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Tran THH, Kim SH, Kim HB, Kwon MJ, Chung J, Lee S. Prediction of arsenic retention in vadose zone based on empirical relationship between soil properties and segmented retardation factors. JOURNAL OF HAZARDOUS MATERIALS 2024; 476:134990. [PMID: 38908179 DOI: 10.1016/j.jhazmat.2024.134990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 06/07/2024] [Accepted: 06/19/2024] [Indexed: 06/24/2024]
Abstract
Arsenic (As) is a widespread environmental contaminant that poses a significant threat to ecosystems and human health. Although previous studies have qualitatively revealed the effects of individual soil properties on the transport and fate of As in the vadose zone, their integrated impacts remain obscure. Moreover, studies investigating the retardation factor therein, which is a key parameter for comprehending As transport in the vadose zone, are extremely limited. In this study, we investigated the interplay of soil properties with As transport and retention within the vadose zone, while focusing on the retardation factor of As. We employed steady-state unsaturated water-flow soil column experiments coupled with a mobile-immobile model and multiple linear regression analysis to elucidate the dependence of As retardation factors on the soil properties. In the mobile water zone, iron and organic matter contents emerged as the two most influential properties that impedes As mobility. Whereas, in the immobile water zone, the coefficient of uniformity and bulk density were the most influential factors that enhanced As retention. Finally, we derived an empirical equation for calculating the As retardation factors in each zone, offering a valuable tool for describing and predicting As behavior to protect the groundwater resources underneath.
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Affiliation(s)
- Tho Huu Huynh Tran
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, the Republic of Korea; Division of Energy and Environment Technology, KIST School, Korea University of Science and Technology, Seoul 02792, the Republic of Korea
| | - Sang Hyun Kim
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, the Republic of Korea; Division of Energy and Environment Technology, KIST School, Korea University of Science and Technology, Seoul 02792, the Republic of Korea
| | - Hye-Bin Kim
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, the Republic of Korea
| | - Man Jae Kwon
- Department of Earth and Environmental Science, Korea University, Seoul 02841, the Republic of Korea
| | - Jaeshik Chung
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, the Republic of Korea; Division of Energy and Environment Technology, KIST School, Korea University of Science and Technology, Seoul 02792, the Republic of Korea.
| | - Seunghak Lee
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, the Republic of Korea; Division of Energy and Environment Technology, KIST School, Korea University of Science and Technology, Seoul 02792, the Republic of Korea; Graduate School of Energy and Environment (KU-KIST Green School), Korea University, Seoul 02841, the Republic of Korea.
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Lussich F, Dhaliwal JK, Faiia AM, Jagadamma S, Schaeffer SM, Saha D. Cover crop residue decomposition triggered soil oxygen depletion and promoted nitrous oxide emissions. Sci Rep 2024; 14:8437. [PMID: 38600170 PMCID: PMC11006885 DOI: 10.1038/s41598-024-58942-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 04/04/2024] [Indexed: 04/12/2024] Open
Abstract
Cover cropping is a promising strategy to improve soil health, but it may also trigger greenhouse gas emissions, especially nitrous oxide (N2O). Beyond nitrogen (N) availability, cover crop residue decomposition may accelerate heterotrophic respiration to limit soil O2 availability, hence promote N2O emissions from denitrification under sub-optimal water-filled pore space (WFPS) conditions that are typically not conducive to large N2O production. We conducted a 21-day incubation experiment to examine the effects of contrasting cover crop residue (grass vs legume) decomposition on soil O2 and biogeochemical changes to influence N2O and CO2 emissions from 15N labeled fertilized soils under 50% and 80% WFPS levels. Irrespective of cover crop type, mixing cover crop residue with N fertilizer resulted in high cumulative N2O emissions under both WFPS conditions. In the absence of cover crop residues, the N fertilizer effect of N2O was only realized under 80% WFPS, whereas it was comparable to the control under 50% WFPS. The N2O peaks under 50% WFPS coincided with soil O2 depletion and concomitant high CO2 emissions when cover crop residues were mixed with N fertilizer. While N fertilizer largely contributed to the total N2O emissions from the cover crop treatments, soil organic matter and/or cover crop residue derived N2O had a greater contribution under 50% than 80% WFPS. Our results underscore the importance of N2O emissions from cover crop-based fertilized systems under relatively lower WFPS via a mechanism of respiration-induced anoxia and highlight potential risks of underestimating N2O emissions under sole reliance on WFPS.
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Affiliation(s)
- Facundo Lussich
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, 37996, USA
| | - Jashanjeet Kaur Dhaliwal
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, 37996, USA
| | - Anthony M Faiia
- Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN, 37996, USA
| | - Sindhu Jagadamma
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, 37996, USA
| | - Sean M Schaeffer
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, 37996, USA
| | - Debasish Saha
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN, 37996, USA.
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Anggraini TM, An S, Kim SH, Kwon MJ, Chung J, Lee S. Influence of iron (hydr)oxide mineralogy and contents in aquifer sediments on dissolved organic carbon attenuations during aquifer storage and recovery. CHEMOSPHERE 2024; 351:141196. [PMID: 38218241 DOI: 10.1016/j.chemosphere.2024.141196] [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: 09/03/2023] [Revised: 12/29/2023] [Accepted: 01/10/2024] [Indexed: 01/15/2024]
Abstract
Aquifer storage and recovery (ASR) is a promising approach for managing water resources that enhances water quality through biogeochemical reactions occurring within aquifers. Iron (hydr)oxides, which are the predominant metallic oxides in soil, play a crucial role in degrading dissolved organic carbon (DOC), primarily through a process known as dissimilatory iron reduction (DIR). However, the efficiency of this reaction varies depending on the mineralogy and composition of the aquifer, and this understanding is essential for adequate water quality in ASR. The objective of this study is to investigate the impact of iron (hydr)oxide on acetate, as an organic carbon source, attenuation during the ASR. To achieve this, three sets of laboratory sediment columns were prepared, each containing a different type of iron (hydr)oxide minerals: ferrihydrite, goethite, and hematite. Following an acclimation period of 28 days to simulate the microcosm within an aquifer, the columns were continuously supplied with the simulated river water spiked with acetate (DOC 40-60 mg L-1), and the acetate concentration in the effluent was monitored. The result revealed that the column containing ferrihydrite achieved 97% acetate attenuation through DIR with anoxic conditions (DO < 0.1 mg L-1), while the goethite and hematite columns exhibited limited attenuation rates of 40 and 50%, respectively. Furthermore, the efficiency of acetate attenuation in the ferrihydrite columns increased with the content of ferrihydrite but experienced a rapidly declined at higher contents (3-4%), possibly due to the partial conversion of ferrihydrite to goethite as a result of the interaction between ferrihydrite and the Fe(II) produced during DIR. Additionally, an analysis of the microbial community demonstrated that microorganisms known to possess the ability to reduce iron (hydr)oxides under anaerobic conditions were abundant in the ferrihydrite columns.
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Affiliation(s)
- Theresia May Anggraini
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, Republic of Korea
| | - Seongnam An
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Sang Hyun Kim
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, Republic of Korea
| | - Man Jae Kwon
- Department of Earth and Environmental Sciences, Korea University, Seoul, 02841, Republic of Korea
| | - Jaeshik Chung
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, Republic of Korea.
| | - Seunghak Lee
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, Republic of Korea; Graduate School of Energy and Environment (KU-KIST GREEN SCHOOL), Korea University, Seoul, 02841, Republic of Korea.
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An S, Kim SH, Woo H, Choi JW, Yun ST, Chung J, Lee S. Groundwater-level fluctuation effects on petroleum hydrocarbons in vadose zones and their potential risks: Laboratory studies. JOURNAL OF HAZARDOUS MATERIALS 2024; 463:132837. [PMID: 37890385 DOI: 10.1016/j.jhazmat.2023.132837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/10/2023] [Accepted: 10/20/2023] [Indexed: 10/29/2023]
Abstract
Despite the role of the vadose zone protecting groundwater from contamination, the non-stationarity in this zone makes it difficult to predict the behavior of petroleum hydrocarbons (PH) therein. In laboratory soil columns with sandy and sandy loam soils, we simulated a vadose zone subjected to repeated groundwater-level fluctuation (GLF) to evaluate the behavior of PH under hydrodynamic conditions. The GLF vertically redistributed the PH, the extent of which was pronounced in the sandy soil with a high initial concentration due to the enhanced transport of the immiscible PH through the larger pores. The frequency of GLF did not show a substantial effect on the extent of PH redistribution but largely affected their attenuation. The greater GLF hindered PH volatilization by maintaining a high degree of water saturation, while the subsequent development of a local anaerobic regime inhibited biodegradation, which was more apparent in the sandy loam. Finally, a specific potential risk index was introduced to quantitatively compare the potential risk of PH contamination in different vadose zones exposed to GLF. Overall, the sandy soil contaminated with the higher total PH (TPH) concentration showed markedly higher potential risk indices (i.e., 18.4-29.0%), while the ones comprised of the sandy loam showed 0.6-4.9%, which increased under the greater number of GLF cycles.
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Affiliation(s)
- Seongnam An
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Sang Hyun Kim
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Energy and Environmental Technology, KIST School, Korea University of Science and Technology (UST), Seoul 02792, Republic of Korea
| | - Heesoo Woo
- Geo-technical Team, ECO Solution Business Unit, SK Ecoplant, Seoul 03143, Republic of Korea
| | - Jae Woo Choi
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Energy and Environmental Technology, KIST School, Korea University of Science and Technology (UST), Seoul 02792, Republic of Korea
| | - Seong-Taek Yun
- Department of Earth and Environmental Sciences, Korea University, Seoul 136-701, Republic of Korea
| | - Jaeshik Chung
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Energy and Environmental Technology, KIST School, Korea University of Science and Technology (UST), Seoul 02792, Republic of Korea.
| | - Seunghak Lee
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Energy and Environmental Technology, KIST School, Korea University of Science and Technology (UST), Seoul 02792, Republic of Korea; Graduate School of Energy and Environment (KU-KIST GREEN SCHOOL), Korea University, Seoul 02841, Republic of Korea.
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Chen S, Kuramae EE, Jia Z, Liu B. Stable isotope probing reveals compositional and functional shifts in active denitrifying communities along the soil profile in an intensive agricultural area. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 907:167968. [PMID: 37875201 DOI: 10.1016/j.scitotenv.2023.167968] [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: 08/14/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 10/26/2023]
Abstract
Denitrifying microbial communities in the vadose zone play an essential role in eliminating the nitrate leached from agricultural practices. This nitrate could otherwise contaminate groundwater and threaten public health. Here, we utilized stable isotope probing combined with amplicon sequencing and functional gene quantification to inspect the composition and function of heterotrophic denitrifying microorganisms along a 9-m soil profile in an intensive agricultural area. Dramatic differences in the composition of the active denitrifiers were uncovered between the surface soil and deep layers of the vadose zone. The main denitrifying bacterial taxa identified from 13C-DNA fractions were Pseudomonadaceae (Pseudomonas), Rhodocyclaceae (Azoarcus), and Burkholderiaceae in the surface soil (0-0.2 m), and were Pseudomonadaceae (Pseudomonas), Burkholderiaceae, Bacillaceae (Bacillus), and Paenibacillaceae (Ammoniphilus) in the deep layers (0.5-9.0 m). Analysis of the functional genes (nirS, nirK, and nosZ) in isotope-labeled DNA revealed an upward nos/nir ratio with increasing soil depth, which may account for the higher nitrous oxide emission potential in the surface soil, as compared to the deeper sand-rich, low organic carbon layers. This study improves our understanding of active denitrifying microbes in the vadose zone and helps in developing techniques to reduce nitrate pollution in groundwater.
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Affiliation(s)
- Shuaimin Chen
- Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang 050021, China; Institute of Agricultural Resource and Environment, Jilin Academy of Agricultural Sciences, 1363 Shengtai Street, Changchun 130033, China; Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 Wageningen, PB, Netherlands
| | - Eiko E Kuramae
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 Wageningen, PB, Netherlands; Ecology and Biodiversity, Institute of Environmental Biology, Utrecht University, Padualaan 8, 10 3584 CH, Utrecht, the Netherlands
| | - Zhongjun Jia
- Key Laboratory of Mollisols Agroecology, State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China
| | - Binbin Liu
- Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang 050021, China.
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Jiang X, Zhong X, Yu G, Zhang X, Liu J. Different effects of taproot and fibrous root crops on pore structure and microbial network in reclaimed soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 901:165996. [PMID: 37536594 DOI: 10.1016/j.scitotenv.2023.165996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/31/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023]
Abstract
Understanding the effects of plant roots on the pore structure and microbial community of soil is crucial to recovery and improve soil productivity in mining areas. This study aims to assess the impact of taproot (TR) and fibrous root (FR) crops on the physicochemical properties, pore structure, and microbial communities and networks in reclaimed mine soil. Results showed that reclamation positively influenced pore structure and microbial diversity. Tillage with TR and FR crops significantly increased porosity, total pore volume, and area of mining soil (p < 0.05). Compared with TR, FR produced more macropores, mesopores, and micropores. In addition, the module group, average degree, density, and connectivity of microbial network in FR cultivated soil were higher than those in TR cultivated soil. The microbial network map showed that FR had more keystone taxa than TR, and mainly consisted of Acidobacteria and Proteobacteria. In the FR microbial network, Rhizobiales, Betaproteobacteria, and Acidobacteria_Gp11 play critical roles as module hubs and Noviherbaspirillum and Zavarzinella as connectors. Furthermore, most of the key microbes were significantly correlated (p < 0.05) with the total pore area and probably tended to live in pores >75 μm and 0.1-5 μm in size. Therefore, FR crops were more effective than TR crops in improving pore structure and enhancing the development of microbial network in reclaimed soil.
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Affiliation(s)
- Xusheng Jiang
- Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, China.
| | - Xuemei Zhong
- College of Earth Sciences, Guilin University of Technology, Guilin 540001, China.
| | - Guo Yu
- Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, China.
| | - Xuehong Zhang
- Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, China.
| | - Jie Liu
- Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, China; Technical Innovation Center of Mine Geological Environmental Restoration Engineering in Southern Karst Area, MNR, Guilin 541004, China.
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Du Y, Guo S, Wang R, Song X, Ju X. Soil pore structure mediates the effects of soil oxygen on the dynamics of greenhouse gases during wetting-drying phases. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 895:165192. [PMID: 37385503 DOI: 10.1016/j.scitotenv.2023.165192] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
The timing and magnitude of greenhouse gas (GHG) production depend strongly on soil oxygen (O2) availability, and the soil pore geometry characteristics largely regulate O2 and moisture conditions relating to GHG biochemical processes. However, the interactions between O2 dynamics and the concentration and flux of GHGs during the soil moisture transitions under various soil pore conditions have not yet been clarified. In this study, a soil-column experiment was conducted under wetting-drying phases using three pore-structure treatments, FINE, MEDIUM, and COARSE, with 0 %, 30 %, and 50 % coarse quartz sand applied to soil, respectively. The concentrations of soil gases (O2, nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4)) were monitored at a depth of 15 cm hourly, and their surface fluxes were measured daily. Soil porosity, pore size distribution, and pore connectivity were quantified using X-ray computed microtomography. The soil O2 concentrations were found to decline sharply as soil moisture increased to the water holding capacities of 0.46, 0.41, and 0.32 cm cm-3 in the FINE, MEDIUM, and COARSE, respectively. The dynamic patterns of the O2 concentrations varied across the soil pore structures, decreasing to anaerobic in FINE (<0.01 %) and MEDIUM (0.02 %), and to hypoxic (4.42 %) in COARSE. Correspondingly, the soil N2O concentration was the highest in FINE (101 μL L-1) and the lowest in COARSE (10 μL L-1), whereas the highest surface N2O flux was observed in MEDIUM (131 μg N m-2 h-1). As soil CO2 concentrations declined, CO2 fluxes increased from FINE to MEDIUM to COARSE. Most pores of FINE, MEDIUM, and COARSE were 15-80 μm, 85-100 μm, and 105-125 μm, respectively, in terms of diameter. The X-ray CT visible (>15 μm) porosity in FINE, MEDIUM and COARSE were 0.09, 0.17, and 0.28 mm3 mm-3, respectively. The corresponding Euler-Poincaré numbers were 180,280, 76,705, and -10,604, respectively, indicating higher connectivity in COARSE than in MEDIUM or FINE. In soil dominated by small air-filled porosity which limits gas diffusion and result in low soil O2 concentration, N2O concentration was increased and CO2 flux was inhibited as the moisture content increased. The turning point in the sharp decrease in O2 concentration was found to correspond with a moisture content, and a pore diameter of 95-110 μm was associated with the critical turning point between holding water and O2 depletion in soil. These findings suggest that O2-regulated biochemical processes are key to the production and flux of GHGs, which in turn are dependent on the soil pore structure and a coupling relationship between N2O and CO2. Improved understanding of the intense effect of soil physical properties provided an empirical foundation for the future development of mechanistic prediction models for how pore-space scale processes with high temporal (hourly) resolution up to GHGs fluxes at larger spatial and temporal scales.
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Affiliation(s)
- Yanling Du
- The Research Center of Soil and Water Conservation and Ecological Environment, Chinese Academy of Sciences and Ministry of Education, Yangling, Shaanxi 712100, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China; University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Shengli Guo
- The Research Center of Soil and Water Conservation and Ecological Environment, Chinese Academy of Sciences and Ministry of Education, Yangling, Shaanxi 712100, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China; University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
| | - Rui Wang
- The Research Center of Soil and Water Conservation and Ecological Environment, Chinese Academy of Sciences and Ministry of Education, Yangling, Shaanxi 712100, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China; University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
| | - Xiaotong Song
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xiaotang Ju
- College of Tropical Crops, Hainan University, Haikou 570228, China
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An S, Woo H, Kim SH, Yun ST, Chung J, Lee S. Complex behavior of petroleum hydrocarbons in vadose zone: A holistic analysis using unsaturated soil columns. CHEMOSPHERE 2023; 326:138417. [PMID: 36925010 DOI: 10.1016/j.chemosphere.2023.138417] [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: 02/01/2023] [Revised: 03/13/2023] [Accepted: 03/13/2023] [Indexed: 06/18/2023]
Abstract
The migration of petroleum hydrocarbons in vadose zone involves complex coupled processes such as downward displacement and natural attenuation. Despite its significance in determining groundwater vulnerability to petroleum contamination and optimizing the remedial strategy, it has not been comprehensively studied in terms of overall processes under field-relevant conditions. In this study, a series of unsaturated soil column experiments were conducted by simulating subsurface diesel contamination within a vadose zone using different soil textures at different soil bulk densities and initial diesel concentrations, while partly exposing them to simulated precipitation. The results showed that the soil column with less fine fraction was favorable for the downward migration of diesel but unfavorable for its natural degradation. However, precipitation complicated the relative conductivities of multiple fluids (water, air, and diesel) through the pore network, therby decreasing diesel migration and degradation. For example, the downward migration of diesel in the SL column decreased by 8.4% under precipitation, while the overall attenuation rate dropped to almost 0.24% of its original state. Lowering bulk density (from 1.5 to 1.23 g/cm3), however, could enhance the attenuation rate presumably due to the secured void space for the incoming fluids. A high initial concentration of diesel (2%; w/w) inhibited its natural attenuation, while its influence on its vertical propagation after the precipitation was not significant. The present findings provide a mechanistic basis for approximating the behavior of petroleum hydrocarbons in a random vadose zone.
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Affiliation(s)
- Seongnam An
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea
| | - Heesoo Woo
- Geo-technical Team, ECO Solution Business Unit, SK Ecoplant, Seoul, 03143, South Korea
| | - Sang Hyun Kim
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea
| | - Seong-Taek Yun
- Department of Earth and Environmental Sciences, Korea University, Seoul, 136-701, South Korea
| | - Jaeshik Chung
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea; Division of Energy and Environmental Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, South Korea.
| | - Seunghak Lee
- Water Cycle Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea; Division of Energy and Environmental Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, South Korea; Graduate School of Energy and Environment (KU-KIST GREEN SCHOOL), Korea University, Seoul, 02841, South Korea.
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