Search Results (62)

Effective arsenic removal is a challenge when smelting high-arsenic copper minerals (HACMs, As > 3.0 wt%). Current arsenic-removal methods for HACM smelting cannot effectively remove arsenic and do not satisfy environmental requirements. This study argues that two-stage filtration based on Fe-25Al porous material and oxygen-controlled roasting is an effective technique for HACM arsenic removal (As = 11.8 wt%). The use of two-stage filtration facilitated double interception: particles larger than 10 μm were mechanically intercepted by the pore channels, and submicron particles (0.1–10 μm) were intercepted by the filter cake. Specifically, in the second stage, the flue gas underwent gradient rapid cooling, and the arsenic in the flue gas rapidly condensed, resulting in efficient arsenic removal. The purity of the condensed product, As₂O_3, was greater than 99%. Moreover, adding sand to the roasted mineral increased the specific surface area from 0.484 m²/g to 0.590 m²/g, reducing the “bottleneck effect” of pores; the addition of carbon further increased the surface area to 2.457 m²/g, inhibiting the formation of arsenate. When the mineral feed rate increased from 50 kg/h to 80 kg/h, the oxygen partial pressure decreased; this effectively inhibited the formation of iron arsenate, and the arsenic removal efficiency increased from 70.20% to 95.61%. The optimized process achieved ≥94% arsenic removal efficiency and ≥76% sulfur-fixation efficiency, with low energy cost. Material balance analysis showed that after arsenic removal, the Cu/Si to Fe/Si ratio of the copper mineral reached 1.5, which is appropriate for immediate subsequent smelting. This study provides a new technological strategy for HACM arsenic removal. Full article

The windowpane oyster (Placuna placenta) is common in coastal areas of the Philippines, thriving in brackish waters. Its shells underpin the local craft industries. While its meat is edible, only small amounts are consumed locally, most going to waste. Utilization of this potential nutrient source is hindered by the lack of information concerning its organic and mineral content, the possible presence of heavy metal ions, and the risk of microbial pathogens. We report extensive analysis of the meat from Placuna placenta, harvested during three different seasons to account for potential variations. This comprises proximate analysis, mineral, antioxidant, and microbial analyses. While considerable seasonal variation was observed, the windowpane oyster was found to be a rich source of protein, fats, minerals, and carbohydrates, comparing well with the meats of other shellfish and land animals. Following pre-cooking (~90 °C, 25–30 min), the standard local method for food preparation, no viable E. coli or Salmonella sp. were detected. Mineral content was broadly similar to that reported in fish, although iron, zinc, and copper were more highly represented, nevertheless, heavy metals were below internationally acceptable levels, with the exception of one of three samples, which was slightly above the only current standard, FSANZ. Whether the arsenic was in the safer organic form, which is commonly the case for shellfish, or the more toxic inorganic form remains to be established. This and the variation of arsenic over time will need to be considered when developing food products. Overall, the meat of the windowpane oyster is a valuable food resource and its current (albeit low-level) use should lower any barriers to its acceptance, making it suitable for commercialization. The present data support its development for high-value food products in urban markets. Full article

Background/Objectives: Trace minerals (TMs), both essential and toxic, are integral to human physiology, participating in enzymatic reactions, oxidative balance, immune function, and the modulation of chronic disease risk. Despite their importance, imbalances due to deficiencies or toxic exposures are widespread globally. While low-income countries often face overt deficiencies and environmental contamination, middle- and high-income populations increasingly deal with subclinical deficits and chronic toxic metal exposure. This review aims to explore the relevance of serum as a matrix for evaluating TM status across diverse clinical and epidemiological, geographic, and demographic settings. Methods: A narrative literature review was conducted focusing on the physiological roles, health impacts, and current biomarker approaches for key essential (e.g., zinc, copper, selenium) and toxic (e.g., lead, mercury, cadmium, arsenic) trace elements. Particular emphasis was placed on studies utilizing serum analysis and on recent advances in multi-element detection using inductively coupled plasma mass spectrometry (ICP-MS). Results: Serum was identified as a versatile and informative matrix for TM assessment, offering advantages in terms of clinical accessibility, biomarker reliability, and capacity for the simultaneous quantification of multiple elements. For essential TMs, serum levels reflect nutritional status with reasonable accuracy. For toxic elements, detection depends on instrument sensitivity, but serum can still provide valuable exposure data. The method’s scalability supports applications ranging from public health surveillance to individualized patient care. Conclusions: Serum trace mineral analysis is a practical and scalable approach for nutritional assessment and exposure monitoring. Integrating it into clinical practice and public health strategies can improve the early detection of imbalances, guide interventions such as nutritional supplementation, dietary modifications, and exposure mitigation efforts. This approach also supports advanced personalized nutrition and preventive care. Full article

The aim of this study is to determine the characteristics of the chemical and mineral composition of sediment layers in a technogenic settling pond. This pond is located on urban land in Berezniki (Perm Krai, Russia), outside the territory of operating industrial facilities, and contains alkaline saline industrial wastes. The origin of this waste was related to sludge from the Solvay soda production process, which had been deposited in this pond over a long period of time. However, along with the soda waste, the pond also received wastewater from other industries. As a result, the accumulated sediment is characterized by variation in morphological properties both in depth and laterally. Five undisturbed columns were taken to study the composition of the accumulated sediment. The obtained samples were analyzed by X-ray diffraction (XRD), synchronous thermal analysis (STA), and X-ray fluorescence (XRF) analysis. The results showed that the mineral composition of bottom sediments in each layer of all studied columns is characterized by the predominance of calcite precipitated from wastewater. Along with calcite, due to the presence of magnesium and sodium in the solution, other carbonates precipitated—dolomite and soda (natron), as well as complex transitional carbonate phases (northupite and trona). Together with carbonate minerals, the chloride salts halite and sylvin, sulfate minerals gypsum and bassanite, and pyrite and nugget sulfur were established. The group of terrigenous mineral components is represented by quartz, feldspars, and aluminosilicates. The chemical composition of sediments in the upper part of the section generally corresponds to the mineral composition. In the lower sediment layers, the role of amorphous phase and non-mineral compounds increased, which was determined by the results of thermal analysis. The content of heavy metals and metalloids also increases in the middle and lower sediment layers. When categorized according to the Igeo value, an excessive degree of contamination (class 6) was observed in all investigated columns for copper content (Igeo 5.2–6.1). Chromium content corresponds to class 5 (Igeo 4.1–4.6), antimony to class 4 (Igeo 3.0–4.0), and lead, arsenic, and vanadium to classes 2 and 3 (moderately polluted and highly polluted). The data obtained on variations in the mineral and chemical composition of sediments represent the initial information for the selection of methods of accumulated waste management. Full article

Typical greisen-type ore samples from northeastern Tasmania were investigated for their critical metal potential. The samples contain zinnwaldite (KLiFe²⁺Al(AlSi₃O₁₀)(F,OH)₂), a lithium-bearing mica that is prone to excessive breakage during conventional processing, leading to the generation of very-fine-sized particles (i.e., slimes, <20 µm), eventually ending up in tailings and resulting in lithium (Li) loss. To assess whether the natural grain size of valuable minerals could be preserved, the samples were processed using electric pulse fragmentation (EPF). The results indicate that EPF preferentially fragmented along mica-rich veins, maintaining coarse grain sizes, although a lower degree of liberation was observed in fine-grained, massive samples. In addition, the critical metal distribution within zinnwaldite was examined using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) techniques. The results reveal differences in Li content between groundmass zinnwaldite and vein-hosted zinnwaldite and that the zinnwaldite contains the critical elements rubidium (Rb), cesium (Cs), and rare earth elements (REEs: La, Ce, Pr, and Nd). Vein-hosted zinnwaldite has a higher average Li content, whereas groundmass mica contains higher concentrations of Rb, Cs, and REEs. Both mica types host inclusions of bismuth–copper–thorium–arsenic (Bi-Cu-Th-As), which are more abundant in vein-hosted mica. In some of the samples, Bi, Cu, Th, and REEs also occur along the mica cleavage planes, as well as in mineral inclusions. The Li, Rb, and Cs grades are comparable to those of European deposits, such as Cínovec and the Zinnwald Lithium Project. Full article

Metal-mining activities inevitably generate contaminants in high quantities, which can pose a risk to soil, water, biota, and humans. This study compares the geochemical properties of waste materials of tailings and waste rock heaps originating from the same high-sulfidation-type epithermal mineralization. Field sampling was conducted in the Recsk Copper Mining Area on the H2 tailings and H7 waste heap, where a total of 48 samples were collected at various depths. The results showed that PTEs were present in varying concentrations and behaved differently in the two waste materials. Copper concentrations were approximately five times higher in H2 tailings (median 1660 mg/kg) than in H7 waste rock (median 347 mg/kg), whereas arsenic was 2.8 times more concentrated in H2 tailings (674 mg/kg vs. 238 mg/kg). Conversely, zinc (114 mg/kg vs. 24 mg/kg), lead (172 mg/kg vs. 42.8 mg/kg), and cadmium (0.83 mg/kg vs. 0.097 mg/kg) show significantly higher concentrations in H7 waste rock. Element mobility analyses revealed that calcium mobility in H7 waste rock (65%) was twice that observed in H2 tailings (32%), with copper showing a threefold higher mobility in H7 despite lower total concentrations. NAG pH values (2.06–3.23) confirmed significant acid-generating potential in both waste types, with the H7 waste rock posing greater immediate environmental risk due to higher element mobility and more advanced weathering indicated by elevated jarosite (4.05%–8.01%) and secondary mineral contents. These findings demonstrate that, despite originating from the same mineralization, the distinct processing histories and physical properties of these materials necessitate unique approaches for successful remediation or secondary raw material extraction. Full article

Background: Associations of antioxidants in prenatal over-the-counter multivitamin-mineral (OTC MVM) supplements with in-utero oxidative stress (OS), antioxidant capacity, and fetal growth are limited. Our objectives were to determine if five fetal ultrasound measurements [biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL), and estimated fetal weight] were associated with OTC MVM supplements and with minerals, biomarkers of OS, and total antioxidant capacity in amniotic fluid (AF). Methods: For this retrospective study, 176 pregnant women who had undergone age-related amniocentesis for genetic testing were included. Questionnaires recorded prenatal OTC MVM supplementation (yes, no). Ultrasound measurements for early (16–20 weeks) and late (32–36 weeks) gestation were extracted from medical charts. AF concentrations for 15 minerals and trace elements and OS biomarkers in AF [nitric oxide (NO), thiobarbituric acid-reactive substances (TBARS), and ferric-reducing antioxidant power (FRAP)] were measured at 12–20 weeks of gestation. Associations of AF minerals, OS biomarkers, and ultrasound measures were analyzed using multiple linear regressions. Results: Positive associations were observed between AF TBARS and seven AF minerals/elements (calcium, copper, magnesium, nickel, strontium, zinc and iron). At 16–20 weeks, AF copper, nickel, strontium, and selenium were positively associated with BPD, HC, AC, and FL, respectively, NO was positively associated with FL, and FRAP was inversely associated with estimated weight. At 32–36 weeks, calcium was positively associated with BPD and chromium and arsenic were negatively with HC. At 16–20 weeks, higher AF FRAP was inversely associated with FL and this exposure continued to be inversely associated with estimated weight at 32–36 weeks. Conclusions: Concentrations of AF minerals, trace elements and biomarkers of OS and in-utero antioxidant capacity were linked to specific ultrasound measurements at different stages of gestation, suggesting a complex interplay among in utero OS, antioxidant capacity, OTC MVM supplements, and fetal growth. Full article

This paper investigated how increased soil temperatures affect soil mineralogy and major and trace element oxide concentrations and the implications of these effects on the mobility of potentially toxic elements (PTEs) in heat-affected soils amended with sewage sludge. The aim was to determine the efficiency of sewage sludge as an immobilizer of PTEs in heat-affected PTE-contaminated soils. Soil samples were heated to 150 °C, 300 °C, 500 °C, and 750 °C and later amended with stabilized sewage sludge at different rates. The concentrations of arsenic (As), chromium (Cr), cobalt (Co), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn) in the different geochemical fractions of the soils were determined before heating, after heating, and after sewage sludge application. Increased soil temperatures affected the mineral assemblage and the concentrations of some major and trace element oxides and the degree of weathering of the soils. These changes were, however, insignificant. The segregation of PTEs into the different soil geochemical fractions before and after heating varied. High soil temperatures resulted in an increase in PTE concentrations in the non-residual fractions of the soil (F1, F2, and F3) with a consequent increase in their mobility. The application of sewage sludge to heated and unheated soils reduced PTE concentrations in the F1 and F2 fractions of both soils, whereas it increased PTE concentrations in the F3 and F4 fractions by up to 30% for As and Cu, 20% for Cd, 25% for Co, 60% for Cr and Ni, 50% for Pb, and 55% for Zn. Significant immobilization of the PTEs was observed in the heat-affected soils that received higher amount of sewage sludge. Fire events could increase the mobility of PTEs in soils, but sewage sludge could still effectively immobilize these PTEs, although it needs to be applied at higher application rates. Full article

Background: In this work the plant growth-promoting (PGP) qualities of the Enterobacter soli strain AF-22b-4245 were studied, including screening tests for PGP, whole genome sequencing (WGS) and genome annotation, and greenhouse experiments on wheat. A gene table was formed that allows us to evaluate the potential PGP properties of a microorganism based on the results of genome-wide sequencing. Results: Based on the results of screening tests and genome annotation, it can be concluded that the E. soli strain AF-22b-4245 strain may have PGP properties, which consist in the ability to survive in arid and saline soils contaminated with copper, arsenic, lead, and chromium soils, form biofilms, produce phytohormones, siderophores, and solubilize phosphorus. Based on the results of experiments on wheat, the E. soli strain AF-22b-4245 increases the efficiency of mineral fertilizers; this effect persists even in conditions of drought and excess salt. It has been shown that E. soli A F22b-4245 can compensate for the lack of soluble phosphorus in the mineral fertilizer, probably by solubilizing insoluble forms in the soil. Full article

Soil, geochemical, microbiological, and archeological studies were conducted at eight settlements dating from the Paleolithic to Late Medieval and Modern Ages near the southern Trans-Urals Mountains, Russia. The forest-steppe landscapes, rivers, and abundant mineral resources have attracted people to the region since ancient times. Cultural layers (CLs) are marked by finds of ceramics fragments, animal bones, stone, and metal tools. The properties of CLs include close-to-neutral pH, being well structured, the absence of salinity, enrichment with exchangeable calcium, and anthropogenic phosphorus (0.2–0.4%). The majority of CLs start at a depth of 3–25 cm, extend to 40–60 cm, and contain 6–10% organic carbon (Corg) in the 0–20 cm layer, reflecting carbon input from modern-day processes. At the Ishkulovo site (0.6–0.8 ka BP), Corg decreases to 1.3% because the CL is below 80 cm, and in the absence of fresh organic material input, carbon has been mineralized. The proximity of sites to deposits of copper, chromium, zinc, and manganese in the Ural Mountains creates natural high-content anomalies in the region, as indicated by their abundance in soils and parent rocks. In the past, these elements were also released into CLs from metal products, ceramic fragments, and raw materials used in their manufacture. The sites are quite far (18–60 km) from the Magnitogorsk Metallurgical plant, but industrial stockpiles of S (technogenic coefficient—Ct 30–87%), and, less often, Cr, Mn, and Sr (Ct 30–40%) accumulated in surface layers. These three factors have led to the concentration of pollutants of the first (arsenic, chromium, lead, and zinc) and second (cobalt, copper, and nickel) hazard classes at CLs, often in quantities 2–5 times higher than values for parent materials and geosphere average content (“Clarke” value), and, and less often, more than the allowable content for human health. This may have influenced their health and behavioral functions. Due to the above properties, chernozems have a high buffering capacity and a strong bond with heavy metals. Therefore, no inhibition of microbes was observed. The microbial biomass of the 0–10 cm layer is high, 520–680 µg C/g, and microbes cause the emission of 1.0 C-CO₂ µg/g of soil per hour. During the ancient settlements’ development, a favorable paleoclimate was noted based on the data cited. This contributed to the spread of productive paleolandscapes, ensuring the development of domestic cattle breeding and agriculture. Full article

Mine tailings are a byproduct of mineral extraction and often pose an environmental challenge due to the contamination of soil and water bodies with dissolved metals. However, this type of waste offers the opportunity for the recovery of valuable metals such as silver (Ag). In the present investigation, an integral analysis of a sample of tailings was carried out, addressing granulometry, elemental composition, neutralization potential (NP), and acid potential (AP), as well as mineralogy, for the dissolution of silver from this type of waste. For this purpose, thiourea (CH₄N₂S) was used as a leaching agent due to its low toxicity, and potassium oxalate (K₂C₂O₄) was used as an organic additive to improve the leaching of the silver phases (argentite and polybasite) present in the tailings. The effects of CH₄N₂S and K₂C₂O₄ concentrations, temperature, and pH on the leaching efficiency of silver (Ag), copper (Cu), iron (Fe), and arsenic (As) were systematically studied. The results revealed that the maximum silver dissolution rate reached 90.75% under optimal conditions: 0.2 M L⁻¹ of thiourea and 0.2 M L⁻¹ of potassium oxalate, at 35 °C and a pH of 2. Full article

Given the severe threats posed by heavy metal pollution to ecological environments and human health, developing effective remediation technologies is of paramount importance. This review delves into the mechanisms, recent advancements, and future prospects of clay mineral-based materials in the adsorption of heavy metals. Clay minerals such as kaolinite, montmorillonite, and bentonite have demonstrated immense potential for the removal of heavy metals from water and soil due to their natural abundance, low cost, and high efficiency. This article summarizes the latest advancements in the adsorption of heavy metals like chromium, copper, lead, cadmium, arsenic and hydrargyrum by clay minerals, while examining how chemical and physical modifications can enhance the adsorption capacity, selectivity, and stability of these minerals. Furthermore, this review discusses how factors such as pH, temperature, and ionic strength affect adsorption efficiency and outlines challenges and future research directions for optimizing clay-based adsorbents in environmental applications. Full article

As a result of changes in copper mineralogy, various treatment options for copper sulfides have been explored, including pretreatment processes aimed at enhancing material permeability and improving the dissolution of valuable minerals. Despite its significance, this topic has only recently gained attention. In this research, a copper concentrate with a high arsenic content was studied, with enargite (Cu₃AsS₄) as the main mineral phase. The objective was to evaluate the effect of pretreatment on copper extraction efficiency prior to leaching. Three key variables were investigated: curing time (0, 5, 10, and 15 days), H₂SO₄ dosage (0, 70, 140, and 210 kg/t), and FeCl₃ concentration (0, 0.5, 1, and 1.5 M). The sample was characterized both before and after pretreatment, revealing the formation of new species such as CuSO₄·5H₂O and Cu₂Cl(OH)₃ under optimal conditions of 15 days curing time, 70 kg/t of H₂SO₄, and 1 M FeCl₃. Copper extraction solely through curing reached 20.79%. The analysis suggests that curing time is the most influential factor in the process, accounting for 46% of the overall contribution. In comparison, sulfuric acid and ferric chloride contribute less, with 20% and 10% contributions, respectively. Full article

Marine macroalgae are organisms rich in bioactive compounds such as polysaccharides, polyphenols, and various minerals. Macroalgae are increasingly being added to the human diet precisely because they contain useful compounds that can also be used in the pharmaceutical industry. Previous research describes their addition to meat products, yogurt, bread, and baby food. However, data on the addition of algae to beer have been scarce. The goal of this work was to produce beer with the addition of brown macroalgae (Fucus virsoides) from the Adriatic Sea. In addition, the basic physical–chemical parameters (color, pH, ethanol, extract, and polyphenols) were determined. The most important premise is the transfer of selenium (Se) to beer, since Se is deficient in human food chain. The transfer of different metals, namely, S (sulfur), Mg (magnesium), P (phosphorus), K (potassium), Ca (calcium), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), Zn (zinc), As (arsenic), Se (selenium), Mo (molybdenum), Cd (cadmium), Hg (mercury), and Pb (lead), from algae to beer was determined using inductively coupled plasma–mass spectrometry (ICP−MS). The results, however, were not satisfactory regarding metal transfer. In particular, Se was detected in beer, but other metals such as As, Cd, and Pb were not. Alga addition contributed to extract values, and the original extract reached 14.3 °P in wort with alga addition, as opposed to 12.8 °P in the control sample. Such high extract content, however, resulted in beer with low alcohol content, <4% v/v for both beers. This could be explained by the high levels of unfermentable extract. pH values showed statistical difference between samples, meaning that the addition of algae significantly affected the pH value of beer, reducing acidity by almost 5%. Full article

The usage of copper (Cu) ores containing low or no arsenic (As) has reduced, and Cu ores containing high levels of As have emerged as vital mineral resources for Cu extraction and processing. The quality of the Cu ores has decreased from 1.6% to approximately 1.0%. The proportion of As to Cu in 15% of Cu resources currently reaches 1:5. However, during the extraction and processing of Cu ores, As presents significant environmental harm. Hence, safely and effectively removing As is paramount in Cu smelting and processing, holding substantial importance in fostering environmentally sustainable practices within the Cu extraction and processing industry. This article consolidates the resource distribution of As-containing Cu (ACC) ores, comprehensively and systematically evaluates the present advancements in extracting techniques for these minerals, and identifies the challenges inherent in pyrometallurgical and wet processes for treating ACC deposits. Pyrometallurgy is a simple primary roasting technique and has widespread applicability in the treatment of various ACC minerals. Its disadvantages are the emission of exhaust gas and the high treatment costs associated with it. The wet arsenic removal method boasts advantages including minimal air pollution and a high resource recovery rate, significantly aiding in Cu concentrate recovery; its major drawback is the production of As-containing wastewater. The hydrometallurgical removal of As from ACC mines involves extracting As through leaching. Recently, biometallurgy has presented innovative solutions using specialized microorganisms to bioleach or bioabsorb As, but large-scale industrial applications still lack specific practical implementation. This review explores the underlying causes of the challenges encountered in processing ACC minerals. Additionally, it highlights pyrometallurgical roasting coupled with high-temperature filtration as a pivotal advancement in the extraction and processing of ACC ores. Full article