Applied Geochemistry最新文献

{"title":"The precipitation mechanisms of scheelite from CO2-rich hydrothermal fluids: Insight from thermodynamic modeling","authors":"Hao Liu ,&nbsp;Xiang-Chong Liu ,&nbsp;De-Hui Zhang ,&nbsp;Zhen-Ju Zhou ,&nbsp;Feng-Bin Han","doi":"10.1016/j.apgeochem.2024.106187","DOIUrl":"10.1016/j.apgeochem.2024.106187","url":null,"abstract":"<div><div>Scheelite and wolframite are two main tungsten-bearing ore minerals in tungsten deposits. Compared to wolframite formed mostly by NaCl–H₂O fluids, scheelite in many but not all tungsten deposits is associated with CO₂–bearing hydrothermal fluids, but its precipitation mechanisms from these fluids are poorly understood. The replacement of wolframite by scheelite is common among tungsten deposits where these two tungstates coexist, but how CO₂, as the pH-buffering agent, affects their replacement remains unclear. To answer these questions, we first tested the pH-buffering effect of CO₂ by comparing available experimental pH values of H₂O–CO₂±NaCl solutions at 200–280 °C and the corresponding thermodynamic modeling results. The mean absolute errors between the calculated and experimental pH values are 0.14 log units in H₂O–CO₂ solutions and 0.13 log units in H₂O–CO₂–NaCl solutions, indicating that the calculated acitivities of H⁺ in CO₂-bearing solutions are reliable. Then, the solubilities of scheelite, scheelite-ferberite, and scheelite-hübnerite in NaCl–H₂O–CO₂ systems were modeled in this study. Our modeling results suggest that scheelite solubility in CO₂-rich fluids is highly dependent on fluid pressure but is insensitive to fluid temperature. A decrease in fluid pressure from lithostatic to hydrostatic levels at a depth of 3–8 km causes CO₂ escape and pH rise and precipitates over 70 % of tungsten contents in fluids on average. Therefore, CO₂ escape is an efficient mechanism for precipitating scheelite from CO₂–rich hydrothermal fluids. The independence of scheelite solubility on temperature at high pressures and the slightly retrograde solubility at low pressures allows CO₂–rich hydrothermal fluids to carry a great amount of tungsten far away from its sources. This may be one of reasons why some scheelite deposits occur at greater distances (&gt;500 m) from the granite or extend along its strike for several kilometers. Similar to the cases in NaCl–H₂O systems, two mechanisms for scheelite replacing wolframite in CO₂–rich fluids are identified, a single decrease in fluid pressure or simple cooling plus an increase in the ratios of total Ca contents to total Fe (or Mn) contents in fluids.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"175 ","pages":"Article 106187"},"PeriodicalIF":3.1,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142416493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stable isotopic evidence of cadmium enrichment in soils of black shale distribution areas","authors":"Wanfu Zhao ,&nbsp;Yinxian Song ,&nbsp;Wei Li ,&nbsp;Dongxing Guan ,&nbsp;Tao Li ,&nbsp;Chao Guo ,&nbsp;Ning Wei ,&nbsp;Junfeng Ji","doi":"10.1016/j.apgeochem.2024.106185","DOIUrl":"10.1016/j.apgeochem.2024.106185","url":null,"abstract":"<div><div>Black shale-derived soils exhibit significant heavy metal enrichment, notably cadmium (Cd) enrichment. This study pioneered the reporting of δ¹¹⁴/¹¹⁰Cd isotopic values within a black shale-soil system, offering novel insights into the geochemical behaviors and enrichment mechanisms of Cd during soil formation processes influenced by weathering. Systematic rock‒soil sampling was conducted on the lower Cambrian Hetang Formation in western Zhejiang, China, which is characterized by Cd-rich black shale. Employing analytical methods, including principal component analysis and multiple linear regression, we investigated the factors influencing heavy metal content in soil, such as element dissolution during weathering, soil pH, and the presence of iron-manganese oxides, sulfides, organic matter, and clay minerals. Our findings revealed a compositional range of δ¹¹⁴/¹¹⁰Cd in black shale (1.93‰–3.31‰) contrasting with that in adjacent soils (0.31‰–1.82‰), illustrating significant Cd isotopic fractionation during weathering, where heavier Cd isotopes are preferentially leached, and lighter isotopes are enriched in the soil in association with iron-manganese oxides. This research not only deepens the understanding of Cd enrichment mechanisms within the rock‒soil system against a black shale geological background but also elucidates the formation processes of soil Cd pollution in areas with a high geochemical background.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"175 ","pages":"Article 106185"},"PeriodicalIF":3.1,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Removal of Pb2+ and Cu2+ from artificial geothermal brine by zeolite at various salinity and temperature conditions","authors":"Elvira Feldbusch ,&nbsp;Jörg Zotzmann ,&nbsp;Vladimir Roddatis ,&nbsp;Knud Dideriksen ,&nbsp;Roberts Blukis ,&nbsp;Anja Schleicher ,&nbsp;Simona Regenspurg","doi":"10.1016/j.apgeochem.2024.106157","DOIUrl":"10.1016/j.apgeochem.2024.106157","url":null,"abstract":"<div><div>Natural zeolite (predominantly clinoptilolite - Ca) was tested for application in geothermal facilities to remove copper (Cu²⁺) and lead (Pb²⁺) from formation fluids. Batch and dynamic flow-through (only for lead ions) experiments were performed at different salinities (<em>I</em> = 0.1 and 1 mol/L) in NaCl or CaCl₂ solutions at up to 115 °C (batch experiments) and up to 130 °C (flow-through experiments), respectively. The batch experiments resulted in an uptake of up to 24 % at an initial concentration of 0.3 g/L and up to 93 % at 0.03 g/L of Pb²⁺ and 115 °C. For Cu²⁺, the uptake reached 100 % from initial 0.004 g/L. The presence of CaCl₂ in the solution matrix reduced the uptake of the heavy metals as compared to the NaCl matrix. The Pb²⁺ uptake by zeolite granulates at dynamic flow-through conditions at 130 °C was 52 % of the initial value of 20.7 mg/L during the 180 min experimental time. Based on the results from batch experiments the data fitting indicated a site density of monovalent exchange sites of 3.0 ± 2.6 mmol/g solid and a cation exchange capacity (CEC) of 295 ± 26 meq/100 g zeolite. The Pb²⁺ uptake process by zeolite gave a K_D value of log K = 1.53. These calculations were not possible for Cu²⁺ uptake indicating that the uptake mechanisms of Cu²⁺ at high salinities are too complex to be simulated.</div><div>To explain the uptake processes at given conditions various structural analysis were performed. Infrared spectroscopy indicated a cation exchange of lighter ions in the crystal structure of zeolite by the heavier ions Cu²⁺ and Pb²⁺ at 650 to 750 cm⁻¹. After the treatment with heavy metals, two new bands were detected at 2902 and 2982 cm⁻¹, which were not observed in the natural zeolite. With X-ray diffraction (XRD) new crystalline phases were detected in the treated zeolite samples that could be attributed in case of Pb²⁺ uptake to cottunite (PbCl₂) and laurionite (PbOHCl) and in the case of Cu²⁺ uptake to Cu₂Cl(OH)₃ and CuCl₂. The simulated G(r)s supported these observations regarding Pb²⁺ uptake. Using electron microscopy methods, both mechanisms (ion exchange and mineral precipitation) were confirmed: the formation of new Pb²⁺ and Cu²⁺ containing mineral phases on the surface of the zeolite granules and the uniform distribution of chloro-coordinated complexes of Cu²⁺ and Pb²⁺ on the pore surfaces inside the zeolite.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"175 ","pages":"Article 106157"},"PeriodicalIF":3.1,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142416488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Adsorption of Se(IV) on kaolinite and montmorillonite in the presence of fulvic acid","authors":"Hyeonjin Eun ,&nbsp;Seungmo Yeon ,&nbsp;Seonggyu Choi ,&nbsp;Seokjoo Yoon ,&nbsp;Jong-Il Yun","doi":"10.1016/j.apgeochem.2024.106181","DOIUrl":"10.1016/j.apgeochem.2024.106181","url":null,"abstract":"<div><div>This study investigates the influence of fulvic acid, a representative of aquatic natural organic matter (NOM), on the pH-dependent adsorption of Se(IV) on kaolinite and montmorillonite. Given their negative charges in aqueous solutions, Se(IV) and fulvic acid compete for the limited and identical adsorptive sites of clay minerals, particularly in neutral to alkaline environments. This competition was most pronounced under acidic conditions, where both Se(IV) and fulvic acid adsorption are favored. At pH 3, the presence of 20–80 mg·L⁻¹ fulvic acid reduced the Se(IV) adsorption by up to half on both clay adsorbents. However, in near-neutral to alkaline pH regions (pH 6 to 10), the competitive interaction between Se(IV) and fulvic acid was less pronounced, since the adsorption of both fulvic acid and Se(IV) decreased. In particular for kaolinite, a rise in Se(IV) adsorption was evident at lower fulvic acid concentrations (20 mg·L⁻¹). This phenomenon arises from the absence of aqueous complexes between Se(IV) and fulvic acid under acidic conditions, contrasting with their strong interaction under alkaline conditions as observed in the ATR-FTIR spectra. This study sheds light on the influence of NOM on the mobility of Se(IV) in natural waters, an aspect yet to be thoroughly explored.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"175 ","pages":"Article 106181"},"PeriodicalIF":3.1,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical weathering in the Mekong River Basin: Clay mineralogy and element geochemistry of lower-reach river sediments","authors":"Pham Nhu Sang ,&nbsp;Zhifei Liu ,&nbsp;Yulong Zhao ,&nbsp;Pham Trung Hieu ,&nbsp;Sopheak Thav ,&nbsp;Sopheap Den","doi":"10.1016/j.apgeochem.2024.106179","DOIUrl":"10.1016/j.apgeochem.2024.106179","url":null,"abstract":"<div><div>Chemical weathering of parent rocks in river basins plays a significant role in controlling the global geochemical cycle and climate change, especially in the world's largest river basins such as the Mekong River Basin in tropical regions. However, the chemical weathering process of the Mekong River Basin is still not well understood. In this study, clay mineralogy and major/trace-element geochemistry of fluvial sediments (clay, silt, and sand fractions) collected from the lower Mekong River Basin (Cambodia and Vietnam) were utilized to investigate the sediment provenance and chemical weathering process. The major-element compositions of the clay, silt, and sand fraction sediments from both the mainstream and tributaries consist of dominant SiO₂, Al₂O₃, and Fe₂O₃, (84 wt%, 89 wt%, and 95 wt%, respectively) and minor K₂O, Na₂O, MgO, CaO, TiO₂, P₂O₅, and MnO. The clay mineral assemblages in mainstream sediments are high in illite (36 wt%), moderate in kaolinite (28 wt%) and chlorite (26 wt%), and low in smectite (10 wt%), whereas those in tributary sediments are high in smectite (37 wt%), moderate in kaolinite (26 wt%) and chlorite (22 wt%), and low in illite (15 wt%). The different clay mineral assemblages between mainstream and tributary sediments can be significantly related to the parent rock lithology and/or the weathering process in the source region. On the basis of clay mineralogy and elemental geochemistry, river sediments of the mainstream in the lower reach may be derived mainly from felsic rocks in the lower part of the middle reach of this basin, with secondary contributions from the upper and lower reaches as well as the upper part of the middle reach. Sediments in the Kampi and Speu tributaries highly originate from felsic rocks, whereas sediments in the Srepok, Ter, and Chhiong tributaries can be mostly weathering products of mafic rocks. The clay mineral proxies (smectite/(illite + chlorite) and kaolinite/(illite + chlorite)) combined with the elemental geochemistry (CIA, α^AlE values, and weathering trends) of the clay fraction sediments indicate intensive chemical weathering in the lower and middle reaches. The high-relief topography and cold and dry climatic conditions in the upper reach result in high illite and chlorite contents in the soil and moderate chemical weathering. The chemical weathering intensity increases from the upper to middle reaches and further to the lower reach. Tectonics in the middle and upper reaches of the Mekong River Basin play the most important role in controlling weathering and erosion processes, whereas East Asian–Indian monsoon climate conditions with warm temperature and predominant rainfall throughout the year and lithology are the main forcing factors for the intensity of chemical weathering in the lower reach.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"175 ","pages":"Article 106179"},"PeriodicalIF":3.1,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigations of the impact of geothermal water reinjection on water-rock interaction through laboratory experiments and numerical simulations","authors":"Yanyan Huang ,&nbsp;Hongwu Lei ,&nbsp;Jin Na ,&nbsp;Yilong Yuan ,&nbsp;Hailong Tian","doi":"10.1016/j.apgeochem.2024.106180","DOIUrl":"10.1016/j.apgeochem.2024.106180","url":null,"abstract":"<div><div>In the quest for sustainable geothermal energy production, the adoption of geothermal reinjection technology has become a crucial element in the development of geothermal resources. However, the processes of injection and extraction can lead to interactions between water and rock within the geothermal reservoir, resulting in pore blockage. This study focuses on the Kaifeng Zhenyu Garden geothermal field as a case study to examine the water-rock interactions that occur during geothermal reinjection, as well as the subsequent changes in mineral composition and porosity within the reservoir. The findings reveal that the primary minerals undergoing dissolution are dolomite and feldspar, with the precipitation of calcite and clay minerals following suit. Additionally, results from field simulations corroborate that dolomite and feldspar are the main minerals dissolving, accompanied by the precipitation of calcite and illite. Notably, significant changes in mineral dissolution and precipitation near the geothermal well have led to a slight reduction in the reservoir's porosity. This investigation provides valuable insights into the water-rock interactions involved in geothermal reinjection processes across various geothermal fields.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"175 ","pages":"Article 106180"},"PeriodicalIF":3.1,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Origin and composition of dissolved and particulate matter in mountain rivers of the Nepal Himalayas: Insights from Sr and Nd isotopes and elemental ratios","authors":"Rajendra Bhandari ,&nbsp;Kuo-Fang Huang ,&nbsp;Mårten Dario ,&nbsp;Åsa Danielsson ,&nbsp;Subodh Sharma ,&nbsp;Joyanto Routh","doi":"10.1016/j.apgeochem.2024.106183","DOIUrl":"10.1016/j.apgeochem.2024.106183","url":null,"abstract":"<div><div>The Ganga River exhibits elevated concentrations of dissolved strontium (Sr) and a higher radiogenic Sr (⁸⁷Sr/⁸⁶Sr) among global rivers, which impacts oceanic Sr composition. This has implications for understanding weathering and sediment flux into open oceans. The Nepal Himalayan section is a significant part of the upstream Ganga River catchment. We analyzed Sr and Nd isotopes and major element concentrations in water and sediments to trace compositional and seasonal variability in dissolved and particulate matter. The Sr and Nd isotopes, in particular, are crucial in this study as they provide unique signatures that can be used to trace the origin and composition of the dissolved and particulate matter. Representative rivers draining monolithological terrains were selected to investigate the isotopic and elemental provenance and weathering intensity. The elemental ratios (Ca/Na, Mg/Na) indicate the watersheds are carbonate-rich terrains. The Lesser Himalaya (LH) rivers transport radiogenic Sr with high values compared to rivers draining the Tethyan Sedimentary Series (TSS), Higher Himalayan Crystalline (HHC), Mahabharat, and Siwalik Hills. The dry season records a higher ⁸⁷Sr/⁸⁶Sr ratio than the monsoon. Due to the faster dissolution of carbonates compared to silicates, monsoon waters transport less radiogenic Sr. The significant correlation of ⁸⁷Sr/⁸⁶Sr in dissolved and particulate phases signifies that short-term interactions between sediment and water may alter the ⁸⁷Sr/⁸⁶Sr composition. Notably, sediments originating from continental rocks exhibit an inverse correlation between ⁸⁷Sr/⁸⁶Sr and ε_Nd. In conclusion, the Sr and Nd isotopic records in this study categorize the fluvial catchments into geological clusters aligned with the TSS, LH, and Siwaliks, which advance our understanding regarding the provenance besides providing crucial insights into geological processes, weathering, landscape evolution, and sediment flux.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"175 ","pages":"Article 106183"},"PeriodicalIF":3.1,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0883292724002889/pdfft?md5=42180089988e1e40118704d0e487fc39&pid=1-s2.0-S0883292724002889-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Multimethod characterization of geogenic sources of fluoride, arsenic, and uranium in Mexican groundwater","authors":"Cristian Abraham Rivera Armendariz ,&nbsp;Antonio Cardona Benavides ,&nbsp;Eszter Badenszki ,&nbsp;Andre Banning","doi":"10.1016/j.apgeochem.2024.106184","DOIUrl":"10.1016/j.apgeochem.2024.106184","url":null,"abstract":"","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"175 ","pages":"Article 106184"},"PeriodicalIF":3.1,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of major ions and Sr isotopes to indicate the evolution of river water and shallow groundwater chemistry in a typical endorheic watershed, northwestern China","authors":"Nuan Yang ,&nbsp;Liang Guo ,&nbsp;Guangcai Wang ,&nbsp;Luoyao Xiong ,&nbsp;Xinming Song ,&nbsp;Hui Li","doi":"10.1016/j.apgeochem.2024.106182","DOIUrl":"10.1016/j.apgeochem.2024.106182","url":null,"abstract":"<div><div>Studying the hydrochemical evolution of river water and groundwater is vital for comprehending complex regional hydrological cycles and managing water resources. An investigation of hydrochemical evolution mechanism of river water and groundwater was executed in an arid and semi-arid endorheic watershed located in the eastern edge of Qaidam Basin, northwest China, by analyzing major ions and strontium isotopic compositions with the combination of hydrogeochemical methods, PMF model and Pearson correlation analysis. From upstream to downstream, the major ions, ⁸⁷Sr/⁸⁶Sr values and hydrochemical types of river water and groundwater show spatial variations. Major ions and ⁸⁷Sr/⁸⁶Sr analysis reveal that the hydrochmical compositions of river water and groundwater are primarily attributed to silicate weathering, carbonate weathering, evaporite weathering, and agricultural activity. The contribution of four factors affecting the hydrochemical evolution show obvious spatial variations along the flow path. The hydrochemical compositions of river water from the upstream to downstream are mainly contributed by carbonate and silicate weathering as well as weak evaporite weathering (&lt;25%), which are affected by agricultural activity with a great contribution (&gt;25%) in the middle and lower reaches. The contribution to the hydrochemical compositions of groundwater is relatively small (&lt;25%) for carbonate, silicate and evaporite weathering, but great (&gt;25%) for agricultural activity. This study provides implications for understanding the formation and evolution of water and better watershed water management in that typical endorheic watershed basin and even at larger scales.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"175 ","pages":"Article 106182"},"PeriodicalIF":3.1,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enrichment mechanism of groundwater fluoride and its hydrogeological indications in the Badain Jaran Desert, northwest China","authors":"Le Cao ,&nbsp;Zhenlong Nie ,&nbsp;Jianmei Shen ,&nbsp;Zhe Wang ,&nbsp;Zhongshuang Cheng ,&nbsp;Weijia Liu","doi":"10.1016/j.apgeochem.2024.106176","DOIUrl":"10.1016/j.apgeochem.2024.106176","url":null,"abstract":"<div><p>Fluoride (F⁻) enrichment in groundwater poses significant risks to drinking water safety; however, reports of high F⁻ concentrations in groundwater in a vast desert and its hydrogeological indications are limited. In this study, we collected 275 groundwater samples from various depths in the Badain Jaran Desert (BJD) to investigate the distribution characteristics and enrichment mechanisms of F⁻ in desert groundwater, utilizing hydrochemistry, environmental isotopes, and statistical methods. The results indicate that (1) the groundwater F⁻ concentrations in the mountainous areas, desert areas, and downstream wetland areas are 0.10–9.45 mg/L (average of 3.05), 0.19–58.00 mg/L (average of 4.32), and 0.62–9.91 mg/L (average of 1.99), respectively, with corresponding exceedance rates (&gt;1 mg/L) of 83%, 71%, and 80%. (2) In mountainous areas, F⁻ enrichment mechanisms are attributed to ion exchange, evaporative concentration, and the dissolution of fluoride minerals. In desert areas, F⁻ enrichment mechanisms involves multiple hydrogeochemical processes, with the dissolution of fluoride minerals being the most significant, followed by evaporative concentration and desorption. And evaporative concentration is particularly pronounced in shallow groundwater (depth &lt;4 m). In wetland areas, F⁻ enrichment mechanisms are mainly ion exchange and desorption. (3) The F⁻ concentration characteristics (&lt;2 mg/L) and the significant correlation between F⁻ and HCO₃⁻ (R = 0.55, P &lt; 0.01) in the deep groundwater of the desert suggest that groundwater does not originate from deep geothermal sources. (4) Based on the significant differences in groundwater F⁻ concentrations, there is a weak hydrodynamic connection between the groundwater in the Quaternary aquifer and that in the underlying Cretaceous bedrock in desert areas. These findings not only facilitate the safe use of groundwater in desert environments but also provide new insights into the formation, circulation, and evolution of desert groundwater.</p></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"175 ","pages":"Article 106176"},"PeriodicalIF":3.1,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}