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Gong Y, Liu Z, Ma C, Li M, Guo X. Experimental Study on the Lateral Seepage Characteristics in the Tension Saturated Zone. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18105098. [PMID: 34065824 PMCID: PMC8151663 DOI: 10.3390/ijerph18105098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 11/20/2022]
Abstract
To study the lateral seepage field in the tension saturated zone (TSZ), an experiment with no evaporation and precipitation infiltration was carried out in a self-made seepage tank filled up with fine sand. Based on the data and plots obtained, the lateral seepage field distribution features in the TSZ can be divided into three area for discussion: ascending area, descending area, and the nearly horizontal flow area. In the ascending and descending area, the total water potential gradient diminished from the recharge area to the discharge area and the seepage velocity was faster. In the nearly horizontal flow area, the total water potential gradient was lower and the seepage velocity was slower. The pressure potential gradually decreased horizontally from the recharge area to the discharge area, while in the vertical profile, it gradually decreased from the bottom to the top in the whole seepage area. In the absence of evaporation, the vertical water exchange among the saturated zone, TSZ, and unsaturated zone in nearly horizontal flow area is weak. Contrarily, in the ascending area and descending area, vertical water flows through both the phreatic surface and the upper interface of the TSZ. When there is lateral seepage in the TSZ, the thickness of the TSZ generally increases from the ascending area to the nearly horizontal area and then to the descending area. It should be pointed out that in the nearly horizontal area, the TSZ thickness is approximately equal to the height of the water column. Overall, the lateral seepage in the TSZ can be regarded as a stable siphon process, hence the siphon tube model can be further used to depict this lateral seepage.
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Affiliation(s)
- Yongfeng Gong
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, China; (Y.G.); (Z.L.); (C.M.); (M.L.)
- Ningxia Institute of Land and Resources and Monitoring, Yinchuan 750002, China
| | - Zuo Liu
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, China; (Y.G.); (Z.L.); (C.M.); (M.L.)
| | - Chuanming Ma
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, China; (Y.G.); (Z.L.); (C.M.); (M.L.)
| | - Minghong Li
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, China; (Y.G.); (Z.L.); (C.M.); (M.L.)
| | - Xu Guo
- School of Environmental Studies, China University of Geosciences, Wuhan 430074, China; (Y.G.); (Z.L.); (C.M.); (M.L.)
- Correspondence: ; Tel.: +86-27-6788-3159
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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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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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Rogowska J, Sychowska J, Cieszynska-Semenowicz M, Wolska L. Elemental sulfur in sediments: analytical problems. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:24871-24879. [PMID: 27662854 DOI: 10.1007/s11356-016-7739-1] [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: 03/18/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
In the paper, a modified method for elemental sulfur (S8) determining using gas chromatography coupled with mass spectrometry (GC-MS) is proposed with estimation of selected validation parameters. The aim of this work was a review of problems associated with the determination of S8 and selection of the most optimal conditions for S8 analysis with GC-MS. The presented studies have shown that the temperature of the injector and the chromatographic column during S8 determination should not exceed 180 °C. At temperatures over 180 °C, the sulfur S8 is decomposed to the other sulfur species such as S2, S3, S4, S5, and S6. During decreasing injector and column temperature below 180 °C the chromatographic peak eluted as S8 is badly extended and asymmetric. To minimize the problems of S8 decomposition to other sulfur species during chromatographic process also other parameters of the GC-MS have been selected. In order to apply the proposed method for real sediments samples, determination of sulfur S8 in bottom sediments, collected in the Gulf of Gdansk (southern Baltic Sea), has been performed. The concentration of S8 fell in the range from below the limit of detection to 0.1432 ± 0.0095 mg/g d.w. The research has also shown that addition of approx. 200 mg of activated copper is effective for removing sulfur from bottom sediment extracts.
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Affiliation(s)
- Justyna Rogowska
- Department of Environmental Toxicology, Faculty of Health Sciences, Medical University of Gdansk, 80-204 Gdansk, 23 Debowa Str, Gdansk, Poland.
| | - Joanna Sychowska
- Department of Environmental Toxicology, Faculty of Health Sciences, Medical University of Gdansk, 80-204 Gdansk, 23 Debowa Str, Gdansk, Poland
| | - Monika Cieszynska-Semenowicz
- Department of Environmental Toxicology, Faculty of Health Sciences, Medical University of Gdansk, 80-204 Gdansk, 23 Debowa Str, Gdansk, Poland
| | - Lidia Wolska
- Department of Environmental Toxicology, Faculty of Health Sciences, Medical University of Gdansk, 80-204 Gdansk, 23 Debowa Str, Gdansk, Poland
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Tischer K, Kleinsteuber S, Schleinitz KM, Fetzer I, Spott O, Stange F, Lohse U, Franz J, Neumann F, Gerling S, Schmidt C, Hasselwander E, Harms H, Wendeberg A. Microbial communities along biogeochemical gradients in a hydrocarbon-contaminated aquifer. Environ Microbiol 2013; 15:2603-15. [DOI: 10.1111/1462-2920.12168] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 05/21/2013] [Accepted: 05/25/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Karolin Tischer
- Department of Environmental Microbiology; Helmholtz Centre for Environmental Research - UFZ; Permoserstr. 15; 04318; Leipzig; Germany
| | - Sabine Kleinsteuber
- Department of Environmental Microbiology; Helmholtz Centre for Environmental Research - UFZ; Permoserstr. 15; 04318; Leipzig; Germany
| | - Kathleen M. Schleinitz
- Department of Environmental Microbiology; Helmholtz Centre for Environmental Research - UFZ; Permoserstr. 15; 04318; Leipzig; Germany
| | | | - Oliver Spott
- Department of Soil Physics; Helmholtz Centre for Environmental Research - UFZ; Theodor-Lieser-Str. 4; 06120; Halle/Saale; Germany
| | - Florian Stange
- Federal Institute for Geosciences and Natural Resources; Stilleweg 2; 30655; Hannover; Germany
| | - Ute Lohse
- Department of Environmental Microbiology; Helmholtz Centre for Environmental Research - UFZ; Permoserstr. 15; 04318; Leipzig; Germany
| | | | | | - Sarah Gerling
- Department of Environmental Microbiology; Helmholtz Centre for Environmental Research - UFZ; Permoserstr. 15; 04318; Leipzig; Germany
| | - Christian Schmidt
- Department of Hydrogeology; Helmholtz Centre for Environmental Research - UFZ; Permoserstr. 15; 04318; Leipzig; Germany
| | - Eyk Hasselwander
- G.U.T. Gesellschaft für Umweltsanierungs-Technologien mbH; Gerichtshain 1; 06217; Merseburg; Germany
| | - Hauke Harms
- Department of Environmental Microbiology; Helmholtz Centre for Environmental Research - UFZ; Permoserstr. 15; 04318; Leipzig; Germany
| | - Annelie Wendeberg
- Department of Environmental Microbiology; Helmholtz Centre for Environmental Research - UFZ; Permoserstr. 15; 04318; Leipzig; Germany
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