Search Results (209)

Coal mining critically affects Shanxi’s economy and national energy security in China, whereas mine water significantly influences regional water quality and ecological stability. However, studies on pollution characteristics and health risks of fluoride and potentially toxic elements (PTEs) remain limited, especially comparative analyses between raw mine water and treated mine drainage. This study comprehensively analyzed the pollution characteristics of fluoride and PTEs, along with water quality evaluation, ecological risks, and human health risks associated with raw mine water and mine drainage. Fluoride concentrations in raw mine water from several mines exceeded the WHO guideline limit of 1.5 mg/L, whereas those in mine drainage were below the WHO standard. The total hazard index (THI) of fluoride in both water types was unacceptable (THI > 1). For PTEs, only arsenic in raw mine water exceeded the Grade III groundwater standard, while all PTEs in mine drainage met standards. Total health risk of PTEs in raw water was approximately one order of magnitude higher than in mine drainage, and both exceeded acceptable levels, mainly contributed by carcinogenic elements, particularly arsenic. These results underscore continuous monitoring and targeted control of arsenic are still required for safe utilization of coal mine water. Full article

Zinc processing generates large volumes of tailings enriched with potentially toxic elements such as zinc, lead, arsenic, and antimony, creating environmental challenges. Conventional disposal in tailings dams is associated with land occupation, contamination risks, and geotechnical concerns, reinforcing the need for more sustainable management strategies. This study presents a bibliometric and semi-systematic review of alkali-activated binders for the stabilization and solidification of zinc mine tailings, based on nine studies published between 2019 and 2026. The results indicate that this is a recent and expanding research field, with a marked concentration of studies in China. Current research mainly focuses on the links between microstructure, heavy metal immobilization, and mechanical performance. Alkali-activated systems, commonly based on blast furnace slag, fly ash, and coal gangue, can produce dense matrices with compressive strengths of up to 100.77 MPa and high immobilization efficiency. Their performance is largely governed by the type of reaction products formed, particularly calcium silicate hydrate, calcium aluminosilicate hydrate, and sodium aluminosilicate hydrate gels, which control microstructural development and stabilization mechanisms such as encapsulation, structural incorporation, and secondary phase formation. Overall, the reviewed studies suggest that alkali-activated binders have potential as alternative binders to Portland cement for the management and valorization of zinc mine tailings. Full article

Arsenic (As) and lead (Pb) contamination of soils surrounding abandoned mines threatens environmental safety and limits their potential for agricultural reuse. Although calcium-based materials are widely used for heavy metal stabilization, integrated assessments of shell-based stabilizers considering both contaminant immobilization and soil functionality remain limited. This study assessed the effectiveness of shell-based stabilizers derived from fishery by-products, namely cockle and manila clam shells, which are primarily composed of calcium carbonate (CaCO₃), and their influence on soil health and crop safety. The shells were processed into natural and calcined forms and applied to As- and Pb-contaminated soils. Stabilization was evaluated using extraction tests, soil health indicators, and a lettuce cultivation experiment. The natural and calcined shell treatments reduced the extractable concentrations of As and Pb. Calcined shells exhibited higher immobilization efficiency due to Ca–As precipitation and the formation of calcium silicate hydrate and calcium aluminate hydrate phases. However, these treatments induced excessive alkalinity, negatively affecting soil chemical properties and overall soil functionality. In contrast, natural shell treatments provided a more balanced performance by reducing heavy metal mobility while maintaining favorable soil conditions. Lettuce grown under the stabilization–cover soil system showed at least an 87.4% reduction in As concentration compared with the control, while Pb was not detected in any stabilization-cover soil treatment. These results highlight the importance of evaluating shell-based stabilizers within an integrated framework that considers both contaminant immobilization and soil health. Full article

Copper smelting dust is a heterogeneous by-product of pyrometallurgical processing containing sulfate- and arsenic-bearing components, which accounts for its high chemical stability and environmental hazard. In this context, mechanochemical activation is considered a promising approach for initiating structural and phase transformations in such systems. The aim of this study was to investigate the effect of high-energy planetary milling in the “dust–Na₂S” and “dust–Na₂S–NaOH” systems on changes in the phase composition of arsenic-bearing dust. The samples were prepared by dry mechanochemical activation in a planetary mill for 15 and 30 min with varying reagent contents. According to X-ray diffraction analysis, PbSO₄ and ZnSO₄·H₂O remain the major phases in the binary system, while the formation of elemental sulfur (S₆) and the arsenic sulfide phase (As₄S₄) is observed against a decrease in the As₂O₃ content. In the presence of NaOH, a more pronounced redistribution of arsenic species is observed, accompanied by the appearance of a Na-containing As–O–S phase, preliminarily identified as Na₃AsO₂S₂, and a further decrease in the proportion of As₂O₃. Thermodynamic analysis indicates the energetic favorability of arsenic sulfidation when the oxidative contribution of the air atmosphere during milling is taken into account. The obtained results refine the possible mechanochemical pathways of arsenic transformation and may be used to substantiate preliminary activation regimes prior to subsequent leaching. Full article

Microbiome dysbiosis has become recognized as an important interface connecting environmental exposures to chronic inflammatory and degenerative diseases. Although prior research has largely considered heavy metals as biomarkers of exposure and toxicity, their function as ecological modulators of host-associated microbial communities remains underexplored. The oral cavity is a distinct exposome–microbiome interface where environmental, behavioral, and intraoral metal sources converge and interact with structured biofilms and mucosal immunity. This review adopts an ecological systems perspective, interpreting chronic low-dose exposure to metals such as cadmium, lead, mercury, nickel, chromium, arsenic, and aluminum as a sustained selective force on oral microbial networks. A resilience–threshold model is proposed in which cumulative metal pressure progressively diminishes microbial community stability, alters network topology, and drives transitions toward persistent dysbiosis. These modifications are further reinforced by oxidative–inflammatory feedback loops at the host–microbiome interface, facilitating a self-sustaining ecological imbalance. Sketching on insights from microbial ecology, environmental toxicology, and host response biology, this review presents a framework that links metallomic patterns to microbial restructuring, redox imbalance, immune activation, and regulatory adaptation. The analysis emphasizes ecological perturbations from stable dysbiotic states and identifies key methodological limitations that currently restrict causal inference. By conceptualizing heavy metals as active ecological drivers rather than passive exposure indicators, this work establishes a foundation for understanding microbiome-mediated disease susceptibility within an exposome-informed systems biology framework. Full article

Fungal infections represent an escalating global health challenge due to their increasing incidence, the emergence of multidrug-resistant pathogens, and the limited development of new antifungal agents. Therapeutic efficacy is compromised by mutations in drug targets, overexpression of efflux pumps, alterations in the ergosterol biosynthetic pathway, biofilm-associated tolerance, and extensive genomic plasticity. The growing prevalence of antifungal resistance and the limited availability of effective therapeutic options highlight the urgent need to strengthen epidemiological surveillance and accelerate research into innovative therapeutic strategies. In this review, we discuss the potential of lipid-based drug delivery systems (LDDSs) as a versatile strategy to optimize antifungal administration and overcome resistance mechanisms. Liposomes (LPs), solid lipid nanoparticles (SLNs), nanostructured lipid carriers (NLCs), and lipid nanoparticles (LNPs) offer high biocompatibility, efficient encapsulation of hydrophobic compounds, structural stability, and controlled drug release. Their nanoscale properties facilitate penetration into biofilms, promote intracellular uptake, and reduce the impact of efflux-mediated drug extrusion, thereby improving cellular penetration and circumventing resistance pathways. In addition, LDDSs increase bioavailability, reduce toxicity, and promote drug accumulation within poorly accessible tissue compartments. Overall, LDDSs represent a promising approach to expand the therapeutic arsenal against both superficial and invasive fungal infections, particularly those caused by multidrug-resistant pathogens. Full article

(1) The growing interest in the use of natural and sustainable ingredients highlights the investigation of vegetable oils in dermato-cosmetic applications. In this context, the vegetable oil obtained from walnut (Juglans regia L.) is of actual interest due to its composition rich in unsaturated fatty acids. The aim of the present study was to investigate and characterize walnut oil from a physicochemical, structural, and rheological point of view. (2) The oil was obtained by a cold pressing process from walnut seeds, with a yield of about 51.03 ± 1.41%, and subsequently analyzed by complementary methods. (3) The results show an acceptable physicochemical profile, characterized by appropriate values of density, pH, and spreadability. The oxidative stability indicated a moderate resistance to degradation, specific to oils rich in polyunsaturated fatty acids. Fourier infrared transform spectrometry (FTIR) analysis confirmed the presence of functional groups characteristic of triglycerides, without indications of advanced oxidation, and atomic force microscopy (AFM) investigations revealed a heterogeneous morphology. The rheological properties indicated a pseudoplastic behavior, favorable for topical application. The determination of heavy metals confirmed the safety of the raw material for the intended dermato-cosmetic use. While arsenic levels were slightly above the strict Codex Alimentarius limits for foodstuffs, all values remained within the safety ranges established for cosmetic ingredients. A total of six fatty acids were found in cold-pressed walnut oil, determined using GC-MS methods. The number of compounds identified in the silylated sample was found to be 17. The antioxidant activity determined using DPPH and ABTS methods was generally considered good and relatively stable over time. The measured sun protection value (SPF) demonstrates a favorable capacity to act as a photoprotective ingredient against ultraviolet (UV) radiation. (4) Overall, the results demonstrate that walnut oil presents adequate physicochemical and structural properties, supporting its further use as a potential cosmetic raw material. Full article

The preservation of hydrobiological diversity is essential to ensuring the stability of the food chain and the sustainable development of high-Andean basins, which face increasing vulnerability to anthropogenic factors such as the construction of dams and reservoirs. In this study, multiple regression models, both linear and nonlinear, were developed to predict the Shannon–Wiener (H′) and Pielou (J′) indices of periphyton and macrobenthos using 21 water quality parameters and concentrations of nine metals in sediments. Samples of macrobenthos and periphyton were collected at seven monitoring stations during the dry and wet seasons between 2014 and 2025. For the analysis, linear regression models were compared with nonlinear machine learning models, specifically Gradient Boosting and Random Forest. Principal component analysis (PCA) revealed that variability of the basin’s ecosystem is dominated by geogenic factors (conductivity, boron, chlorides, and arsenic) and thermal influence. The Gradient Boosting model demonstrated superior predictive capacity (R² = 0.768 for macrobenthos) compared to linear models (R² = 0.354), successfully capturing the nonlinear responses of biota to stressors such as arsenic in sediments and temperature. It is concluded that natural chemical anomalies in the Titire River act as severe ecological filters, and that artificial intelligence shows promising results in the exploration of new applied tools for environmental management in extreme altoandine ecosystems. Full article

This article presents the results of developing a hydrometallurgical method for processing polymetallic sublimates containing arsenic, zinc, copper, and lead. Using sublimates from “BalkhashPolymetal” LLP (Kazakhstan) as an example, the optimal conditions for sulfuric acid leaching were determined as follows: t = 80–85 °C, H₂SO₄ = 25 g/dm³, τ = 60 min. Under these conditions, extraction of arsenic was 93%, zinc 80%, and copper 42% was achieved. Iron(II) hydroxide was used to remove arsenic from the solution, which made it possible to reduce the residual As content in the solution to 0.02 g/L and return approximately 97% of copper to the process cycle. Eh–pH analysis of the Fe–As–Cu–H₂O system confirmed the thermodynamic stability of Fe(II/III) arsenates in the selected pH range 3–5. The obtained results can be used to develop safe and resource-saving technologies for processing technogenic raw materials. Full article

Arsenic contamination, mainly in the arsenate (As(V)) form, continues to pose a serious threat to groundwater quality worldwide due to its long-term stability and toxicity at very low levels. Herein, we demonstrate, for the first time, a three-dimensional graphene oxide-based nanocomposite composed of Cu nanoparticle-doped, amino-functionalized UiO-66 (Cu/UiO-66-NH₂) anchored on a graphene oxide framework (Cu/UiO-66-NH₂@GO) as a novel and efficient nanosorbent for the rapid removal of As(V) in groundwater-like solutions. The nanocomposite was characterized by SEM and HRTEM to confirm the hybrid structure and by XRD, N₂ adsorption–desorption isotherms, and XPS to investigate crystallinity, porosity, and surface chemistry. The derived material exhibited a highly dispersed morphology and performed rapid arsenate solid-phase extraction to attain equilibration within 10 min and was effective for a wide pH range of 2–11. The best fit for the kinetic profiles was provided by the pseudo-second-order model. Interestingly, the maximum adsorption capacity of 747.9 mg g⁻¹ at pH 6.8 was achieved, demonstrating the benefits of the complementary pairing of dispersive GO sheets and Zr-MOF adsorption domains with Cu-derived active sites. Mechanistically, the enhanced uptake is ascribed to a combination of effects, including electrostatic pre-concentration, ligand exchange, and inner-sphere complexation at metal-oxo nodes; spectroscopic analysis (XPS and FTIR) suggests that the majority of arsenate is immobilized via a strong Zr-O-As bond at coordinatively unsaturated Zr centers, which is in line with t-ZrO₂-like surface domains formed within the nanocomposite. The embedded GO support inhibits further framework interpenetration and enhances active site availability and mass transport, leading to fast and high-capacity arsenate capture in groundwater samples with related conditions. Taken together, this work presents a powerful design concept that integrates unique GO-supported, Cu-modified UiO-66-NH₂ with Zr-O binding motifs to afford high-rate remediation nanocomposites, providing an excellent platform for next-generation arsenate remediation materials. Full article

Arsenic pollution is a prevalent challenge worldwide due to extensive use dating back thousands of years, and the pentavalent species arsenate (As(V)) is of particular interest because it predominates in oxygenated groundwater. Metal–organic frameworks (MOFs), characterized by their high surface area and tunable surface chemistry, have emerged as promising adsorbents for its rapid and efficient removal. This study systematically evaluated the adsorption performance, physicochemical properties, and regeneration behavior of monometallic Fe-BTC MOF and bimetallic Fe/Cu-BTC for As(V) removal under application-relevant conditions. Fe-BTC exhibited the highest adsorption capacity of As(V) (117.5 mg g⁻¹), whereas Fe/Cu-BTC showed a lower capacity (74.6 mg g⁻¹). Adsorption in tap water decreased slightly for both materials (19–23%), indicating mild competition from coexisting ions. The adsorption behavior followed the Freundlich model, indicating competitive occupation of high-energy sites on Fe-BTC. In contrast, the surface heterogeneity of Fe/Cu-BTC remained unchanged, highlighting its robust characteristics. Adsorption was strongly pH-dependent, reaching a maximum at neutral pH, and regeneration experiments identified ethanol as the most effective desorption agent for Fe-BTC, enabling reuse. Metal-leaching analysis confirmed superior Fe-BTC MOF stability and minimal leaching, whereas Fe/Cu-BTC instability demonstrated risk of secondary Cu contamination. Overall, these findings establish that Fe-BTC and Fe/Cu-BTC MOF are effective for As(V) adsorption, but Fe-BTC outperforms Fe/Cu-BTC as a practical adsorbent. Significantly, Fe-BTC performance is strongly influenced by water matrix composition and regeneration solvent, highlighting considerations for real-world applications. Full article

Arsenic (As)-enriched soils in abandoned mining areas pose persistent environmental risks, yet the temporal evolution of remediation is rarely evaluated. In this study, a two-year field monitoring program was conducted at a severely As-contaminated abandoned gold mine in Guangdong Province, China, to examine the temporal dynamics of soil properties and As behavior under different remediation strategies. Three representative slopes were investigated: slope A (slope reshaping and revegetation), slope B (terraced engineering interception), and slope C (an area influenced by acidic water bodies). The results showed that both total and available As at slopes A and B exhibited a similar pattern of initial increase followed by decline and stabilization, indicating a clear temporal scale for remediation effects. Slope A exhibited greater spatial variability, whereas slope B showed relatively minor fluctuations, suggesting that terraced engineering measures contributed to enhanced As stability. In contrast, slope C had lower total As but a higher proportion of available As prior to remediation due to the acidic conditions. Following remediation, both total and available As at slope C decreased markedly and remained stable for about six months; however, a rebound trend was observed after approximately 1.5 years, indicating the time-limited effectiveness of passivation treatments. Specifically, total As at slope C decreased from 22,916 to 4011 mg·kg⁻¹, accompanied by a 65–85% reduction in available As. Meanwhile, soil pH, soil organic matter, and cation exchange capacity exhibited pronounced non-linear variations, with an overall tendency to recover toward pre-remediation conditions. These findings underscore the importance of long-term monitoring for evaluating remediation effectiveness and periodic assessments (e.g., semiannual monitoring of soil As and nutrient status) to support adaptive environmental management and optimization of remediation strategies. Full article

The cocontamination of arsenic (As) and cadmium (Cd) in agricultural soils poses severe risks to ecosystem stability and food safety because of their high toxicity, mobility, and bioaccumulation potential. However, single amendments often exhibit selective immobilization, which limits their effectiveness for As–Cd-cocontaminated soils. In this study, a sepiolite-supported nanoscale zero-valent iron composite (S-nZVI) was synthesized via liquid-phase reduction, and its remediation performance and mechanisms under different moisture conditions were evaluated. The characterization results confirmed that the nZVI nanoparticles were uniformly dispersed and anchored onto the sepiolite matrix, thus mitigating aggregation and oxidative passivation while increasing surface reactivity. Soil incubation experiments demonstrated that S-nZVI reduced the bioavailability of As and Cd and promoted their transformation from labile to stable fractions under both 50% and 120% water holding capacity (WHC). Under flooded conditions (120% WHC), 0.5% S-nZVI reduced the bioavailable Cd and As concentrations by 52.3–58.7% and 67.4%, respectively, after 120 days. Mechanistically, immobilization was governed by a synergistic “adsorption–reduction–coprecipitation” pathway coupled with pH–Eh regulation. Rice pot experiments further validated the effectiveness of S-nZVI, with the grain As and Cd concentrations reduced by 73.3% and 52.3%, respectively, without impairing plant growth. Overall, S-nZVI provides an efficient strategy for simultaneous immobilization of As and Cd in As–Cd-cocontaminated soils and supports the safe use of polluted agricultural lands. Full article

Arsenic (As) contamination of soils is a critical environmental and geochemical concern, with its mobility and bioavailability largely controlled by molecular-scale interactions with soil minerals. This study investigates the adsorption behavior of arsenate [As(V)] and arsenious acid [As(III)] on major clay minerals to elucidate fundamental controls on As retention in soil and sediment systems. Molecular modeling approaches were employed to investigate these interactions. Density functional theory (DFT) calculations were performed on cluster models of illite, chlorite, montmorillonite, and kaolinite to evaluate adsorption configurations and binding energies of arsenate and arsenious acid. In addition, semiempirical (PM6) and classical force-field (UFF) methods were used to examine the influence of vermicompost-derived organic matter on arsenate-mineral interactions. Multiple adsorption configurations, including atop atom, bridge, three-fold filled, and three-fold hollow sites, were evaluated, and binding energies were calculated with correction for basis set superposition error. The results indicate that three-fold hollow sites are the most favorable, with As(V) binding energies of 60–65 kcal mol⁻¹ on illite, chlorite, and montmorillonite, reaching 75 kcal mol⁻¹ on kaolinite at a surface distance of 2.7 Å. In contrast, As(III) shows weaker and energetically flatter adsorption, with binding energies of 28–54 kcal mol⁻¹ and larger equilibrium distances of 3.2–4.0 Å. Modeling of vermicompost addition suggests a substantial reduction in arsenate binding on most clay minerals, except illite, indicating competitive or disruptive interactions at mineral surfaces. These findings provide quantitative, atomistic insight into mineral- and amendment-specific controls on As stabilization and mobility in soil and sediment systems. Full article

Arsenic (As) contamination in aquatic products is a significant public health concern. This study presents a holistic investigation into the speciation, processing stability, bioaccessibility, and health risks of arsenic in crayfish from the Yangtze River basin. The analysis of 60 samples revealed total arsenic (tAs) concentrations ranging from 53.6 to 419.9 μg/kg, with a mean of 109.3 μg/kg. Arsenic occurred predominantly as low-toxicity organic species, with arsenobetaine accounting for 41.3% of tAs on average, while inorganic arsenic (iAs) constituted only 11.6% (mean 12.5 μg/kg). Evaluation of common cooking methods demonstrated that arsenic speciation remained largely stable, with no increase in toxic iAs forms. Notably, boiling in saline water led to significant leaching, reducing iAs content by 28.2%. In vitro gastrointestinal digestion revealed a markedly high bioaccessibility of iAs (81.0–99.3% in the intestinal phase), far exceeding that of tAs (50.4–74.6%). Health risk assessment based on the latest U.S. EPA parameters indicated negligible non-carcinogenic risk across all exposure scenarios. However, the estimated carcinogenic risk for high-intake consumers of high-iAs samples exceeded the acceptable threshold of concern. These findings are expected to provide essential data for understanding the health risks posed by arsenic in crayfish and to support accurate food safety evaluations. Full article