 subsamples, were linked with UAV hyperspectral observations. Direct Standardization was used to harmonize UAV and laboratory spectra. A weighted voting ensemble (RF, GBDT, and XGBoost) achieved the best performance (R² = 0.85), outperforming the individual models and showing slightly higher stability than CNN (R² = 0.84). Environmental covariates (pH, SOM, SMC) revealed distinct metal-specific prediction patterns: Cd was mainly associated with pH–SOM interactions, whereas Pb was more strongly associated with SOM–SMC coupling. SHAP and Grad-CAM identified sensitive spectral regions, with Cd linked to the 440–580 nm range and Pb to the 720–740 nm range. Overall, this study provides an integrated framework that combines spectral transfer correction, stable multi-model inversion, and mechanism-oriented interpretability for HMs monitoring in complex mining environments. Full article

This study investigates the influence of inside-trapped water and remedial grouting on the vertical bearing behaviour of suction bucket foundations in sand through 1 g laboratory model tests. The tests were designed to compare the relative responses of different trapped-water and grouting conditions under the same model scale, sand preparation procedure, and loading protocol. Two target trapped-water conditions were considered: a condition without an observable continuous water layer beneath the bucket lid and a condition with an initial trapped-water thickness of approximately 2 cm. These conditions were controlled and verified before loading using the scale attached to the transparent bucket wall and the underwater camera monitoring system. The results show that inside-trapped water modifies the vertical load-transfer path between the bucket lid and the internal soil plug. When a water layer exists beneath the lid, direct lid–soil plug contact is weakened, and the foundation resistance relies more strongly on skirt-side resistance and the resistance mobilized near the bucket rim. Under cyclic vertical loading, the trapped-water case exhibited larger cumulative displacement and a lower post-cyclic bearing response than the no-trapped-water case. The secant cyclic stiffness showed a continuous increase in the no-trapped-water case, whereas a rise-then-fall trend was observed in the trapped-water case, which may be associated with cyclic densification, soil plug disturbance, changes in lid–soil plug contact, and possible local pore pressure development. Remedial grouting filled the trapped-water space beneath the bucket lid and partially restored the lid–soil plug load-transfer path. Under the present model test conditions, the post-cyclic dimensionless bearing capacity of the grouted cases increased by approximately 13–16% relative to the ungrouted trapped-water case. The grouting cases with different bentonite contents showed similar recovery trends within the limited dataset, suggesting that the improvement was mainly related to filling and sealing the trapped-water space rather than to the intrinsic strength of the grout material. Full article

Heavy metal pollution from coal gangue severely degrades mine soil structure and threatens landscape ecological stability. Particularly, γ-polyglutamic acid (γ-PGA), a green biopolymer, offers potential applications for pollution remediation while supporting ecological restoration. To evaluate γ-PGA’s efficacy in immobilizing Pb, Cd, and Zn in gangue-based soil and clarify its regulatory mechanism for landscape-friendly remediation, soil samples from a 3-year-weathered gangue hill in the Liupanshui mining area were subjected to indoor leaching experiments with different γ-PGA doses, combined with material characterization and Density Functional Theory (DFT) simulations. The results showed that the optimal γ-PGA dose was 6 g/kg, achieving 93.25% Pb immobilization and reducing Cd/Zn migration risk by over 30%; γ-PGA acted via carboxyl-amide dual-site chelation and hydrogen-bonded agglomeration, forming stable aggregates that inhibited metal migration. DFT calculations confirmed strong chelation for Cu²⁺ (−59.54 kcal/mol, BSSE-corrected: −57.23 kcal/mol), while Pb²⁺ and Cd²⁺ showed weaker binding (−8.32 kcal/mol and −5.67 kcal/mol, BSSE-corrected: −6.15 kcal/mol and −3.89 kcal/mol, respectively), indicating multi-pathway immobilization mechanisms. This study provides a theoretical basis for applying γ-PGA in mine landscape ecological restoration. Full article

Heavy metal contamination in soil and the resulting groundwater pollution are common at many brownfield sites. Soil washing, which dissolves contaminants into a washing solution to separate them from the soil matrix, has emerged as a promising remediation strategy. This study assessed the feasibility of applying soil washing to Pb-contaminated soil collected from an industrial area within the Trieste Port Authority (Italy) through a series of leaching tests. Batch tests were conducted using ethylenediaminetetraacetic acid (EDTA)-based extractants combined with various reducing agents to identify the most effective and environmentally sustainable washing solution. The results show that coupling EDTA with hydroxylamine hydrochloride or sodium dithionite significantly enhanced Pb solubilisation compared with EDTA alone, with dithionite emerging as the most suitable reducing agent due to its lower toxicity and reduced environmental impact. Sequential extraction tests revealed that up to 50% of total Pb could be removed after repeated washing cycles. Column leaching tests further confirmed the high efficiency of the EDTA–sodium dithionite system, achieving Pb removal rates of approximately 70% under continuous flow conditions. Overall, the results demonstrate that EDTA combined with low-dose sodium dithionite provides an effective and practical remediation strategy for heavily polluted industrial soils. Full article

Diesel is a major soil contaminant that poses significant environmental risks, making its removal essential. This study investigates the synergistic application of thermal desorption (TD) and thermal plasma for the remediation of diesel-contaminated soil, while simultaneously converting desorbed contaminants into valuable gaseous products. Artificially contaminated soil (25 g/kg) was treated by TD at 250–300 °C and the resulting off-gas and volatilized diesel were subsequently processed in a thermal plasma system. Soil samples were characterized using CHNS, EDX, FTIR, and TGA/DTG analyses, while gas composition was determined using a gas analyzer. The results demonstrate that TD achieved diesel removal efficiencies of up to 86% at 300 °C and 65% at 250 °C. TD off-gas and volatilized diesel were predominantly converted into synthesis gas (H₂ + CO) in a thermal plasma environment, with H₂ and CO concentrations reaching up to 15.49 vol% and 7.61 vol%, respectively, depending on the plasma-forming gas, carrier gas flow rate, and remediation temperature. Thermal treatment of diesel-contaminated soil significantly altered key physicochemical properties, including reduced organic matter content, increased soil compaction, and temperature-dependent shifts in pH and nitrogen speciation (decreased NO₃⁻-N and increased NH₄⁺-N). These changes were accompanied by enhanced phosphorus availability, indicating substantial thermally induced transformation of soil nutrients. Phytotoxicity assessment using Lepidium sativum in a soil leachate-based bioassay indicated that higher treatment temperature (300 °C) increased toxicity and inhibited plant growth, whereas treatment at 250 °C resulted in lower phytotoxicity. These findings highlight the adaptability of the proposed combination of methods enabling effective soil remediation while supporting energy recovery. Full article

Cadmium (Cd) and lead (Pb) co-contamination in construction and demolition waste landfill soils presents a significant challenge to ecosystem health, necessitating effective remediation strategies. This study investigated a synergistic approach combining a composite amendment (compost, superphosphate, desulfurized gypsum) with seven plant species to elucidate the interactions driving metal immobilization and phytoextraction. The amendment significantly altered soil properties: it reduced total Cd while increasing its bioavailability, and enhanced soil fertility (e.g., elevated organic matter and total nitrogen). Plant responses varied: Solanum americanum Mill. and Tagetes patula L. exhibited high Cd phytoextraction capacity, whereas Lolium perenne L. sequestered Cd/Pb primarily in roots. The bacterial community shifted from an oligotrophic, stress-tolerant state (e.g., Sphingomonas-dominated) in contaminated soil to a copiotrophic, functionally active state (e.g., Streptomyces-enriched) in amended soil. Community structure was strongly correlated with available Cd, pH, and nutrient levels. Key microbial biomarkers were specifically enriched in different plant rhizospheres. In contrast, the fungal community exhibited minimal responsiveness. These findings demonstrate that remediation efficiency is governed by an integrated “amendment–plant–microbe” framework: amendments regulate metal bioavailability, plants execute extraction or stabilization, and the restructured microbiome supports nutrient cycling and plant health. This integrated remediation strategy directly supports the Sustainable Development Goals of the 2030 Agenda, especially on environmentally sound management of chemicals and wastes and land degradation neutrality. This mechanistic understanding underscores the necessity of combined biological and chemical strategies for sustainable remediation of co-contaminated soils, ultimately enabling ecological reclamation and safe recycling of such urban marginal lands into productive uses. Full article

A lightweight and high-efficiency microwave-absorbing material was developed via an in situ solvothermal pyrolysis strategy by anchoring sphere-like Fe₃O₄ nanostructures onto bamboo-derived porous carbon (BPC). The resulting composites preserve the intrinsic anisotropic honeycomb architecture of bamboo while introducing uniformly distributed magnetic nanoparticles, enabling synergistic dielectric–magnetic loss. Electromagnetic parameters, alongside impedance matching, were successfully modulated through the optimization of precursor concentrations. Of the evaluated materials, BPC-0.9 stood out for its intense attenuation, recording an RL_min of −45.17 dB at a 1.8 mm thickness. Furthermore, a significant effective absorption bandwidth of 6.65 GHz was attained by the BPC-0.6 sample at only 2.2 mm. Several factors contribute to the boosted efficiency, starting with conductive and interfacial polarization losses paired with multiple scattering events. Furthermore, magnetic loss components, encompassing eddy current effects as well as natural and exchange resonances, play a pivotal role in optimizing the material’s response. Furthermore, radar cross-section (RCS) modeling reveals a substantial reduction of 19.9 dB·m², verifying the material’s viability for real-world stealth technologies. Our findings offer a straightforward methodology for fabricating magnetic carbon structures from biomass with adjustable dielectric responses, underscoring their potential in high-performance energy conversion and low-density microwave absorption. Full article

Heavy metals in the soil inhibit plant growth, which significantly reduce the crop yield and quality. Natural Resistance-Associated Macrophage Proteins (NRAMP) are widely distributed on the plasma and vacuolar membranes of plant roots, stems, and leaves. The NRAMP gene family plays a crucial role in modulating plant heavy-metal uptake, sequestration, distribution, and translocation, while the molecular evolution and mechanisms underlying these processes remain unclear. Here, we reviewed recent progress on plant NRAMP genes, focusing on their structural characteristics and functions in the absorption, transport, accumulation, and detoxification of various heavy metals. Furthermore, we performed an evolutionary analysis of NRAMP in green plants, indicating expansion and tandem duplication in ferns. In addition, their key amino acid sequences and secondary structures were highly conserved across plant species. The expression of diverse tissue showed that NRAMP genes displayed distinct spatial regulation in the leaves and roots. We also explored the underlying molecular mechanisms and regulatory pathways by which NRAMP genes influence heavy metal uptake. Therefore, by integrating structural conservation, molecular evolution, tissue- and single-cell expression patterns, ion-stress-responsive expression, regulatory pathways, and the Cd–Mn nutrient–toxin trade-off, this review provides a framework for identifying unresolved NRAMP functions and for guiding future strategies in low-heavy-metal crop breeding, metal homeostasis engineering, and phytoremediation. Full article

To improve the removal efficiency of sulfamethoxazole (SMX) in soil and to elucidate the role of soil organic matter (SOM) in peroxydisulfate (PDS)-based in situ chemical oxidation, a biochar-supported sulfidated nanoscale zero-valent iron (BC@S-nZVI)-activated PDS system was constructed in this study. The removal behavior and removal mechanisms of SMX were systematically compared between aqueous and soil systems, and the regulatory role of SOM was further clarified. Characterization results showed that BC@S-nZVI was successfully constructed with a composite interface consisting of a biochar support framework, an Fe⁰ core, and surface Fe-S structures. Under the optimized conditions, the BC@S-nZVI/PDS system achieved 92.9% removal of SMX within 120 min in the aqueous system, which was significantly higher than that of the nZVI/PDS and BC/PDS systems. In the soil system, the removal efficiency of SMX reached 74.4% within 120 min, and further increased to 91.3% after targeted removal of SOM. Results from radical quenching experiments, electron paramagnetic resonance (EPR) spectroscopy, and chemical probe tests demonstrated that ^•OH and SO₄^•− were the dominant reactive species driving SMX degradation in the aqueous system, while ¹O₂ played an auxiliary role. In contrast, in the soil system, SOM, acting as a natural reductive component, competitively consumed ^•OH and SO₄^•−, thereby markedly suppressing the radical oxidation pathway. Compared with these radical species, ¹O₂ exhibited stronger resistance to background interference and became the key reactive species responsible for the sustained transformation of SMX in soil. These findings demonstrate that the BC@S-nZVI/PDS system has considerable potential for the remediation of antibiotic-contaminated soils and reveal a mechanistic shift from radical-dominated to non-radical-dominated pathways under the interference of soil organic components. Full article

Contamination of soils by petroleum hydrocarbons is a long-standing environmental and public-health issue in oil-producing areas. This study compared natural attenuation and biostimulation using date palm waste for the remediation of crude-oil-contaminated soil collected near the North Oil Company facilities in Kirkuk, Iraq (0–10 cm). The experiment was conducted as an outdoor semi-field, pot study under a rain shelter over 160 days, using 2 kg of soil per pot; palm waste (<5 mm) was added at 500 g per pot in the biostimulation treatment. This study provides preliminary semi-field evidence from Iraq using locally available date palm waste under semi-arid outdoor conditions. Gas chromatography with flame ionization detection (GC–FID) was used to measure total petroleum hydrocarbons (TPH; C8–C40), while gas chromatography–mass spectrometry (GC–MS) was used to measure 18 priority polycyclic aromatic hydrocarbons (PAHs), grouped into 2–3- and 4–6-ring categories; the microbial number was measured as colony-forming units (CFU). Biostimulation reduced TPH from 38,751 mg kg⁻¹ at day 0 to 9205 mg kg⁻¹ by day 40 (76.2% reduction), which was later sustained to 4717 mg kg⁻¹ by day 160 (87.8% reduction). Natural attenuation showed relatively slower and smaller reductions over the same period. Full article