A critical review of the influence of groundwater level fluctuations and temperature on LNAPL contaminations in the context of climate change

Cavelan, Amélie; Golfier, Fabrice; Colombano, Stéfan; Davarzani, Hossein; Deparis, Jacques; Faure, Pierre

doi:10.1016/j.scitotenv.2021.150412

Cited by 43 publications

(25 citation statements)

References 141 publications

(233 reference statements)

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“…The process of petroleum pollutant migration includes convection, diffusion, dispersion, dissolution, volatilization, adsorption, and desorption. Along with groundwater level uctuations, different pollutant components are continuously exchanged, migrated, adsorbed, desorbed, and diffused in the unsaturated zone, groundwater uctuation zone, and aquifer (Amélie et al, 2021;Yuhong et al, 2022). LNAPL moves downward vertically in the aeration zone, gradually replacing capillary water.…”

Section: Introductionmentioning

confidence: 99%

WITHDRAWN: Effect of unsaturated flow on the occurrence and movement of light nonaqueous phase fluids

Zhao,

Cheng,

et al. 2023

Preprint

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Contamination from light nonaqueous phase fluids (LNAPL) and their derivatives during mining, production, and transportation has become a concern. Scholars have extensively studied LNAPL contamination, but the role of water content variation on its migration process in the unsaturated zone has not been sufficiently researched. In this study, indoor simulated vertical, one-dimensional, multiphase flow soil column experiments were conducted on the sandy soil of the Zhengzhou reach of the Yellow River to analyze the effect of water content on the occurrence state and migration rate of LNAPL. The experimental results indicate: (1) The migration rate of LNAPL exhibits an L-shaped trend during subsurface imbibition and a nonlinear relationship with migration time, and the migration rate and migration time of surface infiltration have a linear growth relationship. (2) The adsorption rate of LNAPL is negatively correlated with water content and positively correlated with oil content in the homogeneous non-saturated state. As LNAPL moves from the aeration zone to the saturated zone, the relationship between oil content and water content is nonlinear. (3) When the water content of the test medium is below 14% and the oil content is below 11%, LNAPL appears in the aeration zone in a solid phase. As the water content increases, the adsorption rate of the oil phase gradually decreases and eventually reaches the oil saturation point. (4) When the water content of the medium exceeds 8%, over time, LNAPL will be subject to oil-water interfacial tension, and the rate of LNAPL movement first decreases and then increases, displaying nonlinear growth.

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Section: Introductionmentioning

confidence: 99%

WITHDRAWN: Effect of unsaturated flow on the occurrence and movement of light nonaqueous phase fluids

Zhao,

Cheng,

et al. 2023

Preprint

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“…Complete hydrolysis is possible in the range of 173–200°C, while at lower temperatures, the hydrolysis rate is rather slow ( Cristina et al, 2018 ). Groundwater temperatures are apparently not that high ( Cavelan et al, 2022 ). This also ensures the smooth operation of the LBM.…”

Section: Resultsmentioning

confidence: 99%

Bioenhanced degradation of toluene by layer-by-layer self-assembled silica-based bio-microcapsules

Lin

Yang²,

Li³

et al. 2023

Front. Microbiol.

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In this study, micron-sized monodisperse SiO2 microspheres were used as sacrificial templates, and chitosan/polylactic acid (CTS/PLA) bio-microcapsules were produced using the layer-by-layer (LBL) assembly method. Microcapsules isolate bacteria from their surroundings, forming a separate microenvironment and greatly improving microorganisms’ ability to adapt to adverse environmental conditions. Morphology observation indicated that the pie-shaped bio-microcapsules with a certain thickness could be successfully prepared through LBL assembly method. Surface analysis showed that the LBL bio-microcapsules (LBMs) had large fractions of mesoporous. The biodegradation experiments of toluene and the determination of toluene degrading enzyme activity were also carried out under external adverse environmental conditions (i.e., unsuitable initial concentrations of toluene, pH, temperature, and salinity). The results showed that the removal rate of toluene by LBMs can basically reach more than 90% in 2 days under adverse environmental conditions, which is significantly higher than that of free bacteria. In particular, the removal rate of toluene by LBMs can reach four times that of free bacteria at pH 3, which indicates that LBMs maintain a high level of operational stability for toluene degradation. Flow cytometry analysis showed that LBL microcapsules could effectively reduce the death rate of the bacteria. The results of the enzyme activity assay showed that the enzyme activity was significantly stronger in the LBMs system than in the free bacteria system under the same unfavorable external environmental conditions. In conclusion, the LBMs were more adaptable to the uncertain external environment, which provided a feasible bioremediation strategy for the treatment of organic contaminants in actual groundwater.

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“…A sharp increase in concentrations was also found by Rahim et al [ 6 ], which is related to the rain intensity. The high rain intensity elevated the groundwater table, which would then bring 1,1-DCE back to the groundwater from soil or sand [ 25 , 26 , 27 ].…”

Section: Resultsmentioning

confidence: 99%

Prediction of Dichloroethene Concentration in the Groundwater of a Contaminated Site Using XGBoost and LSTM

Xia

Jiang

Kong

et al. 2022

IJERPH

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Chlorinated aliphatic hydrocarbons (CAHs) are widely used in agriculture and industries and have become one of the most common groundwater contaminations. With the excellent performance of the deep learning method in predicting, LSTM and XGBoost were used to forecast dichloroethene (DCE) concentrations in a pesticide-contaminated site undergoing natural attenuation. The input variables included BTEX, vinyl chloride (VC), and five water quality indicators. In this study, the predictive performances of long short-term memory (LSTM) and extreme gradient boosting (XGBoost) were compared, and the influences of variables on models’ performances were evaluated. The results indicated XGBoost was more likely to capture DCE variation and was robust in high values, while the LSTM model presented better accuracy for all wells. The well with higher DCE concentrations would lower the model’s accuracy, and its influence was more evident in XGBoost than LSTM. The explanation of the SHapley Additive exPlanations (SHAP) value of each variable indicated high consistency with the rules of biodegradation in the real environment. LSTM and XGBoost could predict DCE concentrations through only using water quality variables, and LSTM performed better than XGBoost.

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A critical review of the influence of groundwater level fluctuations and temperature on LNAPL contaminations in the context of climate change

Cited by 43 publications

References 141 publications

WITHDRAWN: Effect of unsaturated flow on the occurrence and movement of light nonaqueous phase fluids

WITHDRAWN: Effect of unsaturated flow on the occurrence and movement of light nonaqueous phase fluids

Bioenhanced degradation of toluene by layer-by-layer self-assembled silica-based bio-microcapsules

Prediction of Dichloroethene Concentration in the Groundwater of a Contaminated Site Using XGBoost and LSTM

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