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PubMed2026

Biomass burning contributions to Mexico City's atmospheric CO2 estimated using a multi-isotope approach.

Fossil fuel combustion dominates anthropogenic emissions worldwide; however, special attention should be addressed to biomass burning, since it is an increasingly important contributor under warmer, drier fire-weather conditions exacerbated by climate change. These emissions could impact the atmospheric composition of heavily urbanized environments. To assess the influence of biomass burning, along with fossil fuels combustion and soil and plant respiration on Mexico City's atmospheric composition, we conducted a year-long (December 2023-December 2024) isotopic monitoring of atmospheric CO2, combining radiocarbon (Δ14C), CO2 stable isotopes (δ13C, δ18O), and CO/CO2 ratios. Once defined the isotopic signatures and the characteristic CO/CO2 that describe the sources, we performed Monte Carlo simulations under two tracer modalities (Δ14C + CO/CO2 and Δ14C + CO2 stable isotopes) for source apportionment. Results show that during the dry season, particularly in March-April, atmospheric Δ14C values approached and overlapped background levels despite Mexico City's fossil-fuel dominance, indicating enhanced non-fossil inputs. Moreover, backward HYSPLIT trajectories supported that these elevated Δ14C values coincided with regional wildfire activity. Monte Carlo results attributed up to ∼34 %-60 % of local CO2 to biomass burning in April, followed by March with contributions of ∼31 %-49 %. Since these biomass burning figures contrast with the official emissions inventory of Mexico City metropolitan area, which assigns <1 % of total CO2 emissions to biomass burning, this study could exhibit the emissions inventory underestimation of this source, and thus, the need to reassess and incorporate top-down isotopic constraints in fire-affected urban regions.

Mexico↗

PubMed2026

Antarctic Peninsula soil carbon stock and efflux: A complex interplay of soil properties and heavy metals.

This study establishes a quantitative framework for understanding surface soil carbon dynamics and ecosystem connectivity in Fildes Peninsula and Ardley Island, King George Island, South Shetland Islands, Antarctic Peninsula. The mean soil organic carbon (SOC) stock across all study sites was 1.10 ± 1.93 kg C/m². Restricting net carbon balance analysis to Fildes Peninsula, where soil respiration (Rs) data were available, yielded a site-specific SOC stock of 0.45 ± 0.45 kg C/m². Scaling Rs to a realistic 120-day active season and assuming stable SOC stocks resulted in estimated annual carbon loss of 15 g C/(m2·yr), equivalent to 3.3 % of standing SOC. Comprehensive sensitivity analyses spanning plausible winter respiration (0 %-20 % of summer rates) and annual change in SOC stocks (-1 %-2 %) consistently supported a net carbon sink, with turnover rates constrained to 3.3 %/yr-4.7 %/yr. Principal component analysis showed that ornithogenic processes as the dominant control on SOC, total nitrogen (TN), zinc (Zn), copper (Cu), and cadmium (Cd) provide a clear multivariate signature of marine-derived nutrient, while Pb was decoupled from this gradient and associated instead with fine-particle size controls. These results reveal dual but independent drivers of soil metal enrichment in this region. Despite their limited spatial extent, ornithogenic soils store disproportionately large carbon pools. Overall, this integrated analysis reveals how marine-terrestrial subsidies regulate Antarctic carbon cycling and provides a quantitative and reproducible framework for assessing carbon dynamics under ongoing climate change.

Antarctic Regions↗

PubMed2026

Enrichment of Lysobacter in a long-term organically managed agricultural field with low soilborne disease incidence.

Disease-suppressive soils, in which soilborne pathogens are naturally suppressed, offer a promising model for sustainable crop protection, particularly in organic farming systems where chemical disease control options are limited. Although disease suppression in these soils is considered to rely on biological control, the underlying mechanisms remain poorly understood. In this study, we investigated soil from a long-term organically managed field in Shiga Prefecture, Japan, where soilborne disease incidence has remained consistently low, to identify bacterial community features potentially associated with this field. The 16S rRNA gene amplicon sequencing indicated that this soil harbored a bacterial community distinct from those of nearby agricultural soils. Following the application of organic compounds, the genus Lysobacter, a taxon with known antagonistic activity against plant pathogens, was markedly enriched in response to proteinaceous organic inputs. This enrichment was consistent across sampling times and specific to certain proteinaceous organic inputs, whereas minimal effects were observed on chitin, N-acetyl-d-glucosamine, or cysteine. Broader soil surveys indicated that Lysobacter enrichment was not strictly associated with whether soils had been managed under organic or conventional farming practices. Stepwise multiple regression analysis identified 10 co-occurring bacterial genera that were strongly associated with Lysobacter abundance. These findings highlight condition-dependent Lysobacter enrichment as a characteristic microbial response to proteinaceous organic amendments in this low-disease-incidence field and provide microbial insights that may inform microbiome-based strategies for sustainable soil management.

Lysobacter↗

PubMed2026

PGPR inoculation and growth enhancement of crops cultivated in hydroponic systems.

Plant growth-promoting rhizobacteria (PGPR) are ubiquitous rhizosphere microorganisms that promote plant health through various mechanisms. Although the study of PGPR inoculants in soil has been done for ages, their application in hydroponic systems has received relatively limited attention. This review identifies PGPR inoculants that are commonly used in hydroponics, methods of application, and their effects on plant growth and nutrient use efficiency. Literature shows that PGPR inoculants improve plant performance in controlled hydroponic systems through the production of growth-stimulating substances, nitrogen fixation, and improved nutrient acquisition. However, the plant growth responses are highly variable depending on the composition of nutrient solutions, environmental factors, crop and microbe species, and the type of hydroponic system. The review identifies various challenges of PGPR inoculation in hydroponic systems and future research directions to address the current gaps. Generally, the productivity of hydroponic systems can be enhanced through advanced inoculation strategies and the development of suitable carrier materials to improve inoculant survival, viability, and functions. Emphasis should also be placed on designing system-specific microbial consortia and Synthetic communities that are tailored to the unique ecological conditions of hydroponic systems.

Hydroponics↗

PubMed2026

Dynamics of soil fungal communities restored with biochar from a quarry site.

Quarrying activities have intensified due to population expansion, leading to landscape degradation and ecological destruction. Quarry restoration is usually mandatory in Hong Kong, China. Although biochar is used for sustainable soil amendment, its effectiveness in restoring quarry soil with poor properties has rarely been investigated. A 24-month field study was conducted to evaluate the ecological feasibility of restoring a quarry site by using native species (that is, Castanopsis fissa and Cyclobalanopsis edithiae) and biochar amendment. The results revealed that after 24 months, the application of biochar increased the organic carbon, phosphorus and potassium of the vegetated soil by at least 120 %, 31 % and 12 %, respectively, due to higher cation exchange capacity and better plant growth. The relative abundance of Ascomycota and Basidiomycota increased by 24 % and 47 % with biochar application when C. fissa was planted, which was likely associated with the improved nutrient cycling and soil fertility. Even though adding biochar to bare soil was found to increase the complexity of fungal co-occurrence networks, biochar application only increased fungal diversity in vegetated quarry soil but usually reduced its fungal richness. Moreover, fungal co-occurrence networks in vegetated soil became less complex, suggesting that biochar potentially helped plants to assemble specific, beneficial fungal communities. This effect is most pronounced in the soil planted with C. edithiae, where the structure of fungal communities after 24 months was significantly different from that at other restoration times. This study identifies key fungal phyla enhanced by biochar in quarry soil and provides an effective strategy for facilitating the restoration and management of degraded lands, especially quarry sites.

Charcoal↗

PubMed2026

Desert-derived Ensifer sp. SA403 enhances potato salt tolerance by reshaping rhizosphere microbiome functions and host responses.

Soil salinization increasingly threatens global food security, and potato (Solanum tuberosum L.), a moderately salt-sensitive crop, is particularly vulnerable to saline soils. Plant growth-promoting rhizobacteria (PGPR) offer a promising strategy to improve crop performance, yet how PGPR interact with native microorganisms to enhance potato salt tolerance remains poorly understood. In this study, we identified a desert-derived PGPR strain, Ensifer sp. SA403, which substantially enhanced potato performance under high salinity across sterile, non-sterile and field conditions. Physiologically, inoculation with SA403 reduced shoot Na⁺ accumulation and increased the K⁺/Na⁺ ratio; notably, these effects were markedly stronger in non-sterile substrates than under sterile conditions, indicating that SA403-mediated ion homeostasis relies on cooperation with the resident microbiota rather than on the strain acting alone. Metagenomic profiling indicated that SA403 strain reshaped rhizosphere communities, significantly enriching beneficial taxa such as Priestia and Bradyrhizobium, and upregulated functional pathways involved in glutathione and sulfur metabolism. Furthermore, host transcriptomic analyses showed that SA403 modulated plant responses to salt stress, with differentially expressed genes enriched in jasmonic acid signaling, ethanolamine metabolism and amino-acid biosynthesis pathways. Field trials on saline soils confirmed that SA403 significantly increased seedling emergence and tuber weight. Together, our results demonstrate that SA403 functions as a biological mediator that optimizes rhizosphere microecology and coordinates ion balance and host signaling to enhance potato salt tolerance. These findings support the potential of SA403 as a robust PGPR-based tool for sustainable potato production on saline soils.

Rhizosphere↗

PubMed2026

Ecological Restoration of the Soil-Like Function in the Bauxite Residue: Natural Microbiomes Mediated Molecular Transformation of Dissolved Organic Matter.

Soilization of bauxite residues offers a scalable route for long-term carbon management and ecological restoration. However, the microbial processes that transform exogenous organic inputs into stable soil-like carbon pools remain poorly resolved. Here, we combined cross-ecosystem meta-analysis, machine-learning prediction, native synthetic community (SynCom) construction, 13C-labeled straw microcosms, field validation, Fourier transform ion cyclotron resonance mass spectrometry, and genome-resolved metagenomics to unravel microbiome-mediated carbon transformation at the dissolved organic matter (DOM) molecular scale. Our meta-analysis revealed that alkaline industrial wastes retained soil-like DOM signatures but were enriched in microbial humic- and protein-like components, indicating active yet incomplete carbon processing. Guided by these patterns, native SynCom inoculation increased 13C incorporation into total organic carbon (TOC) and dissolved organic carbon (DOC), enlarged biodegradable and adsorbable DOC fractions, and shifted DOM from recalcitrant aromatic pools toward oxygenated carbohydrate-, tannin-, and phenolic-like molecular classes. Genome-resolved analyses linked this transformation to complementary polymer degradation and nutrient-cycling functions across fungal and bacterial guilds, including enriched carbohydrate-active enzymes in straw-carbon-utilizing metagenome-assembled genomes. Null model and thermodynamic analyses further showed that microbial communities were constrained by homogeneous selection, whereas DOM molecules were diversified through variable selection and redox-dependent transformation. Field-scale validation confirmed that SynCom promoted TOC and DOC accumulation and humic-like, high-density DOM fractions under alkaline conditions. Together, these findings establish a mechanistic framework in which functional microbiomes couple plant carbon depolymerization, DOM molecular diversification, and mineral-interactive carbon stabilization, providing a microbiome-guided strategy for carbon sequestration and soilization in the bauxite residue.

Soil↗

PubMed2026

Comparative analysis of DDR-related genes and microRNA expression during rice germination: Implications for salinity susceptibility screening.

Soil salinity poses a significant threat to the agri-food sector and particularly to rice cultivation. High salinity during germination induces overproduction of reactive oxygen species (ROS) that cause lesions in the DNA resulting in reduced vigor. MicroRNAs (miRNAs) are known to modulate stress response in plants, however, studies focusing on its relation with the expression of the DNA damage response (DDR)-related genes are not thoroughly explored. In this regard, the aim of this work was to investigate the link between the expression of miRNAs and putative targeted DDR-related genes in response to salinity stress during germination. Eight varieties representative of indica and japonica rice subspecies were categorized into clusters through a principal component analysis (PCA) based on their germination performance and stress tolerance index under varying concentrations of NaCl. Subsequently, the expression patterns of six miRNAs and their putative targeted DDR genes were measured in two contrastive cultivars through quantitative real-time PCR (qRT-PCR) while correlations were examined through Pearson's analysis. Results showed distinct expression profiles between halotolerant and sensitive cultivars. Two miRNAs were further investigated in mature dry seeds of all the cultivars to verify their earliest, seed-specific discriminative potential. The distinct miR414 expression pattern may represent a potential biomarker for identifying salinity-susceptible cultivars during early-stage breeding screening.

Oryza↗

PubMed2026

Temporal proteomic analysis reveals a three-phase adaptation strategy in Phytophthora cinnamomi during salinity stress.

Phytophthora cinnamomi, a highly invasive hemibiotrophic oomycete, threatens global agriculture, forestry, and native ecosystems. Although drought and temperature effects on P. cinnamomi-host interactions are well studied, current knowledge of abiotic stress responses in P. cinnamomi remains largely centered on infection and phytopathology, with limited molecular insight into the pathogen's direct response to salinity independent of its host. To address this gap, we combined growth assays, time-resolved proteomics, and network analysis to define how P. cinnamomi responds and adapts to salinity exposure. Growth assays showed that NaCl-modified agar enhanced mycelial expansion in a concentration-dependent manner, with 100 mM NaCl significantly increasing growth at 48, 72, and 96 h compared with controls, while 50 mM NaCl remained comparable to control conditions. Temporal proteomic analysis of 100 mM NaCl treatment at 0, 1, 6, 12, and 24 h post treatment revealed dynamic shifts in protein abundance. Early induction of ROS (Reactive Oxygen Species)-detoxifying enzymes, including glutathione S-transferases and peroxidases, was consistent with ROS-specific staining assays. Network analysis identified modules enriched for redox regulation, ATP generation, ion transport, and translational control, highlighting multi-layered adaptation to elevated NaCl levels. Notably, clusters of conserved hypothetical proteins were strongly upregulated, indicating unexplored stress tolerance components in Phytophthora species. Here, we propose that P. cinnamomi rapidly activates a three-phase strategy involving metabolism readjustments, redox defenses, and cellular structure alterations under salinity conditions. With increasing soil salinization due to climate change, our study provides first mechanistic insights into P. cinnamomi's adaptive plasticity and ecological resilience to abiotic stress. SIGNIFICANCE: This study represents the first temporal proteomic analysis of salinity stress adaptation in Phytophthora cinnamomi, revealing a sophisticated three-phase adaptation strategy. This research fundamentally advances our understanding of how this globally destructive plant pathogen, P. cinnamomi, maintains environmental resilience. Our findings reveal proteome remodelling as a mechanistic framework for understanding stress tolerance in oomycetes, a group of microorganisms responsible for some of the world's most destructive agricultural and forest diseases. Our results show proteins involved in emergency damage control through metabolic recalibration to sustained adaptation. These findings have relevance for predicting pathogen behavior under climate change scenarios, where increasing soil salinity threatens agricultural productivity while simultaneously enhancing pathogen survival and virulence. Understanding how P. cinnamomi responds to prolonged salinity exposure may inform targeted biocontrol strategies and improve predictive models of disease pressure in salt-affected agricultural regions. The temporal analysis framework we present offers a broadly applicable approach for understanding microbial stress adaptation, with implications extending beyond plant pathology to environmental microbiology and biotechnology applications where stress tolerance is paramount.

Phytophthora↗

PubMed2026

Comparative phylogenomics and transcriptional regulatory networks of AQPs, HSPs, and LEA proteins in salt-stressed Portulaca oleracea.

Soil salinization severely threatens global food security, necessitating systematic investigations of halophytes like Portulaca oleracea to decode the molecular mechanisms of environmental resilience. Utilizing an integrated framework of deep learning-based genome annotation (58,817 predicted genes; 96.5% BUSCO completeness), multi-tissue RNA-Seq, phylogenomics, and gene regulatory network (GRN) inference, the synergistic orchestration of 78 aquaporins (AQPs), 525 heat shock proteins (HSPs), and 119 late embryogenesis abundant (LEA) proteins was elucidated. The active transcriptome, encompassing 39,065 expressed loci, revealed a systemic growth-defense trade-off. Tissues displayed distinct adaptive mechanisms: leaves modulated intracellular water balance via specialized AQPs, whereas adult roots maintained proteostasis through robust HSP20/HSP70 induction. Phylogenomic clustering across 154 species demonstrated that salinity tolerance constitutes an evolutionary mosaic, identifying 81 halophyte-exclusive orthogroups and 1129 species-specific clusters. Comparative topology across six independent GRNs (4.2M-5.3 M edges) unmasked a highly modular transcriptional reprogramming strategy governed by a core apparatus of 22 stress-exclusive regulators, with functional enrichment heavily prioritizing protein dimerization and chromatin remodeling. Theoretically, the distinct convergence of Trihelix transcription factors with guard cell differentiation pathways offers a candidate transcriptomic framework to explain the plant's characteristic C4-CAM photosynthetic plasticity under severe osmotic pressure. Practically, these evolutionary blueprints and specific master switches transcend single-gene transgenic limitations. Utilizing these root-sustained and stress-inducible targets under localized promoters provides a naturally optimized, network-level precision engineering roadmap to transfer robust, compartmentalized halotolerance to sensitive glycophytic crops.

Gene Regulatory Networks↗

PubMed2026

The effects of nitrate and nitrite supplementation on mitochondrial respiration in permeabilized muscle fibres in young healthy adults.

Nitric oxide (NO) is a direct regulator of mitochondrial respiration. Nitrate (NO3-) and nitrite (NO2-) are good sources of NO, but whether their effects on mitochondrial respiration differ between in vivo and in vitro administration remains unclear. In Study 1, 8 participants consumed NO3- -rich beetroot juice (BR) (∼12.8 mmol NO3-) and NO3- -depleted placebo beetroot juice (PL) (∼0.08 mmol NO3-) acutely and chronically for 2 weeks in a randomised, double-blind, crossover design. A substrate-uncoupler-inhibitor titration (SUIT) protocol was used to assess mitochondrial respiration using high-resolution respirometry (oxygen tension: ∼200-450 μM) in permeabilized muscle fibres. In Study 2, skeletal muscle samples were collected from 11 participants. In a randomised, crossover design, different doses (0, 1.5, and 3.0 μM) of sodium nitrite (NaNO2) were administered to permeabilized muscle fibres. Mitochondrial respiration was measured using the same SUIT protocol under lower oxygen tension (∼50-200 μM). Although muscle NO3- concentration significantly increased after both acute and chronic BR supplementation, mitochondrial respiration and exercise performance did not differ between PL and BR in either condition. Similarly, absolute oxygen flux across different respiratory states were not different between different doses of NaNO2. However, the leak control ratio, reflecting the degree of uncoupling of mitochondrial respiration, was significantly higher with 3.0 μM NaNO2 administration (0.12 ± 0.05) compared to 0 μM NaNO2 administration (0.09 ± 0.04, P = 0.03). These findings, involving both in vivo and in vitro administration approaches, albeit in the presence of relatively high oxygen concentrations, suggest that neither NO3- nor NO2- improves mitochondrial respiration, at least in young healthy adults.

Humans↗

PubMed2026

Littoral and wetland vegetation decrease carbon emissions from dry inland waters.

Lakes are recognized as active components of the inland water carbon (C) cycle, as organic matter is processed by microbial respiration, inducing large carbon dioxide (CO2) and methane (CH4) emissions. In the context of long-lasting drought periods, large uncertainties remain about: (1) the influence of wet-dry cycle on CO2 and CH4 fluxes in littoral zones and lacustrine wetlands; and (2) the contribution of emergent vegetation to C fluxes in dry inland waters. At the water-land interface of two shallow lakes, this study focuses on CO2 and CH4 fluxes from vegetated and bare dry inland waters in relation to hydrological fluctuations. Three seasonal campaigns were conducted to measure daytime CO2 and CH4 fluxes in pelagic, littoral and wetland surface waters, as well as in temporarily air-exposed sediments, using floating and static chambers, respectively. Our results reveal that wet-dry cycle in the littoral zone and wetlands strongly influence gaseous C fluxes through contrasting patterns, especially in late summer, when the biological processes are most active (primary production and respiration). In air-exposed littoral zones, organic-poor sandy sediments presented the lowest CO2 and CH4 emissions, whereas in air-exposed lacustrine wetlands, water-saturated sediments accumulated high amounts of plant-derived organic matter, promoting intense microbial activity and the highest C emissions. However, amphiphytes and helophytes vegetation in exposed littoral zones and wetlands reversed the direction of C fluxes, inducing the highest CO2 uptake due to high photosynthesis rates. This study underlines the relevance of considering vegetation in dry inland waters, particularly in lacustrine littoral zones and wetlands, to obtain comprehensive lake C budgets, especially under climate change scenarios.

Wetlands↗

PubMed2025

Influence of soil types with different soil-forming process on the qualitative and quantitative detection of microplastics by near-infrared spectroscopy.

Microplastics (MPs) have become a pressing global environmental threat, with soils-acting as sinks for MPs from multiple sources-gaining increasing attention. Near-infrared (NIR) spectroscopy offers a promising tool for MPs detection due to its rapid, non-destructive, and field-applicable features. Although previous studies have focused on the effects of individual soil components on the NIR detection performance of MPs, there is still a lack of systematic research on how the complex background-formed by the coupling of multiple physicochemical properties in natural soils-affects detection performance. This study focuses on soil types with different soil-forming processes, selected five representative agricultural soils to systematically evaluate how the combinations of physicochemical properties they represented affect the performance of NIR-based qualitative and quantitative analysis of MPs in soils. The results demonstrated that soil type significantly affected both the spectral response and detection performance of MPs. Brown Pedocals and Brown Earth exhibited clearer characteristic absorption and stronger linear responses, achieving higher identification accuracy under low (<1.5 %) or zero MPs concentrations and the best quantitative performance (R2 ≥ 0.988, prediction set root mean square error (RMSEP) ≤ 0.110 %). In contrast, Phaeozem and Red Soil were more prone to misclassification at low concentrations, while Fluvo-aquic Soil showed the poorest quantitative performance. This study is the first to reveal, at a holistic level, the critical constraints posed by natural soil complexity on the NIR detection of MPs, offering targeted empirical evidence to support the application of NIR technology in real-world soil environments.

Soil↗

PubMed2025

New insights into soil amendment: Impact of humic acid on typical antibiotic resistance in agricultural soil.

Humic acid (HA) addition can improve agricultural soil, but little is known about how it affects the soil resistome. In this study, we used selective agar plate combined with quantitative PCR (qPCR) and 16S rRNA gene sequencing to investigate how HA influences antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs) in soil contaminated with erythromycin and kanamycin. 0.1 % HA reduced the abundance of culturable erythromycin-resistant bacteria (ERB), while promoting the growth of kanamycin-resistant bacteria (KRB). Lysinibacillus and Paenibacillus were the dominant genera in ERB and KRB, respectively, governing the changes in their abundances. At this concentration, the Lysinibacillus abundance in ERB decreased from 96.74 % to 70.57 %. Meanwhile, that of Paenibacillus in KRB increased from 33.40 % to 77.44 %. The copy number of ermF decreased after HA addition, while that of ermB increased. Furthermore, 0.1 % HA significantly reduced the copy number and relative abundance of aadA1 and aac(6')-Ib (aka aacA4)-03 in the soil. Changes in these two types of ARB and ARGs were primarily driven by shifts in the microbial community structure. Soil physicochemical properties, particularly increased organic matter (OM), altered the absolute abundance of ermB. Meanwhile, changes in intI1 abundance determined the risk associated with aadA1 and aac(6')-Ib (aka aacA4)-03. These findings emphasize the dual role of HA in the dissemination of antibiotic resistance in agricultural soils and highlight the necessity of considering dose-dependent effects when applying HA as a soil amendment.

Soil Microbiology↗

PubMed2026

Electron shuttles facilitate methane-dependent arsenate reduction in paddy soils.

Methane-dependent arsenate reduction (M-AsR) occurs widely in paddy soils and can substantially enhance arsenic mobilization, posing potential ecological risks. However, the role of electron shuttles in this process remains poorly understood. In this study, we investigated the influence of anthraquinone-2,6-disulfonate (AQDS) on M-AsR in paddy soils. Fourteen-day incubation showed that 1 mmol/L AQDS facilitated 50.88 % of arsenate reduction and 31.31 % of methane oxidation. Quantitative polymerase chain reaction analysis revealed that AQDS significantly increased the abundance of functional genes associated with arsenate reduction (arrA, arsC) and anaerobic methane oxidation (mcrA) (P < 0.05). Microbial community analysis revealed that AQDS addition enriched Cloacibacterium, Sphingorhabdus, and Methylocystis, while decreasing the relative abundance of Methylobacter and Methylomonas. These findings indicate that electron shuttles facilitate M-AsR by modulating functional microbial populations, providing valuable insights into arsenic biogeochemistry and the coupled cycling of methane and arsenic in paddy soils.

Methane↗

PubMed2026

Meta-analysis of source identification and apportionment in soil: A systematic review of analytical procedures, receptor modeling, and environmental applications.

Soil pollution poses significant risks to ecosystems and human health, necessitating accurate source identification and apportionment to guide mitigation strategies. This systematic review evaluates the application of Positive Matrix Factorization (PMF) and other receptor models in soil pollution studies, focusing on analytical procedures, tracer indicators, and environmental applications. This review aims to provide a comprehensive framework for conducting soil source apportionment studies, aiding policymakers in designing effective, region-specific environmental management strategies by compiling global trends and methodological insights. The study addresses sampling protocols, emphasizing representativeness and quality control. Data from 500 peer-reviewed publications highlight the dominance of research in China, Eastern Europe, and South Asia, with agricultural soils being the most frequently studied. Key findings reveal that traffic emissions (20.8 %) and industrial activities (19.4 %) are the primary global contributors to soil contamination, with regional variations such as coal combustion in cold climates and agricultural inputs in developing regions. Policy recommendations include stricter industrial regulations, sustainable agricultural practices, and targeted remediation efforts based on source-specific risks.

Soil Pollutants↗

PubMed2026

Watershed-scale risk assessment of cadmium contamination in Chinese cropland soils: Dual pathways of irrigation input and flood-driven transport.

Irrigation and flood events serve as critical pathways for the transport of cadmium (Cd) from industrial sources into cropland soils at the watershed scale, constituting a major driver of widespread Cd contamination in China's cropland soil. This study evaluated the risk of Cd contamination in cropland soils across China's nine major river basins at the watershed scale, focusing on the contributions of irrigation and flood events, and conducted a sensitivity analysis of key risk factors. The assessment was conducted within a framework that considered factors including hazard, exposure, and vulnerability. The results revealed that numerous watersheds in southeastern China are exposed to dual pressures of Cd contamination risks in cropland soils, driven by both irrigation practices and flood events. Watersheds categorized as High-High, High-Moderate, or Moderate-High risk, reflecting combined Cd contamination risks from irrigation and flood, are vital to China's grain production, contributing 67.1 % of the national cropland area and 66.4 % of the grain yield. The study suggests localized strategies for managing cropland soils Cd contamination risks from irrigation and flood at the watershed scale in China, alongside strengthened cross-regional collaboration in southeastern China.

Cadmium↗

PubMed2026

Formation of environmental persistent free radicals in soil of ammunition demolition site: Roles of 2,4,6-trinitrotoluene and heavy metals.

Environmental Persistent Free Radicals (EPFRs) are a particular type of contaminant present in soil. This study investigated the formation process, environmental behavior, and main influencing variables of EPFRs in soils contaminated with heavy metals and 2,4,6-trinitrotoluene (TNT) from an ammunition demolition site. The results showed that the concentration of total organic carbon (TOC) in the soil was negatively correlated with EPFRs (r = -0.29). In contrast, the content of TNT and copper was significantly positively correlated with EPFRs (r = 0.90 and 0.78, respectively), indicating that TNT acts as a precursor macromolecule in the formation of EPFRs in this type of contaminated soil. Transition metal Cu may be an essential carrier in EPFR production. In order to explore the possible formation mechanism of EPFRs, a simulation experiment was carried out under different temperature and light conditions. The results showed that the photolysis process of TNT was impacted by external energy sources such as heat and light. TNT was firstly adsorbed onto the surface of a transition metal (Cu), and then EPFRs were formed through further electron transfer. This is the first study to detect significant levels of EPFRs in the soil at ammunition demolition sites.

Trinitrotoluene↗