scholarly journals Mineralogical and Geochemical Study of the Zeolitized Volcaniclastic Rocks of Petrota region, Evros Prefecture, Northeastern Greece

2020 ◽  
Vol 56 (1) ◽  
pp. 17
Author(s):  
Eleni Michailidou ◽  
Michael Vavelidis ◽  
Lambrini Papadopoulou ◽  
Nikolaos Kantiranis
Keyword(s):  
Major And Trace Elements ◽  
Volcanic Area ◽  
Southeastern Part ◽  
Quartz Crystals ◽  
Geochemical Composition ◽  
X Ray ◽  
Polarizing Microscope ◽  
Geochemical Study ◽  
Icp Ms ◽  
High Concentrations

The present work studies the tuffs associated with the volcanic area of the Paleogene Sheinovets caldera, located on the southeastern part of the Rhodope massif, in Bulgaria. Its purpose is to describe the mineralogical and geochemical composition of the zeolitized volcaniclastic deposits in the broader area of Petrota village, in the northwesternmost part of the Greek regional unit of Evros, in northeast Greece. The samples studied in this work were collected from seven (7) different locations, covering an area of almost 4 km in length and 2 km in width. Macroscopically, the samples display a greyish-green hue and they are widespread in the area of study. They often contain fragments of the crystalline metamorphic basement (mica-schists, phyllites, amphibolites, quartzites) and/or rhyolitic clasts. A rhyolitic outcrop of greyish-pink hue is observed in the Mavri Petra region, probably related to the Rupelian acid volcanism that occurred in the Sheinovets caldera. The mineralogy of the tuffs was studied under light polarizing microscope and using Scanning Electron Microscopy (SEM), and it was further confirmed by X-ray powder diffraction (XRPD) method. The initial matrix of the tuffs consisted predominantly of glass shards that are now partly or fully altered into zeolites and clay minerals, such as celadonite, displaying characteristic pseudomorphic structures. The dominant zeolite is clinoptilolite, while in some areas the presence of mordenite is also noticed. Feldspar phenocrysts are abundant, and they are represented by plagioclase and sanidine. Although quartz crystals can be observed under light-polarizing microscope solely in metamorphic fragments, the presence of silica polymorphs was also confirmed through SEM and XRPD analysis, with quartz and cristobalite prevailing. The mineralogical assemblage includes phenocrysts of biotite and in some cases amphiboles, while pyroxene, epidote, garnet, titanite, apatite, zircon, ilmenite, magnetite and rutile are additional minerals which have been identified locally in accessory quantities. Chemical analysis was carried out for major and trace elements, using the X-ray fluorescence (XRF) method and 4 Acid digestion ICP-MS analysis, respectively. The samples of Mavri Petra region, exhibit high concentrations in Cu, Pb, Mn, V, P and W. The analyzed concentrations of U in the area of Palaeokklisi are relatively high in comparison to the rest due to its proximity to a fault. Towards the northwestern study area, close to the Greek-Bulgarian border, the concentrations of Sr appear to be particularly high, probably because the area is closer to the volcanic centre.

scholarly journals Evaluation of sediment contamination by trace elements and the zooplankton community analysis in area affected by gold exploration in Southeast (SE) of the Iron Quadrangle, Alto Rio Doce, (MG) Brazil

2013 ◽  
Vol 25 (2) ◽  
pp. 150-157
Author(s):  
Cláudia de Lima e Silva ◽  
Adivane Terezinha da Costa ◽  
Giovanni Guimarães Landa ◽  
Herton Fabrício Camargos Fonseca ◽  
Aléssio Silveira
Keyword(s):  
Trace Elements ◽  
Reference Values ◽  
Zooplankton Community ◽  
Reference Value ◽  
Community Analysis ◽  
Major And Trace Elements ◽  
Geochemical Composition ◽  
Gold Exploration ◽  
Local Reference ◽  
High Concentrations

AIM: The aim was to verify the geochemical composition of sediments samples (riverbed and bank) and the relationship of the following elements: Al, As, Cd. Cr, Cu, Fe, Mn, Ni and Zn with the zooplankton community. METHODS: Bank and riverbed sediments were collected in four sampling points along the studied area, in June/2010 (dry season) and March/2011 (rainy season). Three types of analysis were performed: granulometric, mineralogical (by X-Ray diffractometer) and geochemical (by ICPOES), where for the last two types, only a fraction of silt/clay (<0.062 mm) was used, and the results were compared with the following reference values: Local Reference Value (Costa et al., 2010), Quality Reference Values (São Paulo, 2005), PEC and TEC values (MacDonald et al., 2000). For identification of the zooplankton community, riverbed and bank samples were collected in polyethylene bottles, suspended with deionized water (bank sample only), stained with Rose Bengal and preserved in formalin at 4%. RESULTS: As concentrations at Col sampled point were 18 times greater than the Local Reference Value (3.84 mg.kg-1). Cd concentrations were greater than the values established by the QRV (<0.5 mg.kg-1) and PEC (4.98 mg.kg-1) in almost all the sampled points, regarding seasonality. The following zooplanktonic species were identified: Arcella costata (Ehrenberg, 1847), Arcella discoides (Ehrenberg, 1843), Arcella vulgaris (Ehrenberg, 1830), Centropyxis aculeata (Ehrenberg, 1838), Centropyxis ecornis (Ehrenberg, 1841), Difflugia sp., Difflugia acuminata (Ehrenberg, 1838), Euglypha laevis (Perty, 1849), Trynema enchelys (Ehrenberg, 1938), Asplanchna priodonta (Gosse, 1850), and Bedelloida, with, approximately 81% belonging to the Protozoa group. CONCLUSIONS: The studied area, with the exception of the Tripuí point, was found to be impacted by historical gold exploration in the region, as well as by the growing urbanization. Within the elements considered to be the most toxic to the biota, As and Cd violated all their reference values. In spite of high concentrations of major and trace elements encountered at downstream points, testacea species were identified, suggesting that this group has the capacity to adapt to adverse situations.

scholarly journals GEOCHEMICAL CHARACTERIZATION OF BANANA, BURITI PALM, JUTE AND COIR FIBRES FOR USE AS BIOGEOTEXTILES FOR EROSION CONTROL

2018 ◽  
Vol 26 (3) ◽  
pp. 202-215 ◽  
Author(s):  
Charles Izuchukwu Egbujuo ◽  
Michael A. Fullen ◽  
Antonio J. T. Guerra ◽  
Alexander Iheanyi Opara
Keyword(s):  
Heavy Metal ◽  
Heavy Metal Contamination ◽  
Erosion Control ◽  
X Ray Diffraction ◽  
Soil System ◽  
Geochemical Composition ◽  
X Ray ◽  
Jute Cloth ◽  
High Concentrations ◽  
Banana Leaf

Geochemical analysis of selected plant fibres used as geotextiles for erosion control was conducted to evaluate their geochemical composition and to determine the elements that could potentially be nutrients for plants or cause heavy metal contamination in soils. Analysis of the samples was performed using X-ray Diffraction and X-ray Fluorescence spectrometry. Results revealed that potassium concentrations varied from 3.63% in jute-mat (India)-50.73% in banana-leaf (São Romão, Brazil), with a mean of 27.17%. Similarly, calcium concentrations varied from 0.09% in banana-leaf (São Romão) –37.0% in banana-leaf/stem (Oleo, Brazil). Iron concentrations varied from 0.15% in banana-leaf/stem samples (Oleo) –4.47% in jute-cloth (India). Since banana-leaf/stem had the highest concentration of macro-nutrients, it is therefore proposed that banana-leaf has the highest potential for adding nutrients to the soil system when biodegraded. In addition, heavy metal analysis of the samples revealed that none of the fibres have high concentrations that may contaminate the soil upon decomposition.

Characterization of Uranium Speciation in a Metallic Matrix

2002 ◽  
Vol 757 ◽  
Author(s):  
Gini Curran ◽  
Patrick G. Allen ◽  
Daniel F. Caputo ◽  
Ken R. Czerwinski
Keyword(s):  
Gamma Spectroscopy ◽  
Metallic Matrix ◽  
Elemental Content ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Uranium Speciation ◽  
Icp Ms ◽  
High Concentrations ◽  
X Ray Absorption

ABSTRACTThree metallic slag samples recovered from the site of their inadvertent creation several decades after the fact were sectioned and analyzed to determine uranium speciation to evaluate environmental behavior as well as assess proliferation resistance of the waste form. Uranium concentration in the highly inhomogeneous samples was up to 5% by weight as determined by gamma spectroscopy. Sample sections were milled in a hardened steel ball mill for x-ray absorption spectroscopy analysis (XAS). Powders were digested in a mixture of heated concentrated nitric acid and peroxide and analyzed for elemental content using ICP-AES and ICP-MS. Though elemental content of the samples varied widely, high concentrations of Al were consistently found. Other metals of significance were Ti, Fe, Ni, Cu, Zn, and Sn. High Pb concentrations were occasionally found. XAS analysis revealed the samples contained primarily uranyl and another phase identified as a uranium-aluminum melt.

scholarly journals HYDROCHEMICAL CHARACTERISTICS AND GEOTHERMOMETRY APPLICATIONS OF HOT GROUNDWATER IN EDIPSOS AREA, NW EUBOEA (EVIA), GREECE

2017 ◽  
Vol 50 (2) ◽  
pp. 720
Author(s):  
C. Kanellopoulos ◽  
M. Christopoulou ◽  
M. Xenakis ◽  
P. Vakalopoulos
Keyword(s):  
Chemical Composition ◽  
Hot Springs ◽  
Sea Water ◽  
Analytical Data ◽  
Major And Trace Elements ◽  
Geochemical Study ◽  
Icp Ms ◽  
Active Tectonic ◽  
High Participation ◽  
Recent Volcanism

In Edipsos area many hot springs occur, as a result of both active tectonic of the area and recent volcanism (Lichades volcanic center). A geochemical study of Edipsos hot groundwaters was undertaken, in order to assess the hydrochemistry of hot springs from Edipsos and re-evaluate the geothermal situation of the area. For that purpose, 12 water samples were collected and analyzed by Spectrophotometry for the main ions and by AAS, ICP-OES and ICP-MS for major and trace elements. The interpretation of the analytical data showed that the geochemistry of Edipsos hot groundwaters is controlled by three factors i) a deep magmatic source, ii) the chemical composition of the local rocks (ultramafic and carbonates) and iii) sea water. The application of chemical geothermometers is problematic because of the chemical composition of the hot groundwaters and especially the high participation of the sea water. The temperature which derives from the use of Na-K-Ca geothermometer is greater than 160°C. Although, several studies have conducted in the area still remain unanswered questions concerning the underground circulation of the hot groundwater, in which only deep drilling data could give answers.

Major and Trace Elements in the Humic Acid

2018 ◽  
Author(s):  
Zoltán Kis ◽  
Katalin Gméling ◽  
Tímea Kocsis ◽  
János Osán ◽  
Mihály András Pocsai ◽  
...  
Keyword(s):  
Trace Elements ◽  
Humic Acid ◽  
Activation Analysis ◽  
Analytical Techniques ◽  
Major And Trace Elements ◽  
Prompt Gamma Activation Analysis ◽  
Prompt Gamma ◽  
Gamma Activation ◽  
X Ray ◽  
Precise Analysis

We present precise analysis of major and trace elements of the humic acid. We used three different element analytical techniques in our investigations as prompt-gamma activation analysis (PGAA), neutron activation analysis (NAA) and X-ray fluorescence (XRF) analysis was carried out. We identified 42 elements in our sample.

Hingganite-(Nd), Nd2□Be2Si2O8(OH)2, a new gadolinite-supergroup mineral from Zagi Mountain, Pakistan

2020 ◽  
Vol 58 (5) ◽  
pp. 549-562
Author(s):  
Anatoly V. Kasatkin ◽  
Fabrizio Nestola ◽  
Radek Škoda ◽  
Nikita V. Chukanov ◽  
Atali A. Agakhanov ◽  
...  
Keyword(s):  
New Mineral ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Average Chemical Composition ◽  
X Ray ◽  
Conchoidal Fracture ◽  
Icp Ms ◽  
Optical Axes ◽  
Mohs Hardness ◽  
Khyber Pakhtunkhwa Province

ABSTRACT Hingganite-(Nd), ideally Nd2□Be2Si2O8(OH)2, is a new gadolinite group, gadolinite supergroup mineral discovered at Zagi Mountain, near Kafoor Dheri, about 4 km S of Warsak and 30 km NW of Peshawar, Khyber Pakhtunkhwa Province, Pakistan. The new mineral forms zones measuring up to 1 × 1 mm2 in loose prismatic crystals up to 0.7 cm long, where it is intergrown with hingganite-(Y). Other associated minerals include aegirine, microcline, fergusonite-(Y), and zircon. Hingganite-(Nd) is dark greenish-brown, transparent, has vitreous luster and a white streak. It is brittle and has a conchoidal fracture. No cleavage or parting are observed. Mohs hardness is 5½–6. Dcalc. = 4.690 g/cm3. Hingganite-(Nd) is non-pleochroic, optically biaxial (+), α = 1.746(5), β = 1.766(5), γ = 1.792(6) (589 nm). 2Vmeas. = 80(7)°; 2Vcalc. = 84°. Dispersion of optical axes was not observed. The average chemical composition of hingganite-(Nd) is as follows (wt.%; electron microprobe, BeO, B2O3, and Lu2O3 content measured by LA-ICP-MS; H2O calculated by stoichiometry): BeO 9.64, CaO 0.45, MnO 0.10, FeO 3.03, B2O3 0.42, Y2O3 8.75, La2O3 1.63, Ce2O3 12.89, Pr2O3 3.09, Nd2O3 16.90, Sm2O3 5.97, Eu2O3 1.08, Gd2O3 5.15, Tb2O3 0.50, Dy2O3 2.50, Ho2O3 0.33, Er2O3 0.84, Tm2O3 0.10, Yb2O3 0.44, Lu2O3 0.04, ThO2 0.13, SiO2 23.55, H2O 2.72, total 100.25. The empirical formula calculated on the basis of 2 Si apfu is (Nd0.513Ce0.401Y0.395Sm0.175Gd0.145Pr0.096Dy0.068La0.051Ca0.041Eu0.031Er0.022Tb0.014Yb0.011Ho0.009Tm0.003Th0.003Lu0.001)Σ1.979(□0.778Fe2+0.215Mn0.007)Σ1.000(Be1.967B0.062)Σ2.029Si2O8.46(OH)1.54. Hingganite-(Nd) is monoclinic, space group P21/c with a = 4.77193(15), b = 7.6422(2), c = 9.9299(2) Å, β = 89.851(2)°, V = 362.123(14) Å3, and Z = 2. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 6.105 (95) (011), 4.959 (56) (002), 4.773 (100) (100), 3.462 (58) (102), 3.122 , 3.028 (61) (013), 2.864 (87) (121), 2.573 (89) (113). The crystal structure of hingganite-(Nd) was refined from single-crystal X-ray diffraction data to R = 0.034 for 2007 unique reflections with I &gt; 2σ(I). The new mineral is named as an analogue of hingganite-(Y), hingganite-(Yb), and hingganite-(Ce), but with Nd dominant among the rare earth elements.

scholarly journals A small molecule compound with an indole moiety inhibits the main protease of SARS-CoV-2 and blocks virus replication

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shin-ichiro Hattori ◽  
Nobuyo Higashi-Kuwata ◽  
Hironori Hayashi ◽  
Srinivasa Rao Allu ◽  
Jakka Raghavaiah ◽  
...  
Keyword(s):  
Small Molecule ◽  
Covalent Bond ◽  
Amino Acid Residues ◽  
X Ray ◽  
Viral Breakthrough ◽  
Main Protease ◽  
Small Molecule Compound ◽  
Polar Interactions ◽  
High Concentrations

AbstractExcept remdesivir, no specific antivirals for SARS-CoV-2 infection are currently available. Here, we characterize two small-molecule-compounds, named GRL-1720 and 5h, containing an indoline and indole moiety, respectively, which target the SARS-CoV-2 main protease (Mpro). We use VeroE6 cell-based assays with RNA-qPCR, cytopathic assays, and immunocytochemistry and show both compounds to block the infectivity of SARS-CoV-2 with EC50 values of 15 ± 4 and 4.2 ± 0.7 μM for GRL-1720 and 5h, respectively. Remdesivir permitted viral breakthrough at high concentrations; however, compound 5h completely blocks SARS-CoV-2 infection in vitro without viral breakthrough or detectable cytotoxicity. Combination of 5h and remdesivir exhibits synergism against SARS-CoV-2. Additional X-ray structural analysis show that 5h forms a covalent bond with Mpro and makes polar interactions with multiple active site amino acid residues. The present data suggest that 5h might serve as a lead Mpro inhibitor for the development of therapeutics for SARS-CoV-2 infection.

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