Unraveling the impact of iron oxides-organic matter complexes on iodine mobilization in alluvial-lacustrine aquifers from central Yangtze River Basin

Xue, Jiangkai; Deng, Yamin; Luo, Yipeng; Du, Yao; Yang, Yijun; Cheng, Ying; Xie, Xianjun; Gan, Yiqun; Wang, Yanxin

doi:10.1016/j.scitotenv.2021.151930

Cited by 16 publications

(16 citation statements)

References 71 publications

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“…In aquifers, iodate and organic iodine are primarily bound to organic matter-rich iron minerals and thus microbially mediated reductive dissolution of iron minerals is believed to liberate the adsorbed iodine into groundwater. , Previous studies showed that SRB, such as Desulfovibrio vulgaris, Desulfovibrio putealis, and Desulfovibrio desulfuricans strain G-20, can not only biotically reduce iron oxides and clay minerals, but also perform chemical iron reduction through biogenic sulfide. − Therefore, bacterial sulfate reduction in the deep confined high-iodine aquifers of the NCP may facilitate the reductive dissolution of iodine-bearing iron minerals and release adsorbed iodine into groundwater. This indirect iodine mobilization by bacterial sulfate reduction is similar to biogenic sulfide-driven arsenic mobilization in groundwater. , In addition, SRB could act directly on iodate reduction through sulfide-driven abiotic or enzymatic reactions.…”

Section: Discussionmentioning

confidence: 99%

“…Thermodynamically, iodide is the dominant species in reducing and weakly alkaline geogenic high-iodine groundwater, while iodate and organic iodine are mainly bound to aquifer sediments. , Given the low affinity of iodide to solid matrices, microbially mediated reduction of iodate is considered to be the main mechanism for iodide generation and enrichment in groundwater. − To date, dissimilatory iodate-reducing bacteria and iron-reducing bacteria have been found to reduce iodate to iodide. For instance, dissimilatory iodate-reducing Denitromonas sp.…”

Section: Introductionmentioning

confidence: 99%

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Bacterial Sulfate Reduction Facilitates Iodine Mobilization in the Deep Confined Aquifer of the North China Plain

Jiang,

Qian,

Cui

et al. 2023

Environ. Sci. Technol.

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Bacterial sulfate reduction plays a crucial role in the mobilization of toxic substances in aquifers. However, the role of bacterial sulfate reduction on iodine mobilization in geogenic high-iodine groundwater systems has been unexplored. In this study, the enrichment of groundwater δ34SSO4 (15.56 to 69.31‰) and its significantly positive correlation with iodide and total iodine concentrations in deep groundwater samples of the North China Plain suggested that bacterial sulfate reduction participates in the mobilization of groundwater iodine. Similar significantly positive correlations were further observed between the concentrations of iodide and total iodine and the relative abundance of the dsrB gene by qPCR, as well as the composition and abundance of sulfate-reducing bacteria (SRB) predicted from 16S rRNA gene high-throughput sequencing data. Subsequent batch culture experiments by the SRB Desulfovibrio sp. B304 demonstrated that SRB could facilitate iodine mobilization through the enzyme-driven biotic and sulfide-driven abiotic reduction of iodate to iodide. In addition, the dehalogenation of organoiodine compounds by SRB and the reductive dissolution of iodine-bearing iron minerals by biogenic sulfide could liberate bound or adsorbed iodine into groundwater. The role of bacterial sulfate reduction in iodine mobilization revealed in this study provides new insights into our understanding of iodide enrichment in iodine-rich aquifers worldwide.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bacterial Sulfate Reduction Facilitates Iodine Mobilization in the Deep Confined Aquifer of the North China Plain

Jiang,

Qian,

Cui

et al. 2023

Environ. Sci. Technol.

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“…In addition to microbial iodate reduction, soluble ferrous iron, sulfide, and iron monosulfide were shown to reduce iodate to iodide abiotically . Based on the role of these strains and hydrogeochemical analysis, the reductions of iron and sulfate were proposed to play important roles in iodide mobilization in groundwater. ,,, However, this speculation has not been substantiated by the field observations. The functional roles of iodate-reducing, nitrate-reducing, iron-reducing, and sulfate-reducing microorganisms in iodine mobilization in aquifers are still unclear.…”

Section: Introductionmentioning

confidence: 99%

Microbial Contributions to Iodide Enrichment in Deep Groundwater in the North China Plain

Jiang

Huang

Jiang

et al. 2023

Environ. Sci. Technol.

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Microorganisms play crucial roles in the global iodine cycling through iodine oxidation, reduction, volatilization, and deiodination. In contrast to iodate formation in radionuclidecontaminated groundwater by the iodine-oxidizing bacteria, microbial contribution to the formation of high level of iodide in geogenic high iodine groundwater is poorly understood. In this study, our results of comparative metagenomic analyses of deep groundwater with typical high iodide concentrations in the North China Plain revealed the existence of putative dissimilatory iodate-reducing idrABP1P2 gene clusters in groundwater. Heterologous expression and characterization of an identified idrABP1P2 gene cluster confirmed its functional role in iodate reduction. Thus, microbial dissimilatory iodate reduction could contribute to iodide formation in geogenic high iodine groundwater. In addition, the identified iron-reducing, sulfur-reducing, sulfur-oxidizing, and dehalogenating bacteria in the groundwater could contribute to the release and production of iodide through the reductive dissolution of iron minerals, abiotic iodate reduction of derived ferrous iron and sulfide, and dehalogenation of organic iodine, respectively. These microbially mediated iodate reduction and organic iodine dehalogenation processes may also result in the transformation among iodine species and iodide enrichment in other geogenic iodine-rich groundwater systems worldwide.

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“…Many studies have confirmed that newly-formed amorphous iron (hydro) oxides preferentially bind phenolics and aromatic organic matter [ 11 , 13 , 30 , 31 , 32 ]. In addition, high molecular weight (MW > 500 Da) organic compounds and highly unsaturated or oxygen-rich organic matter (including polycyclic aromatic hydrocarbons, polyphenols, and carboxylic acid) have a higher affinity for iron (hydro) oxides [ 33 ].…”

Section: Introductionmentioning

confidence: 99%

“…The mechanism is that enzymatic polymerization transforms small molecular organic matter into larger molecule DOM with stronger iron affinity and then combines with iron ions to form Fe-OM through coprecipitation [ 34 , 35 ]. In general, organic matter with higher MW diffuse more slowly and have a stronger affinity for binding sites, while more minor MW organic matter tends to be more difficult to immobilize due to its weaker affinity [ 22 , 32 , 36 , 37 ]. At present, it is unclear how laccase-mediated Fe-OM affects the environmental behavior of metal(loid)s.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Adsorption of Cd on Iron–Organic Associations Formed by Laccase-Mediated Modification: Implications for the Immobilization of Cadmium in Paddy Soil

Yang

Huang

Xiang

et al. 2022

IJERPH

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The objectives of this study were to evaluate the cadmium adsorption capacity of iron–organic associations (Fe-OM) formed by laccase-mediated modification and assess the effect of Fe-OM on the immobilization of cadmium in paddy soil. Leaf organic matter (OM) was extracted from Changshan grapefruit leaves, and then dissolved organic matter (Lac-OM) and precipitated organic matter (Lac-P) were obtained by laccase catalytic modification. Different Fe-OM associations were obtained by co-precipitation of Fe with OM, Lac-OM, and Lac-P, respectively, and the adsorption kinetics, adsorption edge, and isothermal adsorption experiments of Cd on Fe-OM were carried out. Based on the in situ generation of Fe-OM, passivation experiments on Cd-contaminated soils with a high geological background were carried out. All types of Fe-OM have a better Cd adsorption capacity than ferrihydrite (FH). The theoretical maximum adsorption capacity of the OM-FH, Lac-OM-FH, and Lac-P-FH were 2.2, 2.53, and 2.98 times higher than that of FH, respectively. The adsorption of Cd on Fe-OM is mainly chemisorption, and the -OH moieties on the Fe-OM surface form an inner-sphere complex with the Cd ions. Lac-OM-FH showed a higher Cd adsorption capacity than OM-FH, which is related to the formation of more oxygen-containing groups in the organic matter modified by laccase. The immobilization effect of Lac-OM-FH on active Cd in soil was also higher than that of OM-FH. The Lac-OM-FH formed by laccase-mediated modification has better Cd adsorption performance, which can effectively inactivate the activity of Cd in paddy soil.

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Unraveling the impact of iron oxides-organic matter complexes on iodine mobilization in alluvial-lacustrine aquifers from central Yangtze River Basin

Cited by 16 publications

References 71 publications

Bacterial Sulfate Reduction Facilitates Iodine Mobilization in the Deep Confined Aquifer of the North China Plain

Bacterial Sulfate Reduction Facilitates Iodine Mobilization in the Deep Confined Aquifer of the North China Plain

Microbial Contributions to Iodide Enrichment in Deep Groundwater in the North China Plain

Enhanced Adsorption of Cd on Iron–Organic Associations Formed by Laccase-Mediated Modification: Implications for the Immobilization of Cadmium in Paddy Soil

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