Mechanisms of changing speciation and bioavailability of selenium in agricultural mollisols of northern cold regions

Zhang, Li; Ning, Junna; Liu, Guodong; Tong, Lei; Gan, Yiqun; Li, Chenglu; Yang, Wenpeng; Pi, Kunfu

doi:10.1016/j.scitotenv.2022.159897

Cited by 8 publications

(7 citation statements)

References 52 publications

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“…It is already known that Se bioavailability differs significantly between the dryland and paddy soils. , Land use change from conventional drylands to the current paddy wetlands can alter both structure (e.g., loss of stable aggregates) and physical–chemical–biological conditions of the Mollisol vadose zone. , For instance, the cultivated Mollisols suffer from soil acidity and redox shift that are companied by variations in the functional microbial community mediating redox zonation and nutrient release. , These factors affect directly the adsorption and redox transformation of Se species . In the context of global warming which impacts the cold regions disproportionately, these agricultural interventions make the Mollisols and Se in them prone to soil erosion, dehumification, and anthropogenic flooding. , Behind these changes is the increased potential of Se mobilization from the Mollisol layers, which are marginal or only moderately sufficient in Se. , Consequences for the bioavailability and sustainability of Se in the Mollisol agroecosystems, as well as the underlying processes and controlling mechanisms, however, remain to be elucidated.…”

Section: Introductionmentioning

confidence: 99%

“…3,10 Behind these changes is the increased potential of Se mobilization from the Mollisol layers, which are marginal or only moderately sufficient in Se. 11,12 Consequences for the bioavailability and sustainability of Se in the Mollisol agroecosystems, as well as the underlying processes and controlling mechanisms, however, remain to be elucidated. Hydro(bio)geochemical dynamics in the vadose zone form the basis of Se mobility and thus bioavailability through the food chain.…”

Section: Introductionmentioning

confidence: 99%

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Loss of Selenium from Mollisol Paddy Wetlands of Cold Regions: Insights from Flow-through Reactor Experiments and Process-Based Modeling

Cappellen

Tong

et al. 2023

Environ. Sci. Technol.

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Mollisols are critical agricultural resources for securing global food supply. Due to its health importance, selenium (Se) fate in the Mollisols attracts growing concerns. Land use change from conventional drylands to paddy wetlands impacts Se bioavailability in the vulnerable Mollisol agroecosystems. The underlying processes and mechanisms however remain elusive. Here, results of flow-through reactor experiments with paddy Mollisols from northern cold-region sites indicate that continuous flooding with surface water for 48 d induced redox zonation that facilitated the loss of Mollisol Se by up to 51%. Further process-based biogeochemical modeling suggests largest degradation rates of dissolved organic matter (DOM) in 30 cm deep Mollisols that contained the highest-level labile DOM and organicbound Se. Electron shunting from degradation of Se-bearing DOM coupled to reductive dissolution of Se-adsorbed Fe oxides accounts mainly for Se(IV) release into the pore water. Consequent changes in DOM molecular composition make the reservoir of organic-bound Se vulnerable to flooding-induced redox zonation and likely enhance Se loss through destruction of thiolated Se and emission of gaseous Se from the Mollisol layer. This study highlights a neglected scenario where the speciation-driven loss of bioavailable Se from the paddy wetlands can be a significant consequence in the cold-region Mollisol agroecosystems.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Loss of Selenium from Mollisol Paddy Wetlands of Cold Regions: Insights from Flow-through Reactor Experiments and Process-Based Modeling

Cappellen

Tong

et al. 2023

Environ. Sci. Technol.

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“…SeO − ), elemental selenium (Se) and methionine selenea (MetSe) [8] [9]. The chemical form of selenium influences its bioavailability and toxicity to living organisms (Wang et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Selenium can be adsorbed onto sediment particles or precipitated as insoluble compounds. The concentration of selenium in sediments can vary considerably depending on the sources of inputs, the physicochemical properties of the sediment and environmental conditions [8] [9] [10]. Selenium can be toxic to aquatic organisms at relatively low concentrations [11] [12].…”

Section: Introductionmentioning

confidence: 99%

Assessment of Selenium Contamination in Sediments of the Aby and Tendo Lagoons in C&#244;te d&#8217;Ivoire

Claon,

Kouassi,

N’Guettia

et al. 2024

IJG

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Selenium is a trace element that can have both beneficial and harmful effects on aquatic life. The Aby Lagoon is a coastal environment in Côte d'Ivoire that receives selenium inputs from various natural and anthropogenic sources. The aim of this study was to assess the levels of selenium in the sediments of the Aby Lagoon and its tributaries, the Tanoe River and the Tendo Lagoon, and to examine the spatial and seasonal variations of selenium concentrations. Sediment samples were collected from different sites and seasons, and selenium concentrations were measured by atomic fluorescence spectrometry. The results showed that the average concentration of selenium in the sediments of the Aby Lagoon was 0.82 mg/kg, indicating moderate contamination. The concentration of selenium varied between sites and seasons, with higher values in the channel of the Tendo Lagoon and during the dry season. The study highlighted the complexity of selenium dynamics in aquatic ecosystems, and the need to take into account seasonal and spatial variability as well as interactions between environmental factors. The study also suggested potential ecotoxicological risks for some sensitive organisms in certain areas of the lagoon. This study contributes to the knowledge of the dynamics of selenium in lagoon ecosystems and to the assessment of the environmental risks associated with its presence.

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“…Organic matters and iron minerals are known to influence Se mobility and biogeochemistry. − Sediments are critical components of Se geochemistry. Jones et al found that in the contaminated wetland they were studying, the sediment was storing 75% of the entering Se. , Oxic conditions at the sediment–water interface (SWI) can influence the Se sequestration.…”

Section: Introductionmentioning

confidence: 99%

Seasonal Contrasts in Dissolved Selenium Dynamics in Subarctic Thaw Lakes

Laberge-Carignan,

Pilote,

Larivière

et al. 2024

ACS Earth Space Chem.

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Thermokarst ponds (thaw lakes) are ubiquitous in northern landscapes. They are hotspots for the biogeochemical processing of elements, such as carbon (C), nitrogen (N), sulfur (S), iron (Fe) and manganese (Mn). In turn, those elementary cycles may control the mobility of selenium (Se), an essential micronutrient. To unravel these coupled biogeochemical cycles and identify processes controlling Se mobility, we studied four thermokarst ponds in a subarctic peatland valley influenced by permafrost thaw. The data set comprises of water column and sediment porewater concentration profiles collected during both summer and winter. Physicochemical parameters and dissolved concentrations of major elements, nutrients, and Se were measured and used to model fluxes at the sediment−water interface and to calculate Se speciation. The results suggest that the proximity of the pond from the permafrost structures influenced their biogeochemical dynamics. In the ponds close to permafrost, Se concentrations are 2-fold higher in winter compared to summer, accompanied by an increase in sediment fluxes from 13 to 149 pmol cm −2 yr −1 between summer and winter. The combination of comparatively older dissolved organic matter and of oxygenated conditions explain the seasonal variation in Se concentrations. In the ponds further from the permafrost, Se concentrations are higher, remain unchanged in the water column across seasons, and are linearly correlated with both DOC (R 2 = 0.64, p < 0.01, n = 50) and Fe (R 2 = 0.60) concentrations. Thermodynamic calculations show that Se(IV) dominates Se speciation in the porewater at all sites, while the water column reaches saturation with respect to elemental zerovalent Se, suggesting that precipitation of elemental Se could mediate dissolved Se concentrations. Collectively, our results point to the strong control that redox conditions exert on Se mobility, via DOC and Fe, and to the linkages between landscape features, pond physicochemistry, and Se dynamics.

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Mechanisms of changing speciation and bioavailability of selenium in agricultural mollisols of northern cold regions

Cited by 8 publications

References 52 publications

Loss of Selenium from Mollisol Paddy Wetlands of Cold Regions: Insights from Flow-through Reactor Experiments and Process-Based Modeling

Loss of Selenium from Mollisol Paddy Wetlands of Cold Regions: Insights from Flow-through Reactor Experiments and Process-Based Modeling

Assessment of Selenium Contamination in Sediments of the Aby and Tendo Lagoons in C&#244;te d&#8217;Ivoire

Seasonal Contrasts in Dissolved Selenium Dynamics in Subarctic Thaw Lakes

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Mechanisms of changing speciation and bioavailability of selenium in agricultural mollisols of northern cold regions

Cited by 8 publications

References 52 publications

Loss of Selenium from Mollisol Paddy Wetlands of Cold Regions: Insights from Flow-through Reactor Experiments and Process-Based Modeling

Loss of Selenium from Mollisol Paddy Wetlands of Cold Regions: Insights from Flow-through Reactor Experiments and Process-Based Modeling

Assessment of Selenium Contamination in Sediments of the Aby and Tendo Lagoons in C&amp;#244;te d&amp;#8217;Ivoire

Seasonal Contrasts in Dissolved Selenium Dynamics in Subarctic Thaw Lakes

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Assessment of Selenium Contamination in Sediments of the Aby and Tendo Lagoons in Côte d’Ivoire