Search Results (615)

This study investigated the biogeochemical processes governing heavy metal sequestration in Laguna Honda, a hypersaline Mediterranean wetland affected by intensive olive cultivation located in the Guadalquivir Basin River (S Spain). A network of sediment samples was analyzed from the wetland using X-ray fluorescence, ICP-MS, and high-resolution electron microscopy (FESEM/HRTEM). Geochemical data were treated with statistical factor analysis. Sediments show significant enrichment of Cu, Hg, and Au due to anthropogenic agrochemical treatments. Mineralogical characterization revealed authigenic pyrite framboids and metallic sulfide nanoparticles (CuS and HgS) within organic-rich sediments, where sequestration is primarily probably driven by the metabolic activity of sulfate-reducing microorganisms (SRMs) under reducing conditions. Additionally, Au enrichment is attributed to mechanical transport and coagulation of pesticide-derived nanoparticles, exhibiting a distinct geochemical correlation with rare earth elements (REEs). We concluded that hypersaline wetlands act as critical environmental sinks, where microbial activity, high organic matter content, and detrital transportation interact to facilitate the immobilization and stabilization of toxic trace elements through the precipitation of low-solubility sulfide phases (Cu and Hg) and the mechanical accumulation of nanoparticles (Au). Full article

Upon entering aquatic ecosystems, coal fly ash (CFA) particles and their leachates distribute across all environmental compartments, from surface water to benthic sediments, rendering them accessible to aquatic organisms spanning multiple trophic levels. Although CFA is widely classified as non-hazardous waste, a growing body of toxicological evidence demonstrates its capacity to induce significant adverse biological effects. This discrepancy between laboratory-demonstrated toxicity and its current non-hazardous regulatory status highlights a critical knowledge gap in risk assessment frameworks and testing philosophies. Herein, we provide a comprehensive review of CFA characterization techniques, leaching methodologies and their environmental relevance, and the aquatic ecotoxicity of both particulates and leachates to primary, secondary, and tertiary consumers. Based on the findings from the review, we propose four paradigm shifts to more accurately characterize CFA ecotoxicological risks: from standardized leaching protocols to application-specific and maximum leachability tests, from single-species assays to multi-trophic-level bioassays, from single-metal analysis to comprehensive, whole-matrix testing that integrates particulate and dissolved fractions, and from standardizing the reporting of CFA provenance, coal types, and combustion conditions to meaningful meta-analyses and cross-study comparisons. It is believed that these suggestions will substantially advance the realistic ecotoxicological assessment of CFA and bridge the gap between laboratory toxicity data and regulatory classification. Full article

Trace elements are essential for plant growth, yet their dose-dependent effects on root system development still remain poorly characterized across diverse plant functional types. We investigated the effects of manganese (Mn), cobalt (Co), and molybdenum (Mo) across 10 concentration gradients (0–500% of standard Hoagland nutrient solution) on root length, tip number, biomass, and activity in four species: Triticum aestivum L., Zea mays L., Ipomoea aquatica Forssk. in Forssk. & Niebuhr, and Canna glauca L. After 30 days of hydroponic culture, our results showed that Mn and Mo elicited significant, concentration-dependent responses across all species. Root traits improved progressively with increasing concentrations from deficiency to optimal levels, but declined when concentrations exceeded the optimal range. The optimal ranges were 25–100% for Mn and 50–150% for Mo, while concentrations above 150% generally proved toxic. By contrast, Co effects were comparatively limited, with significant inhibition only at concentrations exceeding 100%. Species-specific responses were also evident: T. aestivum and Z. mays were more sensitive to Mn and Mo excess, whereas I. aquatica and C. glauca displayed broader tolerance, with C. glauca showing notably high Mo utilization efficiency. Notably, all four root traits exhibited strong positive correlations (r > 0.90, p < 0.001), indicating coordinated morphological and physiological plasticity. Collectively, our findings provide quantitative evidence for species-specific trace element management and contribute to a more nuanced understanding of trace element regulation of root system architecture. Full article

Osteoarthritis (OA) and other rheumatic diseases are among the leading causes of chronic pain, disability, and reduced quality of life worldwide. Increasing evidence indicates that disturbances in metal homeostasis contribute to the pathogenesis of these disorders through their effects on oxidative stress, immune regulation, cartilage metabolism, bone remodeling, and extracellular matrix degradation. This review summarizes current knowledge regarding the role of essential metals and trace elements, including zinc, iron, copper, magnesium, selenium, and manganese, as well as toxic metals such as cadmium, lead, mercury, and arsenic, with primary emphasis on their involvement in the development and progression of osteoarthritis. Other rheumatic diseases are discussed briefly to provide a comparative perspective. Particular attention is given to the molecular mechanisms underlying metal-mediated pathology, including oxidative stress, ferroptosis, mitochondrial dysfunction, activation of intracellular signaling pathways, and inflammasome activation. The diagnostic and therapeutic potential of metal-related biomarkers, metalomics, and targeted interventions aimed at restoring metal homeostasis are also discussed. Furthermore, current limitations of available studies and emerging research directions, including single-cell technologies, spatial transcriptomics, multi-omics approaches, and personalized medicine, are highlighted. A better understanding of metal homeostasis may improve the identification of novel biomarkers and therapeutic targets, ultimately contributing to more precise diagnosis and individualized treatment strategies for osteoarthritis and other rheumatic diseases. Full article

Potentially toxic elements (PTEs) are one of the most concerning pollutant types in the surface environment. In this study, a total of 115 farmland soils from the 0–20 cm layer were collected from the Ibinur Lake Basin (ILB) in northwest China to investigate the concentration characteristics, pollution status, potential ecological risks, and possible sources of seven PTEs (As, Cd, Cu, Ni, Pb, Hg, and Zn). The pollution load index (PLI) method was applied to quantify soil pollution status, while the potential ecological risk index (RI) was adopted to evaluate PTE-induced ecological risks. Multivariate statistical approaches were further implemented to trace the potential sources of these PTEs. The obtained results revealed that the average concentrations of As, Cd, Ni, Pb, and Zn present in farmland soil surpass the corresponding background values by factors of 2.41, 1.99, 1.15, 1.18, and 5.60, respectively. Single-factor pollution assessment indicated heavy Zn pollution, moderate As pollution, low-level Cd, Pb, and Ni pollution, and slight Cu pollution across farmland soils in the ILB, whereas no Hg pollution was detected. PTEs in farmland soil show a low pollution level, with an average PLI value of 1.31. Obvious spatial heterogeneity was observed in the distribution of all seven PTEs. The comprehensive potential ecological risk of PTEs remained low, with an average RI of 23.87; among all target PTEs, As and Cd contributed the largest share of ecological risks. Source apportionment demonstrated that Cd, Cu, Ni, Pb, and Zn were potentially derived from combined natural and anthropogenic inputs, Hg was likely associated with lithogenic natural sources, and As was potentially derived from agricultural anthropogenic activities. Collectively, As and Cd were identified as the priority pollutants posing pollution and ecological risks in this basin. This study improves the systematic understanding of PTE pollution risks in arid agricultural soils and the results suggest that regular long-term monitoring should be implemented for local soils. Full article

Juniperus species form critical, long-lived high-mountain forest ecosystems in Central Asia, serving essential phytocoenotic and ecological functions in environmentally challenging habitats. However, the relationships between the elemental composition of these evergreen conifers and their underlying soils remain poorly understood. This study evaluated and compared the distribution of major elements (Fe, Ca, P, Mg, Al, Na, K, S), trace elements (Cu, Pb, Zn, Ni, Co, Mn, As, Cd, Cr, Mo, U, Th, Sr, Sb, Bi, V, La, Ba, Ti, B, W, Sc, Zr, Tl, Ta, Nb, Se, Te, Ga, Cs, Ge, Hf, Rb, Sn and others), and environmental pollution indices (Igeo, EF, CF, BAF) in plant tissues (leaves and cones) and canopy soils of three key juniper species (Juniperus seravschanica, J. turkestanica, and J. semiglobosa) in the Fann Mountains, Tajikistan. Soil and plant samples were collected across natural habitats and analyzed for total chemical composition using ICP-OES. The soils showed a near-neutral reaction (pH 7.02–7.42 in H₂O and 6.41–7.15 in KCl), with considerable variability in Corg. content (5.04%–21.82%) and Nt content (0.337%–1.149%) in the humus (A) horizons. Geochemical indices (Igeo up to 2.42, EF up to 35.30) indicated noticeable soil enrichment and localized contamination by arsenic (As) and cadmium (Cd), likely driven by a combination of regional industrial and mining activities alongside natural geogenic enrichment. Across all sites, elemental concentrations followed a consistent sequence: soil > leaves ≈ cones. Heavy metals in plant tissues remained well below toxic thresholds. High organ-specific partitioning was observed: K predominated in cones (K > Ca > P), whereas Ca and Fe accumulated predominantly in leaves (Ca > K). Low bioaccumulation factor values (BAF < 1) indicate limited element accumulation relative to total soil concentrations for all three species, which may be influenced by both reduced bioavailability in neutral-to-alkaline soils and potential physiological regulation. As the first data reported from this region, these findings establish an essential baseline for long-term ecological monitoring, soil–plant chemistry, conservation, and environmental risk assessment in the Fann Mountains’ juniper ecosystems. Full article

Under intensive urbanization, botanical gardens soils can serve as reference plots for urban areas, reflecting both natural (pedogenic) and anthropogenic factors of soil formation. In this context, historical and archeological information on the Botanical garden of Saint Petersburg State University (BG SPbU) is presented. For the first time, morphological, physicochemical, and ecotoxicological characteristics of the BG SPbU soils are assessed using full-profile soil pits. The ecological features of the BG SPbU are noted, and the specific structure of the upper soil layer (up to 2 m) is examined. The physicochemical properties of the BG SPbU soils are consistent with the optimal levels for green spaces of the highest (I) category. In the 0–90 cm layer of the studied soil pits, elevated concentrations (relative to Russian regulatory standards) of toxic trace elements (lead, zinc, arsenic) are found. No signs of vegetation stress were detected during the survey. At the same time, the measured concentrations of Pb, Zn, and As exceed the Russian MPC (maximum permissible concentrations) and APC (approximate permissible concentrations) for heavy metals. These exceedances provide important information for further monitoring and decision-making regarding urban pollution regulation, and contribute to the discussion on revising the MPC and APC values in line with international standards. The results can be used to optimize management practices for green spaces of the BG SPbU and can also be incorporated into the long-term urban environmental monitoring program initiated in Saint Petersburg in 1991. Full article

Human biomonitoring in environmentally complex regions requires not only matrices that are easy to collect but also careful consideration of external contamination, non-detects, and analytical uncertainty. Inductively coupled plasma mass spectrometry (ICP–MS) was used to measure the concentrations of 24 elements in occipital scalp-hair samples from 134 adults living in Campania, southern Italy (67 women and 67 men; age range: 20–72 yr). Continuous models were restricted to elements detected in at least 70% of adults and were fitted using HC3 heteroskedasticity-consistent standard errors, with Benjamini–Hochberg correction for the false discovery rate (FDR). Ca, Zn, Mg, K and Cu were the most abundant elements in the hair profile. The most consistent adjusted association was lower concentrations of Ca, Mg, Cu, Cr and Zn in men. Pb showed a strongly right-skewed distribution, whereas Cd was detected in only 22.4% of adults; this low detection frequency did not support a population-level elevation claim. Spatial summaries and clustering were retained for exploratory purposes: Kruskal–Wallis tests indicated a zone-level difference only for Zn, whereas patterns in Pb, Cr, As, Cd, and V were interpreted as priorities for confirmatory sampling rather than as evidence of territorial risk. Sensitivity analyses based on the limit of detection (LOD) supported retaining As and Cd as descriptive outcomes; V associations were not promoted to primary findings because the V detection frequency was below the pre-specified threshold. These findings support the use of hair biomonitoring as a non-invasive screening approach in mixed geogenic–anthropogenic settings, provided that sex, sample mass, non-detects, outliers, and external contamination are considered explicitly and that confirmatory matrices are used where appropriate. Full article

This study investigated the elemental composition along the soil–plant continuum of Sicilian citrus fruits grown in volcanic (Stromboli and Etna) and non-volcanic (Marsala) areas. Following microwave-assisted acid digestion, macro- and trace elements were quantified via ICP-MS in soils, whole fruits, peel, pulp, and juice. Citrus fruits from volcanic areas generally showed higher concentrations of K, P, Fe, and Al than those from Marsala. Potentially toxic elements in edible fractions were generally low, with Pb and Cd below the applicable regulatory limits. Elemental partitioning showed higher measured concentrations of several potentially toxic elements in the peel, with lower concentrations in pulp and juice. Principal Component Analysis (PCA) revealed separation of samples according to geographical origin, while Linear Discriminant Analysis (LDA) achieved complete classification within the investigated dataset, with K, Al, Mg, and Ni. These findings indicate that elemental fingerprinting may support geographical characterization, together with nutritional and toxicological assessment. Full article

The liver plays a central role in fatty acid (FA) metabolism, triacylglycerol synthesis, and energy homeostasis. The study aims to evaluate how a four-week dietary intervention with fish-based (EF), milk-based (EM), and standard diets (ES) affects relationships between mineral levels, FA profiles and indices, and oxidative stress parameters in female Wistar rats. Liver tissue samples were collected and analyzed for these variables. Post hoc analysis revealed significant differences in trace elements between the EM and EF and the EM and ES groups, and in toxic trace elements only between the EM and EF groups. Individual mineral differences were observed for calcium (Ca), iron (Fe), copper (Cu), zinc (Zn), arsenic (As), mercury (Hg), and lead (Pb), all showing large effect sizes (ηp² = 0.32–0.63). The strongest mineral–FA correlations occurred mainly in the ES group (15/25) and, to a lesser extent, in EF (9/25), involving 14 minerals, while only one mineral was significant in EM. Individual mineral correlations were most frequent in ES (13/25), followed by EF (8/25) and EM (4/25). Zn was the strongest predictor of malondialdehyde (MDA) in EF (90.6%), and Cu was the main determinant in ES (72.9%). We concluded that EM showed minimal interactions, limited to Fe and oleic acid, whereas EF and ES displayed multiple strong mineral–FA correlations, with ES exhibiting the most extensive and complex interaction network. Full article

Historical mining districts are long-term sources of environmental contamination, especially where agriculture and grazing occur near mining areas. This study evaluates mercury (Hg) and other potentially toxic elements (PTEs) in soils from Solana de Peñarrubia, within the Almadén mining district (Spain). Thirty-four soil samples collected using a regular staggered grid were analyzed for total Hg and major oxides and selected trace elements. Spatial patterns were evaluated using Kriging interpolation, hierarchical clustering, PCA, and the geoaccumulation index, after standardizing variables to minimize differences in magnitude among them. Thermal desorption and microscopy were performed on three selected high-Hg samples, with thermal assignments interpreted as operational rather than definitive mineralogical identifications. Hg concentrations ranged from 10 to 994 mg kg⁻¹, with the highest values in the northern sector. The PCA separated cropland soils, associated mainly with lithological variables, from soils with anthropogenic inputs related to Hg, Pb, SO₃, and SiO₂. The geoaccumulation index indicated Hg enrichment, reaching the extremely polluted category at the maximum concentration. Thermal desorption profiles were dominated by fractions within the reference range of α-HgS, accounting for 78.27–87.44% of the estimated relative abundance, while microscopic examination revealed particles consistent with cinnabar in high-Hg samples. The Hg anomaly showed no straightforward relationship with the mapped local lithology and may partly reflect, as a working hypothesis, the possible redistribution of Hg-bearing mineralized materials associated with historical mining or metallurgical activities. Full article

Municipal solid waste landfill leachate represents one of the most environmentally challenging liquid effluents in modern waste management; however, its high nitrogen and phosphorus content renders it a potentially valuable nutrient source for microalgal phycoremediation. Here, Chlorella sp. and Scenedesmus sp. were cultivated for 15 days in CHU-10 standard medium and 50% (v/v) municipal landfill leachate from Nauta, Peru, and characterized across 33 biochemical variables, 14 physicochemical parameters, and 32 metal ions and trace elements. A sequential competitive multivariate pipeline comprising principal component analysis (PCA), hierarchical cluster analysis (HCA), permutational multivariate analysis of variance (PERMANOVA), and linear discriminant analysis (LDA) was applied to both the biochemical and bioremediation datasets. Leachate supplementation increased peak biomass density by 26.6–28.3% and elevated total protein by 56.9% in Chlorella sp. and 73.4% in Scenedesmus sp., while reducing total lipids by 37–46% and suppressing polyunsaturated fatty acid production. Both species achieved net biological removal efficiencies (NBRE) exceeding 86% for ammonium and ammonia; toxic elements, including Cd (~96%), Al (~92%), As (~90%), and Pb (~90%), were removed at higher NBRE than macro- and micronutrient categories. LDA achieved 100% leave-one-out cross-validation accuracy for species classification from both physicochemical and 32-element NBRE profiles. These findings indicate two complementary valorization directions, contingent on further biomass safety verification: leachate-grown Scenedesmus sp. shows a favorable combination of protein enrichment and nutrient removal for single-cell protein production integrated with bioremediation, while Chlorella sp. in standard medium shows a more favorable fatty acid profile for nutraceutical applications. Because leachate-grown biomass also accumulates inorganic and trace-element constituents from the medium, its suitability for protein or nutraceutical use requires direct heavy-metal characterization of the harvested biomass, independent of the demonstrated removal efficiency from the liquid phase. Full article

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

Selenium (Se) is an essential trace element for humans and animals, with nutritional functions and abiotic stress regulation capacity, and has been confirmed to alleviate heavy metal toxicity and inhibit its accumulation in crops. Soil lead contamination has become a prominent environmental safety problem in agricultural production, particularly in South China, and lead over-standard in edible crops poses irreversible threats to the human nervous system and blood circulation through food chain transmission. As an efficient exogenous antagonist, Se can comprehensively regulate the absorption, translocation, and compartmentalization of lead in soil–plant systems. This review systematically summarizes the interactive effects of soil physicochemical properties, crop genotypes, and Se speciation on plant lead uptake, and focuses on phytochelatin synthase (PCS), the core rate-limiting enzyme for intracellular heavy metal chelation, to elucidate the molecular cascade of Se-mediated PCS-dependent lead detoxification. We further outline multi-pathway agronomic Se applications for lead reduction; analyze key limiting factors, including Se concentration, application method, and rhizosphere microbial community; and discuss contradictory results and unresolved questions in existing studies. Current evidence confirms that appropriate Se treatment increases glutathione (GSH) content via antioxidant system regulation, upregulates PCS gene transcription and activity, promotes phytochelatins (PCs) polymerization, and forms stable PC-Pb complexes sequestered in vacuoles to reduce cytoplasmic lead mobility. Additionally, Se reshapes rhizosphere microbial community composition to lower soil Pb²⁺ bioavailability and enhances lignin and pectin biosynthesis in root cell walls to physically block root Pb²⁺ influx. Nevertheless, critical knowledge gaps remain unaddressed: (1) upstream signal transduction cascades triggering Se-induced differential PCS expression; (2) precise Pb²⁺ binding sites and affinity of PC oligomers; (3) valence-dependent disparities in selenate, selenite, and nano-Se (SeNPs) modulating PCS activity; and (4) standardized field Se fertilization protocols tailored to staple and tropical tuber crops such as cassava. This review provides systematic theoretical reference and technical foundations for dissecting Se-Pb antagonistic molecular networks, developing Se-enriched low Pb²⁺ functional fertilizers, and mitigating Pb²⁺ contamination risk in agricultural commodities. Full article

Background: Accurate assessment of microelement and toxic element content in animal diets is essential for diet formulation, quality control, and exposure assessment; however, predictive additive models may not fully account for variability arising from raw materials and processing factors. Methods: This study evaluated the composition of microelements and toxic elements in the four diets enriched with 4% beetroot cultivars Boldor and Wodan, either without (level 1) or with (level 3) foliar application of the selenium–based plant growth stimulator. Predicted values (calculated using an additive model P = 0.96 × C _{basal diet} + 0.04 × C _{beetroot component}) were compared with experimentally measured concentrations (M). Four dietary variants Boldor 1, Boldor 3, Wodan 1 and Wodan 3 were analyzed. Elemental concentrations of Fe, Zn, Cu, Cr, Ni, Se, Pb, As, Cd, and Sb were determined using ICP-MS. Results: Substantial discrepancies between predicted (P) and measured (M) values were observed. The largest deviations occurred for Cr, Fe, and Sb. Cr and Sb were generally underestimated by the model, whereas Fe was consistently overestimated. Selenium (Se) showed moderate variability, while Cu, Zn, and Ni exhibited close agreement between predicted and measured values. The largest measured cultivar-related differences were observed for As (2.87-fold), Cd (2.78-fold), Pb (2.47-fold), Cr (2.37-fold), Fe (1.73-fold), Sb (1.57-fold), Cu (1.13-fold), and Zn (1.05-fold), all of which occurred at higher concentrations in Wodan than in Boldor. No statistically significant effect of the selenium–based plant growth stimulator was observed. Conclusions: Overall, the results demonstrate that additive models have limited accuracy in predicting trace element composition in complex diets, particularly for elements potentially affected by raw-material variability, sampling heterogeneity, and analytical uncertainty. The contribution of the dietary 4% beetroot component played a key role in shaping element distribution, particularly for elements with high component-to-basal diet ratios. These findings highlight the importance of proper mixing, prevention of segregation in powdered diets, and strict control of raw material quality. Full article