EM - Escola de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6
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A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.
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Item Amphimedon viridis marine sponge as metal bioindicator for Al, Ba, Cr, Fe and Mn.(2022) Moreira, Ronan Pereira Garcias; Krohling, Werther; Ferreira Júnior, Paulo Dias; Abreu, Adriana Trópia de; Nalini Júnior, Hermínio Arias; Schmitt, Elisângela Flávia Pimentel; Coutinho, Silvia Cruz Goes; Endringer, Denise CoutinhoBACKGROUND: Bivalves, oysters, and mussels are accepted as biological indicators for marine pollutants. Heavy metals biomonitoring on the environment was this study objective using A. viridis compared with Perna perna (mollusk bivalve). The area studied included Ilha Pituã in Vila Velha – ES and Ilha do Boi and Camburi Garden Beach in Vitoria - ES. METHODS: The sample collection comprised seawater, mussel (P. perna) and sponge (A. viridis). Al, As, Ba, Cr, Cu, Fe, Pb, Mn, K, Ti and Zn were analyzed using ICP OES. RESULTS For metal studied Al, Ba, Cr, Fe and Mn presented greater accumulation in A. viridis than in P. perna. The metal concentrations detected in seawater, sponge, and mussel could be related using PCA with 79.26% total variance demonstrating that A. viridis bioaccumulated more metals than P. perna. CONCLUSION: Sponge metal accumulation reflected not only spatial metal variation but also seasonal changes.Item Mineral content in honey and pollen from native stingless bees Tetragonisca angustula (Latreille, 1811) in the Iron Quadrangle, Brazil.(2020) Oliveira, Fernanda Ataide de; Abreu, Adriana Trópia de; Nascimento, Nathália de Oliveira; Froes, Roberta Eliane Santos; Nalini Júnior, Hermínio Arias; Itabaiana, Yasmine AntoniniThe objective of this work was to determine the mineral content of honey and pollen of the Brazilian native Jata ı bee (Tetragonisca angustula) sampled at nine sites in the so-called Iron Quadrangle region of the State of Minas Gerais, Brazil. Twenty chemical elements were determined in the honey and pollen samples: Al, Ba, Ca, Co, Cu, Fe, Ga, In, K, Li, Mg, Mn, Mo, Na, Ni, P, S, Sr, V, and Zn. Analysis of the data using ANOVA and Tukey’s test (p ¼ .05) revealed statistically significant differences between the mineral contents of honey and pollen, as well as between the samples from different locations. The score plot and loading plot diagrams from factor analysis with Varimax rotation were able to classify the honey and pollen samples according to their geographical origin. The factor analysis separated the sites according to the similarities of the chemical concentrations. These results were related to the geogenic and anthropic contributions of the sites. Therefore, honey and pollen of Jata ı bees could also serve as bioindicators.Item Determination of rare earth elements in Fe-minerals using external calibration by LA-ICP-MS and application on Cauê Iron Formation (Brazil).(2020) Sousa, Denise Versiane Monteiro de; Abreu, Adriana Trópia de; Sampaio, Geraldo Magela Santos; Lana, Cristiano de Carvalho; Rodrigues, Daniel Aparecido da Silva; Nalini Júnior, Hermínio AriasThe rare earth elements (REE) composition in Fe-mineral phases is an important tool in iron formation studies to obtain information about parent rocks and environmental and paragenetic processes. However, the determination of REE presents some difficulties, such as the low concentration of these elements, matrix complexity and lack of iron matrix certified reference materials. The aim of the present work is to propose an analytical method to determine the REE plus Y (REE + Y) contents at trace levels in Fe-(hydr)oxides by the laser ablation ICPquadrupoleMS technique, using external calibration. The calibration curves were obtained from analyses of reference materials with different matrices, and the analytical conditions were checked on the NIST 614 glass. The linearity (R2 ≥ 0.98), limit of detection (0.002–0.044 μg g−1), limit of quantification (0.008–0.146 μg g−1), recovery (88.4–112.4%), and intraday (0.1–14.1%) and interday (1.6–17.8%) precision were systematically assessed. The results obtained showed that the method is fit for the purpose and showed evidence of a nonsignificant interference of the matrix. Thus, the developed procedure was applied in the analyses of magnetite, martite, hematite, and goethite grains from Cauê Iron Formation (Brazil). The REE + Y patterns of the minerals are consistent with the previous study of bulk analyses on whole rocks and highlight the postdepositional signature of these elements in banded iron formations.Item Geochemical evaluation of bottom sediments affected by historic mining and the rupture of the Fundão dam, Brazil.(2020) Reis, Deyse Almeida dos; Nascimento, Laura Pereira do; Abreu, Adriana Trópia de; Nalini Júnior, Hermínio Arias; Roeser, Hubert Mathias Peter; Santiago, Aníbal da FonsecaThe rupture of the Fundão dam released about 39 million m3 of tailings into the Rio Doce/Brazil. The sediment load increase in the affected rivers has become a concern. As such, this article provides recent information about the region. In addition, based on past studies in the region, it shows the magnitude and dynamics of the environmental impacts caused by the rupture of the dam on the bottom sediments. Sediment samples in different seasonal periods were collected at eleven sampling stations located along the Gualaxo do Norte River, the first tributary of the Rio Doce affected by the environmental disaster. These sediments underwent physical, chemical, and granulometric analyses for their organic, metal, and semimetal content. The contamination factor and the enrichment factor of the samples also were calculated. To evaluate the anthropogenic contributions to sediment metal concentrations, reference values (regional background values) for the Gualaxo do Norte River were used. The results indicate that, in the sampling stations not affected by the disaster, the concentrations of the metals and semimetals reflect the geology of the Quadrilátero Ferrífero. However, in the area affected by the environmental disaster, there were changes in the chemical and physical properties of the bottom sediment, mainly in the concentrations of iron, organic matter, and fine sediment fractions. This was reflected in the contamination factors and enrichment factors calculated for the sediments of the sampling stations. Iron and manganese concentrations in sediments are much higher than other rivers in the world that are unaffected by mining activities. The observed changes in the bottom sediments of the river suggest a need for constant monitoring of the iron because the iron oxide minerals present in silt and clay have a high adsorption capacity. In the long term, these factors may contribute to the decrease of the quality of these sediments and consequently of the waters and biota present in these environments.Item The fate of a Neoproterozoic intracratonic marine basin : trace elements, TOC and IRON speciation geochemistry of the Bambuí Basin, Brazil.(2019) Hippertt, João Pedro Torrezani Martins; Caxito, Fabrício de Andrade; Uhlein, Gabriel Jubé; Nalini Júnior, Hermínio Arias; Sial, Alcides Nóbrega; Abreu, Adriana Trópia de; Nogueira, Leonardo BrandãoNeoproterozoic marine systems are associated with major paleoecological changes that took place in the Ediacaran and during the Ediacaran-Cambrian transition. During this timespan, the Bambuí basin located on east Brazil held a peculiar paleoenvironmental scenario. Due to its intracratonic evolution, the basin was partially disconnected from neighboring open marine systems. This setting raises a very interesting opportunity to understand how an isolated Neoproterozoic marine system evolved in contrast with typical (globally connected) open marine systems. To understand the paleoenvironmental changes that took place in the Bambuí basin, we investigate the pre-glaciogenic deposits of the Carrancas Fm and the post-glaciogenic mixed (shale-carbonate) successions of the Bambuí Group. Through the analysis of iron speciation, TOC, trace element and C-O isotope systematics, our study suggests a very complex environmental evolution. Firstly, our samples are marked by strong contamination of detrital continental material that can be related to an increased bioproductivity on both the Carrancas Fm. and lower Bambuí group stratigraphic units, and provenance data show that all studied sediments probably shared common source areas. Iron speciation data, Ce anomalies and RSE enrichments shows that lower Bambuí Group stratigraphic units were likely deposited in an open marine scenario featuring high bioproductivity in shallow waters and euxinic incursions in predominant anoxic/ferruginous bottom waters. On the other hand, upper Bambuí stratigraphic units register a marine evolution in a restricted scenario, where anoxic ferruginous conditions probably reached surface waters. Finally, our data show that the lack of oceanic connection prevented the re-supply of marine sulfate, RSE, bionutrients and ultimately of dissolved oxygen which may have decreased biological activity and probably hindered biological evolution, preventing the rise of a typical modern-like Cambrian ecosystem. In this sense, our data suggest that oceanic connectivity and proper re-supply of inorganic marine input were important features in the development of complex life in the EdiacaranCambrian environment.Item In-situ LA-ICP-MS and EMP trace element analyses of hematite : insight into the geochemical signature of the Neoproterozoic Urucum iron formation, Brazil.(2019) Souza, Fernando Ribeiro de; Nalini Júnior, Hermínio Arias; Abreu, Adriana Trópia deHematite hosted in iron formations (IFs) is widely held as a transformation of (bio)chemical precipitates, which may register depositional conditions and sources responsible for the origin of these enigmatic rocks. Consequently, this is an attractive target to mineral-specific geochemical investigations aiming at distinguishing primary signatures from ore-related transformations and terrigenous contamination. This study reports in situ Electron Microprobe (EMP) and Laser AblationInductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) analyses of hematite grains from the Neoproterozoic Urucum IF, Jacadigo-Boqui Gr. The hematite grains were divided into three main morpho-textural types: (i) anhedral, micro-crystalline hematite (Hm1); (ii) coarser, subhedral to euhedral, microspecular (Hm2) and (iii) microplaty (Hm3) hematite. Factor analysis (FA) was used to trace underlying relationships among the trace elements (TEs). The identified factors were correlated to: (i) substitutions in the hematite structure (F3a, MgO-MnO-Al2O3-TiO2; and F1b, Al-Ti-V); (ii) mineral inclusions (F1a, SiO2; F2a, P2O5-CaO-MgO; and F2b, Mg-Mn-Sr); (iii) hydrogenous and diagenetic incorporation (F3b, Th-Zr-Cu and Ba-REE; F4b, Si-U-Hf). The TE compositions are broadly consistent in all hematite types; this trend suggests limited post-depositional overprinting. Nearly isochemical signatures show that transformation of ferrihydrite to hematite and the subsequent recrystallization of this mineral were dominated by solid-state processes under high Eh. Elements exclusively incorporated in the hematite structure (Al, Ti, V) did not show significant fractionation with increasing recrystallization. Replacement and solution precipitation also occurred, albeit to a lesser extent. The recrystallization of Hm1 to Hm2 and Hm3 was likely controlled by texture and assisted by pressure and fluid circulation. Warm, alkaline, basin brines were also responsible for the dissolution of gangue minerals, particularly chert. Consequently, elements associated with mineral inclusions (Si, P, Ca, Mg, Mn, and Sr) decrease in abundance from Hm1 to Hm2 and Hm3. Ptygmatic quartz veinlets and chert dissolution pods attest to silica leaching and volume reduction leading to hypogene enrichment. Supergene enrichment resulted in ubiquitous secondary porosity, but generally did not affect the composition of the hematite grains. Non-CHARAC Zr/ Hf ratios suggest active HFSE fractionation processes. Super-chondritic ratios record basin seawater enriched in Zr as a consequence of the fractionation of Hf onto amorphous silica, registered by sub-chondritic Zr/Hf ratios and a correlation between Si and Hf in factor F4b. Distinctively seawater-like REE pasterns suggest a common precursor hydrogenous phase. Consistent true negative Ce anomalies and generally low Th/U ratios, together with the relatively common occurrence of hematite peloids, suggest that the precursor ferrihydrite particles were deposited and accumulated near the water-sediment interface, in a well-oxygenated shallow water setting. This implies the existence of a discrete chemocline separating the deep ferruginous waters from oxygenated shallow waters.Item Elemental and stable isotopes geochemistry of Paleoproterozoic dolomites from Fecho do Funil Formation, Quadrilátero Ferrífero - Brazil(2017) Nogueira, Leonardo Brandão; Oliveira, Vinícius Queiroz; Leite, Mariangela Garcia Praça; Ali, Arshad; Sampaio, Geraldo Magela Santos; Abreu, Adriana Trópia de; Nalini Júnior, Hermínio Arias; Banerjee, Neil R.Geochemical and stable isotopic characteristics of thirteen samples taken from Paleoproterozoic Fecho do Funil Formation, Quadril atero Ferrífero, Brazil have been analyzed to investigate the depositional conditions and source of rare earth elements (REEs) in Cumbi quarry dolomites. The major oxides such as CaO and MgO show variable compositions ranging from 20 to 29 wt % and 14e21 wt % respectively in most of the samples. The contents of loss on ignition (LOI) are lower (26e42 wt %) than that of the pure dolomite (~48 wt %). These mass discrepancies are compensated by other oxides including Al2O3 (1.9 e18.7 wt %), Fe2O3 (1.2e6.1 wt %), and K2O (0.5e6.8 wt %) that had been incorporated into the dolomite samples by the contamination of terrigenous input. Further, SREE contents (20e101 ppm) display significant variation that also corroborate with contamination of studied samples by detrital materials. The regression lines of SREE against Al2O3 (R2 ¼ 0.96), Fe2O3 (R2 ¼ 0.65), Ni (R2 ¼ 0.94), Cr (R2 ¼ 0.95), Th (R2 ¼ 0.98), and Sc (R2 ¼ 0.98) show positive correlation which is probably associated with the input of terrigenous materials during the deposition of Cumbi quarry dolomites. On the other hand, a negative correlation between SREE and CaO combined with a large variation in Y/Ho (27e50) is also interpreted as the sea-water like REE patterns have been masked by the contribution of variable amounts of terrigenous materials in Cumbi quarry dolomites. All the dolomite samples analyzed from the Fecho do Funil Formation exhibit a subtle negative cerium anomaly (Ce/Ce* ¼ 0.85e0.95). The dolomites from Cumbi quarry e Fecho do Funil Formation show narrow variations in Eu anomalies (Eu/Eu* ¼ 1.02 to 1.25). The positive correlation between Eu with Zr, Th and Y supports the non diagenetic influence on this element (R2 ¼ 0.94, 0.98, 0.84 respectively). Eu contents, in this study show significant positive correlation with Al2O3 (R2¼0.96), suggesting the detrital origin. The d13CVPDB (þ6.0 to þ7.2‰) and d18OVPDB ( 10.9 to 10.4‰) values in our samples display a narrow range which are identical to those shown by successions, characterized by positive carbon excursions, deposited during the Lomagundi event. We infer that the elevated carbon isotope values of the Fecho do Funil dolomites likely reflect primary carbon isotope compositions.Item Pollen storage by stingless bees as an environmental marker for metal contamination : spatial and temporal distribution of metal elements.(2018) Nascimento, Nathália de Oliveira; Nalini Júnior, Hermínio Arias; Oliveira, Fernanda Ataide de; Abreu, Adriana Trópia de; Antonini, YasmineSince the middle of the 20th century, human activities have led to overall ecosystem contamination and to major modifications in landscape structure and composition. Mining activities represent a major source of environmental contamination by metal residues. The objective of our study was to evaluate the presence of heavy metals and other elements on stingless bee pollen, and compare them to samples of Suspended Particulate Material (SPM) in five points a Mineral Province, in Brazil. More than 50 elements were identified by ICP-OES and ICP-MS, after microwave digestion. Overall, we found a strong relation among elements present on pollen and SPM. Samples from the four areas exhibited higher levels of minerals compared to the reference site. Mineral levels varied widely within the two seasonal periods. Some elements, like Pb, Cd, As, Cu, Zn, and Fe were found at levels considered potentially toxic to human health. Pollen stored by stingless bees was a successful bioindicator, and demonstrated the value of quantitative ecological information for detecting air pollution.Item Quantitative analysis of plant leaf elements using the LA-ICP-MS technique.(2019) Diniz, Adriana Pedrosa; Kozovits, Alessandra Rodrigues; Lana, Cristiano de Carvalho; Abreu, Adriana Trópia de; Leite, Mariangela Garcia PraçaThe use of Laser Ablation coupled to Mass Spectrometry is a promising technique for analysis of plant tissue elements because it has advantages over conventional digestion techniques such as reduced levels of contamination and sample preparation time, possibility of spatial distribution analysis of elements, high number of repetitions, among others. This technique still has some limitations, especially with regard to calibration, which may result in inaccurate chemical analyses. The present study aims to compare two types of analyzers (quadrupole and magnetic sector field) regarding precision and accuracy. Certified material was examined, and also plant material analyzed by both solution in inductively coupled plasma optical emission spectrometry (ICP OES) and by laser ablation methods. It was observed that the magnetic sector field analyzer gave better results in relation to precision (relative standard deviation - RSD) and accuracy (recovery). An elemental composition pattern similar to that of the sample to be analyzed is relevant to validate the methodology for the analysis of leaves collected under different environmental conditions. Thus, pulverized Eremanthus erytropappus leaves were suggested as a second type of validation standard to be used in analyzes of plants belonging to the Atlantic and Cerrado Forest biomes.Item Evaluation of matrix effect on the determination of rare earth elements and As, Bi, Cd, Pb, Se and In in honey and pollen of native Brazilian bees (Tetragonisca angustula – Jataí) by Q-ICP-MS.(2017) Oliveira, Fernanda Ataide de; Abreu, Adriana Trópia de; Nascimento, Nathália de Oliveira; Froes, Roberta Eliane Santos; Itabaiana, Yasmine Antonini; Nalini Júnior, Hermínio Arias; Lena, Jorge Carvalho deBees are considered the main pollinators in natural and agricultural environments. Chemical elements from honey and pollen have been used for monitoring the environment, the health of bees and the quality of their products. Nevertheless, there are not many studies on honey and pollen of native Brazilian bees. The goal of this work was to determine important chemical elements (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Lu and Yb) along with As, Bi, Cd, Pb, Se and In, in honey and pollen of native Brazilian bees, assessing analytical interferences from the matrix. A proposed analytical method was developed for these elements by quadrupole ICP-MS. Matrix effect was verified in honey matrix in the quantification of As, Bi and Dy; and in pollen matrix for Bi, Cd, Ce, Gd, La, Pb and Sc. The quality of the method was considered satisfactory taking into consideration the recovery rate of each element in the spiked solutions: honey matrix (91.6–103.9%) and pollen matrix (94.1–115.6%). The quantification limits of the method ranged between 0.00041 and 10.3 μg L−1 for honey and 0.00041–0.095 μg L−1 for pollen. The results demonstrate that the method is accurate, precise and suitable.