scholarly journals Presence and Distribution of Fluoride Ions in Groundwater for Human in a Semiconfined Volcanic Aquifer

Resources ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 116 ◽  
Author(s):  
Cecilia Judith Valdez-Alegría ◽  
Rosa María Fuentes-Rivas ◽  
José Luis García-Rivas ◽  
Reyna María Guadalupe Fonseca-Montes de Oca ◽  
Beatriz García-Gaitán
Keyword(s):  
Chloride Ions ◽  
Anthropogenic Activity ◽  
Fluoride Ions ◽  
Rock Interaction ◽  
Bicarbonate Ions ◽  
High Concentrations ◽  
Toluca Valley ◽  
Meteoric Precipitation ◽  
Mexico Basin

Dental and emaciated fluorosis is derived from the chronic intake of fluoride ions (F−) by consumption of food, tooth products and drinking water from groundwater. Recent reports indicate that in some regions of Mexico, the incidence of fluorosis in temporary and permanent dentitions have increased in recent years. The purpose of the present investigation was to determine the presence and distribution of F− ions in semi-confined aquifers, located in the basins of Lerma-Chapala and Valley of México. Temperature (T), pH, electrical conductivity (EC) and alkalinity were determined in situ, in 27 groundwater wells. The hardness, chloride ions (Cl−), free chlorine (Cl2), total dissolved solids (TDS) and bicarbonates (HCO3−), were determined in the laboratory. The high content of bicarbonate ions (HCO3−) is associated with the alteration of silicates and the presence of chloride ions (Cl−) due to the anthropogenic activity. The highest value of fluoride ions (F−) (1.31 mg/L) was identified in a well of the Lerma-Chapala basin and in 25% of the samples (1.056 mg/L) of the Valley of México basin. The groundwater in the Lerma-Chapala basin is of the Ca-HCO3 type and the water in the Valley of Mexico basin is Na-HCO3 and Ca-HCO3. According to the Gibbs diagram, the water of the Toluca Valley aquifer is recharged by local meteoric precipitation and consequent the water-rock interaction occurs. The correlation analysis shows the significant relationship between F− and CE (R = 0.5933), F− and alkalinity (R = 0.6924), F− and HCO3− (R = 0.6924) and F− and TDS (R = 0.5933). The correlations confirm that the content of fluoride ions present in groundwater is associated with high concentrations of bicarbonate ions and the presence of sodium, due to a process of alteration of the silicates.

New Technologies for Decontamination of Radioactive Substances Scattered by Nuclear Accident / Nowe Technologie Dekontaminacji Radioaktywnych Substancji Rozproszonych Przez Awarie Nuklearna

2013 ◽  
Vol 58 (1) ◽  
pp. 283-290 ◽  
Author(s):  
Y. Nishizaki ◽  
H. Miyamae ◽  
S. Ichikawa ◽  
K. Izumiya ◽  
T. Takano ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
New Technologies ◽  
Ferric Hydroxide ◽  
Nuclear Accident ◽  
Radioactive Cesium ◽  
Cesium Ions ◽  
Naoh Solution ◽  
High Concentrations ◽  
Water Rinsing

Our effort for decontamination of radioactive cesium scattered widely by nuclear accident in March 2011 in Fukushima, Japan has been described. Radioactive cesium scattered widely in Japan has been accumulating in arc or plasma molten-solidified ash in waste incinerating facilities up to 90,000 Bq/kg of the radioactive waste. Water rinsing of the ash resulted in dissolution of cesium ions together with high concentrations of potassium and sodium ions. Although potassium inhibits the adsorption of cesium on zeolite, we succeeded to precipitate cesium by in-situ formation of ferric ferrocyanide and iron rust in the radioactive filtrate after rinsing of the radioactive ash with water. Because the regulation of no preservation of any kind of cyanide substances, cesium was separated from the precipitate consisting of cesium-captured ferric ferrocyanide and ferric hydroxide in diluted NaOH solution and subsequent filtration gave rise to the potassium-free radioactive filtrate. Cesium was captured by zeolite from the potassium-free radioactive filtrate. The amount of this final radioactive waste of zeolite was significantly lower than that of the arc-molten-solidified ash.

scholarly journals An Autonomous Platform for Near Real-Time Surveillance of Harmful Algae and Their Toxins in Dynamic Coastal Shelf Environments

2021 ◽  
Vol 9 (3) ◽  
pp. 336
Author(s):  
Stephanie K. Moore ◽  
John B. Mickett ◽  
Gregory J. Doucette ◽  
Nicolaus G. Adams ◽  
Christina M. Mikulski ◽  
...  
Keyword(s):  
Real Time ◽  
Domoic Acid ◽  
Harmful Algae ◽  
Coastal Trapped Waves ◽  
Resource Managers ◽  
Bloom Formation ◽  
High Concentrations ◽  
Data Gap ◽  
Autonomous Technology

Efforts to identify in situ the mechanisms underpinning the response of harmful algae to climate change demand frequent observations in dynamic and often difficult to access marine and freshwater environments. Increasingly, resource managers and researchers are looking to fill this data gap using unmanned systems. In this study we integrated the Environmental Sample Processor (ESP) into an autonomous platform to provide near real-time surveillance of harmful algae and the toxin domoic acid on the Washington State continental shelf over a three-year period (2016–2018). The ESP mooring design accommodated the necessary subsystems to sustain ESP operations, supporting deployment durations of up to 7.5 weeks. The combination of ESP observations and a suite of contextual measurements from the ESP mooring and a nearby surface buoy permitted an investigation into toxic Pseudo-nitzschia spp. bloom dynamics. Preliminary findings suggest a connection between bloom formation and nutrient availability that is modulated by wind-forced coastal-trapped waves. In addition, high concentrations of Pseudo-nitzschia spp. and elevated levels of domoic acid observed at the ESP mooring location were not necessarily associated with the advection of water from known bloom initiation sites. Such insights, made possible by this autonomous technology, enable the formulation of testable hypotheses on climate-driven changes in HAB dynamics that can be investigated during future deployments.

scholarly journals Fe3O4@C Nanoparticles Synthesized by In Situ Solid-Phase Method for Removal of Methylene Blue

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 330
Author(s):  
Hengli Xiang ◽  
Genkuan Ren ◽  
Yanjun Zhong ◽  
Dehua Xu ◽  
Zhiye Zhang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Solid Phase ◽  
Raw Materials ◽  
Phase Method ◽  
Maximum Adsorption Capacity ◽  
High Catalytic Activity ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
High Concentrations

Fe3O4@C nanoparticles were prepared by an in situ, solid-phase reaction, without any precursor, using FeSO4, FeS2, and PVP K30 as raw materials. The nanoparticles were utilized to decolorize high concentrations methylene blue (MB). The results indicated that the maximum adsorption capacity of the Fe3O4@C nanoparticles was 18.52 mg/g, and that the adsorption process was exothermic. Additionally, by employing H2O2 as the initiator of a Fenton-like reaction, the removal efficiency of 100 mg/L MB reached ~99% with Fe3O4@C nanoparticles, while that of MB was only ~34% using pure Fe3O4 nanoparticles. The mechanism of H2O2 activated on the Fe3O4@C nanoparticles and the possible degradation pathways of MB are discussed. The Fe3O4@C nanoparticles retained high catalytic activity after five usage cycles. This work describes a facile method for producing Fe3O4@C nanoparticles with excellent catalytic reactivity, and therefore, represents a promising approach for the industrial production of Fe3O4@C nanoparticles for the treatment of high concentrations of dyes in wastewater.

Effects of hydrogen peroxide and hypochlorite on membrane potential of mitochondria in situ in rat heart cells

1991 ◽  
Vol 69 (11) ◽  
pp. 1705-1712 ◽  
Author(s):  
Noburu Konno ◽  
K. J. Kako
Keyword(s):  
Hydrogen Peroxide ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Rat Heart ◽  
Mitochondrial Membrane ◽  
Isolated Rat Heart ◽  
Heart Mitochondria ◽  
High Concentrations ◽  
Isolated Rat

Hydrogen peroxide (H2O2) and hypochlorite (HOCl) cause a variety of cellular dysfunctions. In this study we examined the effects of these agents on the electrical potential gradient across the inner membrane of mitochondria in situ in isolated rat heart myocytes. Myocytes were prepared by collagenase digestion and incubated in the presence of H2O2 or HOCl. Transmembrane electrical gradients were measured by distribution of [3H]triphenylmethylphosphonium+, a lipophilic cation. The particulate fraction was separated from the cytosolic compartment first by permeabilization using digitonin, followed by rapid centrifugal sedimentation through a bromododecane layer. We found that the mitochondrial membrane potential (161 ± 7 mV, negative inside) was relatively well maintained under oxidant stress, i.e., the potential was decreased only at high concentrations of HOCl and H2O2 and gradually with time. The membrane potential of isolated rat heart mitochondria was affected similarly by H2O2 and HOCl in a concentration- and time-dependent manner. High concentrations of oxidants also reduced the cellular ATP level but did not significantly change the matrix volume. When the extra-mitochondrial free calcium concentration was increased in permeabilized myocytes, the transmembrane potential was decreased proportionally, and this decrease was potentiated further by H2O2. These results support the view that heart mitochondria are equipped with well-developed defense mechanisms against oxidants, but the action of H2O2 on the transmembrane electrical gradient is exacerbated by an increase in cytosolic calcium. Keywords: ATP, calcium, cardiomyocyte, cell defense, mitochondrial membrane potential, oxidant, triphenylmethylphosphonium.

Magmatic-Hydrothermal Mineralization Processes at the Yidong Tin Deposit, South China: Insights from In Situ Chemical and Boron Isotope Changes of Tourmaline

2021 ◽  
Author(s):  
He-Dong Zhao ◽  
Kui-Dong Zhao ◽  
Martin R. Palmer ◽  
Shao-Yong Jiang ◽  
Wei Chen
Keyword(s):  
South China ◽  
Hydrothermal Fluids ◽  
Boron Isotope ◽  
Granitic Magma ◽  
Gangue Mineral ◽  
Rock Interaction ◽  
Hydrothermal Mineralization ◽  
Mineralization Processes ◽  
Tin Deposit

Abstract Owing to the superimposition of water-rock interaction and external fluids, magmatic source signatures of ore-forming fluids for vein-type tin deposits are commonly overprinted. Hence, there is uncertainty regarding the involvement of magmatic fluids in mineralization processes within these deposits. Tourmaline is a common gangue mineral in Sn deposits and can crystallize from both the magmas and the hydrothermal fluids. We have therefore undertaken an in situ major, trace element, and B isotope study of tourmaline from the Yidong Sn deposit in South China to study the transition from late magmatic to hydrothermal mineralization. Six tourmaline types were identified: (1) early tourmaline (Tur-OE) and (2) late tourmaline (Tur-OL) in tourmaline-quartz orbicules from the Pingying granite, (3) early tourmaline (Tur-DE) and (4) late tourmaline (Tur-DL) in tourmaline-quartz dikelets in the granite, and (5 and 6) core (Tur-OC) and rim (Tur-OR), respectively of hydrothermal tourmaline from the Sn ores. Most of the tourmaline types belong to the alkali group and the schorl-dravite solid-solution series, but the different generations of magmatic and hydrothermal tourmaline are geochemically distinct. Key differences include the hundredfold enrichment of Sn in hydrothermal tourmaline compared to magmatic tourmaline, which indicates that hydrothermal fluids exsolving from the magma were highly enriched in Sn. Tourmaline from the Sn ores is enriched in Fe3+ compared to the hydrothermal tourmaline from the granite and displays trends of decreasing Al and increasing Fe content from core to rim, relating to the exchange vector Fe3+Al–1. This reflects oxidation of fluids during the interaction between hydrothermal fluids and the mafic-ultramafic wall rocks, which led to precipitation of cassiterite. The hydrothermal tourmaline has slightly higher δ11B values than the magmatic tourmaline (which reflects the metasedimentary source for the granite), but overall, the tourmaline from the ores has δ11B values similar to those from the granite, implying a magmatic origin for the ore-forming fluids. We identify five stages in the magmatic-hydrothermal evolution of the system that led to formation of the Sn ores in the Yidong deposit based on chemical and boron isotope changes of tourmaline: (1) emplacement of a B-rich, S-type granitic magma, (2) separation of an immiscible B-rich melt, (3) exsolution of an Sn-rich, reduced hydrothermal fluid, (4) migration of fluid into the country rocks, and (5) acid-consuming reactions with the surrounding mafic-ultramafic rocks and oxidation of the fluid, leading to cassiterite precipitation.

Developing an in situ, hydromechanical coupling, true triaxial rock compression tester and investigating the deformation patterns of reservoir bank slopes

2021 ◽  
pp. qjegh2021-043
Author(s):  
Lei Fan ◽  
Meiwan Yu ◽  
Aiqing Wu ◽  
Yihu Zhang
Keyword(s):  
Coupling Effect ◽  
Water Pressure ◽  
Pressure Coefficient ◽  
Hydromechanical Coupling ◽  
Rock Interaction ◽  
True Triaxial ◽  
Rock Structure ◽  
Deformation Patterns

Interactions between water and rocks are the main factors affecting the deformation of rock masses on sloped banks by reservoir impoundment. The technology used in laboratory tests of water-rock interaction mechanisms cannot simulate the coupling of water, the rock structure and the initial stress environment. In this work, we develop an in situ hydromechanical true triaxial rock compression tester and apply it to investigate the coupling response of reservoir bank rocks to changing groundwater levels. The tester is composed of a sealed chamber, loader, reactor, and device for measuring deformation, which are all capable of withstanding high water pressures, and a high-precision servo controller. The maximum axial load, lateral load and water pressure are 12 000 kN, 3 000 kN and 3 MPa, respectively. The dimensions of the test specimens are 310 mm×310 mm×620 mm. The test specimens are grey-black basalts with well-developed cracks from the Xiluodu reservoir area. The results show that increasing water pressure promotes axial compression and lateral expansion, while decreasing water pressure causes axial expansion and lateral compression. A water pressure coefficient, K, is introduced as a measure of the hydromechanical coupling effect (expansion or compression) with changing groundwater level. A mechanical tester can be used to perform accurate field tests of the response of wet rocks to hydromechanical coupling. The test results provide new information about the deformation patterns of rock slopes in areas surrounding high dams and reservoirs.Thematic collection: This article is part of the Role of water in destabilizing slopes collection available at: https://www.lyellcollection.org/cc/Role-of-water-in-destabilizing-slopes

scholarly journals The aerosol-climate model ECHAM5-HAM

2005 ◽  
Vol 5 (4) ◽  
pp. 1125-1156 ◽  
Author(s):  
P. Stier ◽  
J. Feichter ◽  
S. Kinne ◽  
S. Kloster ◽  
E. Vignati ◽  
...  
Keyword(s):  
Size Distribution ◽  
Climate Model ◽  
Normal Modes ◽  
Anthropogenic Activity ◽  
Climate Modelling ◽  
Extensive Evaluation ◽  
Wide Range ◽  
Log Normal ◽  
Year 2000

Abstract. The aerosol-climate modelling system ECHAM5-HAM is introduced. It is based on a flexible microphysical approach and, as the number of externally imposed parameters is minimised, allows the application in a wide range of climate regimes. ECHAM5-HAM predicts the evolution of an ensemble of microphysically interacting internally- and externally-mixed aerosol populations as well as their size-distribution and composition. The size-distribution is represented by a superposition of log-normal modes. In the current setup, the major global aerosol compounds sulfate (SU), black carbon (BC), particulate organic matter (POM), sea salt (SS), and mineral dust (DU) are included. The simulated global annual mean aerosol burdens (lifetimes) for the year 2000 are for SU: 0.80 Tg(S) (3.9 days), for BC: 0.11 Tg (5.4 days), for POM: 0.99 Tg (5.4 days), for SS: 10.5 Tg (0.8 days), and for DU: 8.28 Tg (4.6 days). An extensive evaluation with in-situ and remote sensing measurements underscores that the model results are generally in good agreement with observations of the global aerosol system. The simulated global annual mean aerosol optical depth (AOD) is with 0.14 in excellent agreement with an estimate derived from AERONET measurements (0.14) and a composite derived from MODIS-MISR satellite retrievals (0.16). Regionally, the deviations are not negligible. However, the main patterns of AOD attributable to anthropogenic activity are reproduced.

Comment and Reply on "Nd isotopic gradients in upper crustal magma chambers: Evidence for in situ magma-wall-rock interaction"

Geology ◽  
1991 ◽  
Vol 19 (2) ◽  
pp. 185
Author(s):  
Benjamin C. Schuraytz ◽  
Thomas A. Vogel ◽  
Leland W. Younker ◽  
G. Lang Farmer ◽  
Kathryn J. Tegtmeyer
Keyword(s):  
Wall Rock ◽  
Magma Chambers ◽  
Rock Interaction ◽  
Crustal Magma

scholarly journals CHEMICAL AND BIOLOGICAL INDICATORS FOR EVALUATION OF ARCTIC SOIL DEGRADATION AND ITS POTENTIAL TO REMEDIATION

2021 ◽  
Vol 29 (1) ◽  
pp. 33-39
Author(s):  
Tatiana S. Smirnova ◽  
Elena A. Mazlova ◽  
Olga A. Kulikova ◽  
Ilya M. Ostrovkin ◽  
Adam M. Gonopolsky ◽  
...  
Keyword(s):  
Biological Indicators ◽  
Climatic Conditions ◽  
Chloride Ions ◽  
The Arctic ◽  
Environmental Damage ◽  
Arctic Zone ◽  
Arctic Soils ◽  
Arctic Soil ◽  
Restoration Ability ◽  
High Concentrations

In recent years, significant efforts have been made to accelerate the economic development of the Arctic zone, leading to intense environmental pollution of this region, accompanied by the significant impact of accumulated environmental damage in the region. The solution to these problems is difficult due to the remoteness of these areas and severe climatic conditions. Therefore, it is important to evaluate the potential for restoration of arctic soils. For this purpose, various indicators are used, including biological ones. In the analyzed arctic soil samples, high concentrations of petroleum hydrocarbons (up to 47,000 mg/kg) and chloride-ions (0.10–0.14 wt %) were established. Microbioassay demonstrated a presence of hydrocarbon-oxidizing microorganisms: Penicillium, Azotobacter chroococcum, Bacillus subtilis, Pseudomonas oleovorans. A low enzymatic activity and specific Arctic climate point out a low self-restoration ability of the soil, demonstrated the need for its remediation. The microbioassay with microbial strains identification and soil remediation methods suitable for the Arctic zone were recommended.

Effects of stimulation on steroid output and perfusion medium flow rate in the isolated perfused rat adrenal gland in situ

1986 ◽  
Vol 109 (2) ◽  
pp. 279-285 ◽  
Author(s):  
J. P. Hinson ◽  
G. P. Vinson ◽  
B. J. Whitehouse ◽  
G. M. Price
Keyword(s):  
Flow Rate ◽  
Zona Glomerulosa ◽  
Clear Correlation ◽  
Perfusion Medium ◽  
Flow Rates ◽  
Vascular Elements ◽  
Medium Flow ◽  
High Concentrations ◽  
Adrenal Vasculature

ABSTRACT Using the in-situ, isolated, perfused rat adrenal system, the actions of adrenal stimulants on steroidogenesis and perfusion medium flow rates (under constant perfusion pump conditions) have been studied. In a series of 100 experiments, initial rates of corticosterone output and flow rates were found to be positively correlated, although there was no such relationship between initial rates of aldosterone output and flow rates. Furthermore, in stable perfusion conditions, bolus injections of ACTH increased both flow rate and steroid output in a dose-related manner. In individual experiments there was a clear correlation between corticosterone and flow, but the association between aldosterone secretion rate and flow was less evident. It is possible that this discrepancy arises because of temporal differences in the responses of these two steroids. Flow was also stimulated by dibutyryl cyclic AMP (dbcAMP), with correlations with steroid output similar to ACTH, but the specific zona glomerulosa stimulants angiotensin II amide and potassium ions had, if anything, inhibitory effects on flow, but only at high concentrations. The data suggest that ACTH and dbcAMP evoke specific responses in the adrenal vasculature, resulting in relatively decreased intraglandular vascular resistance. They furthermore suggest that the secretory functions of the inner adrenocortical zones are subject to the additional control of vascular elements in the intact gland. J. Endocr. (1986) 109, 279–285

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