Nitrite contamination in environments, largely driven by human activity, can disrupt multiple physiological functions in fish. In freshwater species, nitrite is readily absorbed across the gills, accumulating internally and interfering with the oxygen-carrying capacity of blood. Here we evaluated the effects of 72-hour exposure to a moderate environmental nitrite concentration (10 μM) on zebrafish (Danio rerio), a well-established model to study the physiology of freshwater fish. Specifically, the study examined changes in routine metabolism (rMO₂), the oxygen consumption of fish at rest and in a fasted state but with spontaneous basal activity, spontaneous activity, and in the percentages of blood oxyhemoglobin (HbO₂), metHb, and nitrosyl hemoglobin (HbNO, an index of NO level in the blood), as well as the effects on mitochondrial respiratory chain activity (ETC), oxidative metabolism, ROS content, lipid peroxidation levels and antioxidant defense responses of the muscle tissue. The amount of nitrite accumulated within the muscle was also measured.

The moderate, environmentally relevant concentration of nitrite reduced rMO₂ and spontaneous activity, while increasing HbNO, indicating enhanced NO formation. Nitrite also accumulated in muscle, where it promoted oxidative stress and altered aerobic metabolism, including an increase in mitochondrial efficiency, antioxidant capacity. These changes reflected coordinated metabolic adjustments.

In conclusion, acute exposure to a moderate environmental concentration of nitrite induces nitrite accumulation in skeletal muscle and alters muscular metabolism and the redox state of adult zebrafish. The results underscore the sensitivity of fish to nitrite levels commonly encountered in impacted freshwater habitats.

Emerging contaminants such as platinum group elements (Pt, Pd, Rh), silver (Ag), antimony (Sb), and cobalt (Co) are increasingly reported in urban soils, yet their spatial distribution and environmental behaviour remain insufficiently characterised. We applied a geographic information system (GIS)-based approach to evaluate the spatial variability of Ag, Co, Pt, Rh, Sb, and Pd (inferred, not directly measured) in 137 surface soil samples (0–3 cm) collected across urban, industrial, and garden areas of Alcalá de Henares, Spain. Spatial interpolation using inverse distance weighting (IDW; power = 2, 12 neighbours), based on commonly applied parameters in urban soil mapping, revealed distinct patterns for each element. Ag and Co showed heterogeneous distributions, with higher concentrations in garden and industrial soils (Ag: up to approx. 0.9 mg/kg; Co: up to approx. 19 mg/kg), likely influenced by biosolids application and historical industrial activity. Pt and Rh were elevated near major traffic routes, consistent with vehicular emissions as dominant sources. Sb exhibited marked urban hotspots associated with brake wear and industrial legacy inputs. Although Pd was not analysed, its likely co-occurrence was inferred from the spatial congruence of Pt–Rh and shared emission sources. Correlation analysis supported the spatial findings, highlighting an anthropogenic Rh–Sb–Mo cluster (Mo included as part of the correlation dataset) and a mixed geogenic–anthropogenic profile for Co. Overall, the integration of spatial mapping and multivariate statistics demonstrates the utility of GIS for identifying contamination hotspots, supporting source apportionment and informing soil surveillance and biomonitoring strategies. Our results emphasise the need to consider less-monitored elements in regulatory frameworks to better protect vulnerable populations in complex urban environments.

_{Introduction: The already increased greenhouse gas emissions are growing, beyond the factors of climate change and military operations, leading to harmful environmental implications, before, during, and after armed conflicts, that both need detailed assessment.}

_{Methods: Defining the context of «carbon footprint», «greenhouse gas emissions», and «methane emissions», the popular 5.5% footprint of the largest carbon polluter, the military, emerges. Based on analytical tables with emissions sources and their CO2e/Mt percentage, the four categories of pollutant emissions (scopes 1, 2, 3, and 3 plus) are also identified.}

_{Simultaneously, the regulatory framework regarding environmental protection against military emissions is investigated holistically, at international (humanitarian, environmental, and criminal), European, and jurisprudencial levels.}

_{Despite the increased amount of emissions, which is growing, «additional» emissions (front line) and massive military expenses are exacerbating this amount. However, states' non-accountability or double reporting, given contemporary examples of warring countries (Russia, Ukraine, Georgia), causes data gaps and uncertain evaluations of emissions' accounting, for which three key calculation methods are used.}

_{Observing the devastating repercussions of armed conflicts on the quality of air, soil and water, and the aquifer horizon, with climate change on top, three possible climate scenarios arise and viable solutions have to be sought to align with essential guidelines (e.g., 1.5 oC goal—Paris Agreement).}

_{Results: Identifying the deep sources—causes of the issue—through terms analysis and emissions accounting; assessing the quantity of military pollutant emissions based on poor data to observe, perceive, and combat the caused environmental side-effects.}

_{Conclusions: In a nutshell, the military contributes noticeably to the global increase in GHG emissions. Despite the obstacle of the voluntary nature of states' emissions reporting, data collection is truly substantial in accurately assessing the environmental effects of armed conflicts and in urgently managing them, adapting with global climate commitments.}

The Po River Delta, situated in the Northwestern Adriatic Sea, is the largest river delta in Italy. It covers an area of 685 km² and includes seven coastal lagoons. Since spring 2023, the presence of the alien invasive species Callinectes sapidus has increased rapidly in the area, causing damage, especially to the shellfish sector.

The blue crab is an opportunistic predator known to feed on macrozoobenthic organisms. Since macrozoobenthos is one of the biological quality elements used in the ecological classification of transitional waters under the Water Framework Directive (2000/60/EC), its monitoring is essential to assess potential impacts of the blue crab invasion, mostly through analysis of changes in benthic community composition and abundance. To this aim, two sampling campaigns were carried out in 2024 and 2025 at 11 stations across five lagoons of the Po River Delta.

The results were compared with data from previous years (2021-2023), collected within the WFD network.

The analysis of diversity and ecological indices showed variable trends over the years, with differences only identified for density, with lower values in 2024 and 2025 compared to the previous years.

Multivariate analyses also confirmed differences between 2024-2025 and 2021-2023 (ANOSIM for Factor “Year” Global R: 0.429; p=0.1%).

SIMPER analysis showed a different distribution of common species over the years, including Heteromastus filiformis, and species of the genus Streblospio, Gammarus insensibilis and Nephtys hombergii.

Also, the M-AMBI index confirmed a deterioration in ecological quality status over the last two years.

Even though the environmental status of the Po River Delta lagoons is influenced by multiple anthropogenic pressures and shows interannual variability, the results suggest that, considering market data showing a sharp increase in blue crab catches since July 2023, the blue crab may have affected the biodiversity of the macrozoobenthic community during the past two years.

Mercury (Hg) is a global contaminant of significant concern, especially due to its transformation into methylmercury (MeHg), a potent neurotoxin. River biofilms, such as those found in the Tapajós River, are recognized as crucial hotspots for microbial methylation of Hg. This study investigated the interaction between Hg and selenium (Se), an element known to mitigate Hg toxicity, in freshwater biofilms. The objective was to evaluate Hg speciation and correlate it with the detection of key genes involved in Hg methylation and resistance (hgcA, merA, gcs, dsrA) under different exposure conditions to IHg and SeO₃^2-. The results demonstrated that biofilms act as efficient sinks for Hg, with high bioaccumulation of the metal. Speciation analysis revealed that Hg remained predominantly in the inorganic form (IHg) in the dissolved phase, with MeHg was below the detection limits, suggesting a low methylation rate under experimental conditions. PCR analysis revealed a detection pattern suggesting strong selectivity and toxicity of IHg. The resistance gene merA was not detected in treatments with IHg alone and IHg+ SeO₃², suggesting the elimination of the subpopulation carrying this gene due to toxicity. Crucially, the methylation gene hgcA, which was detected in single treatments with IHg, was not detected under the co-exposure to IHg + SeO₃^2-, suggesting that SeO₃^2- mitigated the methylation. From an environmental perspective, our results suggest that naturally occurring Se may play a protective role in Amazonian ecosystems impacted by Hg, reducing the bioavailable fraction of this potent neurotoxin and, consequently, eliminating susceptible microbial populations. This has important implications for risk assessment and potential bioremediation strategies in regions affected by artisanal gold mining and other sources of Hg contamination.

The Sono-Galvano-Fenton is a hybrid advanced oxidation process designed to harness the advantages of each process, namely the in-situ production of the Fe²⁺ catalyst (through the Galvano-Fenton process) and hydrogen peroxide (H2O2; through sonochemistry), as well as the plausible synergetic production of the hydroxyl radical (HO^●). In the present study, the hybrid technique is applied to the degradation of Malachite Green using different coupling strategies, at an acoustic frequency of 600 kHz and an acoustic power of 120 W, with a pre-optimized electrochemical configuration of 1 anode to 6 cathodes. A numerical model is also applied to assess the role of sonication at both microscopic and macroscopic scales. The experimental results revealed an extended residence time of the emerging pollutant within the 300 mL reactor in batch mode when both techniques are coupled in series, offering an advanced purely sonochemical degradation of the extent of Fenton reagent H₂O_{2 production}. The process is then engineered in continuous mode with recirculation of the treated solution to overcome this limit. The numerical model of sonolysis in an air atmosphere at the reactor scale demonstrated apicomolar production of hydrogen peroxide and hydroxyl radicals at 200 kHz, suggesting a frequency shift toward this value to enhance both processes ' coupling.

The degradation of tetracycline, a persistent antibiotic pollutant, was systematically investigated using Mg-doped nickel aluminate(90.19%), Co-doped nickel aluminate (74.35%), Cu-doped nickel aluminate (81.63%), Fe-doped nickel aluminate (64.28%), and undoped nickel aluminate (62.68%) photocatalysts. In each experiment, 12.5 mg of tetracycline and 25 mg of the corresponding catalyst were added to 100 mL of distilled water, and the reaction was monitored for 120 minutes under visible light. SEM analysis revealed distinct dopant-dependent morphologies, ranging from agglomerated particles to well-defined layered structures, which influence surface adsorption and catalytic activity. The particle size of all nickel aluminate catalysts was found to range from 50 to 180nm. Photoluminescence (PL) spectra showed that Mg-doped nickel aluminate exhibited lower PL intensity than Cu- and Co-doped samples, indicating more efficient suppression of electron-hole recombination. The structural and optical characteristics of the corresponding nickel aluminates were directly correlated with the observed enhanced tetracycline removal rates, particularly for the doped catalysts. Kinetic studies confirmed pseudo-first-order behavior, and the degradation efficiency and the resulting mechanistic pathway were comprehensively evaluated for Tetracycline degradation. Overall, the combined evidence demonstrates that metal doping substantially improves the photocatalytic performance of nickel aluminate, primarily through optimized surface morphology and more efficient charge-carrier dynamics, offering a promising approach for tetracycline remediation in contaminated water systems.

Mechanical processing of titanium dioxide-containing coatings and composites generates airborne particulate emissions that contribute to occupational and near-field environmental exposure. Titanium dioxide nanoparticles (TiO₂-NPs) are widely used in industry, and their potential to cause adverse effects in the respiratory system raises concerns for both environmental impact and human health risk assessment. Importantly, new approach methodologies (NAM)-relevant computational toxicogenomic models for TiO₂-NPs are derived almost exclusively from studies of “free” nanoparticles in simplified media, whereas real-world scenarios involve complex sanding-dust (SD) mixtures. We investigated whether inhalation of TiO₂-NP SD produces lung transcriptomic responses comparable to those induced by free TiO₂-NPs, and whether existing transcriptomic biomarkers can serve as mechanistic monitoring tools for SD exposure.

We analyzed in vivo lung transcriptomic data for mice exposed to free TiO₂-NPs and SD emissions across multiple doses (54–486 μg/animal), post-exposure periods (1–28 days), and particle sizes (10–38 nm), yielding 649 differentially expressed genes across 54 exposure scenarios. Unsupervised machine learning methods (principal component analysis, hierarchical clustering, correlation analysis) were applied to identify global patterns and relate SD-induced signatures to established TiO₂-NP biomarkers.

Analyses showed that SD-induced profiles clustered closely with free TiO₂-NP exposures, indicating broadly comparable transcriptomic responses. We further observed that many key biomarkers previously perturbed after free TiO₂-NP inhalation (Saa, Ccl, Cxcl, Il families relevant to acute neutrophilic inflammation and chemokine-driven response) are strongly upregulated following SD inhalation at 1 day post-exposure, indicating a pronounced acute response to sanding-generated particulate matter relative to later time points. These findings support the extension of NAM-relevant computational toxicogenomic approaches and transcriptomic biomarkers from free TiO₂-NPs to more realistic particulate emissions, thereby strengthening mechanism-based environmental impact and regulatory-relevant health risk assessment of TiO₂-containing materials.

Funded via the Polish National Science Centre in the frame of the TransNANO project (UMO-2020/37/B/ST5/01894).

Production of electric vehicles (EVs) is expected to promote sustainability by decreasing fossil fuel use in the mobility sector. However, the rapid development of a global industry chain for the production of electric engines and batteries has exacerbated the inequality of resource utilization. New environmental impacts linked to material flows associated with the industry chain (steel, lithium and other minerals) are a source of huge concern and upstream, midstream and downstream (extraction, production, trade and use) shared responsibility. This study developed a multi-layer trade network model of “steel-minerals-electric vehicles” industry chain and provided a scientific framework for resource flow and responsibility allocation based on Odum’s Emergy Accounting (EmA) approach. Results firstly show that the worldwide trade volume and the number of involved countries increased enormously from 2017 to 2021 and keep growing. Secondly, in spite of the aim of mobility decarbonization, non-renewable energies (mainly coal) are still used in upstream countries. Finally, trade patterns mostly flow from upstream to midstream steel and other minerals producing and refining countries, and then to downstream EVs' manufacturers and users, from which trade flows go back to midstreamand upstream countries. Environmental impacts can be differently allocated to these countries, among producers and users. This reflects the huge imbalance among production and use in the different stages of the worldwide “steel--minerals--electric vehicles” industry chain. By means of EmA-based indicators (Environmental Loading Ratio, Emergy Sustainability Index and other valuation indicators), we can quantify the sustainability of each stage of the industry chain, in so allocating both impacts and responsibility according to different types of production and patterns of electric vehicle use. Based on these results, our study proposes policy implications for promoting regional industrial ecological sustainability from the perspectives of industry chain, trading partners and countries.

In Mediterranean regions, reservoirs play a crucial role in securing urban water supply. Despite the large number of reservoirs in Portugal, their management still largely follows their primary designated use—public supply, irrigation, or hydropower—which limits progress towards achieving good ecological potential. This highlights the need for integrated, ecosystem-based management approaches. The Serra Serrada reservoir (41.886° N, –6.766° W), which supplies the city of Bragança (NE Portugal), exemplifies the importance of management strategies that stabilise water-level fluctuations and support good ecological potential in line with the Water Framework Directive. With a total storage capacity of 1,680,000 m³ and located within a Key Biodiversity Area, this reservoir was assessed through an environmental diagnosis conducted at five geographic levels: territory, catchment, reservoir surroundings, reservoir, and downstream territory. Field surveys, bibliographic data, and stakeholder consultations supported the assessment of pressures and the definition of mitigation measures. Proposed actions include the restoration of wetlands and riparian vegetation and the promotion of water efficiency in public buildings. Studies carried out in Bragança—covering schools, the municipal market, student residences, and the municipal swimming pool complex—report an annual water consumption of 324,239.62 m³. Estimated savings range from 12.4% to 75%, depending on building type and the efficiency measures applied. Improving water efficiency in these facilities represents a priority action, as it directly contributes to sustainable urban water use. The implementation of rainwater harvesting systems and nature-based solutions, such as green roofs, can further enhance water sustainability. Such measures in the urban water cycle can indirectly support higher and more stable water levels, improved water quality, and the overall ecological integrity of the Serra Serrada reservoir.