Vertical redox zones of Fe–S–As coupled mineralogy in the sediments of Hetao Basin – Constraints for groundwater As contamination

Wang, H. Y.; Göttlicher, Jörg; Byrne, James M.; Guo, Huaming; Benning, Liane G.; Norra, Stefan

doi:10.1016/j.jhazmat.2020.124924

Cited by 16 publications

(9 citation statements)

References 64 publications

(92 reference statements)

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“…SEM-EDS images showed the presence of Fe–S containing mineral particles (∼1 μm in diameter) (Figure S3), consistent with the fact that the monosulfide fraction was generally the highest reduced S fraction (most around 50%) in the study area . The occurrence of secondary pyrite or even greigite in the study area has also been recently confirmed by Fe–S–As K-edge XANES data. , Taken together, these suggest that the Fe–S containing mineral particles were mainly secondary pyrite, which was widely found in high As aquifer sediments. , The formation of pyrite particles could immobilize aqueous As, while the oxidation of As-containing secondary pyrite particles would release the bond As. , The high sulfate extract. (356 ± 76 mg/kg), Fe(II) sed /TFe sed (57.4 ± 1.9%), and ammonium extract.…”

Section: Resultssupporting

confidence: 82%

“…7 The occurrence of secondary pyrite or even greigite in the study area has also been recently confirmed by Fe−S−As K-edge XANES data. 76,77 Taken together, these suggest that the Fe−S containing mineral particles were mainly secondary pyrite, which was widely found in high As aquifer sediments. 78,79 The formation of pyrite particles could immobilize aqueous As, 68 while the oxidation of As-containing secondary pyrite particles would release the bond As.…”

Section: ■ Results and Discussionmentioning

confidence: 83%

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Understanding Microbial Arsenic-Mobilization in Multiple Aquifers: Insight from DNA and RNA Analyses

Xiu

Lloyd

et al. 2021

Environ. Sci. Technol.

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Biogeochemical processes critically control the groundwater arsenic (As) enrichment; however, the key active As-mobilizing biogeochemical processes and associated microbes in high dissolved As and sulfate aquifers are poorly understood. To address this issue, the groundwater-sediment geochemistry, total and active microbial communities, and their potential functions in the groundwater-sediment microbiota from the western Hetao basin were determined using 16S rRNA gene (rDNA) and associated 16S rRNA (rRNA) sequencing. The relative abundances of either sediment or groundwater total and active microbial communities were positively correlated. Interestingly, groundwater active microbial communities were mainly associated with ammonium and sulfide, while sediment active communities were highly related to water-extractable nitrate. Both sediment-sourced and groundwater-sourced active microorganisms (rRNA/rDNA ratios > 1) noted Fe(III)-reducers (induced by ammonium oxidation) and As(V)-reducers, emphasizing the As mobilization via Fe(III) and/or As(V) reduction. Moreover, active cryptic sulfur cycling between groundwater and sediments was implicated in affecting As mobilization. Sediment-sourced active microorganisms were potentially involved in anaerobic pyrite oxidation (driven by denitrification), while groundwater-sourced organisms were associated with sulfur disproportionation and sulfate reduction. This study provides an extended whole-picture concept model of active As−N−S−Fe biogeochemical processes affecting As mobilization in high dissolved As and sulfate aquifers.

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Section: Resultssupporting

confidence: 82%

Section: ■ Results and Discussionmentioning

confidence: 83%

Understanding Microbial Arsenic-Mobilization in Multiple Aquifers: Insight from DNA and RNA Analyses

Xiu

Lloyd

et al. 2021

Environ. Sci. Technol.

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“…There is a tension in the literature about the affinity of AsO 4 3– and PO 4 3– for adsorption on iron oxyhydroxides (e.g., Gt). While some studies reported higher adsorption of AsO 4 , − , some other studies showed that PO 4 − ,,…”

Section: Results and Discussionmentioning

confidence: 95%

“…Antelo et al reported that PO 4 3– is more sensitive to changes in pH and ionic strength. They showed that PO 4 3– adsorption increases in acidic pH at different ionic strengths and decreases at basic pH and low ionic strengths, compared to AsO 4 . − Therefore, the AsO 4 3– and PO 4 3– adsorption on iron oxy-hydroxides depends on the system chemistry and may not be identical under different chemical conditions . In addition, Langmuir proposed that smaller ions with higher charges, that is, with a higher ionic potential (IP = Z/r), show a higher affinity for forming a strong covalent bond on the surface of solids.…”

Section: Results and Discussionmentioning

confidence: 99%

Effects of Oxyanion Surface Loading on the Rate and Pathway of Ferrihydrite Transformation

Namayandeh,

Borkiewicz,

Bompoti

et al. 2023

ACS Earth Space Chem.

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In natural environments, ferrihydrite (Fh) reacts readily with the contaminant and nutrient oxyanions through surface complexation. While previous experiments showed that the transformation of Fh to Gt and Hm under oxic conditions at 70 °C is controlled by the type and strength of oxyanion surface complexes, the impact of surface loading on this process is only partly understood. Synchrotron scattering methods and chemical analysis were used to develop a kinetic model that describes the impact of oxyanion surface loading on the rate and pathway of Fh transformation by using arsenate (AsO4 3–) and phosphate (PO4 3–). Kinetic modeling showed that AsO4 3– and PO4 3– adsorption decreased the rate of transformation and favored Hm formation over Gt. Higher surface loadings increasingly inhibited Fh transformation with a greater effect for PO4 3– compared with AsO4 3–. This information has implications for understanding the impacts of oxyanions on the transformation of natural Fe to Gt and Hm in environmental systems.

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“…The current recommended limit of arsenic in drinking-water is 10 μg/L [5]. As rich groundwater (As >10 ug/L) is widely observed in many parts of the world such as Australia [6], Bangladesh [4], China [7], India [8], USA [9], South Korea [10] and Vietnam [11]. Flanagan et al [4] estimated that about 20 million and 45 million people in Bangladesh were exposed to As concentration greater than 50 g/L and 10 g/L respectively and approximately 24,000 deaths annually in the country due to the consumption of As rich groundwater.…”

Section: Introductionmentioning

confidence: 99%

Health risk assessment of arsenic in drinking groundwater: A case study in a central high land area of Vietnam

Hoang

Vinh

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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Arsenic contaminated groundwaters is a global environmental issue which cause serious problems for human health risks. 188 groundwater samples were collected in private wells of Lam Dong Province, a central highland area, Vietnam to investigate the health risks to the local people by using arsenic contaminated groundwater for drinking purpose. The result showed that the arsenic concentration is average of 14 μg/L and maximum of 500 μg/L. About 12% out of the total groundwater samples have arsenic concentration exceeded that value of 10 μg/L recommended for drinking water by World Health Organization (WHO, 2019). The health risk assessment showed that hazard quotient (HQ) value for adults was up to 60.6 with an average of 1.7 and about 14% of total samples show the HQ values greater than 1. The HQ value for children is average of 4.7 (maximum of 166.7) and about 23% of total groundwater samples show HQ > 1 for children. Cancer risk (CR) values were up to 27x10-4 (average of 8x10-4) for adults and 75x10-4 (average of 21x10-4) for children. About 26% and 29% of out of the total samples show CR value for adult and children greater than the CR (1×10-4) proposed by the USEPA. The result also indicated that the consumption of arsenic contaminated groundwater may seriously damage the human health. Therefore, groundwater in the area needs to be treated for arsenic removal before drinking to minimize the adverse effect on local communities’ health.

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Vertical redox zones of Fe–S–As coupled mineralogy in the sediments of Hetao Basin – Constraints for groundwater As contamination

Cited by 16 publications

References 64 publications

Understanding Microbial Arsenic-Mobilization in Multiple Aquifers: Insight from DNA and RNA Analyses

Understanding Microbial Arsenic-Mobilization in Multiple Aquifers: Insight from DNA and RNA Analyses

Effects of Oxyanion Surface Loading on the Rate and Pathway of Ferrihydrite Transformation

Health risk assessment of arsenic in drinking groundwater: A case study in a central high land area of Vietnam

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