Aquatic Geochemistry最新文献

{"title":"Upwelling of Deep-seated Fluid in the Sikhote-Alin Region, Far East of the Eurasian Plate","authors":"Hitomi Nakamura,&nbsp;Hikaru Iwamori,&nbsp;Noritoshi Morikawa,&nbsp;Natalia Kharitonova,&nbsp;Georgy Chelnokov,&nbsp;Ivan Bragin,&nbsp;Qing Chang","doi":"10.1007/s10498-021-09398-y","DOIUrl":"10.1007/s10498-021-09398-y","url":null,"abstract":"<div><p>Spring waters with high-pCO₂ content are widely distributed in the Sikhote-Alin region in Russia. Mukhen spa is one such spring located in the northern Sikhote-Alin region. This spa has two types of upwelling spring waters and exhibits distinct chemical signatures. One of the springs originates from a shallow aquifer and features hydrogen and oxygen isotopic ratios of meteoric water with a high ³He/⁴He ratio, whereas the other originates from a deeper aquifer and features a distinctly negative δ¹⁸O with a lower ³He/⁴He ratio. To understand this apparent discrepancy and the water circulation dynamics beneath Mukhen springs, we utilized all published data concerning the major solute elements and isotopic ratios of Mukhen spring waters and compared them with the He isotopic compositions on several springs in the far eastern region, which are newly analyzed in this study. The results show that the shallow aquifer comprises meteoric water that interacts with the crust enhanced by the gas component welling up from deep underground, while the fluid in deep aquifer fingerprinted the hydration reaction of silicate and involves a mantle component possibly delivered by a deep-seated fluid and/or gas upwelling along the tectonic fault through the western margin of the Sikhote-Alin region.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 4","pages":"269 - 282"},"PeriodicalIF":1.6,"publicationDate":"2021-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10498-021-09398-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4407390","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":"Carbonate Alkalinity Enhances Triclosan Photolysis","authors":"Katie A. Albanese,&nbsp;Mrinal Chakraborty,&nbsp;Christopher M. Hadad,&nbsp;Yu-Ping Chin","doi":"10.1007/s10498-021-09397-z","DOIUrl":"10.1007/s10498-021-09397-z","url":null,"abstract":"<div><p>Triclosan (TCS) is an antimicrobial compound found in many household products used across the world. TCS is not completely removed in wastewater systems, resulting in trace-level concentrations present ubiquitously in surface waters. The direct photodegradation of TCS has been widely studied, with results indicating that TCS breaks down to chlorophenols and dioxins. To date, no studies have specifically investigated the effects of alkalinity on the photolysis of the acidic form of TCS. This study assessed the effect of carbonate/bicarbonate alkalinity, which is ubiquitous in natural waters, on the photolysis rate of TCS. Results indicate that bicarbonate enhances the photodegradation of TCS at pH values well below the p<i>K</i>_a of TCS (7.9), with direct photolysis reaction kinetics that are very slow in the absence of buffers, but significant in the presence of bicarbonate (0.711 h⁻¹ at pH 6.55). At pH values well above its p<i>K</i>_a, both unbuffered- and buffered-mediated photolysis increased dramatically (1.92 h⁻¹ for direct photolysis and 2.86 h⁻¹ in buffered water) and is attributable to the increased photoreactivity of TCS by its conjugate base. Photolysis of methyl triclosan (MeTCS), a non-acidic analog of TCS, demonstrated the importance of TCS’s acidic functionality as MeTCS did not degrade at any pH. The observed influence of alkalinity on the acidic form of TCS photolysis was attributed to both a decrease in its excited state p<i>K</i>_a, coupled with TCS deprotonation through an excited state proton transfer to a base (bicarbonate and to a lesser degree hydrogen phosphate) resulting in the more photo-labile conjugate base form of TCS.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 3","pages":"159 - 171"},"PeriodicalIF":1.6,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10498-021-09397-z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4252103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Abiotic Nitrite Oxidation by Ligand-Bound Manganese (III): The Chemical Mechanism","authors":"George W. Luther III,&nbsp;Jennifer S. Karolewski,&nbsp;Kevin M. Sutherland,&nbsp;Colleen M. Hansel,&nbsp;Scott D. Wankel","doi":"10.1007/s10498-021-09396-0","DOIUrl":"10.1007/s10498-021-09396-0","url":null,"abstract":"<div><p>Given their environmental abundances, it has been long hypothesized that geochemical interactions between reactive forms of manganese and nitrogen may play important roles in the cycling of these elements. Indeed, recent studies have begun shedding light on the possible role of soluble, ligand-bound Mn(III) in promoting abiotic transformations under environmentally relevant conditions. Here, using the kinetic data of Karolewski et al. (Geochim Cosmochim Acta 293:365–378, 2021), we provide the chemical mechanism for the abiotic oxidation of nitrite (NO₂⁻) by Mn(III)-pyrophosphate, Mn^IIIPP, to form nitrate (NO₃⁻). Nitrous acid (HNO₂), not NO₂⁻, is the reductant in the reaction, based on thermodynamic and kinetic considerations. As soluble Mn(III) complexes react in a one-electron transfer reaction, two one-electron transfer steps must occur. In step one, HNO₂ is first oxidized to nitrogen dioxide, ·NO₂, a free radical via a hydrogen atom transfer (HAT) reaction. We show that this inner sphere reaction process is the rate-limiting step in the reaction sequence. In step two, ·NO₂ reacts with a second Mn^IIIPP complex to form the nitronium ion (NO₂⁺), which is isoelectronic with CO₂. Unlike the poor electron-accepting capability of CO₂, NO₂⁺ is an excellent electron acceptor for both OH⁻ and H₂O, so NO₂⁺ reacts quickly with water to form the end-product NO₃⁻ (step 3 in the reaction sequence). Thus, water provides the O atom in this nitrification reaction in accordance with the O-isotope data. This work provides mechanistic perspective on a potentially important interaction between Mn and nitrogen species, thereby offering a framework in which to interpret kinetic and isotopic data and to further investigate the relevance of this reaction under environmental conditions.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 3","pages":"207 - 220"},"PeriodicalIF":1.6,"publicationDate":"2021-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10498-021-09396-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5185219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 and carbon dioxide consumption in a small tropical river catchment, southwestern India","authors":"Baby Krishnan Nisha,&nbsp;Keshava Balakrishna,&nbsp;Harikripa Narayana Udayashankar,&nbsp;Busnur Rachotappa Manjunatha","doi":"10.1007/s10498-021-09394-2","DOIUrl":"10.1007/s10498-021-09394-2","url":null,"abstract":"<div><p>Studies done on small tropical west-flowing river catchments located in the Western Ghats in southwestern India have suggested very intense chemical weathering rates and associated CO₂ consumption. Very less studies are reported from these catchments notwithstanding their importance as potential sinks of atmospheric CO₂ at the global scale. A total of 156 samples were collected from a small river catchment in the southwestern India, the Payaswini–Chandragiri river Basin, during pre-monsoon, monsoon and post-monsoon seasons in 2016 and 2017, respectively. This river system comprises two small rivers originating at an elevation of 1350 m in the Western Ghats in peninsular India. The catchment area is dominated by biotite sillimanite gneiss. Sodium is the dominant cation, contributing ~ 50% of the total cations, whereas HCO₃⁻ contributes ~ 75% of total anions. The average anion concentration in the samples varied in the range HCO₃⁻ &gt; Cl⁻ &gt; SO₄²⁻ &gt; NO₃⁻ &gt; F⁻, whereas major cation concentration varied in the range Na⁺  &gt; Ca²⁺  &gt; Mg²⁺  &gt; K⁺. The average silicate weathering rate (SWR) was 42 t km⁻² y⁻¹ in the year 2016 and 36 t km⁻² y⁻¹ in 2017. The average annual carbon dioxide consumption rate (CCR) due to silicate rock weathering was 9.6 × 10⁵ mol km⁻²y⁻¹ and 8.3 × 10⁵ mol km⁻² y⁻¹ for 2016 and 2017, respectively. The CCR in the study area is higher than other large tropical river catchments like Amazon, Congo-Zaire, Orinoco, Parana and Indus because of its unique topography, hot and humid climate and intense rainfall.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 3","pages":"173 - 206"},"PeriodicalIF":1.6,"publicationDate":"2021-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10498-021-09394-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5518241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contribution of Hydrothermal Processes to the Enrichment of Lithium in Brines: Evidence from Water–Rock Interacting Experiments","authors":"Xueyin Yuan,&nbsp;Yufei Hu,&nbsp;Yanjun Zhao,&nbsp;Qiang Li,&nbsp;Chenglin liu","doi":"10.1007/s10498-021-09395-1","DOIUrl":"10.1007/s10498-021-09395-1","url":null,"abstract":"<div><p>Over the world, the available lithium (Li) resources are reserved mainly in closed-basin brines, with high Li concentration (&gt; 150 mg/L) and low Mg/Li ratio (&lt; 10) being critical for Li extraction using precipitation-based methods. In order to investigate the enrichment of Li over Mg during the formation of Li brine deposits, batch water–rock interacting experiments between igneous rocks and aqueous solutions were carried out under low (25, 50 and 75 °C) and high (200, 300 and 400 °C) temperature conditions. Our results show that for the experiments using water and accomplished under 25 °C, the Mg and Li concentrations vary from 0.470 and 0.782 mg/L in the solution interacted with Li-rich granite, to 5.626 and &lt; 0.002 mg/L in that interacted with basalt, with Mg/Li ratio being slightly higher than those of the igneous rocks. By contrast, while a NaCl or Na₂SO₄ solution was used, the Mg and Li concentrations can be improved by up to tens of times, and the Mg/Li ratio also increased slightly. Lastly and above all, with increase in the water–rock interacting temperature from 25 to 400 °C, the Mg and Li concentrations in all solutions vary conversely and the Mg/Li ratio decreases by orders of magnitude, leading to the formation of Li-rich brines with very low Mg/Li ratios at temperatures above 200 °C. By comparing the results from our experiment to those from Li-rich springs, rivers and closed-basin brines, we conclude that water evaporation over time is fundamental for the concentration of Li in brines, meanwhile high-temperature hydrothermal processes are key to the formation of Li brine deposits with low Mg/Li ratios.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 3","pages":"221 - 239"},"PeriodicalIF":1.6,"publicationDate":"2021-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10498-021-09395-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4778173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metal Speciation in Water of the Flooded Mine “Arsenic” (Karelia, Russia): Equilibrium-Kinetic Modeling with a Focus on the Influence of Humic Substances","authors":"Elena V. Cherkasova,&nbsp;Artem A. Konyshev,&nbsp;Evgeniya A. Soldatova,&nbsp;Evgeniya S. Sidkina,&nbsp;Mikhail V. Mironenko","doi":"10.1007/s10498-021-09393-3","DOIUrl":"10.1007/s10498-021-09393-3","url":null,"abstract":"<div><p>Equilibrium-kinetic modeling allows investigating metal behavior in the water–rock-organic matter system with time to evaluate anthropogenic effects on the environment. In the article, the interactions of stagnant mine drainage water of the flooded mine “Arsenic” with ore and gangue minerals were simulated using different organic matter incorporation approaches. If the model is closed to humic substances (no additional organic matter input), most fulvic acids are bound in the Fe fulvate complex. While under the removal of Fe fulvate from the model, the Cu fulvate becomes prevalent, the contribution of the fulvate complexes with Zn, Mg, and Ca also increases. This scenario simulates the organo-mineral complexes behavior well and allows identifying the sequence of metal binding to organic ligands as follows Fe &gt; Cu &gt; Zn &gt; Mg &gt; Ca. The second scenario imitates the constant input of organic matter to the model (open system regarding humic substances). The dissolved metal concentrations in the model solution are extremely high in comparison to the mine drainage water. This scenario demonstrates that excessive input of organic matter leads to the accumulation of the metals in a dissolved form and blocks the secondary mineral formation despite the faster dissolution of the primary minerals under a more acidic pH than in the first scenario. However, despite the differences between the model solution and the mine drainage water, this scenario is useful to address specific issues associated with changes in natural and anthropogenic conditions. Both scenarios show the importance of organic matter incorporation to the equilibrium-kinetic models.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 2","pages":"141 - 158"},"PeriodicalIF":1.6,"publicationDate":"2021-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10498-021-09393-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4714454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Free Eu(III) Determination by Donnan Membrane Technique with Electrochemical Detection: Implementation and Evaluation","authors":"Noémie Janot,&nbsp;Jan E. Groenenberg,&nbsp;Alba Otero-Fariña,&nbsp;José Paulo Pinheiro","doi":"10.1007/s10498-021-09392-4","DOIUrl":"10.1007/s10498-021-09392-4","url":null,"abstract":"<div><p>The aim of this study was to develop an analytical method to determine free concentrations of Europium (Eu(III)) in natural waters. Europium(III) in solution was detected using cathodic stripping voltammetry after complexation with <i>N</i>-nitroso-<i>N</i>-phenylhydroxylamine (cupferron). Optimization of analytical parameters allowed us to detect nanomolar levels of Eu(III) in solution. Free Eu(III) in solution was measured using the Donnan membrane technique in which a natural solution (the “donor”, containing various ligands) is separated from a ligand-free solution (the “acceptor”) by a cation-exchange membrane. This membrane allows only non-colloidal cationic species to pass through it, and after an adequate time equilibrium is reached between both compartments. Total Eu(III) concentration can then be quantified in the acceptor solution and related to free Eu(III) in the natural sample. Due to its high valency, free Eu(III) tends to adsorb strongly to the cation-exchange membrane. In order to determine the physicochemical conditions minimizing this adsorption, we analyzed solutions of different Eu(III) and Ca(II) (as background ion) concentrations. Results showed that 100 mM of Ca(II) were necessary to make adsorption of Eu(III) onto the membrane negligible. The optimized setup was then used to quantify Eu(III) complexation in a Eu(III)-dissolved organic matter solution.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 2","pages":"127 - 140"},"PeriodicalIF":1.6,"publicationDate":"2021-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10498-021-09392-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4675067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Concentration of Iron(II) in Fresh Groundwater Controlled by Siderite, Field Evidence","authors":"C. G. E. M. van Beek,&nbsp;D. G. Cirkel,&nbsp;M. J. de Jonge,&nbsp;N. Hartog","doi":"10.1007/s10498-020-09390-y","DOIUrl":"https://doi.org/10.1007/s10498-020-09390-y","url":null,"abstract":"<p>Iron(II) concentrations in fresh groundwater in Dutch aquifers range from absent up to 50?mg/l. Evaluation of extensive chemical data sets learned that the maximum logarithmic concentration of iron(II) in aquifers, between?±?6.5?&lt;?pH?&lt;??±?8, is a linear function of pH, governed by Siderite. It is a broad relation due to oversaturation with respect to Siderite and to variation in alkalinity. Iron(II) is continuously supplied to groundwater by reduction of hydrous ferric oxides (HFO), until becoming saturated with respect to Siderite, and from then on, HFO reduction and Siderite precipitation occur simultaneously. In Dutch aquifers, the electron supply rate (equivalent to the organic matter oxidation rate) apparently exceeds the HFO electron uptake rate (equivalent to the HFO reduction rate) and the excess supply is taken up by sulfate (equivalent to the sulfate reduction rate): HFO reduction, sulfate reduction and FeS precipitation occurring simultaneously, where the presence of Siderite prevents a dip in the iron(II) concentration. After sulfate becomes exhausted, the excess electron supply is transferred to methane production: HFO reduction and methane production occurring simultaneously. This evaluation also demonstrated that the organic matter oxidation rate and the HFO reduction rate decrease over time. The results of this study are also relevant for the behavior of As and of Co, Ni and Zn in groundwater, as HFO, Pyrite and Siderite may contain variable contents of these elements.</p>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 1","pages":"49 - 61"},"PeriodicalIF":1.6,"publicationDate":"2021-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10498-020-09390-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4120119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental and Modeling Studies on Sorption Behaviour of 133Ba(II) on Fe–Montmorillonite Clay Minerals","authors":"Santosh Chikkamath,&nbsp;Madhuri A. Patel,&nbsp;Aishwarya S. Kar,&nbsp;Vaibhavi V. Raut,&nbsp;Bhupendra. S. Tomar,&nbsp;J. Manjanna","doi":"10.1007/s10498-020-09389-5","DOIUrl":"https://doi.org/10.1007/s10498-020-09389-5","url":null,"abstract":"<p>Fe type clay minerals, Fe–montmorillonite, are expected to form in the nuclear waste repositories over a span of few years owing to the interaction of corrosion products from overpack and/or canister with bentonite consisting of montmorillonite (Mt) as the major clay mineral. Therefore, it is important to understand the properties of altered clay minerals, Fe–Mt. In the present study, the sorption behaviour of ¹³³Ba(II), one of the high-yield fission products of uranium-based fuels and analogue of ⁹⁰Sr (<i>t</i>_1/2?=?28.5 y), on Fe(II)–Mt and Fe(III)–Mt has been investigated. Retention behavior of Ba(II) on Fe–Mt has been studied at varying pH (3–9), ionic strength (0.001?M–1?M) and Ba(II) concentration (10^?9–10^?3 M) by batch sorption method. The distribution coefficient (<i>K</i>_d) of Ba(II) on Fe–Mt was found to be nearly independent of pH while it decreased with increasing ionic strength indicating ion exchange as the dominant Ba(II) sorption mode on Fe–Mt. Adsorption isotherm of Ba(II) exhibited linearity in the entire Ba(II) concentration range. A comparison of Ba(II) sorption behavior on Fe–Mt and Na–Mt has been made. The Fe released from both Fe(III)–Mt and Fe(II)–Mt was measured in all the sorption experiments and was found to be much less in the case of Fe(III)–Mt (≤?1.7?ppm) when compared to Fe(II)–Mt (~?25?ppm). The modeling of Ba(II) sorption profiles on Fe–Mt and Na–Mt has been carried out using FITEQL 4.0.</p>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 1","pages":"31 - 47"},"PeriodicalIF":1.6,"publicationDate":"2020-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10498-020-09389-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4481781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Climate Change-Induced Changes in the Chemistry of a High-Altitude Mountain Lake in the Central Alps","authors":"Sandra M. Steingruber,&nbsp;Stefano M. Bernasconi,&nbsp;Giorgio Valenti","doi":"10.1007/s10498-020-09388-6","DOIUrl":"10.1007/s10498-020-09388-6","url":null,"abstract":"<div><p>Mountains are among the most sensitive ecosystems to climate change, and one of the most evident signs of climate-related effect is the continuous net loss of ice from the cryosphere. Several studies showed that meltwater from glaciated and perennially frozen areas can profoundly affect alpine aquatic ecosystems. Here, we present the impressive temporal increase in solutes in Lake Leit, a mountain lake in the Central Alps that is impacted by an active rock glacier. During the last 30 years, concentrations of sulfate and base cations increased by factors of 4 and 3, respectively. Atmospheric deposition, the only catchment external source, could be excluded as possible cause. The inlets have sulfate and base cations concentrations that were up to double the concentrations of the lake outlet confirming the presence of catchment internal sources. The highest concentrations were measured in the springs at the bottom of the rock glacier. Ground surface temperatures of the rock glacier indicated a high probability of permafrost occurrence, while the annual mean air temperature after the mid-1980s showed continuously positive deviations from the long-term average values (period 1961–1990) with increasing values after 2010. δ³⁴S of sulfate in the inlets and the outflow indicated that sulfate in Lake Leit mainly derived from dissolution of gypsum/anhydrite even if its presence is not confirmed by the Geologic Atlas of Switzerland. Because of these results, we postulate the presence of subsurface traces of sulfate-bearing evaporites, probably associated with Triassic metasediments. These deposits are very common in the closer surroundings. We further hypothesize that the thawing of permafrost affects the flow path of water enabling its contact with fresh highly weatherable minerals increasing the overall weathering rate and shifting the relative ionic composition in the discharge toward the ions that originate from the most soluble minerals. This study shows that increased permafrost thawing in the future can influence water quality in high-alpine settings.</p></div>","PeriodicalId":8102,"journal":{"name":"Aquatic Geochemistry","volume":"27 2","pages":"105 - 126"},"PeriodicalIF":1.6,"publicationDate":"2020-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10498-020-09388-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4711122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}