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Kwak K, Varner TS, Nguyen W, Kulkarni HV, Buskirk R, Huang Y, Saeed A, Hosain A, Aitkenhead-Peterson J, Ahmed KM, Akhter SH, Cardenas MB, Datta S, Knappett PSK. Hotspots of Dissolved Arsenic Generated from Buried Silt Layers along Fluctuating Rivers. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58. [PMID: 39136409 PMCID: PMC11360370 DOI: 10.1021/acs.est.4c02330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 08/01/2024] [Accepted: 08/02/2024] [Indexed: 09/01/2024]
Abstract
Previous studies along the banks of the tidal Meghna River of the Ganges-Brahmaputra-Meghna Delta demonstrated the active sequestration of dissolved arsenic (As) on newly formed iron oxide minerals (Fe(III)-oxides) within riverbank sands. The sand with high solid-phase As (>500 mg/kg) was located within the intertidal zone where robust mixing occurs with oxygen-rich river water. Here we present new evidence that upwelling groundwater through a buried silt layer generates the dissolved products of reductive dissolution of Fe(III)-oxides, including As, while mobilization of DOC by upwelling groundwater prevents their reconstitution in the intertidal zone by lowering the redox state. A three end-member conservative mixing model demonstrated mixing between riverbank groundwater above the silt layer, upwelling groundwater through the silt layer, and river water. An electrochemical mass balance model confirmed that Fe(III)-oxides were the primary electron acceptor driving the oxidation of DOC sourced from sediment organic carbon in the silt. Thus, the presence of an intercalating silt layer in the riverbanks of tidal rivers can represent a biogeochemical hotspot of As release while preventing its retention in the hyporheic zone.
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Affiliation(s)
- Kyungwon Kwak
- Department
of Geology and Geophysics, Texas A&M
University, College
Station, Texas 77843, United States
| | - Thomas S. Varner
- Department
of Earth and Planetary Sciences, The University
of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - William Nguyen
- Department
of Earth and Planetary Sciences, The University
of Texas at Austin, Austin, Texas 78712, United States
| | - Harshad V. Kulkarni
- Department
of Earth and Planetary Sciences, The University
of Texas at San Antonio, San Antonio, Texas 78249, United States
- School
of Civil & Environmental Engineering, Indian Institute of Technology Mandi, Himachal Pradesh 175075, India
| | - Reid Buskirk
- Department
of Geology and Geophysics, Texas A&M
University, College
Station, Texas 77843, United States
| | - Yibin Huang
- Department
of Geology and Geophysics, Texas A&M
University, College
Station, Texas 77843, United States
| | - Abu Saeed
- Department
of Geology, University of Dhaka, Dhaka 1000, Bangladesh
| | - Alamgir Hosain
- Department
of Coastal Studies and Disaster Management, University of Barishal, Barishal 8200, Bangladesh
| | | | - Kazi M. Ahmed
- Department
of Geology, University of Dhaka, Dhaka 1000, Bangladesh
| | | | - M. Bayani Cardenas
- Department
of Earth and Planetary Sciences, The University
of Texas at Austin, Austin, Texas 78712, United States
| | - Saugata Datta
- Department
of Earth and Planetary Sciences, The University
of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Peter S. K. Knappett
- Department
of Geology and Geophysics, Texas A&M
University, College
Station, Texas 77843, United States
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Duan L, Song J, Zhang Y, Yin M, Yuan H, Li X. Unraveling seasonal shifts in microbial and geochemical mediated arsenic mobilization at the estuarine sediment-water interface under redox changes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:168939. [PMID: 38029978 DOI: 10.1016/j.scitotenv.2023.168939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/19/2023] [Accepted: 11/25/2023] [Indexed: 12/01/2023]
Abstract
The mobilization of arsenic (As) at the sediment-water interface (SWI) is crucial for determining the accumulation of dissolved As to potentially toxic levels. However, the specific impacts of redox processes involving iron (Fe) and sulfur (S), as well as microbial activities occurring in sediments, on As mobilization at the marine SWI remain poorly understood. In this study, we investigated As mobilization at the SWI in the Changjiang Estuary during three different seasons with different benthic redox conditions. The preferential reduction of arsenate (As(V)) to arsenite (As(III)) and subsequent re-adsorption onto newly formed crystalline Fe oxides restricted As release in the As(V) reduction layer. Enhanced Fe(III) reduction in the Fe(III) reduction layer contributed to As release, while the presence of low As-high Fe-high SO42- levels resulted in As removal through adsorption onto pyrite in the sulfate reduction layer. Analysis of functional genes indicated that As(V) in sediments was released into porewater through the reductive dissolution of As(V)-bearing Fe(III) oxides by Geobacter species, followed by microbial reduction of the liberated As(V) to As(III) by microbes carrying the arrA gene. The dominant pathway governing As mobilization at the SWI in the Changjiang Estuary shifted from microbial reduction control during the hypoxic summer to Fe redox control during the aerobic autumn and winter. These findings provide valuable insights into the complex mechanisms driving As mobilization and highlight the importance of considering seasonal variations in understanding As dynamics at the marine SWI.
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Affiliation(s)
- Liqin Duan
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Sciences, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China.
| | - Jinming Song
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Sciences, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China
| | - Yuting Zhang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Meiling Yin
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Huamao Yuan
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Sciences, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China
| | - Xuegang Li
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Sciences, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China
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3
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Ojeda AS, Herron C, Olshansky Y, Malina N. Arsenic-dissolved organic matter complexation in water soluble extracts from lignite. CHEMOSPHERE 2023; 342:140036. [PMID: 37714477 DOI: 10.1016/j.chemosphere.2023.140036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/17/2023]
Abstract
Arsenic in groundwater is a global threat to public health. Recently, As mobility has been tied to the concentration and chemical characteristics of dissolved organic matter (DOM) through formation of As-DOM complexes. To date, there has been a wide range of DOM types studied to understand As-DOM interactions, but most of these have focused on surface water derived materials and not groundwater DOM. We address this gap in knowledge by simulating groundwater DOM using water extractable organic matter (WEOM) from two lignite deposits and treating the extracts with increasing concentrations of As. As-DOM complexes were measured using size-exclusion chromatography coupled to multiple detectors including an inductively coupled plasma mass spectrometer (ICPMS) for As detection as well as fluorescence and variable wave detectors for organic matter detection. First, we found two different size fractions of As-DOM, one of ∼1 kDa and another of ∼15 kDa, depending on the DOM types. The smaller As-DOM complex (∼1 kDa) was approximately 10 times more abundant than the larger complex (∼15 kDa). Second, we found that the lignite derived DOMs showed higher conditional distribution coefficients than did the surface water reference material (Suwanee River Natural Organic Matter, SRNOM). Finally, the data showed good fit (R2 > 0.92) to one-site ligand binding models, and the lignite derived DOMs showed higher maximum sorbate concentrations (Bmax) compared to SRNOM. Together, this study shows that As-DOM complexation is an important control on As speciation, even in groundwater systems.
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Affiliation(s)
- Ann S Ojeda
- Department of Geosciences, Auburn University, USA.
| | | | - Yaniv Olshansky
- Department of Crop, Soil, and Environmental Sciences, Auburn University, USA
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Gao Z, Guo H, Chen D, Yu C, He C, Shi Q, Qiao W, Kersten M. Transformation of dissolved organic matter and related arsenic mobility at a surface water-groundwater interface in the Hetao Basin, China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 334:122202. [PMID: 37453683 DOI: 10.1016/j.envpol.2023.122202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/26/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023]
Abstract
Porewater arsenic mobility above the groundwater table has been recognized as a potential cause of arsenic-rich groundwater, but the processing pathways of dissolved organic matter (DOM) in that hyporheic zone and their effect on porewater arsenic release remain poorly understood. To address these issues, two porewater profiles were sampled in a surface water-groundwater interaction zone from the Hetao Basin, China, to monitor the porewater geochemistry and DOM molecular characteristics. The results show that the porewater arsenic, Fe(II), and DOC concentrations were all significantly higher than those of the intruding pond water, and were located above the conservative mixing model lines. This indicates a net release of these solutes from the sediment. By comparing the porewater with pond water DOM, we found that the carboxyl-rich alicyclic molecules (CRAM) were selectively preserved, carbohydrates and aliphatics/proteins were preferentially consumed, and low O/C-ratio compounds with high bioproduction index (I_bioprod) and terrestrial index (I_terr) were produced. The transformation of CHO to CHOS compounds also represented a pathway of recalcitrant DOM production. The produced recalcitrant organic compounds mostly contributed to the elevated porewater DOC concentrations, but their contribution decreased along the filtration path. The consumption of labile DOM compounds would be responsible for Fe(III) hydroxide reduction and arsenic release. The generated recalcitrant DOM may also be a driver of porewater arsenic mobility by acting as electron shuttles. This study highlights the importance of the hyporheic zone in shaping shallow groundwater DOM composition and the potential contribution to arsenic enrichment.
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Affiliation(s)
- Zhipeng Gao
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, 100083, PR China; MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, and School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, PR China
| | - Huaming Guo
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, 100083, PR China; MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, and School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, PR China.
| | - Dou Chen
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, and School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, PR China
| | - Chen Yu
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, and School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, PR China
| | - Chen He
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing, 102249, PR China
| | - Quan Shi
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing, 102249, PR China
| | - Wen Qiao
- China Institute of Geo-Environment Monitoring, China Geological Survey, Beijing, 100081, PR China
| | - Michael Kersten
- Environmental Geochemistry Group, Institute of Geosciences, Johannes Gutenberg-University, Mainz, 55099, Germany
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5
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Duan L, Song J, Zhang Y, Yuan H, Li X, Sun L. Role of marine algal blooms in the release of arsenic at the sediment-seawater interface: Evidence from microcosm experiments. WATER RESEARCH 2023; 244:120508. [PMID: 37633211 DOI: 10.1016/j.watres.2023.120508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 08/12/2023] [Accepted: 08/18/2023] [Indexed: 08/28/2023]
Abstract
Algal blooms can aggravate arsenic (As) release from sediments and thus pose a pollution risk in the marine environment. However, the driving mechanism of algal blooms on sedimentary As cycling remains unclear. This study undertakes the first comprehensive examination of As release mechanisms under algal bloom conditions based on the evidence provided by temporal and depth profile changes of As species in the overlying water column, porewater and sediment, as well as As-related functional genes over the course of a 30-day incubation experiment using algal addition. The higher rate of increase of dissolved total As (dTAs) concentrations in a high biomass algal group (HAG) than an experimental control group (CG) suggested that algal degradation promoted the release of sedimentary As. The solid phase in all experimental groups remained rich in As(V), while in porewater As(III) and As(V) were the dominant As species during the initial rapid and subsequent slow degradation phases of organic matter, respectively, indicating that microbial reduction of As(V) and Fe(III) controlled the release of As during these two periods. A pronounced increase in arrA gene copies, and not a corresponding increase in the Geobacter copies, in HAG relative to CG supported the notion that algal blooms promoted microbial As(V) reduction. Additionally, the lower concentration of dissolved As(III) and cumulative dTAs flux in the sterilized-HAG treatment than in the sterilized-CG one further suggested that geochemically-mediated processes were not the main pathways of As release. Finally, it is estimated that summer algal blooms in the Changjiang Estuary can cause the release of 1440 kg of sedimentary As into the overlying water.
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Affiliation(s)
- Liqin Duan
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Sciences, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China.
| | - Jinming Song
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Sciences, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China
| | - Yuting Zhang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Huamao Yuan
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Sciences, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China
| | - Xuegang Li
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Laboratory for Marine Ecology and Environmental Sciences, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China
| | - Lingling Sun
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Public Technology Service Center, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China
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