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Zhao S, Wang J, Feng S, Xiao Z, Chen C. Effects of ecohydrological interfaces on migrations and transformations of pollutants: A critical review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 804:150140. [PMID: 34509841 DOI: 10.1016/j.scitotenv.2021.150140] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/24/2021] [Accepted: 08/31/2021] [Indexed: 06/13/2023]
Abstract
With the rapid development of society, the soil and water environments in many countries are suffering from severe pollution. Pollutants in different phases will eventually gather into the soil and water environments, and a series of migrations and transformations will take place at ecohydrological interfaces with water flow. However, it is still not clear how ecohydrological interfaces affect the migration and the transformation of pollutants. Therefore, this paper summarizes the physical, ecological, and biogeochemical characteristics of ecohydrological interfaces on the basis of introducing the development history of ecohydrology and the concept of ecohydrological interfaces. The effects of ecohydrological interfaces on the migration and transformation of heavy metals, organic pollutants, and carbon‑nitrogen‑phosphorus (C-N-P) pollutants are emphasized. Lastly, the prospects of applying ecohydrological interfaces for the removal of pollutants from the soil and water environment are put forward, including strengthening the ability to monitor and simulate ecohydrological systems at micro and macro scales, enhancing interdisciplinary research, and identifying main influencing factors that can provide theoretical basis and technical support.
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Affiliation(s)
- Shan Zhao
- College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai 201306, China; College of Civil Engineering, Tongji University, Shanghai 200092, China
| | - Jianhua Wang
- College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai 201306, China
| | - Shijin Feng
- College of Civil Engineering, Tongji University, Shanghai 200092, China.
| | - Zailun Xiao
- College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai 201306, China
| | - Chunyan Chen
- College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai 201306, China
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2
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Zhang Z, Furman A. Soil redox dynamics under dynamic hydrologic regimes - A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 763:143026. [PMID: 33143917 DOI: 10.1016/j.scitotenv.2020.143026] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/04/2020] [Accepted: 10/08/2020] [Indexed: 06/11/2023]
Abstract
Electron transfer (redox) reactions, mediated by soil microbiota, modulate elemental cycling and, in part, establish the redox poise of soil systems. Understanding soil redox processes significantly improves our ability to characterize coupled biogeochemical cycling in soils and aids in soil health management. Redox-sensitive species exhibit different reactivity, mobility, and toxicity subjected to their redox state. Thus, it is crucial to quantify the redox potential (Eh) in soils and to characterize the dominant redox couples therein. Several, often coupled, external drivers, can influence Eh. Among these factors, soil hydrology dominates. It controls soil physical properties that in turn further regulates Eh. Soil spatial heterogeneity and temporally dynamic hydrologic regimes yield complex distributions of Eh. Soil redox processes have been studied under various environmental conditions, including relatively static and dynamic hydrologic regimes. Our focus here is on dynamic, variably water-saturated environments. Herein, we review previous studies on soil redox dynamics, with a specific focus on dynamic hydrologic regimes, provide recommendations on knowledge gaps, and targeted future research needs and directions. We review (1) the role of soil redox conditions on the soil chemical-species cycling of organic carbon, nitrogen, phosphorus, redox-active metals, and organic contaminants; (2) interactions between microbial activity and redox state in the near-surface and deep subsurface soil, and biomolecular methods to reveal the role of microbes in the redox processes; (3) the effects of dynamic hydrologic regimes on chemical-species cycling and microbial dynamics; (4) the experimental setups for mimicking different hydrologic regimes at both laboratory and field scales. Finally, we identify the current knowledge gaps related to the study of soil redox dynamics under different hydrologic regimes: (1) fluctuating conditions in the deep subsurface; (2) the use of biomolecular tools to understand soil biogeochemical processes beyond nitrogen; (3) limited current field measurements and potential alternative experimental setups.
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Affiliation(s)
- Zengyu Zhang
- Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel
| | - Alex Furman
- Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
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3
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Karthikeyan S, Kim M, Heritier-Robbins P, Hatt JK, Spain JC, Overholt WA, Huettel M, Kostka JE, Konstantinidis KT. Integrated Omics Elucidate the Mechanisms Driving the Rapid Biodegradation of Deepwater Horizon Oil in Intertidal Sediments Undergoing Oxic-Anoxic Cycles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:10088-10099. [PMID: 32667785 DOI: 10.1021/acs.est.0c02834] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Crude oil buried in intertidal sands may be exposed to alternating oxic and anoxic conditions but the effect of this tidally induced biogeochemical oscillation remains poorly understood, limiting the effectiveness of remediation and managing efforts after oil spills. Here, we used a combination of metatranscriptomics and genome-resolved metagenomics to study microbial activities in oil-contaminated sediments during oxic-anoxic cycles in laboratory chambers that closely emulated in situ conditions. Approximately 5-fold higher reductions in the total petroleum hydrocarbons were observed in the oxic as compared to the anoxic phases with a relatively constant ratio between aerobic and anaerobic oil decomposition rates even after prolonged anoxic conditions. Metatranscriptomics analysis indicated that the oxic phases promoted oil biodegradation in subsequent anoxic phases by microbially mediated reoxidation of alternative electron acceptors like sulfide and by providing degradation-limiting nitrogen through biological nitrogen fixation. Most population genomes reconstructed from the mesocosm samples represented uncultured taxa and were present typically as members of the rare biosphere in metagenomic data from uncontaminated field samples, implying that the intertidal communities are adapted to changes in redox conditions. Collectively, these results have important implications for enhancing oil spill remediation efforts in beach sands and coastal sediments and underscore the role of uncultured taxa in such efforts.
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Affiliation(s)
- Smruthi Karthikeyan
- Department of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta 30332-0002, Georgia, United States
| | - Minjae Kim
- Department of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta 30332-0002, Georgia, United States
| | - Patrick Heritier-Robbins
- Department of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta 30332-0002, Georgia, United States
| | - Janet K Hatt
- Department of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta 30332-0002, Georgia, United States
| | - Jim C Spain
- Center for Environmental Diagnostics & Bioremediation, University of West Florida, 11000 University Parkway, Pensacola 32514, Florida, United States
| | - Will A Overholt
- School of Biological Sciences, Georgia Institute of Technology, Atlanta 30332-0002, Georgia, United States
| | - Markus Huettel
- Department of Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee 32306-4320, Florida, United States
| | - Joel E Kostka
- School of Biological Sciences, Georgia Institute of Technology, Atlanta 30332-0002, Georgia, United States
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta 30332-0002, Georgia, United States
| | - Konstantinos T Konstantinidis
- Department of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta 30332-0002, Georgia, United States
- School of Biological Sciences, Georgia Institute of Technology, Atlanta 30332-0002, Georgia, United States
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4
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The Spatial Distribution of the Microbial Community in a Contaminated Aquitard below an Industrial Zone. WATER 2019. [DOI: 10.3390/w11102128] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The industrial complex Neot Hovav, in Israel, is situated above an anaerobic fractured chalk aquitard, which is polluted by a wide variety of hazardous organic compounds. These include volatile and non-volatile, halogenated, organic compounds. In this study, we characterized the indigenous bacterial population in 17 boreholes of the groundwater environment, while observing the spatial variations in the population and structure as a function of distance from the polluting source. In addition, the de-halogenating potential of the microbial groundwater population was tested through a series of lab microcosm experiments, thus exemplifying the potential and limitations for bioremediation of the site. In all samples, the dominant phylum was Proteobacteria. In the production plant area, the non-obligatory organo-halide respiring bacteria (OHRB) Firmicutes Phylum was also detected in the polluted water, in abundancies of up to 16 %. Non-metric multidimensional scaling (NMDS) analysis of the microbial community structure in the groundwater exhibited clusters of distinct populations following the location in the industrial complex and distance from the polluting source. Dehalogenation of halogenated ethylene was demonstrated in contrast to the persistence of brominated alcohols. Persistence is likely due to the chemical characteristics of brominated alcohols, and not because of the absence of active de-halogenating bacteria.
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Sookhak Lari K, Davis GB, Rayner JL, Bastow TP, Puzon GJ. Natural source zone depletion of LNAPL: A critical review supporting modelling approaches. WATER RESEARCH 2019; 157:630-646. [PMID: 31004979 DOI: 10.1016/j.watres.2019.04.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 03/23/2019] [Accepted: 04/01/2019] [Indexed: 06/09/2023]
Abstract
Natural source zone depletion (NSZD) of light non-aqueous phase liquids (LNAPLs) includes partitioning, transport and degradation of LNAPL components. NSZD is being considered as a site closure option during later stages of active remediation of LNAPL contaminated sites, and where LNAPL mass removal is limiting. To ensure NSZD meets compliance criteria and to design enhanced NSZD actions if required, residual risks posed by LNAPL and its long term behaviour require estimation. Prediction of long-term NSZD trends requires linking physicochemical partitioning and transport processes with bioprocesses at multiple scales within a modelling framework. Here we expand and build on the knowledge base of a recent review of NSZD, to establish the key processes and understanding required to model NSZD long term. We describe key challenges to our understanding, inclusive of the dominance of methanogenic or aerobic biodegradation processes, the potentially changeability of rates due to the weathering profile of LNAPL product types and ages, and linkages to underlying bioprocesses. We critically discuss different scales in subsurface simulation and modelling of NSZD. Focusing on processes at Darcy scale, 36 models addressing processes of importance to NSZD are investigated. We investigate the capabilities of models to accommodate more than 20 subsurface transport and transformation phenomena and present comparisons in several tables. We discuss the applicability of each group of models for specific site conditions.
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Affiliation(s)
- Kaveh Sookhak Lari
- CSIRO Land and Water, Private Bag No. 5, Wembley, WA, 6913, Australia; School of Engineering, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA, 6027, Australia.
| | - Greg B Davis
- CSIRO Land and Water, Private Bag No. 5, Wembley, WA, 6913, Australia; School of Earth Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - John L Rayner
- CSIRO Land and Water, Private Bag No. 5, Wembley, WA, 6913, Australia
| | - Trevor P Bastow
- CSIRO Land and Water, Private Bag No. 5, Wembley, WA, 6913, Australia
| | - Geoffrey J Puzon
- CSIRO Land and Water, Private Bag No. 5, Wembley, WA, 6913, Australia
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O'Connor D, Pan S, Shen Z, Song Y, Jin Y, Wu WM, Hou D. Microplastics undergo accelerated vertical migration in sand soil due to small size and wet-dry cycles. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 249:527-534. [PMID: 30928524 DOI: 10.1016/j.envpol.2019.03.092] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 03/22/2019] [Accepted: 03/22/2019] [Indexed: 05/26/2023]
Abstract
Microplastics (MPs) are an emerging concern and potential risk to marine and terrestrial environments. Surface soils are reported to act as a sink. However, MP vertical mobility in the subsurface remains uncertain due to a lack of scientific data. This study focused on MP penetration in sand soil column experiments. Here we report the mobility of five different MPs, which consisted of polyethylene (PE) and polypropylene (PP) particles of various sizes and densities. We observed that the smallest sized PE MPs (21 μm) had the greatest movement potential. Moreover, it was found that when these MPs were subjected to greater numbers of wet-dry cycles, the penetration depth significantly increased, with an apparent linear relationship between depth and wet-dry cycle number (r2 = 0.817). In comparison, increasing the volume of infiltration liquid or the surface MP concentration had only negligible or weak effects on migration depth (r2 = 0.169 and 0.312, respectively). Based on the observed wet-dry cycle trend, we forecast 100-year penetration depths using weather data for 347 cities across China. The average penetration depth was calculated as 5.24 m (95% CI = 2.78-7.70 m), with Beijing Municipality and Hebei, Henan and Hubei provinces being the most vulnerable to MP vertical dispersion. Our results suggest that soils may not only represent a sink for MPs, but also a feasible entryway to subsurface receptors, such as subterranean fauna or aquifers. Finally, research gaps are identified and suggested research directions are put forward to garner a better understanding MP vertical migration in soil.
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Affiliation(s)
- David O'Connor
- School of Environment, Tsinghua University, Beijing, 100084, China
| | - Shizhen Pan
- School of Environment, Tsinghua University, Beijing, 100084, China
| | - Zhengtao Shen
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, T6G 2E3, Canada
| | - Yinan Song
- School of Environment, Tsinghua University, Beijing, 100084, China
| | - Yuanliang Jin
- School of Environment, Tsinghua University, Beijing, 100084, China
| | - Wei-Min Wu
- Department of Civil and Environmental Engineering, William & Cloy Codiga Resource Recovery Center, Center for Sustainable Development & Global Competitiveness, Stanford University, Stanford, CA, 94305-4020, USA
| | - Deyi Hou
- School of Environment, Tsinghua University, Beijing, 100084, China.
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Yao Y, Mao F, Xiao Y, Luo J. Modeling capillary fringe effect on petroleum vapor intrusion from groundwater contamination. WATER RESEARCH 2019; 150:111-119. [PMID: 30508708 DOI: 10.1016/j.watres.2018.11.038] [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: 08/10/2018] [Revised: 11/06/2018] [Accepted: 11/16/2018] [Indexed: 06/09/2023]
Abstract
At contaminated sites, indoor inhalation of volatile organic compounds from groundwater contamination, known as vapor intrusion (VI), is an important exposure pathway to determine groundwater cleanup level. Based on empirical analysis, US EPA concluded that there is a low probability for vapors from fuel hydrocarbons dissolved in groundwater to induce indoor concentrations that exceed risk-based standards, and recommended 6 feet vertical building-source separation distance as the risk screening tool for such cases. In this study, we examine this recommendation by performing numerical modeling to investigate the detailed effects of the capillary fringe on petroleum vapor biodegradation and attenuation. First, the numerical model is validated by comparison with laboratory data and field measurements in US EPA's database. Then the verified model is used to simulate two scenarios involving the capillary fringe effect, one with a groundwater source at various depth and the other with a soil gas source located above the groundwater level. For a groundwater contaminant source, the capillary fringe plays a significant role in VI by controlling the soil moisture content and oxygen availability, thus affecting the soil gas concentration biodegradation and attenuation. Specifically, the capillary fringe effect can significantly decrease the indoor air concentration by decreasing upward diffusion rates of hydrocarbon, increasing the thickness of the aerobic zone, and enhancing aerobic biodegradation. As a result, it is highly unlikely for sources located at groundwater level to induce unacceptable vapor intrusion risks, supporting US EPA's recommendation. Moreover, the simulations suggest that the vertical smear zone of residual light non-aqueous liquid contamination, induced by temporal fluctuations of groundwater level, may lead to a potential threat to indoor air quality for a short vertical source-building separation distance, and thus requires more attention. The sensitivity test of the numerical model also indicates that it is the vertical separation distance between building foundation and the top of the smear zone instead of the smear zone thickness that should be given more attention during the investigation.
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Affiliation(s)
- Yijun Yao
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Research Center for Air Pollution and Health, Zhejiang University, Hangzhou, 310058, China; Institute of Environmental Health, Zhejiang University, Hangzhou, 310058, China.
| | - Fang Mao
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Research Center for Air Pollution and Health, Zhejiang University, Hangzhou, 310058, China; Institute of Environmental Health, Zhejiang University, Hangzhou, 310058, China
| | - Yuting Xiao
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Research Center for Air Pollution and Health, Zhejiang University, Hangzhou, 310058, China; Institute of Environmental Health, Zhejiang University, Hangzhou, 310058, China
| | - Jian Luo
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
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Ma Y, Dong B, Bai Y, Zhang M, Xie Y, Shi Y, Du X. Remediation status and practices for contaminated sites in China: survey-based analysis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:33216-33224. [PMID: 30255269 DOI: 10.1007/s11356-018-3294-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 09/18/2018] [Indexed: 06/08/2023]
Abstract
This study aims to determine the current remediation status of contaminated sites in China to support future decision-making for the cleanup of contaminated sites. A survey was conducted in which a questionnaire was administered to 76 remediation practitioners working across China. The major driving force behind remediation was the redevelopment of contaminated brownfield land for residential purposes, mostly funded by profit-driven developers, particularly in Beijing. A large proportion of brownfield sites have been contaminated with organic compounds, reflecting past land use by chemical plants. Risk assessments of contaminated sites are typically based on the guidelines from China's Ministry of Ecology and Environment, the United States Environmental Protection Agency, and local governments. The most frequently used criteria to assess site contamination in China are environmental quality standards, screening values, or both. The majority of remediation efforts use low-technology approaches to treat contaminated soil (e.g., cement kiln, in situ and ex situ solidification/stabilization, landfill, and mechanical soil aeration), while sophisticated, high-technology approaches (e.g., in situ and ex situ thermal desorption, in situ chemical treatment, and bioventing) are less often used. The implementation of the latter, while limited, illustrates that the necessary technology exists to support optimal land remediation in China. In addition to high-technology remediation methods, 6W/1H ideology can be employed when assessing contaminated site for remediation. Graphical abstract ᅟ.
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Affiliation(s)
- Yan Ma
- School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing, 100083, People's Republic of China
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China
| | - Binbin Dong
- Beijing Solid Waste Treatment Co. Ltd., Beijing, 100101, People's Republic of China
| | - Yanying Bai
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China
| | - Meng Zhang
- School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing, 100083, People's Republic of China
| | - Yunfeng Xie
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China
| | - Yi Shi
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China
| | - Xiaoming Du
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China.
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O'Connor D, Hou D, Ok YS, Song Y, Sarmah AK, Li X, Tack FM. Sustainable in situ remediation of recalcitrant organic pollutants in groundwater with controlled release materials: A review. J Control Release 2018; 283:200-213. [DOI: 10.1016/j.jconrel.2018.06.007] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/02/2018] [Accepted: 06/04/2018] [Indexed: 11/29/2022]
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10
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Gassen N, Griebler C, Werban U, Trauth N, Stumpp C. High Resolution Monitoring Above and Below the Groundwater Table Uncovers Small-Scale Hydrochemical Gradients. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:13806-13815. [PMID: 29131645 DOI: 10.1021/acs.est.7b03087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Hydrochemical solute concentrations in the shallow subsurface can be spatially highly variable within small scales, particularly at interfaces. However, most monitoring systems fail to capture these small scale variations. Within this study, we developed a high resolution multilevel well (HR-MLW) with which we monitored water across the interface of the unsaturated and saturated zone with a vertical resolution of 0.05-0.5 m. We installed three of these 4 m deep HR-MLWs in the riparian zone of a third-order river and analyzed for hydrochemical parameters and stable water isotopes. The results showed three distinct vertical zones (unsaturated zone, upper saturated zone, lower saturated zone) within the alluvial aquifer. A 2 m thick layer influenced by river water (upper saturated zone) was not captured by existing monitoring wells with higher screen length. Hydrochemical data (isotopes, total ions) were consistent in all HR-MLWs and showed similar variation over time emphasizing the reliability of the installed monitoring system. Further, the depths zones were also reflected in the NO3-N concentrations; with high spatial variabilities between the three wells. The zonation was constant over time, with seasonal variability in the upper saturated zone due to the influence of river water. This study highlights the use of high resolution monitoring for identifying the spatial and temporal variability of hydrochemical parameters present in many aquifer systems. Possible applications range from riparian zones, agricultural field sites to contaminated site studies, wherever an improved understanding of biogeochemical turnover processes is necessary.
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Affiliation(s)
- N Gassen
- Institute of Groundwater Ecology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) , Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - C Griebler
- Institute of Groundwater Ecology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) , Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - U Werban
- Department Monitoring and Exploration Technologies, Helmholtz Center for Environmental Research - UFZ , Permoserstrasse 15, 04318 Leipzig, Germany
| | - N Trauth
- Department of Hydrogeology, Helmholtz Center for Environmental Research - UFZ , Permoserstrasse 15, 04318 Leipzig, Germany
| | - C Stumpp
- Institute of Groundwater Ecology, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) , Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
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Kurt Z, Mack EE, Spain JC. Natural Attenuation of Nonvolatile Contaminants in the Capillary Fringe. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:10172-10178. [PMID: 27523982 DOI: 10.1021/acs.est.6b02525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
When anoxic polluted groundwater encounters the overlying vadose zone an oxic/anoxic interface is created, often near the capillary fringe. Biodegradation of volatile contaminants in the capillary fringe can prevent vapor migration. In contrast, the biodegradation of nonvolatile contaminants in the vadose zone has received comparatively little attention. Nonvolatile compounds do not cause vapor intrusion, but they still move with the groundwater and are major contaminants. Aniline (AN) and diphenylamine (DPA) are examples of toxic nonvolatile contaminants found often at dye and munitions manufacturing sites. In this study, we tested the hypothesis that bacteria can aerobically biodegrade AN and DPA in the capillary fringe and decrease the contaminant concentrations in the anoxic plume beneath the vadose zone. Laboratory multiport columns that represented the unsaturated zone were used to evaluate degradation of AN or DPA in contaminated water. The biodegradation fluxes of the contaminants were estimated to be 113 ± 26 mg AN·m(-2)·h(-1) and 76 ± 18 mg DPA·m(-2)·h(-1) in the presence of bacteria known to degrade AN and DPA. Oxygen and contaminant profiles along with enumeration of bacterial populations indicated that most of the biodegradation took place within the lower part of the capillary fringe. The results indicate that bacteria capable of contaminant biodegradation in the capillary fringe can create a sink for nonvolatile contaminants.
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Affiliation(s)
- Zohre Kurt
- School of Civil and Environmental Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332-0512, United States
- Institute of Scientific Research and High Technology Services , Calle Pullpn, Panamá, Panama
| | - E Erin Mack
- DuPont, Corporate Remediation Group, P.O. Box 6101, Glasgow 300, Newark, Delaware 19714-6101, United States
| | - Jim C Spain
- School of Civil and Environmental Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332-0512, United States
- Center for Environmental Diagnostics and Bioremediation, University of West Florida , Pensacola, Florida 32514-5751, United States
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12
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Chen Y, Hou D, Lu C, Spain JC, Luo J. Effects of Rate-Limited Mass Transfer on Modeling Vapor Intrusion with Aerobic Biodegradation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:9400-9406. [PMID: 27486832 DOI: 10.1021/acs.est.6b01840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Most of the models for simulating vapor intrusion accept the local equilibrium assumption for multiphase concentration distributions, that is, concentrations in solid, liquid and vapor phases are in equilibrium. For simulating vapor transport with aerobic biodegradation controlled by counter-diffusion processes, the local equilibrium assumption combined with dual-Monod kinetics and biomass decay may yield near-instantaneous behavior at steady state. The present research investigates how predicted concentration profiles and fluxes change as interphase mass transfer resistances are increased for vapor intrusion with aerobic biodegradation. Our modeling results indicate that the attenuation coefficients for cases with and without mass transfer limitations can be significantly different by orders of magnitude. Rate-limited mass transfer may lead to larger overlaps of contaminant vapor and oxygen concentrations, which cannot be simulated by instantaneous reaction models with local equilibrium mass transfer. In addition, the contaminant flux with rate-limited mass transfer is much smaller than that with local equilibrium mass transfer, indicating that local equilibrium mass transfer assumption may significantly overestimate the biodegradation rate and capacity for mitigating vapor intrusion through the unsaturated zone. Our results indicate a strong research need for field tests to examine the validity of local equilibrium mass transfer, a widely accepted assumption in modeling vapor intrusion.
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Affiliation(s)
- Yiming Chen
- School of Civil and Environmental Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332-0355, United States
| | - Deyi Hou
- School of Environment, Tsinghua University , Beijing, China
| | - Chunhui Lu
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University , Nanjing, China
| | - Jim C Spain
- Center for Environmental Diagnostics & Bioremediation, University of West Florida , Pensacola, Florida 32514-5751, United States
| | - Jian Luo
- School of Civil and Environmental Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332-0355, United States
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