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Journal of Contaminant Hydrology

Joanna Doummar, Michel Aoun
The assessment of vulnerability in karst systems reveals to be extremely challenging since it varies significantly with time and highly depends on the identification of diffuse and concentrated infiltration from surface karst features. The origin, consumed loads, and transport mode of selected micropollutants (MPs) including two artificial sweeteners (ASWs) Sucralose (SUC) and Acesulfame-K (ACE-K), in addition to other less investigated pharmaceuticals such as the lipid regulator Gemfibrozil (GEM), and the contrast media Iohexol (IOX) were investigated in a karst system under dynamic conditions...
July 5, 2018: Journal of Contaminant Hydrology
Costantino Masciopinto, Giuseppe Passarella
The theory for modeling non-equilibrium solute transport in porous media is still based on approximations to a model proposed by Lapidus and Amundson in 1952 that has not been updated. This Mobile-Immobile Model (MIM) is based on the definition of a mass-transfer coefficient (α), which has been proven subject to some severe limitations. Measurements at both laboratory and field scales have demonstrated the scale-dependency of α values. This means that the MIM theory fails in real applications, since α is not constant, as defined in the kinetic model theory, but is a time-residence (or distance) dependent coefficient...
June 30, 2018: Journal of Contaminant Hydrology
Yawen Chang, Bill X Hu, Zexuan Xu, Xue Li, Juxiu Tong, Lin Chen, Hanxiong Zhang, Jinjie Miao, Hongwei Liu, Zhen Ma
Seawater intrusion and brine water/freshwater interaction have significantly affected agriculture, industry and public water supply at Laizhou Bay, Shandong Province, China. In this study, a two-dimensional SEAWAT model is developed to simulate the seawater intrusion to coastal aquifers and brine water/fresh water interaction in the south of Laizhou Bay. This model is applied to predict the seawater intrusion and brine water/freshwater interface development in the coming years. The model profile is perpendicular to the coastal line with two interfaces, freshwater-saline water interface near the shore and inland brine water-saline water-seawater interface...
June 18, 2018: Journal of Contaminant Hydrology
Qianqian Zhang, Huiwei Wang, Long Wang
Nitrate contamination in groundwater has become an environmental problem of widespread concern. In this study, we used environmental isotopes (δ15 N-NO3 - and δ18 O-NO3 - ) and an isotope mixing model (SIAR) to identify the main sources of nitrate pollution, and factors controlling nitrate pollution, and to quantify the relative contributions of potential NO3 - sources in an over-exploited groundwater region, north China. The results showed that human activities had dramatically increased the mean concentration of groundwater NO3 - reaching 124...
June 15, 2018: Journal of Contaminant Hydrology
Carlos H Maldaner, Patrick M Quinn, John A Cherry, Beth L Parker
A straddle-packer system for use in boreholes in fractured rock was modified to investigate the average linear groundwater velocity (v¯f ) in fractures under ambient flow conditions. This packer system allows two different tests to be conducted in the same interval between packers without redeploying the system: (1) forced gradient hydraulic tests to determine the interval transmissivity (T), and (2) borehole dilution experiments to determine the groundwater flow rate (Qt ) across the test interval. The constant head step test method provides assurance that flow is Darcian when determining T for each interval and identifies the flow rate at the onset of non-Darcian flow...
May 17, 2018: Journal of Contaminant Hydrology
S Blackmore, D Pedretti, K U Mayer, L Smith, R D Beckie
Accurate predictions of solute release from waste-rock piles (WRPs) are paramount for decision making in mining-related environmental processes. Tracers provide information that can be used to estimate effective transport parameters and understand mechanisms controlling the hydraulic and geochemical behavior of WRPs. It is shown that internal tracers (i.e. initially present) together with external (i.e. applied) tracers provide complementary and quantitative information to identify transport mechanisms. The analysis focuses on two experimental WRPs, Piles 4 and Pile 5 at the Antamina Mine site (Peru), where both an internal chloride tracer and externally applied bromide tracer were monitored in discharge over three years...
July 2018: Journal of Contaminant Hydrology
Sohaib Aslam, Akhtar Iqbal, François Lafolie, Sylvie Recous, Pierre Benoit, Patricia Garnier
Crop residues left on the soil surface as mulch greatly influence the fate of pesticides in conservation agricultural practices because most of the applied pesticide is intercepted by mulch before passing to the soil. Modelling of pesticide losses from wash-off and leaching will greatly improve our understanding of the environmental consequences of pesticides in these systems. The PASTIS model, which simulates water transfer, mulch decomposition, and pesticide dynamics, was adapted in this new version to model the interactions between pesticides and mulch in order to simulate the impact of mulch on pesticide dynamic...
July 2018: Journal of Contaminant Hydrology
Thomas Pabst, Bruno Bussière, Michel Aubertin, John Molson
The generation of acid mine drainage (AMD) remains a major environmental challenge for the mining industry. The reclamation of old mine sites with pre-oxidized tailings is particularly challenging because of indirect oxidation reactions which can limit the overall effectiveness of an oxygen barrier to prevent AMD. The goal of this project was to quantitatively compare the effectiveness of different cover systems to reclaim two pre-oxidized acid-generating tailings sites, located in Quebec (Canada). Following laboratory column tests, field measurements and observations, coupled hydrogeological and geochemical numerical simulations were conducted to evaluate the effect of various system characteristics...
July 2018: Journal of Contaminant Hydrology
Quentin Giraud, Julio Gonçalvès, Benoît Paris, Antoine Joubert, Stéfan Colombano, David Cazaux
Remediation of dense non-aqueous phase liquids (DNAPLs) represents a challenging issue because of their persistent behaviour in the environment. This pilot-scale study investigates, by means of in situ experiments and numerical modelling, the feasibility of the pulsed pumping process of a large amount of a DNAPL in an alluvial aquifer. The main compound of the DNAPL is hexachlorobutadiene (HCBD), added in 2015 to the persistent organic pollutants list (POP). A low-permeability keyed enclosure was built at the location of the DNAPL source zone in order to isolate a finite volume of soil and a 3-month pulsed pumping process was applied inside the enclosure to exclusively extract the DNAPL...
July 2018: Journal of Contaminant Hydrology
Clément Portois, Elyess Essouayed, Michael D Annable, Nathalie Guiserix, Antoine Joubert, Olivier Atteia
A novel approach using foam to manage hazardous waste was successfully demonstrated under active site conditions. The purpose of the foam was to divert groundwater flow, that would normally enter the source zone area, to reduce dissolved contaminant release to the aquifer. During the demonstration, foam was pre generated and directly injected surrounding the chlorinated solvent source zone. Despite the constraints related to the industrial activities and non-optimal position of the injection points, the applicability and effectiveness of the approach have been highlighted using multiple metrics...
July 2018: Journal of Contaminant Hydrology
Julien Farlin, Tom Gallé, Michael Bayerle, Denis Pittois, Stephan Köppchen, Martina Krause, Diana Hofmann
We present the results of a two years study on the contamination of the Luxembourg Sandstone aquifer by metolachlor-ESA and metolachlor-OXA, two major transformation products of s-metolachlor. The aim of the study was twofold: (i) assess whether elevated concentrations of both transformation products (up to 1000 ng/l) were due to fast flow breakthough events of short duration or the signs of a contamination of the entire aquifer and (ii) estimate the time to trend reversal once the parent compound was withdrawn from the market...
June 2018: Journal of Contaminant Hydrology
Cornelia Wigger, Luc R Van Loon
The effect of the pore water composition on the diffusive anion transport was studied for two different argillaceous, low permeability sedimentary rocks, Opalinus Clay (OPA) and Helvetic Marl (HM). The samples were saturated with different solutions with varying molar concentration and different main cations in the solution: NaCl based pore solutions and CaCl2 based pore solutions. The total porosity was measured by through-diffusion experiments with the neutral tracer HTO. Experiments performed in NaCl solutions resulted in a porosity of 0...
June 2018: Journal of Contaminant Hydrology
Saeid Shafieiyoun, Neil R Thomson
An experimental and computational study was performed to investigate the role of multi-component intra-NAPL diffusion on NAPL-water mass transfer. Molecular weight and the NAPL component concentrations were determined to be the most important parameters affecting intra-NAPL diffusion coefficients. Four NAPLs with different viscosities but the same quantified mass were simulated. For a spherical NAPL body, a combination of NAPL properties and interphase mass transfer rate can result in internal diffusion limitations...
June 2018: Journal of Contaminant Hydrology
Martin A Dangelmayr, Paul W Reimus, Raymond H Johnson, James T Clay, James J Stone
This research assesses the ability of a GC SCM to simulate uranium transport under variable geochemical conditions typically encountered at uranium in-situ recovery (ISR) sites. Sediment was taken from a monitoring well at the SRH site at depths 192 and 193 m below ground and characterized by XRD, XRF, TOC, and BET. Duplicate column studies on the different sediment depths, were flushed with synthesized restoration waters at two different alkalinities (160 mg/l CaCO3 and 360 mg/l CaCO3 ) to study the effect of alkalinity on uranium mobility...
June 2018: Journal of Contaminant Hydrology
Kenton Rod, Wooyong Um, Jaehun Chun, Ning Wu, Xialong Yin, Guohui Wang, Keith Neeves
A set of column experiments was conducted to investigate the chemical and physical heterogeneity effect on colloid facilitated transport under slow pore velocity conditions. Pore velocities were kept below 100 cm d-1 for all experiments. Glass beads were packed into columns establishing four different conditions: 1) homogeneous, 2) mixed physical heterogeneity, 3) sequentially layered physical heterogeneity, and 4) chemical heterogeneity. The homogeneous column was packed with glass beads (diameter 500-600 μm), and physical heterogeneities were created by sequential layering or mixing two sizes of glass bead (500-600 μm and 300-400 μm)...
June 2018: Journal of Contaminant Hydrology
Kewei Chen, Hongbin Zhan
The reactive solute transport in a single fracture bounded by upper and lower matrixes is a classical problem that captures the dominant factors affecting transport behavior beyond pore scale. A parallel fracture-matrix system which considers the interaction among multiple paralleled fractures is an extension to a single fracture-matrix system. The existing analytical or semi-analytical solution for solute transport in a parallel fracture-matrix simplifies the problem to various degrees, such as neglecting the transverse dispersion in the fracture and/or the longitudinal diffusion in the matrix...
June 2018: Journal of Contaminant Hydrology
Sandip S Sathe, Chandan Mahanta, Pushpanjali Mishra
In the dynamic cycling of oxic and anoxic aqueous alluvial aquifer environments, varying Arsenic (As) concentrations are controlled by both abiotic and biotic factors. Studies have shown a significant form of toxic As (III) being released through the reductive dissolution of iron-oxy/hydroxide minerals and microbial reduction mechanisms, which leads to a serious health concern. The present study was performed in order to assess the abiotic and biotic factors influencing As release into the alluvial aquifer groundwater in Brahmaputra floodplain, India...
June 2018: Journal of Contaminant Hydrology
Branko Bijeljic, Matteo Icardi, Maša Prodanović
No abstract text is available yet for this article.
May 2018: Journal of Contaminant Hydrology
Amanda A Pierce, Steven W Chapman, Laura K Zimmerman, Jennifer C Hurley, Ramon Aravena, John A Cherry, Beth L Parker
Plumes of trichloroethene (TCE) with degradation products occur at a large industrial site in California where TCE as a dense non-aqueous phase liquid (DNAPL) entered the fractured sandstone bedrock at many locations beginning in the late 1940s. Groundwater flows rapidly in closely spaced fractures but plume fronts are strongly retarded relative to groundwater flow velocities owing largely to matrix diffusion in early decades and degradation processes in later decades and going forward. Multiple data types show field evidence for both biotic and abiotic dechlorination of TCE and its degradation products, resulting in non-chlorinated compounds...
May 2018: Journal of Contaminant Hydrology
Rahul Verma, Matteo Icardi, Maša Prodanović
Understanding of pore-scale physics for multiphase flow in porous media is essential for accurate description of various flow phenomena. In particular, capillarity and wettability strongly influence capillary pressure-saturation and relative permeability relationships. Wettability is quantified by the contact angle of the fluid-fluid interface at the pore walls. In this work we focus on the non-trivial interface equilibria in presence of non-neutral wetting and complex geometries. We quantify the accuracy of a volume-of-fluid (VOF) formulation, implemented in a popular open-source computational fluid dynamics code, compared with a new formulation of a level set (LS) method, specifically developed for quasi-static capillarity-dominated displacement...
May 2018: Journal of Contaminant Hydrology
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