A new insight into the straw decomposition associated with minerals: Promoting straw humification and Cd immobilization.

Organic matter (OM) derived from the decomposition of crop residues plays a key role as a sorbent for cadmium (Cd) immobilization. Few studies have explored the straw decomposition processes with the presence of minerals, and the effect of newly generated organo-mineral complexes on heavy metal adsorption. In this study, we investigated the variations in structure and composition during the rice straw decomposition with or without minerals (goethite and kaolinite), as well as the adsorption behavior and mechanisms by which straw decomposition affects Cd immobilization. The degree of humification of extracted straw organic matter was assessed using excitation-emission matrix (EEM) fluorescence and Ultraviolet-visible spectroscopy (UV-vis), while employing FTIR spectroscopy and XPS to characterize the adsorption mechanisms. The spectra analysis revealed the enrichment of highly aromatic and hydrophobic components, indicating that the degree of straw decomposition and humification were further intensified during incubation. Additionally, the existence of goethite (SG) accelerated the humification of OM. Sorption experiments revealed that the straw humification increased Cd adsorption capacity. Notably, SG exhibited significantly higher adsorption performance compared to the organic matter without minerals (RS) and the existence of kaolinite (SK). Further analysis using FT-IR spectroscopy and XPS verified that the primary mechanisms involved in Cd immobilization were complexion with -OH and -COOH, as well as the formation of Cd-π binds with aromatic C=C on the surface of solid OMs. These findings will facilitate understanding the interactions of the rice straw decomposing with soil minerals and its remediation effect on Cd-contaminated farmland.

The effect of calcium on the removal of Cd2+ in the formation of biogenic secondary iron minerals.

Cadmium is a toxic heavy metal found in acid mine drainage. It hinders plant and animal growth and accumulates in human organs. In this study, through shake flask experiments, an iron-rich, sulphate-rich environment was simulated, and Acidithiobacillus ferrooxidans was used to mediate the formation of secondary high-iron minerals to explore the effect of calcium ions on the removal of Cd2+ from that environment. Four treatment systems were used: "Blank", "Ca2+-30 mg/L", "Fe/K = 3,Ca2+-30 mg/L", and "Fe/K = 3". The results showed that Cd2+ with an initial concentration of 20 mg/L was effectively removed in each treatment system. The removal efficiencies of Cd2+ in each treatment were 23.46%, 18.42%, 52.88%, and 45.76% respectively. The quantity and type of minerals determined the removal efficiency of Cd2+. The Fe/K = 3 treatment system can significantly increase the amount of mineral formation and improve the removal efficiency of Cd2+. In the Ca2+-30 mg/L, Fe/K = 3 treatment system, the biological oxidation ability was the strongest, and the removal effect of Cd2+ was the best under the combined action of K+ and Ca2+. Co-precipitation was the main way to remove Cd2+ during the formation of biogenic secondary iron minerals, and the removal amount was 5.64 to 14.83 times that of adsorption. Biogenetic secondary iron minerals showed high values in repairing heavy metal pollution. This study provides a theoretical basis for treating heavy metals in acid mine drainage.

Understanding microbial biomineralization at the molecular level: recent advances.

Microbial biomineralization is a phenomenon involving deposition of inorganic minerals inside or around microbial cells as a direct consequence of biogeochemical cycling. The microbial metabolic processes often create environmental conditions conducive for the precipitation of silicate, carbonate or phosphate, ferrate forms of ubiquitous inorganic ions. Till date the fundamental mechanisms underpinning two of the major types of microbial biomineralization such as, microbially controlled and microbially induced remains poorly understood. While microbially-controlled mineralization (MCM) depends entirely on the genetic makeup of the cell, microbially-induced mineralization (MIM) is dependent on factors such as cell morphology, cell surface structures and extracellular polymeric substances (EPS). In recent years, the organic template-mediated nucleation of inorganic minerals has been considered as an underlying mechanism based on the principles of solid-state bioinorganic chemistry. The present review thus attempts to provide a comprehensive and critical overview on the recent progress in holistic understanding of both MCM and MIM, which involves, organic-inorganic biomolecular interactions that lead to template formation, biomineral nucleation and crystallization. Also, the operation of specific metabolic pathways and molecular operons in directing microbial biomineralization have been discussed. Unravelling these molecular mechanisms of biomineralization can help in the biomimetic synthesis of minerals for potential therapeutic applications, and facilitating the engineering of microorganisms for commercial production of biominerals.

Unearthing the soil-bacteria nexus to enhance potassium bioavailability for global sustainable agriculture: A mechanistic preview.

Established as a plant macronutrient, potassium (K) substantially bestows plant growth and thus, global food production. It is absorbed by plants as potassium cation (K+) from soil solution, which is enriched through slow-release from soil minerals or addition of soluble fertilizers. Contribution of bioavailable K+ from soil is usually insignificant (< 2 %), although the earth's crust is rich in K-bearing minerals. However, K is fixed largely in interlayer spaces of K-bearing minerals, which can be released by K-solubilizing bacteria (KSB) such as Bacillus, Pseudomonas, Enterobacter, and Acidithiobacillus. The underlying mechanisms of K dissolution by KSB include acidolysis, ion exchange reactions, chelation, complexolysis, and release of various organic and inorganic acids such as citric, oxalic, acetic, gluconic, and tartaric acids. These acids cause disintegration of K-bearing minerals and bring K+ into soil solution that becomes available to the plants. Current literature review updates the scientific information about microbial species, factors, and mechanisms governing the bio-intrusion of K-bearing minerals. Moreover, it explores the potential of KSB not only for K-solubilization but also to enhance bioavailability of phosphorus, nitrogen, and micronutrients, as well as its other beneficial impact on plant growth. Thus, in the context of sustainable agricultural production and global food security, utilization of KSB may facilitate plant nutrient availability, conserve natural resources, and reduce environmental impacts caused by chemical fertilizers.

Taxonomic and functional characterization of biofilms from a photovoltaic panel reveals high genetic and metabolic complexity of the communities.

AIMS: Biofilms are complex microbial cell aggregates that attach to different surfaces in nature, industrial environments, or hospital settings. In photovoltaic panels (PVs), biofilms are related to significant energy conversion losses. In this study, our aim was to characterize the communities of microorganisms and the genes involved in biofilm formation. METHODS AND RESULTS: In this study, biofilm samples collected from a PV system installed in southeastern Brazil were analyzed through shotgun metagenomics, and the microbial communities and genes involved in biofilm formation were investigated. A total of 2030 different genera were identified in the samples, many of which were classified as extremophiles or producers of exopolysaccharides. Bacteria prevailed in the samples (89%), mainly the genera Mucilaginibacter, Microbacterium, Pedobacter, Massilia, and Hymenobacter. The functional annotation revealed >12 000 genes related to biofilm formation and stress response. Genes involved in the iron transport and synthesis of c-di-GMP and c-AMP second messengers were abundant in the samples. The pathways related to these components play a crucial role in biofilm formation and could be promising targets for preventing biofilm formation in the PV. In addition, Raman spectroscopy analysis indicated the presence of hematite, goethite, and ferrite, consistent with the mineralogical composition of the regional soil and metal-resistant bacteria. CONCLUSIONS: Taken together, our findings reveal that PV biofilms are a promising source of microorganisms of industrial interest and genes of central importance in regulating biofilm formation and persistence.

Study on the Bioactive Constituent and Mineral Elements of the Tibetan Medicine E'seguo from Different Regions of Ganzi Prefecture, China.

The Tibetan medicinal fruit E'seguo originates from two species, Malus toringoides (Rehd.) Hughes and Malus transitoria (Batal.) Schneid, both unique to the Hengduan Mountains. These species are predominantly found in high-altitude regions of Ganzi Prefecture, Sichuan Province, particularly in the Xianshui River and Yalong River basins. Malus toringoides (Rehd.) Hughes is far more abundant in both resource quantity and distribution compared to Malus transitoria (Batal.) Schneid. However, the nutritional and medicinal differences between the two remain unclear, which significantly impacts the development and utilization of E'seguo resources. This study aimed to measure the mineral content, nutritional components, and medicinal properties of E'seguo from 12 different regions of Ganzi Prefecture to explore the quality differences between these two species and across different regions. ICP-MS (Inductively Coupled Plasma Mass Spectrometry) was used to determine the mineral content, ultraviolet-visible spectrophotometry and potentiometric titration to analyze nutritional indicators, and HPLC (High-Performance Liquid Chromatography) to measure the medicinal components L-malic acid and 2-O-ß-D-glucopyranosyl-L-ascorbic acid (AA-2ßG). Results indicate that Malus transitoria (Batal.) Schneid contains higher levels of K, Ca, Zn, Mg, and Cu compared to Malus toringoides (Rehd.) Hughes, which has higher Fe and Mn content. Malus toringoides (Rehd.) Hughes from the Kangding and Litang regions showed the highest mineral content, with mineral elements primarily influencing polysaccharide levels, according to Mantel analysis. Nutritional and medicinal analyses revealed that Malus toringoides (Rehd.) Hughes outperformed Malus transitoria (Batal.) Schneid in all metrics except for the sugar-acid ratio. Given the mineral content and taste, Malus transitoria (Batal.) Schneid is better suited for consumption, while Malus toringoides (Rehd.) Hughes has superior medicinal properties, making it more appropriate for medicinal use. In the Malus transitoria (Batal.) Schneid regions, both Luhuo and Daofu are in the Xianshui River basin, with Daofu County producing the higher quality fruit. Among the nine Malus toringoides (Rehd.) Hughes regions, the M10 (Tuoba Township, Ganzi County) near the Yalong River had the highest overall score, followed by M7 (Yade Township, Luhuo County) and M6 (Keke, Xiala Tuo Town, Luhuo County), both of which are near the Xianshui River. In summary, Malus transitoria (Batal.) Schneid generally has higher mineral content, but Malus toringoides (Rehd.) Hughes has larger fruit and higher medicinal value, making the latter more suitable as a medicinal resource. At the same time, the medicinal quality of Xianshui River fruit was higher in the two watersheds of Malus toringoides (Rehd.) Hughes.

Mapping heavy mineral deposits on the coast of the state of Rio Grande do Sul (Brazil) using orbital and proximal remote sensing.

Heavy mineral deposits occur in several coastal areas of the world, formed over a long period due to variations in mean sea level, wave action, and winds. These are the main sources of ilmenite (FeTiO3), which in turn is the source of more than 80% of the TiO2 produced and applied in various industries, most recently in nanotechnology. The present study mapped heavy mineral deposits on the coast of Rio Grande do Sul in southern Brazil using integrated proximal and orbital thermal infrared (TIR) remote sensing techniques. Mineral groups, such as oxides and silicates, have spectral features in the TIR wavelengths. Using laboratory spectroscopy at TIR using Nicolet 6700 Thermo Scientific Spectrometer, we measured the spectral signature of the local sample of heavy minerals (between 8 and 14 µm) and identified a diagnostic spectral feature at 10.75 µm. The signature was resampled to be compatible with the Advanced Spaceborne Thermal Emission Radiometer (ASTER) sensor bandwidth values and used as a reference endmember for the Spectral Angle Mapper (SAM) and Linear Spectral Unmixing (LSU) digital image classification algorithms. Thus, we identified the presence of the reference endmember (heavy minerals) in the pixels of the ASTER scene. In pixels classified by SAM as the presence of heavy minerals, LSU was applied to estimate the surface concentration within the pixel. The results showed a concentration of up to 20% of heavy minerals, with the highest concentration on the beach and dune fields. Opaque minerals such as ilmenite do not have spectral reflectance features in visible, near-infrared, and short-wave infrared, which makes their identification by remote sensing difficult. The present study showed that the integration of proximal and orbital as well as hyperspectral and multispectral thermal data can be considered as an alternative for detecting and mapping heavy minerals in coastal areas.

Comparative analysis of physical traits, mineral compositions, antioxidant contents, and metabolite profiles in five cherry tomato cultivars.

Cherry tomatoes (Solanum lycopersicum var. cerasiforme) are cultivated and consumed worldwide. While numerous cultivars have been bred to enhance fruit quality, few studies have comprehensively evaluated the fruit quality of cherry tomato cultivars. In this study, we assessed fruits of five cherry tomato cultivars (Qianxi, Fengjingling, Fushan88, Yanyu, and Qiyu) at the red ripe stage through detailed analysis of their physical traits, mineral compositions, antioxidant contents, and metabolite profiles. Significant variations were observed among the cultivars in terms of fruit size, shape, firmness, weight, glossiness, and sepal length, with each cultivar displaying unique attributes. Mineral analysis revealed distinct patterns of essential and trace element accumulation, with notable differences in calcium, sodium, manganese, and selenium concentrations. Fenjingling was identified as a selenium enriched cultivar. Analysis of antioxidant contents highlighted Yanyu as particularly rich in vitamin C and Fenjingling as having elevated antioxidant enzyme activities. Metabolomics analysis identified a total number of 3,396 annotated metabolites, and the five cultivars showed distinct metabolomics profiles. Amino acid analysis showed Fushan88 to possess a superior profile, while sweetness and tartness assessments indicated that Yanyu exhibited higher total soluble solids (TSS) and acidity. Notably, red cherry tomato cultivars (Fushan88, Yanyu, and Qiyu) accumulated significantly higher levels of eugenol and α-tomatine, compounds associated with undesirable flavors, compared to pink cultivars (Qianxi and Fengjingling). Taken together, our results provide novel insights into the physical traits, nutritional value, and flavor-associated metabolites of cherry tomatoes, offering knowledge that could be implemented for the breeding, cultivation, and marketing of cherry tomato cultivars.

New insights on the Jacobsite mineral from Bahia and related synthetic manganese-ferrite nanoparticles.

Jacobsite is a relatively rare mineral of composition MnFe2O4, found in Urandi (Bahia State) in Brazil. It is also a common species in the deep-sea manganese nodules, attracting the interest of many mineral-extracting companies. Because of its spinel constitution similar to magnetite, Jacobsite is commonly called a manganese-ferrite. However, the manganese/iron content may vary substantially according to its origin, demanding specific studies in each case. The Jacobsite mineral inspired our laboratory synthesis of the analogous manganese ferrite nanoparticles. The direct synthesis by the coprecipitation method has not been successful; however, it can be carried in the presence of citrate ions, yielding strongly magnetic nanoparticles, with a maximum magnetization of 45.6 emu.g1. Although they were structurally identical to Jacobsite, the mineral from Bahia exhibited a rather weak magnetism, because it involves a ferrimagnetic coupling. For this reason, the synthetic method seems to provide a better way of obtaining strongly magnetic manganese ferrites. These magnetic nanoparticles have been investigated in detail, including their interaction with diatoms, providing interesting magnetic bio-silicate carriers in drug delivery.

Mineral and cross-linking in collagen fibrils: The mechanical behavior of bone tissue at the nano-scale.

The mineralized collagen fibril is the main building block of hard tissues and it directly affects the macroscopic mechanics of biological tissues such as bone. The mechanical behavior of the fibril itself is determined by its structure: the content of collagen molecules, minerals, and cross-links, and the mechanical interactions and properties of these components. Advanced glycation end products (AGEs) form cross-links between tropocollagen molecules within the collagen fibril and are one important factor that is believed to have a major influence on the tissue. For instance, it has been shown that brittleness in bone correlates with increased AGEs densities. However, the underlying nano-scale mechanisms within the mineralized collagen fibril remain unknown. Here, we study the effect of mineral and AGEs cross-linking on fibril deformation and fracture behavior by performing destructive tensile tests using coarse-grained molecular dynamics simulations. Our results demonstrate that after exceeding a critical content of mineral, it induces stiffening of the collagen fibril at high strain levels. We show that mineral morphology and location affect collagen fibril mechanics: The mineral content at which this stiffening occurs depends on the mineral's location and morphology. Further, both, increasing AGEs density and mineral content lead to stiffening and increased peak stresses. At low mineral contents, the mechanical response of the fibril is dominated by the AGEs, while at high mineral contents, the mineral itself determines fibril mechanics.

Decrease in radiocesium adsorption of illite induced by soil organic matter: Quantity or quality?

Organic matter blocks highly selective frayed edge sites on clay minerals and reduces radiocaesium adsorption. The effects of different soil organic matter on Cs adsorption on illite have been investigated. The quantity and quality of soil organic matter was varied by extracting from three contrasting soils and varying extraction conditions. Extracted organic matter was quantified, and analysed using UV and fluorescent spectroscopy. Cs adsorption was markedly lower in soil aqueous extracts, than in simple electrolyte solution at the same ionic strength (IS). Part of the decrease was attributed to soluble soil potassium. After correction for ionic strength and potassium, the relative distribution coefficient of Cs, KdIS,K, decreased with increasing dissolved organic carbon (DOC) concentration. The correlation between KdIS,K and DOC was largely unchanged by taking into account any of the measured spectral parameters. We find no evidence that molecular size and composition of organic coatings determine their effect on the Cs adsorption properties of illite.

Understanding Nanoscale Interactions between Minerals and Microbes: Opportunities for Green Remediation of Contaminated Sites.

In situ contaminant degradation and detoxification mediated by microbes and minerals is an important element of green remediation. Improved understanding of microbe-mineral interactions on the nanoscale offers promising opportunities to further minimize the environmental and energy footprints of site remediation. In this Perspective, we describe new methodologies that take advantage of an array of multidisciplinary tools─including multiomics-based analysis, bioinformatics, machine learning, gene editing, real-time spectroscopic and microscopic analysis, and computational simulations─to identify the key microbial drivers in the real environments, and to characterize in situ the dynamic interplay between minerals and microbes with high spatiotemporal resolutions. We then reflect on how the knowledge gained can be exploited to modulate the binding, electron transfer, and metabolic activities at the microbe-mineral interfaces, to develop new in situ contaminant degradation and detoxication technologies with combined merits of high efficacy, material longevity, and low environmental impacts. Two main strategies are proposed to maximize the synergy between minerals and microbes, including using mineral nanoparticles to enhance the versatility of microorganisms (e.g., tolerance to environmental stresses, growth and metabolism, directed migration, selectivity, and electron transfer), and using microbes to synthesize and regenerate highly dispersed nanostructures with desired structural/surface properties and reactivity.

Mathematical optimization of multilinear and artificial neural network regressions for mineral composition of different tea types infusions.

The objective of this study was to investigate the change in mineral composition depending on tea variety, tea concentration, and steeping time. Four different tea varieties, black Ceylon (BC), black Turkish (BT), green Ceylon (GC), and green Turkish (GT), were used to produce teas at concentrations of 1, 2, and 3%, respectively. These teas were produced using 7 different steeping times: 2, 5, 10, 20, 30, 45, and 60 min. It was also aimed to optimize the regression equations utilizing these factors to identify parameters conducive to maximizing Zn, K, Cu, Mg, Ca, Na, and Fe levels; minimizing Al content, and maintaining Mn level at 5.3 mg/L. The optimal conditions for achieving a Mn content of 5.3 mg/L in black Turkish tea entailed steeping at a concentration of 1.94% for 11.4 min. Variations in K and Mg levels across teas were inconsistent with those observed for other minerals, whereas variations in Al, Cu, Fe, Mn, Na, and Zn levels exhibited a close relationship. Overall, mineral levels in tea can be predicted through regression analysis, and by mathematically optimizing the resultant equations, the requisite conditions for tea production can be determined to achieve maximum, minimum, or target mineral values.

Micronutrients Importance in Cancer Prevention-Minerals.

Cancer, a non-communicable disease with diverse kinds is one of the major global problems with high incidence and no proven method to prevent or treat. Minerals including trace elements are significant micronutrients for preserving the body's typical physiological function. In contrast to extremely processed industrial food, they are rich in natural sources of food and frequently included in nutritional supplements. The daily intake, storage capacities, and homeostasis of micronutrients depend on specific dietary practices in contemporary civilization and can be disturbed by various malignancies. Varied minerals have different effects on the status of cancer depending on how they affect these pathways. The outcomes could differ depending on the mineral such as calcium's supply and the cancer's location. A mineral called zinc helps the immune system function better and aids in wound healing. On the other hand, selenium exhibits anti-oxidant functions and has a dose-response relationship with many cancer types. However, this component can make the patient's condition worse. Although the body produces free radicals when iron is deficient, anaemia affects a patient's quality of life and ability to receive therapy. This chapter compiles the knowledge of minerals connected to unusual accumulation or depletion states in various malignancies.

The Association between Dietary Intakes of Vitamins and Minerals with Tinnitus.

BACKGROUND: Tinnitus is the phantom perception of sound in the ears or head which may result from inflammation of the auditory pathway. A healthy diet consisting of a range of vitamins and minerals may be protective against tinnitus. This study aims to determine the association between intakes of dietary vitamins and minerals and the prevalence and incidence of tinnitus over 10 years. METHODS: In this longitudinal cohort study of 2947 participants (aged ≥ 50 years), 935 (32%) cases of tinnitus were identified and included in prevalence analyses. The remaining 2012 participants were followed to establish 10-year incidence of tinnitus. A validated semi-quantitative food frequency questionnaire was used to determine intakes of dietary vitamins and minerals. RESULTS: No significant associations with tinnitus prevalence were found. However, iron and zinc were significantly associated with incident tinnitus. There was a 44% (multivariate-adjusted HR: 1.44, 95% CI: 1.07-1.93) increased risk of developing incident tinnitus over 10 years with lower zinc intakes and a 35% increased risk with lower iron intakes (multivariate-adjusted HR: 1.35, 95% CI: 1.00-1.80). CONCLUSION: Higher intakes of zinc and iron were significantly associated with lower tinnitus risk. Due to a lack of comparable high-quality data, future research studies should include robust study designs.

Peruvian fava beans for health and food innovation: physicochemical, morphological, nutritional, and techno-functional characterization.

Peruvian fava beans (PFB) are used in traditional cuisine as a nutrient-rich, flavorful, and textural ingredient; however, little is known about their industrial properties. This study evaluated the physicochemical, nutritional, and techno-functional characteristics of PFB varieties: Verde, Quelcao, and Peruanita. PFB exhibited distinct physical characteristics, quality parameters, and morphology. The color patterns of the seed coat and the hardness were the main parameters for distinguishing them. Nutritionally, all three samples exhibited high protein (23.88-24.88 g/100 g), with high proportion of essential amino acids, high dietary fiber (21.74-25.28 g/100 g), and mineral content. They also contain polyphenols (0.79-1.25 mg GAE/g) and flavonoids (0.91-1.06 mg CE/g) with antioxidant potential (16.60-21.01 and 4.68-5.17 µmol TE/g for ABTS and DPPH assays, respectively). Through XRD measurements, the semi-crystalline nature of samples was identified, belonging to the C-type crystalline form. Regarding techno-functionality, PFB flours displayed great foaming capacity, with Verde variety being the most stable. Emulsifying capacity was similar among samples, although Peruanita was more stable during heating. Upon heating with water, PFB flours reached peak viscosities between 175 and 272 cP, and final viscosities between 242 and 384 cP. Quelcao and Verde formed firmer gels after refrigeration. Based on these results, PFB would be useful to developing innovative, nutritious, and healthy products that meet market needs.

Relationship between the mineral content of sugarcane and its genuine derivative, non-centrifugal raw cane sugar.

Non-centrifugal raw cane sugar (NRCS) is a minimally processed product from sugarcane (Saccharum officinarum L). This product contains phytochemical and nutritional compounds that benefit human health. Despite these advantages, NRCS commercialization is hindered by a lack of knowledge about its composition and, consequently, the absence of quality standards. Studies associating the nutritional composition of sugarcane varieties and their genuine products have not yet been found in the literature, and understanding this relationship can help establish quality standards for this product. Therefore, this study evaluated the mineral nutritional composition of genuine derivative NRCS produced from two sugarcane varieties obtained under different agronomic conditions at two stages of maturation to verify the relationships between raw material and the product. The obtained sugarcanes, juices, and bagasse, as well as the produced sugars, were analyzed for mineral content, such as calcium, magnesium, potassium, phosphorus, sulfur, iron, manganese, copper, and zinc, using inductively coupled plasma optical emission spectrometry. Most mineral constituents of sugarcane are in the juice in direct proportions to those in raw sugarcane. Thus, minimally processed food derivatives have nutritional characteristics equivalent to the raw materials. Consumption of NRCS contributes to meeting daily requirements for essential nutrients such as magnesium, copper, potassium, and manganese. For manganese, 25 g of NRCS, like the one produced in this study, can fulfill 22 to 76 % of an adult male's daily mineral requirements. The variation observed in the four NRCS samples, obtained from the same sugarcane variety under different maturation and agronomic conditions, was 250 %. This variation makes establishing quality parameters for mineral or ash content difficult. Therefore, setting mineral content levels for NRCS is inappropriate, as this parameter naturally depends on the raw material.

Insights into the Photochemical Mechanism of Goethite: Roles of Different Types of Surface Hydroxyl Groups in Reactive Oxygen Species Generation and Fe(III) Reduction.

The surface photochemical activity of goethite, which occurs widely in surface soils and sediments, plays a crucial role in the environmental transformation of various pollutants and natural organic matter. This study systemically investigated the mechanism of different types of surface hydroxyl groups on goethite in generating reactive oxygen species (ROSs) and Fe(III) reduction under sunlight irradiation. Surface hydroxyl groups were found to induce photoreductive dissolution of Fe(III) at the goethite-water interface to produce Fe2+(aq), while promoting the production of ROSs. Substitution of the surface hydroxyl groups on goethite by fluoride significantly inhibited the photochemical activity of goethite, demonstrating their important role in photochemical activation of goethite. The results showed that the surface hydroxyl groups (especially the terminating hydroxyl groups, ≡FeOH) led to the formation of Fe(III)-hydroxyl complexes via ligand-metal charge transfer on the goethite surface upon photoexcitation, facilitating the production of Fe2+(aq) and •OH. The bridging hydroxyl groups (≡Fe2OH) were shown to mainly catalyze the production of H2O2, leading to the subsequent light-driven Fenton reaction to produce •OH. These findings provide important insights into the activation of molecular oxygen on the goethite surface driven by sunlight in the environment, and the corresponding degradation of anthropogenic and natural organic compounds caused by the generated ROSs.

Minerals and trace element compositions of some seaweeds from the Marchica lagoon, North-East Mediterranean coast of Morocco.

The objective of the present study was to evaluate the mineral and heavy metals composition of different seaweeds growing in Marchica lagoon. To this end, green seaweeds, red seaweeds, and brown seaweeds were collected from three different stations in the Marchica lagoon. The highest concentration of Ca was measured in Centroceras clavulatum (17.12 ± 0.60), K in Caulerpa prolifera (15.17 ± 0.20), Na in Gracilaria dura (4.16 ± 0.03) and Hypnea musciformis (4.09 ± 0.03), Mg in Ulva rigida (2.80 ± 0.06), and the highest concentration of P was registered in Ulva intestinalis (3658 ± 14). Centroceras clavulatum and Gracilaria dura had the highest Al, Fe, and Sr levels. Cystoseira compressa had the highest As (53.8 mg/kg) and Rb (43 mg/kg). These findings suggest that seaweeds collected from Marchica lagoon could be used as potential sources of minerals and trace elements in seaweed-based products for human and animal nutrition alike.

[Mineral content in freshwater fish in Shaanxi Province in 2021].

OBJECTIVE: To understand the mineral content of freshwater fish produced in Shaanxi Province and evaluate its related nutritional value. METHODS: According to the 2021 Shaanxi Provincial nutrition monitoring plan, the 9 mineral contents of 13 varieties of freshwater fish, produced in Shaanxi province, were determined by inductively coupled plasma atomic emission spectrometry. The nutritional evaluation of mineral elements was carried out by using the index of nutritional quality(INQ) method. Simultaneously, the correlation between 9 minerals and energy was analyzed by SPSS software. RESULTS: Among the 13 fish species, the contents of P and K were highest, with content ranges of 169-255 and 159-373 mg/100 g, respectively, followed by sodium, calcium, magnesium, iron, zinc. The contents of copper and manganese were lowest. The nutritional evaluation showed that the INQ values of P, K and Mg were than 1, the INQ value of P was highest, which was 4.57-8.72. Some fish have INQ values greater than 1 for calcium, iron, copper and zinc. The correlation between the nine minerals was not strong, as a whole. Only some elements have a correlation coefficient greater than 0.6, indicating that there was a synergistic accumulation effect or antagonistic effect in the fish body. CONCLUSION: The dominant mineral elements in different species of fish were different. However, most fish species can be used as high-quality food sources of phosphorus, potassium, magnesium, copper and zinc.