Search Results (2,029)

Microplastics (MPs) and potentially toxic elements (PTEs) increasingly co-occur in agricultural and peri-urban soils, yet their combined effects on adsorption, mobility, bioavailability, and phytotoxicity are highly context-dependent. This review synthesizes plant–soil evidence by focusing on the interacting roles of MP polymer type, particle size and shape, aging/weathering state, soil geochemistry, dissolved organic matter, and rhizosphere processes. Across the reported studies, MP-PTE interactions show several major directions of changes: MPs may reduce PTE lability by promoting adsorption, aggregation, or sequestration within coated surfaces and soil aggregates; conversely, they may increase PTE mobility and plant exposure when reversible binding, dissolved organic ligands, pH shifts, or particle transport deliver labile PTEs to root-active zones. Dose-dependent and biphasic responses are also common, with low MP additions sometimes attenuating stress while higher doses intensify toxicity. Quantitatively, available crop studies show that intensified co-exposure can reduce plant biomass by approximately 10.2–29.3%, depending on crop species, plant organ, MP type, dose, and PTE identity, whereas antagonistic or neutral responses are also reported under other exposure conditions. The strongest evidence currently exists for Cd and As, but this review also considers Pb, Cu, Zn, Ni, Cr, and Hg to represent chemically distinct cationic, metalloid, and redox-sensitive PTEs. Overall, MPs should not be treated only as passive contaminant carriers; they act as dynamic reactivity modifiers that can function as sinks, vectors, or indirect regulators of PTE bioavailability depending on soil and rhizosphere boundary conditions. Full article

With the continuous expansion of ultra-deep and deep well drilling toward complex geological formations, the performance stability of water-based drilling fluids and wellbore stability under ultra-high temperature and high-salinity conditions have become critical challenges. High temperature and salt contamination can induce the degradation or failure of drilling fluid additives, while the development of pores and fractures in complex formations further increases the risk of filtrate invasion. Conventional polymer and inorganic plugging agents often suffer from insufficient thermal stability, poor salt tolerance, or limited adaptability to complex pore structures. In this study, an organic–inorganic hybrid gel microsphere plugging agent (HGP) with a core–shell structure was developed by in situ polymerization of AMPS, styrene (St), and sodium styrene sulfonate (SSS) on KH570-modified nano-SiO₂. The hybrid microspheres consisted of a rigid SiO₂ core and a flexible polymer shell, providing synergistic thermal stability, mechanical strength, and deformation capability. Structural characterization confirmed the successful formation of the designed organic–inorganic hybrid structure. After aging at 240 °C, HGP maintained stable morphology and dispersion characteristics, while exerting minimal influence on drilling fluid rheological properties. The addition of 3 wt% HGP reduced API fluid loss by approximately 30% and decreased sand bed invasion by approximately 50% after high-temperature aging. Under 35 wt% NaCl and 5 wt% CaCl₂ contamination, HGP maintained effective filtration control, reducing fluid loss by more than 50% compared with the base fluid. Furthermore, HGP achieved core plugging efficiencies above 94% and reduced mud cake permeability by over 70%, demonstrating superior plugging performance compared with polymer microspheres NF-1 and SiO₂ particles. The enhanced performance was considered to arise from the synergistic effects of stable dispersion, pore-throat bridging, deformation filling, and structural stabilization. This study provides a rigid–flexible hybrid strategy for designing high-performance plugging agents for ultra-high temperature and high-salinity water-based drilling fluids. Full article

Atmospheric microplastics are increasingly recognized as mobile particulate contaminants that can be emitted, resuspended, transported, and deposited across indoor, terrestrial, marine, high-altitude, and remote environments. However, reported abundances and particle characteristics remain difficult to compare because studies differ in sampling design, reporting units, particle-size limits, contamination control, and polymer identification. This review combines concise bibliometric mapping with a critical narrative synthesis. A Web of Science Core Collection search for 2000–2024 retrieved 356 English-language articles and reviews, of which 280 met the eligibility criteria. Publication output increased rapidly after 2020. Co-citation and keyword analyses identified three major themes: occurrence, transport, and deposition; sampling and analytical characterization; and exposure and potential ecological and health implications. The synthesis shows that active air sampling and passive deposition collection measure different atmospheric processes, while inconsistent blank correction, recovery assessment, and polymer confirmation limit inter-study comparability. Field observations and modelling support long-range transport and the importance of particle morphology, but quantitative source attribution remains uncertain. Current evidence supports inhalation exposure and biological plausibility, yet is insufficient to establish population-level risks or causal links with specific diseases. Future research should prioritize harmonized monitoring, stronger QA/QC, improved detection of small particles and nanoplastics, and integrated transport–exposure assessment. Full article

Honey bee colonies play a vital role in ecosystem stability and global food security. Together with bumble bees and other wild bee species, they form a diverse pollinator community that is particularly vulnerable to environmental pollution. Among stressors, environmental xenobiotics including heavy metals, metalloids, pesticides, polycyclic aromatic hydrocarbons, per- and polyfluoroalkyl substances, and emerging contaminants such as microplastics pose a growing concern due to their persistence, bioaccumulation potential and capacity to trigger oxidative stress and interact with pathogens, nutritional stress and climate-related extremes. The antioxidant defense system, encompassing enzymatic components (superoxide dismutase, catalase, glutathione-dependent enzymes and glutathione-S-transferase) and non-enzymatic antioxidants, represents a key protective mechanism, and its disruption leads to redox imbalance, immunosuppression, and behavioral alterations that can reduce honey bee colony vitality. This review synthesizes current knowledge on the sources, exposure pathways and toxicological effects of major environmental xenobiotics on the antioxidant defense systems of honey bees, with particular emphasis on oxidative-stress biomarkers for early detection of sublethal impairment in field and experimental settings. Where available, evidence from bumble bees and other wild bees is considered to place findings in a broader pollinator-health context and to highlight taxa-specific sensitivities. Work should now concentrate on a validated core panel of redox biomarkers, on chronic multi-stressor exposures that include PFAS and plastic particles, and on biomarker baselines for bumble bees and solitary bees tied to colony- or population-level endpoints. Full article

Asbestos contamination in drinking water remains an underexplored environmental issue despite the widespread historical use of asbestos-cement materials in water infrastructure and buildings worldwide. This study evaluated the occurrence and removal of asbestos fibers throughout the drinking water treatment chain in Cartagena de Indias, Colombia, from source contamination to household filtration. Synthetic asbestos-contaminated water prepared from asbestos-cement roofing materials was treated using coagulation–flocculation with aluminum sulfate, a pilot-scale conventional treatment train, membrane filtration, and household point-of-use filtration systems. Asbestos quantification and mineral identification were performed using transmission electron microscopy (TEM), with results reported as million fibers per liter (MFL). Coagulation–flocculation achieved the highest removal efficiencies, reaching up to 99.8% at aluminum sulfate dosages between 35 and 45 mg/L. The pilot-scale treatment system substantially reduced asbestos concentrations, with granular filtration representing the principal removal barrier. Membrane filtration exhibited moderate and highly variable performance, with an average removal efficiency of 44.7%, whereas household filters showed inconsistent behavior and occasional concentration peaks associated with possible breakthrough or remobilization processes. The results demonstrate that asbestos removal is strongly governed by the treatment mechanism, with particle destabilization and aggregation outperforming technologies relying exclusively on physical retention. These findings support the progressive replacement of asbestos-containing water infrastructure as the primary long-term preventive strategy, complemented by targeted monitoring and optimized asbestos-removal treatment where fiber contamination is detected or a risk of release from legacy materials exists. Full article

Microplastics (MPs), defined as plastic particles smaller than 5 mm in diameter, are an emerging class of environmental contaminants of global concern. As the “Water Tower of Asia” and a critical global ecological barrier, the environmental condition of the Qinghai–Tibet Plateau has a direct influence on the ecological security of major river systems and the well-being of populations downstream. MPs have now been detected across multiple environmental compartments on the plateau, including soils, water bodies, and glaciers. Given the fragility and ecological uniqueness of the region, systematic investigation of plastic pollution here is essential for safeguarding its ecological security. Based on current research, existing data on MP pollution across the Qinghai–Tibet Plateau are reviewed and synthesized. Evidence suggests that the abundance of MP varies significantly across different environmental media in various regions and is influenced by multiple factors. Two major potential sources are identified: local anthropogenic activities and transboundary inputs via atmospheric transport and other pathways. The unique environmental conditions of the region, such as intense ultraviolet radiation, large day–night temperature variation, and frequent high-wind events, provide a distinctive setting for the migration, dispersion, transformation, and degradation of MPs across environmental matrices. Understanding the distribution, sources, and migration patterns of microplastics on the Qinghai–Tibet Plateau will help facilitate sustainable environmental management, ecosystem conservation, and pollution control in these fragile high-altitude regions. Full article

Microplastics are plastic particles smaller than 5 mm that have become a growing environmental concern due to their persistence and widespread distribution. They originate from diverse sources, including laundry detergents, vehicle tires, cosmetic microbeads, and the degradation of larger plastics through ultraviolet radiation and saline exposure. This systematic review was conducted following the PRISMA guidelines to summarize current knowledge on the environmental and human health effects of microplastics. A comprehensive literature search was performed in ScienceDirect, PubMed, Web of Science, and Google Scholar databases, yielding 2694 initial records. After applying exclusion criteria and removing duplicates, 111 studies were selected for full reading, and 54 articles were ultimately included in the analysis. The results reveal that microplastics can absorb and release pollutants, leading to the contamination of water and soil and enabling them to enter the food chain, thereby posing potential risks to both ecosystems and human health. However, significant discrepancies were found among the databases regarding the amount and quality of available data, highlighting the need for standardized research approaches. In conclusion, understanding the sources, distribution, and impacts of microplastics is crucial to developing strategies to mitigate their release, and further research is essential to assess their long-term effects and to guide environmental policy. Full article

In this work, a comprehensive analysis of the relationship between photoluminescent, thermo-oxidative, and photocatalytic (upon simulated sunlight exposure) properties of ZnO powders is performed. The correlation between the X-ray diffraction and microscopic data is studied. ZnO powders of various sizes and morphologies were used: pseudo-spherical nanoparticles (30–50 nm), submicron faceted crystallites (100–500 nm), and plate- and rod-like microstructures (up to 20 μm). The mean specific surface area values were 32 m²/g, 3.8 m²/g, and 2.6 m²/g for pseudo-spherical nanoparticles, submicron faceted crystallites, and plate- and rod-like microstructures, respectively. According to the XRD data, microstresses and carbon-based impurities were present in ZnO nanoparticles, which is characteristic of nanomaterials synthesized at low temperatures. According to the photoluminescence spectroscopy data, the emission in ZnO was reduced due to high defectiveness, and characteristic emission bands indicated the presence of organic impurities. Upon long signal registration times, an intensive luminescence band with an effective maximum at 579 nm occurred, which indicated the presence of long-term components exhibiting decay times τ ~300 μs. According to the XRD data, the crystal structure parameters of ZnO submicro- and microparticles were close, with no impurities present. In their photoluminescence spectra, pronounced UV and defect-related bands were present with intensity ratios of 11.6 and 6.88, respectively. The decrease in the UV and defect-related luminescence band intensity ratios indicates deviation from the stoichiometry toward an increased Zn over oxygen content. At long signal registration times, in submicron ZnO particles, a luminescence band with maxima at 425 and 490 nm is present, which decays rapidly. An emission band in the 530 nm region is also present, which decays for ≤80 μs, and a weak long-wavelength emission decaying for ~100 μs. At long delay and strobe times (up to milliseconds), only an emission in the 460 nm region is observed, which we connect to the triplet–singlet transition of a defect center (F*, F⁺*). At lower intensities, an emission connected to the surface contamination by organic impurities is observed. In photoluminescence spectra of ZnO microparticles, no long-wavelength emission components are observed. However, upon immersing into methylene blue solution, a modification of the surface and UV region of the spectra is observed with signs of charge carrier recombination rate acceleration. It is shown that the catalytic action of ZnO powders in polyethylene thermo-oxidation processes is determined by a combination of factors. In addition to dispersity and concentration, which are the key parameters, the morphology of ZnO particles, the presence of impurities, the surface state, and the distribution of active sites have a significant influence on catalysis. It has been experimentally demonstrated that these secondary factors can markedly affect the rate of radical formation in polyethylene films and alter their resistance to oxidation. ZnO nanoparticles exhibited low catalytic activity in both photocatalysis (rate constant 0.146 min⁻¹) and thermocatalysis due to the high defect density of the crystallites and the presence of carbon-containing impurities. Submicron ZnO particles, owing to a high carrier generation rate and suppressed recombination (via trapping), demonstrated the highest photoactivity (rate constant 0.729 min⁻¹). Submicron ZnO particles exhibit a catalytic effect on the thermo-oxidation of polyethylene (PE films); however, at concentrations above 8 wt.% a transition to an inhibiting effect is observed. ZnO microparticles catalyzed the oxidation of PE films over a broader concentration range (1–12 wt.%), with oxidation inhibition observed only at 18 wt.%. At the same time, they demonstrated moderate photocatalytic activity (rate constant 0.256 min⁻¹). These characteristics of the samples correlate with data obtained by microscopy, photoluminescence spectroscopy, and X-ray diffraction analysis. Full article

Background/Objectives: Microplastics (MPs) are emerging environmental contaminants with potential implications for human health. Experimental studies suggest that MPs accumulate in the liver and promote inflammatory and fibrotic changes, but evidence from human tissues remains limited. This study investigated the presence of suspected MP-like particles in post-mortem human liver tissue and their associations with clinical, biochemical, hematological and histopathological parameters. Methods: Post-mortem liver tissue samples were collected from 55 adults. Suspected MP-like particles were extracted using hydrogen peroxide digestion, filtration, Nile Red staining and image-based quantification. Histopathological evaluation assessed inflammation, fibrosis, necrosis and fatty liver degeneration. Polarized light microscopy was used as a supportive morphological assessment method. Statistical analyses included Mann–Whitney U tests, Fisher’s exact tests and Spearman correlation analysis. Results: Detectable hepatic suspected MP-like particles were identified in 9 of 55 individuals (16.4%). Individuals with detectable suspected MP-like particles had significantly lower alanine aminotransferase (ALT) levels and leukocyte counts. The hepatic suspected MP-like particle burden showed weak positive correlation with liver fibrosis and inflammation and weak inverse correlation with ALT levels and leukocyte count. Fisher’s exact test showed that liver fibrosis and liver inflammation were significantly associated with detectable hepatic suspected MP-like particles, with higher unadjusted odds observed in the corresponding 2 × 2 contingency tables. No statistically significant associations were found for liver necrosis or fatty liver degeneration. Conclusions: Detectable suspected MP-like particles were identified in post-mortem human liver tissues and were more closely associated with fibrotic and inflammatory histopathological changes than with routine biochemical abnormalities. Larger studies using standardized detection methods are needed to confirm these results. Full article

Microplastics have emerged as one of the most widespread and significant environmental pollutants, occurring in aquatic and terrestrial ecosystems, the atmosphere, food, and living organisms. Given the rapid expansion of research in this field, a comprehensive synthesis of the current state of knowledge is warranted. The aim of this study was to map the available literature on microplastics, with particular emphasis on advanced identification and characterisation techniques, environmental transport and transformation processes, life cycle assessment, and remediation strategies. This scoping review was conducted in accordance with the PRISMA-ScR guidelines using publications retrieved from the PubMed, Scopus, Web of Science, and Google Scholar databases. The analysis demonstrated substantial advances in analytical methodologies, particularly spectroscopic and microscopic techniques, enabling the accurate characterisation of micro- and nanoplastic particles. It also highlighted the complex mechanisms governing the transport and transformation of microplastics across environmental compartments, as well as their important role as vectors of chemical contaminants. From a systems perspective, life cycle assessment of plastics was identified as an essential tool for evaluating their environmental impacts. Current mitigation approaches, including filtration technologies, wastewater treatment processes, and biological remediation strategies, were also reviewed, along with their limitations and potential for future development. This review identifies the lack of standardised analytical methodologies and the limited capability for nanoplastics detection as two major challenges hindering the global harmonisation of microplastics research. The findings emphasise the need for further interdisciplinary studies and the implementation of integrated strategies encompassing the entire life cycle of plastics to effectively reduce microplastics emissions and mitigate their environmental impacts. Full article

Ambient exposure to fine particulate matter (PM_2.5) remains a critical global public health concern; however, the speciation and bioaccessibility mechanisms of particle-bound heavy metals within the lung environment are still insufficiently understood. In particular, the role of soluble and insoluble metal species in simulated lung fluids requires further clarification. Road dust, a major contributor to PM_2.5, contains heavy metals that pose significant inhalation risks, leading to oxidative stress, DNA damage, and systemic toxicity. This study investigated the contamination characteristics, bioaccessibility, pollution level, and speciation of heavy metals in PM_2.5-fractionated road dust (PM_2.5RD) collected from Karachi (a megacity with >27 million inhabitants) and Shikarpur (a medium-sized city of ~0.3 million) in Pakistan. A grid-based sampling approach was applied across four functional zones (residential, school, hospital, and office), yielding 48 samples. Inhalation bioaccessibility was evaluated using artificial lysosomal fluid (ALF; pH 4.5, 37 °C, 24 h), revealing moderate bioaccessibility of Cr, As, and Pb. Pollution status was assessed using contamination factor (CF), integrated pollution index (IPI), pollution load index (PLI), and potential ecological risk index. Geochemical modeling with PHREEQC 3.0 and Visual MINTEQ 3.1 was employed to simulate metal speciation, release behavior, and mineral saturation states. Overall, this study provides mechanistic insights into speciation-driven toxicity of As, Pb, and Cr in simulated lung environments, offering a scientific basis for improved risk assessment and regulatory strategies for PM_2.5-associated metal exposure. Full article

Long-term bridge temperature monitoring data are often affected by random noise, outliers, and sensor drift, which may reduce the reliability of structural thermal-response analysis. This study proposes a collaborative framework based on an improved adaptive cubature Kalman filter (IACKF) for multi-anomaly mitigation. First, the process- and observation-noise covariance matrices are updated online using innovation and residual statistics to suppress time-varying noise. Second, a dual-Gaussian contaminated observation model is incorporated to develop an outlier-resistant improved adaptive cubature Kalman filter (OR-IACKF) for isolated and patch-type outliers. Third, an improved particle swarm optimization–backpropagation–IACKF (IPSO-BP-IACKF) scheme is used to predict a drift-free reference from adjacent monitoring points and recursively estimate sensor drift. The framework is evaluated using simulated data, constant-temperature chamber measurements, field-monitored bridge data, and a jointly contaminated dataset. The results indicate that the staged framework improves the mitigation of different anomaly types while maintaining relatively stable performance under different parameter settings. The proposed method provides a practical data-processing approach for long-term bridge structural health monitoring. Full article

MP contamination in drinking water is an emerging public health concern, yet standardized analytical workflows and exposure assessments remain limited and fragmented. This study provides an exploratory assessment of MP exposure through drinking water, combining particle-resolved analysis with consumption-based estimates. Laser Direct Infrared (LDIR) spectroscopy was applied within the analytical workflow to characterize MPs across different drinking water supply types. Ten drinking-water samples (five bottled, two tap, two public dispensers, and one office dispenser) were analyzed within a 10–500 µm size window, and particle-resolved results were combined with a consumption survey to support preliminary exposure estimates. MPs in the 10–150 µm range were detected in six of ten samples, while tap waters and all blanks were particle-free, supporting analytical robustness. Bottled waters showed the highest MP abundances (6–148 particles L⁻¹) and mass concentrations (0.03–22.4 µg L⁻¹). Particle-size distributions were right-skewed and dominated by particles ≤ 30 µm. PET, PU, PA, and ABS predominated, consistent with packaging and dispensing origins. EDI estimates for bottled-water consumers ranged from 0.1008 to 0.3023 µg kg-bw⁻¹ day⁻¹ across three consumption scenarios (1–3 L day⁻¹). Despite the limited sample size, the results support LDIR for source discrimination and exposure screening, providing a basis for future research. Full article

Antibiotic contamination of water, particularly by tetracycline (TC), requires effective and sustainable treatment strategies. In this study, CoFe₂O₄ nanoparticles were synthesized using lime juice as a natural stabilizing agent and combined with ZnO to obtain a ZnO/CoFe₂O₄ nanocomposite for visible-light-driven TC degradation. Complementary characterization confirmed the coexistence of ZnO and CoFe₂O₄ without detectable secondary phases, with predominantly spherical and irregular particles. The composite exhibited ferromagnetic behavior, suggesting potential magnetic recovery, and showed broader visible-light absorption and a reduced band gap of 3.05 eV compared with 3.23 eV for ZnO. Although its specific surface area and pore volume were lower than those of CoFe₂O₄, the nanocomposite displayed the highest photocatalytic performance. Under the optimized conditions of pH 6, 20 mg L⁻¹ TC, and 1 g L⁻¹ catalyst, 96.8% degradation was achieved after 120 min, with a pseudo-first-order rate constant of 0.029 min⁻¹. The degradation efficiency remained 88.3% after five cycles. Scavenger experiments identified photogenerated holes (h⁺) and hydroxyl radicals (·OH) as the dominant reactive species. The improved photocatalytic activity may be associated with interfacial interactions between ZnO and CoFe₂O₄, suggesting that the green-synthesized nanocomposite has potential as a visible-light photocatalyst for TC degradation under the investigated conditions. Full article

After in situ leaching of weathered crust elution-deposited rare earth ore (WREO), large amounts of residual ammonium (RA) salts remain in the ore body and slowly release, causing persistent ammonia-nitrogen pollution in surrounding waters. This study proposes using magnesium chloride for in situ elution remediation of closed mines. Column experiments were conducted to evaluate the effects of eluent concentration, liquid–solid ratio, flow rate, pH, and temperature on residual ammonium removal, and a kinetic model was established based on the shrinking unreacted-core model. The results show that increasing Mg²⁺ concentration, temperature, or flow rate accelerates the eluting rate, with temperature being the most influential. A higher liquid–solid ratio in the tested range could enhance the elution efficiency of residual ammonium, but it will substantially raise the production cost. Weakly acidic pH 4–6 favors the reaction, while alkaline conditions inhibit it. Kinetic analysis indicates inner particle diffusion control, with an activation energy of 6.03 kJ/mol and a reaction order of 0.3009. Under optimal conditions of 0.1 mol/L Mg²⁺, 2:1 liquid–solid ratio, 0.6 mL/min, pH 4–6 and room temperature, elution efficiency reaches 95.45%. This work provides theoretical and technical support for green remediation of historical ammonium contamination in WREO. Full article