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Journal of Contaminant Hydrology

Charles J Paradis, Ji-Won Moon, Dwayne A Elias, Larry D McKay, Terry C Hazen
Polyfluorinated benzoic acids (PBAs) can be used as non-reactive tracers to characterize reactive mass transport mechanisms in groundwater. The use of PBAs as non-reactive tracers assumes that their reactivities are negligible. If this assumption is not valid, PBAs may not be appropriate to use as non-reactive tracers. In this study, the reactivity of two PBAs, 2,6-difluorobenzoic acid (2,6-DFBA) and pentafluorobenzoic acid (PFBA), was tested in situ. A series of two single-well push-pull tests were conducted in two hydrogeologically similar, yet spatially distinct, groundwater monitoring wells...
September 5, 2018: Journal of Contaminant Hydrology
Esa Puukko, Jukka Lehto, Antero Lindberg, Mikko Voutilainen
This study aims to determine upscaling factors for the radionuclides' distribution coefficients (Kd ) on crushed rocks to intact rock for the safety analysis of radionuclide migration from spent nuclear fuel in bedrock towards biosphere. Here we report the distribution coefficients for intact rock determined by electromigration sorption experiments and compare the results with those from recently performed batch sorption experiments. In total 34 rock samples, representing three typical rock types from Olkiluoto Finland, were studied in order to determine distribution coefficients, effective diffusion coefficients and porosities using the electromigration sorption experiments, formation factor experiments and porosity measurement...
September 2, 2018: Journal of Contaminant Hydrology
Beiyi Xu, Guangcai Wang, Qiang Yang, Yan Zheng
Shallow groundwater in alluvial plains is vulnerable to contamination due to infiltration of pollutants from anthropogenic activities. In the alluvial plain of the Yangtze River near Poyang Lake, a silicone monomer industrial park was found to discharge undisclosed amount of effluents containing high levels of hydrochloric acid and total dissolved solids into ponds and ditches that in turn, displayed characteristics of acidic water with high total dissolved solids. However, most shallow groundwater (n = 35, depth 5...
August 27, 2018: Journal of Contaminant Hydrology
Colin P R McCarter, Tobias K D Weber, Jonathan S Price
There is sparse information on reactive solute transport in peat; yet, with increasing development of peatland dominated landscapes, purposeful and accidental contaminant releases will occur, so it is important to assess their mobility. Previous experiments with peat have only evaluated single-component solutions, such that no information exists on solute transport of potentially competitively adsorbing ions to the peat matrix. Additionally, recent studies suggest chloride (Cl- ) might not be conservative in peat, as assumed by many past peat solute transport studies...
August 13, 2018: Journal of Contaminant Hydrology
P Jamin, S Brouyère
Classic estimates of groundwater fluxes are usually based on the application of Darcy's law, which can lead to large imprecisions in transient groundwater flow cases. There is a need for direct, in situ measurement techniques able to monitor time-variable groundwater fluxes. The investigation presented here demonstrates that the Finite Volume Point Dilution Method (FVPDM) is a promising technique for the continuous monitoring of groundwater fluxes. The experimental configuration consisted of monitoring transient groundwater fluxes generated by a multiple step pumping test, which was undertaken in the alluvial aquifer of the River Meuse, Liège (Belgium)...
July 17, 2018: Journal of Contaminant Hydrology
Jun Zhou, Xiaosi Su, Geng Cui
Groundwater reactive transport models that consider the coupling of hydraulic and biochemical processes are vital tools for predicting the fate of groundwater contaminants and effective groundwater management. The models involve a large number of parameters whose specification greatly affects the model performance. Thus model parameters calibration is crucial to its successful application. The Bayesian inference framework implemented by Markov chain Monte Carlo (MCMC) sampling provides a comprehensive framework to estimate the model parameters...
September 2018: Journal of Contaminant Hydrology
Colin J McNeece, Johannes Lützenkirchen, Marc A Hesse
The effects of acidity and salinity on solute transport in porous media are important to a diverse range of fields from seawater intrusion to nuclear waste storage. Recent transport experiments in quartz sand show the difficulty in capturing the coupling of acidity and salinity under acidic conditions for this system. Here we study the ability of different surface complexation models to capture this coupling, through an analysis of the reactive transport equations in the limit of no diffusion. This chromatographic analysis leads to a graphical representation of the full set of solutions in the phase plane, thus allowing a comprehensive comparison of the transport behavior arising from different SCMs...
September 2018: Journal of Contaminant Hydrology
Naser Shokri, Masoud Montazeri Namin, Javad Farhoudi
A three dimensional coupled numerical model has been developed for incompressible density-driven free surface and saturated porous media flows. For free surface, a time-averaged Navier-Stokes equation has been used whereas Darcy's law has been utilized in porous media flow. The algorithm has been based upon a staggered finite volume scheme on a Cartesian grid that solves the 3D non-hydrostatic density-dependent Darcy equation in one step and complete 3D Navier-Stokes equations in two major steps based on a projection method...
September 2018: Journal of Contaminant Hydrology
Murugan Ramasamy, Christopher Power, Martin Mkandawire
Remediation at former mining sites containing waste rock piles (WRPs) commonly involves the installation of a cover system over the waste rock to limit water and oxygen ingress and attenuate the impacts of acid mine drainage (AMD) to the environment. Cover systems containing high-density polyethylene (HDPE) liners have the attributes to be highly effective; however, their performance over the long-term is unknown. The objective of this study was to assess the long-term effectiveness of an 'in-service' HDPE-lined cover system for reducing AMD contamination at WRP sites...
September 2018: Journal of Contaminant Hydrology
Andrea D'Aniello, Niels Hartog, Thomas Sweijen, Domenico Pianese
Industrial use has led to the presence of liquid elemental mercury (Hg0 ) worldwide in the subsurface as Dense NonAqueous Phase Liquid (DNAPL), resulting in long lasting sources of contamination, which cause harmful effects on human health and detrimental consequences on ecosystems. However, to date, insight into the infiltration behaviour of elemental mercury DNAPL is lacking. In this study, a two-stage flow container experiment of elemental mercury DNAPL infiltration into a variably water saturated stratified sand is described...
September 2018: Journal of Contaminant Hydrology
Zahra Thomas, Benjamin W Abbott
Agricultural contamination of groundwater with nitrate (NO3 - ) is one of the most widespread and pressing environmental issues. The preservation and planting of hedgerows around agricultural fields can reduce NO3 - flux, but the efficacy of hedgerows depends on the amount of NO3 - in soil and groundwater, hydrological flowpath and timing, and biogeochemical conditions surrounding and below roots. Quantifying these parameters is a major challenge, usually requiring involved and destructive fieldwork. Here, we present a new analytical method to characterize NO3 - stratification using water chemistry sampled during piezometer slug tests...
August 2018: Journal of Contaminant Hydrology
Zhuo Jia, Jianmin Bian, Yu Wang
Groundwater is the major available water resources in Harbin City, China, but rapid urbanization has adversely affected it in recent years and groundwater quality is deteriorating. In this study, the groundwater pollution indexes of groundwater monitoring wells were analyzed by using the projection pursuit dynamic clustering model and its spatial distribution was interpolated by using the modified local polynomial interpolation method. The "searchlight" shape model was used to extract the types of land use within the scope of each monitoring well in order to evaluate the relationship between the spatial distribution of groundwater pollution and land use...
August 2018: Journal of Contaminant Hydrology
Khalifa Nsir, Gerhard Schäfer, Raphaël di Chiara Roupert, Lionel Mercury
A numerical simulator based on the discrete network model approach has been developed to simulate drainage processes in a water-saturated porous medium. To verify the predictive potential of the approach to simulate the unstable migration of a dense nonaqueous phase liquid (DNAPL) at the pore scale, the numerical model was applied to laboratory experiments conducted on a sand-filled column. The parameters relative to pore body size and pore throat size used in the construction of the equivalent network were derived from discrete grain-size distribution of the real porous medium...
August 2018: Journal of Contaminant Hydrology
Heather C McLeod, James W Roy, James E Smith
Groundwater contamination from ethanol (e.g., alternative fuels) can support vigorous biodegradation, with many possible reactions producing dissolved gases. The objective of this study was to improve the understanding of the development and evolution of trapped gas phase changes occurring within an ethanol plume undergoing biodegradation. The experiment performed involved highly detailed spatial and temporal monitoring of gas phase saturations using Time Domain Reflectometry probes embedded in a 2-dimensional (175 cm high × 525 cm long) synthetic aquifer (homogeneous sand tank with horizontal groundwater flow)...
August 2018: Journal of Contaminant Hydrology
Ikechukwu A Ike, Mikel Duke
Due to the widespread application of persulphate (PS) for in-situ chemical oxidation (ISCO), the PS activating role of naturally occurring minerals, such as iron oxides, has been the subject of a number of studies. However, major discrepancies remain as to the effectiveness, mode, and factors that influence iron oxides activation of PS. In this study, an attempt has been made to bridge this important knowledge gaps by a systematic study of PS activation, measured by orange G degradation, using commercial and self-synthesised magnetite, maghemite, and haematite particles...
August 2018: 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...
August 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...
August 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...
August 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...
July 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
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