Identification of dominating factors affecting vadose zone vulnerability by a simulation method

Li, Juan; Xi, Beidou; Wutian, Cai; Yang, Yang; Jia, Yongfeng; Li, Xiang; Lv, Yonggao; Lv, Ningqing; Huan, Huan; Yang, Junchang

doi:10.1038/srep45955

Cited by 12 publications

(7 citation statements)

References 39 publications

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“…In agricultural and arable soils, the unsaturated zone provides air, water, and nutrients to plants and soil organisms [1,2]. Hydrologically, the vadose zone controls water and contaminant entry, storage, and movement from the soil surface to the groundwater [3]. Thus, understanding the dynamics of the unsaturated zone is critical for the use and sustainable management of groundwater.…”

Section: Introductionmentioning

confidence: 99%

Impact of Soil Amendments on the Hydraulic Conductivity of Boreal Agricultural Podzols

et al. 2019

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Hydraulic properties of soil are the basis for understanding the flow and transport through the vadose zone. It has been demonstrated that different soil amendments can alter the soil properties affecting soil hydrology. The aim of this study was to determine the effect of soil amendments on hydraulic conductivity (K) of a loamy sand podzolic soil under both unsaturated (Kunsat) and near-saturated (near Ksat) conditions in an agricultural setting. A field experiment was conducted with two common soil amendments: Dairy manure (DM) in 2016 and 2017 and biochar (BC) once only in 2016. DM and BC were incorporated up to a depth of 0.15–0.20 m at a rate of 30,000 L ha−1 and 20 Mg ha−1, respectively. A randomized complete block experimental design was used and the plots planted with silage corn (Zea mays L.) without irrigation. The treatments were: Control without amendment (0N), inorganic N fertilizer (IN), two types of DM (IN+DM1 and IN+DM2), and two treatments with BC (IN+BC and IN+DM1+BC). Infiltration data were collected using a mini disk infiltrometer under three tension levels in which −0.04 and −0.02 m was ascribed as unsaturated (at the wet end) and −0.001 m as near-saturated condition. Based on the measured infiltration rates, Kunsat and near Ksat hydraulic conductivities were calculated. There were no significant effects of DM and BC on bulk density and near Ksat. Treatments IN+DM1, IN+DM2, and IN+DM1+BC significantly reduced the Kunsat compared to the control. Since these soil amendments can influence soil hydrology such as reduced infiltration and increased surface runoff, carefully monitored application of soil amendments is recommended.

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Section: Introductionmentioning

confidence: 99%

Impact of Soil Amendments on the Hydraulic Conductivity of Boreal Agricultural Podzols

et al. 2019

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“…Because of the characteristics of different aquifer types, an understanding of the processes that occur in the vadose zone is fundamental for preserving the groundwater quality [12,13]. Research is therefore needed on how contaminants move through the unsaturated zone before reaching the water table, particularly in close proximity to waste disposal and treatment facilities [14].…”

Section: Introductionmentioning

confidence: 99%

The Geological Characteristics of the Vadose Zone Influence the Impact of Treated Wastewater on the Groundwater Quality (SCA.Re.S. Project 2019–2020)

et al. 2022

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This study evaluated whether some chemical and microbial contaminants in treated sewage effluents from two wastewater treatment plants (WWTP) reached the groundwater when they drained through a fractured karst vadose zone (WWTP-K) and a porous vadose zone (WWTP-P). Forty-five samples of sewage water (SW), treated water (TW), and monitoring well (MW), collected from WWTP-P (24) and WWTP-K (21), were analyzed for a range of microbiological and chemical properties. The E. coli and Salmonella counts were below the limits outlined in the Legislative Decree 152/06 in effluents from both types of WWTP. Enteric viruses were found in 37.5% and 12.5% of the SW and TW from WWTP-P, respectively. The percentages of Pepper mild mottle virus isolated were higher in TW (62.5% in WWTP-P, 85.7% in WWTP-K) than in SW and MW. The residual concentrations of contaminants of emerging concern (CEC) of each drug category were higher in the MW downstream of WWTP-K than of WWTP-P. Our results showed that the porous vadose zone was more effective at reducing the contaminant loads than the fractured karst one, especially the CEC, in the effluent. The legislation should include other parameters to minimize the risks from treated effluent that is discharged to soil.

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“…The numerical modeling of pathways for contaminants in the subsurface in risk assessment frameworks has been attempted in recent studies [24][25][26][27]. An appropriate mathematical model must be selected to simulate the transport, dilution, and reduction of pollutants in the subsurface environment.…”

Section: Introductionmentioning

confidence: 99%

“…An appropriate mathematical model must be selected to simulate the transport, dilution, and reduction of pollutants in the subsurface environment. Complex evaluation processes were conceptualized, and representative (conservative) input parameter values were selected to describe the site characteristics [24,26,27]. Ryu [25] analyzed the behaviors of contaminants such as benzene, toluene, ethylbenzene, and xylenes (BTEX) as well as total petroleum hydrocarbons (TPHs) in the unsaturated zone and modified the behaviors in the conceptualized saturated aquifer implemented by numerical simulation.…”

Section: Introductionmentioning

confidence: 99%

Importance of Infiltration Rates for Fate and Transport of Benzene in High-Tiered Risk-Based Assessment Considering Korean Site-Specific Factors at Contaminated Sites

Chang

Chung

Kim

et al. 2021

Water

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Widely used conservative approaches for risk-based assessments of the subsurface transport processes have been calculated using simple analytical equations or general default values. Higher-tier risk assessment of contaminated sites requires the numerical models or additional site-specific values for input parameters. Previous studies have focused on the development of sophisticated models fit into risk-based frameworks. Our study mainly aims to explore the applicability of site-specific parameters and to modify the risk-based fate and transport model according to the types of the site-specific parameters. To apply the modified fate and transport equation and the site-specific default infiltration range, this study assessed the source depletion, leachate concentrations, and exposure concentration of benzene, which is a representative organic contaminant. The numerical models consist of two continuous processes, the fate and transport of contaminants from (1) the soil to the groundwater table in the vadose zone and subsequently (2) from the groundwater table to exposure wells in the saturated zone. Spatially varied Korean domestic recharge data were successfully incorporated into site-specific infiltration parameters in the models. The numerical simulation results were expressed as transient time series of concentrations over time. Results presented the narrow range of predicted concentrations at the groundwater table when site-specific infiltration was applied, and the dilution–attenuation factors for the unsaturated zone (DAFunsat) were derived based on the prediction. When a contaminant travels to the longest path length of 10 m with a source depth of 1 m in the vadoze zone, the simulated DAFunsat ranged from 3 to 4. The highest DAFunsat simulation results are close to 1 when contaminants travel to a source depth of 5 m and the shortest path length of 1 m. In the saturated aquifer below the contaminated sites, the variation in exposure concentration with time at monitoring wells is detected differently depending on the depth of the saturated zone.

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Identification of dominating factors affecting vadose zone vulnerability by a simulation method

Cited by 12 publications

References 39 publications

Impact of Soil Amendments on the Hydraulic Conductivity of Boreal Agricultural Podzols

Impact of Soil Amendments on the Hydraulic Conductivity of Boreal Agricultural Podzols

The Geological Characteristics of the Vadose Zone Influence the Impact of Treated Wastewater on the Groundwater Quality (SCA.Re.S. Project 2019–2020)

Importance of Infiltration Rates for Fate and Transport of Benzene in High-Tiered Risk-Based Assessment Considering Korean Site-Specific Factors at Contaminated Sites

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