Soybean urease-induced calcium carbonate precipitation (SICP) is an innovative and eco-friendly approach with demonstrated potential for mitigating soil liquefaction. However, the specific impacts of the concentrations of soybean urease and salt solutions require further elucidation. The research examines how the two compositions influence calcium carbonate formation. Dynamic characteristics of one-cycle SICP-treated clean and silty sand were analyzed based on cyclic triaxial tests. It was revealed that SICP-treated specimens of both liquefied sand and silty sand exhibit reduced accumulation of excess pore pressure and diminished strain growth under cyclic loading, thereby delaying liquefaction failure. Although higher concentrations of both soybean urease and salt solution can enhance liquefaction resistance, salt solution concentration has a more pronounced effect on improving liquefaction resistance due to the more production of calcium carbonate. Scanning electron microscopy observations confirmed the presence of calcium carbonate crystals at the interfaces between sand particles and between sand and fine particles. These crystals effectively bond the loose sand and fine particles into a cohesive matrix, reinforcing soil structure. A direct linear correlation was established between the liquefaction resistance improvement and precipitated calcium carbonate content. Notably, the one-cycle SICP treatment method adopted in this study demonstrates a better biocementation effect compared to cement mortar or multi-cycle MICP-treated sand under the same content of cementitious materials. These findings provide valuable insights for optimizing SICP treatments, aiming to reduce the risk of soil liquefaction in potential field applications.

With the continuous impact of human activities on the ecological environment, buprofezin and cadmium are frequently detected in soil, sediment, and aquatic environments, posing ecological risks to non-target aquatic organisms. However, limited research exists on the toxic effects and mechanisms of action of these pollutants on aquatic organisms. This study used Xenopus laevis tadpoles as model organisms to experiment with buprofezin and cadmium. Through biochemical parameters and multi omics analysis methods, the single and combined toxicity mechanisms were explored. The experiment used environmentally relevant exposure levels to monitor the growth indicators, movement parameters, oxidative stress biomarkers of tadpoles, and conducted metabolomics and transcriptomics analysis. The results indicate that cadmium inhibits the growth of tadpoles, leading to a decrease in weight, and mixed exposure has a similar effect. Under dark conditions, buprofezin and cadmium significantly alter the swimming behavior of tadpoles, decreasing distance and average speed. Moreover, tadpoles exposed to buprofezin and cadmium experienced oxidative stress, which was reflected in increased levels of malondialdehyde and decreased activities of superoxide dismutase and glutathione S-transferase. Metabolomics and transcriptomics results showed that the combined exposure group produced more differentially accumulated metabolites and differentially expressed genes than the single exposure group. These genes and substances mainly affect the energy metabolism and signal transduction processes of tadpoles. In summary, buprofezin and cadmium interfere with gene expression and alter metabolite levels in tadpoles. This study reveals the combined toxicity of buprofezin and cadmium at environmentally relevant exposure levels. The research results provide toxicological evidence for the risk assessment of environmental pollutants and offer new insights into the effects of complex mixtures.

Lead (Pb) is among the most toxic heavy metals in biological systems and causes toxicity from seed germination to yield formation. High Pb concentrations lead to oxidative damage and impair water relation and nutrition uptake in plants. Rye (Secale cereale L.) is an abiotic stress-tolerant crop, distributed in Eastern and Central Europe. Pb concentration in soils higher than 30 mg kg-1 is commonly toxic to plants. This study investigated the effects of different Pb concentrations [0, 100, 200 and 400 mu M of Pb(NO3)2] on mineral element concentrations (B, Ca, Cu, Fe, K, Mg, Mn, Na and Zn) in rye plants. After 15 days of Pb stress, the levels of mineral elements (B, Ca, Cu, Fe, K, Mg, Zn, Mn and Na), and Pb accumulation were detected using by ICP-OES (Inductively coupled plasma-optical emission spectrometry) in leaves and roots. Under 0, 100, 200 and 400 mu M Pb application, the Pb accumulation varied between 0.005-2.94 and 5.63-13.63 mg kg-1 in leaves, and 0.03-69.34-168.11-329.74 mg kg-1 in roots, respectively. Roots accumulated higher levels of Pb than the leaves. The amounts of Na, Fe and B concentrations reduced, whereas the contents of Ca, K, Mn, Cu, and Zn increased in both leaves and roots in a concentration-dependent manner. The maximum rate of increase or decrease in elemental contents was recorded for 400 mu M Pb-exposed plants. In addition, Mg content increased in leaves, but decreased in roots. Overall, our findings suggest that Pb-exposure causes alterations in mineral element concentrations in a concentration-dependent manner, which could be useful to make risk assessments for Pb pollution in agricultural lands.

The subject of the current paper is the dynamic behaviour of anisotropic half-plane with surface relief containing a flexible or rigid foundation and two buried lined or unlined tunnels under time-harmonic waves radiated via embedded line source. The aim is to anticipate the influence of different model key factors such as (a) the soil topography; (b) the soil anisotropy; and (c) the soil-tunnels and soil-foundation-tunnels interaction. The computational tool is the direct boundary element method (BEM) based on the frequency-dependent fundamental solution for 2D general anisotropic solid derived by the Radon transform. The lined tunnels are implemented in the numerical model by the sub-structuring approach, which allows an efficient numerical processing of integrals along the interface boundaries. Numerical scheme verification and parametric studies are performed, and respective concluding remarks are summarized. The obtained results clearly illustrate the dynamic response sensitivity to the soil anisotropy, the soil topography and the complex soil-foundation-tunnels interaction.

Global warming subjects soil organisms to elevated temperature stress, while simultaneously altering the detoxification processes for pollutants within these organisms. The combined stressors of increased temperature and pollutants may impose synergistic stress on soil fauna, necessitating detailed investigation. Here, we exposed Collembola (Folsomia candida) to imidacloprid (a neonicotinoid pesticide) in combination with a range of constant temperatures in a full-factorial experimental design to assess the integrated impacts on survival, growth, and bioaccumulation. The results revealed that high temperatures and imidacloprid synergistically inhibited the survival of F. candida. Under 6.4 mg/kg imidacloprid exposure, survival rates decreased by 41.38 % at 30.2 degrees C and 68.75 % at 30.5 degrees C, compared to the same temperature treatments without imidacloprid exposure. Bayesian model analysis confirmed a significant synergistic interaction between imidacloprid and temperature on survival. Interestingly, at elevated temperatures, the internal concentration of imidacloprid in F. candida significantly decreased, while the soil concentration of the insecticide remained stable. This suggests that the observed synergistic effect is not due to increased pollutant accumulation within F. candida at higher temperatures, but rather the exhaustion of energy resources needed for detoxification and thermal stress management. This dualstressor-induced energy competition underpins the synergistic interactions observed. Our findings highlight the significant synergistic effects of high temperatures and imidacloprid on Collembola, underscoring an increased ecological risk under such conditions.

The study examines the toxicity of cadmium (Cd), microplastics (MPs) and their combined pollution on wheat plants, focusing on Cd accumulation and alterations to soil physical and chemical properties. To provide guidance for understanding the physiological and ecological responses of wheat to Cd and MPs contamination. Using a soil pot experiment, the individual and combined impacts of Cd (0 mg kg(-)(1) and 5 mg kg(-)(1)) and polyvinyl chloride microplastics (PVC-MPs) (0%, 0.5%, 1.0%, and 5.0%) on various aspects of wheat growth were assessed. Partial least square (PLS) model was employed to analyze the quantitative relationship between wheat growth indicators and various physicochemical parameters. Results revealed that the PVC-MPs significantly suppressed wheat growth parameters, photosynthetic efficiency, and chlorophyll content. As the level of contamination increased, the damage to wheat chloroplasts became more severe, leaf thickness reduced, and canopy temperatures rose. Conversely, root morphology parameters and Cd accumulation in wheat plants exhibited a declining trend. Moreover, soil fertility indicators and the activities of soil urease, acid phosphatase and dehydrogenase increased in correlation with higher concentrations of PVC-MPs. The PLS model identified stomatal conductance as the critical controlling factor influencing wheat growth under the combined stress of PVC-MPs and Cd. Overall, co-occurring Cd and PVC-MPs can change wheat plant performance and soil traits. These findings provide crucial insights into the physiological and ecological impacts of Cd and microplastic co-pollution in wheat-soil systems.

It is known from the literature that the rheological behavior of soils is largely dependent on the water content in pastes and soil organic matter forming the basis of organomineral soil gels. With an increase in soil moisture, gels can swell. As a result, the viscosity of the soil paste should change. The objective of this study was to assess the effect of soil moisture on the viscosity of soil paste. Arable soil horizons were used in this work: sod-podzolic, gray forest, leached chernozem, and chestnut. During the experiments, the soil moisture was changed, whereas the water content in the pastes in each soil type remained unchanged. The viscosity of the soil paste was determined by vibration viscometry, and the size of organomineral particles in pastes was determined by laser diffractometry. Two paste viscosity peaks depending on the soil moisture were obtained for all samples studied. The paste viscosity peaks were explained from the perspective of changes in the structure of humic substances in organomineral gels upon reaching critical concentrations: micelles-supramolecular formations-fractal clusters. Apparently, the transition between structural forms of humic substances under mechanical action on pastes is accompanied by the disintegration of large gel particles and the formation of a more balanced form of humic substances at a given water content.

This study comprehensively assessed the physiological adaptations of Cymbopogon nardus (citronella) exposed to varying concentrations (25-100 mg.kg(-1)) of cadmium (Cd) and chromium (Cr). The phytoremediation potential was also evaluated over a 60d greenhouse experiment with triplicate replication, where Cd and Cr were introduced as cadmium chloride (CdCl2) and potassium dichromate (K2Cr2O7), respectively. While elevated metal concentrations adversely affected plant growth and chlorophyll content, C. nardus exhibited remarkable tolerance. This was evidenced by the upregulation of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidise (APX), alongside increases in reduced glutathione (GSH) and proline, effectively mitigating oxidative stress. However, high-intensity metal exposure eventually overwhelmed these systems, leading to reactive oxygen species (ROS) accumulation and oxidative damage. Notably, Western blot analysis revealed that Cr distinctly induced a greater reduction in ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity compared to Cd, highlighting nuanced physiological responses to different metals. The plant demonstrated substantial phytoremediation capacity, achieving bio-concentration factors (BCF) of 0.25 for Cd and 0.28 for Cr at 100 mg.kg(-1), and effectively removing 75.1% of Cd and 72.1% of Cr from contaminated soil. The novelty of this study lies in its comprehensive analysis of physiological adaptations and phytoremediation capabilities of C. nardus under both Cd and Cr stress, revealing its potential as a robust phytoremediator. The observed differential impact on Rubisco activity and efficient metal removal capacity underscore the plant's suitability for remediating soils contaminated with these prevalent heavy metals.

Context or problem: Available phosphorus (P) management is a continuous task in wheat-based systems of the UK, primarily to balance applying enough P to support high yields while avoiding unnecessary costs and damaging losses to the environment by applying too much. Objective or research question: Grain P concentration with a corresponding threshold value of 0.32 % has been proposed as a new method for P management, supporting or replacing soil test-based evaluations. The objective of this study was to investigate if this approach was a reliable option. Methods: We used data from the long-term Exhaustion Land experiment on the Rothamsted Farm in southeast England, to investigate the relations between winter wheat grain yield, grain P concentration, and Olsen P values in winter wheat over the last 32 years. Results: Our results show that maximum grain P concentrations in high yielding years are much lower than in low yielding years, indicating a dilution effect through high assimilate transfer to grains. We could not confirm a lower threshold of 0.32 % grain P as an indicator of crop P deficiency at high yields, in our trial the value was closer to 0.24 % grain P. The Olsen P test at our site was a good indicator of P response, and the Olsen P threshold value of 20 mg P kg-1 was sufficient to support the highest yields of winter wheat. Implications or significance: We conclude that P recommendations for cereals should continue to be based on soil Olsen P values, possibly supported by better estimations of P exports using grain analysis. Evaluation of the suitability of grain P concentration as a tool for P fertilizer management in cereal based systems would require more research. In the future, the existing Olsen P Index classes in the current UK Nutrient Management Guide ('RB209') should be reviewed to possibly increase P fertilizer use efficiency and reduce P losses to the environment whilst maintaining current production levels.

Differences in the fabric of reconstituted triaxial samples may increase the difficulty of achieving a unique critical state for some soils. Moreover, changes in the salt concentration of bauxite residue can result in non-unique critical state lines (CSLs). To evaluate the effects of fabric and pore-water chemistry on the critical state of bauxite residue, this paper compares the triaxial compression behavior of intact, slurry consolidated, and various forms of moist tamped samples, at a range of salt concentrations. The variations in fabric were also investigated using scanning electron microscopy and nuclear magnetic resonance (NMR) tests. The changes in pore-water chemistry were analyzed using X-ray methods and changes in salt concentration. The results showed that the particle agglomeration induced during reconstitution resulted in a more significant shift of the CSL than the decrease in salt concentration. Microimaging and shear behavior of samples showed that the slurry consolidation method may be the most suitable method for representing in situ behavior of clayey bauxite residue. NMR findings suggest that variations in water retained in the micropores of reconstituted samples stem from differences in microstructure. The implications of changes in salt concentration and sample microstructure on the design of clayey bauxite tailings storage facilities are discussed.