Applied Geochemistry最新文献

{"title":"Exploring abiotic non-catalytic polyphenol-Maillard humification in light-limited environment","authors":"Afzaal Ashraf ,&nbsp;Wu Haoyu ,&nbsp;Zhang Baijia ,&nbsp;Chu Aodan ,&nbsp;Yang Yue ,&nbsp;Fanping Zhu ,&nbsp;Zhifeng Li ,&nbsp;Shengli Lian ,&nbsp;Zhen Hu ,&nbsp;Yang Zeng","doi":"10.1016/j.apgeochem.2025.106368","DOIUrl":"10.1016/j.apgeochem.2025.106368","url":null,"abstract":"<div><div>Abiotic humification involving polyphenol-maillard precursors leads to the formation of Humic-like substances (HLSs). Previous research has been conducted on catalytic or mineral-associated pathways, although the physicochemical role of noncatalytic abiotic pathway in light-limited environments remains unexplored. Current study investigates the noncatalytic polycondensation reaction between catechol (free polyphenol) and Maillard precursors (glucose &amp; glycine) to synthesize HLSs. In the presence of catechol, singlet oxygen (¹O₂) production solely derived the reaction at mild temperature and light-limited conditions, independent of photochemical or Fenton-type reactions. Spectroscopic analyses revealed a dominant presence of aliphatic moieties, consistent with ultra-high-resolution mass spectrometry (UHRMS) data. Polycondensation reaction released elevated CO₂ levels and decline in pH, indicating aromatic ring cleavage, carboxyl group formation and transformation of aromatics into aliphatic fragments. Additionally, Van Krevelen analysis showed increased O/C ratio in HLS. Notably, the key components included acidic and glucose oxidation products, along with some Maillard reaction intermediates (confirmed with Kendrick Mass analysis). This study provides a novel noncatalytic abiotic humification pathway, corroborating with environments where light-assisted and photochemical processes are minimal such as subsurface soils and underground water.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"184 ","pages":"Article 106368"},"PeriodicalIF":3.1,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725988","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":"Properties of solid bitumen formed during hydrous, anhydrous, and brine pyrolysis of oil shale: Implications for solid bitumen reflectance in source-rock reservoirs","authors":"Paul C. Hackley ,&nbsp;Justin E. Birdwell ,&nbsp;Ryan McAleer","doi":"10.1016/j.apgeochem.2025.106365","DOIUrl":"10.1016/j.apgeochem.2025.106365","url":null,"abstract":"<div><div>Solid bitumen reflectance (BR_o in %) is widely used as a thermal maturity proxy in source-rock reservoirs, yet solid bitumen texture and physical attributes may be affected by varying environmental constraints during its formation, e.g., water saturation, mineral catalysis, or salinity. Herein we investigated the development of solid bitumen properties during artificial maturation using three diverse (lacustrine to marine) oil shale samples containing abundant amorphous H-rich sedimentary organic matter (bituminite). The oil shales were treated via pyrolysis (320 °C, 72 h) using hydrous, anhydrous, and brine conditions, causing the development of a newly formed solid bitumen in the experiment residues from the thermal conversion of bituminite. The properties of the newly formed solid bitumen then were evaluated via geochemical screening tests, optical and electron microscopy, and infrared spectroscopy. Experimental residues also were treated via solvent extraction, allowing characterization of the effects of extraction on solid bitumen. Results showed that bituminite with higher resin and asphaltene components evolved to a solid bitumen with higher reflectance (as a percentage of the original value) when exposed to the same heat treatment, relative to bituminite with higher saturate and aromatic components. Aromatization of solid bitumen also was generally more pronounced in the presence of deionized water relative to anhydrous conditions, supporting prior observations. These results suggest the compositions of primary sedimentary organic matter, and the local concentration of water, affect the development of solid bitumen during thermal advance, potentially explaining the origin of multiple solid bitumen populations with varying reflectance in source-rock reservoir samples or in a single microscope field. Experiments using brine were inconclusive regarding enhanced/decreased aromatization, which could be attributed to the salinities of the brines used in the tests. Extraction of residues caused a consistent increase in BR_o values, suggesting that migrating or expelled oils could cause an increase in BR_o via natural solvation and absent an increase in temperature. This work provides insights into the development and evolution of BR_o in source-rock reservoirs as a function of the composition of the original bituminite and changing environmental conditions, with potentially broad application for petroleum prospecting and resource estimation.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"185 ","pages":"Article 106365"},"PeriodicalIF":3.1,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143826356","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":"Major and rare earth elements geochemistry of the Cretaceous ocean red beds: Implications for the terrestrial silicate weathering and marine sedimentary environment","authors":"Yuanchuan Li ,&nbsp;Wenjing Liu ,&nbsp;Xiangli Wang ,&nbsp;Jiangyi Zhang ,&nbsp;Xi Chen ,&nbsp;Hanwei Yao ,&nbsp;Zhifang Xu","doi":"10.1016/j.apgeochem.2025.106364","DOIUrl":"10.1016/j.apgeochem.2025.106364","url":null,"abstract":"<div><div>During the Cretaceous, global ocean redox state fluctuated dramatically, resulting in the deposition of black shales and Cretaceous Ocean Red Beds (CORB). Herein, the chemical weathering intensity indexes calculated by major elements and the geochemical behaviors of rare earth elements (REE) were investigated in the late CORBs and the underlying shales deposited in southern Tibet and the Northern Atlantic. The original deposition environment of CORBs from both sites showed intensified chemical weathering extent under relatively warm and humid conditions, despite an overall global cooling trend during the late Cretaceous. The large variations of Ce anomalies (0.65–1.46) and LREE/HREE ratios (0.60–0.94) normalized by Post-Archean Australian Shale (PAAS) in the shale layers were the results of Fe mineral transformation, and the generally positive PAAS-normalized Eu anomalies (0.93–1.50) were likely controlled by the material sources. The CORBs displayed higher contents of total REE and Fe₂O₃ than the underlying shales, and had a similar covariant relationship with the chemical weathering intensity. This study suggested that a large amount of terrigenous iron was transported into the oxic Cretaceous Ocean by continental weathering, and REE fractionations were potential indicators to reflect sedimentary location and relatively sedimentation rate of ocean red beds formation across the Ediacaran and Phanerozoic.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"184 ","pages":"Article 106364"},"PeriodicalIF":3.1,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716000","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 3D hydrogeochemistry and particle tracking in detecting groundwater flow patterns within an aapa mire–outwash plain system in a boreal environment at a mining development site","authors":"Åberg Annika Katarina ,&nbsp;Korkka-Niemi Kirsti ,&nbsp;Åberg Susanne Charlotta ,&nbsp;Rautio Anne","doi":"10.1016/j.apgeochem.2025.106360","DOIUrl":"10.1016/j.apgeochem.2025.106360","url":null,"abstract":"&lt;div&gt;&lt;div&gt;A combination of statistical hydrogeochemical methods, PCA, correlation calculations and SiroSOM clustering, as well as groundwater flow modelling with particle tracking, was applied in the 3D hydrogeochemical characterization of the Sakatti mining development site, located in an area of complex Quaternary sediments and weathered/fractured bedrock in northern Finland. This study enhanced the understanding of the groundwater flow paths through the subsurface–mire complex, recharge areas of the study site, and chemical signatures of different water types.&lt;/div&gt;&lt;div&gt;The flow paths of the site are variable and occur at three scales: large-scale (&gt;1000 m), medium-scale (1000–100 m) and small-scale flow (&lt;100 m). Large-scale flow paths start from mire islands, continuing through subpeat sediments and the weathered and fractured bedrock, ending in the River Kitinen. Medium-scale flow paths go from the outwash plain areas and adjacent finger-like mire areas via the subsurface to the river. Small-scale flow occurs in the banks of the River Kitinen and in the Viiankiaapa mire and is related to variation in the topography, as well as the string and flark pattern of the mire. The average backward (BW)-tracked residence time is ca. 150, 25, 6 years for the large, medium, and small-scale flow paths, respectively.&lt;/div&gt;&lt;div&gt;The &lt;em&gt;d&lt;/em&gt;-excess distribution displays areas with evaporated (&lt;5), meteoric (&gt;8), and mixed water signals. Particle tracking and &lt;em&gt;d&lt;/em&gt;-excess values indicate that groundwater recharges in outwash plain areas and in the Viiankiaapa mire area. The low &lt;em&gt;d&lt;/em&gt;-excess values in springs of the river bank and shallow bedrock wells indicate water flow from the Viiankiaapa mire.&lt;/div&gt;&lt;div&gt;The simulated BW tracking in outwash plain areas indicated average residences times corresponding to CFC-12 and &lt;sup&gt;3&lt;/sup&gt;H/&lt;sup&gt;3&lt;/sup&gt;He ages. Evaluation of the likely recharge area with BW tracking based on a &lt;em&gt;d&lt;/em&gt;-excess limit (&lt;5 for evaporated waters) showed the best correspondence in GW wells and mire porewaters and was related to flow paths longer than 20 m. Surface water samples and spring samples displayed intermediate or low correspondence.&lt;/div&gt;&lt;div&gt;Most of the waters represent Ca–HCO&lt;sub&gt;3&lt;/sub&gt; water types. SiroSOM analysis grouped the water samples into seven hydrogeochemical clusters including groundwaters with elevated concentrations to diluted surface waters. In general, the concentrations of elements were lowest in groundwater travelling through peat unit and highest in groundwater flowing in bedrock due to the longer residence time and flow path. The hydrogeochemical signal of anoxic, Fe- and Mn-rich mire (pore) waters is not evident in spring samples due to the oxidation of water in the springs and the precipitation of Fe and Mn.&lt;/div&gt;&lt;div&gt;Understanding of the groundwater flow patterns, as well as the recharge and discharge areas in a mining development site enables successful planning and positionin","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"186 ","pages":"Article 106360"},"PeriodicalIF":3.1,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143905866","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":"Comparison of naturally altered archaeological glasses from a marine environment with accelerated laboratory tests; implications for modelling long-term corrosion","authors":"Clare L. Thorpe ,&nbsp;Nick Aldred ,&nbsp;Stuart Creasey-Gray ,&nbsp;Martin C. Stennett ,&nbsp;Eperke A. Rencz ,&nbsp;Susan Nehzati ,&nbsp;Latham T. Haigh ,&nbsp;Garry Manifold ,&nbsp;Nishta Vallo ,&nbsp;Christoph Lenting ,&nbsp;Claire L. Corkhill ,&nbsp;Russell J. Hand","doi":"10.1016/j.apgeochem.2025.106363","DOIUrl":"10.1016/j.apgeochem.2025.106363","url":null,"abstract":"<div><div>Glass ingots of lead silicate composition from the shipwreck of the <em>Albion</em> were studied to ascertain the chemistry and mineralogy of alteration products after exposure to seawater for 220 years. Alteration observed on natural samples was compared to that of the same glasses exposed to short-term, high temperature, laboratory dissolution tests in synthetic seawater and significant differences were observed. Alteration layers on natural samples were more chemically complex having sequestered high concentrations of elements present only at trace quantities in seawater. Electron microprobe analysis and microfocus x-ray absorption spectroscopy shows that P, most likely released by biological activity in the vicinity of the wreck, accumulated in naturally altered samples to form Pb–Ca-phosphate phases whilst Pb-sulphate phases formed in laboratory tests. Meanwhile Fe, present at &lt; 0.3 wt % in the glass and ppb concentrations in seawater, accumulated to form Fe-silicates whilst Mg-silicates predominated in laboratory tests. Biologically induced corrosion of naturally altered samples was also considered. Experiments conducted to test barnacle settlement rates suggest that biotoxic elements within the glass, primarily Pb but potentially also Cu, Co and Ni deterred barnacle settlement. Despite this toxicity, some colonisation of the glass surface by both barnacles and bryozoan did occur and, whilst barnacles appeared to protect against chemical attack, bryozoan colonies caused increased cracking, possibly due stress created at the glass surface. Results highlight the challenges in recreating open, natural systems in laboratory settings and demonstrate that elements present at low concentrations can have a significant impact over long timescales.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"184 ","pages":"Article 106363"},"PeriodicalIF":3.1,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684158","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":"Paleoenvironmental assessment of a lower Jurassic succession in the NW-German Basin employing DRIFTS","authors":"Tim Marten ,&nbsp;Yves Alain Brügger ,&nbsp;Guido Lars Bruno Wiesenberg ,&nbsp;Lorenz Schwark","doi":"10.1016/j.apgeochem.2025.106362","DOIUrl":"10.1016/j.apgeochem.2025.106362","url":null,"abstract":"<div><div>High-resolution reconstruction of paleoenvironmental conditions of sedimentation requires the qualitative and quantitative assessment of the major sediment-forming fractions, i.e., carbonate, clay, quartz and organic matter. Simultaneous determination of these sediment-forming fractions by cost-effective and rapid methodologies is difficult to achieve. Previously, either XRF-, XRD-, and microscopy-based methods, or combinations thereof have been employed, complemented by organic carbon analysis. We here present a simultaneous approximation of the most relevant sediment-forming constituents, carbonate, clay, and organic matter, as well as quartz and feldspar, if present in sufficient quantity, by Diffusive Infra-Red Fourier Transformation Spectroscopy (DRIFTS). The technique does not require elaborated sample preparation or large sample amounts and is conducted without analytical reagents, solvents or carrier gases, thereby allowing high sample through-put. As such, DRIFTS investigation is ideal for stratigraphically highly-resolved studies. We applied DRIFTS to a sediment succession of Pliensbachian/Toarcian age and differentiated six sedimentary facies intervals that previously had been established based on application of more sophisticated but also more cost- and time-affording methodologies like XRF, XRD and programmed pyrolysis. While having been applied previously to characterization of soils and kerogen concentrates, we here demonstrate applicability of the DRIFTS technique to analysis of pre-Quaternary and consolidated sedimentary sequences.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"184 ","pages":"Article 106362"},"PeriodicalIF":3.1,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684156","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":"Hydrochemistry and stable isotopes of the Ili River: Deciphering spatiotemporal moisture sources and climatic drivers in Central Asia's wet island","authors":"Haizhao Jing ,&nbsp;Hongbiao Gu ,&nbsp;Shuangshuang Lan ,&nbsp;Haibin Wei ,&nbsp;Jiyi Jiang ,&nbsp;He Wang ,&nbsp;Mingqian Li ,&nbsp;Baoming Chi","doi":"10.1016/j.apgeochem.2025.106345","DOIUrl":"10.1016/j.apgeochem.2025.106345","url":null,"abstract":"<div><div>The Ili Valley in northwestern China plays a vital role as a green oasis in the large-scale moisture cycle and water utilization in Central Asia's core. To clarify the distinctive hydrochemical characteristics and genesis that differentiate it from the neighboring arid areas, the first large-scale sampling of river water covering the entire Ili Valley was conducted. The results show that the hydrochemical and stable isotopic characteristics vary spatially and seasonally among the tributaries. Rock weathering mainly controls the major ion composition in river water, which gradually varies along the river due to evaporation and snowmelt. The δ²H and δ¹⁸O values range from −103.00‰ to −72.00‰ and −15.00‰ to −9.60‰, respectively. Contrary to what is expected, the δ²H &amp; δ¹⁸O in the Tekes &amp; Ili Rivers are enriched with altitude, showing an “inverse altitude effect\" influenced by topography and moisture sources; the Karsh River has lower δ¹⁸O values due to snowmelt; the Kunes River has a U-shaped trend of isotopic concentrations and high <em>d</em>-excess values by precipitation. Both the seasonal deviations in river waterlines (RWL¹ vs RWL²) and the backward trajectory by HYSPLIT 4.0 showed that the origin of spring moisture at low troposphere in the Ili Valley could be traced to the surrounding regions, the summer moisture mixed with frigid air from the Arctic Ocean, while sub-cloud evaporation and surface-groundwater interaction are also the factor internally within the basin. The findings complement the basin-scale hydrochemical monitoring data and help investigate the large-scale hydrological cycle.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"184 ","pages":"Article 106345"},"PeriodicalIF":3.1,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785976","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":"Groundwater arsenic and the role of secondary Fe/Mn hydroxides in a volcaniclastic aquifer, Guanacaste, Costa Rica","authors":"Henry Ericson ,&nbsp;Molly Klingner ,&nbsp;Julianna Martinez ,&nbsp;Ian Nolon ,&nbsp;Lila Olson ,&nbsp;Robin Potter ,&nbsp;Peter Ryan ,&nbsp;Kira Zalis Waldman ,&nbsp;Guillermo E. Alvarado","doi":"10.1016/j.apgeochem.2025.106359","DOIUrl":"10.1016/j.apgeochem.2025.106359","url":null,"abstract":"<div><div>Elevated arsenic (As) in the regional water supply from a volcaniclastic aquifer in Costa Rica is an example of the increasing problem of As-contaminated waters in aquifers throughout Latin America. In this study, potential sources of As were assessed by (1) measuring the solid-phase chemical composition of volcaniclastic aquifer sediments and intercalated paleosols, (2) analyzing As speciation and availability by sub-millimeter scale elemental mapping and targeted chemical extractions, and (3) mapping spatial trends of As in shallow drinking water wells, surficial hot springs, and deep wells producing geothermal waters. Iron-manganese hydroxides (Fe/Mn hydroxides) in this aquifer system contain 210–530 ppm As that sorbs to this solid phase when released by chemical weathering of As-bearing volcanic glass. Arsenic is primarily transferred from solid to aqueous state when groundwater conditions shift from oxidizing to reducing, likely driven by presence of organic matter or periods of water logging (e.g. rainy season or irrigation). The occurrence of isolated hot springs raises the possibility that arsenic in groundwater may result from mixing of low-As meteoric waters with localized high-As thermal waters (hot springs). However, experimental evidence for release of As upon reductive dissolution of Fe/Mn hydroxides in solid-phase aquifer sediments plus the homogeneous and widespread 10–60 ppb As content in drinking water wells indicate that Fe/Mn hydroxide breakdown is the primary cause of the widespread As contamination in the regional aquifer. Locally, natural upwelling of thermal waters may affect wells in close proximity to surficial hot springs, but minimal evidence of this was observed in this study. Given the high incidence of elevated As in groundwater in volcaniclastic aquifers in Latin America and similar environments globally, these results are applicable to understanding As speciation and source, in particular drawing attention to the significance of secondary Fe/Mn hydroxides in arsenic cycling in volcaniclastic aquifers.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"184 ","pages":"Article 106359"},"PeriodicalIF":3.1,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684157","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":"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 ,&nbsp;Charles A. Cravotta III ,&nbsp;Matthew P. Miller ,&nbsp;Tanner W. Chapin ,&nbsp;Fred Tillman ,&nbsp;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}

{"title":"Investigation on the performance and mechanism of Cr(VI) immobilization with improved amorphous iron polysulfide: Batch experiments and numerical simulation","authors":"Kelin Zhang ,&nbsp;Danqing Liu ,&nbsp;Jinhao Yu ,&nbsp;Changzhong Xu ,&nbsp;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_x), which are more powerful than crystalline FeS_x 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_x is still unknown. In this paper, we synthesized efficient amorphous iron polysulfide (AIPS) with FeSO₄ and CaS_x 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_x 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. FeS_x (x &gt; 2), also as a reaction by-product of the Cr(VI) reduction by FeS and FeS₂, 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}