Search Results (1,251)

Agricultural soil contamination by potentially toxic elements is a global concern due to its impacts on food safety and human health, yet comprehensive assessments remain limited in many regions of Ethiopia. This study provides an integrated assessment of PTE contamination in agricultural soils of the North Gondar Zone, Ethiopia, by evaluating physicochemical properties, pollution levels, and human health risks. Soil parameters, including pH, electrical conductivity, organic carbon, organic matter, moisture content, total nitrogen, and available phosphorus, varied among sampling sites. Soil pH ranged from moderately acidic to near-neutral, indicating variations in soil acidity likely associated with differences in moisture content, organic matter, and land management practices, while electrical conductivity values indicated non-saline conditions suitable for agriculture. Concentrations of PTEs (As, Zn, Cd, Pb, and Hg) were generally within permissible limits established by WHO and FAO. Pollution indices revealed predominantly natural background levels for As, Zn, Cd, and Pb, whereas Hg exhibited moderate to strong contamination, with the Geoaccumulation Index and Contamination Factor identifying Hg as the primary environmental risk element. Non-carcinogenic risk assessment showed that hazard quotients and hazard indices for both adults and children were below 1, indicating negligible health risks. Carcinogenic risk assessment demonstrated that all calculated risks were within the acceptable range (10⁻⁶–10⁻⁴), although children showed higher total cancer risk (TCR) values than adults due to greater exposure intensity and lower body weight. Arsenic was identified as the dominant contributor to carcinogenic risk across all sampling sites. The findings demonstrate that agricultural soils in the study area are generally safe with respect to the investigated PTEs; however, Hg contamination indices indicate a potential environmental concern requiring continued monitoring. Sustainable soil management practices, including effective pH management and liming of strongly acidic soils (pH < 5.5), are recommended to improve soil quality, reduce PTE mobility and bioavailability, and minimize future accumulation of hazardous elements while maintaining agricultural productivity. Full article

Rapid accumulation of soil lanthanum (La), cerium (Ce), and fluorine (F) caused by bastnasite mining development has increasingly become a concern worldwide in the past decades. However, the effects of the different chemical forms of these elements on the composition and diversity of soil dominant, moderate, and rare microorganisms are unclear. In this study, Planctomycetota was changed from dominant to moderate, caused by exchangeable and carbonate-bound forms of La and Ce. Both organic bound La (La_ORG) and water-soluble F (F_WS) were the crucial factors driving variations in the relative abundance of Patescibacteria and Bacteroidota from moderate to dominant, while the fungal phylum Chytridiomycota was changed from moderate to dominant, promoted by F_WS. La_ORG, the ferrum-manganese bound form of Ce, and F_WS displayed a negative correlation with the three rare bacterial phyla, i.e., Abditibacteriota, GAL15, and Deinococcota respectively. F_WS caused the disappearance of the rare fungal phylum Monoblepharomycota and the appearance of the rare bacterial phylum Fibrobacterota. Organic bound forms of both Ce and F showed a negative correlation with the bacterial Sobs and fungal Phylogenetic diversity indices, respectively. To summarize, the different chemical forms of La, Ce, and F showed varied effects on the composition and diversity of soil microbial communities. Full article

Phenolic acids are considered important allelochemicals that can restrict nutrient uptake and inhibit plant growth. Most existing studies have focused on growth phenotypes and single nutrient changes under phenolic acid stress, while the coupled C:N:P balance responses of plant–soil systems remain poorly characterized. Ecological stoichiometry offers a holistic perspective to reveal the nutrient supply–demand mismatch underlying allelopathic inhibition by analyzing elemental ratio dynamics, thus deepening the mechanistic understanding of allelopathy beyond traditional single-indicator observations. Using lettuce (Lactuca sativa L.) as the test plant, this study investigated the effects of cinnamic acid (CA) and p-hydroxybenzoic acid (PHA) stress, combined with nitrogen (N), phosphorus (P), and their combined application (NP) on plant growth and plant C, N, and P stoichiometric characteristics. Soil C, N, and P contents and stoichiometric characteristics were further analyzed as supplementary indicators. The results showed that phenolic acid stress significantly reduced lettuce biomass: PHA decreased aboveground biomass by 40.11% and belowground biomass by 44.14%, with a stronger inhibitory effect than CA. Both phenolic acids induced marked stoichiometric imbalance, characterized primarily by a sharp decline in leaf nitrogen content; N content dropped by 49.80% under CA and 70.75% under PHA, corresponding to a 64.43% and 162.79% increase in leaf C:N ratio, and a 37.63% and 63.19% decrease in leaf N:P ratio, respectively. Nutrient addition alleviated these responses to varying degrees: N addition mainly promoted biomass recovery and elevated plant N status, P addition optimized elemental ratios, and combined NP application yielded the strongest overall recovery. Correlation and redundancy analyses indicated that soil C, N, and P stoichiometric characteristics were closely associated with plant growth, with soil organic carbon and total phosphorus identified as major explanatory variables associated with plant growth. Overall, phenolic acid stress altered plant stoichiometric characteristics and growth, as well as soil C, N, and P stoichiometric characteristics, while nutrient addition partially alleviated these responses. These findings provide a stoichiometric perspective for understanding allelopathic stress and may offer a theoretical basis for nutrient management under continuous cropping conditions. Full article

Microplastics (MP) are emerging pollutants found in the Veracruz Reef System National Park (PNSAV). They are widely distributed in the aquatic environment and are ingested by organisms either accidentally or because they are mistaken for food. In this article, the author analyses the physicochemical characteristics of reef sediments using visual identification, Nile Red (NR), scanning electron microscopy (SEM), and Energy Dispersive Spectroscopy (EDS) of microplastics found in sediments adjacent to reefs; this allowed us to determine their distribution within the PNSAV. A total of 687 microplastics per kilogram of dry sediment were quantified, including fibres (98.5%), films (1.4%), and fragments (0.01%). The predominant colour was transparent (60.2%), followed by blue (16%) and red (12%). Based on their MP distribution, the sites were classified into two groups: north and south. The sampling stations with the highest concentrations of MP are located in the group of reefs south of the PNSAV, with the Anegadilla Reef being the most affected station. SEM/EDS analyses revealed elemental spectra dominated by carbon and oxygen, which is consistent with the expected elemental composition of polymeric materials. Peaks of chlorine were detected in some MP particles, suggesting the possible presence of chlorinated polymers, such as polyvinyl chloride (PVC). In addition, elements such as titanium, silicon, and nickel were identified, which could be associated with inorganic particles adhering to the surface or with additives commonly incorporated during the manufacture of plastics such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), and polyethylene terephthalate (PET). The presence of elements such as titanium and nickel were detected; these are found in additives used in the manufacturing of polymers. Full article

To clarify the composition and origin of the suspected solid bitumen, which is found in the fractures of the Jixian System in Tongcheng outcrops, the suspected solid bitumen samples, as well as dolomite samples, were collected from the Jixian System in Tongcheng and Qishan outcrops for various tests. The results show that the suspected solid bitumen samples are mainly composed of clay minerals. No solid bitumen was found in the pores and microcracks of the dolomite samples by microscope and Raman spectroscopy. The total organic carbon content of the solid bitumen ranges from 0.59% to 1.15%, revealing that the suspected solid bitumen is dark mudstone powder, rather than solid bitumen. The R_b values range from 2.59% to 2.77%, and the Ts/(Ts + Tm) values mostly approach 0.5, indicating that the organic matter in the suspected solid bitumen is in the mature to over-mature stage. The V/(V + Ni), Sr/Cu, and Sr/Ba values of the suspected solid bitumen indicate that it was deposited in a warm, humid, anoxic sedimentary environment. The slightly right-inclined rare earth element pattern of the suspected solid bitumen samples implies the sedimentation rate was slow or they were affected by weathering and leaching processes. Through a comparison of trace elements and hierarchical clustering analysis of rare earth elements, the suspected solid bitumen manifests the closest correlation with the mudstone source rocks of the Cambrian Zhangxia Formation. Early Devonian period, the Cambrian mudstone source rocks in the Tongcheng area were uplifted; then weathered, leached, and fragmented into powder; and then filled the fractures of the underlying Mesoproterozoic Jixian System. Of course, another geological scenario has not been ruled out: that some of the fractures in the Jixian System may be filled with solid bitumen, which may be the result of the destroyed paleo-oil reservoirs near the ancient uplift in the Tongcheng area. Full article

Although the health risks associated with the use of biomass fuels have received widespread attention, there has been insufficient detailed research conducted on the toxic effects and toxicity generation mechanisms of PM_2.5 produced by the use of different sources of solid organic fuels. In this study, the synchronized L4-stage Caenorhabditis elegans (C. elegans) were exposed to the suspensions of the PM_2.5 samples collected from incomplete combustion products of rice straw, wheat straw, peanut straw, rapeseed straw and the branch of poplar and paulownia. Body length, the number of fertilized eggs, accumulation of lipofuscin, and levels of reactive oxygen species (ROSs) were measured to characterize developmental toxicity, reproductive toxicity, intestinal damage, and oxidative stress. The types and mass proportions of organic carbon (OC), elemental carbon (EC), water-soluble inorganic ions, and polycyclic aromatic hydrocarbons (PAHs) in PM_2.5 were determined. The results show that PM_2.5 generated from the combustion of the straw of oilseed crops such as peanuts and rapeseed has the most severe toxic effects on C. elegans. The toxicological mechanism was mainly mediated by severe oxidative stress and excessive generation of ROSs. The chemical characteristics of PM_2.5 have strong source-specificity, and its toxic effects are closely related to the high content of lipid-soluble PAHs in PM_2.5 from oilseed crop sources. Full article

This work reports, for the first time, the use of agave bagasse from “Tequila Weber Var” as an efficient and eco-friendly template for the microwave-assisted solvothermal synthesis of C@TiO₂ photoelectrodes. The characterization of the C@TiO₂ materials was performed using composition and elemental analysis, diffuse reflectance/UV-visible spectroscopy, N₂ adsorption/desorption isotherms, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction patterns, cyclic voltammetry, impedance spectroscopy, and variations of the open-circuit potential in a conventional electrochemical cell. Three 1:1, 4:1, and 8:1 agave:Ti volume ratios were used to explore the influence of carbon content upon the optical and photoelectric properties of TiO₂. The composite with a 1:1 ratio showed a charge transfer kinetic capacity of 0.86 C·cm⁻²·s⁻¹ with the highest current density flow of 2.2 mA·cm⁻², and the lowest optical band gap (E_bg) value of 2.92 eV, boosting the optoelectronic behavior of TiO₂. The photoanode composed of FTO/C@TiO₂ with the hybrid material with a 1:1 ratio was preliminarily evaluated in a photovoltaic solar cell, showing a light-to-electricity conversion efficiency higher than the other two composites and up to 12.5 times higher than the photoanode only composed of neat TiO₂. The present results contribute to the state-of-the-art of eco-friendly organic–inorganic thin film photoelectrodes for the sustainable synthesis of third-generation solar cells using bagasse-derived waste as an efficient carbon source for the synthesis of hybrid photoactive semiconductors. Full article

The growing demand for efficient and sustainable materials for air purification has stimulated interest in activated carbons derived from renewable biomass resources. In this study, activated carbons were prepared from Rice Husk, Wheat Straw, Sawdust, and Walnut shells and systematically investigated as sorbents for toxic gases and volatile organic compounds. The materials were characterized using nitrogen and water vapor sorption isotherms, scanning electron microscopy, thermogravimetric analysis, Fourier-transform infrared spectroscopy, energy-dispersive X-ray and XPS analysis to evaluate their textural properties, morphology, thermal stability, and surface chemistry. The results showed that the precursor type strongly influences the pore structure and functional group composition of the activated carbons. Wheat straw and Rice Husk-derived activated carbons exhibited the highest total pore volume and a well-developed porous structure, together with a high content of oxygen- and silicon-containing elements. Gas breakthrough experiments with different probes showed that Wheat Straw-derived activated carbon excels in non-polar VOC—cyclohexane removal due to its highly microporous structure. In contrast, Rice Husk-derived activated carbon displays strong affinity toward inorganic gases such as NH₃ and, after urea modification, achieves enhanced performance for SO₂. These results underscore the versatility and practical applicability of carbon materials obtained from plant residues. Full article

Pure ZnO and ZnO/Gd₂O₃ (1 and 2 mol %) nanoneedles were synthesized via a sonochemical route and evaluated as catalytic materials for the degradation of paracetamol using glass and PTFE (Teflon) stirring rods. The morphology and elemental composition of the obtained nanostructures were investigated by SEM and EDS analyses, confirming the formation of anisotropic rod-like architectures and the successful incorporation of gadolinium species into the ZnO matrix. The optical and defect-related properties were further examined by photoluminescence and UV–Vis spectroscopy, revealing defect-related modifications in the electronic structure and improved charge carrier behavior in the gadolinium-modified samples. Comparative catalytic experiments showed higher degradation efficiencies in the system employing the glass stirring bar compared to the PTFE. However, the differences between these two setups are not limited solely to the stirring bar material, but also involve variations in interfacial contact conditions during operation. Therefore, the observed differences in catalytic activity cannot be attributed to a single mechanistic origin such as mechanically induced effects, but rather reflect the combined influence of catalyst–surface interactions and the specific nature of the stirring medium. The influence of inorganic ions on paracetamol degradation was also investigated using distilled water and aqueous solutions containing sodium chloride, sodium sulfate, and sodium hydrogen carbonate. In both systems, the ZnO/Gd₂O₃ samples exhibited higher degradation efficiency than pristine ZnO, indicating that Gd incorporation plays a key role in enhancing catalytic performance. This improvement can be associated with a modified defect structure and more favorable charge carrier dynamics in the doped material. The mineralization efficiency of the treated solutions was additionally evaluated through chemical oxygen demand (COD) measurements, confirming a significant reduction in organic load after treatment. Full article

Silicon is among the most abundant elements on Earth, yet its incorporation into organic molecules is atypical in most biological contexts. However, the strategic introduction of silicon, in line with the demonstrated success of the incorporation of other bio-orthogonal elements, has emerged as a powerful approach in medicinal chemistry, enabling access to small molecules with unique chemical, physical, and biological properties that offer improved potency, stability, tolerability, or bioavailability profiles for the discovery and development of anticancer therapeutics. In this review, we describe the direct connection between reactivity and physiochemical paradigms of different classes of organosilicon-containing functional groups and their strategic deployment in small molecule design, including silanes, silyl ethers, siloxanes, and organosilicates. Specifically, we aimed to demonstrate how these strategies can be informed by first principles of reactivity in organosilicon containing functional groups, in both synthetic small molecules and bioactive natural products. Particular emphasis is placed on how silicon replacement and addition can be leveraged beyond simple isosteric carbon replacement, and how consequent structure–activity relationships arising from installation of diverse organosilicon motifs can also serve a unique role in unveiling new aspects of biological mechanism and function. Ultimately, the growing body of literature in applications of organosilicon-containing anticancer small molecules and the increasing sophistication and selectivity of synthetic methods used to construct these motifs will undoubtedly continue to expand the appreciation of organosilicon-based functional groups in the medicinal chemist’s toolbox. Full article

Background: Collagen-based scaffolds are widely used in regenerative applications, where their structural organization and physicochemical stability are essential for clinical performance. This study aimed to evaluate the influence of hydration on the thermal behavior and microstructural characteristics of a collagen-based matrix (Mucoderm^®, Botiss Biomaterial GmbH, Zossen-Germany). Methods: Differential scanning calorimetry (DSC) was used to investigate thermal transitions in dry and rehydrated samples, while scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) was employed to assess surface morphology and elemental composition; Results: The dry sample exhibited a broad endothermic transition at 87.8 °C, which shifted to higher temperatures upon rehydration, reaching 103.5 °C and 112.4 °C after 15 and 30 min, respectively. A corresponding increase in enthalpy values was also observed. SEM analysis revealed a heterogeneous surface morphology characterized by alternating compact and less dense regions, while EDS confirmed the predominance of carbon and oxygen with minor elements present in trace amounts; Conclusions: These findings indicate that hydration influences both the thermal response and structural organization of the scaffold, highlighting the role of water–matrix interactions in determining its physicochemical behavior. Full article

This work describes a method to create submarine artificial structures based on light metallic structures covered by calcareous layers obtained by electrolysis in sea water, with full environmental safety of the process. For structures based on meshes of cylindrical steel wire, the thickness of the deposited layer increases linearly with time for widths up to 2 mm. In the case of thicker layers, mathematical modelization suggests that the evolution of the deposited layer width might not be linear. Under the experimental conditions of this work, the deposited layers were mainly composed of stable crystalline forms of calcium carbonate. No significant presence of magnesium containing minerals was found in the deposited layers. The composition and texture of the obtained surfaces might be deemed as optimum from the point of view of providing colonization sites for the sessile benthic organisms of interest. These structures may be used as elements that can be included in the design of environmental remediation applications. Regarding their potential applications, once deployed in the marine environment and colonized by sessile benthic filter-feeding species, the structures could contribute to the improvement of sea water quality in commercial ports or marinas, which might be affected by organic pollution. Full article

Karst rocky desertification (KRD) is a critical abiotic stressor that compromises Rosa roxburghii Tratt fruit quality, yet its underlying physiological and ecological pathways remain poorly understood. This study aims to bridge this knowledge gap by elucidating how KRD-driven soil C:N:P:K stoichiometric shifts indirectly affect fruit quality (vitamin C and fructose) by disrupting fruit internal elemental balance. We characterized soil nutrient dynamics and evaluated fruit quality along the natural rocky desertification gradient (RDG) in Guizhou, China. Mantel tests and structural equation modeling (SEM) were applied to identify primary predictors and quantify integrated pathways. With increasing desertification, total organic carbon (TOC), total nitrogen (TN), and soil C:P ratio (C:P) increased monotonically, while total phosphorus (TP) remained at a low concentration without significant change. Available phosphorus (AP) and available potassium (AK) followed a U-shaped trend, reaching their minimum under moderate desertification, whereas total potassium (TK) peaked at this stage before declining. Correspondingly, fruit vitamin C (FVC) and fruit fructose (FF) exhibited a non-linear pattern, first increasing under light stress, then decreasing under moderate stress, and finally rebounding under severe desertification, which is consistent with the nonlinear response pattern of fruit C:P ratio (FC:FP) reported for the same desertification stages. The SEM revealed a dual-pathway mechanism: KRD directly enhanced FVC (β = 0.69, p < 0.001), while KRD and soil properties enhanced FF (β = 0.39 and 0.64, respectively, p < 0.01). KRD also indirectly lowered FVC and FF through a sequential nutrient cascade that promoted soil nutrients (Soil, β = 0.81–0.82, p < 0.001), which triggered negative effects particularly via soil stoichiometry (SS, |β| = 0.76–0.91, p < 0.001), with a modest additional contribution from fruit stoichiometry (FS, |β| ≈ 0.27, p < 0.05). This suggests that KRD influences fruit quality via a soil–plant network mediated by soil P-limitation and K-dynamics. Balanced P and K management may, therefore, be critical for maintaining fruit quality and ecological restoration in karst ecosystems. Full article

This manuscript will present an advancement of transformative research that has been conducted at Oak Ridge National Laboratory (ORNL) over a 25-year period (2000–2025) on a variety of environmental and biological matrices. These investigations derived a fundamental understanding of how elemental detection and analysis of these matrices led to the knowledge and discovery of natural processes in plants and the environment. Each project led to the initiation of a new research area which unearthed awesome and novel breakthroughs. Highlights are listed below: 1. The preliminary research at ORNL centered on the detection of aerosols utilizing Laser-induced Breakdown Spectroscopy (LIBS) technology. The Clean Air Act Amendment (CAAA) of 1990 highlighted the importance of identifying hazardous air pollutants (HAPs) due to their impact on environmental and human health, thereby underscoring the need to detect various toxic elements. Research in aerosol chemistry aimed to identify these harmful elements released by factories during periods of increased emissions in their manufacturing processes. LIBS emerged as the most effective method for real-time, in situ measurements of metal species in both gaseous and aerosol phases. 2. An understanding of the presence of total carbon in soils gives perspective on how to develop carbon sequestration strategies. The recognition that carbon sinks can evolve back to carbon sources to emit back to the atmosphere was an important consideration. Also, the concentration of carbon in soil indicates the health of land areas for growing crops successfully. 3. The direct detection of most of the elements in a wood sample in a single emission spectrum, without sample preparation, encouraged the research to use the LIBS technique for preservative treated wood coupled with use of multivariate statistical methodology. Additionally, it encouraged the researchers to try to differentiate natural woods from different parts of the country, and it was successfully demonstrated that LIBS coupled with MVA analysis could differentiate wood of different species from each other and of similar species grown in different environments based on their elemental spectra. This was a breakthrough since it revealed a systematic approach to connect elemental scarcity and abundance to either drought or typical rainfall conditions for the hardwood trees grown in specific areas. 4. Furthermore, the research progressed to reveal physiological and developmental processes contributing to biomass production such that the variation in leaf elemental composition increases our understanding of terrestrial nutrient cycles, as well as tracking the transfer of toxic elements from soils to living organisms. 5. Recently another breakthrough viz., ionomics initiated the correlation of elements to specific genes, uncovering the function that the element performed in the plant. More recently, this has been extended from plants to fungi as well as fungi growing in symbiotic relations with plants. Full article

Karst terrains hold vital global groundwater reserves, underpinning regional water security and ecological stability. To elucidate groundwater hydrochemical patterns and formation mechanisms in Wuhan’s karst zone, this study adopted the Gibbs model, correlation analysis, principal component analysis and positive matrix factorization to explore water–rock interactions, hydrochemical origins, element migration, hydrogeochemical facies and genetic processes. The results show that water in both confined porous loose rock aquifers (CPLRAs) and karst fissure carbonate rock aquifers (KFCRAs) is mainly of HCO₃–Ca and HCO₃·SO₄–Ca types. Carbonate dissolution dominates hydrochemical evolution, with Ca²⁺, Mg²⁺, and HCO₃⁻ as major ions. Natural water–rock interactions control the ionic characteristics of both groundwater types. Silicate weathering exerts a greater influence on water in the KFCRA, while water in the CPLRA has more complex ion sources. Anthropogenic activities contribute 17.52% and 17.61% to their hydrochemical variations, suggesting moderate human influence. Water in the CPLRA is mainly affected by domestic sewage and soil organic nitrogen, locally superimposed with industrial and mining disturbances. Water in the KFCRA is primarily influenced by agricultural pollution, with minor domestic sewage input. These findings provide a scientific basis for sustainable development, protection, and targeted pollution control of groundwater resources in the Wuhan karst area, and offer a reference for hydrochemical studies in comparable karst regions. Full article