Pub Date : 2025-03-13DOI: 10.1016/j.apgeochem.2025.106358
R. Blaine McCleskey , Charles A. Cravotta III , Matthew P. Miller , Tanner W. Chapin , Fred Tillman , Gabrielle L. Keith
Salinity levels in streams and tributaries of the Colorado River Basin have been a major concern for the United States and Mexico for over 50 years as the water is used by millions of people for domestic and industrial purposes. Recently, the United States Geological Survey expanded stream monitoring networks including the number of sites where continuous (15-min) specific conductance is measured in the Colorado River Headwaters and Gunnison River Basin located east of the Colorado-Utah state line (hereafter, UCOL). The purpose of this study is to apply a proxy method to determine salinity and total dissolved solids concentrations from specific conductance and major-ion water type that is applicable to monitoring sites in the UCOL. Within the UCOL, carbonate rich waters originate from high-elevation mountain regions in the eastern UCOL, calcium sulfate rich waters are mainly found in the western half of the UCOL including the Gunnison River Basin, and waters of variable composition are found along the lower reaches of the Colorado River and Eagle River. It was found that the chemistry of sites with variable composition changes seasonally and is impacted by both geogenic and anthropogenic processes, potentially including seasonal application of deicing road salt. The specific conductance – water type proxy can be used to reliably (±10 %) predict salinity and total dissolved solids at 66 monitoring sites in the UCOL. The method is rapid, can generate high-resolution measurements, is cost-effective, and greatly expands the utility of specific conductance measurements. Furthermore, the high-resolution estimates provide an accurate approach to determining long-term salinity loads as short-term events are accurately accounted for.
{"title":"Specific conductance and water type as a proxy model for salinity and total dissolved solids measurements in the Upper Colorado River Basin","authors":"R. Blaine McCleskey , Charles A. Cravotta III , Matthew P. Miller , Tanner W. Chapin , Fred Tillman , Gabrielle L. Keith","doi":"10.1016/j.apgeochem.2025.106358","DOIUrl":"10.1016/j.apgeochem.2025.106358","url":null,"abstract":"<div><div>Salinity levels in streams and tributaries of the Colorado River Basin have been a major concern for the United States and Mexico for over 50 years as the water is used by millions of people for domestic and industrial purposes. Recently, the United States Geological Survey expanded stream monitoring networks including the number of sites where continuous (15-min) specific conductance is measured in the Colorado River Headwaters and Gunnison River Basin located east of the Colorado-Utah state line (hereafter, UCOL). The purpose of this study is to apply a proxy method to determine salinity and total dissolved solids concentrations from specific conductance and major-ion water type that is applicable to monitoring sites in the UCOL. Within the UCOL, carbonate rich waters originate from high-elevation mountain regions in the eastern UCOL, calcium sulfate rich waters are mainly found in the western half of the UCOL including the Gunnison River Basin, and waters of variable composition are found along the lower reaches of the Colorado River and Eagle River. It was found that the chemistry of sites with variable composition changes seasonally and is impacted by both geogenic and anthropogenic processes, potentially including seasonal application of deicing road salt. The specific conductance – water type proxy can be used to reliably (±10 %) predict salinity and total dissolved solids at 66 monitoring sites in the UCOL. The method is rapid, can generate high-resolution measurements, is cost-effective, and greatly expands the utility of specific conductance measurements. Furthermore, the high-resolution estimates provide an accurate approach to determining long-term salinity loads as short-term events are accurately accounted for.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"184 ","pages":"Article 106358"},"PeriodicalIF":3.1,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643649","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}
Pub Date : 2025-03-13DOI: 10.1016/j.apgeochem.2025.106357
Kelin Zhang , Danqing Liu , Jinhao Yu , Changzhong Xu , Yilian Li
Amorphous iron sulfides (FeSx), which are more powerful than crystalline FeSx in reduction, are commonly found on the surfaces of many sulfidated nanoscale zero-valent iron (nZVI). However, due to the interference of nZVI, the reduction performance of FeSx is still unknown. In this paper, we synthesized efficient amorphous iron polysulfide (AIPS) with FeSO4 and CaSx and checked its reduction ability using Cr(VI) as a model contaminant, and found that the reactivity and amorphous structure of AIPS were significantly affected by the titration rate of CaSx during synthesis. The removal of Cr(VI) by AIPS synthesized at a titration time of 120 min was 81.9 mg/g, which was 10.6 times higher than that of AIPS synthesized within 6 min (7.7 mg/g). The improved AIPS can be applicable for Cr(VI) removal via simultaneous adsorption, reduction and precipitation at wide pH range and in the coexistence of ionic and natural organic matter (NOM). Using a reactive transport model, it can be found that FeS and FeS2 in AIPS contribute 85.01 % and 14.99 % to the Cr(VI) reduction, respectively. FeSx (x > 2), also as a reaction by-product of the Cr(VI) reduction by FeS and FeS2, hinders the reduction of Cr(VI).
{"title":"Investigation on the performance and mechanism of Cr(VI) immobilization with improved amorphous iron polysulfide: Batch experiments and numerical simulation","authors":"Kelin Zhang , Danqing Liu , Jinhao Yu , Changzhong Xu , Yilian Li","doi":"10.1016/j.apgeochem.2025.106357","DOIUrl":"10.1016/j.apgeochem.2025.106357","url":null,"abstract":"<div><div>Amorphous iron sulfides (FeS<sub>x</sub>), which are more powerful than crystalline FeS<sub>x</sub> in reduction, are commonly found on the surfaces of many sulfidated nanoscale zero-valent iron (nZVI). However, due to the interference of nZVI, the reduction performance of FeS<sub>x</sub> is still unknown. In this paper, we synthesized efficient amorphous iron polysulfide (AIPS) with FeSO<sub>4</sub> and CaS<sub>x</sub> and checked its reduction ability using Cr(VI) as a model contaminant, and found that the reactivity and amorphous structure of AIPS were significantly affected by the titration rate of CaS<sub>x</sub> during synthesis. The removal of Cr(VI) by AIPS synthesized at a titration time of 120 min was 81.9 mg/g, which was 10.6 times higher than that of AIPS synthesized within 6 min (7.7 mg/g). The improved AIPS can be applicable for Cr(VI) removal via simultaneous adsorption, reduction and precipitation at wide pH range and in the coexistence of ionic and natural organic matter (NOM). Using a reactive transport model, it can be found that FeS and FeS<sub>2</sub> in AIPS contribute 85.01 % and 14.99 % to the Cr(VI) reduction, respectively. FeS<sub>x</sub> (x > 2), also as a reaction by-product of the Cr(VI) reduction by FeS and FeS<sub>2</sub>, hinders the reduction of Cr(VI).</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"184 ","pages":"Article 106357"},"PeriodicalIF":3.1,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643650","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}
Pub Date : 2025-03-11DOI: 10.1016/j.apgeochem.2025.106356
Bo Zhang , Haoran Wu , Yang Liu , Peihua Li , Zhihong Zheng
Water quality degradation due to seawater intrusion is a globally significant environmental and geological issue. Cut-off walls, besides mitigating seawater intrusion, can alter groundwater flow direction and rate. Re-analysis recharge sources in coastal aquifers with cut-off walls is crucial for hydrogeological research and water resource management. Our study focused on the Lower Dagu River, where cut-off walls were installed. We employed the M3-MIX method to analyze groundwater recharge sources. The qualitative assessment revealed a substantial reduction in regional hydraulic connections across the cut-off walls, although weak seasonal connections persist due to groundwater level fluctuations and wall heights. Using M3-MIX, we identified four recharge sources in the south area—three salt groundwater sources and one saline surface water source—with mixing ratios of 1.4 %, 44.3 %, 41.8 %, and 12.5 %, respectively. In the north area, three recharge sources were identified—a river water sample, a saline surface water sample, and a groundwater sample—with mixing ratios of 14.9 %, 26.8 %, and 58.3 %, respectively. Our findings underscore the impact of cut-off walls on recharge sources and highlight the importance of re-analysis these sources for effective exploitation and protection of coastal aquifer water resources.
{"title":"Groundwater recharge sources analysis of coastal aquifer under the impact of cut-off walls: A case study of the Dagu River","authors":"Bo Zhang , Haoran Wu , Yang Liu , Peihua Li , Zhihong Zheng","doi":"10.1016/j.apgeochem.2025.106356","DOIUrl":"10.1016/j.apgeochem.2025.106356","url":null,"abstract":"<div><div>Water quality degradation due to seawater intrusion is a globally significant environmental and geological issue. Cut-off walls, besides mitigating seawater intrusion, can alter groundwater flow direction and rate. Re-analysis recharge sources in coastal aquifers with cut-off walls is crucial for hydrogeological research and water resource management. Our study focused on the Lower Dagu River, where cut-off walls were installed. We employed the M3-MIX method to analyze groundwater recharge sources. The qualitative assessment revealed a substantial reduction in regional hydraulic connections across the cut-off walls, although weak seasonal connections persist due to groundwater level fluctuations and wall heights. Using M3-MIX, we identified four recharge sources in the south area—three salt groundwater sources and one saline surface water source—with mixing ratios of 1.4 %, 44.3 %, 41.8 %, and 12.5 %, respectively. In the north area, three recharge sources were identified—a river water sample, a saline surface water sample, and a groundwater sample—with mixing ratios of 14.9 %, 26.8 %, and 58.3 %, respectively. Our findings underscore the impact of cut-off walls on recharge sources and highlight the importance of re-analysis these sources for effective exploitation and protection of coastal aquifer water resources.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"183 ","pages":"Article 106356"},"PeriodicalIF":3.1,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610388","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}
Pub Date : 2025-03-10DOI: 10.1016/j.apgeochem.2025.106354
Yan Zhang , Yi Liu
Iron separation from different solid phases is essential for evaluating the environmental function of iron in sediments. Oxalate is a commonly used extractant that effectively extract iron(hydro)oxides in sediments by complexation. However, when using spectrophotometry method, excess oxalate will interfere the complexation of iron with 1,10-phenanthroline leading to the failure of iron measurement. In this study, we discovered an effective method for spectrophotometric analysis of iron samples with oxalate by adjusting the pH to 7–9, which changes the structure of the Fe-oxalate complexes and ensured the complexation of iron with 1,10-phenanthroline. Further exploration indicates that photolysis and heating also decompose Fe-oxalate complexes, but the performance is not as good as pH adjustment. The standard solution exhibits a strong linear relationship between absorbance (Abs) and concentration (Con): Abs = 0.1934 × Con + 0.1360, with a R2 of 0.9997, accuracy of 97.1 %, and relative standard deviation of 1.4 %, which demonstrate the reliability of this method. Overall, the pretreatment is simple, and the influence of the organic solvent (oxalate) is diminished after pH adjustment. This method is expected to contribute to community by providing a new reliable, effective, less pre-treatment, economical, and sensitive testing approach and hopefully assist in the investigation on environmental function of iron minerals.
{"title":"A new 1,10-phenanthroline method for oxalate-extractable iron measurement","authors":"Yan Zhang , Yi Liu","doi":"10.1016/j.apgeochem.2025.106354","DOIUrl":"10.1016/j.apgeochem.2025.106354","url":null,"abstract":"<div><div>Iron separation from different solid phases is essential for evaluating the environmental function of iron in sediments. Oxalate is a commonly used extractant that effectively extract iron(hydro)oxides in sediments by complexation. However, when using spectrophotometry method, excess oxalate will interfere the complexation of iron with 1,10-phenanthroline leading to the failure of iron measurement. In this study, we discovered an effective method for spectrophotometric analysis of iron samples with oxalate by adjusting the pH to 7–9, which changes the structure of the Fe-oxalate complexes and ensured the complexation of iron with 1,10-phenanthroline. Further exploration indicates that photolysis and heating also decompose Fe-oxalate complexes, but the performance is not as good as pH adjustment. The standard solution exhibits a strong linear relationship between absorbance (<em>Abs</em>) and concentration (<em>Con</em>): <em>Abs</em> = 0.1934 × <em>Con</em> + 0.1360, with a R<sup>2</sup> of 0.9997, accuracy of 97.1 %, and relative standard deviation of 1.4 %, which demonstrate the reliability of this method. Overall, the pretreatment is simple, and the influence of the organic solvent (oxalate) is diminished after pH adjustment. This method is expected to contribute to community by providing a new reliable, effective, less pre-treatment, economical, and sensitive testing approach and hopefully assist in the investigation on environmental function of iron minerals.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"183 ","pages":"Article 106354"},"PeriodicalIF":3.1,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628110","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}
Pub Date : 2025-03-08DOI: 10.1016/j.apgeochem.2025.106332
Felix Berg, Christopher Sirleaf, Janik Lohmann, Markus Breckheimer, Tobias Reich
The capability of the combined approach of time-of-flight secondary ion mass spectrometry (TOF-SIMS) and resonant laser secondary neutral mass spectrometry (rL-SNMS) for the analysis of diffusion samples of in Opalinus Clay (OPA) under aerobic conditions was investigated at the micrometer scale. The speciation of Pu in the diffusion reservoir with OPA pore water (pH 7.6) was determined as using capillary electrophoresis coupled to inductively coupled plasma mass spectrometry (CE-ICP-MS). Using modern 3D printing techniques, a simple and easily scalable experimental setup was developed and adapted to the requirements of TOF-SIMS and rL-SNMS. Together, these techniques allowed for the observation of the pristine diffusion profile of Pu while retaining information about the heterogeneous clay rock. For the experiment with 35 days of in-diffusion, the modeling of an averaged diffusion profile of approximately 300 µm length resulted in = 3.2(4) × 10-15 m2 s-1. TOF-SIMS and rL-SNMS mappings showed heterogeneous distributions of Pu inside the clay rock and correlations with the matrix elements Fe and Ca, pointing to pyrite and a cementing calcite phase as reactive mineral phases.
{"title":"Investigation of plutonium diffusion profiles in Opalinus Clay rock via TOF-SIMS and rL-SNMS","authors":"Felix Berg, Christopher Sirleaf, Janik Lohmann, Markus Breckheimer, Tobias Reich","doi":"10.1016/j.apgeochem.2025.106332","DOIUrl":"10.1016/j.apgeochem.2025.106332","url":null,"abstract":"<div><div>The capability of the combined approach of time-of-flight secondary ion mass spectrometry (TOF-SIMS) and resonant laser secondary neutral mass spectrometry (rL-SNMS) for the analysis of diffusion samples of <figure><img></figure> in Opalinus Clay (OPA) under aerobic conditions was investigated at the micrometer scale. The speciation of Pu in the diffusion reservoir with OPA pore water (pH 7.6) was determined as <span><math><msubsup><mrow><mtext>PuO</mtext></mrow><mrow><mtext>2</mtext></mrow><mrow><mtext>+</mtext></mrow></msubsup></math></span> using capillary electrophoresis coupled to inductively coupled plasma mass spectrometry (CE-ICP-MS). Using modern 3D printing techniques, a simple and easily scalable experimental setup was developed and adapted to the requirements of TOF-SIMS and rL-SNMS. Together, these techniques allowed for the observation of the pristine diffusion profile of Pu while retaining information about the heterogeneous clay rock. For the experiment with 35 days of in-diffusion, the modeling of an averaged diffusion profile of approximately 300<!--> <!-->µm length resulted in <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>a</mi></mrow></msub></math></span> = 3.2(4) × 10<sup>-15</sup> <!-->m<sup>2</sup> <!-->s<sup>-1</sup>. TOF-SIMS and rL-SNMS mappings showed heterogeneous distributions of Pu inside the clay rock and correlations with the matrix elements Fe and Ca, pointing to pyrite and a cementing calcite phase as reactive mineral phases.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"183 ","pages":"Article 106332"},"PeriodicalIF":3.1,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610285","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}
Pub Date : 2025-03-07DOI: 10.1016/j.apgeochem.2025.106337
Shawan Dogramaci , Ilka Wallis , Peter Cook , Allan Kneeshaw
The semi-arid Hamersly Basin in Australia is the hub for extensive mining, which requires the relocation of a significant volume of groundwater for dry mining operations. Understanding water balance components is crucial for managing and conserving water resources. This study adopts a joint approach using isotopic and hydrochemical techniques to identify and quantify water sources and recharge dynamics to explain the integral functioning of a typical floodplain aquifer.
The observed chloride and stable isotopes suggest a mixing of recharge from high-rainfall cyclonic events and highly evaporated low-rainfall events at a ratio of 60:1. The highly evaporated water from light rainfall events would remain in the soil profile until mixed with precipitation from high-rainfall events recharge the underlying aquifers. The recharge rates by multiple methods range from 0.3 mm/y to 14.4 mm/y. Groundwaters have a unique hydrochemical signature and are characterised by high alkalinity and dissolved oxygen. The total dissolved solutes (TDS) range from fresh to brackish, however, most of the groundwater tends to have a TDS <1000 mg/L. The δ2H and δ18O concentrations of water samples vary over a narrow range despite a wide range of Cl concentrations. The data are consistent with salt concentration by evapotranspiration within the unsaturated zone, which becomes mixed with infiltration of rainfall from large cyclonic events. The hydrochemical pathway modelling for the major ion distribution shows that groundwater has evolved by evapo-concentration of rainfall prior to recharge in the unsaturated zone. This is followed by an increase in dissolved CO2 and the precipitation of carbonate minerals. Although the initial dissolved CO2 is acquired due to the decomposition of organic matter during passage through the unsaturated zone, the 10-fold higher CO2 (pCO2∼ −2.5) compared to atmospheric levels in the aquifer suggests the addition of further alkalinity due to aluminosilicate weathering. The negative correlation between δ34SSO4 and the SO4/Cl ratio suggests the addition of sulphate to groundwater with relatively depleted δ34SSO4 values. The source of sulphate is likely to be the oxidation of pyrite from the bedrock, which is characterised by high arsenopyrite concentration. The results suggest that climatic conditions impart a unique signature on the groundwater quality. The method can be utilised to constrain water balance components such as recharge for floodplain aquifers globally.
{"title":"Hydrochemical evolution of groundwater in a semi-arid environment verified through natural tracer and geochemical modelling, northwest Australia","authors":"Shawan Dogramaci , Ilka Wallis , Peter Cook , Allan Kneeshaw","doi":"10.1016/j.apgeochem.2025.106337","DOIUrl":"10.1016/j.apgeochem.2025.106337","url":null,"abstract":"<div><div>The semi-arid Hamersly Basin in Australia is the hub for extensive mining, which requires the relocation of a significant volume of groundwater for dry mining operations. Understanding water balance components is crucial for managing and conserving water resources. This study adopts a joint approach using isotopic and hydrochemical techniques to identify and quantify water sources and recharge dynamics to explain the integral functioning of a typical floodplain aquifer.</div><div>The observed chloride and stable isotopes suggest a mixing of recharge from high-rainfall cyclonic events and highly evaporated low-rainfall events at a ratio of 60:1. The highly evaporated water from light rainfall events would remain in the soil profile until mixed with precipitation from high-rainfall events recharge the underlying aquifers. The recharge rates by multiple methods range from 0.3 mm/y to 14.4 mm/y. Groundwaters have a unique hydrochemical signature and are characterised by high alkalinity and dissolved oxygen. The total dissolved solutes (TDS) range from fresh to brackish, however, most of the groundwater tends to have a TDS <1000 mg/L. The δ<sup>2</sup>H and δ<sup>18</sup>O concentrations of water samples vary over a narrow range despite a wide range of Cl concentrations. The data are consistent with salt concentration by evapotranspiration within the unsaturated zone, which becomes mixed with infiltration of rainfall from large cyclonic events. The hydrochemical pathway modelling for the major ion distribution shows that groundwater has evolved by evapo-concentration of rainfall prior to recharge in the unsaturated zone. This is followed by an increase in dissolved CO<sub>2</sub> and the precipitation of carbonate minerals. Although the initial dissolved CO<sub>2</sub> is acquired due to the decomposition of organic matter during passage through the unsaturated zone, the 10-fold higher CO<sub>2</sub> (pCO<sub>2</sub>∼ −2.5) compared to atmospheric levels in the aquifer suggests the addition of further alkalinity due to aluminosilicate weathering. The negative correlation between δ<sup>34</sup>S<sub>SO4</sub> and the SO<sub>4</sub>/Cl ratio suggests the addition of sulphate to groundwater with relatively depleted δ<sup>34</sup>S<sub>SO4</sub> values. The source of sulphate is likely to be the oxidation of pyrite from the bedrock, which is characterised by high arsenopyrite concentration. The results suggest that climatic conditions impart a unique signature on the groundwater quality. The method can be utilised to constrain water balance components such as recharge for floodplain aquifers globally.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"183 ","pages":"Article 106337"},"PeriodicalIF":3.1,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580468","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}
Pub Date : 2025-03-06DOI: 10.1016/j.apgeochem.2025.106344
Sarah Sarah , Waseem Shah , Farooq A. Dar , Shakil Ahmad Romshoo , Tanvi Arora
This study investigates the complex relationship between high-altitude stream hydrochemistry and geochemical processes in the Liddar catchment, a representative high-altitude watershed in the Western Himalayas. High-altitude catchments, like the Liddar, are critical as they are major freshwater sources, heavily influenced by snow and glacier melt contributions, making them particularly sensitive to climate change. The high-altitude location intensifies the seasonal contrast in hydrochemical signatures, driven by glacier and snowmelt inputs, which are distinct from low-altitude catchments that rely more on rainfall. We applied geochemical and bayesian stable water isotope modeling to distinguish the hydrochemical signatures during baseflow and intense melting periods. Across the seasons, stable isotope water analyses outline the diverse contributions of snowmelt, precipitation, and groundwater to streamflow. A large portion of streamflow is sourced from meltwater (62.05 ± 6.24%) in summer that reduces in spring by (51.34 ± 7.43%). In Autumn, meltwater contribution drops to 28.30 ± 7.24% and this contribution further drops significantly to 18.87 ± 3.68% during winter. Conversely, during winter and autumn a larger portion of the stream water is sourced from groundwater (60.45 ± 8.54% and 55.78 ± 7.37%) respectively. Groundwater contribution to baseflow decreases from 37.61 ± 5.58% to 28.91 ± 8.51% in spring and summer respectively. Mean residence time (MRT) of stream water, extending to 13 weeks during baseflow and shortening to 7 weeks during melting conditions, points to dynamic storage and flow path characteristics of the catchment. Geochemical modeling highlights the dissolution of minerals such as calcite, dolomite, and gypsum as key drivers of stream water chemistry. Baseflow period shows enrichment of major ions like calcium, magnesium, bicarbonate and trace elements like Ni and Cr exhibiting geochemical signatures suggestive of deeper flow paths and mineral dissolution from host rock formations. However, the intense melting periods demonstrate significant increase in trace elements like, Al, indicative of shallower sources suggesting interactions between melting snowpacks and regolith. Our study demonstrates that in undisturbed high-altitude watersheds the stream, groundwater, and soil chemistry effectively reflect the flow path dynamics. This research offers critical insights for adaptive water resource management strategies in high-altitude regions, which face unique challenges under changing climatic conditions, such as the mobilization of heavy metals and freshwater toxicity.
{"title":"Hydrochemical composition and hydrodynamics as proxies to identify the stream water sources and pathways in high-altitude catchments","authors":"Sarah Sarah , Waseem Shah , Farooq A. Dar , Shakil Ahmad Romshoo , Tanvi Arora","doi":"10.1016/j.apgeochem.2025.106344","DOIUrl":"10.1016/j.apgeochem.2025.106344","url":null,"abstract":"<div><div>This study investigates the complex relationship between high-altitude stream hydrochemistry and geochemical processes in the Liddar catchment, a representative high-altitude watershed in the Western Himalayas. High-altitude catchments, like the Liddar, are critical as they are major freshwater sources, heavily influenced by snow and glacier melt contributions, making them particularly sensitive to climate change. The high-altitude location intensifies the seasonal contrast in hydrochemical signatures, driven by glacier and snowmelt inputs, which are distinct from low-altitude catchments that rely more on rainfall. We applied geochemical and bayesian stable water isotope modeling to distinguish the hydrochemical signatures during baseflow and intense melting periods. Across the seasons, stable isotope water analyses outline the diverse contributions of snowmelt, precipitation, and groundwater to streamflow. A large portion of streamflow is sourced from meltwater (62.05 ± 6.24%) in summer that reduces in spring by (51.34 ± 7.43%). In Autumn, meltwater contribution drops to 28.30 ± 7.24% and this contribution further drops significantly to 18.87 ± 3.68% during winter. Conversely, during winter and autumn a larger portion of the stream water is sourced from groundwater (60.45 ± 8.54% and 55.78 ± 7.37%) respectively. Groundwater contribution to baseflow decreases from 37.61 ± 5.58% to 28.91 ± 8.51% in spring and summer respectively. Mean residence time (MRT) of stream water, extending to 13 weeks during baseflow and shortening to 7 weeks during melting conditions, points to dynamic storage and flow path characteristics of the catchment. Geochemical modeling highlights the dissolution of minerals such as calcite, dolomite, and gypsum as key drivers of stream water chemistry. Baseflow period shows enrichment of major ions like calcium, magnesium, bicarbonate and trace elements like Ni and Cr exhibiting geochemical signatures suggestive of deeper flow paths and mineral dissolution from host rock formations. However, the intense melting periods demonstrate significant increase in trace elements like, Al, indicative of shallower sources suggesting interactions between melting snowpacks and regolith. Our study demonstrates that in undisturbed high-altitude watersheds the stream, groundwater, and soil chemistry effectively reflect the flow path dynamics. This research offers critical insights for adaptive water resource management strategies in high-altitude regions, which face unique challenges under changing climatic conditions, such as the mobilization of heavy metals and freshwater toxicity.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"183 ","pages":"Article 106344"},"PeriodicalIF":3.1,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610284","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}
Pub Date : 2025-03-05DOI: 10.1016/j.apgeochem.2025.106343
Shanke Liu , Benxun Su , Wenjun Li , Jianming Liu
Potassium (K) isotopes are increasingly recognized as promising tracers for evaluating the impact of anthropogenic activities on the biogeochemical K cycle, particularly given the widespread use of K fertilizers in agriculture to mitigate soil K depletion. Understanding K isotope behavior in soil is essential because soil acts both as a carrier of fertilizers and as a source of K from weathered rocks. In this study, we determined the K isotopic compositions of K-bearing mineral fertilizers (KMFs), which were produced from K-feldspar through artificial hydrothermal alteration, exhibiting physicochemical properties similar to those of soil. The δ41K values of bulk K in KMFs range from −0.755 ± 0.023 ‰ to −0.095 ± 0.020 ‰. The K isotopic compositions of 0.5 mol/L acid-soluble K are close to those of bulk K in KMFs, in the range of −0.751 ± 0.043 ‰ to −0.103 ± 0.035 ‰. The observation of isotopically heavier water-soluble K compared to bulk sample K confirms the preferential enrichment of heavy K isotopes in aqueous solutions, consistent with observations in weathered rocks. A combined mechanism involving K–O bond-driven and diffusion-mediated K isotope fractionation offers a plausible explanation for the discrepancy between theoretical models and experimental observations. The application of K-bearing fertilizers has the potential to impact δ41K values in rivers and seas due to interactions among soil, plants, and water. Our findings contribute to a more comprehensive understanding of K cycling in ecosystems.
{"title":"Potassium isotope fractionation of potassium-bearing mineral fertilizers and its implications for global potassium cycle","authors":"Shanke Liu , Benxun Su , Wenjun Li , Jianming Liu","doi":"10.1016/j.apgeochem.2025.106343","DOIUrl":"10.1016/j.apgeochem.2025.106343","url":null,"abstract":"<div><div>Potassium (K) isotopes are increasingly recognized as promising tracers for evaluating the impact of anthropogenic activities on the biogeochemical K cycle, particularly given the widespread use of K fertilizers in agriculture to mitigate soil K depletion. Understanding K isotope behavior in soil is essential because soil acts both as a carrier of fertilizers and as a source of K from weathered rocks. In this study, we determined the K isotopic compositions of K-bearing mineral fertilizers (KMFs), which were produced from K-feldspar through artificial hydrothermal alteration, exhibiting physicochemical properties similar to those of soil. The δ<sup>41</sup>K values of bulk K in KMFs range from −0.755 ± 0.023 ‰ to −0.095 ± 0.020 ‰. The K isotopic compositions of 0.5 mol/L acid-soluble K are close to those of bulk K in KMFs, in the range of −0.751 ± 0.043 ‰ to −0.103 ± 0.035 ‰. The observation of isotopically heavier water-soluble K compared to bulk sample K confirms the preferential enrichment of heavy K isotopes in aqueous solutions, consistent with observations in weathered rocks. A combined mechanism involving K–O bond-driven and diffusion-mediated K isotope fractionation offers a plausible explanation for the discrepancy between theoretical models and experimental observations. The application of K-bearing fertilizers has the potential to impact δ<sup>41</sup>K values in rivers and seas due to interactions among soil, plants, and water. Our findings contribute to a more comprehensive understanding of K cycling in ecosystems.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"183 ","pages":"Article 106343"},"PeriodicalIF":3.1,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143621030","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}
Pub Date : 2025-03-04DOI: 10.1016/j.apgeochem.2025.106341
Lei Zhang , Lishuang Guo , Deyang Shi , Chuang Bao
Mercury isotopic fractionations in soils have been widely studied, but the mercury isotopic compositions in soils in earthquake fault zones are poorly understood. Here we investigated the fractionation characteristics of mercury isotopes in soils along the Anninghe-Zemuhe fault zone on the eastern margin of the Tibetan Plateau, Southwest China. The results showed that the δ202Hg values of soils ranged from −1.23‰ to 0.39‰ with an average of −0.86‰ ± 0.38‰, and the Δ199Hg values ranged from −0.46‰ to −0.02‰ with an average of −0.27‰ ± 0.12‰ (1SD, n = 22). The Δ199Hg values in deep soils were more negative than those in surface soils. The fault gouge had a more negative Δ199Hg value and was different from the geological source with near-zero Δ199Hg value. The characteristics of mercury isotope variations reveal that mercury-containing gas degasses from terrestrial and geological reservoirs in the Anninghe-Zemuhe fault zone. We demonstrate that mercury isotopes can reveal mercury sources from degassing in soils in active fault zones.
{"title":"Mercury isotope signatures in soils reveal degassing from fault zones on the eastern margin of the Tibetan Plateau","authors":"Lei Zhang , Lishuang Guo , Deyang Shi , Chuang Bao","doi":"10.1016/j.apgeochem.2025.106341","DOIUrl":"10.1016/j.apgeochem.2025.106341","url":null,"abstract":"<div><div>Mercury isotopic fractionations in soils have been widely studied, but the mercury isotopic compositions in soils in earthquake fault zones are poorly understood. Here we investigated the fractionation characteristics of mercury isotopes in soils along the Anninghe-Zemuhe fault zone on the eastern margin of the Tibetan Plateau, Southwest China. The results showed that the δ<sup>202</sup>Hg values of soils ranged from −1.23‰ to 0.39‰ with an average of −0.86‰ ± 0.38‰, and the Δ<sup>199</sup>Hg values ranged from −0.46‰ to −0.02‰ with an average of −0.27‰ ± 0.12‰ (1SD, n = 22). The Δ<sup>199</sup>Hg values in deep soils were more negative than those in surface soils. The fault gouge had a more negative Δ<sup>199</sup>Hg value and was different from the geological source with near-zero Δ<sup>199</sup>Hg value. The characteristics of mercury isotope variations reveal that mercury-containing gas degasses from terrestrial and geological reservoirs in the Anninghe-Zemuhe fault zone. We demonstrate that mercury isotopes can reveal mercury sources from degassing in soils in active fault zones.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"183 ","pages":"Article 106341"},"PeriodicalIF":3.1,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580515","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}
Pub Date : 2025-03-03DOI: 10.1016/j.apgeochem.2025.106340
Wenbin Zhao , Zhengfu Guo , Wenjing Liu , Antonio Caracausi , Dario Buttitta , Yutao Sun , Jujing Li , Xiangang Xie , Chunqing Sun , Zhifang Xu
Degassing of carbon-rich fluids through hydrothermal activities in continental fault systems represents one of the dominant ways within global carbon cycle. Complex phase transitions and geochemical transformations occur during their ascent to the surface, leading to chemical and isotopic composition alterations of fluids. Here, we present a combined dataset of chemical and isotopic data of spring water and bubbling gas samples collected from strike-slip Karakoram fault (KKF) and northern Xaniza rift (NXR) region in southern Tibetan Plateau, aiming to provide comprehensive constrain on the provenance and inventory of carbon-rich fluids in hydrothermal systems. The carbon isotopic compositions of dissolved inorganic carbon (DIC) positively correlate with dissolved values of CO2, suggesting significant hydrothermal degassing in the system. The initial concentrations and carbon isotopic compositions of pre-degassing DIC, as well as the degrees of degassing, are determined based on the fractionation modeling between gaseous CO2 and residual DIC. In order to provide a quantitative constraint on the pristine DIC inventory in hydrothermal waters, we conducted an integrated modeling method involving calcite precipitation, hydrothermal degassing, and mixing between deep-sourced carbon and organic matter. The modeling suggests that hydrothermal fluids from the NXR region exhibit slightly higher proportions of endogenic carbon (91.0%–95.9%) but lower contribution of subsurface organic matter (1.5%–6.8%) compared to the KKF region (75.1%–88.1% and 4.6%–24.9%). Our study emphasizes the substantial role of extensional continental rifting in deep carbon degassing through hydrothermal activities within the India-Asia collision zones.
{"title":"Deep carbon degassing from strike-slip fault and rift system in India-Asia collision zone: Insights from fluid geochemistry in hydrothermal systems","authors":"Wenbin Zhao , Zhengfu Guo , Wenjing Liu , Antonio Caracausi , Dario Buttitta , Yutao Sun , Jujing Li , Xiangang Xie , Chunqing Sun , Zhifang Xu","doi":"10.1016/j.apgeochem.2025.106340","DOIUrl":"10.1016/j.apgeochem.2025.106340","url":null,"abstract":"<div><div>Degassing of carbon-rich fluids through hydrothermal activities in continental fault systems represents one of the dominant ways within global carbon cycle. Complex phase transitions and geochemical transformations occur during their ascent to the surface, leading to chemical and isotopic composition alterations of fluids. Here, we present a combined dataset of chemical and isotopic data of spring water and bubbling gas samples collected from strike-slip Karakoram fault (KKF) and northern Xaniza rift (NXR) region in southern Tibetan Plateau, aiming to provide comprehensive constrain on the provenance and inventory of carbon-rich fluids in hydrothermal systems. The carbon isotopic compositions of dissolved inorganic carbon (DIC) positively correlate with dissolved values of CO<sub>2</sub>, suggesting significant hydrothermal degassing in the system. The initial concentrations and carbon isotopic compositions of pre-degassing DIC, as well as the degrees of degassing, are determined based on the fractionation modeling between gaseous CO<sub>2</sub> and residual DIC. In order to provide a quantitative constraint on the pristine DIC inventory in hydrothermal waters, we conducted an integrated modeling method involving calcite precipitation, hydrothermal degassing, and mixing between deep-sourced carbon and organic matter. The modeling suggests that hydrothermal fluids from the NXR region exhibit slightly higher proportions of endogenic carbon (91.0%–95.9%) but lower contribution of subsurface organic matter (1.5%–6.8%) compared to the KKF region (75.1%–88.1% and 4.6%–24.9%). Our study emphasizes the substantial role of extensional continental rifting in deep carbon degassing through hydrothermal activities within the India-Asia collision zones.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"183 ","pages":"Article 106340"},"PeriodicalIF":3.1,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143593108","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}
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