Search Results (1,269)

Floods and wildfires are two extreme environmental events with significant yet different impacts on soil health and on two particularly important soil pollutants, heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs), which are directly associated with ishytoxic properties and their ability to enter the food chain. The present study includes a methodological approach that was based on a literature review of published studies conducted worldwide regarding these two phenomena. The main forms of both pollutants, their possible sources and inevitable deposition onto the soil surface, along with their behavior–transport–mobility, and their residence time in soil were investigated. Furthermore, the changes that both HMs and PAHs induce in the physicochemical properties of post-flood and post-fire soils (in soil pH, Cation Exchange Capacity (CEC), organic matter content, porosity, mineralogical alterations, etc.), are investigated after a literature review of various case studies. Wildfires, in contrast to floods, can more easily remove large quantities of heavy metals into the soil ecosystem, most likely due to the intense erosion they cause. At the same time, floods appear to significantly burden soils with PAHs. In wildfires, the largest mean increases were observed for Mn (386%), Zn (300%), and Cu (202%). In floods, Pb showed the highest mean increase (534%), with Cd also rising substantially (236%). Regarding total PAHs, mean post-event concentrations reached 482.3 μg/kg after wildfires, compared to 4384 μg/kg after floods. Changes in the structure and chemical composition of flooded and burned soils may also affect the mobility and bioavailability of the pollutants under study. Overall, these two phenomena significantly alter soil quality, affecting both ecological processes and potential health impacts. Full article

Early oxidative stress caused by titanium implants can impair osseointegration. Manganese dioxide (MnO₂) nanozyme coatings have the potential to scavenge H₂O₂ and simultaneously generate O₂ to alleviate hypoxia, but their activity is mostly static, and the ion release is detrimental. A nano-MnO₂/Ti/P(VDF-TrFE) sandwich-structured composite was fabricated, and ferroelectric polarization was applied to preset a tunable surface potential. Kelvin probe force microscopy (KPFM) verified a presettable potential within ±500 mV. Steady-state kinetics confirmed an enhancement in overall catalytic efficiency (higher V_max and lower K_m). This translated to a faster initial decomposition rate at a low, physiologically relevant H₂O₂ concentration (300 μM). Correspondingly, under these oxidative stress conditions, cell survival in the polarized group was higher than that in the unpolarized group, indicating that the enhanced initial rate can have a positive effect in such conditions. Overall, this study demonstrates a proof-of-concept strategy to tune MnO₂ nanozyme catalysis using a polarization-preset surface potential, targeting implantation-relevant ROS-rich conditions. Full article

Introduction: Human breast milk (HBM) is a critical source of nourishment for newborns, containing bioactive compounds that influence infant growth and metabolic programming. Among these compounds, leptin—a hormone primarily produced by adipocytes but also synthesized in the mammary gland—has gathered attention for its potential role in regulating energy balance and body weight. This study investigates the influence of maternal factors on HBM leptin concentrations and explores their associations with neonatal growth parameters. Material and Methods: 262 HBM samples were collected from healthy lactating mothers through Spanish Biobanks during the first six months postpartum. Data on maternal characteristics (body mass index (BMI), age, physical activity, parity, and delivery type) and neonatal measurements (weight, length, and head circumference) were collected. Leptin concentrations in skimmed HBM were measured using the ELISA technique (R&D Systems™, Minneapolis, MN, USA). Statistical analyses were conducted using R version 4.3.1 and MATLAB R2023a, with significance set at p < 0.05. Results: Leptin levels were highest in and declined over time, reaching a stable level after the first month of lactation. Preterm deliveries exhibited significantly higher leptin concentrations than term deliveries (0.42 vs. 0.07 ng/mL). Higher leptin levels were also observed in younger and primiparous mothers. Maternal BMI was positively associated with leptin concentration, with mothers who had elevated BMI showing higher levels than those with optimal BMI (0.36 vs. 0.05 ng/mL). Maternal physical activity was not associated with leptin concentrations in univariate analyses; although greater self-reported physical activity appeared associated with lower leptin concentrations in regression models, this finding should be interpreted cautiously and should not be considered evidence of an independent or consistent effect. Neonatal growth parameters (weight, length, and head circumference) were negatively correlated with HBM leptin concentrations. Conclusions: Our findings indicate that leptin levels in breast milk reflect both maternal metabolic status and neonatal characteristics and may represent a compensatory mechanism in preterm infants. HBM leptin levels are modulated by maternal BMI, age, parity, and delivery type, and are associated with neonatal growth parameters. Full article

Citrus trees are mainly cultivated in acidic soils. Excessive manganese (Mn) is the second most limiting factor for crop productivity in acidic soils after aluminum toxicity. The roles of reactive oxygen species (ROS) and methylglyoxal (MG) detoxification systems in augmented pH-mediated amelioration of excessive Mn are poorly understood. ‘Sour pummelo’ (Citrus grandis (L.) Osbeck) seedlings were exposed to nutrient solution at a Mn concentration of 500 (Mn500) or 2 (Mn2) μM and a pH of 3 (P3) or 5 (P5). The increase in pH attenuated Mn500-induced increases in ROS production and MG and malondialdehyde accumulation in roots and leaves. Additionally, the increase in pH enhanced the coordinated detoxification capability of both ROS and methylglyoxal scavenging systems in these tissues under Mn500. These findings corroborated the hypothesis that augmenting pH enhances the capability of these tissues to detoxify ROS and methylglyoxal under Mn excess. Therefore, this study provided new evidence on the roles of ROS and MG detoxification systems in the augmented pH-mediated amelioration of oxidative damage in ‘Sour pummelo’ leaves and roots caused by Mn excess, as well as a basis for correcting Mn toxicity by augmenting soil pH. Full article

Red mud (RM) and electrolytic manganese residue (EMR) possess inherently complementary acid–base characteristics, and their synergistic utilization offers a promising approach to simultaneously enhance mechanical performance and mitigate environmental risks. However, the environmental behavior of RM-EMR composites, particularly in terms of pH buffering, ammonium nitrogen (NH₄⁺-N) control, and heavy metal mobility, remains inadequately understood. In this study, a composite cementitious paste was developed using RM and EMR, and the effects of the RM-to-EMR ratio (1: 3, 2: 3, 1: 1, and 3: 2), alkali activator dosage (30%, 40%, 50% and 60% by weight), and curing time (3 day, 7 day, 14 day, and 28 day) under standard curing conditions on unconfined compressive strength (UCS) were systematically evaluated. Leaching tests were conducted to assess pH evolution, NH₄⁺-N release, and heavy metal migration. The results showed that the optimal 28-day UCS of 35 MPa was achieved with an RM-to-EMR mass ratio of 2:3 and an activator dosage of 60%. EMR contributed to NH₄⁺-N leaching concentrations as high as 302 mg/L; however, under alkaline conditions (pH > 11), over 50% of the block samples met regulatory limits due to the transformation of NH₄⁺ into gaseous NH₃. Furthermore, Mn and Cd were effectively immobilized. In contrast, Al and Se exhibited elevated leaching, with Al showing particularly high concentrations under water leaching conditions. These results underscore the importance of raw material pretreatment and system optimization. Overall, this study provides new insights into the environmental behavior and safe resource utilization of RM and EMR in cementitious systems. Full article

Tuber crops cultivated in basalt-derived soils are influenced by naturally high geochemical backgrounds, which may elevate heavy metal(loid) levels and associated health risks. To clarify the geochemical controls governing metal accumulation, this study analyzed rock, soil, and tuber (sweet potato and yam) samples from the Qiongbei volcanic area of Hainan Island, China. Concentrations of eight heavy metal(loid)s (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) and 22 nutrient-related indicators (N, P, K, SOC, S, Se, Fe, Mn, and their available fractions) were determined. Soil contamination and potential human health risks were evaluated using the pollution index and the health risk model. The results showed that 11.1–55.6% of soil samples exceeded pollution thresholds for Cr, Cu, Ni, and Zn, reflecting typical basaltic high-background characteristics. In contrast, heavy metal(loid) concentrations in tuber crops were relatively low and jointly regulated by parent material composition and soil nutrient status. Non-carcinogenic risks (HI) were below 1, indicating acceptable exposure levels, while carcinogenic risks were mainly associated with Cd, Cr, and Pb, with total carcinogenic risk (TCR) exceeding 1 × 10⁻⁴, suggesting potential health concerns. Strong correlations between soil nutrients (N, P, K, SOC, S, Se, Mn, and Fe) and plant uptake of As, Cd, Cu, and Cr indicate that nutrient availability plays a crucial role in controlling heavy metal(loid) bioavailability. The volcanic soils exhibited a “high total content–low bioavailability” pattern. Enhancing soil Se, SOC, available N, and slowly available K (SAK) can effectively reduce Cd and other high-risk metal accumulation in tuber crops. These findings elucidate the key geochemical processes influencing heavy metal transfer in volcanic agroecosystems and provide a scientific basis for safe agricultural utilization and health risk prevention in high-background regions. Full article

In flooded soils, the concentrations of exchangeable Mn²⁺ and, especially, Fe²⁺ can be high and must be considered when determining the cation exchange capacity (CEC) of the soil under flooded conditions. However, these reduced forms of Mn and Fe are oxidized and precipitated during the extraction process used in traditional CEC methods. This procedure underestimates the exchangeable portion of these cations and, consequently, the CEC value of the flooded soil. We introduce a pH-gradient-based model to predict ECEC and exchangeable Fe²⁺ in flooded soils, circumventing oxidation artifacts inherent in conventional methods. The objective of this study is to propose an alternative to estimate the exchangeable Fe²⁺ and the effective CEC (ECEC) of flooded soils. To achieve this goal, 21 surface samples (0–20 cm) of soil from rice fields were collected and distributed in the cultivation regions of southern Brazil. The soils were flooded for 50 days. The soil solution was collected on the first day and after 50 days of flooding and pH, Na, K, Ca, Mg, Fe and Mn were determined. In these samples, exchangeable cations (K, Na, Ca, Mg, Mn, Al and H + Al) were determined to calculate ECEC and CEC at pH 7 of unflooded soil and after 50 days of flooding. There was a wide range of variation in the exchangeable cation contents among the soil samples. The K contents ranged from 0.12 to 0.54 cmol_c kg⁻¹, the Na contents from 0.00 to 1.18 cmol_c kg⁻¹, the Ca contents from 0.48 to 37.31 cmol_c kg⁻¹, the Mg contents from 0.10 to 15.53 cmol_c kg⁻¹, the Mn contents from 0.01 to 0.36 cmol_c kg⁻¹, the Al contents from 0.10 to 1.74 cmol_c kg⁻¹ and the H + Al contents from 2.01 to 8.42 cmol_c kg⁻¹. The results were used to develop models to predict ECEC and exchangeable Fe content after 50 days of flooding. Estimating the ECEC after flooding using the pH gradient before and after flooding yielded values closer to CEC pH 7.0, correcting for the possible underestimation of the ECEC during flooding. The amount of exchangeable Fe estimated was higher than the exchangeable Fe determined, correcting the possible underestimation of these quantities determined during flooding. It is concluded that the estimations of ECEC after flooding through the equation ${ECEC}_{after}=ECEC+\left({pH}_{sol.after}-{pH}_{sol.before}\right)\times {\displaystyle \frac{({CEC}_{pH7}-ECEC)}{(7-{pH}_{sol.before})}}$, where pH_sol.before is pre-flooding soil pH, pH_sol.after is after flooding pH, ECEC_after is effective CEC after flooding and the exchangeable Fe²⁺ after flooding through the equation ${Fe}_{exc.after.estimated}={ECEC}_{after}-\left(Ca+Mg+K+Na+Mn\right)$ where Fe_{exc.after.estimated} is estimated exchangeable Fe²⁺ after flooding corrected the problem of underestimating the values of these variables by analytical methods, demonstrating its viability for use in flood-prone soils. Full article

Heavy metal enrichment in agricultural soils can affect crop safety, ecosystem functioning, and long-term land productivity, yet farm-scale screening is often constrained by limited routine monitoring data. This study develops a GIS-based framework that combines field-scale spatial analysis with explainable machine learning to characterize and predict heavy metal enrichment on an intensively managed cereal farm in eastern Kazakhstan. Topsoil samples (0 to 20 cm) were collected from 34 fields across eight campaigns between 2020 and 2023, yielding 241 composite field–campaign observations for eight metals (Pb, Cu, Zn, Ni, Cr, Mo, Fe, and Mn) and routine soil properties (humus, pH in H₂O, and pH in KCl). Concentrations were generally low but spatially heterogeneous, with wide observed ranges for several elements (for example, Pb 0.06 to 2.20 mg kg⁻¹, Zn 0.38 to 7.00 mg kg⁻¹, and Mn 0.20 to 38.0 mg kg⁻¹). We synthesized multi-metal structure using an HMI defined as the unweighted mean of z-standardized metal concentrations, which supported field-level screening of persistent enrichment and emerging hot spots. We then trained Extreme Gradient Boosting models using only humus and pH predictors and evaluated performance with field-based spatial block cross-validation. Predictive skill was modest but nonzero for several targets, including HMI (mean R² = 0.20), indicating partial spatial transferability under conservative validation. SHAP analysis identified humus content and soil acidity as dominant contributors to HMI prediction. Overall, the workflow provides a transparent approach for field-scale screening of heavy metal enrichment and establishes a foundation for future integration with satellite-derived covariates for broader monitoring applications. Full article

Although excessive manganese (Mn) exposure is known to cause neuromotor function in cases of poisoning, its effect on grip strength (a neuromotor marker) in older adults at environmental levels remains unclear. To investigate this issue, we conducted an integrated investigation combining epidemiology and animal experimentation to examine the association between urinary manganese and grip strength. A cross-sectional study of 375 elderly men (60–74 years) was conducted in Guangxi, China, from 2016 to 2017. Urinary Mn concentrations were determined by ICP-MS, and their associations with grip strength were evaluated using generalized linear models and restricted cubic splines. In parallel, 32 six-week-old male C57BL/6J mice were exposed to 0, 5, 10, or 15 mg/kg MnCl₂·4H₂O via intraperitoneal injection for 6 weeks. Forelimb grip strength of the mice was measured after the final exposure, and mRNA expression of inflammatory markers and cytokines (C reactive protein (CRP), interleukin (IL)-6, and tumor necrosis factor (TNF)-α in triceps) in triceps tissue was quantified. The median urinary Mn concentration in the study population was 0.22 μg/g creatinine. After adjusting for confounders, urinary Mn was inversely associated with hand grip strength (highest vs. lowest tertile: β = −3.57 kg; 95% CI: −5.68 to −1.47; p-trend = 0.007). Similarly, in male C57BL/6J mice, grip strengths declined significantly with increasing Mn exposure (p-trend < 0.0001), accompanied by upregulation of the mRNA levels of CRP, IL-6 and TNF-α in muscle tissue. Together, our findings suggest that environmental manganese exposure is inversely associated with grip strength in elderly men. While the manganese doses used in the animal study exceeded typical human environmental exposure, the experimental results further indicate that such grip strength reduction may be linked to muscle inflammation. Full article

Chinese yam (Dioscorea polystachya) serves as both a food crop and a traditional Chinese medicine herb, yet it suffers from severe continuous cropping obstacles, typically requiring a six-year fallow period before replanting. Long-term continuous cropping changes soil properties, including the concentration of N, P, and K, as well as bacterial composition, but the overall impact of short-term continuous cropping on important soil factors such as mineral elements, enzymes, and microbial composition still remains poorly understood. To elucidate how monoculture affects soil health, we collected rhizosphere soils from D. polystachya fields under one-, two-, and three-year continuous cropping in Chenji Town, and analyzed soil properties using general chemical methods, as well as microbial composition by Illuminar high-throughput sequencing of 16S rRNA and ITS1 regions. Furthermore, the correlation between soil properties and microbial communities was examined. The results showed that soil pH, cation exchange capacity, and organic matter content increased significantly in continuous cropping soil, whereas the concentrations of soil mineral elements (N, P, K, Ca, Mg, Na, Cu, Fe, Mn, Zn, S, and Si) decreased significantly, with the concentration of available P, K, Cu, and Zn decreased by 72.8%, 64.1%, 99.3%, and 79.4%, respectively, in 3-year continuously cropped soil. Enzyme activities, including sucrase, urease, and alkaline phosphatase, also showed a decrease of more than 81%. Fungal diversity and abundance were markedly reduced with cropping duration, whereas bacterial communities showed less response. Notably, pathogenic fungi such as Dactylonectria, Neocosmospora, and Ilyonectria, along with bacteria Streptomyces, became enriched. These microbial shifts were primarily associated with soil pH, available potassium, and alkaline phosphatase. Our study demonstrates that the decline in soil fertility coupled with pathogen buildup constitutes a major cause of the continuous cropping obstacle in Chinese yams. The results provide a scientific basis for developing targeted strategies to mitigate continuous cropping obstacles in Chinese yam production. Full article

Application of CFA-treated biosolids (NVS) offers multiple benefits to agricultural soils, including fertilizer replacement, soil rehabilitation, and disinfection. It also poses a heavy metal(loid)s threat to the agro-environment. NVS (and CFA to some extent) was tested in lysimeter and field trials, using soils differing in physicochemical properties and a large selection of crops. Consistently, As, Pb, and Cd concentrations in leachate were at or below detection limit, and these and other heavy metal(loid)s (and P) were within the permitted range in plant tissue. Foliage Mo (occasionally also Se, P) concentrations often increased significantly, especially in crops (legumes, potatoes) grown on marginal soils, which also displayed significantly higher yields. CFA and NVS reduced lettuce and legumes foliage Mn (and occasionally Zn) concentrations, which remained, however, adequate. NVS (214 and 642 mT ha⁻¹), digested sewage sludge (ADS) and its compost (24 and 72 mT ha⁻¹), temporarily increased the DTPA-extractability of some elements (NVS: B, Cr; ADS: Cu, Ni, Zn; Compost: Zn) 10–30-fold. The extractabilities of Fe and P increased by up to six times. These increases vanished soon after additive application, supporting the hypothesis of ‘self-attenuation’ by applied biosolids. Our data indicate that long-term application of NVS (and CFA) to calcareous soils poses no heavy metal(loid)s-related threat to the agro-environment. Full article

Fluoxetine and carbamazepine are widely prescribed psychotropic drugs, yet few studies have quantified metal(loid) impurities in these medicines, which may pose health risks to patients. This study aimed to determine concentrations of As, Cd, Cr, Cu, Fe, K, Mg, Mn, P, Pb, Se, and Zn in brand, similar, and generic samples of fluoxetine and carbamazepine marketed in Campo Grande, Brazil. Drug samples were purchased from local pharmacies, digested with acid, and analyzed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES). Results showed that arsenic was detected only in fluoxetine samples, with concentrations ranging from 0.068 to 0.217 mg/kg, all below national and international limits. Phosphorus presented the highest levels, especially in fluoxetine, reaching up to 14,000 mg/kg, and up to 93 mg/kg in carbamazepine. Other elements such as Fe (0.07–3.03 mg/kg), Mg (0.21–259 mg/kg), K (up to 45 mg/kg), Se (up to 1.5 mg/kg), and Zn (up to 4.2 mg/kg) were also quantified, while Cd, Cr, Cu, and Pb were below detection limits. The hazard index (HI) exceeded 1 for all carbamazepine samples and for one brand, two similar, and three generic fluoxetine samples, indicating that the intake of these medications may pose potential health concerns. These findings underscore the need for stricter monitoring of metal(loid) impurities in psychotropic drugs to protect patient safety and ensure regulatory compliance. Full article

The reuse of industrial waste is essential to reduce environmental impact and move towards sustainable development through methods that do not depend on limited resources. To this end, a fertilizer was developed from recycled alkaline batteries, transformed into a useful product rich in zinc and manganese (black mass). The aim is to use industrial waste to create an environmentally safe fertilizer. An experiment was conducted on young citrus plants grafted onto Carrizo rootstock, grown in pots with coconut fiber under greenhouse conditions in Valencia (Spain) for one year (2023–2024). A total of 120 plants were arranged in randomized blocks with three replicates of 10 plants per treatment. Four nutrient solutions derived from the Hoagland formulation were evaluated: control solution without Zn or Mn (SoC), solution with Zn and Mn sulfates (SoH), solution with Zn and Mn sulfates extracted from black mass (BMS), and solution with Zn and Mn lignosulfonate derived from black mass (BMLS). Morphological, growth, physiological, and nutritional parameters were analyzed in March and October. While morphological traits showed no significant differences among treatments, some physiological (stomatal conductance, transpiration) and biochemical variables (chlorophyll, carotenoids, P, K, Mg, and S concentrations) differed significantly depending on the nutrient source. Nevertheless, all plants maintained healthy growth and nutrient levels within optimal ranges, and no signs of phytotoxicity or heavy metal accumulation were detected. Full article

One of the main uses of carob pods ‘algarroba’ (Neltuma spp.) is flour for direct human consumption in indigenous and rural populations of the Gran Chaco. The flour contains antioxidant compounds such as anthocyanins, flavonoids and alkaloids, the concentrations of which can vary according to environmental and genetic factors of the species. This ancestral food is an excellent nutritional alternative as a gluten-free ingredient with antioxidant potential for various culinary preparations. Minerals have essential functions in the human body, so a balanced diet is key to ensuring adequate intake. The composition of carob beans from the Paraguayan Chaco has been little explored in terms of their mineral nutrient content. The aim of this study was to determine the Fe, Cu, Zn and Mn content of carob meal from different species of Neltuma spp. From the Paraguayan Chaco. The mineral elements were determined by atomic absorption spectrometry using official AOAC (2000) methods. Of the samples analysed, N. ruscifolia carob flour had the highest content of Zn (2.2 ± 0.8 mg/100 g), Mn (1.6 ± 0.1 mg/100 g) and Cu (1.5 ± 0.4 mg/100 g). N. nigra and N. alba flour showed higher Fe contents (4 ± 2 and 3 ± 2 mg/100 g, respectively). Consumption of 100 g of P. ruscifolia and P. nigra meal would cover up to 100% of the Recommended Daily Intake (RDI) for Cu and 55–72% of the RDI for Mn. This implies that carob-based foods from Paraguayan Chaco species could have a protective role against oxidative stress if incorporated as functional foods, as well as representing a natural and bioavailable source of antioxidant minerals, which is especially valuable in diets of vulnerable populations with deficiencies or increased requirements, such as in pregnancy, ageing, or chronic diseases. Full article

Stroke remains a leading cause of death and disability worldwide, yet the contribution of elemental imbalance to its pathogenesis is not fully understood. Experimental evidence suggests that disturbances in the concentrations of essential and toxic elements contribute to neuronal injury through excitotoxicity, oxidative stress, and inflammation. In this study, we examined regional concentration in 15 elements (Na, K, Ca, Mg, P, Fe, Zn, Cu, Mn, Se, Cr, V, Pb, Al, B) in the subacute phase of ischemic stroke using the middle cerebral artery occlusion (MCAO) rat model. Male Sprague–Dawley rats underwent MCAO or sham surgery, after which the contralateral cortex, dorsal striatum, and hippocampus were collected seven days post-surgery. Elemental concentrations were determined by inductively coupled plasma-mass spectrometry (ICP-MS) and analyzed by Student’s t-test, cluster analysis, and principal component analysis (PCA). The t-test revealed widespread changes in Ca, while Na was least affected. PCA identified three principal components that explained 81.63% of the variance, with Mn, Zn, Se, K, Mg, Fe, and P contributing most strongly. Cluster analysis distinguished MCAO from sham groups and revealed region-specific responses. Our findings demonstrate long-lasting, region-dependent elemental imbalance after stroke, suggesting a valuable role of elemental profiling. Future investigations should aim to identify elements whose concentrations exhibit alterations not only within central nervous system regions but also in peripheral compartments, such as blood serum, as these changes may hold significant diagnostic and prognostic value. Full article