Soluble Minerals Research Articles

Beneficial effects, challenges and opportunities of the filamentous fungus, Aspergillus niger with special reference to the shrimp feed industry—A review

AbstractThe shrimp industry, including its culture and feed sectors, exhibited steady growth over the years with a reduced cost–benefit ratio due to increasing production costs attributed mainly to enhanced feed costs. The unsustainable availability and rapid increase in fishmeal cost have forced the aquafeed sector to reduce dietary inclusion levels. The filamentous fungus, Aspergillus niger plays an important role in utilising plant protein sources for formulating cost‐effective shrimp feed. A. niger has been reported to produce numerous hydrolytic enzymes to degrade the limiting factors of plant proteins such as antinutrients and fibre fractions. This fungus enhanced not only the quantity but also the quality of proteins and amino acids, especially methionine and lysine. Likewise, it also increased the availability of soluble minerals, particularly phosphorous, by degrading the phytic‐phosphorus, thereby helping to replace dietary fishmeal up to 80% in penaeid shrimps. Consequently, this fungus could reduce feed formulation cost significantly. However, the mycotoxins produced by this fungus pose difficulties during large‐scale fermentation, and its implications on the workers and environment cast doubt about its efficacy and utility. However, recent developments indicate that A. niger could be an alternative choice in reducing the pressure on fishmeal demand by enhancing the nutrient utilization of plant‐based materials leading to the formulation of, cost‐effective feeds that can sustain shrimp culture and production in the future.

Boom Clay pore-water geochemistry at the Mol site: Chemical equilibrium constraints on the concentrations of major elements

It is important to understand the mechanisms controlling the chemistry of the pore water in the Boom Clay, which has been studied as a reference host rock for the geological disposal of radioactive waste. The chemistry of the pore water and the related properties of the Boom Clay were investigated experimentally. This paper presents the results of equilibrium calculations and discusses the probable chemical constraints that control the concentrations of major elements in the pore water. The present-day Boom Clay pore water is a dilute NaHCO3 solution of 10–20 mM, and the concentration increases with the depth of the Boom Clay over a thickness of 65 m around the underground laboratory at approximately 200 m below sea level. The present-day NaHCO3 water is likely a result of freshwater infiltration, and the concentration profile observed must have been affected by waters from upper and lower aquifers. Among the minerals found in the Boom Clay, equilibrium calculations indicate that the pore water is in equilibrium with calcite, dolomite, siderite, pyrite, and quartz. Aluminium silicate minerals, kaolinite and chlorite, are also possibly in equilibrium, but their saturation states cannot be fully demonstrated mainly because of uncertainties associated with the pore-water concentration of aluminium. Cation exchange, an important property of clays, seems to be controlling only the pore-water concentration of potassium. Concentrations of other cation exchangeable elements, such as calcium and magnesium, are more likely regulated by the solubility of carbonate minerals. On clay surfaces, however, cation-exchange reactions are evidenced and control occupancies of all exchangeable cations. The cation-exchange pool on clay responds to the increase in NaHCO3 concentration with depth, and the surface occupancies vary according to the selectivity of exchangeable cations. Equilibrium calculations allow us to propose a Boom Clay reference model that is able to explain the observed pore-water chemistry. This model is compared to other models in the literature, such as those for the Opalinus Clay in Switzerland and Callovo-Oxfordian Clay in France, which have also been studied for the purpose of radioactive waste disposal. Future studies to improve our understanding of the Boom Clay pore-water geochemistry include i) accurate determination of the pore-water concentration of aluminium, which is crucial for studying the mineral saturation state of aluminium silicates; ii) improving understanding of the mineralogical composition of dolomite in the Boom Clay and its dissolution mechanisms; iii) reassessment of magnesium cation-exchange occupancy on clay surfaces; and iv) improving pore-water sampling and analysis techniques with respect to pH and pCO2 measurements to avoid perturbations to water samples so that the in situ conditions can be preserved to a maximum extent.

Statistical and isotopic analysis of sources and evolution of groundwater

Investigating sources and evolution of groundwater in the Black Volta River basin is vital for understanding aquifer chemical configuration. Though resettlement has made groundwater in the region an important water supply source, its hydrochemical origin is poorly understood. Therefore, hydrochemistry was coupled with stable isotope (δ2H and δ18O) techniques to improve knowledge for effective groundwater resource management. For this purpose, 23 boreholes were sampled in the Black Volta River basin of Ghana. Major ion dominance is in the order: Na+ > Ca2+ > Mg2+ >K+ and HCO3− > Cl− > SO42− > NO3− respectively. Hydrochemical facies indicates the presence of soluble silicate minerals within aquifer. Hierarchical cluster analysis showed higher ionic concentration within aquifers which decreases towards discharge areas. This is attributed to longer residence time at lower elevations leading to interaction of water with silicate and accessory minerals. Oxygen-18 spatial plot shows recharge occurs along subsurface fractured zones which is confirmed by the water table contour of the study area. Natural geochemical processes, anthropogenic influences and the dissolution of silicate/albite components were extracted using Principal component analysis/factor analysis. These two components which explains the hydrochemistry constituted 79.5% of the total variance in the hydrochemical data and have eigen values > 1. Isotopic composition of groundwater indicates is of meteoric origin and the aquifers were recharged by precipitation. The outcome of this study provides theoretical support for the monitoring and management of groundwater, and its implication on the migration of people in arid/semi-arid regions.

Assessment the ability of water with different ionic strength to dissolve and precipitate carbonate minerals according to omega(Ω) and saturation index (SI)

The study included five locations in Kurdistan Region, Iraq, represented by the soils of Zawita, Zakho, Dukan, Smaquli and Aqrah, in order to know the solubility and precipitation of carbonate minerals based on the values of omega (Ω) and saturation index (SI) using water of different ionic strength (chloride water, sulfur water, Tigris river water).the results showed that the dolomite mineral was more precipitated in term of omega (9.38 * 108) and the saturation index (8.97) in the case of chloride water, while magnesite was soluble where the value of omega was)0.01) and saturation index (-1.85), then when using sulfur water the same behavior appeared for the same mineral (dolomite) in term of precipitation (SI = 9.08) and magnesite in term of solubility (SI = -0.94). The same applies to the water of the Tigris River. As a general conclusion, the dolomite was more precipitated and the magnesite was more soluble in the presence of chloride water compared with the water of the Tigris River and the sulfur water.

Toxic uranium contamination in groundwater of Thoothukudi district, India: Evaluation of health risks using the geochemical and statistical approach

The present investigation aims to determine the health risks of toxic uranium contamination in the drinking water of the Thoothukudi district. Two hundred and eighty-six samples were examined during the pre- and post-monsoon seasons and found the uranium concentration ranges from <0.2 to 167 ppb (mean 12, Standard deviation 21) (pre-monsoon) and <02 to 190 ppb (mean 13, Standard deviation 24) (post-monsoon). Geochemical modeling studies and the reducing nature of samples reveal that the uraninite mineral is under saturated conditions, and the least soluble U4O9 mineral species is predominantly distributed during both seasons. Statistical analysis provides that applying nitrogen and phosphate fertilizers may induce the dissolution of uranium minerals, which is responsible for elevated uranium in the collected samples. The calculated noncarcinogenic risk of uranium range from 0.005 to 8.09 (pre-monsoon) and 0.005 to 9.18 (post-monsoon). 15% (pre-monsoon) and 17% (post-monsoon) of the samples show a higher noncarcinogenic risk. The calculated cancer mortality and morbidity are within the permissible limit of 10−3, and the present health risk assessment of uranium is evident that the people from this district have the chemical toxicity of uranium than the carcinogenic risk due to drinking water.

Effect of boiler feed water composition on inorganic scaling in once-through steam generators estimated using a Monte Carlo modelling approach

Once-through steam generators (OTSGs) produce steam required to recover hydrocarbons from oil sand deposits. OTSGs generate steam at high pressure and temperature, using boiler feed water (BFW) derived from produced water, recycled condensate boiler blowdown (BBD), and small amounts of make-up water sourced from local groundwater. During the OTSG operation cycle, BFW undergoes significant physical and chemical changes, which can cause varying degrees of mineral (scale) precipitation, depending on the BFW quality. Scaling has negative impacts on OTSG performance and has in the past resulted in OTSG tube leaks.In this study, we performed thermodynamic simulations using a Monte Carlo approach with the objective of determining how the composition of the BFW and the steam quality affect scaling. We used 3 different scenarios, characterized by low, intermediate, and high iron-to-BFW ratios to represent various situations of BFW interaction with OTSG pipes. Within each scenario, BFW compositions were randomly assigned within industry-relevant variations of variables including steam quality, pH, and concentrations of SiO2(aq), Mg2+, Ca2+, Fe2+, Cl−, HCO3−, K+, Na+, SO42− and O2 and were allowed to precipitate scales according to thermodynamically controlled solubilities of minerals as they were heated and boiled. Our results show that inorganic scale in OTSGs is composed mostly of aegirine and various Mg and Mg/Ca silicates. We show that the concentrations of dissolved Si, Mg, and Fe available for interaction with BFW are the main factors controlling the mass and mineralogy of scale, whereas the total dissolved solids (TDS) and Ca concentrations within typical chosen operating limits have negligible impact on the scale mass in OTSGs. The modelling results further indicate that efforts to minimize the concentration of Mg in BFW to very low levels (<0.01 mg/kgBFW) show great promise for minimizing inorganic scale formation in OTSGs. Our equilibrium modelling revealed that steam quality has little impact on the total mass of inorganic scale formed in OTSGs because most of the mineral precipitation occurs at temperatures below 250 °C, before boiling starts. However, this finding may not be fully valid if strong kinetic barriers prevent process waters from achieving equilibrium via scale precipitation, especially at lower temperatures. Moreover, because nucleated minerals may be transported through the OTSG without precipitating on the piping walls, increasing steam quality reduces the capacity of BBD to carry over crystallized mineral phases in suspension.

The involvement of organic acids in soil fertility, plant health and environment sustainability.

Increasing demand for safe food by an ever-growing human population emphasizes the urgency for increasing crop yields and reducing the losses caused by abiotic and biotic stresses; a partial solution to this problem is to develop a better understanding of plant-microbe interactions. Plant roots continuously release a wide range of compounds including organic acids in root exudates. These root exudates stimulate growth of specific microbial communities in the rhizosphere, which affect complex biological and physico-chemical interactions occurring between plant roots and the surrounding soil environment. In addition, organic acids are also released by different microbes and during decomposition of organic matter and plant residues in the soil. Interestingly, the available organic acids in the rhizosphere play crucial roles in various physio-chemical processes including the chemoattraction of microbes (both beneficial and pathogenic), mineralization and solubilization of complex minerals (P, K and Zn), biocontrol of phytopathogens, induction of systemic resistance, biogas formation, mitigation of abiotic stresses and, detoxification of metals and residual pesticides. Thus, organic acids play a significant role in the sustainable management of the soil ecosystem and in environmental sustainability. This review discusses the role of organic acids in the stimulation or enrichment of specific root-associated microbial communities and their effect on plant-microbe interactions at the root surface. In addition, the potential for root microbiome modification to enhance nutrient cycling and nutrient acquisition, and in amelioration of environmental stresses for increasing food production is discussed.

Mineral precipitation and hydrochemical evolution through evaporitic processes in soda brines (East African Rift Valley)

Soda lakes of the East African Rift Valley are hyperalkaline, hypersaline lakes extremely enriched in Na+, K+, Cl−, CO32−, HCO3−, and SiO2. In this paper, we investigate the chemical evolution in these lakes and the production of chemical sediments by salt precipitation via evaporation. Water samples from tributary springs and three lakes (Magadi, Nasikie Engida and Natron) have been experimentally studied by in-situ X-ray diffraction during evaporation experiments to characterize the sequence of mineral precipitation. These data are complemented by ex-situ diffraction studies, chemical analyses and thermodynamic hydrochemical calculations producing detailed information on the activity of all solution species and the saturation state of all minerals potentially generated by the given composition. Major minerals precipitating from these samples are sodium carbonates/bicarbonates as well as halite. The CO3/HCO3 ratio, controlled by pH, is the main factor defining the Na‑carbonates precipitation sequence: in lake brines where CO3/HCO3 > 1, trona precipitates first whereas in hot springs, where CO3/HCO3 ≪ 1, nahcolite precipitates instead of trona, which forms later via partial dissolution of nahcolite. Precipitation of nahcolite is possible only at lower pH values (pCO2 higher than −2.7) explaining the distribution of trona and nahcolite in current lakes and the stratigraphic sequences. Later, during evaporation, thermonatrite precipitates, normally at the same time as halite, at a very high pH (>11.2) after significant depletion of HCO3− due to trona precipitation. The precipitation of these soluble minerals increases the pH of the brine and is the main factor contributing to the hyperalkaline and hypersaline character of the lakes. Villiaumite, sylvite, alkaline earth carbonates, fluorapatite and silica are also predicted to precipitate, but most of them have not been observed in evaporation experiments, either because of the small amount of precipitates produced, kinetic effects delaying the nucleation of some phases, or by biologically induced effects in the lake chemistry that are not considered in our calculations. Even in these cases, the chemical composition in the corresponding ions allows for discussion on their accumulation and the eventual precipitation of these phases. The coupling of in-situ and ex-situ experiments and geochemical modelling is key to understanding the hydrogeochemical and hydroclimatic conditions of soda lakes, evaporite settings, and potentially soda oceans of early Earth and other extraterrestrial bodies.

Extraction of Al and rare earth elements via high-pressure leaching of boehmite-kaolinite bauxite using NH4HSO4 and H2SO4

High-silica bauxite is not used to obtain sandy-grade alumina owing to its low alumina/silica ratio (μSi < 3). Acidic methods, such as the use of HCl and NH4HSO4, show promise for treating this raw material. The leaching of boehmite-kaolinite bauxite from the Severoonezhsk deposit mine (Arkhangelsk region, Russia) using a mixture of NH4HSO4 and H2SO4 was investigated for the first time. The bisulfate method, which combines the advantages of the acidic and alkaline methods, involves bauxite leaching, precipitation of ammonium alum, recrystallization for gibbsite precipitation, and calcination for alumina production. The effects of temperature (130–200 °C), liquid-to-solid ratio (8–12), and duration of leaching (5–90 min) on the degrees of extraction of Al, and rare earth elements (REEs) were evaluated. The extractions of Al, Fe, and Ga were found to be >90%, with most of the silica and titania remaining in the residue; moreover, a REEs extraction of 70%–80% was achieved. Residues obtained after leaching were studied by laser diffraction, XRD, XRF, and SEM to elucidate the leaching mechanism and the solubility of Al-containing minerals, such as boehmite (AlOOH), kaolinite (Al4[Si4O10](OH)8), and muscovite (KAl2[AlSi3O10](OH)2). The acquired data can be used to facilitate the development of an effective technology for the treatment of high-silica bauxite in Russia.

Synergistic Enhancement of Lead and Selenate Uptake at the Barite (001)-Water Interface.

The interactions of heavy metals with minerals influence the mobility and bioavailability of toxic elements in natural aqueous environments. The sorption of heavy metals on covalently bonded minerals is generally well described by surface complexation models (SCMs). However, understanding sorption on sparingly soluble minerals is challenging because of the dynamically evolving chemistry of sorbent surfaces. The interpretation can be even more complicated when multiple metal ions compete for sorption. In the present study, we observed synergistically enhanced uptake of lead and selenate on the barite (001) surface through two sorption mechanisms: lattice incorporation that dominates at lower coverages and two-dimensional monolayer growth that dominates at higher coverages. We also observed a systematic increase in the sorption affinity with increasing co-sorbed ion coverages, different from the assumption of invariant binding constants for individual adsorption processes in classical SCMs. Computational simulations showed thermodynamically favorable co-incorporation of lead and selenate by simultaneously substituting for barium and sulfate in neighboring sites, resulting in the formation of molecular clusters that locally match the net dimension of the substrate lattice. These results emphasize the importance of ion-ion interactions at mineral-water interfaces that control the fate and transport of contaminants in the environment.

Characteristics and Controlling Factors of Groundwater Hydrochemistry in Dongzhi Tableland Area of the Loess Plateau of Eastern Gansu—A Case Study of Ning County Area, North China

Groundwater plays an irreplaceable role in all aspects of the Loess Plateau. In this study, the loess phreatic water (LPW) and bedrock phreatic water (BPW) in the Ning County area (NCA) were sampled and analyzed, and the characteristics and controlling factors of groundwater were determined by using statistical analysis, hydrochemical methods, and hydrogeochemical simulation. The results indicated that the groundwater in the NCA was alkaline as a whole, and the average pH values of LPW and BPW were 8.1 and 7.8, respectively. The mean values of TDS concentrations of LPW and BPW were 314.9 mg/L and 675.3 mg/L, and the mean values of TH contents were 194.6 mg/L and 286.6 mg/L, respectively, which were mainly divided into hard fresh water. The Piper diagram illustrated that the hydrochemical type of groundwater in the NCA was mainly the HCO3·Ca type. The main recharge source of groundwater was atmospheric precipitation, and it was affected by evaporation to a certain extent. The linear relationships of δ18O and δ2H of LPW and BPW were δ2H = 6.998δ18O − 3.802 (R2 = 0.98) and δ2H = 6.283δ18O − 10.536 (R2 = 0.96), respectively. Hydrochemical analysis indicated that the groundwater in the NCA was mainly controlled by rock weathering and cation exchange. BPW was affected by the dissolution of gypsum. The possible mineral phases were identified on the basis of the main soluble minerals in the aquifer, and hydrogeochemical reverse simulations were performed. The dissolution of calcite, illite, and hornblende, and the precipitation of dolomite, plagioclase, and microcline occurred on both the LPW and BPW pathways.

Functional Interpretation of Cross-Talking Pathways with Emphasis on Amino Acid Metabolism in Rhizosphere Microbiome of the Wild Plant Moringa oleifera

The functional processes and mutual benefits of the wild plant Moringa oleifera and its rhizosphere microbiome were studied via metagenomic whole-genome shotgun sequencing (mWGS) in comparison with a bulk soil microbiome. The results indicated high gene abundance of the four KEGG categories, “Cellular Processes”, “Environmental Information Processing”, “Genetic Information Processing”, and “Metabolism”, in the rhizosphere microbiome. Most of the enriched enzymes in rhizobacteria are assigned to the pathway “Amino acids metabolism”, where soil-dwelling microbes use amino acids as a defense mechanism against phytopathogens, while promoting growth, colonizing the cohabiting commensal microbes and conferring tolerance against abiotic stresses. In the present study, it was proven that these beneficial microbes include Bacillus subtilis, Pseudomonas fluorescens, and Escherichia coli. Mineral solubilization in these rhizobacteria can make nutrients available for plant utilization. These rhizobacteria extensively synthesize and metabolize amino acids at a high rate, which makes nitrogen available in different forms for plants and microbes. Amino acids in the rhizosphere might stand mainly as an intermediate switcher for the direction of the soil nitrogen cycle. Indole acetic acid (IAA) was proven to be synthesized by these beneficial rhizobacteria via route indole-3-pyruvate (IPyA) of the pathway “Tryptophan metabolism”. This hormone might stand as a shuttle signaling molecule between M. oleifera and its rhizobacteria. Tryptophan is also metabolized to promote other processes with important industrial applications. Rhizobacteria were also proven to breakdown starch and sucrose into glucose, which is the primary metabolic fuel of living organisms. In conclusion, we assume that the metabolic processes in the rhizosphere microbiome of this wild plant can be eventually utilized in boosting the sustainability of agriculture applications and the plant’s ability to benefit from soil nutrients when they are not in the form available for plant root absorption.

Perbedaan Kelarutan Kalsium Gigi Sulung Setelah Direndam dalam Jus Lemon (Citrus limon) dan Yogurt

Tooth erosion is common problem and its prevalence is increasing in children. Children's penchant for consuming packaged drinks that have high acid content triggers tooth erosion. Tooth erosion is characterized by mineral solubility on the tooth surface due to consuming acidic foods and drinks continuously for a long time. The purpose of this study was to determine the difference in the calcium solubility of primary teeth after immersing in lemon juice (Citrus limon) and yogurt. This research method is experimental laboratory with post-test control group design using twenty-seven mandibular primary incisors which were divided into two groups (control and treatment). The treatment group was divided into six sub-groups, immersing in lemon juice for 6 hours, 12 hours, 18 hours and yogurt for 6 hours, 12 hours, 18 hours, while the control group was divided into three subgroups, immersing in artificial saliva. 6 hours, 12 hours and 18 hours. Testing the calcium solubility using an Atomic Absorption Spectrophotometer (AAS) then the differences between groups were analyzed using one way ANOVA. The results showed a significant difference, the solubility of calcium after immersing in lemon juice for 18 hours was 66.76 ppm and the solubility of calcium after immersing in yogurt for 18 hours was 22.07 ppm. So, it can be concluded that the calcium solubility in primary teeth after immersing in lemon juice is greater than yogurt.

Characterization of pulp calcifications and changes in their composition after treatments with citric acid and ethylenediaminetetraacetic acid solutions.

The ectopic calcifications of non-mineralized tissues can occur in several forms throughout life, such as pulpal calcification. The presence of pulp stones is a challenge in endodontic treatment because they partially or fully obliterate the pulp chamber hindering access to root canals and their subsequent shaping. This study aimed to determine their crystallographic properties and evaluate the capacity of citric acid (CA) and ethylenediaminetetraacetic acid (EDTA) to promote the demineralization of pulp calcifications. The samples were obtained from patients with indications of endodontic treatment, and the radiographic examination was suggestive of pulp stone in at least one permanent tooth. The samples were isolated and analyzed by scanning electron microscopy/energy-dispersive x-ray spectroscopy (SEM/EDX). The Fourier Transform by high resolution-transmission electron microscopy, Raman microscopy, and X-ray diffraction (XRD) were used to identify the mineral phase and crystallographic characteristics. To evaluate the effect of CA and EDTA on the crystallinity of calcifications, they were submerged into these two individual solutions and the changes were assessed in situ by Raman spectroscopy. The SEM images obtained from calcifications demonstrated irregular morphologies. EDX of sample surfaces shows a high presence of oxygen, carbon, calcium, and phosphorous, however, other elements such as sodium, magnesium, nitrogen, chlorine, potassium, sulfur, and zinc were identified in less quantity. According to Raman, XRD, and high-resolution transmission electron microscopy, the predominant mineral phase identified in the pulpal calcification was a poor crystallinity apatite. According to in situ analyses, the effect of CA and EDTA was observed on the signals of PO4 3- and CH2 groups corresponding to inorganic and organic components. The changes with CA were evident at 7min while the effect of EDTA was observed until 15 min of treatment. All results indicate that pulp stones have a heterogeneous composition principally composed of apatite with low crystallinity. The solubility of these pathological minerals is adequate using solutions such as EDTA or CA; however, the effectivity depends on the mineralization grade of calcifications, time, and concentration of exposition to this chemical.

TRAKYA YÖRESİ BALLARININ MİNERAL İÇERİĞİ VE BAZI TİPİK KALİTE PARAMETRELERİ AÇISINDAN DEĞERLENDİRİLMESİ

Çalışmanın amacı, Trakya bölgesi çiçek ve salgı ballarının mineral içeriği ve bazı kalite parametrelerinin belirlenmesidir. Bu amaçla Trakya Bölgesi'nde yerel olarak üretilen 16 adet ayçiçeği, 2 adet karaçalı, 3 adet kanola, 3 adet meşe ve 1 adet ıhlamur balı olmak üzere toplam 25 adet bal örneğinde 8 farklı mineral (Ca, Fe, K, Mg, Na, Zn, P, Se) düzeyi ve bazı tipik kalite parametreleri (çözünür kuru madde, pH, elektriksel iletkenlik, serbest asitlik, HMF ve şeker içeriği) analiz edilmiştir. Bal örneklerinin mineral içerikleri İndüktif Eşleşmiş Plazma Optik Emisyon Spektrometresi (ICP-OES) ile analiz edilmiştir. Ballarda en çok bulunan mineraller sırasıyla potasyum, fosfor ve kalsiyum olup 18.91–1018.74, 244.40–429.98 ve 8.50–140.82 mg/kg arasında belirlenmiştir. Kalite parametreleri ortalama olarak pH 4.42 (3.86-6.54), çözünür kuru madde 81.4°Bx (79.3-83.0), serbest asitlik 15.66 mEq/kg (9.00-28.00), HMF 13.00 mg/kg (0.16-33.45), elektriksel iletkenlik 595 μS/cm (207-1376), glukoz %33.66 (25.51-38.58), fruktoz %38.17 (33.32-47.91), sakkaroz %0.17 (0.01-0.67) olarak tespit edilmiştir.

Complete Crystal Structures and Elastic Properties of the Uranyl Minerals Johannite, Pseudojohannite and Derriksite

Due to the high solubility of uranyl sulfate and selenite minerals, the investigation involving the determination of the crystal structures and physical properties of these minerals is essential in actinide environmental chemistry for the simulation of uranium migration from uraninite deposits and nuclear waste repositories. However, the determination of the complete crystal structures of the uranyl sulfate minerals johannite (Cu(UO2)2(SO4)2(OH)2 ·8H2O) and pseudojohannite (Cu3(UO2)4(SO4)2O4(OH)2 ·12H2O) and the uranyl selenite mineral derriksite (Cu4[((UO2)(SeO3)2(OH)6]) has not been feasible so far. In this work, the crystal structures of these minerals, including the positions of the hydrogen atoms, are determined using first principles solid-state methods based on periodic density functional theory using plane wave basis sets and pseudopotentials. The lattice parameters and associated geometrical variables as well as the corresponding X-ray diffraction patterns derived from the computed crystal structures are in excellent agreement with their experimental counterparts, derived from the corresponding experimental structures lacking the hydrogen atom positions. The complete crystal structure of derriksite is also determined by refinement from X-ray diffraction data, the resulting structure being consistent with the computed one. The knowledge of the positions of H atoms is of fundamental importance not only because they define the corresponding hydrogen bond networks holding together the atoms in the structures, but also because it allows for the efficient, inexpensive and safe determination of the physical properties using first principles methods. This feature is particularly important in the case of uranium-containing minerals due to their radiotoxicity, complicating the handling of the samples and experimental measurements. In this work, from the computed crystal structures, the elasticity tensors of these minerals are computed using the finite displacement method and a rich set of elastic properties including the bulk, Young’s and shear moduli, the Poisson’s ratio, ductility, anisotropy and hardness indices and bulk modulus derivatives with respect to pressure derivatives are determined.

Evolution of groundwater salinity and fluoride in the deep confined aquifers of Cangzhou in the North China plain after the South-to-North Water Diversion Project

The South-to-North Water Diversion Project (SNWDP) has greatly improved the water shortage in the North China Plain. However, the impact of the SNWDP on the evolution of groundwater chemistry, especially fluoride and salinity, was still unknown. Cangzhou, one of the recipient cities of SNWDP and suffered from severe land subsidence, was selected to collect the deep confined groundwater samples before and after the SNWDP. The results showed that groundwater fluoride concentration decreased after the SNWDP, with a median value of 4.39 mg/L in 2017 and 3.00 mg/L in 2021, respectively. This trend was more clearly observed in the land subsidence area, which could be related to the reduction of land subsidence, due to the stopping pumping of deep groundwater. The pore water in clayey sediments contains fluoride up to 7.02 mg/L, which can be released into groundwater due to the sediment compaction before the SNWDP. The extensive exploitation during last decades changed the groundwater recharge patterns, resulting in over 60% deep groundwater being recharged by the pore water released from clayey sediment. The results of the Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) suggested that land subsidence has slowed down after the SNWDP, especially in the central area of land subsidence, thereby restricting the release of fluoride-rich pore water. However, groundwater salinity increased after the SNWDP, and the number of samples exceeding the drinking standard (TDS <1000 mg/L) increased by 26.4%. The rising groundwater level favors the water-rock interaction, promoting the dissolution of soluble minerals, for instance, halite, which was reflected by the results of inverse and forward modeling using the PHREEQC. Groundwater salinization after the SNWDP potentially induces the fluorite dissolution and causes the elevation of groundwater fluoride concentration. However, the calculated results indicate that the amount of F elevation related to groundwater salinization is significantly lower than the contribution of fluoride-rich pore water from clay sediment compaction. The findings of this study provide a comprehensive assessment of the influence of the SNWDP on the groundwater quality and some new insights for the management of groundwater resources.

Plant Growth-Promoting Bacteria (PGPB) integrated phytotechnology: A sustainable approach for remediation of marginal lands.

Land that has little to no utility for agriculture or industry is considered marginal land. This kind of terrain is frequently found on the edge of deserts or other arid regions. The amount of land that can be used for agriculture continues to be constrained by increasing desertification, which is being caused by climate change and the deterioration of agriculturally marginal areas. Plants and associated microorganisms are used to remediate and enhance the soil quality of marginal land. They represent a low-cost and usually long-term solution for restoring soil fertility. Among various phytoremediation processes (viz., phytodegradation, phytoextraction, phytostabilization, phytovolatilization, phytofiltration, phytostimulation, and phytodesalination), the employment of a specific mechanism is determined by the state of the soil, the presence and concentration of contaminants, and the plant species involved. This review focuses on the key economically important plants used for phytoremediation, as well as the challenges to plant growth and phytoremediation capability with emphasis on the advantages and limits of plant growth in marginal land soil. Plant growth-promoting bacteria (PGPB) boost plant development and promote soil bioremediation by secreting a variety of metabolites and hormones, through nitrogen fixation, and by increasing other nutrients' bioavailability through mineral solubilization. This review also emphasizes the role of PGPB under different abiotic stresses, including heavy-metal-contaminated land, high salinity environments, and organic contaminants. In our opinion, the improved soil fertility of marginal lands using PGPB with economically significant plants (e.g., Miscanthus) in dual precession technology will result in the reclamation of general agriculture as well as the restoration of native vegetation.

Fruit collapse incidence and quality of pineapple as affected by biopesticides based on Pseudomonas fluorescens and Trichoderma harzianum

In this study the effect of Pseudomonas fluorescens and Trichoderma harzianum based biopesticides on fruit collapse disease incidence and pineapple quality was investigated. The experiment was implemented in a split-plot design with two factors, one involving two inoculation methods (spray and inject), and a second factor involving four treatments, A (control: no biopesticides used), B (Bio P32 from 13 weeks before harvest), C (Bio T10 from 13 weeks before harvest) and D (Bio P32 + Bio T10 from 13 weeks before harvest). The inoculated pathogen was Dickeya zeae. The incidence of fruit collapse, total soluble solids, total acidity, sucrose, ascorbic acid, mineral content, and electrolyte leakage were determined. The inject method caused more fruit collapse incidence than the spray method. Treatments C and D provided the best results having a low incidence of fruit collapse (spray: 5 and 1.7 %, inject: 20 % in both cases), high antioxidant capacity (regarding ascorbic acid), high mineral nutrient content (in terms of Ca and Mg), and low electrolyte leakage content (&lt; 70 % in average), with a healthier cell wall characteristic. Meanwhile, treatments A and B were less efficient in these aspects and promoted the incidence of fruit collapse, especially when the inject method was used, as this was more harmful regarding the fruit physiology. In conclusion, the biopesticides employed can reduce the incidence of fruit collapse and positively affect the fruit quality.

Characterization of Agro-Livestock Wastes for Composting in Rural Zones in Ecuador: The Case of the Parish of San Andrés

In Ecuador, the agriculture and livestock sectors are very important within the economy of rural areas. These activities generate a large amount of waste whose management is not optimized. Thus, the aim of this work was to characterize different agro-livestock wastes generated in a rural area, the parish of San Andrés (Chimborazo-Ecuador), in order to know their composition to design suitable composting processes for their treatment. To this end, different physicochemical and chemical parameters were determined in 24 crop residue samples and 18 manure samples, and two piles were elaborated with the same proportion of wastes (51% vegetable residue + 35% cow manure + 14% sawdust) and composted by turning or passive aeration. Throughout the composting process, the temperature and oxygen concentration were recorded and the evolution of different physicochemical, chemical, and biological parameters and the quality of the final composts were studied. The results indicated that the agro-livestock residues presented notable macro and micronutrient and organic matter contents and low levels of heavy metals, these properties being positive for their subsequent treatment in a co-composting experiment. This experiment demonstrated that the composting processes are a feasible strategy for the treatment of these residues and yield compost with an adequate agricultural quality (notable nitrogen content, low heavy metal and soluble mineral salt contents and 92–94% in germination index). Moreover, the passive aeration system can be recommended because this aeration method reduced composting times and the work associated with the process. However, more studies are required on this composting system and other agro-livestock wastes to establish a management protocol for all the waste generated, which will contribute to the sustainability of the agro-livestock sector in the area studied.