Search Results (206)

The aim of this study is to determine the characteristics of the chemical and mineral composition of sediment layers in a technogenic settling pond. This pond is located on urban land in Berezniki (Perm Krai, Russia), outside the territory of operating industrial facilities, and contains alkaline saline industrial wastes. The origin of this waste was related to sludge from the Solvay soda production process, which had been deposited in this pond over a long period of time. However, along with the soda waste, the pond also received wastewater from other industries. As a result, the accumulated sediment is characterized by variation in morphological properties both in depth and laterally. Five undisturbed columns were taken to study the composition of the accumulated sediment. The obtained samples were analyzed by X-ray diffraction (XRD), synchronous thermal analysis (STA), and X-ray fluorescence (XRF) analysis. The results showed that the mineral composition of bottom sediments in each layer of all studied columns is characterized by the predominance of calcite precipitated from wastewater. Along with calcite, due to the presence of magnesium and sodium in the solution, other carbonates precipitated—dolomite and soda (natron), as well as complex transitional carbonate phases (northupite and trona). Together with carbonate minerals, the chloride salts halite and sylvin, sulfate minerals gypsum and bassanite, and pyrite and nugget sulfur were established. The group of terrigenous mineral components is represented by quartz, feldspars, and aluminosilicates. The chemical composition of sediments in the upper part of the section generally corresponds to the mineral composition. In the lower sediment layers, the role of amorphous phase and non-mineral compounds increased, which was determined by the results of thermal analysis. The content of heavy metals and metalloids also increases in the middle and lower sediment layers. When categorized according to the Igeo value, an excessive degree of contamination (class 6) was observed in all investigated columns for copper content (Igeo 5.2–6.1). Chromium content corresponds to class 5 (Igeo 4.1–4.6), antimony to class 4 (Igeo 3.0–4.0), and lead, arsenic, and vanadium to classes 2 and 3 (moderately polluted and highly polluted). The data obtained on variations in the mineral and chemical composition of sediments represent the initial information for the selection of methods of accumulated waste management. Full article

Tyre wear particles (TWPs), generated from tyre-road abrasion, are a pervasive and under-regulated environmental pollutant, accounting for a significant share of global microplastic contamination. Recent estimates indicate that 1.3 million metric tons of TWPs are released annually in Europe, dispersing via atmospheric transport, stormwater runoff, and sedimentation to contaminate air, water, and soil. TWPs are composed of synthetic rubber polymers, reinforcing fillers, and chemical additives, including heavy metals such as zinc (Zn) and copper (Cu) and organic compounds like polycyclic aromatic hydrocarbons (PAHs) and N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD). These constituents confer persistence and bioaccumulative potential. While TWP toxicity in aquatic systems is well-documented, its ecological impacts on terrestrial environments, particularly in agricultural soils, remain less understood despite global soil loading rates exceeding 6.1 million metric tons annually. This review synthesizes global research on TWP sources, environmental fate, and ecotoxicological effects, with a focus on soil–plant systems. TWPs have been shown to alter key soil properties, including a 25% reduction in porosity and a 20–35% decrease in organic matter decomposition, disrupt microbial communities (with a 40–60% reduction in nitrogen-fixing bacteria), and induce phytotoxicity through both physical blockage of roots and Zn-induced oxidative stress. Human exposure occurs through inhalation (estimated at 3200 particles per day in urban areas), ingestion, and dermal contact, with epidemiological evidence linking TWPs to increased risks of respiratory, cardiovascular, and developmental disorders. Emerging remediation strategies are critically evaluated across three tiers: (1) source reduction using advanced tyre materials (up to 40% wear reduction in laboratory tests); (2) environmental interception through bioengineered filtration systems (60–80% capture efficiency in pilot trials); and (3) contaminant degradation via novel bioremediation techniques (up to 85% removal in recent studies). Key research gaps remain, including the need for long-term field studies, standardized mitigation protocols, and integrated risk assessments. This review emphasizes the importance of interdisciplinary collaboration in addressing TWP pollution and offers guidance on sustainable solutions to protect ecosystems and public health through science-driven policy recommendations. Full article

Water scarcity is a global crisis and of particular concern in arid regions like Morocco. One creative solution is mining unusual water sources, such as landfill leachate. The presence of nitrogen in the sediment was studied as part of the use of sugar lime sludge in treating landfill leachate for irrigation purposes. A volume of 40 L of landfill leachate was treated with three different concentrations of sugar lime sludge (25%, 35%, and 50%). After homogenization and agitation of the mixture for 24 to 36 h, it was permitted to settle through the concrete decantate and supernatant. Nitrogen was efficiently decanted into the sediment during the composting process with green waste, enhancing the quality of the finished compost. The supernatants underwent physicochemical and microbiological analyses to ascertain their suitability for irrigation. The findings showed that the number of fecal streptococci was decreased by 99.13% at a 25% concentration of sugar lime sludge. The percentage of organic matter in the sediment rose from 10% to 40%, suggesting that the leachate had partially depolluted. The pH and electrical conductivity of the supernatants were within irrigation guidelines. The safety of diluted supernatants for plant germination was verified by phytotoxicity experiments conducted on maize seeds. The compost made from the decantate and green waste showed acceptable physical and chemical properties. Statistical analysis was conducted using JAMOVI software version 2.6.26. One-way ANOVA was used to assess the significance of treatment effects on microbiological and physicochemical parameters. The results confirmed statistically significant differences (p < 0.05) between the sludge concentrations, supporting the effectiveness of the treatment process. This study demonstrates how sugar lime sludge can be used to turn landfill leachate into a sustainable and safe irrigation water source, resolving environmental issues and promoting creative water management techniques. Full article

Experiences in the production, transportation and preparation of crude oil for transportation have shown that specific problems arise related to their mixing, including water contamination. In recent years, interest in studying these problems has significantly increased, mainly due to the development of extraction technologies for heavy oil samples and bitumen. Along with various difficulties encountered during the pipeline transportation of complex rheological crude oil blended with each other and with light oil, including condensate (such as sedimentation, etc.), imbalances are also observed during storage, as well as in the processes of delivery and reception. During the dehydration of oil mixtures, a synergistic effect is observed in the consumption of demulsifier. The article investigates, in accordance with international standards and based on laboratory tests, how the physico-chemical properties (density, viscosity, freezing point, saturated vapor pressure, chemical composition) of mixtures formed by blending various grades and compositions of Azerbaijani oil examples with each other and with condensate change and how the efficiency of dehydration of oil mixtures is affected by the mixing ratio of the oil involved. It was found that the quality indicators (physico-chemical parameters) of oil mixtures differ non-additively from the initial parameters of the blended products and in some cases, this difference is even observed with anomalies. Moreover, depending on the mixing ratio of the oil, variations in the consumption of demulsifier were also identified. Full article

Environmental variability modifies forest structure through interactions among soil properties, topography, and climate. These factors influence the occurrence of contrasting forest types in northern Amazonia (Brazil), such as forests in highlands (Terra Firme) and forests under regular flooding (Várzea). Flooding regimes influence soil formation and modify soil geochemistry, nutrient distribution, and organic matter accumulation, shaping forest structure and composition. The objective was to determine the relationships between structure and soil characteristics in non-flooded and flooded tropical forests. We compared forest structure and soil characteristics at both conditions (n = 2 treatments × 20 replicas = 40 plots) using univariate and multivariate analyses. We found significant differences in most of the studied variables between forest types, both chemical and physical properties. Our results showed that flooding defines forest structure and composition (e.g., tree density, height, and volume) and influences soil nutrient characteristics. Floodplain forests exhibited higher soil nutrient concentration and organic carbon content, likely due to periodic litter accumulation, sediments, and reduced decomposition rates. In contrast, non-flooded forests were characterized by lower nutrient levels, higher sand content, and greater forest structure values (e.g., height, basal area, and volume). These insights contribute to understanding the functioning of both forest ecosystems. Full article

The internal nutrient load of natural and artificial lakes is a worldwide problem. To minimize its potential risks, the dredging of the highly eutrophic shallow first reservoir of Kis-Balaton (Lake Hídvégi) is planned in the near future. Our study aimed to evaluate the potential effects of dredging and desiccation on water and sediment quality. Experimental dredging was carried out in the northernmost part of Lake Hídvégi (2023). The physical and chemical characteristics of the sediment and nutrient loss during desiccation were examined in a column experiment. The relationships between the properties of leachate and sediment were identified using principal component analysis (SPSS). Spatial variations in sediment particle size distribution, nutrient content, and other chemical parameters (e.g., organic matter) suggest that deeper core sampling than the depth of preliminary dredging is necessary for a more comprehensive assessment of potential impacts. We found that spatiotemporally varying the dominance of chemical and biological processes affects the amount of and changes in phosphorus fractions under lake-/sediment-specific conditions. The readily available calcium- and iron-bound phosphorus, texture, and organic matter content of the sediment play an important role in phosphorus fixation/release. Based on our results, dredging and desiccation are feasible within the intended operating parameters. The sediment’s composition does not preclude potential agricultural disposal. Full article

Sediment is a core part of lake ecosystems, and its organic matter (OM) content is a key indicator of lake ecological health and regional carbon cycling. OM provides nutrients for phytoplankton and algae in water, thereby influencing the degree of lake eutrophication. However, excessively high OM content may trigger water eutrophication, alter sediment’s physical and chemical properties, and ultimately threaten the stability and health of ecosystems. This study innovatively selected Poyang Lake, Taihu Lake, Qinghai Lake, and Hulun Lake from China’s four major geographical regions to systematically investigate sediments’ OM content, sources, and distribution characteristics at different times. The results showed that the organic matter content of sediments in lakes from different regions varied significantly and was influenced by multiple factors, such as watershed characteristics, eutrophication levels, human activities, and climate change. Poyang Lake and Taihu Lake, characterized by high levels of agricultural activities and urbanization within their basins, exhibit significant fluctuations in organic matter content, with total organic carbon (TOC) levels ranging from 0.35% to 2.9% and 0.7% to 2.4%, respectively. In contrast, Qinghai Lake and Hulun Lake, influenced by natural conditions and ecological policies, show relatively stable TOC levels, ranging from 1.3% to 2.75% and 1.25% to 3.58%, respectively. By analyzing sediments’ OM content and combining methods such as organic carbon, nitrogen isotopes, and organic C/N ratios, it is possible to effectively assess the ecological health of lakes, provide critical data support for pollution control, and play a significant role in carbon cycle management. Full article

The classification of shale is commonly based on lithofacies structure, mineral content, organic carbon content, physical and chemical parameters, and element contents. A geochemical classification method based on the compositional data of shale is proposed which divides shale, sedimentary rocks, sediments, and soils into six types, named siliceous, felsic, silicate, calcsilicate, dolomitic, and calcareous components, and numbered from type 1 to type 6, respectively. Sedimentary rocks in China, including mudstone (shale), sandstone, carbonate rocks, and siliceous rocks, are selected to test the method, and the results show that the method can accurately classify not only shale but also other sedimentary rocks. Shale samples from a drill well in southern Sichuan area are classified based on the proposed method as an illustration in a line graph. Furthermore, the stream sediments and soils from geochemical survey projects in the southern Sichuan area are also classified based on their compositional data. Based on the classification results, a geochemical map is drawn and compared with the strata lithology. These results indicate that the new classification method is suitable for shale, sedimentary rocks, sediments, and soils, and illustrates clear geochemical properties based on their classified types. Full article

The introduction of a new insulating oil or, for instance, a new type of insulation or sealing into a transformer necessitates tests for material compatibility. Compatibility tests of liquids with the structural internal materials of transformers are conducted to prevent undesired interactions between insulating fluids and the formation of products that could lead to the generation of undesirable ions, sediments, or chemical compounds that result in a reduction in the dielectric property performance of the fluid. This includes chemical reactions (hydrolysis, hydrogenation, oxidation, formation of sulfates or sulfides, etc.) and degradation, the formation of conductive suspensions, the generation of undesirable condensation, and alterations in other fluid properties, such as interfacial tension between oil and water, viscosity, flashpoint, etc. Changes must also not occur in the strength and hardness of gasket material, which could result in undesirable fluid leakage. This paper describes the novel methodology and results of several proposed tests, including the impact on oil viscosity, material hardness, FT-IR analysis of oils, partial discharges in different oils, dielectric properties, and more, conducted during compatibility and aging tests at 120 °C and 140 °C performed on materials used in particular distribution transformers being prepared for natural ester use. The results show notable differences in the behavior of insulating fluids and aged submerged materials. While mineral oils exhibit lower dissipation factors compared to natural esters, the latter demonstrate slower and less severe hardening effects on gaskets during high-temperature aging (e.g., Shore 35.25 in mineral oil vs. 21–22.5 in natural esters). The tensile strength of the tested cable ties decreased significantly (from 260 to approx. 60 N) in mineral oil but increased in natural ester (320 N/120 °C exposition). This study also highlights a novel insight into partial discharge mechanisms, where differences in viscosity, conductivity phenomena, and dielectric constants result in presented differences in inception voltages and prebreakdown activity. Full article

This study focused on the aquatic insect orders that serve as biological indicators. Ephemeroptera, Plecoptera, Trichoptera, Coleoptera, and Odonata were studied with their relationships to physical, chemical, hydrological and morphological variables in 14 streams on three Croatian mountains: Papuk, Medvednica and Psunj. From 675 samples collected in three dominant sediment microhabitats (e.g., macrolithal and mesolithal) in each stream, we identified 130 macroinvertebrate taxa. The most abundant group was Ephemeroptera (36 taxa). Aquatic insect assemblages between Papuk and Psunj showed higher similarity due to the geographical proximity of these two mountains, which is expressed as spatial connectivity. In spring, greater variability and diversity of investigated aquatic insects were observed due to the phenology of studied insects. The combination of environmental and morphological properties (e.g., oxygen concentration and substrate type) had the most significant influence on shaping the assemblage of aquatic insects of Psunj, while morphological properties were the most important in shaping aquatic insect assemblages on Papuk (e.g., streambed width) and Medvednica (e.g., elevation). Baetis sp. was the dominant taxon in summer, Protonemura montana in spring, and Leuctra sp. in autumn. Seasonal shifts in environmental conditions lead to functionally unique communities that utilize the pool of available seasonal resources. The dominance of feeding groups varied by season, with scrapers and collector–gatherers being most prevalent in summer, while shredders were dominant in spring. The results on the relationships between environmental characteristics and species richness, functional structure, and distribution of aquatic insects in mountain streams provide important clues for future research and conservation strategies in these vulnerable ecosystems. Full article

Diterpenoids from marine-derived organisms represent a prolific source of secondary metabolites, characterized by their exceptionally promising chemical structures and pronounced pharmacological properties. In recent years, marine diterpenoids have garnered considerable attention and are regarded as a prominent area of scientific research. As a vital class of metabolites, diterpenoids show diverse biological activities, encompassing antibacterial, antifungal, antiviral, anti-inflammatory, inhibitory, and cytotoxic activities, among others. With the rapid advancement of equipment and identified technology, there has been a tremendous surge in the discovery rate of novel diterpenoid skeletons and bioactivities derived from marine fungi over the past decade. The present review compiles the reported diterpenoids from marine fungal sources mainly generated from January 2000 to December 2024. In this paper, 515 diterpenoids from marine organisms are summarized. Among them, a total of 281 structures from various fungal species are included, comprising 55 from sediment, 39 from marine animals (predominantly invertebrates, including 17 from coral and 22 from sponges), and 53 from marine plants (including 34 from algae and 19 from mangrove). Diverse biological activities are exhibited in 244 compounds, and among these, 112 compounds showed great anti-tumor activity (45.90%) and 110 metabolites showed remarkable cytotoxicity (45.08%). Furthermore, these compounds displayed a range of diverse bioactivities, including potent anti-oxidant activity (2.87%), promising anti-inflammatory activity (1.64%), great anti-bacterial activity (1.64%), notable anti-thrombotic activity (1.23%), etc. Moreover, the diterpenoids’ structural characterization and biological activities are additionally elaborated upon. The present critical summary provides a comprehensive overview of the reported knowledge regarding diterpenoids derived from marine fungi, invertebrates, and aquatic plants. The systematic review presented herein offers medical researchers an extensive range of promising lead compounds for the development of marine drugs, thereby furnishing novel and valuable pharmaceutical agents. Full article

The aim of this study was to investigate how biomass production and element distribution (nutrients and heavy metals) among plant organs (roots, stems, and leaves) were influenced by substrate physical and chemical properties, using acidophilic plants of Vaccinium corymbosum cultivars Bluecrop and Duke. A greenhouse pot experiment was conducted with highbush blueberry plants grown in an uncontaminated acidic peat-based control substrate (TS0) and two alkaline substrates enriched with remediated sediment (TS50 and TS100), characterized by high pH, Ca, and heavy metal concentrations. Both plant cultivars that were cultivated in sediment–based substrates exhibited a substantial reduction in plant growth, biomass production, and leaf chlorophyll levels. Limited translocation of microelements from belowground organs to leaves was observed across all plant samples. Cu, Fe, and Pb were predominantly accumulated in the roots of plants grown in TS-based substrates, with both cultivars acting as excluders for these metals by restricting their transport from roots to shoots. Mn and Zn were primarily retained in the stems and roots of highbush blueberry plants, with lower leaf accumulation. Notably, only Mn exhibited high translocation and bioaccumulation factor values (on average, 3.43 and 6.68, respectively), highlighting the species’ strong capacity for Mn accumulation. Specifically, control plants showed significantly higher Mn concentrations than those grown in TS-enriched substrates, likely due to the acidic conditions that enhance the bioavailability of this metal and the low Ca concentration in TS0, which is known to disrupt Mn accumulation in shoots. However, this accumulation did not reach toxic levels for the plants and did not negatively impact the physiological processes of control plants, which remained particularly efficient in the Duke cv, known for its Mn resistance. This study highlights the ability of highbush blueberry plants to selectively accumulate heavy metals when grown in polluted substrates under suitable conditions, making them a valuable model for understanding metal accumulation mechanisms in the Ericaceae family. Full article

Two sets of sediment samples were collected from the Sarigiol basin, Greece, aiming to evaluate the environmental consequences of the industrial activity in the area by assessing their magnetic properties with the magnetic susceptibility method. Chemical composition and morphological characteristics of magnetic particles were defined by EDX analysis and scanning electron microscopy, respectively. Based on the results, most of the study area shows positive values of the difference between X_LF values of the samples, indicating the influence of fly ash dispersion from Agios Dimitrios and Kardia power plants and the conveyor belt, down to a depth of 50 cm. Negative values in the NE, W and S parts of the study area are attributed to ophiolite complexes. Anthropogenic and lithogenic magnetic particles were identified at a 50 cm depth, in the form of spheres and octahedrons, respectively. Fe is the dominant element while Al, Si, Mg and Ca were found in minor amounts. Cr increases with depth, pointing mainly to a lithogenic source, while Ti decreases, suggesting a relationship with the dispersed fly ash particles. Mn and Zn were found in limited magnetic spheres. These findings highlight the need for effective environmental management strategies and are valuable keys for soil pollution control. Full article

This study investigates the sustainable use of seabed dredged sediments and water treatment sludges as construction materials using combined dewatering and cement stabilization techniques. Dredged sediments and water treatment sludges, typically considered waste, were evaluated for their suitability in construction through a series of dewatering and stabilization processes. Dewatering significantly reduced the initial moisture content, while cement stabilization improved the mechanical properties, including strength and stiffness. The unconfined compressive strength (UCS), shear modulus, and microstructural changes were evaluated using various analytical techniques, including unconfined compression testing, free–free resonance testing, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The results show a direct correlation between reduced w/c ratios and increased UCS, confirming the potential of treated sludge as a subbase layer for roads and landfill liners. A chemical analysis revealed the formation of calcium silicate hydrate (CSH) and ettringite, which are critical for strength enhancement. This approach not only mitigates the environmental issues associated with sludge disposal but also supports sustainable construction practices by reusing waste materials. This study concludes that cement-stabilized dredged sediments and water treatment sludges provide an environmentally friendly and effective alternative for use in civil engineering projects. Full article

Wildfires pose a significant threat to the entire ecosystem. The impacts of these wildfires can potentially disrupt biodiversity and ecological stability on a large scale. Wildfires may alter the physical and chemical properties of burned soil, such as particle size, loss of organic matter and infiltration capacity. These alterations can lead to increased vulnerability to geohazards such as landslides, mudflows and debris flows, where soil erosion and sediment transport play a crucial role. The present study investigates the impact of wildfire on soil erosion by conducting a series of laboratory experiments. The soil samples were burned using two different methods: using firewood for different burning durations and using a muffle furnace at an accurately controlled temperature within 400 °C∼1000 °C. The burned soils were subsequently subjected to surface erosion by utilizing the constant head method to create a steady water flow to induce the erosion. In addition, empirically based theoretical models are explored to further assess the experimental results. The experimental results reveal a loss of organic matter in the burned soils that ranged from approximately 2% to 10% as the burning temperature rose from 400 °C to 1000 °C. The pattern of the grain size distribution shifted to a finer texture in the burned soil. There was also a considerable increase in soil erosion in burned soils, especially at a higher burn severity, where the erosion rate increased by more than five times. The empirical predictions are overall consistent with the experimental results and offer reasonable calibration of relevant soil erosion parameters. These findings demonstrate the importance of post-fire erosion in understanding and mitigating the long-term effects of wildfires on geo-environmental systems. Full article