Search Results (218)

Brake dust (BD) generated by vehicle braking systems, including those of cars and trains, contains various Potentially Toxic Elements (PTEs) that may pose risks to human health and the environment, particularly in soils where it accumulates. This study aims to evaluate differences in the chemical composition of BD emitted by road and railway transport, to analyze its deposition mechanisms in soil, and to estimate the associated carcinogenic (CR) and non-carcinogenic (HQ) risks from ingestion and dermal exposure. Two sites were selected: one adjacent to a busy roadway and the other near a railway line. At both locations, soil-sampling transects were established perpendicular to the emission sources at distances of 3, 6, 15, 25, and 45 m. Elemental concentration analyses were integrated with magnetic measurements, which are selective for magnetic iron oxide particles. The results confirm elevated concentrations of several metals at both sites. Both elemental and magnetic data reveal a clear deposition gradient, with the highest accumulation within 15 m of the source, followed by a gradual stabilization up to 45 m. However, the railway site exhibited significantly higher concentrations than the road site, highlighting the relevance of non-exhaust emissions (NEEs) from railway traffic, which remain poorly investigated. While HQ was non-significant, CR associated with Pb-, Ni-, and As-rich BD exceeded acceptable threshold values, particularly for ingestion exposure at the railway site. These results highlight the significance of NEEs from rail traffic in terms of soil contamination and risk assessment. Full article

Zinc (Zn) in excess is very toxic for plants and can limit agriculture. Carbon-based engineered nanomaterials with high electron mobility and electron-accepting capability may be essential for mitigating heavy metal stress. In the present study, the protective role of some fullerene C₆₀ derivatives (fullerenol [C₆₀(OH)_22–24] and the arginine C₆₀ [C₆₀(C₆H₁₃N₄O₂)₈H₈]) were tested for the first time against Zn toxicity in Cucumis sativus L. (cucumber). Plants were grown hydroponically at three concentrations of fullerenes (0, 2, and 10 mg L⁻¹) without or with 40 µM Zn for 17 days. Plant growth, leaf chlorosis, and nutritional imbalances in combination with a metabolomics approach were analyzed. The Zn-treated plants show chlorotic leaves, the retarded growth of shoots (−20%), and roots (−49%) and nutrient imbalance. Addition of fullerene C₆₀ derivatives suppressed loss in the dry biomass of leaves (15%) and roots (40%; fullerenol only) induced by high Zn. However, they did not alter leaf chlorophyll, shoot dry biomass, and elemental composition, including leaf Zn. Moreover, the Zn of xylem sup from roots remained unchanged by fullerenes. In an adsorption experiment, the amounts of Zn adsorbed by tested C₆₀ were below the detection limits. The addition of C₆₀ derivatives slightly changed the metabolite profiling in stressed plants. Nevertheless, in fullerene-treated plants, the abundance of some Zn-responsible metabolites tended to be altered in the opposite direction as compared with the metabolic responses to excessive Zn alone. There were several up-regulated metabolites protecting plants under oxidative stress. We speculate that fullerene C₆₀ derivatives have the ability to increase antioxidant non-enzyme activity at least, improving some growth parameters. However, fullerenes did not reduce Zn transport from the root to the shoots. We concluded that the low capacity of these compounds to buffer Zn in the root zone might limit the efficiency of fullerene derivatives against Zn toxicity. Our results provide new evidence for the crucial role of Zn–fullerene interactions in the amelioration of Zn toxicity in plants. Full article

Our main goal was to determine whether the accumulation of Cd and Cu is harmful for L. perenne or whether this plant can be used in the bioremediation, e.g., of wastewaters or contaminated soils. The IC50 values (concentration at which the tested parameter is inhibited to 50% against the control) for root and shoot inhibition after 14 days showed that Cu, as an essential element for plants, was more toxic than Cd. The translocation factor (TF), which refers to metal transport from the root to the shoot, did not exceed values of 0.228 and 0.353 for Cd and Cu, respectively, indicating their accumulation mostly in the roots rather than in the shoots. The protein thiol (-SH) groups as a parameter of the increased level of reactive oxygen species did not confirm the significantly higher level of oxidative stress for Cu, which is a redox-active cation. We confirmed a statistically significant positive correlation between -SH groups and chlorophyll a (r = 0.79; p < 0.05) and chlorophyll b (r = 0.84; p < 0.01) in the presence of Cd. We concluded that bioaccumulation of the tested metals occurred mostly in the roots, and the photosynthetic pigment content in the shoots was not significantly impaired by the increased presence of Cd or Cu in the shoots. Therefore, we suggest L. perenne as a suitable candidate for the phytomining or phytoextraction of metals, mostly from wastewater, in cooperation with other plant hyperaccumulators. Full article

This study provides a seasonal and cross-shore characterization of sediments along the Ferrara coastal area (Italy). Four sites (Goro, Volano, Estensi, and Spina) were investigated through an integrated approach including textural and geochemical analyses. Surface sediments were sampled seasonally from summer 2023 to summer 2024 and analyzed to determine granulometry, major oxides composition, carbonate content, and potentially toxic element (PTE) contents. Results revealed that both grain-size and geochemistry vary seasonally and along the cross-shore profile, reflecting the combined effects of hydrodynamic forcing, sediment transport, and fluvial inputs. Elevated contents of Ce, Cr, La, V, and Zr were detected at various sites, seasons, and geomorphological zones. In some cases, the environmental quality indices applied allowed the sediments to be classified as polluted. Furthermore, some exceedances of the legal limits for Cr and V contents were observed at Goro and Volano. These pollution levels are attributable to the presence of PTE-bearing minerals originating from the source basins (geogenic sources). Overall, the results highlight the interplay between hydrodynamics and sediment provenance, emphasizing the dominance of geogenic contributions along the northern Adriatic coast, providing updated geochemical data for future monitoring and environmental management of coastal systems. Full article

Food security and human health are directly related to the condition of agricultural soils. Soil contamination by heavy metals is a global environmental problem. Lead (Pb) is a toxic and non-biodegradable element posing a significant risk to ecosystems and human health. 24-Epibrassinolide (EBR) has multiple benefits in plant metabolism, including maximizing gas exchange. In plants, exogenous application of dopamine (DOP) confers tolerance to abiotic stresses, minimizing interferences on growth. This study aimed to investigate whether the exogenous application of EBR and DOP, administered independently or jointly, can contribute to mitigating the oxidative stress and impacts on photosystem II in Pb-stressed tomato, evaluating parameters related to nutritional status, photosystem II activity, gas exchange, antioxidant enzymes, and biomass. Better results were observed with the isolated EBR application, improving the photosynthetic efficiency, as evidenced by the increases in chlorophyll contents, effective quantum yield of PSII photochemistry, photochemical quenching coefficient, and electron transport rate, resulting in a higher net photosynthesis rate. Parallelly, treatment using both plant growth regulators (DOP and EBR) promoted significant increases of 14%, 18%, 13%, and 35% in the activities of superoxide dismutase, catalase, ascorbate peroxidase, and peroxidase, contributing to the reduction in oxidative stress in photosystem II of Pb-stressed plants. Therefore, this research proves that the exogenous application of DOP and EBR, alone or in combination, attenuates the toxic effects generated by Pb in tomato plants. Full article

Nitrogen and calcium are the key elements required for plant growth. Variations in calcium concentration will affect nitrogen absorption in plants, regulate photosynthetic processes, and participate in the absorption and transport of photosynthetic products. The changes of nitrogen and calcium nutrients is conducive to alleviating the decline and mortality of Mongolian pine forests, thus contributing to the preservation of regional ecological security. In this study, an investigation was conducted into the effects of seven nitrogen-to-calcium (N-Ca) ratios (1:8, 1:4, 1:2, 1:1, 2:1, 4:1, and 8:1) on the growth and physiology of Mongolian pine seedlings through pot experiments. The results of the one-way analysis of variance indicated that variations in the N-Ca ratio could significantly affect processes such as plant height, basal diameter, biomass accumulation, and photosynthesis in Mongolian pine seedlings. A low N-Ca ratio caused calcium toxicity, resulting in reduced stomatal conductance (C_i) and a lower net photosynthetic rate (T_r). Conversely, a high N-Ca ratio led to nitrogen toxicity, decreased antioxidant enzyme activity, and adversely affected the accumulation of photosynthetic pigments and photosynthetic products. At an N-Ca ratio of 2:1, Mongolian pine seedlings not only exhibited maximized biomass and photosynthetic capacity but also demonstrated significantly elevated levels of antioxidant enzymes and content of soluble substances. In conclusion, an optimal N-Ca ratio of 2:1 existed for Mongolian pine seedlings, which significantly improved their growth and physiological characteristics. Full article

Chloride channel proteins (CLCs) are essential anion transporters involved in plant growth, osmotic regulation, and ion homeostasis. However, their genome-wide characterization in tetraploid alfalfa (Medicago sativa L.) remains unexplored. In this study, a total of 35 CLC family members were identified and underwent comprehensive bioinformatic analyses. Phylogenetic and structural analyses divided them into six subfamilies and two subclasses based on conserved residues such as GxGIPE. Members within the same subclass shared conserved domains and similar motif patterns. Analysis of duplication events indicated that 48 segmental duplications were the primary driving force behind the expansion of this gene family. Promoter analysis revealed abundant light, hormone, and stress-responsive cis-elements, suggesting multiple regulatory functions. Gene expression profiling demonstrated that salt, drought stress, and ABA treatment significantly induced the expression levels of some genes. Among them, MsCLC2 and MsCLC18 from Group c exhibited more than fivefold upregulation under both salt and drought stress, significantly higher than other members. Subcellular localization confirmed MsCLC18 on the plasma membrane, potentially regulating Cl⁻ efflux through a Cl⁻/H⁺ antiporter mechanism to alleviate Cl⁻ toxicity. These findings provide a theoretical foundation for the function study of CLC genes in alfalfa and offer new insights into the molecular evolution of polyploid plants under abiotic stress. Full article

The development of urban areas and the proliferation of impervious surfaces have significantly altered natural hydrological cycles, resulting in an increase in stormwater runoff and substantial risks to groundwater quality. This review synthesizes current research on the transport mechanisms of stormwater contaminants, including toxic elements, nutrients, pathogens, and emerging pollutants such as microplastics and pharmaceuticals, into aquifers. This study analyzes the physicochemical and biological processes that affect pollutant mobility and retention in urban soils, emphasizing the vulnerability of groundwater systems, particularly in areas with permeable soils and shallow water tables. The article evaluates a range of green infrastructure (GI) and low-impact development (LID) strategies—including rain gardens, bioswales, infiltration basins, constructed wetlands, and urban forestry—to assess how effectively they can mitigate stormwater pollution and improve groundwater protection. Case studies from North America illustrate the practical implementation and performance of GI systems, emphasizing the importance of site-specific design, monitoring, and adaptive management. The review also discusses global policy frameworks and community engagement strategies that support sustainable stormwater management. Ultimately, it advocates for an integrated, multidisciplinary approach that combines engineering, ecological science, and public policy to safeguard groundwater resources in the face of climate variability and urban expansion. Full article

Gold (Au) and silver (Ag) nanoparticles (NPs) are used for drug transport and plant protection due to their insoluble nature and unique properties. To produce health-friendly NPs, toxic solvents should be replaced with plant-based synthesis. Plants, such as alfalfa (Medicago sativa L.), release biomolecules that reduce metal ions and form nanoclusters without free radicals, showing anti-inflammatory and antioxidant properties. In this study, callus cultures of two M. sativa genotypes, ‘Kometa’ and ‘La Bella Campagnola’, were exposed to two precursors (AgNO₃ and HAuCl₄) for 24 and 48 h to assess the feasibility of biological NP synthesis. Spectrophotometry showed significant (p ≤ 0.05) changes in light absorbance compared with the control. Dynamic light scattering and zeta potential measurements indicated a change in the composition of the liquid compared with the control. To improve image quality and obtain more accurate data, transmission electron microscopy (TEM) analysis was repeated, confirming the presence of quasi-spherical nanoparticles with diameters in the range of 5–25 nm for both AuNPs and AgNPs in the callus culture extracts of both genotypes. Nanoparticle Tracking Analysis demonstrated that the AgNPs and AuNPs from both genotypes displayed polydisperse size distributions, with a mean particle size ranging from 220 to 243 nm. Elemental analysis provided clear evidence that Ag and Au were present only in treated samples, confirming effective NP biosynthesis and excluding contamination. X-ray diffraction (XRD) analysis was performed to characterise the crystalline structure; however, due to the very small particle size (5–25 nm), no clear diffraction patterns could be obtained, as nanocrystals below ~20–30 nm typically produce signals below the detection limit of standard XRD instrumentation. The novelty of this research is the cost-effective, rapid biosynthesis of quasi-spherical AuNPs and AgNPs with diverse sizes and enhanced properties, making them more eco-friendly, less toxic, and suitable for antibacterial and anticancer studies. Full article

Environmental issues have become increasingly critical and frequent in recent decades due to excessive population growth and intensified industrial and mining activities. Among the most concerning contaminants is arsenic (As), a toxic element associated with severe environmental and human health risks. This study aimed to investigate the bioremediation potential of the bacterial strains Lysinibacillus boronitolerans and Bacillus cereus, elucidating the mechanisms involved in arsenic transformation and removal under controlled conditions. The strains were cultivated in liquid medium containing known concentrations of As(III) and As(V), and the chemical forms of arsenic were analyzed using High-Performance Liquid Chromatography coupled with Inductively Coupled Plasma Mass Spectrometry (LC-ICP-MS). The production of exopolysaccharides (EPSs) and arsenite oxidase activity were also evaluated. Morphological and elemental analyses were performed using scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS). The bacterial strains exhibited significant 69.38–85.72% reductions in arsenic concentration and approximately 14–15% volatilization rates. No EPS production or arsenite oxidase activity was detected, suggesting alternative detoxification pathways. SEM-EDS analyses revealed intracellular accumulation of arsenic, while LC-ICP-MS speciation confirmed interconversion between As(III) and As(V), indicating the action of methylation-dependent detoxification and membrane transport mechanisms. The findings demonstrate that L. boronitolerans and B. cereus possess efficient arsenic resistance and transformation mechanisms, even without conventional enzymatic pathways. These strains show strong potential for use in sustainable bioremediation of arsenic-contaminated environments, particularly in regions affected by mining activities. Full article

Anthropogenic activity seriously damages the environment. Cadmium, lead, and thallium are toxic elements that are especially hazardous for nature. In polluted air, they are present in the form of microparticles 2–3 μm in size and belong to the PM_2.5 fraction. Such particles can be transported over long distances, penetrate into water and dissolve, and then enter the food chain. This poses a severe threat to human and animal health due to the bioaccumulation of metals. Therefore, it is important to study the properties of toxic metals of this size. In this work, we developed a radiation–chemical method for obtaining microparticles of cadmium, lead, and thallium corresponding to the PM_2.5 fraction and studied their properties in aqueous solutions. In the absence of oxygen, the metals do not dissolve. Over time, they agglomerate and settle. When exposed to air, the particles quickly dissolve in water, usually within a few minutes. This process involves the disappearance of small particles and a decrease in the size of larger ones. The rate of dissolution increases in the Pb-Cd-Tl series. Cadmium dissolves approximately 4–5 times faster than lead, and thallium more than 10 times faster. Acidification of water accelerates this process. Studying the properties of microparticles of heavy metals is important for assessing their migration in the environment, health risks, and developing methods for preventing pollution. Full article

Recent advances in nanotechnology, including the development of nanoparticles, thin films, and superlattices, have revitalized research in thermoelectricity by enabling independent control of thermal and electrical transport, overcoming longstanding efficiency limitations and expanding opportunities for sustainable energy generation and miniaturized device applications. Tin dioxide (SnO₂) has recently attracted increasing attention as a thermoelectric material owing to its properties, such as high-temperature chemical and structural stability, non-toxicity, and the abundance of constituent elements. Current research efforts have been directed toward enhancing its thermoelectric performance through strategies such as elemental doping, nanostructuring, strain engineering, and the development of composite systems. In this study, we investigate the effects of Mg substitutional doping on the thermoelectric characteristics of SnO₂. We synthesize undoped and Mg-doped SnO₂ nanoparticles (0.05%, 0.10%, and 0.15%) using a straightforward hydrothermal technique. The investigation of the undoped and doped materials revealed that SnO₂ possesses a tetragonal rutile-type structure, as determined through structural and morphological examination. The crystalline size of all of the samples decreases as the Mg doping concentration is increased. Hall measurement and Seebeck coefficient measurements have been employed for assessing the thermoelectric characteristics. As the Mg content increased, both the Seebeck coefficient and electrical conductivity value increased from −20 $\mathsf{\mu }$V/K to −91 $\mathsf{\mu }$V/K and 29.8 S/cm to 112.6 S/cm, confirming the presence of semiconductor behavior. The 0.15% Mg-doped sample demonstrates the highest power factor when evaluated at a temperature of 150 K, yielding a value of 9.4 $\times {10}^{-5}$ WK⁻²m⁻¹. Full article

The waste dump from the abandoned La Soterraña mine, a former mercury extraction site, contains high concentrations of mercury (Hg) and arsenic (As), which pose a significant environmental risk due to direct exposure to the environment. Given the site’s topography and slope, surface runoff has been identified as the primary mechanism for the dispersal of these toxic elements into nearby watercourses. This study quantifies the amount of Hg and As released into fluvial systems through surface runoff from the waste dump. Historical topographic data, Airborne Laser Exploration Survey public data from the National Plan for Aerial Orthophotographs (1st PNOA-LiDAR) of the Spanish Ministry of Transport, Mobility and Urban Agenda, and high-precision photogrammetric drone surveys were utilized, with centimeter-level accuracy achieved using airborne GNSS RTK positioning systems on the drone. The methodology yields reliable results when comparing surfaces generated from topographic data collected with consistent methodologies and standards. Analysis indicates an environmental release exceeding 1000 kg of mercury (Hg) and 12,000 kg of arsenic (As) between 2019 and 2023, based on high spatial resolution data (GSD = 8 cm). These findings highlight a sustained temporal contribution of chemical contaminants, which imposes serious environmental and biological health risks due to persistent exposure to toxic elements. Full article

Zinc (Zn), a naturally occurring trace element ubiquitous in the Earth’s crust, soil, and water, is indispensable for human health due to its physiological and nutritive benefits. In this scenario, Zn is pivotal for maintaining homeostasis against toxic effects exerted by heavy metals (HMs) through bioaccumulation and metabolic interference. Zinc is an enticing cofactor for miscellaneous biochemical enzymes such as Zn metalloenzymes, which mediate crucial cellular processes, including cell proliferation, protein synthesis, immune modulation, epigenetic regulation, and nucleic acid synthesis. Recently, several research studies have focused on the thorough investigation of Zn supplementation in controlling HM toxicity by competing for binding sites and boosting protective mechanisms in humans. The current article discusses the upper limits for various toxic HMs in staple crop foods, as provided by globally recognized organizations. Clinical studies recommend a daily dose of 11 mg of Zn for healthy men and 8–12 mg for women in healthy and pregnancy conditions. However, during Zn deficiency, therapeutic supplementation is expected to be adjustable, and the dosage is increased from 15 to 30 mg daily. This review discusses the dysregulation of specific Zn importers and transporters (ZIPs/ZnTs) due to their clinical significance in immune system dysfunction as well as the progression of a myriad of cancers, including prostate, breast, and pancreas. Moreover, this review emphasizes indispensable in vitro and in vivo studies, as well as key molecular mechanisms related to Zn supplementation for treating toxicities exacerbated by HMs. Full article

Crude oil exploration and transportation have led to significant soil contamination in nearby communities, yet seasonal and depth-related variations remain poorly understood. This study assessed physicochemical properties, potentially toxic elements, and polycyclic aromatic hydrocarbons in surface (0–15 cm) and subsurface (15–30 cm) soils from the Ibaa community and its pipeline Right of Way (ROW) in Rivers State, Nigeria. Samples were collected during wet and dry seasons from five locations, and analyses were conducted using standard methods. Results showed that soil temperature ranged from 27.5 to 31.2 °C, reflecting natural environmental conditions, while nitrate concentrations (1.23–3.45 mg/kg) and moisture content (14.3–23.9%) were within acceptable WHO limits. The pH values (4.61–5.72) suggested acidic conditions, particularly in the unremediated areas. Total Organic Carbon exceeded 3%, with a maximum of 6.23% recorded in the wet season, suggesting persistent hydrocarbon contamination. Phosphorus levels (2.65–6.02 mg/kg) were below the 15 mg/kg threshold. Notably, As (4.93 mg/kg) and Cd (1.67 mg/kg) concentrations exceeded the permissible WHO limits. Positive correlations were observed between As–Cd (r = 0.79), Cd–Cu (r = 0.85), and Pb–Cu (r = 0.64). Principal Component Analysis identified four components for physicochemical parameters (81.9% variance) and two for metals (82.6% variance), suggesting crude oil combustion and vehicular emissions as dominant pollution sources. Pb also correlated significantly with total PAHs in the dry season (r = 0.54, p < 0.05). The study highlights the influence of season and depth on contaminant behavior and emphasizes the urgent need for remediation and monitoring to mitigate ecological and public health risks. Full article