Search Results (201)

In the context of increasing concern over long-term environmental impacts of closed landfill sites, this study investigates the composition of groundwater and leachate at a municipal waste landfill in southwestern Poland, two decades after its closure. The research, conducted in 2023, aimed to assess groundwater quality using 11 physico-chemical and 13 microplastic indicators. Groundwater and leachate samples were collected seasonally to assess of groundwater quality around landfill, including presence of heavy metals (Cd, Cr⁶⁺, Cu, Pb), PAHs and TOC, and microplastics. The results revealed persistent environmental degradation, with elevated concentrations of total organic carbon (24.8 mg/L) and cadmium (0.0211 mg/L), particularly in the second half of the year. Additionally, PET microplastics were detected in correlation with increased precipitation and leachate generation. These findings indicate that pollutants continue to migrate from the waste deposit into the surrounding groundwater, with seasonal patterns amplifying their presence. The study confirms that even decades after closure, municipal landfills can remain significant sources of both chemical and microplastic contamination, underlining the need for long-term monitoring and remediation strategies to protect groundwater resources. Full article

Milk powder is a key nutritional alternative to breastfeeding, but its thermal properties, which vary with temperature, can affect its quality and shelf life. However, there is little information about the physical and chemical properties of powdered milk in several countries. This dataset contains the result of an analysis of the aflatoxins, macroelement and microelement concentrations, oxidative stability, and fatty acid profile of infant formula milk powder. The concentrations of Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Se, V, and Zn in digested powdered milk samples were quantified through inductively coupled plasma optical emission spectrometry (ICP OES). Thermogravimetry (TG) and differential scanning calorimetry (DSC) were used to estimate the oxidative stability of infant formula milk powder, while the methyl esters of the fatty acids were analyzed by gas chromatography. Most milk samples showed significant concentrations of As (0.5583–1.3101 mg/kg) and Pb (0.2588–0.0847 mg/kg). The concentrations of aflatoxins G2 and B2 are below the limits established by Brazilian regulatory agencies. The thermal degradation behavior of the samples is not the same due to their fatty acid compositions. The data presented may be useful in identifying compounds present in infant milk powder used as a substitute for breast milk and understanding the mechanism of thermal stability and degradation, ensuring food safety for those who consume them. Full article

The Baikal region, including areas with poor environmental conditions, has significant clean background zones. In the summer of 2023, we analyzed the physical and chemical parameters of aerosol particles with different size fractions at Irkutsk and Listvyanka monitoring stations. Reduced wildfires and minimal impact from fuel and energy industries allowed us to observe regional and transboundary pollution transport. A large data array indicated that, during the shift of cyclones from Mongolia to the south of the Baikal region, the concentrations of Na⁺, Ca²⁺, Mg²⁺, K⁺, and Cl⁻ ions increased at the Irkutsk station, dominated by NH₄⁺ and SO₄²⁻. The growth of the ionic concentrations at the Listvyanka station was observed in aerosol particles during the northwesterly transport. When air masses arrived from the southerly direction, the atmosphere was the cleanest. The analysis of 27 elements in aerosols revealed that Al, Fe, Mn, Cu, and Zn made the greatest contribution to air pollution at the Irkutsk station, while Fe, Al, Cu, Cr, Mn, and Ni made the greatest contribution to air pollution at the Listvyanka station. The dynamics of the investigated elements were mainly due to natural processes in the air under various synoptic situations and weather conditions in the region, although anthropogenic factors also affected the formation of aerosol composition wth certain directions of air mass transport. Full article

Delineating soil management zones in cocoa cultivation areas can help optimize production and minimize ecological and environmental risks. This research assessed the spatial distribution of heavy metal concentration and soil fertility indicators in Cross River State, Nigeria, to delineate soil management zones (MZs). A total of n = 63 georeferenced, composite soil samples were collected at the 0–30 cm depth increment, air-dried, and subjected to physicochemical analysis. The soil data were subjected to principal component analysis (PCA), and the selected principal components (PCs) were used for fuzzy c-means clustering analysis to delineate the MZs. The result indicated that soil pH varied from 4.8 (strongly acidic) to 6.3 (slightly acidic), with high average organic carbon contents. The degree of contamination was low, while the ecological risk indicator (RI) of the environment under cocoa cultivation ranged from low risk (RI = 18.24) to moderate risk (RI = 287.15), with moderate risk areas mostly found in patches around the central and upper regions. Higher pH was associated with increased levels of exchangeable Ca, Mg, and K, and TN and OC. Strong spatial dependence was observed for silt, pH, OC, Mg, Zn, Cu, Pb, Cd, Cr, and DC. The result showed the first six principal components (PCs) with eigenvalues >1 accounting for 83.33% of the cumulative variance, and three MZs were derived via the selected six PCs using fuzzy c-means clustering analysis. The results of this study further indicated that MZ3 had the highest pH (6.06), TN (0.24%), OC (2.79%), exchangeable Ca (10.62 cmol/kg), Mg (4.01 cmol/kg), and K (0.12 cmol/kg). These were significantly (p < 0.05) higher than those observed in MZ2 and MZ1, and they represent the most fertile parts of the study area. Furthermore, 40.6% of the study area had marginal soil (i.e., soil under MZ2). Full article

Edible mushrooms are macroscopic fungi that have been recognized as the “new superfoods” due to their high nutritional and medicinal values. The aim of this study was to develop and optimize a method for the wet digestion of edible mushrooms using a closed digestion block for the determination of macro- and micronutrients (Ca, Cr, Cu, Fe, K, Mg, Mn, Ni, and Zn) using microwave-induced plasma emission spectrometry (MIP OES). For the digestion of the samples, a 2³ factorial design was used to evaluate the amount of HNO₃ 65% (m m⁻¹), H₂O₂ 30% (m m⁻¹) and the digestion time, in 500 mg of the sample (dry and crushed) at 200° C. The method was applied to eleven species of edible or medicinal mushrooms (edible cultivated from wild strains, wild edible, and commercials medicinal). The average concentrations (in mg kg⁻¹) showed higher levels of K (1442.85–17,534.97), Mg (1295.40–13,550.72), Fe (11.33–27.38), Zn (28.86–36.09), and Mn (10.22–10.97). This study contributed to the determination of the multi-element composition and nutritional potential of edible mushrooms from Brazil. Full article

With the advancement of industrialization and urbanization, the arbitrary emission of sewage containing TC-tetracycline and hexavalent chromium (Cr(VI)) possesses a serious threat to both ecological–environment and public health. However, developing a low-toxicity and cost-effective photocatalyst for the simultaneous elimination of these two pollutants remains a formidable task. This study devised a photocatalytic sample (CSMX-X) comprised of Copper(I) sulfide (Cu₂S) and Titanium carbide (Ti₃C₂) through a simple solvothermal method and applied it to remove TC-tetracycline and Cr(VI). The CSMX-X not only increases the specific surface area from 2.7 m²·g⁻¹ for pure Cu₂S to 30.65 m²·g⁻¹, but also effectively addresses the problems of insufficient separation efficiency of photogenerated holes and electrons and low carrier density. The photocatalytic efficiency for an individual pollutant (10 mg·L⁻¹ Cr(VI) or 20 mg·L⁻¹ TC-tetracycline) can reach more than 90%, while the removal efficiency for mixed Cr(VI) and TC-tetracycline pollutants only decreases by 12%. Meanwhile, copper leaching levels under different pH conditions (0.032–0.676 mg·L⁻¹) are considerably lower than the 2 mg·L⁻¹ safety standard set by the World Health Organization. This study provides valuable perspectives for constructing Cu₂S-based composite photocatalysts to remove multiple contaminants in real aquatic environments. Full article

Wood ash, a byproduct of woody biomass power generation, has potential as an alternative K fertilizer due to its high K content and pH-raising properties. However, concerns remain about heavy metal contaminants like Cr and the limited understanding of element dynamics in soil–solution–crop systems after wood ash’s application. This study examined the effects of 1% (w/w) wood ash on element dynamics and komatsuna (Brassica rapa var. perviridis) uptake in low-K soil through a pot experiment. XRD was used to analyze mineral composition, SEM-EDS to observe surface and elemental properties, and XANES to examine Cr speciation in wood ash. Soil solution analysis covered macro- and micronutrients, heavy metals, anions, pH, and DOC, while crop element concentrations and aboveground dry weight were also quantified. The chemical speciation of Cu and Cr in a soil solution was modeled using Visual MINTEQ. Wood ash significantly increased K concentrations (from 17 mg/L to 650 mg/L) in the soil solution, along with Ca, Mg, P, and Mo, while reducing Ni, Mn, Zn, and Cd levels. Komatsuna K uptake surged from 123 mg/kg to 559 mg/kg, leading to a 3.31-fold biomass increase. Notably, the Cd concentration in the crops dropped significantly from 0.709 to 0.057 mg/kg, well below the Codex standard of 0.2 mg/kg. Although Cu and Cr concentrations rose in the soil solution, crop uptake remained low due to >99% complexation with fulvic acid, as confirmed by Visual MINTEQ modeling. This study confirms that wood ash is an effective K fertilizer, but emphasizes the need for risk mitigation strategies to ensure safe and sustainable agricultural application. Full article

Five requeijão samples, classified as Brazilian cream cheeses, were developed: one control (without guabiroba pulp (Campomanesia xanthocarpa O. Berg) and four with 5, 10, 15, and 20% (m/m) guabiroba pulp. They were evaluated for pH, water activity (aw), color, texture, multi-mineral composition, carotenoid content, and microstructure. The addition of guabiroba pulp reduced pH and maintained Aw. The samples with 5%, 10%, 15%, and 20% guabiroba pulp presented a yellow–reddish coloration. The formulation with 5% had the lowest values of firmness, resilience, texture, and spreadability. From 10% onwards, an increase in cohesiveness and a reduction in creaminess were observed. The sample with 15% presented better spreadability, while the 20% sample had adhesiveness similar to the control. No traces of Al, As, Cd, Co, Cr, Cu, Fe, Mn, Pb, or Se were detected. The detected elements, in descending order, were Na, Ca, P, S, K, Mg, Sr, and Zn. β-carotene was predominant, with guabiroba pulp enhancing α-carotene, β-carotene, β-cryptoxanthin, and λ-carotene levels, especially at 20% pulp. Microstructure analysis by scanning electron microscopy (SEM) showed no significant differences. These findings highlight the potential of guabiroba pulp as a functional ingredient in requeijão, enhancing its carotenoid profile while maintaining desirable textural and physicochemical properties. Full article

Semi-solid processes of aluminium alloys, characterised by the coexistence of solid and liquid phases, offer advantages in terms of mechanical properties and fatigue resistance, thanks to the more globular microstructure. Thermodynamic models can be used to analyse the solidification behaviour and to predict the solidification window, ΔT. The CALPHAD method enables the calculation of the phases formed during solidification and the optimisation of alloy composition to meet specific industrial requirements. This study aims to assess how thermodynamic properties in both liquid and solid phases affect the ΔT. Initially, the influence of thermodynamic properties of pure components and interaction parameters was analysed in simplified regular binary systems. To compare these findings with real industrial systems, Al-based alloys were examined. Using available databases, the ΔT was estimated via the CALPHAD method adding alloying elements commonly found in secondary Al-alloys. Finally, the same minority alloying elements were added to Al-Si 8 and 11 wt.% alloys, and the corresponding ΔT were calculated. Cr, Fe, Mg, Mn, and Ti increase the ΔT, while Cu, Ni, and Zn decrease it. The obtained results may serve as a valuable tool for interpreting phenomenological observations and understanding the role of minority elements in the semi-solid processing of secondary Al-Si casting alloys. Full article

With the global shift in energy structure and the advancement of the “double carbon” strategy, methanol has gained attention as a clean low-carbon fuel in the engine sector. However, the corrosion–wear coupling failure caused by acidic byproducts, such as methanoic acid and formaldehyde, generated during combustion severely limits the durability of methanol engines. In this study, we employed a systematic approach combining the construction of a corrosion liquid concentration gradient experiment with a full-load and full-speed bench test to elucidate the synergistic corrosion–wear mechanism of core friction pairs (cylinder liner, piston, and piston ring) in methanol-fueled engines. The experiment employed corrosion-resistant gray cast iron (CRGCI), high chromium cast iron (HCCI), and nodular cast iron (NCI) cylinder liners, along with F38MnVS steel and ZL109 aluminum alloy pistons. Piston rings with DLC, PVD, and CKS coatings were also tested. Corrosion kinetic analysis was conducted in a formaldehyde/methanoic acid gradient corrosion solution, with a concentration range of 0.5–2.5% for formaldehyde and 0.01–0.10% for methanoic acid, simulating the combustion products of methanol. The results showed that the corrosion depth of CRGCI was the lowest in low-concentration corrosion solutions, measuring 0.042 and 0.055 μm. The presence of microalloyed Cr/Sn/Cu within its pearlite matrix, along with the directional distribution of flake graphite, effectively inhibited the micro-cell effect. In high-concentration corrosion solutions (#3), HCCI reduced the corrosion depth by 60.7%, resulting in a measurement of 0.232 μm, attributed to the dynamic reconstruction of the Cr₂O₃-Fe₂O₃ composite passive film. Conversely, galvanic action between spherical graphite and the surrounding matrix caused significant corrosion in NCI, with a depth reaching 1.241 μm. The DLC piston coating obstructed the permeation pathway of formate ions due to its amorphous carbon structure. In corrosion solution #3, the recorded weight loss was 0.982 mg, which accounted for only 11.7% of the weight loss observed with the CKS piston coating. Following a 1500 h bench test, the combination of the HCCI cylinder liner and DLC-coated piston ring significantly reduced the wear depth. The average wear amounts at the top and bottom dead centers were 5.537 and 1.337 μm, respectively, representing a reduction of 67.7% compared with CRGCI, where the wear amounts were 17.152 and 4.244 μm. This research confirmed that the HCCI ferrite–Cr carbide matrix eliminated electrochemical heterogeneity, while the DLC piston coating inhibited abrasive wear. Together, these components reduced the wear amount at the top dead center on the push side by 80.1%. Furthermore, mismatches between the thermal expansion coefficients of the F38MnVS steel piston (12–14 × 10⁻⁶/°C) and gray cast iron (11 × 10⁻⁶/°C) resulted in a tolerance exceeding 0.105 mm in the cylinder fitting gap after 3500 h of testing. Notably, the combination of a HCCI matrix and DLC coating successfully maintained the gap within the required range of 50–95 μm. Full article

Houpoea officinalis (H. officinalis) flowers are rich in a spectrum of bioactive compounds and mineral nutrients. The availability and balance of mineral elements directly impact the morphogenesis of flower organs, which play pivotal roles in various physiological and biochemical processes that drive flower development. However, relatively little is known about the changes in mineral elements composition that occur during flower development in H. officinalis. The objective of this study is to analyze the variations of 22 mineral elements contents in pistil, stamens, and petals of H. officinalis flower at four development stages. The amount of mineral elements (Na, Mg, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Sn, Al, Ti, Ga, Cd, Ba, Tl, Pb, and Bi) in these samples was determined using atomic absorption spectroscopy and inductively coupled plasma mass spectrometry. Results showed that H. officinalis flowers are rich in macroelements such as potassium (K, 25.80–48.06 mg/g) and calcium (Ca, 17.27–31.00 mg/g), as well as microelements like zinc (Zn, 445.17–1553.16 μg/g) and iron (Fe, 324.27–622.31 μg/g). Notably, the pistil part is found to harbor a more significant concentration of mineral elements during the early developmental stages of flowers. Correlation analysis and PCA have effectively exposed a pronounced association between the accumulation patterns of mineral elements in H. officinalis flowers and their corresponding developmental stages and organs. These findings will provide more detailed information about the accumulation and distribution of mineral elements in H. officinalis flowers at different development stages and organs, which help to encourage researchers to enhance the flower quality for human consumption. Full article

This research investigates the elemental composition of 78 drinking water samples collected during the summer, autumn, and winter of 2023 in different districts of Almaty city. Seasonal average concentrations and standard deviations were calculated for a range of chemical elements, including arsenic (As), beryllium (Be), cobalt (Co), cadmium (Cd), copper (Cu), lithium (Li), molybdenum (Mo), nickel (Ni), lead (Pb), selenium (Se), uranium (U), mercury (Hg), aluminum (Al), barium (Ba), chromium (Cr), iron (Fe), manganese (Mn), strontium (Sr), vanadium (V), zinc (Zn), calcium (Ca), potassium (K), magnesium (Mg), and sodium (Na), across three distinct datasets. The sites of sampling represent various categories of drinking water sources. The quality of drinking water was assessed by comparing the obtained data with current national, international, and World Health Organization (WHO) standards. Drinking water contaminant indices for the heavy metal groups were calculated and the water quality compliance with the hygienic criteria adopted in the Republic of Kazakhstan was determined. With the exception of two sampling points, the levels of non-carcinogenic risk remained below the acceptable threshold. The predominant pathway for exposure for both adults and children was identified as the oral ingestion of hazardous elements. Carcinogenic risks linked to Ni, Pb, and Cr presence in the drinking water of Almaty were identified, with risk values at the majority of sampling sites categorically classified within the “high risk” designation. No substantial differences in carcinogenic risk levels were detected between adults and children. These results underscore the necessity for enhanced water purification methodologies and ongoing surveillance to protect public health. Full article

This study evaluates the impact of phosphogypsum stacks on the chemical composition of rainwater in the Huelva metropolitan area, a metal-polluted area with high cancer and heart disease mortality rates. A total of 612 rainwater samples were collected using 17 rain gauges located around the study area between January 2021 and December 2022. The pH, conductivity, major ions, and trace metals were detected in the soluble fraction of rainwater. The results revealed spatial variability in the rainwater quality. The highest values of As, Ca²⁺, Cr, F⁻, NH₄⁺, Ni, PO₄³⁻, SO₄²⁻, Sr, and V were detected in rain-gauges near phosphogypsum stacks, exceeding the levels of pH, F⁻, and Ni according to the guideline values for drinking water quality from the WHO. Additionally, other pollution sources also contributed: a regional source (marine factors: Ca²⁺, Cl⁻, K⁺, Mg²⁺, and Na⁺) and a local source (chemical complexes emissions: Co, Cu, Pb, and Zn). A downward trend of most toxic metal(loid) concentrations in wet depositions was detected as the distance to the affected area increased. The findings revealed that phosphogypsum stacks are a relevant source of metal(loid)s with potentially adverse environmental and public health effects that, if replicated, could be relevant for environmental monitoring and policy making. Full article

This research focuses on the structural and bonding characteristics of the Al(111)/CrB2(0001) interface, aiming to clarify the adhesion mechanisms of CrB₂ coatings on aluminum composites. Utilizing first-principles calculations grounded in density functional theory (DFT), we systematically examined the interfacial properties of both clean and doped Al(111)/CrB₂(0001) systems. And key aspects such as binding energy, electron density distribution, and chemical bonding types were thoroughly evaluated. The results demonstrate that the Cr-terminated HCP stacking arrangement at the Al(111)/CrB₂(0001) interface achieves the maximum adhesion work and minimal interfacial energy. This is primarily due to the strong covalent interactions between Al-p and Cr-p orbitals, which contribute to exceptional interfacial strength and stability. Furthermore, the incorporation of Fe, Mg, and Mn at the interface not only markedly improves working adhesion but also effectively lowers the interfacial energy for the Cr-terminated HCP stacking configuration. This phenomenon significantly enhances the overall bonding performance of the Al/CrB₂ system. Conversely, the addition of Cu, Zn, and Si leads to an increase in interfacial energy, negatively impacting the bonding quality. Analysis of binding energies at the doped interface revealed a consistent trend among the elements: Fe > Mn > Mg > Si > Zn > Cu. These findings offer valuable guidance for the design and optimization of Al-based surface coatings with improved performance. Full article

The circular economy practice of using waste to fertilize plants should be more widespread. It is a means to manage natural resources sustainably in agriculture. This approach is in line with organic and sustainable farming strategies, reducing the cultivation costs. Organic waste dumped into a landfill decomposes and emits greenhouse gases. This can be reduced through its application to energy crops, which not only has a positive impact on the environment but also improves the soil quality and increases yields. However, organic waste with increased content of heavy metals, when applied to the soil, can also pose a threat. Using Miscanthus × giganteus M 19 as a test plant, an experiment with a randomized block design was established in four replications in Central–Eastern Poland in 2018. Various combinations of organic waste (municipal sewage sludge and spent mushroom substrate) were applied, with each dose containing 170 kg N ha⁻¹. After three years (in 2020), the soil content of total nitrogen (N_t) and carbon (C_t) was determined by elemental analysis, with the total content of P, K, Ca, Mg, S, Na, Fe, Mn, Mo, Zn, Ni, Pb, Cr, Cd, and Cu determined by optical emission spectrometry, after wet mineralization with aqua regia. For the available forms of P and K, the Egner–Riehm method was used, and the Schachtschabel method was used for the available forms of Mg. The total content of bacteria, actinomycetes, and fungi was also measured. The application of municipal sewage sludge (SS) alone and together with spent mushroom substrate (SMS) improved the microbiological composition of the soil and increased the content of N_t and C_t and the available forms of P₂O₅ and Mg more than the application of SMS alone. SMS did not contaminate the soil with heavy metals. In the third year, their content was higher after SS than after SMS application, namely for Cd by 12.2%, Pb by 18.7%, Cr by 25.3%, Zn by 16.9%, and Ni by 14.7%. Full article