Applied Geochemistry最新文献

{"title":"Behaviour of Mo(VI), Eu(III) and U(VI) in calcium-silicate-hydrate phases: Immobilisation and dynamic remobilisation under repository-relevant conditions","authors":"Aaron Haben,&nbsp;Nico Bachmann,&nbsp;Jan Jakob Langer,&nbsp;Ralf Kautenburger","doi":"10.1016/j.apgeochem.2026.106684","DOIUrl":"10.1016/j.apgeochem.2026.106684","url":null,"abstract":"<div><div>Calcium-silicate-hydrate (C–S–H) phases play an essential role as a geotechnical barrier in high-level nuclear waste (HLW) repositories. To guarantee the long-term safety of a HLW disposal site, it is important to know how and to which degree radionuclides are retained by C–S–H phases. To this date, only little to no data on the remobilisation dynamics of the repository-relevant elements Mo(VI), Eu(III) and U(VI) under realistic conditions are available. In this study, C–S–H phases incorporating these elements were synthesised, the element immobilisation was quantified via ICP-QQQ and their structure was investigated via X-ray diffractometry. All C–S–H phases had a calcium-silicon ratio (C/S) of 1.066 ± 0.003 and no relevant structural influences of the studied elements could be observed. In all cases, quantitative immobilisation was observed for Eu(III) and U(VI), whereas Mo(VI) was retained/incorporated to only about 50 %. Afterwards, their leaching behaviour with ultrapure water was studied in batch and mini-column experiments (MCE). Mo(VI) was remobilised quickly, while Eu(III) and U(VI) were retained nearly quantitatively. Due to the more realistic and therefore more representative conditions, further experiments to investigate the effects of three repository-relevant parameters were conducted only using MCE. A higher ionic strength significantly enhanced U(VI) remobilisation, while Eu(III) and Mo(VI) remained nearly unaffected. The displacement agents Fe(III) and Tb(III) only affected Mo(VI)'s remobilisation by retarding it. The addition of a complexing agent (2-phosphonobutane-1,2,4-tricarboxylic acid; PBTC) led to a delayed remobilisation of Mo(VI), while Eu(III) and U(VI) were remobilised to some degree after sufficient PBTC eluation. Overall, this work delivers important information on key processes relevant to nuclear waste disposal.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106684"},"PeriodicalIF":3.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923855","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":"Compositions and hydrocarbon generation potentials of Scrippsiella trochoidea under increasing temperature","authors":"Wei Cao ,&nbsp;Xianglan Kong ,&nbsp;Jingdong Mao ,&nbsp;Jianfang Hu ,&nbsp;Yong Ran","doi":"10.1016/j.apgeochem.2026.106679","DOIUrl":"10.1016/j.apgeochem.2026.106679","url":null,"abstract":"<div><div>Rising global temperature is exerting a notable effect on the photosynthetic process of marine algae, which in turn may affect the structure and distribution of marine primary producers on a global scale. Sea surface temperature exerts a multifaceted influence on the growth, composition and structure of dinoflagellate, as well as on inorganic carbon fixation. This paper investigates the effect of temperature change on the growth of one dinoflagellate specie <em>Scrippsiella trochoidea</em>, and examines the variations in the organic carbon structure of its cell wall. This study is pioneering in its exploration of the impact of temperature on the structural organisation of organic matter in the dinoflagellate, with a particular focus on methylene carbon. The results indicate that <em>Scrippsiella trochoidea</em> exhibits a propensity to synthesise elevated levels of aliphatic compounds and proteins, particularly long-chain aliphatic biopolymers, at elevated incubation temperature. Moverover, a highly positive correlation is identified between the incubation temperature and the methylene carbon structure in the alkyl carbon structure. Such compositional and structural changes can have a significant impact on the potential yield of oil and gas through the process of algal pyrolysis.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106679"},"PeriodicalIF":3.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024055","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":"Dissolved lithium content and aqueous geochemistry of the Haynesville Shale of East Texas and Northwest Louisiana","authors":"Jean-Philippe Nicot,&nbsp;Lucy T. Ko,&nbsp;Roxana Darvari,&nbsp;Brent A. Elliott","doi":"10.1016/j.apgeochem.2026.106707","DOIUrl":"10.1016/j.apgeochem.2026.106707","url":null,"abstract":"<div><div>We describe dissolved lithium content of water produced from the Haynesville Shale, a low-permeability, gas-producing formation of Jurassic age overlying the lithium-rich and stratigraphically close Smackover Formation. The 57 water samples and 5 rock samples were analyzed for major and minor elements and for stable water isotopes, and Li and Sr isotopes (selected samples). The samples show an average of 71.7 mg/L Li (16–125 mg/L range) for an average TDS of 126.7 g/L (55–206 g/L range). They also show that the Haynesville and Smackover dissolved lithium have distinct diagenetic pathways with a large gap in δ⁷Li values (3.27 ‰, n = 7 and 10.20 ‰, n = 4, respectively). However, δ⁷Li of Haynesville produced water and rock (−4.03 ‰, n = 5) are consistent with fractionation of lithium partitioned into clay minerals relative to the resident water. The Haynesville Shale strontium isotope ⁸⁷Sr/⁸⁶Sr ratio (0.70830, n = 5) is higher than that of the time-period sea (0.7070), and consistent with a clastic ⁸⁷Sr increase in a closed system, but lower than that of the published Arkansas carbonate-rich Upper Smackover values (0.70895, n = 72), which denotes a stronger clastic influence there. Water isotopes confirm that the samples represent formation water and have been little impacted by hydraulic fracturing or water condensation during sampling. However, low water production combined with marginal Li concentrations does not make the Haynesville Shale a primary target for lithium production.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106707"},"PeriodicalIF":3.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024124","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":"Influences of microplastic-dissolved organic matter-arsenic interactions on arsenic fate in geogenic contaminated groundwater: Mechanistic insights from kinetic-thermodynamic investigations and modeling","authors":"Yaping Zhang ,&nbsp;Kunfu Pi ,&nbsp;Xianjun Xie ,&nbsp;Ziyi Xiao ,&nbsp;Jianbo Shi ,&nbsp;Qianyong Liang ,&nbsp;Yuxia Li","doi":"10.1016/j.apgeochem.2026.106704","DOIUrl":"10.1016/j.apgeochem.2026.106704","url":null,"abstract":"<div><div>Arsenic (As) mobility and fate in geogenic contaminated groundwater can be impacted by co-occurring microplastics and dissolved organic matter (DOM). However, molecular mechanisms and kinetic constraints underlying microplastics-DOM-As interactions remain to be deciphered. By employing polystyrene microplastics (PSMPs) as a representative type of microplastics found in Datong high-As groundwater (As &gt;10 μg/L), this research investigated thermodynamically and kinetically adsorption of As(III) and As(V) by microplastics as well as the critical effects of DOM. At groundwater pH of 6.8, adsorption of both As species occurred via oxygen-containing functional groups on PSMPs surfaces, but As(V) adsorption was quicker and greater than As(III) due to macrocolloids-like nature of PSMPs. Humic acids (HA) and fulvic acids (FA) compete for adsorption sites, alter surface properties, and facilitate aggregation of PSMPs, thereby reducing available surface sites for As binding. Interactions among PSMPs, HA/FA, and As species lead to formation of complexes including PSMPs-FA/HA-As and FA/HA-As. Furthermore, HA and FA can change the diffusion coefficients and boundary layer thickness of As within PSMPs pores to alter adsorption kinetics. Our results provide novel mechanistic insights into joint roles of PSMPs and DOM in As mobilization/immobilization dynamics within geogenic contaminated groundwater. Moreover, this research consolidates theoretical foundation for understanding influences of emerging contaminants on environmental geochemical behaviors of geogenic As in pumped aquifers.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106704"},"PeriodicalIF":3.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024059","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 hydrogeochemical evolution and driving forces in a typical arid closed intermountain basin on Tibetan Plateau: a quantitative framework","authors":"Yong Xiao ,&nbsp;Liwei Wang ,&nbsp;Jie Wang ,&nbsp;Xu Guo ,&nbsp;Zhihong Zhang ,&nbsp;Jiahua Wei ,&nbsp;Zhen Zhao ,&nbsp;Shaokang Yang ,&nbsp;Huijuan Chen ,&nbsp;Nuan Yang ,&nbsp;Guangbin Zhu","doi":"10.1016/j.apgeochem.2026.106711","DOIUrl":"10.1016/j.apgeochem.2026.106711","url":null,"abstract":"<div><div>Groundwater is of paramount significance for sustaining the socio-economic development and ecological health of arid endorheic intermountain basins. However, its availability is severely limited by hydrochemical composition, which remains inadequately quantified. This study takes the Chaka Basin on the Tibetan Plateau as an example to elucidate the spatial patterns, driving forces, and their quantitative contributions of groundwater geochemistry in such arid endorheic basins. Results indicate that groundwater is generally alkaline with substantial spatial variability in salinity. Near the mountain pass, groundwater remains fresh (TDS &lt;1 g/L), retaining favorable hydrochemical characteristics inherited from mountain-sourced recharge. Salinity increases progressively along the groundwater flow path, with a notable contrast between phreatic and confined aquifers in the middle-lower reaches. Phreatic groundwater shows high TDS (&gt;10 g/L near the terminal lake), while confined groundwater remains relatively fresh under the same settings, largely due to evaporation. Hydrogeochemical compositions are predominantly contributed by water–rock interactions, including evaporite dissolution (40.18 %), silicate weathering (16.31 %), and fluoride mineral dissolution/ion exchange (13.08 %). Human activities, such as agricultural practices (16.31 %) and domestic sewage discharge (13.41 %), also exert considerable contributions. A conceptual model was developed to elucidate the spatial patterns and quantitative formation mechanisms of groundwater chemistry. These findings provide a systematic framework for understanding the hydrogeochemical evolution and availability of groundwater quality in arid endorheic basins worldwide.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106711"},"PeriodicalIF":3.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024121","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":"The impact of a NaNO3 plume in a deep geological repository on the diffusion of dissolved gases in clay","authors":"Elke Jacops ,&nbsp;Chloé Roonacker ,&nbsp;Hannes Claes ,&nbsp;Lander Frederickx ,&nbsp;Anneleen Vanleeuw ,&nbsp;Quoc Tri Phung ,&nbsp;Jerry Peprah Owusu ,&nbsp;Sergey V. Churakov ,&nbsp;Jon Harrington ,&nbsp;Andrew Wiseall ,&nbsp;Christophe Bruggeman","doi":"10.1016/j.apgeochem.2026.106681","DOIUrl":"10.1016/j.apgeochem.2026.106681","url":null,"abstract":"<div><div>In the framework of the geological disposal of high and intermediate-level long-lived radioactive waste, the Boom Clay is considered as a potential host formation in Belgium. Boom Clay has suitable characteristics that limit the mass transport of dissolved species. Since gas generation in geological repositories is unavoidable, its dissipation needs to be evaluated. This study focuses on the gas diffusion properties in the case of a geochemical perturbation of the near field of Boom Clay, caused by NaNO₃ leaching from Eurobitumen bituminised waste. The diffusion of 4 gases (He, CH₄, Xe, and C₂H₆) was measured in intact and chemically (with NaNO₃) disturbed samples and the change in diffusion coefficients after perturbation was assessed. Intact and disturbed samples were petrographically and petrophysically characterised. Results of this study show that most of the clay properties are not altered by the chemical perturbation. The parameter which changed significantly is the specific surface area, which decreased 40–60 % in the chemically disturbed samples. Water transport (hydraulic conductivity) is not influenced by the perturbation. For diffusivity of dissolved gases and HTO, the differences are not significant as they are within the uncertainty boundaries. Molecular dynamics simulations in montmorillonite revealed that the clay interlayer might potentially shrink or even collapse due to the chemical and osmotic potential differences induced by geochemical perturbation (NaNO₃). The reduced volume of the interlayer porosity did not impact the diffusion of dissolved gases. The key message of this study is that a perturbation of clay with 1 M NaNO₃ will not significantly alter the transport properties of dissolved gases in the near field. This information is of relevance for the development of a geological disposal concept of bituminised waste in Boom Clay.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106681"},"PeriodicalIF":3.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923924","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":"HyPiT: A thermodynamic database for modeling geochemical systems up to high temperatures, pressures and salinities","authors":"Arnault Lassin ,&nbsp;Christophe Chiaberge ,&nbsp;Sylvain Guignot ,&nbsp;Johann Tuduri ,&nbsp;Laurent André","doi":"10.1016/j.apgeochem.2026.106727","DOIUrl":"10.1016/j.apgeochem.2026.106727","url":null,"abstract":"<div><div>Modeling water-rock interactions in underground environments requires the use of thermodynamic databases that account for the complexity of groundwater chemical compositions under relevant pressure and temperature conditions. A key issue concerning saline groundwaters is their high ionic strength, which are often not reliably calculated and calls for the use of specific thermodynamic approaches. Among such approaches, the Pitzer model appears to be one of the most promising. However, its applicability to underground fluids is limited by the fact that the values of its numerous parameters are only known for a subset of chemical systems and, more particularly, are often missing for trace elements and at temperatures other than 25 °C. This paper describes a new way to develop a relevant thermodynamic database to account for the trace elements in these types of deep environments. It combines two in-house databases: Thermoddem, which relies on the B-dot Extended Debye-Hückel activity model, and PhreeSCALE, which uses the Pitzer formalism. The resulting <u>Hy</u>brid <u>Pi</u>tzer-<u>T</u>hermoddem (HyPiT) thermodynamic database (TDB) integrates a simplified Pitzer model to account for major and trace elements. Based on a series of recent works (Simoes et al., 2016, 2017a, 2017b), the Pitzer binary interaction parameters, <em>β</em>⁽⁰⁾ and <em>β</em>⁽¹⁾ and their first derivative with respect to temperature (d<em>β</em>⁽⁰⁾/dT and d<em>β</em>⁽¹⁾/dT) are determined for simulating the first order interactions between trace elements and major species. The HyPiT database is successfully applied to different geochemical systems relevant to underground environments. They include (i) the solubility of gypsum in NaCl and sea-type brines of varying ionic strength at temperatures between 0 and 25 °C, (ii) the solubility of barite in NaCl brines at 25, 60 and 80 °C, (iii) the solubility of calcite in 0.1 and 4 M NaCl brines for temperatures and pressures up 250 °C and 1450 bars, respectively, (iv) the solubility of amorphous silica up to 150 °C in various single electrolyte solutions, namely HCl, NaCl, MgCl₂, HNO₃, NaNO₃, Na₂SO₄, and MgSO₄. Particular attention is also given to the modeling of iron-bearing systems such as the speciation of Fe^III in LiCl solutions up to 20 mol/kg.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"199 ","pages":"Article 106727"},"PeriodicalIF":3.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171459","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":"Age-dependent cementitious leachate effects on metal and radionuclide sorption to sediments from a subsurface waste-disposal site","authors":"Peng Lin ,&nbsp;Karah Greene ,&nbsp;Wei Xing ,&nbsp;Steven Simner ,&nbsp;Christina Logan ,&nbsp;Richard Henry ,&nbsp;Daniel I. Kaplan","doi":"10.1016/j.apgeochem.2026.106701","DOIUrl":"10.1016/j.apgeochem.2026.106701","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Risk assessment to evaluate long-term disposal for heavy metal and radioactive constituents at the subsurface engineered disposal facilities rely on distribution coefficients (&lt;em&gt;K&lt;/em&gt;&lt;sub&gt;&lt;em&gt;d&lt;/em&gt;&lt;/sub&gt; &lt;em&gt;=&lt;/em&gt; &lt;em&gt;C&lt;/em&gt;&lt;sub&gt;&lt;em&gt;solid&lt;/em&gt;&lt;/sub&gt;&lt;em&gt;/C&lt;/em&gt;&lt;sub&gt;&lt;em&gt;liquid&lt;/em&gt;&lt;/sub&gt;). Low-level solid and liquid radioactive waste is disposed in the subsurface environment using various cementitious engineered barriers. This study measured &lt;em&gt;K&lt;/em&gt;&lt;sub&gt;&lt;em&gt;d&lt;/em&gt;&lt;/sub&gt; values to quantify the sorption–including adsorption, absorption, and/or precipitation for multiple metals/radionuclides in subsurface sediments impacted by cementitious leachates representing different cement aging stages, experimentally introduced as Cs(I), Sr(II), Ni(II), Eu(III), Th(IV), U(VI), Cr(VI), and Tc(VII), serving as chemical analogs of different chemical groups. Simulated groundwater (Stage IV) was used as a baseline besides three leachate simulants: freshly made concrete leachate (Stage I), portlandite (Stage II), and calcite (Stage III) to calculate the cementitious leachate impact factor (&lt;em&gt;f&lt;/em&gt;&lt;sub&gt;CementLeach&lt;/sub&gt;), defined as &lt;em&gt;K&lt;/em&gt;&lt;sub&gt;&lt;em&gt;d&lt;/em&gt;&lt;/sub&gt;-CementLeach/&lt;em&gt;K&lt;/em&gt;&lt;sub&gt;&lt;em&gt;d&lt;/em&gt;&lt;/sub&gt;-groundwater. Results showed significant changes in sorption between groundwater and leachate simulants. Monovalent cation analog Cs exhibited &lt;em&gt;K&lt;/em&gt;&lt;sub&gt;&lt;em&gt;d&lt;/em&gt;&lt;/sub&gt; values of 28–2390 L/kg (sandy) and 84–4230 L/kg (clayey), with &lt;em&gt;f&lt;/em&gt;&lt;sub&gt;CementLeach&lt;/sub&gt; up to 62 in sandy sediments impacted by young grout leachate. Divalent cations (Ni and Sr) and trivalent/tetravalent cations (Eu, Th) also showed strong enhancements in high-pH cementitious leachate environments; for example, Eu &lt;em&gt;K&lt;/em&gt;&lt;sub&gt;&lt;em&gt;d&lt;/em&gt;&lt;/sub&gt; increased from 25 L/kg in Stage IV groundwater to &gt;67000 L/kg in leachates. Tetravalent cation analog Th showed very strong sorption (&gt;10000 L/kg) in young and aged leachates, consistent with prior trivalent cation trends (Eu). Enhanced retention of multivalent cations (e.g., Ni&lt;sup&gt;2+&lt;/sup&gt;, Eu&lt;sup&gt;3+&lt;/sup&gt;, Th&lt;sup&gt;4+&lt;/sup&gt;, and UO&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;2+&lt;/sup&gt;) in cementitious leachate-impacted sediments reflects not only surface sorption processes but also precipitation under elevated pH conditions, particularly in young grout leachate environments. Such precipitation-driven mechanisms were not evident for Cs&lt;sup&gt;+&lt;/sup&gt;. Across cement aging stages, enhanced (Stage III) and/or reduced sorption (Stage II) can be observed for anionic species CrO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2−&lt;/sup&gt;, while &lt;sup&gt;99&lt;/sup&gt;TcO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;, a key risk driver, displayed minimal sorption and negligible response to cementitious leachates. These results represent the first extensive dataset quantifying cementitious leachate effects on sorption to sediments for different types of cation and anion metal contaminants. It also underscores how the evolution of cementitious barriers reshapes groundwater chemistry, directly influencing the predicted mobil","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106701"},"PeriodicalIF":3.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974370","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":"Predicting the kinetics of Cu release and transport in contaminated soils in the field","authors":"Liang Dong ,&nbsp;Rong Li ,&nbsp;Wenxia Wang ,&nbsp;Zhifang Xiao ,&nbsp;Zezhen Ren ,&nbsp;Qianting Ye ,&nbsp;Zhenqing Shi","doi":"10.1016/j.apgeochem.2026.106698","DOIUrl":"10.1016/j.apgeochem.2026.106698","url":null,"abstract":"<div><div>Accurately predicting heavy metal release from contaminated soils remains challenging because of heterogeneous sorption sites, dynamic organic-matter turnover, and transient hydrological forcing. Here we develop a unified multi-process kinetics model that couples multi-site adsorption–desorption, vertically resolved dissolved organic carbon (DOC) dynamics, and water flow–solute transport to simulate copper (Cu) release in two contaminated field sites during rainfall events. We further accelerate the numerical solver with a machine-learning surrogate model, achieving more than 100-fold speed-up. Rainfall–evaporation experiments at two Cu-contaminated soils with contrasting textures and contamination levels showed that less than 5 % of total Cu was labile, and that soil organic matter dominated Cu binding. The model reproduced depth-resolved dissolved Cu profiles with symmetric mean absolute percentage errors of 26–30 %, by capturing rainfall-driven dilution, adsorption–desorption kinetics, and DOC-mediated mobilization. Our results show that short-term Cu mobility is controlled primarily by its labile fraction rather than total concentration, and that coupling carbon cycling with hydrodynamics is essential for field-scale predictions. This transferable modeling framework enables mechanistic and site-specific forecasts of heavy-metal fate under diverse and changing environmental conditions.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106698"},"PeriodicalIF":3.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974858","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 sediment quality guidelines and geochemical indices to evaluate the impact of trace metals on sediments from a fish farming area in the Rosário reservoir, Brazil","authors":"Hênio do Nascimento Melo Júnior ,&nbsp;Francisco José de Paula Filho ,&nbsp;Jorge Marcel Coelho Menezes ,&nbsp;Henrique Douglas Melo Coutinho ,&nbsp;Raimundo Nonato Pereira Teixeira ,&nbsp;Hênio Vitor Sobral Melo","doi":"10.1016/j.apgeochem.2026.106726","DOIUrl":"10.1016/j.apgeochem.2026.106726","url":null,"abstract":"<div><div>The expansion of global aquaculture includes, among other techniques, net-pen fish farming in semiarid regions, where studies remain scarce. This study assessed the sediment geochemistry of the Rosário Reservoir in Brazil, aiming to assess the influence of net-pen aquaculture on sediment quality. Sampling was conducted in control (CTRL), cultivation (CTV), and post-cultivation (PCTV) areas, with 10 replicates each. Tests included particle size distribution, organic matter content, trace metals (Fe, Mn, Zn, Cu, Cr, Cd, Pb, and Ni), sediment quality guidelines, multivariate statistics (Pearson's correlation, similarity analysis, and principal component analysis), and geochemical indices (Contamination Factor, Pollution Load Index, Nemerow Pollution Index, and Combined Pollution Index). Sediments were determined to be clayey–silty loam, with an organic matter content of 18.76 ± 4.27%. The highest metal concentrations occurred in the CTV (Fe, Mn, Zn, and Cr) and PCTV (Cd, Cu, Pb, and Ni) areas, with Ni exceeding sediment quality thresholds. The multivariate testing shows that aquaculture is a source of metals and organic matter. Geochemical indices revealed mostly low to moderate pollution, with localized polluted conditions. Overall, fish farming had a limited impact on trace metal accumulation. The methodological framework proved effective for environmental monitoring and management, supporting both qualitative and quantitative assessments of aquaculture-related impacts.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"199 ","pages":"Article 106726"},"PeriodicalIF":3.4,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171463","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}