Soil phosphorus fractionations as affected by cropping systems in the central mid-hills region of Nepal.

Soil plays a critical role as the primary reservoir of phosphorus (P) in terrestrial ecosystems. Sequential fractionation has been extensively utilized to gain insights into the characteristics and dynamics of soil P. However, there is a knowledge gap regarding the different P pools in Nepalese soils. Therefore, this study aimed to investigate the impact of cropping systems on soil P fractions in the central mid-hills of Nepal. The study focused on four cropping systems: vegetable, fruit, rice, and maize-based systems, which exhibited variations in nutrient management, topography, and cropping intensity. A total of 240 soil samples (60 samples from each cropping system) were collected from multiple sites within the central mid-hill region. Standard analytical methods were used to determine the general parameters of the soils, while the sequential fractionation method was employed to assess the organic and inorganic P pools. The results indicated that the effect of cropping systems on soil pH, calcium carbonate (CaCO3) content, and the proportion of sand, silt, and clay was not statistically significant in terms of general parameters. However, significant differences were observed among the different cropping systems in organic matter (OM), electrical conductivity (EC), cation exchange capacity (CEC), and available phosphorus. Similarly, in terms of inorganic phosphorus fractions, loosely bound P (LB-P), aluminum bound P (Al-P), iron bound P (Fe-P), and reductant soluble P (RS-P) were significantly affected, while calcium bound P (Ca-P) did not show a significant difference. Furthermore, in terms of organic phosphorus fractions, labile organic P (L-Po), fluvic acid organic P (FA-Po), and non-labile organic P (NL-Po) exhibited significant differences, whereas moderately labile organic P (ML-Po) and humic acid organic P (HA-Po) did not show a significant difference. Additionally, reductant soluble P showed a significant difference, while total P did not differ significantly. The vegetable-based system exhibited higher levels of the majority of P fractions, followed by the fruit-based, maize-based, and rice-based systems. These findings emphasize the importance of considering cropping systems and their response to different phosphorus pools, as this knowledge can contribute to the development of improved soil phosphorus management strategies and promote sustainable agricultural practices in the region.

The impact of aragonite saturation variability on shelled pteropods: An attribution study in the California Current System.

Observations from the California Current System (CalCS) indicate that the long-term trend in ocean acidification (OA) and the naturally occurring corrosive conditions for the CaCO3 mineral aragonite (saturation state Ω < 1) have a damaging effect on shelled pteropods, a keystone group of calcifying organisms in the CalCS. Concern is heightened by recent findings suggesting that shell formation and developmental progress are already impacted when Ω falls below 1.5. Here, we quantify the impact of low Ω conditions on pteropods using an individual-based model (IBM) with life-stage-specific mortality, growth, and behavior in a high-resolution regional hindcast simulation of the CalCS between 1984 and 2019. Special attention is paid to attributing this impact to different processes that lead to such low Ω conditions, namely natural variability, long-term trend, and extreme events. We find that much of the observed damage in the CalCS, and specifically >70% of the shell CaCO3 loss, is due to the pteropods' exposure to naturally occurring low Ω conditions as a result of their diel vertical migration (DVM). Over the hindcast period, their exposure to damaging waters (Ω < 1.5) increases from 9% to 49%, doubling their shell CaCO3 loss, and increasing their mortality by ~40%. Most of this increased exposure is due to the shoaling of low Ω waters driven by the long-term trend in OA. Extreme OA events amplify this increase by ~40%. Our approach can quantify the health of pteropod populations under shifting environmental conditions, and attribute changes in fitness or population structure to changes in the stressor landscape across hierarchical time scales.

Limestone water mixing process and hydrogen and oxygen stable isotope fractionation response under mining action.

North China type coalfield are gradually mining deep, and the mixing of groundwater is intensified. Hydrogen and oxygen isotopes are important elements for tracing groundwater movement. The fractionation response mechanism under mining conditions is not clear. In this paper, combined with numerical simulation, MixSIAR isotope mixing model and other methods, according to the δD, δ18O and hydrochemical information of various water bodies, the impact of coal mining on hydrogen and oxygen isotope fractionation is analyzed from multiple perspectives. The results show that summer soil water is the main source of recharge for limestone water, accounting for 30.7%-41.5%, and the Zhan River is the main source of recharge for limestone water. Before groundwater recharge, evaporation leads to the increase of δ18O in surface water by 0.31‰-5.58‰, water loss by 1.81%-28.00%, the increase of δ18O in soil water by 0.47‰-6.33‰, and water loss by 2.74%-35.80%. Compared with the coal mining layer, the degree of hydrogen and oxygen isotope drift and water-rock interaction in the coal mine stopping layer are significantly improved. The results of numerical simulation show that the pumping activity reduces the 18O concentration in the mining layer. The ion ratio is used as a new variable to eliminate the influence of water-rock interaction when calculating the mixing ratio. The results show that the limestone water is in a state of receiving external recharge, and mixing effect increases the δ18O in limestone water by 0.86‰ on average, and the δD increases by 0.72‰ on average. The research results explain the controlled process of hydrogen and oxygen isotope fractionation under mining conditions, which is of great significance to coal mine safety production.

Geochemical, mineralogical records, and statistical approaches in establishing sedimentary in the environment of a Mediterranean coastal system: case of Sebkha El-Guettiate (southeastern Tunisia).

The current study was conducted within the context of the Holocene era in Sebkha El-Guettiate, located in southeastern Tunisia. The aim was to determine the factors influencing the geochemical and mineralogical composition of sediments and to elucidate the sedimentary characteristics of the Holocene within the Sebkha core. We examined a sediment core extending 100 cm from this Sebkha, subjecting it to comprehensive analysis to uncover its sedimentological, mineralogical, and geochemical properties. Several techniques were employed to strengthen and validate the connections between geochemical and mineralogical analyses, including X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and infrared (IR) spectroscopy, among others. Furthermore, statistical analyses utilizing principal component analysis (PCA) were applied to the results of the geochemical and mineralogical studies, aiding in the identification of patterns and relationships. A comprehensive mineralogical assessment of the core's sediments revealed the presence and interpretation of carbonate minerals, evaporite minerals, and detrital minerals. Through the application of infrared (IR) spectrometer techniques to all sediment samples, we gained insight into the mineralogical components and the distribution of key elements such as quartz, kaolinite, calcite, feldspar, and organic carbon. The geochemical composition demonstrated a clear dominance of silica (SiO2), accompanied by fluctuations in carbonate percentages (CaCO3). The prominent major elements, primarily magnesium (Mg) and calcium (Ca) originating from dolomitization, sodium (Na) and chlorine (Cl) from halite, and calcium (Ca) from gypsum, exhibited varying levels. Results from Rock-Eval 6 pyrolysis indicated that the organic matter within the sediments is generally a mixture of terrestrial and aquatic origins. This study provides practical information that underscores the diverse origins contributing to Sebkha sediment formation, often influenced by saline systems.

Structural and Compositional Changes in Two Marine Shell Traditional Chinese Medicines: A Comparative Analysis Pre- and Post-Calcination.

BACKGROUND: Arcae concha and Meretricis concha cyclinae concha are two marine shellfish herbs with similar composition and efficacy, which are usually calcined and used clinically. OBJECTIVE: This study investigated variations in the inorganic and organic components of Arcae concha and Meretricis concha cyclinae concha from different production regions, both Arcae concha and Meretricis concha cyclinae concha. The aim was to enhance the understanding of these two types of marine shell traditional Chinese medicine (msTCM) and provide a foundation for their future development and application. METHOD: Spectroscopic techniques, including infrared spectroscopy, X-ray spectroscopy, and X-ray fluorescence spectroscopy, were used to analyze the calcium carbonate (CaCO3) crystal and trace elements. Thermogravimetric analysis was used to investigate the decomposition process during heating. The proteins were quantified using the BCA protein assay kit. Principal component analysis (PCA) was used to classify inorganic elements in the two marine shellfish traditional Chinese medicines. RESULTS: No significant differences were found among the various production regions. The crystal structure of CaCO3 in the raw products was aragonite, but it transformed into calcite after calcination. The contents of Ca, Na, Sr, and other inorganic elements were highest. The protein content was significantly reduced after calcination. Therefore, these factors cannot accurately reflect the internal quality of TCM, rendering qualitative identification challenging. CaCO3 dissolution in the decoction of Arcae concha and Meretricis concha cyclinae concha increased after calcination, aligning with the clinical application of calcined shell TCM. PCA revealed the inorganic elements in them, indicating that the variation in trace element composition among different drugs leads to differences in their therapeutic focus, which should be considered during usage. CONCLUSIONS: This study clarifies the composition and structure changes of corrugated and clam shell before and after calcining, and it lays the foundation for the comprehensive utilization of marine traditional Chinese medicine. HIGHLIGHTS: These technical representations reveal the differences between raw materials and processed products, which will provide support for the quality control of other shellfish TCM.

Release and health outcomes of exposure to chalk particles in classrooms: a systematic literature review.

This systematic review explores the release and health outcomes of exposure to chalk particles in classrooms. A literature search was conducted on Scopus, Google Scholar, and the Web of Science. Chalk particles contribute significantly to poor indoor air quality in classrooms. Higher concentrations of PM2.5 chalk particles were found in the front row (14.25 µg/m3) and near the chalkboard (19.07 µg/m3). Inhalation and dermal are significant exposure routes; hence, teachers and learners are at risk of developing respiratory and skin disorders. Inhalation of chalk particles correlates with reduced lung function in teachers and learners. The release and size of chalk particles depend on the activities, type of chalk sticks, and texture of the chalkboards. Wiping the chalkboard releases more chalk particles of smaller size (3.85-9.3 µm) than writing (10.57-92.91 µm). A shift from chalk sticks and chalkboards in classrooms is necessary to mitigate the associated health risks.

Molecular and mineral responses of corals grown under artificial Calcite Sea conditions.

The formation of skeletal structures composed of different calcium carbonate polymorphs (e.g. aragonite and calcite) appears to be both biologically and environmentally regulated. Among environmental factors influencing aragonite and calcite precipitation, changes in seawater conditions-primarily in the molar ratio of magnesium and calcium during so-called 'Calcite' (mMg:mCa below 2) or 'Aragonite' seas (mMg:mCa above 2)-have had profound impacts on the distribution and performance of marine calcifiers throughout Earth's history. Nonetheless, the fossil record shows that some species appear to have counteracted such changes and kept their skeleton polymorph unaltered. Here, the aragonitic octocoral Heliopora coerulea and the aragonitic scleractinian Montipora digitata were exposed to Calcite Sea-like mMg:mCa with various levels of magnesium and calcium concentration, and changes in both the mineralogy (i.e. CaCO3 polymorph) and gene expression were monitored. Both species maintained aragonite deposition at lower mMg:mCa ratios, while concurrent calcite presence was only detected in M. digitata. Despite a strong variability between independent experimental replicates for both species, the expression for a set of putative calcification-related genes, including known components of the M. digitata skeleton organic matrix (SkOM), was found to consistently change at lower mMg:mCa. These results support the previously proposed involvements of the SkOM in counteracting decreases in seawater mMg:mCa. Although no consistent expression changes in calcium and magnesium transporters were observed, down-regulation calcium channels in H. coerulea in one experimental replicate and at an mMg:mCa of 2.5, pointing to a possible active calcium uptake regulation by the corals under altered mMg:mCa.

Study on inverse geochemical modeling of hydrochemical characteristics and genesis of groundwater system in coal mine area - a case study of Longwanggou Coal Mine in Ordos Basin.

The exploitation of coal resources has disturbed the equilibrium of the original groundwater system, resulting in a perturbation of the deep groundwater dynamic conditions and hydrochemical properties. Exploring the formation of mine water chemistry under the conditions of deep coal seam mining in the Ordos Basin provides a theoretical basis for the identification of sources of mine water intrusion and the development and utilization of water resources. This paper takes Longwanggou Coal Mine as the research area, collects a total of 106 groups of water samples from the main water-filled aquifers, comprehensively uses Piper trilinear diagram, Gibbs diagram, ion correlation, ion ratio coefficient and mineral saturation index analysis, and carries out inverse geochemical modeling with PHREEQC software, so as to analyze the hydrochemical characteristics and causes of the main water-filled aquifers in deep-buried coal seams in the research area. The results show that the main hydrochemical processes in the study area are leaching and cation exchange, and the groundwater is affected by carbonate (calcite, dolomite), silicate (gypsum) and evaporite. Calculations of mineral saturation indices and PHREEQC simulations have led to the conclusion that the dissolution of rock salt and gypsum in groundwater accounts for most of the ionic action. Na+, Cl- and SO42- are mainly derived from the dissolution of rock salt and gypsum minerals, while Ca2+ and Mg2+ are mostly derived from the dissolution of dolomite and calcite. The results of the inverse geochemical modeling are consistent with the theoretical analysis.

Formation processes of groundwater in a non-ferrous metal mining city of China: Insights from hydrochemical and strontium isotope analyses.

Tongling is a significant non-ferrous metal mining city in China, which produces waste that negatively impacts the area's water environment. It is essential to comprehend the hydrochemical properties and formation processes of groundwater to safeguard and utilize it efficiently. We explored major ions, strontium, and its isotopes in water and river-bottom samples from the northern (i.e., A-A' section) and southern (i.e., B-B' section) areas. The hydrochemical facies show the mining activities have a greater impact on surface water than on groundwater. Groundwater hydrochemical formation results from several factors, with water-rock interaction and ion exchange being primary. Additionally, the dissolution of calcite, dolomite, and feldspar, oxidation of pyrite, and hydrolysis of carbonate minerals also impact the formation of groundwater chemistry. Our analysis of strontium and its isotopes indicates that carbonate dissolution primarily occurred in the recharge area; the runoff from the recharge to the discharge area results in the dissolution of certain silicate rocks; calcite dissolution sources account for > 70% contribution in both surface water and groundwater water-rock interactions, whereas silicate rock dissolution sources and dolomite dissolution sources account for < 30%. Due to changed order of dissolved carbonate and silicate minerals during groundwater flow, the distribution of strontium and its isotopes in the A-A' section is opposite to that in the B-B' section. The findings provide a basis for developing, utilizing, managing, and protecting groundwater resources, especially in similar mining areas.

Identifying sources of acid mine drainage and major hydrogeochemical processes in abandoned mine adits (Southeast Shaanxi, China).

Acid mine drainage (AMD) has resulted in significant risks to both human health and the environment of the Han River watershed. In this study, water and sediment samples from typical mine adits were selected to investigate the hydrogeochemical characteristics and assess the environmental impacts of AMD. The interactions between coexisting chemical factors, geochemical processes in the mine adit, and the causes of AMD formation are discussed based on statistical analysis, mineralogical analysis, and geochemical modeling. The results showed that the hydrochemical types of AMD consisted of SO4-Ca-Mg, SO4-Ca, and SO4-Mg, with low pH and extremely high concentrations of Fe and SO42-. The release behaviors of most heavy metals are controlled by the oxidation of sulfide minerals (mainly pyrite) and the dissolution/precipitation of secondary minerals. Along the AMD pathway in the adit, the species of Fe-hydroxy secondary minerals tend to initially increase and later decrease. The inverse model results indicated that (1) oxidative dissolution of sulfide minerals, (2) interconversion of Fe-hydroxy secondary minerals, (3) precipitation of gypsum, and (4) neutralization by calcite are the main geochemical reactions in the adit, and chlorite might be the major neutralizing mineral of AMD with calcite. Furthermore, there were two sources of AMD in abandoned mine adits: oxidation of pyrite within the adits and infiltration of AMD from the overlying waste rock dumps. The findings can provide deeper insight into hydrogeochemical processes and the formation of AMD contamination produced in abandoned mine adits under similar mining and hydrogeological conditions.

Temporal variations in the surface aragonite saturation state of the Yellow Sea: Observations at the Socheongcho Ocean Research Station during 2017-2022.

Accurately constraining the natural variability of the carbonate system is essential for evaluating long-term changes in coastal areas, which result from the absorption of anthropogenic CO2. This is particularly important given the significant variation in physical and biological processes in these regions. In this regard, the analysis of surface carbonate chemistry in the Yellow Sea was conducted using discrete seawater samples obtained from the Socheongcho Ocean Research Station (37.423°N, 124.738°E) between 2017 and 2022. Our bottle data and sensor pH measurements revealed considerable seasonal variations of aragonite saturation state (ΩAR), typically ranging from 1.6 to 3.9. These variations are particularly pronounced during the summer and early winter. Our dataset serves as a baseline for understanding the long-term changes in ocean acidification in the Yellow Sea, the complex biogeochemical processes in coastal areas, and their impact on ocean acidification.

Azoic sediments and benthic foraminifera: Environmental quality in a subtropical coastal lagoon in the gulf of California.

Marine transitional environments play an important role in human sustainability. Around these ecosystems, coastal lagoons are subject to high anthropogenic pressure from population growth. The increased demand for goods and services is associated with the elevated discharge of untreated and treated wastewater into lagoon systems. The absence of benthic organisms in lagoon environments has been linked to extreme natural conditions and severe anthropogenic impact at both spatial and temporal scales. However, the mechanisms that lead to the presence of azoic sediments in lagoon environments have yet to be studied. This study aimed to determine the vertical variability of textural groups, geochemistry, and benthic foraminiferal fauna to understand how natural and anthropogenic components generate a vertical sediment sequence with low or absent benthic foraminifera in a subtropical coastal lagoon in the southwestern end of the Gulf of California. A 41 cm-long sediment core was collected from La Paz Lagoon at a 1-m depth. The core was sectioned every centimeter, and sediment subsamples were dried and homogenized for grain size, calcium carbonate, elemental and isotopic carbon and nitrogen analyses, and benthic foraminifera quantification. Muds with fine sands towards the core's base characterized the sedimentary sequence. Organic carbon and total nitrogen increased from the base (1.4% and 0.06%, respectively) to the core-top (CT, 3.0% and 0.14%, respectively), significant from the 27 cm interval. Calcium carbonate content was very low (<0.8%). The relationship of δ13C vs. C:N ratio indicated that sedimentary organic carbon was derived from the marine and sewage source mixture. The δ15N of organic matter increased by 3.7‰, starting from the 27 cm interval towards the CT. The nitrogen sewage input source was relatively more significant than nitrogen fixation. The few individuals (<18 ind. in 10 g) and genera (Ammonia and Elphidium), as well as the absence of foraminifera in 19 of 41 intervals in the core, indicated that environmental conditions were unfavorable, even for colonization of environmentally stress-tolerant genera. The frequency of azoic sediments was higher from the 25 cm interval to the CT vs. from the base to the 25 cm interval. Moreover, the AEI revealed severe to moderate hypoxia in the study area. The limited presence of benthic foraminifera and calcium carbonate preservation corroborated that the quality of the lagoon's environment has deteriorated along with population growth, which requires strategic programs to sustain this transitional ecosystem.

Long-term groundwater geochemical evolution induced by coal mining activities-a case study of floor confined limestone aquifer in Yaoqiao Coal Mine, Jiangsu, China.

Groundwater chemical composition can be changed due to long-term coal mining activities, but it was unclear how it was induced in Taiyuan Formation limestone (TFL) regarding the lack of relevant quantitative studies. The aim of this research is to improve understanding of the chemical composition changes in groundwater of L4 limestone in the coal mining area based on the available hydrochemical and hydrodynamical reports and studies during the period 1978-2020. The systematical analysis of the groundwater composition and field allows to make the hydrogeological characterization with the relatively independent blocks by the factor groups "Planar division & Vertical zonation" and "High water pressure, Poor recharge & Little water inflow," which determines different hydrochemical types and high TDS concentration. The long-term groundwater drainage has caused the eastern and southern limestone aquifer to demonstrate a wide range of depression cones and depletion of groundwater resources, the majority areas were dewatered, and the karstification process changed significantly. An analysis of chemical compositions changes due to extensive permanent drainage of L4 limestone water revealed the decrease in the TDS concentration. The solubility of calcite, dolomite, and gypsum changed, which resulted in the decreasing tendency of Ca2+ + Mg2+ ions. Evaporation and concentration were found to be the main factors determining the L4 limestone water composition, whereas ion exchange was the primary factor for rock-water interaction. These findings are helpful for mine enterprises to take necessary measures for preventing and controlling the groundwater quality degradation from the extensive coalmine drainage.

Comparative assessment of soil fertility across varying elevations.

Land elevation exerts a significant influence on soil fertility through affecting macro and micro climatic conditions and geomorphological processes. To evaluate the soil fertility at different elevation classes, namely 1600-2000, 2000-2400, 2400-2800, and > 2800 m, 350 surface soil samples (0-30 cm) were collected from the agricultural lands of northwestern Iran. Soil properties, including soil texture, calcium carbonate (CaCO3), pH, electrical conductivity (EC), organic matter (OM), and soil macronutrients (TN, P, and K) and micronutrients (Fe, Mn, Zn, and Cu), were measured. Finally, the interpretation and classification of the soil samples were made using the nutritional value index (NIV). The comparison of the NIV index based on elevation changes showed that the Gomez method classifies the soil properties in an optimal order as evidenced by its tendency towards the center of the data. However, the Common method is more consistent with the observed trend. After classifying the NIV index using the Common method, it was determined that CaCO3 and soil salinity are not the limiting factor for soil fertility in different elevation classes. However, in all elevations, high pH, low OM at elevations > 2800 m, total nitrogen (TN), available phosphorous (AP), and micronutrients deficiencies, except Zn at the elevation of 1600-2000 m, are the main limiting factors for soil fertility of agricultural lands. The results provide further insight into the elevation-based land evaluation and may supports grower's decision on nutrient management and crop selection strategies.

Geochemical fractionation, bioaccessibility and ecological risk of metallic elements in the weathering profiles of typical skarn-type copper tailings from Tongling, China.

Nonferrous metal tailings have long posed a significant threat to the surrounding environment and population. Previous studies have primarily focused on heavy metal pollution in the vicinity of sulfide tailings, while little attention was given to metal mobility and bioavailability within skarn-type tailings profile during weathering. Therefore, this study aimed to investigate the fractionation, bioaccessibility, and ecological risk associated with metallic elements (MEs, including Pb, Cd, Cr, Zn, and Cu) in two representative weathering copper-tailings profiles of Tongling mine (China). This was achieved through the use of mineralogical analyses, BCR extractions (F1: exchangeable, F2: reducible, F3: oxidizable, F4: residual fraction), in-vitro gastrointestinal simulation test (PBET) and risk assessment models. The mineral compositions of two weathering profiles were similar, with quartz and calcite being the dominant minerals, along with minor amounts of siderite, hematite and spangolite. The mean concentration in the tailings profile was approximately 0.31 (Cr), 1.8 (Pb), 12 (Zn), 33 (Cd) or 34 (Cu) times of the local background values (LBVs). The mean content of the bottom weakly-weathering layer in profile was about 0.36 (Cr), 0.91 (Pb), 1.91 (Cd), 2.73 (Zn) or 2.68 (Cu) times of the surface oxide layer, indicating a strong weathering-leaching effect. The average proportion of BCR-F1 fraction for Cd (30.94 %) was the highest among the five MEs, possibly due to its association with calcite. The PBET-extracted fractions for Cd, Zn and Cu were significantly positively correlated with the F1, F2 and F3 fractions of BCR, suggesting that these elements have higher bioavailability/bioaccessibility. The assessment results indicated that Cd posed a higher health risk, while the risk of Cu, Zn, and Pb is relatively low and Cr is safe. In conclusion, this study provides valuable insights into the environmental geochemical behavior and potential risks of MEs in skarn-type non-ferrous metal tailings ponds.

Pedological data for the study of soils developed over a limestone bed in a humid tropical environment.

Lithological characteristics interact with other factors of soil formation to define soil genesis. This becomes more interesting as data on the mineral and elemental oxide components of soils developed from limestone are rarely available in the humid tropical environment. The present study investigated the elemental oxide content, forms of sesquioxides, and clay mineral species in some limestone soils. Soil samples were obtained from three (3) crestal soil profile pits and analyzed for elemental content by the use of an X-ray fluorescence spectrometer, and sesquioxide forms by inductively coupled plasma-mass spectrometer. Analyses were done in triplicates. The mineralogy of the clay fraction was determined on the A, B, and C horizon samples using an X-ray diffraction technique. The occurrence of SiO2 (203-277 g/kg), Al2O3 (65-105 g/kg), and Fe2O3 (14-95 g/kg) in substantial amounts over MnO2, ZrO2, and TiO2 with negligible quantities of CaO suggested comparatively more developed soils in the Agoi Ibami and Mfamosing tropical rainforests. Crystalline form of Fe was dominant over amorphous form, with indications of the co-migration of dithionite Fe with clay to the B horizons of the soils. Quartz, kaolinite, montmorillonite, and chlorite-vermiculite-montmorillonite interlayered minerals dominated the clay mineralogy of the studied soils. Mineral transformation places the soils at the transitory stage from the intermediate to the complete stage of soil development. The expanding clay minerals are most likely to increase plant nutrient adsorption and soil fertility status to accommodate the cultivation of a wider range of crops.

Assessment of 222Rn, 226Ra, 238U, 218Po, and 214Po activity concentrations in the blood samples of workers at selected building material factories in Erbil City.

The objective of this research is to assess the impact of radon concentration on workers at certain construction material industries in Erbil, Kurdistan Region of Iraq. The CR-39 solid-state track detector was used in this experiment to monitor radon levels and their daughters. For this purpose, as a case study group, 70 workers were divided into seven subgroups (gypsum, cement plant, lightweight block, marble, red brick 1, crusher stone, and concrete block 2), and 20 healthy volunteers were selected as a control group. The findings demonstrate that the mean concentrations of radon, radium, uranium, and radon daughters deposited on the detector face (POS) and chamber walls (POW) for the case study group were 9.61 ± 1.52 Bq/m3, 0.33 ± 0.05 Bq/Kg, 5.39 ± 0.86 mBq/Kg, 4 ± 0.63, and 16.62 ± 2.64 mBq/m3, whereas for the control group, they were 3.39 ± 0.58 Bq/m3, 0.117 ± 0.03 Bq/Kg, 1.91 ± 0.32 mBq/Kg, 1.41 ± 0.24, and 5.88 ± 1 mBq/m3, respectively. The statistical analysis revealed that radon, radium, uranium, and POW and POS concentrations were statistically significant (p ≤ 0.001) in the samples for the case study groups of cement, lightweight block, red brick 1, marble, and crusher stone factories in comparison to the control group; however, the results for gypsum and concrete block 2 factories were not statistically significant in comparison to the control group. Intriguingly, the radon levels in every blood sample examined were far lower than the 200 Bq/m3 limit established by the International Atomic Energy Agency. Hence, it may be argued that the blood is devoid of contaminants. These results are crucial for determining whether or not an individual is exposed to substantial quantities of radiation and for demonstrating a link between radon, its daughter, uranium, and the prevalence of cancer among workers in the Kurdish region of Iraq.

Mineralogy and phase transition mechanisms of atmospheric mineral particles: Migration paths, sources, and volatile organic compounds.

Inorganic mineral particles play an important role in the formation of atmospheric aerosols in the Sichuan Basin. Atmospheric haze formation is accompanied by the phase transition of mineral particles under high humidity and stable climatic conditions. Backward trajectory analysis was used in this study to determine the migration trajectory of atmospheric mineral particles. Furthermore, Positive matrix factorization (PMF) was used to analyze the sources of atmospheric mineral particles. The phase transition mechanisms of atmospheric mineral particles were studied using ion chromatography, inductively coupled plasma emission spectrometry, total organic carbon analysis, X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy coupled with energy dispersive spectrometry, and grand canonical Monte Carlo methods. Three migration and phase transition paths were identified for the mineral particles. Sources of atmospheric mineral particles included combustion, vehicle emissions, industrial emissions, agricultural sources, and mineral dust. The main mineral phases in atmospheric particles, calcite and dolomite, were transformed into gypsum, and muscovite may be transformed into kaolinite. The phase transition of mineral particles seriously affects the formation of aerosols and worsens haze. Typically, along the Nanchong-Suining-Neijiang-Zigong-Yibin path, calcite is converted into gypsum under the influence of man-made inorganic pollution gases, which worsen the haze conditions and cause slight air pollution for 3-5 days. However, along the Guangyuan-Mianyang-Deyang-Chengdu-Meishan-Ya'an path, anthropogenic volatile organic compounds (VOCs) hindered gypsum formation from dolomite. Furthermore, dolomite and VOCs formed stable adsorption systems (system energies from -0.41 to -4.76 eV, long bonds from 0.20 to 0.24 nm). The adsorption system of dolomite and m/p-xylene, with low system energy (-1.46 eV/-1.33 eV) and significant correlation (r2 = 0.991, p < 0.01), was the main cause of haze formation. Consequently, calcite gypsification and dolomite--VOC synergism exacerbated regional haze conditions. This study provides a theoretical reference for the mechanism of aerosol formation in basin climates.

Organic-rich bimineralic ooids record biological processes in Shark Bay, Western Australia.

Marine ooids have formed in microbially colonized environments for billions of years, but the microbial contributions to mineral formation in ooids continue to be debated. Here we provide evidence of these contributions in ooids from Carbla Beach, Shark Bay, Western Australia. Dark 100-240 µm diameter ooids from Carbla Beach contain two different carbonate minerals. These ooids have 50-100 µm-diameter dark nuclei that contain aragonite, amorphous iron sulfide, detrital aluminosilicate grains and organic matter, and 10-20 µm-thick layers of high-Mg calcite that separate nuclei from aragonitic outer cortices. Raman spectroscopy indicates organic enrichments in the nuclei and high-Mg calcite layers. Synchrotron-based microfocused X-ray fluorescence mapping reveals high-Mg calcite layers and the presence of iron sulfides and detrital grains in the peloidal nuclei. Iron sulfide grains within the nuclei indicate past sulfate reduction in the presence of iron. The preservation of organic signals in and around high-Mg calcite layers and the absence of iron sulfide suggest that organics stabilized high-Mg calcite under less sulfidic conditions. Aragonitic cortices that surround the nuclei and Mg-calcite layers do not preserve microporosity, iron sulfide minerals nor organic enrichments, indicating growth under more oxidizing conditions. These morphological, compositional, and mineralogical signals of microbial processes in dark ooids from Shark Bay, Western Australia, record the formation of ooid nuclei and the accretion of magnesium-rich cortical layers in benthic, reducing, microbially colonized areas.

Integration of hydrogeological data, GIS and AHP techniques applied to delineate groundwater potential zones in sandstone, limestone and shales rocks of the Damoh district, (MP) central India.

The Damoh district, which is located in the central India and characterized by limestone, shales, and sandstone compact rock. The district has been facing groundwater development challenges and problems for several decades. To facilitate groundwater management, it is crucial to monitoring and planning based on geology, slope, relief, land use, geomorphology, and the types of the basaltic aquifer in the drought-groundwater deficit area. Moreover, the majority of farmers in the area are heavily dependent on groundwater for their crops. Therefore, delineation of groundwater potential zones (GPZ) is essential, which is defined based on various thematic layers, including geology, geomorphology, slope, aspect, drainage density, lineament density, topographic wetness index (TWI), topographic ruggedness index (TRI), and land use/land cover (LULC). The processing and analysis of this information were carried out using Geographic Information System (GIS) and Analytic Hierarchy Process (AHP) methods. The validity of the results was trained and tested using Receiver Operating Characteristic (ROC) curves, which showed training and testing accuracies of 0.713 and 0.701, respectively. The GPZ map was classified into five classes such as very high, high, moderate, low, and very low. The study revealed that approximately 45% of the area falls under the moderate GPZ, while only 30% of the region is classified as having a high GPZ. The area receives high rainfall but has very high surface runoff due to no proper developed soil and lack of water conservation structures. Every summer season show a declined groundwater level. In this context, results of study area are useful to maintain the groundwater under climate change and summer season. The GPZ map plays an important role in implementing artificial recharge structures (ARS), such as percolation ponds, tube wells, bore wells, cement nala bunds (CNBs), continuous contour trenching (CCTs), and others for development of ground level. This study is significant for developing sustainable groundwater management policies in semi-arid regions, that are experiencing climate change. Proper groundwater potential mapping and watershed development policies can help mitigate the effects of drought, climate change, and water scarcity, while preserving the ecosystem in the Limestone, Shales, and Sandstone compact rock region. The results of this study are essential for farmers, regional planners, policy-makers, climate change experts, and local governments, enabling them to understand the groundwater development possibilities in the study area.