Applied Geochemistry最新文献

Estimation of thermodynamic properties for kerogen present in Boom Clay Boom Clay中干酪根热力学性质的估计

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-02-01 DOI: 10.1016/j.apgeochem.2025.106652

Laurent Richard , Sonia Salah, Delphine Durce, Norbert Maes

In Belgium, Boom Clay (BC) represents one of the potential host rocks considered for the disposal of high-level and/or long-lived radioactive waste. The latter corresponds to heat generating waste which during disposal and the thermal phase may affect the rock properties and porewater chemistry. In this respect, it has been shown by different authors that perturbations, such as oxidation and/or thermal stress may lead to the degradation of the organic matter, i.e. kerogen comprised in BC. Although many studies on the solid and also on the dissolved OM pools of Boom Clay have been performed in the past, a thermodynamic description of the Boom Clay kerogen (BCK) and its degradation (products) is still lacking. BCK subjected to oxidation or thermal stress may generate thermolabile components and lead to the release of oxygen-containing polar products, like carboxylic acids and phenols which may affect the transport behavior of some radionuclides and chemotoxic elements due to complexation. In addition to water-soluble compounds also CO₂ is formed by the thermal cracking of kerogen. Based on spectroscopic methods and pyrolysis experiments previously performed on isolated BCK, the organic compounds constituting its macromolecular structure (i.e. n-alkanes, branched alkanes, aromatic hydrocarbons and oxygen compounds) were identified. The latter and application of the so-called group contribution approach allowed to estimate the thermodynamic standard state properties of BCK at 25 °C and 1 bar. The derived thermodynamic properties enable to formalize the geochemical reactions described above, as well as calculation of stability relations for different kerogen compositions under physicochemical conditions of the BC formation.

在比利时，Boom Clay （BC）代表了一种潜在的寄主岩石，可以用来处理高放射性和/或长寿命的放射性废物。后者对应的是产热废物，在处理过程中和热相可能影响岩石性质和孔隙水化学。在这方面，不同的作者已经表明，扰动，如氧化和/或热应力可能导致有机物的降解，即BC中包含的干酪根。虽然过去对Boom Clay的固体和溶解OM池进行了许多研究，但对Boom Clay干酪根（BCK）及其降解（产物）的热力学描述仍然缺乏。BCK在氧化或热应力作用下可能产生热不稳定性成分，并导致含氧极性产物的释放，如羧酸和酚类，这些产物可能由于络合作用而影响某些放射性核素和化学毒性元素的转运行为。除水溶性化合物外，干酪根的热裂解也可形成二氧化碳。基于对分离的BCK进行的光谱方法和热解实验，鉴定了构成其大分子结构的有机化合物（即正构烷烃、支链烷烃、芳烃和含氧化合物）。后者和所谓的基团贡献法的应用允许估计BCK在25°C和1bar下的热力学标准态性质。推导出的热力学性质使上述地球化学反应形式化，并计算了BC地层物理化学条件下不同干酪根组成的稳定性关系。

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引用次数: 0

Application of the Keeling plot approach in quantifying sediment organic matter sources using carbon isotopes and C/N ratios: An example from Xiaowan Reservoir, Lancang River basin, China 基于碳同位素和碳氮比的基林样图法在沉积物有机质来源定量研究中的应用——以澜沧江流域小湾水库为例

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-02-01 DOI: 10.1016/j.apgeochem.2026.106703

Mingwei Guo , Shilu Wang , Kevin M. Yeager , Xiangfeng Han , Yuchun Wang , Shehong Li , Yufei Bao , Weiqi Lu , Zhenjie Zhao , Kun Liu , Jiaxi Wu

Partitioning autochthonous and allochthonous organic matter (OM) contributions to reservoir sediments is essential for accurately estimating the magnitude of carbon sequestration in reservoirs. The commonly used combination of C/N ratios and organic carbon isotopes (δ¹³C_OC) is often limited by poorly constrained end-member compositions, which hampers quantitative source apportionment. In this study, four sediment cores were collected from the Xiaowan Reservoir, a large and deep reservoir in the Lancang River basin, China. Total organic carbon (TOC), total nitrogen (TN), and δ¹³C_OC were measured to test the hypothesis that the Keeling plot approach can be used to localize the compositional values of sedimentary OM sources. To adapt the Keeling plot method to this multi-source system, a “dominant source” assumption was introduced. The resulting end-member compositions for terrestrial plant, algal, bacterial, and soil OM are consistent with previously reported values but exhibit substantially reduced uncertainty. Organic matter source apportionment using the MixSIAR Bayesian mixing model indicates that bacterial reworking represents the dominant contribution to sedimentary OM. The narrowed, site-specific end-member ranges derived from the Keeling plot approach demonstrate strong potential for resolving subtle spatial (horizontal) and temporal (vertical) variations in OM sources within reservoir sediments. Identifying appropriate sampling sites that satisfy the underlying assumptions of the method is therefore critical for its successful application.

划分原生和外来有机质对储层沉积物的贡献对于准确估计储层固碳量至关重要。常用的碳氮比和有机碳同位素（δ13COC）组合往往受到端元组成约束较差的限制，这阻碍了定量的来源分配。本研究收集了澜沧江流域大型深层水库小湾水库的4个沉积物岩心。通过测量总有机碳（TOC）、总氮（TN）和δ13COC，验证了基林图方法可用于沉积有机质源成分值定位的假设。为了使基林图法适用于多源系统，引入了“优势源”假设。陆生植物、藻类、细菌和土壤有机质的端元组成与先前报道的值一致，但不确定性大大降低。利用MixSIAR贝叶斯混合模型进行有机质来源分析表明，细菌改造是沉积有机质的主要来源。基林样地方法得到的狭窄的、特定地点的端元范围显示出强大的潜力，可以解决水库沉积物中OM源的微妙空间（水平）和时间（垂直）变化。因此，确定满足该方法基本假设的适当采样点对其成功应用至关重要。

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引用次数: 0

Fluid chemistry and isotopes for interpreting the formation of geothermal systems in the southern Qinghai-Xizang Plateau 青藏高原南部地热系统形成的流体化学和同位素解释

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-02-01 DOI: 10.1016/j.apgeochem.2026.106710

Xingze Li , Yuankang Zhong , Peng Zhou , Gongxi Liu , Hua Wu , Ying Wang , Xiaoyan Zhao , Xingcheng Yuan , Jinhang Huang , Yunhui Zhang

As a clean and renewable energy resource, geothermal energy significantly contributes to lowering carbon emissions and fostering sustainable development over the long term. This study investigates the genesis, hydrochemical evolution, and reservoir characteristics of geothermal waters in the Southern Qinghai−Xizang Plateau. 45 geothermal water samples were examined for their physicochemical properties, major ion concentrations, and stable isotope compositions (δD, δ¹⁸O). To categorize hydrochemical facies and identify the dominant geochemical processes, multivariate statistical techniques, including hierarchical cluster analysis (HCA), correlation analysis (CA), and principal component analysis (PCA) were applied. Two distinct hydrochemical clusters were identified: a Cl–Na type characterized by higher TDS and Cl⁻ concentrations, and an HCO₃–Na type with elevated bicarbonate levels. Isotopic data indicate meteoric recharge with significant oxygen isotope drift, and calculated recharge elevations suggest recharge primarily occurs between 2900 and 4533 m and 3767−4700 m, respectively. Water–rock interaction analysis reveals that silicate weathering, carbonate dissolution, cation exchange, and magmatic fluid input are the dominant processes shaping water chemistry. Geothermometric calculations using quartz and chalcedony solubility, combined with silica–enthalpy mixing models, indicate reservoir temperatures of 111–245 °C (Cl–Na type) and 102–224 °C (HCO₃–Na type), with circulation depths ranging from 1631 to 3692 m and 1492–3369 m, respectively. The genesis model proposed in this study suggests that both water types originate from deep thermal circulation systems with variable proportions of magmatic fluid input (Cluster 1: 10 %–26 %, average 19 %; Cluster 2: 6 %–28 %, average 15 %) and mixing with shallow cold groundwater. These findings provide a scientific basis for sustainable geothermal resource development and contribute to a better understanding of geothermal systems in complex tectonic settings of orogenic belts.

地热能作为一种清洁的可再生能源，对降低碳排放和促进长期可持续发展具有重要作用。为探讨青藏高原南部地热水的成因、水化学演化及储层特征，对45份地热水样品进行了理化性质、主要离子浓度和稳定同位素组成（δD、δ18O）的测定。应用层次聚类分析（HCA）、相关分析（CA）和主成分分析（PCA）等多元统计技术对水化学相进行分类，识别优势地球化学过程。确定了两种不同的水化学簇：以较高的TDS和Cl -浓度为特征的Cl - na型和碳酸氢盐水平升高的HCO3-Na型。同位素数据表明，大气补给具有明显的氧同位素漂移，计算的补给高度表明，补给主要发生在2900 ~ 4533 m和3767 ~ 4700 m之间。水岩相互作用分析表明，硅酸盐风化、碳酸盐溶蚀、阳离子交换和岩浆流体输入是形成水化学的主要过程。利用石英和玉髓溶解度进行的地热计算，结合二氧化硅-焓混合模型，表明储层温度为111 ~ 245℃（Cl-Na型）和102 ~ 224℃（HCO3-Na型），循环深度分别为1631 ~ 3692 m和1492 ~ 3369 m。本文提出的成因模型表明，这两种水类型都起源于深部热循环系统，岩浆流体输入比例不同（第一类：10% ~ 26%，平均19%；第二类：6% ~ 28%，平均15%），并与浅层低温地下水混合。这些发现为地热资源的可持续开发提供了科学依据，有助于更好地认识造山带复杂构造环境下的地热系统。

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引用次数: 0

Impacts of snow nitrate photolysis and recycling on identification of oxidation information recorded in nitrate in Antarctica 雪硝光解和再循环对南极硝酸盐氧化信息鉴定的影响

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-02-01 DOI: 10.1016/j.apgeochem.2026.106709

Xiaolong Li , Guitao Shi , Yilan Li , Danhe Wang , Ye Hu , Wendell W. Walters

The oxygen isotopes of nitrate (NO₃⁻), specifically δ¹⁸O(NO₃⁻) and Δ¹⁷O(NO₃⁻), provide insights into the oxidation mechanisms responsible for NO₃⁻ formation and reflect the atmospheric oxidation capacity. However, these isotopic signatures can be altered by post-depositional processes. This study collected data on NO₃⁻ nitrogen and oxygen isotopes in various samples, including snowpits, ice cores, snowfall, and skin layer snow, from different Antarctic regions. We observed a linear relationship between δ¹⁸O(NO₃⁻) and Δ¹⁷O(NO₃⁻) at each site, suggesting that NO₃⁻ production involves a mixture of oxidants such as O₃/XO, OH, and HO₂/RO₂, with O₃ identified as a key contributor. The δ¹⁸O values of other oxidants, termed as the derived δ¹⁸O, were obtained from this linear relationship at each site, excluding O₃, and showed a decreasing trend from the coast to inland region in Antarctica. We found that these derived δ¹⁸O values exhibited significant linear correlations with the reciprocal of the snow accumulation rate and δ¹⁸O(H₂O), indicating the differences in NO₃⁻ photolysis and recycling processes within snowpack across various sites. Additionally, we estimated the average photolysis-driven loss fraction of NO₃⁻ and its oxygen exchange fraction with H₂O, and found that both processes are more intense on the East Antarctic plateau and weaker in coastal regions, largely controlled by snow accumulation rate. At low accumulation sites, the derived δ¹⁸O values are more affected by local δ¹⁸O(H₂O), leading to modifications of the atmospheric oxidation signals recorded in the ice core NO₃⁻.

硝酸盐（NO3−）的氧同位素，特别是δ18O（NO3−）和Δ17O(NO3−)，提供了NO3−形成的氧化机制的见解，并反映了大气的氧化能力。然而，这些同位素特征可能会被沉积后的过程所改变。本研究收集了来自南极不同地区的各种样品（包括雪坑、冰芯、降雪和皮肤层雪）的NO3−氮和氧同位素数据。我们观察到每个位点的δ18O（NO3−）和Δ17O（NO3−）之间存在线性关系，这表明NO3−的生成涉及O3/XO、OH和HO2/RO2等氧化剂的混合物，其中O3被认为是关键的贡献者。除O3外，其他氧化剂的δ18O值均为推导δ18O值，均呈现由沿海向内陆递减的趋势。我们发现，这些δ18O值与积雪速率和δ18O（H2O）的倒数呈显著的线性相关，表明不同地点积雪中NO3−光解和再循环过程的差异。此外，我们估算了平均光解作用下NO3−的损失分数及其与H2O的氧交换分数，发现这两个过程在南极东部高原更强烈，在沿海地区较弱，主要受积雪速率控制。在低积累点，导出的δ18O值更多地受到当地δ18O（H2O）的影响，导致记录在冰芯NO3−中的大气氧化信号发生改变。

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引用次数: 0

GeoChemNet: An interactive tool for visualizing and interpreting outliers in geochemical data using networks GeoChemNet：利用网络可视化和解释地球化学数据异常值的交互式工具

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-01-28 DOI: 10.1016/j.apgeochem.2026.106712

Timothy C.C. Lui , Anirudh Prabhu , Anna Bidgood , Shaunna M. Morrison , Jef Caers

In this paper we introduce GeoChemNet as a novel tool for visualizing and analyzing high-dimensional geochemical datasets. Unlike traditional approaches such as principal component analysis and pairplots, GeoChemNet uses a non-linear methodology that does not require predefined number of elements, allowing it to reveal highly multidimensional anomalies that are not elucidated using other methods. We demonstrate its advantages using an artificial dataset and compare its performance to conventional techniques. We then apply the tool to two case studies from the same region. The first illustrates how GeoChemNet can work synergistically with clustering algorithms to uncover structure within lithological units. The second demonstrates its utility as a standalone tool for reducing the search space in mineral exploration of sediment-hosted copper deposits. Ultimately, GeoChemNet's interactive, geospatial visualizations enhance communication between geoscientists and data scientists and uncover geological insights from geochemical datasets.

本文介绍了GeoChemNet作为一种可视化和分析高维地球化学数据集的新工具。与主成分分析和配对图等传统方法不同，GeoChemNet使用非线性方法，不需要预定义的元素数量，从而可以揭示其他方法无法阐明的高度多维异常。我们使用人工数据集展示了它的优势，并将其性能与传统技术进行了比较。然后，我们将该工具应用于来自同一地区的两个案例研究。第一个例子说明了GeoChemNet如何与聚类算法协同工作，以揭示岩性单元内的结构。第二个例子证明了它作为一个独立工具的实用性，可以减少沉积型铜矿的矿产勘探搜索空间。最终，GeoChemNet的交互式地理空间可视化增强了地球科学家和数据科学家之间的沟通，并从地球化学数据集中揭示地质见解。

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引用次数: 0

Groundwater hydrogeochemical evolution and driving forces in a typical arid closed intermountain basin on Tibetan Plateau: a quantitative framework 青藏高原典型干旱封闭山间盆地地下水水文地球化学演化与驱动力：一个定量框架

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-01-21 DOI: 10.1016/j.apgeochem.2026.106711

Yong Xiao , Liwei Wang , Jie Wang , Xu Guo , Zhihong Zhang , Jiahua Wei , Zhen Zhao , Shaokang Yang , Huijuan Chen , Nuan Yang , Guangbin Zhu

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 <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 (>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.

地下水对维持干旱内河山间盆地的社会经济发展和生态健康具有至关重要的意义。然而，它的可用性受到水化学成分的严重限制，其数量仍然不充分。本文以青藏高原恰卡盆地为例，探讨了干旱内陆河流域地下水地球化学的空间格局、驱动力及其定量贡献。结果表明，地下水总体呈碱性，盐度具有较大的空间变异性。在山口附近，地下水保持新鲜（TDS <1 g/L），保留了从山源补给中继承的有利的水化学特征。盐度沿地下水流道逐渐增加，在中下游潜水含水层和承压含水层之间有明显的对比。潜水地下水的TDS较高（终端湖附近为10 g/L），而承压地下水在相同设置下仍保持相对新鲜，这主要是由于蒸发作用。水文地球化学成分主要由水岩相互作用组成，包括蒸发岩溶解（40.18%）、硅酸盐风化（16.31%）和氟化物矿物溶解/离子交换（13.08%）。人类活动，如农业实践（16.31%）和生活污水排放（13.41%），也发挥了相当大的作用。为了阐明地下水化学的空间格局和定量形成机制，建立了一个概念模型。这些发现为理解全球干旱内陆盆地水文地球化学演化和地下水质量有效性提供了系统框架。

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引用次数: 0

N2O emissions from two adjacent, seasonally stratified reservoirs in the Wujiang Basin: Influences of N addition and N managements 吴江盆地相邻两个季节性分层水库N2O排放：N添加和N管理的影响

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-01-20 DOI: 10.1016/j.apgeochem.2026.106702

Wuyan Wang , Qingguang Li , Weiqi Lu , Shangyi Gu

Anthropogenic nitrogen (N) loading significantly influences nitrous oxide (N₂O) emissions from freshwater ecosystems, but the effects of watershed N management on these emissions remain poorly quantified. This study investigated N₂O dynamics in two adjacent, seasonally stratified reservoirs, Hongfeng (HF) and Baihua (BH), in the Wujiang Basin, China, which share similar climatic and limnological conditions but experience different levels of anthropogenic N input. The downstream BH Reservoir, located closer to urban areas, received higher N loads, resulting in significantly higher nitrate (NO₃⁻) concentrations compared to the upstream HF Reservoir. Correspondingly, BH exhibited remarkably higher surface N₂O concentration and an estimated N₂O emission flux (20.0 μmol m² d⁻¹) approximately double that of HF (9.6 μmol m² d⁻¹). Historical data revealed that N₂O emissions peaked during periods of severe pollution (2003–2008) and declined following the implementation of watershed pollution abatement, demonstrating that effective nutrient control not only improves water quality but also materially mitigates N₂O emissions. The seasonal co-variation of N₂O with NH₄⁺ suggests that NH₄⁺ availability directly controls the short-term production rates, which accords the generally-accepted viewpoint that nitrification is the main pathway of N₂O production in reservoirs. On the other hand, NO₃⁻ influences the long-term baseline emission potential via phytoplankton-mediated recycling. These findings highlight that managing anthropogenic N inputs is crucial and effective for reducing N₂O emissions from deep reservoirs.

人为氮(N)负荷显著影响淡水生态系统的氧化亚氮（N2O）排放，但流域氮管理对这些排放的影响仍然缺乏量化。研究了吴江盆地两个相邻的季节性分层水库洪峰（HF）和白花（BH）的N2O动态，这两个水库具有相似的气候和湖泊条件，但经历了不同的人为N输入水平。BH水库下游靠近城市地区，受氮负荷较大，导致硝酸盐（NO3−）浓度明显高于上游HF水库。相应地，BH的表面N2O浓度显著高于HF (9.6 μmol m2 d - 1)， N2O发射通量（20.0 μmol m2 d - 1）约为HF的两倍。历史数据显示，N2O排放量在严重污染时期（2003-2008年）达到峰值，在实施流域污染治理后下降，表明有效的养分控制不仅可以改善水质，而且可以实质性地减少N2O排放。N2O与NH4+的季节共变表明，NH4+的有效性直接控制了短期产速率，这与普遍认为的硝化作用是水库N2O产的主要途径的观点一致。另一方面，NO3−通过浮游植物介导的再循环影响长期基线排放潜力。这些发现强调，管理人为N输入对于减少深层水库的N2O排放至关重要且有效。

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引用次数: 0

Groundwater age distribution in granular and fractured aquifers of the Laurentides region, Eastern Canada, to evaluate the resource sustainability 加拿大东部Laurentides地区颗粒状和裂缝状含水层的地下水年龄分布，以评估资源的可持续性

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-01-20 DOI: 10.1016/j.apgeochem.2026.106706

Samuel Bolduc , Daniele L. Pinti , Marie Larocque , Olfa Swaissi

Groundwater ages cannot be considered precise metrics for directly evaluating the sustainability of water resources. However, determining the age distribution enhances understanding of the entire hydrogeological system and, indirectly, contributes to the assessment of sustainability. The objective of this research was to evaluate how a combination of age tracers can contribute to estimating groundwater age distribution in large and complex aquifer systems. The system consists of fractured Grenvillian-age (≥ 1 Ga) aquifers, locally covered by granular postglacial Holocene aquifers in valley bottoms of the mountainous and hilly Laurentides region of southern Québec Province (Eastern Canada). The age tracers used in this study, ¹⁴C, ³H/³He, and U–Th/⁴He were measured on groundwater samples collected from 32 municipal wells and one piezometer, from five watersheds. As expected, mixed idealized ages were obtained. The ³H/³He ages varied from modern to 64 years. The ¹⁴C-corrected ages generally ranged from “modern” to 6500 years old. The U–Th/⁴He-computed ages were close to the ¹⁴C ages but were strongly dependent on local aquifer conditions, primarily on U and Th contents and porosity. Three “activity indexes” – A⁴He, A³H, and A¹⁴C representing groundwater aging recorded a common temporal evolution of groundwater, with increasing ages from the southernmost, more populated areas to the less populated areas in the northern portion of the study area. Lumped parameter models applied to ³H–¹⁴C and to radiogenic ⁴He–¹⁴C showed that the aquifers contain a mixture of “modern” and “pre-industrial” water (200–14,000 yrs), and possibly Late Pleistocene water (10–30 ka) in some confined areas. This research advances the understanding of regional hydrogeology, providing insights into how North America's glacial history has influenced the mixing of groundwater volumes of different ages, thereby affecting groundwater sustainability differently in a complex aquifer system.

地下水年龄不能被认为是直接评价水资源可持续性的精确指标。然而，确定年龄分布增强了对整个水文地质系统的了解，并间接有助于可持续性的评估。本研究的目的是评估年龄示踪剂的组合如何有助于估计大型复杂含水层系统中的地下水年龄分布。该系统由破碎的grenvillian时代（≥1 Ga）含水层组成，在加拿大东部qu省南部Laurentides地区的山地和丘陵山谷底部，局部被颗粒状的冰期后全新世含水层覆盖。本研究中使用的年龄示踪剂14C、3H/3He和U-Th /4He在五个流域的32口市政井和一个气压计中采集的地下水样本上进行了测量。正如预期的那样，得到了混合的理想年龄。3H/3He年龄从现代到64岁不等。经14c校正的年龄一般在“现代”到6500年之间。U - Th/ 4he计算年龄接近14C年龄，但与当地含水层条件密切相关，主要受U、Th含量和孔隙度的影响。代表地下水年龄的A4He、A3H和A14C三个“活度指数”记录了地下水的共同时间演化，从研究区最南端人口多的地区到北部人口少的地区，年龄逐渐增加。应用于3H-14C和放射性成因4He-14C的集总参数模型表明，含水层含有“现代”和“前工业”水（200 - 14000年）的混合物，在一些封闭区域可能含有晚更新世水（10 - 30ka）。这项研究促进了对区域水文地质学的理解，为了解北美冰川历史如何影响不同年龄地下水的混合，从而在复杂的含水层系统中不同地影响地下水的可持续性提供了见解。

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引用次数: 0

Contribution of dissolved organic carbon to total alkalinity in Enhanced Weathering experiments 增强风化试验中溶解有机碳对总碱度的贡献

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-01-20 DOI: 10.1016/j.apgeochem.2026.106685

Lukas Rieder , Mathilde Hagens , Reinaldy Poetra , Alix Vidal , Tullia Calogiuri , Anna Neubeck , Abhijeet Singh , Thomas Corbett , Harun Niron , Sara Vicca , Siegfried E. Vlaeminck , Iris Janssens , Tim Verdonck , Ivan Janssens , Xuming Li , Jens S. Hammes , Jens Hartmann

Total Alkalinity (TA) is widely used as a proxy for captured CO₂ in enhanced weathering (EW) applications. However, organic anions can also contribute to TA. To improve carbon accounting in EW, which is often simplified to that TA equals carbonate alkalinity, their contribution should be taken into account.

In this study, we tested how dissolved organic carbon (DOC) contributes to non-carbonate alkalinity (A_NC) using microcosm experiments with artificial organo-mineral mixtures. We used different combinations of rock powder with straw, microbes and earthworm additions, under ambient air conditions. The microcosms were flow-through columns placed in a climate chamber at 25 °C, which were irrigated with groundwater at rates between 1200 and 3600 mm/yr. The concentrations of several low-molecular-weight organic acids (oxalate, citrate, acetate, gluconate) were quantified to assess which conjugate base anions impact the measured TA.

Results revealed a ratio of 3.5 mol DOC per A_NC equivalent. In the overall experiment the median contribution of A_NC to TA was around 5.5 %. A positive correlation between DOC and charge-balance error suggests that some organic acid anions remained deprotonated during TA titration. Acetate anions found in DOC-rich water samples further support a substantial contribution of organic anions to TA. To investigate the relevance of A_NC for natural EW systems, we also quantified A_NC contributions in natural waters and leachates from soil EW experiment mesocosms. Because DOC levels were lower, A_NC contributions were smaller, ranging from a median of 4.1 % in soil mesocosm leachates down to 0.9 % in Elbe estuary water samples. This A_NC contribution, despite seeming small, is relevant for carbon accounting in terrestrial EW practices, where TA is often assumed to be solely carbonate alkalinity.

在增强风化（EW）应用中，总碱度（TA）被广泛用作捕获二氧化碳的代理。然而，有机阴离子也可以促进TA。为了改进EW中的碳核算，通常将其简化为TA等于碳酸盐碱度，应考虑它们的贡献。在本研究中，我们通过人工有机矿物混合物的微观实验，测试了溶解有机碳（DOC）对非碳酸盐碱度（ANC）的贡献。在环境空气条件下，我们使用了岩石粉与稻草、微生物和蚯蚓添加剂的不同组合。微型生物被放置在25°C的气候室中，用地下水以1200到3600毫米/年的速度灌溉。对几种低分子量有机酸（草酸、柠檬酸、乙酸、葡萄糖酸）的浓度进行了量化，以评估哪些共轭碱阴离子会影响测定的TA。结果显示，每ANC当量的比例为3.5 mol DOC。在整个实验中，ANC对TA的贡献中位数约为5.5%。DOC与电荷平衡误差之间的正相关表明，在TA滴定过程中，一些有机酸阴离子仍保持去质子化。在富含doc的水样中发现的醋酸阴离子进一步支持有机阴离子对TA的大量贡献。为了研究自然生态系统中ANC的相关性，我们还量化了自然水体和土壤生态系统渗滤液中ANC的贡献。由于DOC水平较低，ANC的贡献较小，从土壤中生态渗滤液的中位数4.1%到易北河口水样的0.9%不等。这种ANC的贡献，尽管看起来很小，但与陆地EW实践中的碳核算有关，其中TA通常被认为仅仅是碳酸盐碱度。

{"title":"Contribution of dissolved organic carbon to total alkalinity in Enhanced Weathering experiments","authors":"Lukas Rieder , Mathilde Hagens , Reinaldy Poetra , Alix Vidal , Tullia Calogiuri , Anna Neubeck , Abhijeet Singh , Thomas Corbett , Harun Niron , Sara Vicca , Siegfried E. Vlaeminck , Iris Janssens , Tim Verdonck , Ivan Janssens , Xuming Li , Jens S. Hammes , Jens Hartmann","doi":"10.1016/j.apgeochem.2026.106685","DOIUrl":"10.1016/j.apgeochem.2026.106685","url":null,"abstract":"<div><div>Total Alkalinity (TA) is widely used as a proxy for captured CO<sub>2</sub> in enhanced weathering (EW) applications. However, organic anions can also contribute to TA. To improve carbon accounting in EW, which is often simplified to that TA equals carbonate alkalinity, their contribution should be taken into account.</div><div>In this study, we tested how dissolved organic carbon (DOC) contributes to non-carbonate alkalinity (A<sub>NC</sub>) using microcosm experiments with artificial organo-mineral mixtures. We used different combinations of rock powder with straw, microbes and earthworm additions, under ambient air conditions. The microcosms were flow-through columns placed in a climate chamber at 25 °C, which were irrigated with groundwater at rates between 1200 and 3600 mm/yr. The concentrations of several low-molecular-weight organic acids (oxalate, citrate, acetate, gluconate) were quantified to assess which conjugate base anions impact the measured TA.</div><div>Results revealed a ratio of 3.5 mol DOC per A<sub>NC</sub> equivalent. In the overall experiment the median contribution of A<sub>NC</sub> to TA was around 5.5 %. A positive correlation between DOC and charge-balance error suggests that some organic acid anions remained deprotonated during TA titration. Acetate anions found in DOC-rich water samples further support a substantial contribution of organic anions to TA. To investigate the relevance of A<sub>NC</sub> for natural EW systems, we also quantified A<sub>NC</sub> contributions in natural waters and leachates from soil EW experiment mesocosms. Because DOC levels were lower, A<sub>NC</sub> contributions were smaller, ranging from a median of 4.1 % in soil mesocosm leachates down to 0.9 % in Elbe estuary water samples. This A<sub>NC</sub> contribution, despite seeming small, is relevant for carbon accounting in terrestrial EW practices, where TA is often assumed to be solely carbonate alkalinity.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106685"},"PeriodicalIF":3.4,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024054","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}

引用次数: 0

Sustainable removal of arsenic and mercury via integrated phytoremediation and biomass valorization of Eichhornia crassipes 通过综合植物修复和生物量增值持续去除砷和汞

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-01-19 DOI: 10.1016/j.apgeochem.2026.106699

Rashmi Ranjan Mandal, Deep Raj

Phytoremediation using Eichhornia crassipes was assessed as a sustainable strategy for the removal and stabilization of arsenic (As) and mercury (Hg) from contaminated aquatic systems, followed by the conversion of harvested biomass into biochar to enhance long-term metal immobilization. The study assessed plant performance under two different contamination levels (1 and 5 mg L⁻¹) to understand concentration-dependent responses. At the lower concentration, E. crassipes achieved high removal efficiencies, arrive at 93 % As and 87 % Hg reduction within 30 days. However, the removal decreased significantly at 5 mg L⁻¹, with efficiencies dropping to 76 % for As and 52 % for Hg, indicating physiological limitations and reduced uptake capacity under higher metal stress. Morphological and spectroscopic study revealed significant structural alterations in plant tissues and showed the accumulation of As and Hg within cellular sections, validating the plant's role as an effective accumulator species. To ensure safe post-harvest handling and prevent secondary contamination, the metal-enriched biomass was subjected to pyrolysis. The resulting biochar showed strong retention of both metals, attributed to its carbonaceous structure and enhanced binding sites formed during thermal transformation. This stable biochar demonstrated clear potential for long-term immobilization and reduced metal mobility. Overall, the integrated process combining phytoremediation with biomass valorization offers an eco-friendly, cost-effective, and circular approach for mitigating toxic metal contamination in water bodies. The outcomes highlight the double benefit of pollutant removal and the production of a value-added material, improving the applicability of E. crassipes in sustainable environmental management.

利用石竹进行植物修复被评估为一种可持续的策略，用于从受污染的水生系统中去除和稳定砷（as）和汞（Hg），然后将收获的生物质转化为生物炭，以增强长期的金属固定化。该研究评估了植物在两种不同污染水平（1和5 mg L−1）下的表现，以了解浓度依赖性反应。在较低的浓度下，石楠草具有较高的去除效率，在30天内达到93%的砷和87%的汞的还原。然而，当浓度为5 mg L−1时，砷的去除率显著下降，砷的去除率降至76%，汞的去除率降至52%，这表明在较高的金属胁迫下，砷的吸收能力受到生理限制和降低。形态学和光谱研究显示，植物组织结构发生了显著变化，并在细胞切片中发现了砷和汞的积累，证实了植物作为有效的积累物种的作用。为了确保收获后的安全处理和防止二次污染，对富含金属的生物质进行了热解处理。由于其碳质结构和热转化过程中形成的增强的结合位点，所得到的生物炭表现出很强的两种金属的保留。这种稳定的生物炭显示出长期固定和降低金属迁移率的明显潜力。总的来说，植物修复与生物质增值相结合的综合过程为减轻水体中的有毒金属污染提供了一种生态友好、经济有效和循环的方法。研究结果强调了去除污染物和生产增值材料的双重效益，提高了棘草在可持续环境管理中的适用性。

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引用次数: 0