Geochemical Transactions最新文献

{"title":"A comparative study of the risk assessment and heavy metal contamination of coastal sediments in the Red sea, Egypt, between the cities of El-Quseir and Safaga","authors":"Ahmed R. Elgendy,&nbsp;Abd El Mohsen S. El Daba,&nbsp;Mohamed A. El-Sawy,&nbsp;Ahmed E. Alprol,&nbsp;Ghada Y. Zaghloul","doi":"10.1186/s12932-024-00086-8","DOIUrl":"10.1186/s12932-024-00086-8","url":null,"abstract":"<div><p>This study aimed to assess the influence of pollution on the quality of sediments and the risks associated with El-Qusier and Safaga Cities, Red Sea, Egypt, during 2021, divided into four sectors, using multiple pollution indices. To achieve that, we evaluated the metal pollution index (MPI), contamination factor (Cf), pollution load index (PLI), contamination security index (CSI), and anthropogenicity (Anp%). Moreover, carcinogenic and non-carcinogenic risks are used for human health hazards. Results indicated that Mn and Fe recorded the highest concentrations, whereas Cd had the lowest. El-Quseir City sediments were found the following metal ions: Fe &gt; Mn &gt; Ni &gt; Zn &gt; Cu &gt; Co &gt; Pb &gt; Cd, where the order in the Safaga City was: Fe &gt; Mn &gt; Zn &gt; Ni &gt; Cu &gt; Pb &gt; Co &gt; Cd. MPI &gt; 1, this is alarming in the study area due to heavy metal pollution. In addition, C_<i>f</i> &lt; 1 in all metals except Cd with contamination degree CD ranged from low to considerable contamination in El-Qusier city. In contrast, contamination ranged from significant to very high in Safaga city. PLI &lt; 1 is lower than the reference at all monitored stations. CSI values ranged from relatively low to moderate. Besides Cd, data reflect each element's low environmental danger (Eri^Me40). This study's risk index (RI) is low to moderate in Sector 1 and high to extremely high in Sector 2. HQ and HI index &lt; 1 means it is safe for human health in order: HI _ingestion &gt; HI _dermal. CSR for different pathways was recorded as dermal &gt; ingestion, in which total CSR for all paths is considered harmful, and the cancer risk is troublesome and higher than the reference ranges of 1 × 10^–6–1 × 10^–4. In conclusion, the examined heavy metals provide environmental hazards across the assessed locations.</p></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"25 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-024-00086-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140821077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemical dispersion of gold-bearing quartz veins in the Wadi Abu Khusheiba area in Southern Jordan","authors":"Mariam Mosleh,&nbsp;Jasmi Hafiz Abdul Aziz,&nbsp;Muhammad Hatta Roselee,&nbsp;Ahmed Al-Shorman,&nbsp;Mahmoud Al Tamimi,&nbsp;Abdelkarim Alsoudi","doi":"10.1186/s12932-024-00085-9","DOIUrl":"10.1186/s12932-024-00085-9","url":null,"abstract":"<div><p>This study delves into the geochemical dispersion of gold-bearing quartz veins in the Wadi Abu Khusheiba area, southern Jordan, with a focus on uncovering the complex patterns of mineralization and their geological significance. Employing an in-depth geochemical analysis of 24 rock samples from the region, we identified that these samples are predominantly hosted by oversaturated rhyolitic rocks, characterized by high SiO₂ content and abundant free Quartz and orthoclase minerals. The mineralized zone of the quartz veins is particularly notable for its gold and silver concentrations, with maximum values reaching up to 5 ppm for gold and 18 ppm for silver. Our investigation into the elemental correlations revealed nuanced relationships, dependent on the 21 sample and analyzed at confidence level of (85%). Contrary to initial assumptions, we did not find a significant positive correlation between gold (Au) and arsenic (As), nor significant negative correlations between gold and other trace elements. These insights are critical for understanding the geochemical behavior of gold in the area and offer a nuanced view of elemental associations. The results of this study are significant for both academic research and practical exploration. They enhance our comprehension of the geological history and mineralization processes in Wadi Abu Khusheiba, providing valuable data that can inform future exploration strategies and deepen our understanding of mineral deposition in similar geological settings. This research not only contributes to the scientific community’s knowledge of the area’s geochemistry but also has potential implications for the mining and exploration industries.</p></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"25 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-024-00085-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140012561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of some heavy metal accumulation in different organs on fish quality from Bardawil Lake and human health risks assessment","authors":"Ghada Y. Zaghloul,&nbsp;Hoda A. Eissa,&nbsp;Amira Y. Zaghloul,&nbsp;Mahmoud S. Kelany,&nbsp;Mohamed A. Hamed,&nbsp;Khalid M. El Moselhy","doi":"10.1186/s12932-023-00084-2","DOIUrl":"10.1186/s12932-023-00084-2","url":null,"abstract":"<div><p>Bardawil Lake is a unique aquatic ecosystem that provides a habitat for various fish and other marine organisms. This study aimed to analyze the quality of fish species to prove that this lake is free of pollution, not other Egyptian lakes, due to the accumulation of some heavy metals (Cd, Pb, Cu, and Zn) in various tissues of fish species that were caught from this lake. Thirty-five fish samples were caught during the Spring of 2018 from seven different species: <i>Mugil cephalus, Liza auratus, Sparus aurata, Dicentrarchus labrax, Siganus rivulatus, Anguilla angilla, and Solae solea</i>. The Association of Official Analytical Chemists methods using a spectrophotometer determined the biochemical composition. In contrast, atomic absorption spectrometry (AAS) was employed to determine the heavy metals expressed by µg/g wet weight. Results exposed that the accumulation of essential micronutrient (Cu, Zn) content was higher than toxic elements (Cd &amp; Pb) in muscles in order to Zn &gt; Cu &gt; Pb &gt; Cd. Muscles &lt; gills &lt; liver in order of all metals except Pb with order muscles &lt; liver &lt; gills. The metals studied in the muscles were lower than those set by the WHO and the EU standards. The carcinogenic risk with lower allowable limits of 1 × 10^–6 to 1 × 10^–4 in both normal and high consumption groups; target and total target hazard quotients (THQ &amp; HI) in muscles were &lt; 1. The biochemical composition level was highest in the liver, except for protein, which was highest in muscle for all fish species. There is no evidence of harmful contaminants in the muscular tissue of the fish sampled from Bardawil Lake, although fishing activity. However, customers should know that health concerns may be associated with overeating fish.</p></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"25 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-023-00084-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139416828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic implications of Th/U, Th/K, and U/K ratios for U mineralizations: A case study from El-Missikat and El-Erediya shear zones, Eastern Desert, Egypt","authors":"Mahmoud Abdel-Hakeem,&nbsp;Mohamed El-Tahir,&nbsp;Ehab Abu Zeid,&nbsp;Hassan Rageh","doi":"10.1186/s12932-023-00083-3","DOIUrl":"10.1186/s12932-023-00083-3","url":null,"abstract":"<div><p>The current work is an attempt to reveal the possible utilization of the radiometric measurements to build-up a complete genetic scenario for magmatic, hydrothermal, and supergene uranium mineralization. For this purpose, ground gamma-ray survey was performed through the exploratory tunnels dug perpendicular to El-Missikat and El-Erediya shear zones, the Central Eastern Desert of Egypt. Contents of U, Th, and K were measured for the host pink granite (e.g., avg.15.94 U ppm, 35.62 Th ppm, and 6.63% K), alteration zones (brecciation, silicification, greisenization, kaolinization and hematitization) (e.g., avg. 124.01 U ppm, 63.67 Th ppm, and 3.13% K), and mineralized silica veins (e.g., avg. 312.65 U ppm, 92.22 Th ppm, and 2.62% K). All of these data were graphically represented as correlation plots of Th vs. U, Th/U vs. U, Th vs. K, and U/K vs. Th/K. The overall results indicate magmatic, hydrothermal, and supergene sources of El-Missikat and El-Erediya U mineralization. The magma-derived U contents are enclosed mainly in the pink granite that is mostly characterized by normal Th/U (2.5–5) and Th/K ratios (3–5*10^–4). The hydrothermal processes through the alteration zones and mineralized silica veins are reflected by the weak correlation of Th with U (e.g. r = 0.13 and − 0.39), the strong negative correlation of Th/U ratio with U (e.g. r = − 0.82), 2.5˃Th/U˃0.1, Th/K˃5*10^–4, Th/K &lt; 3*10^–4, and the strong positive correlation of U/K with Th/K (e.g. r = 0.91) as well as the occurrence of thorite, columbite, xenotime and hydrothermal zircon (0.5 &gt; Th/U ≤ 0.1). Afterwards, the hydrothermal mineralization underwent some degrees of chemical weathering that resulted in supergene U mineralization whose fingerprints can be traced by the occurrence of secondary U minerals (e.g. kasolite and uranophane), Th/U ratios ≤ 0.1, and the weak correlation between Th/K and U/K (e.g. r = 0.39 and − 0.11).</p></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"24 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10580569/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41234591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Eu(III) and Am(III) adsorption on aluminum (hydr)oxide minerals: surface complexation modeling","authors":"Anshuman Satpathy,&nbsp;Amy E. Hixon","doi":"10.1186/s12932-023-00081-5","DOIUrl":"10.1186/s12932-023-00081-5","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Americium is a highly radioactive actinide element found in used nuclear fuel. Its adsorption on aluminum (hydr)oxide minerals is important to study for at least two reasons: (i) aluminum (hydr)oxide minerals are ubiquitous in the subsurface environment and (ii) bentonite clays, which are proposed engineered barriers for the geologic disposal of used nuclear fuel, have the same ≡AlOH sites as aluminum (hydr)oxide minerals. Surface complexation modeling is widely used to interpret the adsorption behavior of heavy metals on mineral surfaces. While americium sorption is understudied, multiple adsorption studies for europium, a chemical analog, are available. In this study we compiled data describing Eu(III) adsorption on three aluminum (hydr)oxide minerals—corundum (α-Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;), γ-alumina (γ-Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;) and gibbsite (γ-Al(OH)&lt;sub&gt;3&lt;/sub&gt;)—and developed surface complexation models for Eu(III) adsorption on these minerals by employing diffuse double layer (DDL) and charge distribution multisite complexation (CD-MUSIC) electrostatic frameworks. We also developed surface complexation models for Am(III) adsorption on corundum (α-Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;) and γ-alumina (γ-Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;) by employing a limited number of Am(III) adsorption data sourced from literature. For corundum and γ-alumina, two different adsorbed Eu(III) species, one each for strong and weak sites, were found to be important regardless of which electrostatic framework was used. The formation constant of the weak site species was almost 10,000 times weaker than the formation constant for the corresponding strong site species. For gibbsite, two different adsorbed Eu(III) species formed on the single available site type and were important for the DDL model, whereas the best-fit CD-MUSIC model for Eu(III)-gibbsite system required only one Eu(III) surface species. The Am(III)-corundum model based on the CD-MUSIC framework had the same set of surface species as the Eu(III)-corundum model. However, the log K values of the surface reactions were different. The best-fit Am(III)-corundum model based on the DDL framework had only one site type. Both the CD-MUSIC and the DDL model developed for Am(III)-γ-alumina system only comprised of one site type and the formation constant of the corresponding surface species was ~ 500 times stronger and ~ 700 times weaker than the corresponding Eu(III) species on the weak and the strong sites, respectively. The CD-MUSIC model for corundum and both the DDL and the CD-MUSIC models for γ-alumina predicted the Am(III) adsorption data very well, whereas the DDL model for corundum overpredicted the Am(III) adsorption data. The root mean square of errors of the DDL and CD-MUSIC models developed in this study were smaller than those of two previously-published models describing Am(III)-γ-alumina system, indicating the better predictive capacity of our models. Overall, our results suggest that using Eu(III)","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"24 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-023-00081-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4799034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Accelerated mineral bio-carbonation of coarse residue kimberlite material by inoculation with photosynthetic microbial mats","authors":"Thomas Ray Jones,&nbsp;Jordan Poitras,&nbsp;Emma Gagen,&nbsp;David John Paterson,&nbsp;Gordon Southam","doi":"10.1186/s12932-023-00082-4","DOIUrl":"10.1186/s12932-023-00082-4","url":null,"abstract":"<div><p>Microbiological weathering of coarse residue deposit (CRD) kimberlite produced by the Venetia Diamond Mine, Limpopo, South Africa enhanced mineral carbonation relative to untreated material. Cultures of photosynthetically enriched biofilm produced maximal carbonation conditions when mixed with kimberlite and incubated under near surface conditions. Interestingly, mineral carbonation also occurred in the dark, under water-saturated conditions. The examination of mineralized biofilms in ca. 150 µm-thick-sections using light microscopy, X-ray fluorescence microscopy (XFM) and backscatter electron—scanning electron microscopy-energy dispersive x-ray spectrometry demonstrated that microbiological weathering aided in producing secondary calcium/magnesium carbonates on silicate grain boundaries. Calcium/magnesium sulphate(s) precipitated under vadose conditions demonstrating that evaporites formed upon drying. In this system, mineral carbonation was only observed in regions possessing bacteria, preserved within carbonate as cemented microcolonies. 16S rDNA molecular diversity of bacteria in kimberlite and in natural biofilms growing on kimberlite were dominated by Proteobacteria that are active in nitrogen, phosphorus and sulphur cycling. Cyanobacteria based enrichment cultures provided with nitrogen &amp; phosphorus (nutrients) to enhance growth, possessed increased diversity of bacteria, with Proteobacteria re-establishing themselves as the dominant bacterial lineage when incubated under dark, vadose conditions consistent with natural kimberlite. Overall, 16S rDNA analyses revealed that weathered kimberlite hosts a diverse microbiome consistent with soils, metal cycling and hydrocarbon degradation. Enhanced weathering and carbonate-cemented microcolonies demonstrate that microorganisms are key to mineral carbonation of kimberlite.</p></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"24 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-023-00082-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4650137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Ni2+, Zn2+, and Co2+ on green rust transformation to magnetite","authors":"Orion Farr,&nbsp;Evert J. Elzinga,&nbsp;Nathan Yee","doi":"10.1186/s12932-022-00080-y","DOIUrl":"10.1186/s12932-022-00080-y","url":null,"abstract":"<div><p>In this study, we investigated Ni²⁺, Zn²⁺, and Co²⁺ mineralogical incorporation and its effect on green rust transformation to magnetite. Mineral transformation experiments were conducted by heating green rust suspensions at 85 °C in the presence of Ni²⁺, Zn²⁺, or Co²⁺ under strict anoxic conditions. Transmission electron microscopy and powder X-ray diffraction showed the conversion of hexagonal green rust platelets to fine grained cubic magnetite crystals. The addition of Ni²⁺, Zn²⁺, and Co²⁺ resulted in faster rates of mineral transformation. The conversion of green rust to magnetite was concurrent to significant increases in metal uptake, demonstrating a strong affinity for metal sorption/co-precipitation by magnetite. Dissolution ratio curves showed that Ni²⁺, Zn²⁺, and Co²⁺ cations were incorporated into the mineral structure during magnetite crystal growth. The results indicate that the transformation of green rust to magnetite is accelerated by metal impurities, and that magnetite is a highly effective scavenger of trace metals during mineral transformation. The implications for using diagenetic magnetite from green rust precursors as paleo-proxies of Precambrian ocean chemistry are discussed.</p><h3>Graphical Abstract</h3>\u0000 <div><figure><div><div><picture><source><img></source></picture></div></div></figure></div>\u0000 </div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"23 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9798576/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10511929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemistry and microbiology of tropical serpentine soils in the Santa Elena Ophiolite, a landscape-biogeographical approach","authors":"Agustín F. Solano-Arguedas,&nbsp;Christopher Boothman,&nbsp;Laura Newsome,&nbsp;Richard A. D. Pattrick,&nbsp;Daniel Arguedas-Quesada,&nbsp;Clare H. Robinson,&nbsp;Jonathan R. Lloyd","doi":"10.1186/s12932-022-00079-5","DOIUrl":"10.1186/s12932-022-00079-5","url":null,"abstract":"<div><p>The Santa Elena Ophiolite is a well-studied ultramafic system in Costa Rica mainly comprised of peridotites. Here, tropical climatic conditions promote active laterite formation processes, but the biogeochemistry of the resulting serpentine soils is still poorly understood. The aim of this study was to characterize the soil geochemical composition and microbial community of contrasting landscapes in the area, as the foundation to start exploring the biogeochemistry of metals occurring there. The soils were confirmed as Ni-rich serpentine soils but differed depending on their geographical location within the ophiolite area, showing three serpentine soil types. Weathering processes resulted in <i>mountain</i> soils rich in trace metals such as cobalt, manganese and nickel. The lowlands showed geochemical variations despite sharing similar landscapes: the <i>inner ophiolite lowland</i> soils were more like the surrounding mountain soils rather than the <i>north lowland</i> soils at the border of the ophiolite area, and within the same riparian basin, concentrations of trace metals were higher downstream towards the mangrove area. Microbial community composition reflected the differences in geochemical composition of soils and revealed potential geomicrobiological inputs to local metal biogeochemistry: iron redox cycling bacteria were more abundant in the mountain soils, while more manganese-oxidizing bacteria were found in the lowlands, with the highest relative abundance in the mangrove areas. The fundamental ecological associations recorded in the serpentine soils of the Santa Elena Peninsula, and its potential as a serpentinization endemism hotspot, demonstrate that is a model site to study the biogeochemistry, geomicrobiology and ecology of tropical serpentine areas.</p><h3>Graphical Abstract</h3>\u0000 <div><figure><div><div><picture><source><img></source></picture></div></div></figure></div>\u0000 </div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"23 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9516835/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40378575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved volume variable cluster model method for crystal-lattice optimization: effect on isotope fractionation factor","authors":"Yan-Fang Wang,&nbsp;Xin-Yue Ji,&nbsp;Le-Cai Xing,&nbsp;Peng-Dong Wang,&nbsp;Jian Liu,&nbsp;Tian-Di Zhang,&nbsp;Hao-Nan Zhao,&nbsp;Hong-Tao He","doi":"10.1186/s12932-022-00078-6","DOIUrl":"10.1186/s12932-022-00078-6","url":null,"abstract":"<div><p>The isotopic fractionation factor and element partition coefficient can be calculated only after the geometric optimization of the molecular clusters is completed. Optimization directly affects the accuracy of some parameters, such as the average bond length, molecular volume, harmonic vibrational frequency, and other thermodynamic parameters. Here, we used the improved volume variable cluster model (VVCM) method to optimize the molecular clusters of a typical oxide, quartz. We documented the average bond length and relative volume change. Finally, we extracted the harmonic vibrational frequencies and calculated the equilibrium fractionation factor of the silicon and oxygen isotopes. Given its performance in geometrical optimization and isotope fractionation factor calculation, we further applied the improved VVCM method to calculate isotope equilibrium fractionation factors of Cd and Zn between the hydroxide (Zn–Al layered double hydroxide), carbonate (cadmium-containing calcite) and their aqueous solutions under superficial conditions. We summarized a detailed procedure and used it to re-evaluate published theoretical results for cadmium-containing hydroxyapatite, emphasizing the relative volume change for all clusters and confirming the optimal point charge arrangement (PCA). The results showed that the average bond length and isotope fractionation factor are consistent with those published in previous studies, and the relative volume changes are considerably lower than the results calculated using the periodic boundary method. Specifically, the average Si–O bond length of quartz was 1.63 Å, and the relative volume change of quartz centered on silicon atoms was  − 0.39%. The average Zn–O bond length in the Zn–Al-layered double hydroxide was 2.10 Å, with a relative volume change of 1.96%. Cadmium-containing calcite had an average Cd–O bond length of 2.28 Å, with a relative volume change of 0.45%. At 298 K, the equilibrium fractionation factors between quartz, Zn–Al-layered double hydroxide, cadmium-containing calcite, and their corresponding aqueous solutions were <span>(Delta ^{30/28} {text{Si}}_{{{text{Qtz-H}}_{4} {text{SiO}}_{4} }} = 2.20{permil} )</span>, <span>(Delta^{18/16} {text{O}}_{ {text{Qtz}}{-} ( {text{H}}_{2} {text{O}} )_{text{n}}} = 36.05{permil})</span>, <span>(Delta^{66/64} {text{Zn}}_{ {text{Zn}} {-} {text{Al LDH-Zn}} ( {text{H}}_{2} {text{O}} )_{text{n}}^{2+}} = 1.12{permil})</span> and <span>(Delta^{114/110} {text{Cd}}_{ {text{(Cd--Cal)-Cd}} ( {text{H}}_{2} {text{O}} )_ {text{n}}^{2 +} } = - 0.26{permil})</span> respectively. These results strongly support the reliability of the improved VVCM method for geometric optimization of molecular clusters.</p></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"23 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-022-00078-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4868609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A single column separation method for barium isotope analysis of geologic and hydrologic materials with complex matrices","authors":"R. M. Matecha,&nbsp;R. C. Capo,&nbsp;B. W. Stewart,&nbsp;R. L. Thompson,&nbsp;J. A. Hakala","doi":"10.1186/s12932-021-00077-z","DOIUrl":"10.1186/s12932-021-00077-z","url":null,"abstract":"<div><p>The increasing significance of barium (Ba) in environmental and geologic research in recent years has led to interest in the application of the Ba isotopic composition as a tracer for natural materials with complex matrices. Most Ba isotope measurement techniques require separation of Ba from the rest of sample prior to analysis. This paper presents a method using readily available materials and disposable columns that effectively separates Ba from a range of geologic and hydrologic materials, including carbonate minerals, silicate rocks, barite, river water, and fluids with high total dissolved solids and organic content such as oil and gas brines, rapidly and without need for an additional cleanup column. The technique involves off-the-shelf columns and cation exchange resin and a two-reagent elution that uses 2.5 N HCl followed by addition of 2.0 N HNO₃. We present data to show that major matrix elements from almost any natural material are separated from Ba in a single column pass, and that the method also effectively reduces or eliminates isobaric interferences from lanthanum and cerium.</p>\u0000 <div><figure><div><div><picture><source><img></source></picture></div></div></figure></div>\u0000 </div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"22 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8359043/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39302685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}