High Contents Of Cu Research Articles

Metal(oid)s content in High-Andean aquatic systems of the Atacama Desert, Chile: environmental assessment of extreme ecosystems.

The high-Andean mountain of northern Chile host numerous water systems that is in risk due to increased mining activities. Total and dissolved Cd, Cr, Cu, Hg, Ni, Pb, Se, and Zn in water, and Cd, Cu, Fe, Ni, Pb, Zn, As, Mo, Al, and V in sediments of 21 aquatic systems (rivers, saline lakes, salt flats), were studied. The presence of Pb, Cd, and As in waters and sediments could be explained, in part, by mining activities. Waters are not suitable for human consumption or irrigation due to high content of Cu and As and high pH that exceed Chilean water quality guideline values. The use of different background reference values influences noticeably the conclusion related to environmental quality of sediments, measured with different environmental indexes. The local geological background suggest that Cd, Mo, Pb, and As generate some degree of contamination, while the use of unpolluted systems as background suggest that all metals measured in sediments represent a low contamination risk. The use of background values of local unpolluted systems seems to be more realistic than geological formation or Upper Continental Crust reference values to assess the environmental condition. The ecological risk assessment suggests that Cd and As are threat for communities living in these aquatic environments. However, these systems support abundant wildlife, developing unique extreme ecosystems with great potential for non-consumptive use such as special interest tourism and conservation.

Hydrothermal Transformation of Glycerol to Lactic Acid in Alkaline Medium Using Cu Catalysts Obtained from Hydrotalcite-Like Precursors

PurposeThe conversion of glycerol into lactic acid in alkaline medium using heterogeneous catalysts has been highlighted and has proved to be an efficient alternative to the conventional fermentative route. This work investigated the production of lactic acid from glycerol in alkaline medium using copper catalysts obtained from hydrotalcite-like precursors in a continuous flow reaction system and the effect of different copper loading on catalytic behaviors in terms of yield and selectivity to lactic acid.MethodsThe catalysts were synthesized by the coprecipitation method and characterized by XRF, XRD, N2 adsorption–desorption, H2-TPR, CO2-TPD, and the copper dispersion (i.e., metal atoms exposed) was determined by N2O oxidation. The reaction was performed for 30 h at 240 °C, 35 atm, using space velocity (WHSV) of 2 h−1, solution of 10 vol% glycerol, and NaOH/glycerol molar ratio of 0.75.ResultsAlthough the 30CuHT catalyst presented higher BET surface areas, Cu dispersion, and basicity than the 20CuHT catalyst, the best results in terms of glycerol conversion (96.5%) and yield (64%) to lactic acid were obtained in the catalytic test performed with the 20CuHT catalyst.ConclusionThis result may be related to the reaction steps that occur in the liquid phase in the presence of the hydroxyl group (\({\text{OH}}^{-}\) Furthermore, the high content of Cu may favor the hydrogenation of the reaction intermediates (2-hydroxypropenal and pyruvaldehyde), increasing the formation of 1,2-propanediol and consequently reducing the yield of lactic acid. The catalytic activity of the reduced and non-reduced catalysts was investigated, and the results showed that copper oxide also has catalytic activity. However, the reduction of copper oxide provides better results.Graphical Abstract

Analysis of the main physical and chemical characteristics of the vine shoots of three vine varieties from Veneto (Italy)

In Italy the agricultural residues resulting from pruning of vineyards represent a potential energy resource, in particular for the Veneto region which is the second Italian region by vineyard area. This study is aimed at analyzing the main physical and chemical characteristics of vine shoots from the annual pruning of vineyards. This is for their possible use as wood chips in small-medium size power plants. International and European standards for the analysis of biofuels were used to determine the moisture content, heat value, ash content, micro and macro elemental and fibrous fraction (lignin, cellulose, hemicellulose and extractives). The samples were collected from three different vineyards in the Vicenza area. The varieties analyzed were Chardonnay, Glera and Merlot. For each variety, the three different components of vine shoots were compared: internode, node and pith, to investigate in which part of the vine shoot the greatest accumulation of metallic elements deriving from plant protection products occurs. The results show significant differences among the energy parameters of the three varieties and three vine shoot components. In particular, the pith shows low heat value and high ash content while the woody components are characterized by higher energy values. Analysis of the chemical elements showed a high content of Cu and Zn in the wood components, node and internode, causing the high ash content found. In particular, Cu content exceeds the limits set by the reference standard. As regards the analysis of the fibrous fraction, a high content of extractives was found in the pith. These extractives could be one of the explanations why the pith of the three varieties analyzed, especially in Chardonnay, have less lower heat value on dry basis (LHV0) values and high ash contents. On the contrary, the node and internode components have a higher content of cellulose, hemicellulose and lignin. Overall, the vine shoots analyzed have characteristics suitable for a possible energy use. However, due to the high ash and Cu content, according to EN ISO 17225-9:2021 standard these can only be used as wood chips for industrial purposes in large power plants.

Factors conditioning soil PTE contents and the associated health risk in an area with mixed land use.

The study of soil chemical composition and geochemical characterization is of great concern. In 2020, a soil survey of the Ararat region (Armenia) was conducted to study the contents of soil elements (Cr, V, Ti, As, Zn, Cu, Co, Fe, Mn, Ba, Pb, Mo, Ca, and K), identify pollution sources and factors conditioning their spatial distribution patterns, and assess the health risk associated with potentially toxic elements (PTEs). The combined application of compositional data analysis and geospatial mapping allowed to reveal three subsamples with unique chemical signatures. Group I included soils in which Fe, Co, Ti, Mn, V, Ba, Pb, and Zn had mainly a natural origin. Soils of Group II are localized in heavily urbanized and industrialized parts of the region, and their spatial distribution is in line with relatively high contents of Cu and partially As, Cr, and K. The spatial distribution of Group III coincides with positions of soils with relatively high contents of Ca and is in line with the geological features and the locations of stone quarries. The human health risk assessment showed that As contents pose a mono-elemental noncarcinogenic health risk to children in two sites (near the Gold Factory and Tigranashen village), whereas a multi-elemental health risk to children was identified on almost the entire region's territory. Moreover, the comparatively high level of As risk was identified in Group III and linked to the travertine quarries exploitation. The results of this study indicated the need for additional in-depth studies targeting As contents and its unrevealed features linked to the travertine quarries exploitation.

Effective utilization of CuO derived from waste printed circuit boards as a peroxymonosulfate activator for the degradation of reactive blue 19

Waste printed circuit boards (PCBs), a common electronic waste, contain a high content of Cu. For environmental sustainability and economic benefit, it is necessary to recover the Cu as high value-added product instead of discarding it. In this work, Cu from PCBs was successfully recovered as CuO particles with high specific surface area and rich oxygen vacancies through cyclic leaching, chemical precipitation, low temperature aging, and calcination. Compared with CuO prepared from commercial Cu(NO3)2·5H2O, the PCBs-derived CuO (PCBs-CuO) exhibited comparable performance in activating peroxymonosulfate to degrade reactive blue 19, although its crystallinity and phase purity were relatively lower. Additionally, PCBs-CuO had an outstanding pH tolerance (2–12), confirming the practical application potential of PCBs-CuO in the removal of organic contaminants in various wastewater. Moreover, the quenching experiments, electrochemical measurements and electron paramagnetic resonance analysis suggested that 1O2 and ·OH played a significant role in PCBs-CuO/peroxymonosulfate system. The ≡Cu(II) and oxygen vacancies on the surface of PCBs-CuO was mainly responsible for the activation of peroxymonosulfate. This work provides a promising method for recycling metal from waste PCBs into high-effective peroxymonosulfate activator and simultaneously achieving environmental remediation.

Ecological risk assessment and bioaccumulation of trace element, copper, in wheat varieties irrigated with non-conventional water resources in a semi-arid tropics

In developing countries, using non-conventional water for irrigation is a traditional and cost-effective tool. However, its long-term use for agriculture and forestry will led to toxic metal bioaccumulation in plants and soil environment. Copper (Cu) is an essential plant nutrient but its excess accumulation can cause significant issues and risks to human health following food crop consumption. The present study was conducted with the aim to assess impact of copper (Cu) in the five wheat varieties (Seher-2006, Faislabad-2008, Watan, Galaxy-2013, Punjab-2011) at 7-ecological sites during the two growing seasons (2017, 2018). The source of irrigation included the ground water, industrial wastewater and sewage water. The Cu concentrations were subsequently determined via ecological environment (water, soils) and below and above ground plant organs (shoots, roots, and wheat grains) and phytostabilization potential assessment using various pollution indices. Results of this study revealed that mean Cu concentration in different wheat varieties and treatments were varied from 1.53 to 1.07–3.22 mg/kg, 0.58 and 1.94 mg/kg, 0.43–2.39 mg/kg, and 0.23–0.78 mg/kg in amended soil, root, shoot, and grains, respectively. Wheat cultivar, Seher-2006 showed highest Cu transfer from shoot to grain following irrigation with ground water while lowest after industrial water irrigation. High content of Cu was obtained in water and toxicity was higher than the maximum permissible limit. In case of grain and soil samples the copper contents were present within the safe limits. The value of all the indices for Cu were found less than 1 except for bioaccumulation factor and translocation factor that were greater than 1 for some samples. Our results revealed that the studied varieties of wheat crop were safe for consumption but the continuous usage of wastewater for irrigation may pose health risks after many years of consumption because some samples showed the high value for bioaccumulation factor and transfer factor. Wheat varieties possess desirable traits that are vital for phytoremediation purposes.

Phytoremediation Capability and Copper Uptake of Maize (Zea mays L.) in Copper Contaminated Soils

Copper is a frequently used heavy metal worldwide and known to be an essential micronutrient for most living organisms including plants. However, excessive levels of copper in soil may adversely affect plant growth and survival. The continuing introduction of copper to soil, e.g., through excessive utilization of agrochemicals has raised serious environmental concerns throughout the world. A variety of plants have the capability to eliminate pollutants from soil through different mechanisms; however, limited information is reported on phytoremediation potential of maize (Zea mays L.) and its uptake and the accumulation potential in copper-containing soils. The effects of additions of 0, 50, 100, 200 and 300 mg kg−1 of copper to soil on growth parameters of Z. mays, copper uptake from soil and accumulation in roots and shoots, and phytoremediation potential of Z. mays were investigated in this research. Copper content in soil and plant samples were determined using atomic absorption spectrophotometry. The addition of 50 mg kg−1 Cu stimulated Z. mays growth parameters, while higher content of Cu exhibited inhibitory effects of plant growth. Results indicated that roots accumulated significantly higher levels of Cu than shoots in all treatments, suggesting dominancy of phytostabilization mechanism in remediation of Cu-polluted soil by Z. mays. However, translocation of Cu from the roots to the aerial parts enhanced to some extent with copper level in soil. The greatest Cu accumulation capacity of 5210 µg per pot was gained in Z. mays cultivated in soil treated with 200 mg kg−1 copper. Results demonstrated that Z. mays can promisingly remediate low to moderately copper-contaminated soils.

Pollution Characteristics and Driving Factors of Antibiotic Resistance Genes in Dexing Copper Mine

Environmental antibiotic resistance genes (ARGs) are a type of emerging pollutant that has been widely concerning. However, investigations into the contamination of ARGs in mining areas have been scarce. Here, the types, abundances, and influencing factors of ARGs and mobile genetic elements (MGEs) were investigated in soil/sediment of the Dexing copper mine area in June 2019 by using high-throughput quantitative polymerase chain reaction (HT-qPCR). Furthermore, the influence of heavy metals and MGEs factors on ARGs was studied using the multivariate statistical analysis method. The results showed that there were a variety of ARGs in the Dexing copper mining area, and the maximum detected number of ARGs was 70. At the relative abundance level, the relative abundance of individual sites reached 0.085. In the Dexing copper mine, multidrug, MLSB, β-lactamases, tetracycline, and aminoglycoside resistance genes were the dominant ARG classes based on their numbers. The efflux pump was the most dominant resistance mechanism, followed by antibiotic deactivation and cellular protection. There was a significant positive correlation between the abundance of ARGs and MGEs (P<0.05), and TnpA04 and Inti1 were the most important MEGs in Dexing copper mine samples, indicating that horizontal gene transfer might be an important mechanism for the spread of environmental ARGs. The results of Pearson correlation analysis and RDA analysis showed that the content of Cu was significantly positively correlated with the detected numbers and abundance of ARGs (P<0.05), suggesting that the high content of Cu in the Dexing copper mining area might be an important driving factor for the formation of ARGs.

Analysis of heavy metal pollution in Lonicerae Japonicae Flos and its health risk assessment

In this study, the content of five heavy metals(Pb, Cd, As, Hg, and Cu) in 59 batches of Lonicerae Japonicae Flos(LJF) medicinal materials and pieces were determined by inductively coupled plasma mass spectrometry(ICP-MS). The health risk assessment was processed using the maximum estimated daily intake(EDI), target hazard quotients(THQ), and carcinogenic risks(CR) assessment models. With reference to the limit standard for heavy metal content in LJF specified in 2020 edition of Chinese Pharmacopoeia, five batches produced in Hebei were found to contain excessive Pb, and the remaining 54 batches met the specifications, with the unqualified rate of 8.47%. Comparative analysis of heavy metal content in LJF samples from three different producing areas, namely Shandong, Henan, and Hebei showed that the levels of Pb, As, and Hg in LJF from Hebei were significantly higher than those from Henan and Shandong. The samples produced in Shandong contained the highest content of Cd. The samples from Hebei contained the highest content of Cu while those from Shandong had the lowest content of Cu. As demonstrated by health risk assessment based on the EDI, THQ and CR models, these 59 batches of LJF samples did not cause significant health hazards for the exposed population, and there was no potential non-carcinogenic or carcinogenic risk. In conclusion, a few of LJF samples contained excessive heavy metals, so some measures, including controlling production environment, cultivating management mode, and optimizing processing methods, should be taken for ensuring the medication safety of LJF.

Different sources of irrigation water affect heavy metal accumulation in soils and some properties of guava fruits.

Guava is a highly nutritious fruit and widely grown in tropical and sub-tropical regions of the world. Guava orchards are frequently irrigated with contaminated water in different regions of the world. In the present study, fruits of two guava cultivars, i.e., Gola and Surahi were collected from orchards grown in peri-urban areas of Multan, Pakistan, which were irrigated with different sources of irrigation i.e., canal water, tubewell water, and sewage water. The soil (at four different layers), water, and fruit (at harvesting) samples were collected from the orchards for their physical, chemical, and heavy metal analysis. The results revealed that sewage water contained more concentrations of copper (Cu), zinc (Zn), and nickel (Ni) compared to tubewell and canal water. The soil irrigated with sewage water also contained the highest copper, nickel, and zinc contents, while tubewell water-irrigated soils contained the lowest copper, nickel, and zinc contents. As regards different soil layers, the top soil layer (0-15cm) contained the maximum copper, nickel, and zinc contents. In contrast, the minimum copper, nickel, and zinc contents were estimated in the soil layer of 46-60cm depth. The different physiological parameters of guava leaves i.e., photosynthesis (Anet), stomatal conductance (gs), transpiration (E), leaf chlorophyll fluorescence in light (Fv'/Fm') and in dark-acclimated (Fv/Fm), and non-photochemical quenching in dark-acclimated (NPQ) were decreased with sewage water irrigation. Furthermore, the sources of irrigation water significantly altered the different physical and chemical properties of the fruits. It is concluded that sewage water improved the physico-chemical properties of fruits but these also had high concentration of Cu, Ni, and Zn. The cadmium (Cd) was not detected in the fruits of guava cultivars, soils and in different sources of irrigation water. Furthermore, the soil irrigated with sewage water also had high contents of Cu, Ni, and Zn.

Heavy metals abundance and distribution in soil, groundwater and vegetables in parts of Aligarh, Uttar Pradesh, India: implication for human health risk assessment

Anthropogenic activities impact the natural environment, leading to the deterioration of its suitability for living organisms and human health. The present study investigated the concentration and distribution of potentially harmful elements Fe, Cr, Cu, Mn, Ni, Pb and Cd in the soil, groundwater and vegetables, and the consequent human health risk effects. Results revea­led high content of Cu (mean = 331 mg kg–1) and Zn (mean = 348.4 mg kg–1) in the soils and exceeded permissible limits. Geo-accumulation Index (Igeo) values were high in respect of Cu (Igeo = 3.86, 3.16), and Zn (Igeo = 2.4, 1.6), indicating pollution in the industrial training institute (ITI) and Gular areas in Aligarh res­pectively. Groundwater from ITI and Gular recorded maximum content of Cr, Cu, Ni, Mn, Zn, Pb and Cd. Ni and Pb contents exceeded the highest permissible limits. Heavy metal pollution index (HPI) with mean HPI = 806.08 indicated serious groundwater contamination in the ITI and Gular areas. Content of heavy metals in vegetables appeared to be under permissible limit with some exception for Ni and Zn. Finally, the assessment of hazard index (HI) indicated that there was no potential risk to human health upon consumption of vegetables, whereas water ingestion posed serious human health hazard (HI = 2.62) in parts of Aligarh

Intracellular Biotransformation of Cu(II)/Cu(I) Explained High Cu Toxicity to Phytoplankton Chlamydomonas reinhardtii.

The toxicity of Cu is related to its redox species, but the differential toxicity of Cu(II) and Cu(I) remains unknown. In the present study, we developed a novel protocol to simultaneously detect the biologically produced extracellular Cu(I) and internalized Cu(II) in a freshwater phytoplankton Chlamydomonas reinhardtii. The intracellular Cu(I) was further imaged using a fluorometric probe. Combining these pieces of evidence, we demonstrated that Cu(I) dominated the Cu toxicity in algal cells under Fe-deficient conditions. Our results showed that the labile Cu(I) content increased significantly in the low Fe quota cells. Intracellular biotransformation from Cu(II) to Cu(I) rather than the direct uptake of Cu(I) was responsible for the high Cu toxicity. The abnormal biotransformation from Cu(II) to Cu(I) under Fe deficiency was not resulted from the increase of overall Cu bioaccumulation but was likely due to the change of Cu(II) metabolism. High contents of Cu(II) were accumulated in the normal cells and the low Zn quota cells upon Cu exposure but did not induce cell death, further suggesting that Cu(I) dominated the Cu toxicity to the algae. This is the first study to simultaneously consider the effect of Cu(I) and Cu(II) during Cu exposure in phytoplankton. The results uncovered the underlying mechanisms of high Cu toxicity under Fe deficiency and highlighted the critical role of modulation of Cu metabolism in phytoplankton.

Nutritional status of Eucalyptus plantation and chemical attributes of a Ferralsol amended with lime and copper plus zinc

Brazil is a global reference in forest management for wood production (e.g., pulp and solid wood products), and large areas are planted mainly in acidic and poorly fertile soils, with a predominance of Eucalyptus species. Liming is widely adopted in acidic soils in humid tropical regions planted with Eucalyptus to increase the availability of some nutrients and supply Ca and Mg. However, liming decreases the availability of some micronutrients, such as Cu and Zn, depending on the lime content. Copper and Zn fertilization for Eucalyptus is usually intended to replace the amount of micronutrients extracted after wood harvesting. However, few studies have been carried out to investigate the combined effects of lime and Cu plus Zn application on forest plantations in tropical soils. Here, the effects of these factors on soil chemical-attributes, as well as nutrition, and growth performance of Eucalyptus grandis plantations were evaluated on a medium-textured Ferralsol. The stem volume yield improved after liming, regardless of the rate of application, and after Cu plus Zn fertilization. Liming increased soil pH and Ca and Mg availability and reduced Cu and Zn availability. Overall, liming reduced soil Cu and Zn contents in the residual-fraction, while increasing the fraction bound to organic-matter. High contents of Cu and Zn were linked to the organic-matter fraction in the soil under the Eucalyptus plantation. Eucalyptus trees grown in soils amended with lime had higher values for leaf area index and leaf Ca and Mg concentrations but showed reduced Cu and Zn concentrations. The combined application of lime and Cu plus Zn improved Eucalyptus growth, with the higher contribution of lime compared to Cu and Zn. In conclusion, the combined application of lime and Cu plus Zn is a useful strategy to provide balanced nutrition and optimize stem volume yields.

Assessment of the Macro- and Microelement Composition of Fly Ash from 50-Year-Old Ash Dumps in the Middle Urals (Russia)

The paper considers the macro- and micro- element composition of two ash dumps in the Middle Urals, where meadow and forest communities have been spontaneously forming for 50 years, as well as the effect of the plants on the changing composition of the ash. Higher contents of Cu, Co, Sn, Ga, and Yb were found in the deep ash layers of both dumps, while in the upper 20-cm layer, the trace element composition depended on the influence of different plant communities. Higher contents of Sr, Cr, Ni, Sn, and Co were revealed under meadows, and Ba, Zr, and La were found under the forest. The levels of element accumulation in the aboveground and underground parts of dominant plants were revealed. Increased content of Be, Ce, Ga, La, Sc, Y, and Yb was detected in areas where meadow plants were dominant and Zn and Ba in forest areas. The toxic elements Cd and Pb were highly accumulated in both communities, whereas Co was found only in meadows. The studied materials can serve as a base to assess the feasibility of processing and/or utilizing fly ash from ash dumps in the Middle Urals and similar ash dumps in other regions situated in the southern taiga.

Heavy metals in shell fishes of Ojo River, Lagos State, Nigeria

&#x0D; &#x0D; &#x0D; The research examined the accumulations of six heavy metals including chromium (Cr), lead (Pb), iron (Fe), zinc (Zn), cadmium (Cd), and copper (Cu) in water as well as in three male and female species of crab (Cardisoma armatum, Callinectes danae, Callinectes ornatus) sampled from Ojo River in Lagos State of Nigeria. Physico-chemical parameters of the water samples from the River and heavy metal concentrations in the crab species obtained also from the River were examined using standard methods. The results showed that total dissolved solute (TDS), electrical conductivity (EC), salinity, dissolved oxygen, biological oxygen demand and chemical oxygen demand varied significantly along the River course, with TDS and EC being relatively high. Heavy metals detected in the crabs were Fe, Cu and Zn, with Cu being the highest in the species examined. The species C. ornatus presented the highest content of Cu followed by C. armatum and C. danae. The content of heavy metals (mg kg–1) among the crab species showed that Cu (23.47±0.10) &gt; Zn (19.06±0.01) &gt; Fe (16.85±0.01) in all the species except in C. armatum where Fe (1.26±0.44) was &gt; Zn (1.19±0.02). Furthermore, Pb, Cd and Cr were not found in the crabs and this could be associated with the fact that the area consists mainly of residential houses, farms and a few industries. Notably, the content of the heavy metals was larger in the female than the male crabs. This study reported different levels of heavy metal accumulation in male and female species of crabs. Also, the shell fishes from Ojo River might be considered safe for consumption, but the need for continuous monitoring to prevent bioaccumulation is recommended.&#x0D; &#x0D; &#x0D;

Microstructural and Thermo-Mechanical Characterization of Cast NiTiCu20 Shape Memory Alloy.

Among NiTi-based alloys, one of the most promising and exploited alloys is NiTiCu, since the addition of Cu in substitution of Ni in the binary equiatomic NiTi has a significant influence on the martensitic transformation and the thermomechanical properties of the system. A high content of Cu improves the damping properties at the expense of phase homogeneity and workability. The present study focuses on an alloy with a high copper content, i.e., 20 at.%. For this specific composition, the correlation between the thermal treatments, microstructure, formation of secondary phases, and damping properties are investigated by several analyses. The microscopic observation, together with the compositional analysis, allowed the determination of four different phases in the alloy. Both the calorimetry and dynamic thermo mechanical measurements, which confirmed the high damping ability of the alloy, provided a characterization of the martensitic transition. Finally, the electron backscatter diffraction (EBSD) analysis detected the different crystallographic structures (i.e., cubic austenite, orthorhombic martensite, and cubic (face-centered) NiTi2) and their orientation in the different phases. Therefore, the present work aims to improve the knowledge of the role of secondary phases in the optimization of the NiTiCu20 alloy as a valuable alternative to typical alloys used for damping purposes.

CuMn2O4 Spinel Nanoflakes for Amperometric Detection of Hydrogen Peroxide

The rapid and accurate detection of hydrogen peroxide (H2O2) has recently been a fascinating research topic in electrochemical sensing. Herein, spinel CuMn2O4 nanoflakes were synthesized through coprecipitation and pyrolysis methods and then drop-coated onto the surface of a bare glassy carbon electrode (GCE), successfully generating an enzymatic-free electrochemical sensor (CuMn2O4/GCE) for good amperometric detection ability of H2O2. In comparison with the reported spinel AB2O4-based electrocatalysts in a phosphate buffer solution, the CuMn2O4/GCE sensor exhibits a high sensitivity of 3.420 A M–1 cm–2 and a low detection limit of 12 nM. This excellent sensing performance is mainly derived from the inherent porous structure and the large electrochemical active area of spinel CuMn2O4 nanoflakes, as well as the synergistic effect between Cu and Mn that facilitates electron transfer and increases active sites. Especially, the high contents of Cu+ and Mn3+ ions in the nanocatalyst are useful for promoting the capture and reduction of trace H2O2. In addition, the CuMn2O4/GCE sensor presents a satisfactory recovery in monitoring H2O2 derived from rat serum, commercial milk, and disinfectors, indicating its potential applications in related environmental, food, and biological fields.

Quasicrystalline phases in conventionally cast Fe-containing Al-Cu-Mn alloys and its evolution during the annealing at 530°C

This study investigates the stabilization of icosahedral quasicrystal (I-phase) in conventionally cast Fe-containing Al-Cu-Mn alloys and its decomposition to decagonal quasicrystal (D-phase) by annealing at 530°C for different time durations (16–48 h). It is observed that in the as-cast Al-Cu-Mn-Fe alloy with a high content of Cu and Mn, I-phase is present in the form of a composite structure with a chemical constituent of Al65Cu20(Mn,Fe)15. Grain boundaries and triple junctions are partially or pseudopartically wetted by θ-Al2Cu phase and completely wetted by T-Al20Cu2Mn3 phase, respectively. Upon annealing at 530°C for different time durations, I-phase, by consuming θ-Al2Cu phase in the grain boundary, transforms into D-phase and T-Al20Cu2Mn3 phase without having Fe. Hence, Fe plays a key role in the stabilization of I-phase in the conventionally cast Al-Cu-Mn alloys but does not take part in its transformation to D-phase and T-Al20Cu2Mn3 phase.

Assessment of Lichens as Biomonitors of Heavy Metal Pollution in Selected Mining Area, Slovakia

Lichens have widely been used as bioindicators to reflect the quality of the environment. The present study was conducted to investigate the lichens diversity that grows on the surface of waste heaps from an abandoned old copper mine in Mlynky, Slovakia. In spite of the heavy metalcontaminated environment, we documented twenty species of lichens in the selected site. Taxonomically the most numerous group were represented by Cladonia with seven species, as well other species; namely, Acarospora fuscata, Cetraria islandica, Dermatocarpon miniatum, Hypogymnia physodes, Hypogymnia tubulosa, Lecanora subaurea, Lepraria incana, Physcia aipolia, Porpidia macrocarpa, Pseudevernia furfuracea, Rhizocarpon geographicum and Xanthoria parietina. The content of selected heavy metals (Cu, Fe, and Zn) in the predominant lichens Cetraria islandica, Cladonia digitata, Cladonia pyxidata, Hypogymnia physodes and Pseudevernia furfuracea were analyzed. The highest content of Cu, Fe, and Zn was found in Cladonia pyxidata collected from mine-spoil heaps with concentration 46 ± 4.4, 82.5 ± 22.6, 4.8 ± 1.6 mg/kg, respectively. Interestingly, Cladonia pyxidata collected from the forest surrounding the location showed 15 times lower concentration for Cu. Additionally, similar results were found for Fe and Zn.

Metal anomalies in till in the Sarvlaxviken area, Lovisa, southern Finland

Geochemical investigations of till is a widely used method in metal exploration as the till commonly inherits the geochemical signature (including the metal contents) of the parent bedrock. In this investigation, over 2000 till samples were collected in the Sarvlaxviken area, southern Finland, where several polymetallic (Cu, Zn, Pb, As, Sn, W and In) veins recently have been discovered in Proterozoic crust along the border between Late Svecofennian granites and the Wiborg Batholith. The bedrock is commonly covered by compact and poorly sorted basal till, formed during the Late Weichselian glaciation event. Several glacial-transported boulders, with high contents of Cu, Zn, As, Sn, Mo and Bi and derived from the local bedrock, have also been discovered on top of the till and provide evidence for concealed mineralisation in the local bedrock under the till cover. The frequent distribution of till in the Sarvlaxviken area provides excellent conditions for the search of such hidden mineralisation by means of systematic till sampling, even if large farm field areas, composed of clay-rich sediments, and seawater-covered areas (Sarvlaxviken bay), had to be avoided in the sampling program. The till samples were collected during university courses and training programs led by the authors and were analysed in a cost-efficient and certified laboratory. Obtained geochemical data were statistically processed by using K-means clustering algorithms which can be used to treat large sets of geochemical data. The results provided anomalies that mainly occur in till with a thickness of <1 m and are considered to be derived from a local bedrock source. The discovered anomalies provide strong evidence for numerous undiscovered veins beneath the till cover.