Hydroxide Minerals Research Articles

Glycine synthesis from nitrate and glyoxylate mediated by ferroan brucite: An integrated pathway for prebiotic amine synthesis

Amino acids are present in all known life, so identifying the environmental conditions under which they can be synthesized constrains where life on Earth might have formed and where life might be found on other planetary bodies. All known abiotic amino acid syntheses require ammonia, which is only produced in reducing and neutral atmospheres. Here, we demonstrate that the Fe-bearing hydroxide mineral ferroan brucite [Fe0.33,Mg0.67(OH)2] can mediate the reaction of nitrate and glyoxylate to form glycine, the simplest amino acid used in life. Up to 97% of this glycine was detected only after acid digestion of the mineral, demonstrating that it had been strongly partitioned to the mineral. The dicarboxylic amino acid 3-hydroxy aspartate was also detected, which suggests that reactants underwent a mechanism that simultaneously produced mono- and dicarboxylic amino acids. Nitrate can be produced in both neutral and oxidizing atmospheres, so reductive amination of nitrate and glyoxylate on a ferroan brucite surface expands origins of life scenarios. First, it expands the environmental conditions in which life's precursors could form to include oxidizing atmospheres. Second, it demonstrates the ability of ferroan brucite, an abundant, secondary mineral in serpentinizing systems where olivine is partly hydrated, to mediate reductive amination. Finally, the results demonstrate the need to consider mineral-bound products when analyzing samples for abiotic amino acid synthesis.

Characterisation of dissolved organic matter in two contrasting arsenic-prone sites in Kandal Province, Cambodia

Aquifers throughout Asia are impacted by the release of geogenic arsenic (As) into groundwater by microbial reduction of As-bearing Fe(III) (oxy)hydroxide minerals, severely impacting water quality. Groundwater dissolved organic matter (DOM) is likely key to As release, mainly as electron donor or electron shuttles. This study used optical analyses and ultra-high resolution mass spectrometry to examine the sources and composition of groundwater DOM in the As-prone aquifers of Kandal Province, Cambodia, at boreholes with differing host lithology (clay- and sand-dominated). Groundwater and surface water DOM composition were related to As concentrations, to infer the potential role of DOM in promoting As release. Optical and molecular-level analyses indicated an overall dominance of terrestrial-derived DOM in the groundwater samples, with higher freshness index and relative abundance (RA) of aliphatic compounds in clay compared to sand-dominated lithology. Compared to surface water, groundwater DOM had relatively lower O/C ratios and nominal oxidation state of carbon (−0.19 to −0.13 compared to 0.04 for ground and surface water, respectively), with a lower %RA of aliphatic compounds and higher %RA of carboxyl-rich alicyclic molecules, suggesting microbial processing of DOM since percolation into the aquifer. Concentrations of As across both sites were negatively correlated with DOM tryptophan:fulvic-like fluorescence and the %RA of aliphatics, potentially indicating microbial degradation of biolabile DOM in connection with As release, which is consistent with its role as an electron donor source. Together these data support DOM composition as an important control on microbial mediated As release.

Potential for high-grade recovery of rare earth elements and cobalt from acid mine drainage via adsorption to precipitated manganese (IV) oxides

High demand for rare earth elements (REEs) has increased interest in their recovery from unconventional sources, such as acid mine drainage (AMD). AMD contains elevated concentrations of Mn, Fe, and Al, which precipitate as (oxy)hydroxide minerals as pH is raised. These precipitates can remove cations including REEs and Co from solution via sorption and/or coprecipitation. In this study we developed a method to recover these critical minerals by sorption to MnO2, precipitated by oxidation of in situ Mn (II) with added KMnO4 at acidic pH. MnO2 solids were prepared with varying concentrations of KMnO4, SO42−, and Cl−, to elucidate the effects of excess KMnO4, SO42− concentration, and ionic strength on adsorption. When using a stoichiometric ratio of Mn (II) and KMnO4, 100% removal of REEs and Co occurred at approximately pH 3.5, nearly 2 pH units lower than was observed by sorption to Fe and Al hydroxysulfates. When using excess KMnO4 nearly 100% removal of REEs and Co was accomplished at approximately pH 2, although SO42− was found to inhibit REE sorption. From these results, we developed a two-stage process for recovery of REEs from AMD; a preliminary pH adjustment to remove Fe and Al hydroxy-sulfates, followed by adding KMnO4, precipitating MnO2, enabling recovery of REEs and Co. We tested this process in a representative synthetic AMD, achieving a grade of 6.16 mg REEs per g of solid, which is 65 % of the maximum possible grade based on solution composition. Fractionation of REEs was observed, with light REEs (LREEs) preferentially sorbed to MnO2 relative to both medium REEs (MREEs) and heavy REEs (HREEs). In contrast, preferential sorption of HREEs was observed for sorption to Fe and Al oxyhydroxides at all pH ranges. These results suggest the mechanisms of REE sorption differ among the solids and warrant further study.

Formation processes of iron-based layered hydroxide in acid mine drainage and its implications for in-situ arsenate immobilization: Insights and mechanisms

The immobilization of arsenate in transformed minerals depends on their states in acid mine drainage (AMD). In this study, an iron-based layer hydroxide mineral was derived from the transformation of ferrihydrite under co-existing Mg2+ ions in AMD. The immobilization behavior of arsenate on the mineralized LDHm and pre-prepared LDHad was distinguished. 99 % immobilization efficiency was achieved from the mineralized LDHm, maintaining stability without subsequent releases, across initial arsenate concentrations ranging from 10 to 60 mg/L. LDHm outperformed the pre-prepared LDHad, which was synthesized from AMD for arsenate adsorption. Electron energy loss spectroscopy line profiles revealed predominant incorporation of arsenate in the LDHm structure, supported by higher bulk As signals within LDHm. Density functional theory calculations indicated primary arsenate incorporation into LDHm, forming stable bonds with lower energy activation barriers. Importantly, LDHm exhibited a superior electron rearrangement configuration, resulting in enhanced electron state activity and affinity for arsenate. In contrast, arsenate adsorption predominantly occurred on the pre-prepared LDHad, with notable As signals detected particularly at the edges. Adsorption energy evaluation indicated arsenate preference for bonding to Fe3+ sites on LDHad. These findings provide important insights into the role of stable LDH-like minerals for long-term arsenate immobilization in the natural AMD attenuation processes.

ASTER data processing and fusion for alteration minerals and silicification detection: Implications for cupriferous mineralization exploration in the western Anti-Atlas, Morocco

Alteration minerals and silicification are typically associated with a variety of ore mineralizations and could be detected using multispectral remote sensing sensors as indicators for mineral exploration. In this investigation, the Visible Near-Infra-Red (VNIR), Short-Wave Infra-Red (SWIR), and Thermal Infra-Red (TIR) bands of the ASTER satellite sensor derived layers were fused to detect alteration minerals and silicification in east the Kerdous inlier for cupriferous mineralization exploration. Several image processing techniques were executed in the present investigation, namely, Band Ratio (BR), Selective Principal Component Analysis (SPCA) and Constrained Energy Minimization (CEM) techniques. Initially, the BR and SPCA processing results revealed several alteration zones, including argillic, phyllic, dolomitization and silicification as well as iron oxides and hydroxides. Then, these zones were mapped at sub-pixel level using the CEM technique. Pyrophyllite, kaolinite, dolomite, illite, muscovite, montmorillonite, topaz and hematite were revealed displaying a significant distribution in relation with the eastern Amlen region lithological units and previously detected mineral potential zones using HyMap imaging spectroscopy. Mainly, a close spatial association between iron oxides and hydroxide minerals, argillic, and phyllic alteration was detected, as well as a strong silicification was detected around doleritic dykes unit in Jbel Lkest area. A weighted overlay approach was used in the integration of hydrothermal alteration minerals and silicification, which allowed the elaboration of a new mineral alteration map of study area with five alteration intensities. ASTER and the various employed processing techniques allowed a practical and cost effective mapping of alteration features, which corroborates well with field survey and X-ray diffraction analysis. Therefore, ASTER data and the employed processing techniques offers a practical approach for mineral prospection in comparable settings.

Lanthanum Hydroxide and Chronic Kidney Disease Mineral and Bone Disorder: A Rat Model.

To investigate the pharmacological effects and molecular mechanisms of lanthanum hydroxide(LH) on ectopic mineralization of soft tissue and abnormal bone in rats with acute kidney injury(AKI). Wistar rats were modeled by 5/6 nephrectomy. After the operation, the rats were divided into different groups, the biochemical indexes of serum collected at different times. LH was administered by intragastric tube at doses of 0.4, 0.2, and 0.1g/kg, respectively. Rats were sacrificed in the 16th week after LH treatment. Observation of pathological changes in tissues were made by specific staining. Western Blot, Real-Time Quantitative PCR, and immunohistochemistry techniques were used to detect the impact on pathway-related proteins. Compared with the control group (no LH administered), the serum phosphate level of the LH group was significantly reduced (p<0.01), calcification of the thoracic aorta was reduced (p<0.05, p<0.01) (Serum biochemical tests before dosing and during drug treatment cycles), renal fibrosis was improved (p<0.01), nuclear entry of nuclear factor kappa-B (NF-κB) was reduced (p<0.01), and the expression of the smooth muscle protein 22α (SM22α) was significantly increased (p<0.01). The expression of osteogenic marker genes was decreased. In addition, compared with the controls, the receptor activator for nuclear factor-κB ligand/osteoprotegerin (RANKL/OPG) ratio of the femur in the model group was increased (p<0.05). LH can inhibit the occurrence and development of vascular calcification and bone abnormalities in AKI rats by inhibiting the NF-κB and RANKL/OPG signaling pathways.

The Lady with an Ermine – Portrait of Cecilia Gallerani: Research into Leonardo da Vinci’s painting materials and techniques

The Lady with an Ermine is one of the greatest masterpieces by the Italian artist Leonardo da Vinci from around 1489-1490, depicting Cecilia Gallerani, most likely at the time when she was the mistress of Ludovico Sforza, Duke of Milan. This painting belongs to a group of four portraits of women painted by Leonardo along with the Mona Lisa, Ginevra de' Benci and La Belle Ferronnière. It was acquired by Prince Adam Jerzy Czartoryski around 1800 in Italy. In 2012, a group of conservators and scientists from the National Museum in Krakow in collaboration with experts from various institutions in Poland and abroad conducted the sixth research campaign on the painting focusing on its technological aspects. Various techniques were applied to study the materials and methods employed by Leonardo, including technical photography, X-radiography, micro X-ray fluorescence spectrometry. Physico-chemical analyses allowed to identify characteristic pigments employed by Leonardo da Vinci such as vermilion, iron-based earth pigments, lead-tin yellow, lead white, and ultramarine. The background was overpainted in black, most likely before its sale, in the 18th century. The original background most likely consists of an underlayer layer showing slight grey tone modulations obtained using iron oxide or hydroxide mineral earths. The absence of copper-based pigments in the background does not validate the hypothesis of an existing painting hidden under the black repainted zone. A dominance of lead white in brighter parts of the painting was noted, while tonal transitions were achieved using thin layers of an iron-based glaze in the sfumato technique.

Differences Between Heterotrophic and Nitrate-dependent Iron-oxidizing Microbial Communities in Bioreactor Sediment Treating Mine Wastewater

Nitrate-dependent iron oxidation (NDFO) is a novel mechanism for microbial bioremediation of metal and metalloid contaminants. During NDFO, microbes catalyze a redox reaction wherein nitrate is reduced to nitrite and nitrogen gas while Fe(II) is oxidized to solid Fe(III) hydroxide minerals. Metalloid contaminants such as selenium and arsenic have a propensity for adsorption to iron minerals produced during NDFO; some contaminants may also be concurrently bioreduced. A number of bacterial isolates have been shown to be capable of NDFO (e.g., Kappler et al. (2005), Kiskira et al. (2017)), but little work has been done to date characterizing mixed microbial communities performing NDFO. Some autotrophic communities have been characterized, with high relative abundances for strains of Gallionellaceae in both a freshwater sediment enrichment culture and an activated sludge culture (Blöthe and Roden 2009, Tian et al. 2020). In mixotrophic activated sludge cultures, the concentration of Fe(II) amendment was found to significantly impact microbial community composition; these cultures were fed with methanol in addition to Fe(II), and the dominant community members were Methyloversatilis and other methylotrophic strains (Liu et al. 2018). The work presented here examines microbial communities performing NDFO in the context of remediation, and in particular how differences between NDFO and heterotrophic communities may influence remediation effectiveness. This research characterizes and compares microbial communities performing NDFO versus heterotrophic denitrification during removal of selenium and nickel from mining wastewater. Sediment and influent water from a subsurface bioreactor treating mining wastewater were used to construct batch bioreactors, which were amended with selenium and nickel as well as either Fe(II) or methanol to investigate contaminant removal and microbial community composition in NDFO versus heterotrophic microbial communities. Both Fe(II) and methanol reactors removed total aqueous selenium to below the quantification limit, but Fe(II) reactors removed it more rapidly, likely due to adsorption of selenite. For nickel, removal to below the detection limit was achieved with methanol amendment, while Fe(II) amendment resulted in 42-95% removal. This was likely due to precipitation of nickel sulfide during sulfate reduction in methanol-amended reactors. DNA from the batch bioreactors will be sequenced and the results analyzed for differences among communities. Permutational multivariate analysis of variance and non-metric multidimensional scaling will be used to determine significant correlations of community composition with experimental variables, selenium and nickel removal, and NDFO (Roberts 2023, Kruskal 1964). Indicator species analyses (De Cáceres et al. 2010) will be applied to identify taxa found significantly more often (i.e., at a higher relative abundance) in one group of microbial communities than in any other group. The indicator species analysis may reveal whether there are groups of denitrifiers that predominate in NDFO conditions vs. groups that predominate during heterotrophic denitrification. The results of these microbial community analyses, in combination with the geochemical analyses, will improve our understanding of microbial communities performing NDFO in remediation environments.

Multi-metal contaminant mobilizations by natural colloids and nanoparticles in paddy soils during reduction and reoxidation

Naturally-occurring colloids and nanoparticles are crucial in transporting heavy metal contaminants in soil-water systems. However, information on particle-bound metals’ size distribution and elemental composition in paddy soils under redox-fluctuation is scarce. Here, we investigated the mobilization of Cu, Cd, and Pb-containing nanoparticles and colloids in four contaminated soils with distinctive geochemical properties during reduction and subsequent re-oxidation. Using AF4-UV-ICP-MS and STEM-EDS, we observed that particle-bound metals were primarily associated with two sizes ranges: 0.3−40 kDa (F1) and 130 kDa−450 nm (F2), which mainly consisted of organic matter (OM), iron hydroxide and clay minerals. Cu and Pb were more likely bound to colloid than Cd. Colloidal Cu, Pb and Cd accounted for averages of 83.2%, 72.4% and 19.8% of their total concentration in solution (<0.45 µm) during soil reduction, and decreased during soil re-oxidation. This proportion was also positively correlated with aqueous pH and DOC but negatively correlated with Eh. Further quantitative analysis demonstrated that Cu/Cd positively correlated with OM at nanometric scale (F1). This study provides quantitative insights into the size, composition and abundance of polymetallic pollutant-carrying particles in paddy soils during redox fluctuation, and highlights the importance of nanometric interactions between OM and toxic cationic metals for their release.

Description and evolutionary biogeography of the first Miocene jumping spider (Aranaea: Salticidae) from a southern continent

Abstract Examination of a fossil from a Miocene Konservat-Lagerstätte (c. 11–16 Mya) from Australia shows it to be an astioid jumping spider that is here described as Simaetha sp. indet. Fossilization in the iron oxide–hydroxide mineral goethite led to a high-fidelity preservation of not only the exterior, but of the pharyngeal plate and a neuropile in the cephalothorax. The discovery of the fossil supports the molecular-based hypothesis that the Late Oligocene/Early Miocene radiation of astioid genera occurred in Australasia. Modern Asian genera then would be the result of northward migrations from Australia rather than a movement in the other direction. Biogeographically, the Miocene Simaetha fits within the predicted bioclimatic distribution of the genus today, though the bioclimatic requirements of the fossil species are now found in eastern Queensland rather than in central New South Wales. Simaetha, it seems has retained its original bioclimatic profile for 15 Myr, even though climatic and ecological conditions in Australia have changed significantly. The fossil record now shows the independent evolution of modern genera during the Early Miocene in at least five different salticid lineages on two continents. These salticid radiations occurred at a time of planet-wide, rapid climatic and ecological change.

Experimental and molecular modeling investigation on adsorption of gold cyanide complex onto the iron oxide and hydroxide minerals

Complex and refractory gold ores contain high amount of iron oxide and hydroxide minerals, potential adsorbents of gold through preg-robbing phenomenon. In this study, density functional theory (DFT) approach was used to investigate the adsorption of Au(CN)2- complex on hematite, magnetite, and goethite surfaces. The most stable adsorption occurred for goethite when the Au(CN)2- complex was adsorbed from the Au atom along the y axis on the Fe site and the interaction energy was the highest. The following trend was obtained for the preg-robbing potential, which is in good agreement with experiments carried out on synthetic minerals: Goethite > Hematite > Magnetite.

NaHCO3 synergistic electrokinetics extraction of F, P, and Mn from phosphate ore flotation tailings

In this study, the NaHCO3 synergistic electrokinetic method was used to remove F, P, and Mn from phosphate ore flotation tailings (PTs). First, using PHREEQC simulation calculations, the occurrence forms of P, F, and Mn in the PTs were determined. Thereafter, under various electrokinetic treatment conditions, the variation trends between pH and the different forms of various elements in interstitial solutions of the PTs were analyzed. The influence of various electrokinetic treatment methods on conductivity and pH distribution was thoroughly investigated. The difference in P concentration between the cathode and anode chambers was 21.42 mg/L, the removal efficiency of Mn was 71.43 %, and the leaching of F was inhibited. Dissolved impurities migrated to the electrode chamber during electrokinetic treatment primarily because of electromigration and electro-osmotic flow. During the 1.00 M NaHCO3-enhanced electrokinetic treatment in the cathode chambers, in 360 min, P and F concentrations increased from 3.51 mg/L to 57.28 mg/L and 2.073 mg/L to 29.38 mg/L, respectively. Solution-precipitation of hydroxide or carbonate minerals was determined to be an important mechanism for P, F, and Mn stabilization. This study demonstrated that the NaHCO3 synergistic electrokinetic method is suitable for removing F, P, and Mn from PTs. The findings of this study provide insights for developing novel technologies for the clean treatment and high-value utilization of PTs.

Quantifying CO2 Removal at Enhanced Weathering Sites: a Multiproxy Approach.

Enhanced weathering is a carbon dioxide (CO2) mitigation strategy that promises large scale atmospheric CO2 removal. The main challenge associated with enhanced weathering is monitoring, reporting, and verifying (MRV) the amount of carbon removed as a result of enhanced weathering reactions. Here, we study a CO2 mineralization site in Consett, Co. Durham, UK, where steel slags have been weathered in a landscaped deposit for over 40 years. We provide new radiocarbon, δ13C, 87Sr/86Sr, and major element data in waters, calcite precipitates, and soils to quantify the rate of carbon removal. We demonstrate that measuring the radiocarbon activity of CaCO3 deposited in waters draining the slag deposit provides a robust constraint on the carbon source being sequestered (80% from the atmosphere, 2σ = 8%) and use downstream alkalinity measurements to determine the proportion of carbon exported to the ocean. The main phases dissolving in the slag are hydroxide minerals (e.g., portlandite) with minor contributions (<3%) from silicate minerals. We propose a novel method for quantifying carbon removal rates at enhanced weathering sites, which is a function of the radiocarbon-apportioned sources of carbon being sequestered, and the proportion of carbon being exported from the catchment to the oceans.

Atomic-scale modelling of organic matter in soil: adsorption of organic molecules and biopolymers on the hydroxylated α-Al2O3 (0001) surface.

Binding of organic molecules on oxide mineral surfaces is a key process which impacts the fertility and stability of soils. Aluminium oxide and hydroxide minerals are known to strongly bind organic matter. To understand the nature and strength of sorption of organic carbon in soil, we investigated the binding of small organic molecules and larger polysaccharide biomolecules on α-Al2O3 (corundum). We modelled the hydroxylated α-Al2O3 (0001) surface, since these minerals' surfaces are hydroxylated in the natural soil environment. Adsorption was modelled using density functional theory (DFT) with empirical dispersion correction. Small organic molecules (alcohol, amine, amide, ester and carboxylic acid) were found to adsorb on the hydroxylated surface by forming multiple hydrogen bonds with the surface, with carboxylic acid as the most favourable adsorbate. A possible route from hydrogen-bonded to covalently bonded adsorbates was demonstrated, through co-adsorption of the acid adsorbate and a hydroxyl group to a surface aluminium atom. Then we modelled the adsorption of biopolymers, fragments of polysaccharides which naturally occur in soil: cellulose, chitin, chitosan and pectin. These biopolymers were able to adopt a large variety of hydrogen-bonded adsorption configurations. Cellulose, pectin and chitosan could adsorb particularly strongly, and therefore are likely to be stable in soil. This article is part of a discussion meeting issue 'Supercomputing simulations of advanced materials'.

The Mineral Characteristic of Tropical Residual Soil using X-Ray Diffraction (XRD) and Scan Electron Microscopy (SEM)

Volcanic residual soil has unique characteristics due to weather and morphological influences. High temperatures and large amounts of rainfall made the rock weathering intense. Landslide events in volcanic residual soil of West Java are quite serious, more than 100 incidents in total a year. Landslides that occur due to unsaturated conditions on the top of the slope become saturated, so it is very important to conduct research on these tropical residual soil weathering zones to define its mineral characterization using Scan Electron Microscopy (SEM) and X-Ray Diffraction (XRD). From the research it was found that the dominant mineral types and contents were Halloysite and Kaolinite minerals. A typical mineral profile is found that is Goethite and Hematite minerals at the soil surface, Carbonate and Chlorite minerals in deeper soils and large amounts of Feldspar minerals in more deep layers. Because there are unique minerals at each depth of soil weathering, zone classification can be done easily starting from the Initial Leaching Zone at the deepest part where there is Feldspar, the Mineral Washing Zone there is Carbonate and Chlorite and the Oxidation Zone on the surface (there are Oxide and Hydroxide minerals). So that it can form a Residual Tropical Volcanic Weathering Profile.

Crystal Structure of Hydrotalcite Group Mineral—Desautelsite, Mg6MnIII2(OH)16(CO3)·4H2O, and Relationship between Cation Size and In-Plane Unit Cell Parameter

The crystal structure of a naturally occurring layered double hydroxide mineral—desautelsite from San Benito County, California, USA—was refined using single-crystal X-ray diffraction data in the space group R-3m, a = 3.1238(2) Å, c = 23.528(3) Å, V = 198.83(4) Å3, and Z = 3/8. The Mg and Mn cations are disordered occurring in one M site with occupancy Mg0.77Mn0.23. According to the electron microprobe analysis supported by Raman spectroscopy, the empirical formula is Mg6.20(MnIII1.78Al0.01FeIII0.01)Σ1.80(OH)16(CO3)0.90·5.35H2O that shows higher content of interlayer (H2O) molecules in comparison to the ideal formula that also agrees with the structure refinement. The Raman spectroscopy of two samples indicated O–H vibrations (3650/3640 cm−1, ~3500 sh cm−1), symmetric C–O (1055/1057 cm−1), Mg–O–Mg (533/533 cm−1) and Mn–O–Mn (439/438 cm−1) stretching vibrations and lattice vibrations (284/287 cm−1). Summing up our data and that of the current literature, we show a correlation (R2 = 0.91) between the averaged effective ionic radius (x) and a unit cell parameter (y) of hydrotalcite group minerals, y=1.9871x+1.4455. Desautelsite follows this correlation, being the species with one of the largest a unit cell parameters among the group. The correlation can be applied for control of cation intercalation during synthesis.

Improving the chloride binding capacity of alkali activated slag by calcium and aluminum enriched minerals

In this paper, a modified alkali activated slag with improved chloride binding capacity is proposed by introducing calcium and aluminum enriched phases in the binding system. The Ca and Al phases are added in order to promote the formation of AFm type phases in alkali activated system and then transformed into Friedel's salt (Fs) when in contact with chloride. The effects of calcium and alumina type on phase composition, chloride binding behavior, mechanical property of modified alkali activated slag binders are discussed. The results show that the addition of Ca and Al enriched minerals effectively improve the chloride binding capacity of the binder up to 44.4%. The combination of calcium hydroxide and metakaolin shows the highest binding efficiency, followed by calcium nitrite and cement. Metakaolin exhibits better modification on chloride binding capacity than nano alumina. The incorporation of Ca and Al enriched minerals together successfully promotes the formation of AFm type phases (Mc and AFm-NO2) in alkali activated system, while the addition of metakaolin increases the reaction degree and the mean chain length of C-(A)-S-H gels, contributing to the chloride binding capacity. The mechanical properties of alkali activated slag are also improved by adding calcium hydroxide, cement, and alumina enriched minerals, while calcium nitrite exhibits a slight negative effect.

Mineralogy and texture of the iron ore deposits in Tanjung and Pake, Bontocani, South Sulawesi, Indonesia

Iron ore deposits in the Bontocani area are scattered in the form of boulders around the contact zone between granodiorite and limestone, which indicates the skarn type. The study of mineralogy, particularly Fe-bearing minerals in outcrops in the Tanjung and Pake areas, is the goal of this research. The method chosen is fieldwork for detailed analysis of characteristics and relationships between granodiorite intrusions and limestones, as well as representative rock sampling. Furthermore, mineralogy analysis in the laboratory using ore petrography and XRD (X-Ray Diffraction) methods. The iron-bearing minerals found at both of their locations consisted of oxides namely magnetic, hematite, and ilmenite; hydroxide minerals namely goethite; and siderite of the carbonate group. In the Tanjung area as well-found sulfide minerals, namely pyrite, chalcopyrite, covellite, and sphalerite; chromite and manganese of the oxide-hydroxide group; and gangue minerals consisting of calcite, quartz, albite, diopside, hedenbergite, danalite, andradite, and magnesite. Meanwhile, in Pake, the sulfide minerals found are alabandite; oxide minerals namely manganese and pyrolusite; azurite from the hydroxide group; and gangue minerals including calcite, quartz, magnesite, chlorite, andradite. Based on the mineral texture of the ore from mineragraphic analysis, there are textures in the form of open space-filling, replacement, intergrowth, and granular.

Gleichenia nagalingumiae sp. nov., a remarkably well-preserved fossil species with in situ spores from the Miocene of Australia

There are few well-documented members of the Gleicheniaceae from the Cenozoic. Most records are confined to Australia and New Zealand and of sterile material. Gleichenia nagalingumiae sp. nov. was found at McGraths Flat, a recently discovered fossil deposit in central New South Wales (Australia). In this Lagerstätte, fossil preservation in the iron hydroxide mineral goethite provides a remarkable level of subcellular detail. The sori of Gleichenia nagalingumiae sp. nov. occur in a distinct chamber within the lamina, a feature only seen in three extant members of this genus, one from Africa, Madagascar and the Mascarene Islands, another from New Zealand, and the third from Malesia. Gleichenia nagalingumiae sp. nov. is the first record of a taxon with sori in laminar pits from Australia. Recent molecular phylogenies place taxa with sori in laminar pits at the base of the Gleichenia clade. Our discovery suggests that Gleichenia species with sori in laminar pits were more widespread than previously thought. The presence of Gleichenia in this deposit indicates open and disturbed habitats in the region.

Groundwater contamination through potentially harmful metals and its implications in groundwater management

Groundwater contamination through potentially harmful metals (PHMs) is an environmental hazard in Pakistan with significant human health risk reports. The current research was conducted in Sheikhupura District, which is a major industrial site in Punjab, Pakistan. According to the Punjab Directorate of Industries in Pakistan, there are a total of 748 industries in this area. These industries produce a lot of waste and effluent, which contaminate the environment with harmful and toxic materials. Continuous irrigation with industrial effluent and sewage sludge may make groundwater sources vulnerable. Therefore, we collected 243 groundwater samples from community tube wells to investigate the groundwater quality cconcerning PHM contaminations in the study area. This research presents the values of pH, total dissolved solids (TDS), electrical conductivity (EC), and potentially harmful metals (PHMs) like arsenic (As), manganese (Mn), lead (Pb), zinc (Zn), copper (Cu), nickel (Ni), and iron (Fe). PHMs such as As (91%), Mn (14%), Pb (97%), Fe (45%), Zn (15%), in these samples were beyond the permitted limit recommended by the world health organization (WHO). Principal component analysis (PCA) results with total variability of (60%) reveal that the groundwater sources of the study area are contaminated about 30.9, 31.3, and 37.6% of contaminations of groundwater sources of this study are resulted from geogenic sources, anthropogenic sources, or both geogenic and anthropogenic sources, respectively. Such sources may include rock-water interaction, mining actions, agricultural practices, domestic sewage, and industrial effluent in the study area. Saturation indices show that the aquifers of the study area are saturated with lead hydroxide, zinc hydroxide, and goethite minerals, indicating that these minerals have a vital role in the contamination of groundwater. Health risk assessment results predicted that the non-carcinogenic risk (HQ) values of PHMs were found within the permissible limit (&amp;lt;1), except As (1.58E+00) for children, while carcinogenic risk (CR) values of all selected PHMs were lower than the maximum threshold CR value (1 × 10−4).