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Journal of Contaminant Hydrology

Masoud Babaei, Nadim K Copty
The partitioning of surfactants into non-aqueous phase liquids (NAPLs) during Surfactant-Enhanced Aquifer Remediation (SEAR) is potentially an important and non-negligible phenomenon that can strongly impact remediation efficiency. This paper numerically investigates the impact of surfactant partitioning on the enhanced NAPL dissolution and mobilization mechanisms and the overall NAPL removal from the subsurface. For demonstration, a multiphase model is used to simulate a hypothetical SEAR consisting of Triton X100 surfactant solution for the removal of perchloroethylene (PCE) entrapped in contaminated porous medium at the core/column scale...
January 23, 2019: Journal of Contaminant Hydrology
Sean P Funk, Lisa Duffin, Yuhe He, Craig McMullen, Chenxing Sun, Nicholas Utting, Jonathan W Martin, Greg G Goss, Daniel S Alessi
Wastewater recovered from hydraulic fracturing is referred to as flowback and produced water (FPW), and is often saline, contains numerous organic and inorganic constituents, and may pose threats to groundwater resources. Hundreds of spills of FPW have been reported to the Alberta Energy Regulator each year. Recently, samples of FPW derived from hydraulic fracturing of the Duvernay Formation, AB, were found to contain a previously unidentified class of aryl phosphates, including diphenyl phosphate (DPP), triphenyl phosphate (TPP), and others...
January 7, 2019: Journal of Contaminant Hydrology
Mohamad Sakizadeh
The spatial structure and auto-correlation of total dissolved solids (TDS) in an aquifer located in southwestern part of Iran were investigated by both Moran's index and variography. Since the feature of interest was non-stationary so, conventional methods of spatial analysis were not applicable and Universal kriging (UK) as a common method for spatial prediction of features with a spatial trend along with a novel geostatistical method known as fixed rank kriging (FRK) were utilized in this respect. The results of Moran's index were consistent with that of spatial analysis by geostatistical methods indicating the dominance of spatial clusters within the extent of study area...
January 4, 2019: Journal of Contaminant Hydrology
Perrine M Fernandez, Andrew Binley, Esther Bloem, Helen K French
Degradation of organic chemicals in natural soils depends on oxidation-reduction conditions. To protect our groundwater resources we need to understand the degradation processes under anaerobic conditions. Available iron and manganese oxides are used as electron acceptors for anaerobic degradation and are reduced to the dissolved form of metallic cations in pore water. To monitor this process is a challenge, because anaerobic conditions are difficult to sample directly without introducing oxygen. A few studies have shown an impact of iron reduction on spectral induced polarisation (SIP) signature, often associated with bacterial growth...
December 24, 2018: Journal of Contaminant Hydrology
Behrad Gharedaghloo, Jonathan S Price
Extensive pipeline and railway corridors crossing Canadian peatlands make them vulnerable to hydrocarbon spills, potentially impairing ecosystem health, so it is important to be able to forecast hydrocarbon fate and transport within and beyond the peatland. The redistribution of hydrocarbon liquids in groundwater systems are controlled by the multiphase flow characteristics of the aquifer material including capillary pressure-saturation-relative permeability (Pc -S-kr ) relations. However, these relations have never been characterized for the hydrocarbon-water phases in peat...
December 23, 2018: Journal of Contaminant Hydrology
Reza Taherdangkoo, Alexandru Tatomir, Tega Anighoro, Martin Sauter
Hydraulic fracturing in shale/tight gas reservoirs creates fracture network systems that can intersect pre-existing subsurface flow pathways, e.g. fractures, faults or abandoned wells. This way, hydraulic fracturing operations could possibly pose environmental risks to shallow groundwater systems. This paper explores the long-term (> 30 years) flow and transport of fracturing fluids into overburden layers and groundwater aquifers through a leaky abandoned well, using the geological setting of North German Basin as a case study...
December 21, 2018: Journal of Contaminant Hydrology
Janez Perko, Diederik Jacques
Simulation of dissolution processes with a pore-scale reactive transport model increases insight in coupled chemical-physical-transport processes. However, modelling of dissolution process often requires a large number of time steps especially when the buffering capacity of solid phases is high. In this work we analyze the interplay between solid buffering on one hand and transport on the other. Based on this analysis we propose an approach to reduce the number of required time steps for simulating equilibrium dissolution processes...
December 21, 2018: Journal of Contaminant Hydrology
R F Spalding, A J Hirsh, M E Exner, N A Little, K L Kloppenborg
Identification of the nitrate sources that adversely impact groundwater quality is a necessary first step in the control of this major worldwide pollutant. The impact of nitrate leachate from urea-ammonium nitrate (UAN) (50% urea-N, 25% ammonium-N, 25% nitrate-N) fertilizer, whose use has increased dramatically in the last three decades largely because it can be applied through sprinkler irrigation systems to corn in all growth stages, is investigated. The dual isotopes δ15 NNO3 and δ18 ONO3 were measured in groundwater samples from 39 irrigation wells in two intensively sprinkler-irrigated, corn-growing areas of Nebraska with nitrate-contaminated (N > 10 mg/L) groundwater and documented UAN use to ascertain whether nitrified ammonia and nitrate fertilizers can be distinguished in the High Plains aquifer...
December 21, 2018: Journal of Contaminant Hydrology
Paolo Trinchero, Magnus Sidborn, Ignasi Puigdomenech, Urban Svensson, Hedieh Ebrahimi, Jorge Molinero, Björn Gylling, Dirk Bosbach, Guido Deissmann
The rock matrix of granites is expected to be an important buffer against the dispersion of contaminants, e.g. radionuclides, and against the ingress of oxygenated glacial meltwater. The influence of matrix heterogeneity on O2 diffusive transport is assessed here by means of numerical experiments based on a micro-Discrete Fracture Network (micro-DFN) representation of the diffusion-available pore space along with random realisations of idealized biotite grains, to simulate the heterogeneous nature of granitic rocks...
December 7, 2018: Journal of Contaminant Hydrology
Liang Ma, Cheng Huang, Zhong-Sheng Liu, Kevin A Morin, Mike Aziz, Cody Meints
Geochemical reactions taking place at the rock surface and pore water interface, and rapid preferential water flow through waste rock piles are identified as two primary steps for acid rock drainage (ARD) and metal leaching (ML) processes. This paper (Part I) develops a water film model to describe the interactions among sulphide minerals, pore water and oxygen, which considers the reactive surface areas as the primary sites to capture geochemical reactions including sulphide oxidation and neutralization reactions, and also considers acid and metal ion storage in pore water...
December 6, 2018: Journal of Contaminant Hydrology
Velimir V Vesselinov, Boian S Alexandrov, Daniel O'Malley
Unsupervised Machine Learning (ML) is becoming increasingly popular for solving various types of data analytics problems including feature extraction, blind source separation, exploratory analyses, model diagnostics, etc. Here, we have developed a new unsupervised ML method based on Nonnegative Tensor Factorization (NTF) for identification of the original groundwater types (including contaminant sources) present in geochemical mixtures observed in an aquifer. Frequently, groundwater types with different geochemical signatures are related to different background and/or contamination sources...
December 4, 2018: Journal of Contaminant Hydrology
R Hunter Anderson, Dave T Adamson, Hans F Stroo
Metadata from on-going site investigations at U.S. Air Force sites impacted by Aqueous Film-Forming Foam (AFFF) were used to evaluate primary factors that affect transport of poly- and perfluoroalkyl substances (PFAS) within source zones. Soil-to-groundwater ratios (γSoil-GW ) were calculated for each site and PFAS as an empirical transport metric and regressed against select soil chemical and physical properties, as well as relevant interactions thereof, using analysis of covariance (ANCOVA). Total organic carbon and percent total clay content were significant covariates and best fit log-transformed Kd with a parallel lines model...
November 27, 2018: Journal of Contaminant Hydrology
Wei-Hong Dong, Zhipeng Cao, Menglong Li, YuYu Wan, Wei Xie, Chuanlei Wen
In this study, the natural attenuation of naphthalene during riverbank infiltration was examined using batch experiments. The results indicated that, as the grain size and the permeability coefficient decreased, the natural attenuation rate of naphthalene increased, and it was highest in loam (62%) and lowest in coarse sand (20%). The half-life of naphthalene was longest in coarse sand (700 d) and shortest in mild clay (250 d). Facultative anaerobes such as Methylophilaceae accounted for about 70% of the total bacteria and played a major role in naphthalene degradation...
November 23, 2018: Journal of Contaminant Hydrology
M Stoll, F M Huber, M Trumm, F Enzmann, D Meinel, A Wenka, E Schill, T Schäfer
The impact of fracture geometry and aperture distribution on fluid movement and on non-reactive solute transport was investigated experimentally and numerically in single fractures. For this purpose a hydrothermally altered and an unaltered granite drill core with axial fractures were investigated. Using three injection and three extraction locations at top and bottom of the fractured cores, different dipole flow fields were examined. The conservative tracer (Amino-G) breakthrough curves were measured using fluorescence spectroscopy...
November 22, 2018: Journal of Contaminant Hydrology
Pongpun Juntakut, Daniel D Snow, Erin M K Haacker, Chittaranjan Ray
A four-decade dataset (1974-2013) of 107,823 nitrate samples in 25,993 wells from western and eastern parts of Nebraska was used to assess long-term trends of groundwater nitrate concentration and decadal changes in the extent of groundwater nitrate-contaminated areas (NO3 -N ≥ 10 mg N/L) over the entire state. Spatial statistics and regressions were used to investigate the relationships between groundwater nitrate concentrations and several potential natural and anthropogenic factors, including soil drainage capacities, vadose zone characteristics, crop production areas, and irrigation systems...
November 22, 2018: Journal of Contaminant Hydrology
Roger Holten, Frederik Norheim Bøe, Marit Almvik, Sheela Katuwal, Marianne Stenrød, Mats Larsbo, Nicholas Jarvis, Ole Martin Eklo
Limited knowledge and experimental data exist on pesticide leaching through partially frozen soil. The objective of this study was to better understand the complex processes of freezing and thawing and the effects these processes have on water flow and pesticide transport through soil. To achieve this we conducted a soil column irrigation experiment to quantify the transport of a non-reactive tracer and the herbicide MCPA in partially frozen soil. In total 40 intact topsoil and subsoil columns from two agricultural fields with contrasting soil types (silt and loam) in South-East Norway were used in this experiment...
December 2018: Journal of Contaminant Hydrology
Stephane K Ngueleu, Fereidoun Rezanezhad, Riyadh I Al-Raoush, Philippe Van Cappellen
Considerable activities from the oil and natural gas sector have risen some concerns about the pollution of soil and groundwater by petroleum hydrocarbons (PHCs) in (semi)-arid coastal regions. The understanding of the fate and transport of PHCs in these regions is therefore necessary to develop strategies for remediation. To quantify the sorption rates of PHCs in (semi)-arid coastal soil environments, we conducted a series of controlled-laboratory batch experiments under variable temperature and salinity conditions...
December 2018: Journal of Contaminant Hydrology
N Sihota, B McAlexander, M Lyverse, K U Mayer
The changing landscape of fuel consumption related, in part, to increased engine efficiency and the inexpensive supply of natural gas, has led to the closure of multiple refineries. As the operational lifetime of many refineries exceeds 100 years, historical releases of oil and refined products is common. To evaluate remediation and rehabilitation options, there is a need to understand the rate and distribution of natural hydrocarbon mass losses across these large properties. Here, surficial CO2 flux measurements were used to evaluate naturally occurring hydrocarbon mass losses at a large-scale former refinery that has been closed since 1982...
December 2018: Journal of Contaminant Hydrology
Brianne N Hicknell, Kevin G Mumford, Bernard H Kueper
In situ thermal treatment (ISTT) technologies have been applied at sites impacted by non-aqueous phase liquids (NAPLs). There is a need to establish expectations for the treatment of semi-volatile NAPLs, including those consisting primarily of polycyclic aromatic hydrocarbons (PAHs), and the potential benefits and limitations of partial NAPL removal. A series of laboratory experiments was conducted to investigate NAPL removal and soil concentrations during the heating of creosote-impacted sand, as well as aqueous concentrations during post-heating dissolution...
December 2018: Journal of Contaminant Hydrology
Michael C Brooks, A Lynn Wood, Jaehyun Cho, Christine A P Williams, William Brandon, Michael D Annable
Source strength functions (SSF), defined as contaminant mass discharge or flux-averaged concentration from dense nonaqueous phase liquid (DNAPL) source zones as a function of time, provide a quantitative model of DNAPL source-zone behavior. Such information is useful for calibration of screening-level models to assist with site management decisions. We investigate the use of historic data collected during long-term monitoring (LTM) activities at a site in Rhode Island to predict the SSF based on temporal mass discharge measurements at a fixed location, as well as SSF estimation using mass discharge measurements at a fixed time from three spatially distributed control planes...
December 2018: Journal of Contaminant Hydrology
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