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Ding Y, Sun W, Liu S, Xie J, Tang D, Zhou X, Zhou L, Li Z, Song J, Li Z, Xu H, Tang P, Liu K, Li W, Chen D. Low oxygen levels with high redox heterogeneity in the late Ediacaran shallow ocean: Constraints from I/(Ca + Mg) and Ce/Ce* of the Dengying Formation, South China. Geobiology 2022; 20:790-809. [PMID: 36250398 DOI: 10.1111/gbi.12520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 03/23/2022] [Accepted: 07/22/2022] [Indexed: 06/16/2023]
Abstract
Most previous studies focused on the redox state of the deep water, leading to an incomplete understanding of the spatiotemporal evolution of the redox-stratified ocean during the Ediacaran-Cambrian transition. In order to decode the redox condition of shallow marine environments during the late Ediacaran, this study presents I/(Ca + Mg), carbon and oxygen isotope, major, trace, and rare earth element data of subtidal to peritidal dolomite from the Dengying Formation at Yangba, South China. In combination with the reported radiometric and biostratigraphic data, the Dengying Formation and coeval successions worldwide are subdivided into a positive δ13 C excursion (up to ~6‰) in the lower part (~551-547 Ma) and a stable δ13 C plateau (generally between 0‰ and 3‰) in the middle-upper part (~547-541 Ma). The overall low I/(Ca + Mg) ratios (<0.5 μmol/mol) and slightly negative to no Ce anomalies (0.80 < [Ce/Ce*]SN < 1.25), point to low-oxygen levels in shallow marine environments at Yangba. Moreover, four pulsed negative excursions in (Ce/Ce*)SN (between 0.62 and 0.8) and the associated two positive excursions in I/(Ca + Mg) ratios (up to 2.02 μmol/mol) are observed, indicative of weak oxygenations in the shallow marine environments. The comparison with other upper Ediacaran shallow water successions worldwide reveals that the (Ce/Ce*)SN and I/(Ca + Mg) values generally fall in the Precambrian range but their temporal trends differ among these successions (e.g., Ce anomaly profiles significantly different between Yangba and the Yangtze Gorge sections), which point to low oxygen levels with high redox heterogeneity in the surface ocean. This is consistent with the widespread anoxia as revealed by low δ238 U values reported by previous studies. Thus, the atmospheric oxygen concentrations during the late Ediacaran are estimated to be very low, similar to the case during the most Mesoproterozoic to early Neoproterozoic period.
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Affiliation(s)
- Yi Ding
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, China
- Key Laboratory of Deep-Time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources, Chengdu University of Technology, Chengdu, China
| | - Wei Sun
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, China
| | - Shugen Liu
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, China
- Xihua University, Chengdu, China
| | - Jirong Xie
- Exploration and Development Research Institute, PetroChina Southwest Oil & Gas Field Company, Chengdu, China
| | - Dongjie Tang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, China
| | - Xiqiang Zhou
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- Innovation Academy for Earth Science, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Limin Zhou
- National Research Center of Geoanalysis, Beijing, China
| | - Zhiwu Li
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, China
| | - Jinmin Song
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, China
| | - Zeqi Li
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, China
| | - Hongyuan Xu
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, China
| | - Pan Tang
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Kang Liu
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Wenjun Li
- Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - Daizhao Chen
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- Innovation Academy for Earth Science, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
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Yan PF, Dong S, Manz KE, Liu C, Woodcock MJ, Mezzari MP, Abriola LM, Pennell KD, Cápiro NL. Biotransformation of 8:2 Fluorotelomer Alcohol in Soil from Aqueous Film-Forming Foams (AFFFs)-Impacted Sites under Nitrate-, Sulfate-, and Iron-Reducing Conditions. Environ Sci Technol 2022; 56:13728-13739. [PMID: 36127292 DOI: 10.1021/acs.est.2c03669] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The environmental fate of per- and polyfluoroalkyl substances (PFAS) in aqueous film-forming foams (AFFFs) remains largely unknown, especially under the conditions representative of natural subsurface systems. In this study, the biotransformation of 8:2 fluorotelomer alcohol (8:2 FTOH), a component of new-generation AFFF formulations and a byproduct in fluorotelomer-based AFFFs, was investigated under nitrate-, iron-, and sulfate-reducing conditions in microcosms prepared with AFFF-impacted soils. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high-resolution mass spectrometry (HRMS) were employed to identify biotransformation products. The biotransformation was much slower under sulfate- and iron-reducing conditions with >60 mol % of initial 8:2 FTOH remaining after ∼400 days compared to a half-life ranging from 12.5 to 36.5 days under nitrate-reducing conditions. Transformation products 8:2 fluorotelomer saturated and unsaturated carboxylic acids (8:2 FTCA and 8:2 FTUA) were detected under all redox conditions, while 7:2 secondary fluorotelomer alcohol (7:2 sFTOH) and perfluorooctanoic acid (PFOA) were only observed as transformation products under nitrate-reducing conditions. In addition, 1H-perfluoroheptane (F(CF2)6CF2H) and 3-F-7:3 acid (F(CF2)7CFHCH2COOH) were identified for the first time during 8:2 FTOH biotransformation. Comprehensive biotransformation pathways for 8:2 FTOH are presented, which highlight the importance of accounting for redox condition and the related microbial community in the assessment of PFAS transformations in natural environments.
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Affiliation(s)
- Peng-Fei Yan
- Department of Civil and Environmental Engineering, Auburn University, Auburn, Alabama 36849, United States
| | - Sheng Dong
- Department of Civil and Environmental Engineering, Auburn University, Auburn, Alabama 36849, United States
| | - Katherine E Manz
- School of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - Chen Liu
- School of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - Matthew J Woodcock
- School of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - Melissa P Mezzari
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030-3411, United States
| | - Linda M Abriola
- School of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - Kurt D Pennell
- School of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - Natalie L Cápiro
- Department of Civil and Environmental Engineering, Auburn University, Auburn, Alabama 36849, United States
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Touch N, Hibino T, Nakashita S, Nakamoto K. Variation in properties of the sediment following electrokinetic treatments. Environ Technol 2017; 38:277-284. [PMID: 27218205 DOI: 10.1080/09593330.2016.1190408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 05/11/2016] [Indexed: 06/05/2023]
Abstract
Many studies have reported variation in properties of the sediment within electrokinetic treatments (EKTs). However, we aim to reveal the variation in properties of the sediment following EKTs through laboratory experiments. We collected sewage-derived sediment from a littoral region, and passed it through a 2-mm sieve. We used a potentiostat to cause electrical current in EKT. We measured the sediment properties such as pH, redox potential (ORP), and hydrogen sulphide (H2S) concentration at the end of EKT and at 30 days following EKT. Results showed decreases in pH, increases in ORP, and decreases in H2S concentration at the end of EKT. Compared with the sediment without EKT, the decrease in ORP for the sediment within EKT was higher at 30 days following EKT. These suggest that anaerobic digestion of organic compounds occurs in the sediment following EKT, of which the oxidants produced by EKT serve as electron acceptors and organic compounds serve as electron donors. Furthermore, we found that EKT can remove H2S from the sediment and reduce H2S production in the sediment within EKT when compared to the case without EKT. These ensure that EKT can be used to remove H2S and control H2S production in the sediment.
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Affiliation(s)
- Narong Touch
- a Civil and Environmental Engineering , Hiroshima University , Higashihiroshima City , Japan
| | - Tadashi Hibino
- a Civil and Environmental Engineering , Hiroshima University , Higashihiroshima City , Japan
| | - Shinya Nakashita
- a Civil and Environmental Engineering , Hiroshima University , Higashihiroshima City , Japan
| | - Kenji Nakamoto
- a Civil and Environmental Engineering , Hiroshima University , Higashihiroshima City , Japan
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