Effects of Fe oxides on organic carbon variation in the evolution of clayey aquitard and environmental significance

Liu, Rui; Ma, Teng; Qiu, Wenkai; Du, Yao; Liu, Yanjun

doi:10.1016/j.scitotenv.2019.134776

Cited by 22 publications

(4 citation statements)

References 44 publications

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“…Small molecule organic carbon and CO 2 generated by OM mineralization become the sources of DOC and DIC in pore water [12]. The significant positive correlations between DOC, DIC, and Fe 2+ concentrations confirm the importance of OM in Fe (III) reduction dissolution (Table 3).…”

Section: Vertical Distribution and Environmental Factors Influencing ...mentioning

confidence: 65%

“…Based on the test results of EEM, the pore water DOM in borehole C1 was all humic-like OM under long-term humification (Figure 7). The appearance of protein-like DOM fluorophores in surface pore water samples from boreholes C2 and C3 suggest that cultivated crops present incompletely humified OM to the clay layer, which could be preferentially utilized by microorganisms to provide electrons for Fe reduction [12]. As a result of the OM input from the cultivated crops, borehole C3 had higher average levels of TOC (Table 2) and DOC (C1: 8.84, C2: 9.55, C3: 14.83 mg/L) above −3 m than boreholes C1 and C2, which might promote the enrichment of pore water Fe ions.…”

Section: Effect Of Reclamation On Fe Occurrence In Clayey Aquitardmentioning

confidence: 99%

“…Fe is one of the terminal electron receptors of microbial reactions, facilitating the migration and transformation of other essential elements (such as carbon, nitrogen, phosphorus, etc.) [12][13][14][15]. The reductive dissolution of Fe (hydrogen) oxides is an important process for the release of Fe-bound contaminants such as heavy metals [16,17].…”

Section: Introductionmentioning

confidence: 99%

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Spatial Distribution and Factors Influencing the Various Forms of Iron in Alluvial–Lacustrine Clayey Aquitard

Chen,

Liu,

Jian

et al. 2023

Water

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The compression release of pore water in clayey aquitards has a significant impact on groundwater quality. Iron is an active variable element that mediates biochemical reactions in groundwater systems, but its transformation mechanisms in clayey aquitards remain unclear. The sediment and pore water samples from the shallow clayey aquitard (thickness = ~20 m) in the Chen Lake area of China were collected in three boreholes. The spatial distribution and influencing factors of Fe occurrence in the aquitard were revealed using hierarchical extraction, statistical analysis, and simulation calculations. The results indicate that the background value of alluvial–lacustrine sediments primarily affects the Fe concentration of clayey sediments. The dissimilatory reduction in free Fe oxide was the main source of Fe ions in pore water, resulting in a major percentage of Fe2+ in the total Fe concentration (0.07−5.91 mg/L). The abundant organic matter in organic-rich clay promoted a dissimilatory reduction in Fe (III) oxides, while the Fe concentrations of sediment and pore water were lower in the sand-rich stratum because of its weak adsorption capacity. The impact of human reclamation activities on the aquitard was mainly concentrated in the shallow layer (>−3 m), resulting in water drainage and O2 and CO2 input, which induced the crystallization of poorly crystalline Fe oxides. The input of reactive organic matter from reclaimed crops promoted the dissimilatory reduction in Fe oxides and the enrichment of Fe in deep pore water. The copious Fe2+ in deep stratum pore water tended to interact with CO32− and S2− to form coprecipitation with Fe (II). The concentrations of As, Cr, Sr, Zn, and Mn in pore water followed a similar variation trend to the Fe ion concentration, and their release could be attributed to the reduction dissolution of sediment Fe (III) oxides.

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Section: Vertical Distribution and Environmental Factors Influencing ...mentioning

confidence: 65%

Section: Effect Of Reclamation On Fe Occurrence In Clayey Aquitardmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spatial Distribution and Factors Influencing the Various Forms of Iron in Alluvial–Lacustrine Clayey Aquitard

Chen,

Liu,

Jian

et al. 2023

Water

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“…Various models of mobilization processes have been proposed to explain the elevated geogenic P concentrations in groundwater. − However, there is a consensus that microbe-mediated degradation/oxidation of P-containing sedimentary or dissolved organic matter (OM) and reductive dissolution and desorption from P-bearing Fe(III) (oxyhydr)oxides (FeOOH) play key roles in the genesis of geogenic P-rich groundwater. ,, Therefore, OM and FeOOH are the most important factors controlling geogenic P enrichment, especially in alluvial-lacustrine plains, where subsurface OM and FeOOH are abundant. , However, even considering these two most critical factors only, understanding the sources and enrichment mechanisms about geogenic P is not straightforward, particularly because of (i) the complex occurrences of various OM types with different reactivities, various FeOOH phases with different crystallinities, and various P pools associated with different hosting phases and (ii) the variable strategies for geogenic P enrichment via oxidation of OM with different reactivities coupled to reductive dissolution of FeOOH with different crystallinities. , Thus, systematic characterizations (about OM, FeOOH, and P) and detailed analysis (about variable strategies) are key to understanding the fate of P in groundwater systems.…”

Section: Introductionmentioning

confidence: 99%

Coupled Processes Involving Organic Matter and Fe Oxyhydroxides Control Geogenic Phosphorus Enrichment in Groundwater Systems: New Evidence from FT-ICR-MS and XANES

Tao,

Du,

Deng

et al. 2023

Environ. Sci. Technol.

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The enrichment of geogenic phosphorus (P) in groundwater systems threatens environmental and public health worldwide. Two significant factors affecting geogenic P enrichment include organic matter (OM) and Fe (oxyhydr)oxide (FeOOH). However, due to variable reactivities of OM and FeOOH, variable strategies of their coupled influence controlling P enrichment in groundwater systems remain elusive. This research reveals that when the depositional environment is enriched in more labile aliphatic OM, its fermentation is coupled with the reductive dissolution of both amorphous and crystalline FeOOHs. When the depositional environment is enriched in more recalcitrant aromatic OM, it largely relies on crystalline FeOOH acting concurrently as electron acceptors while serving as “conduits” to help itself stimulate degradation and methanogenesis. The main source of geogenic P enriched by these two different coupled processes is different: the former is P-containing OM, which mainly contained unsaturated aliphatic compounds and highly unsaturated-low O compounds, and the latter is P associated with crystalline FeOOH. In addition, geological setting affects the deposition rate of sediments, which can alter OM degradation/preservation, and subsequently affects geochemical conditions of geogenic P occurrence. These findings provide new evidence and perspectives for understanding the hydro(bio)geochemical processes controlling geogenic P enrichment in alluvial-lacustrine aquifer systems.

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黏土沉积物压实过程中铁的迁移与转化机制：利用模拟实验进行的研究

Liu,

Ma,

Liu

et al. 2024

Hydrogeol J

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Effects of Fe oxides on organic carbon variation in the evolution of clayey aquitard and environmental significance

Cited by 22 publications

References 44 publications

Spatial Distribution and Factors Influencing the Various Forms of Iron in Alluvial–Lacustrine Clayey Aquitard

Spatial Distribution and Factors Influencing the Various Forms of Iron in Alluvial–Lacustrine Clayey Aquitard

Coupled Processes Involving Organic Matter and Fe Oxyhydroxides Control Geogenic Phosphorus Enrichment in Groundwater Systems: New Evidence from FT-ICR-MS and XANES

黏土沉积物压实过程中铁的迁移与转化机制：利用模拟实验进行的研究

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