Showing papers in "Journal of Contaminant Hydrology in 2014"

TL;DR: A variable-index fractional-derivative model (FDM) is proposed to describe the underlying transport dynamics of contaminant plumes and can efficiently quantify these transitions, with the scale index varying linearly in time or space.

TL;DR: The fate and behavior of a range of organic compounds during RBF were investigated using a two dimensional numerical flow- and transport model and breakthrough curves of clindamycin, phenazone, diclofenac and sulfamethoxazole could be fitted less well, probably due to the dependency of degradation on temperature and redox conditions, which are highly transient at the RBF site.

TL;DR: This study determined the extent and mechanisms of U release from a heterogeneous natural sediment under water chemistry conditions relevant to natural soil water and groundwater, and found that U release is controlled by a number of interactive processes including dissolution of U-bearing minerals, U desorption from mineral surface, formation of aqueous U complexes, and reductive precipitation of U.

TL;DR: This study examined the colloid adsorption behavior of four different sizes of carboxylate-modified latex (CML) microspheres, as surrogates for viruses and bacteria, in batch and column experiments over a wide range of solution ionic strengths (IS).

TL;DR: A compilation of colloid-borne forms of tetravalent actinides described so far for laboratory experiments together with several examples of An(IV) colloids observed in field experiments and real-world scenarios are given to be a knowledge base and a tool for those who have to interpret actinide behavior under environmental conditions.

TL;DR: The main contributors to the removal of organic/inorganic contaminants were ZVI and AC, and the optimum weight ratio of the three PRB materials for removing the contaminants and maintaining adequate hydraulic conductivity was found to be 5:1:4.

TL;DR: Overall, this study highlights that the transport and especially retention of PVP-AgNPs are highly sensitive to the physicochemical factors, but mathematical modeling can accurately predict the fate of these ENPs in porous media which is important for better understanding the fate in point of exit and in the environment.

TL;DR: A numerical study was undertaken to investigate the effects of waves on groundwater flow and associated inland-released solute transport based on tracer experiments in a laboratory beach and revealed that waves generated seawater-groundwater circulations in the swash and surf zones of the beach, which induced a large seawater -groundwater exchange across the beach face.

TL;DR: The combined effects of mineral colloids and HA on contaminant transport is different from simple addition of the individual effect, and it is demonstrated that U transport is enhanced due to enhanced U adsorption to illite colloids via formation of ternary illite-HA-U surface complexes.

TL;DR: The obtained results show that mZVI slurries stabilized by guar gum can be prepared at pilot scale and directly injected into low permeable aquifers, indicating a significant removal of 1,1,1-TCA.

TL;DR: This study presents an in situ experiment designed for estimating heat transfer parameters in shallow alluvial aquifers with focus on the specific heat capacity and highlights that heat transfer in the alluvIAL aquifer of the Meuse River is complex and contrasted with different dominant process depending on the depth leading to significant vertical heat exchange between upper and lower part of the aquifer.

TL;DR: Streamflow generation in a small pre-Alpine headwater catchment was analyzed over a 2-year period by means of rainfall-response analysis and water quality data under explicit consideration of the joint behaviors of climate forcing and shallow groundwater dynamics, suggesting a more continuous shift from a riparian-zone to a more hillslope-dominated streamflow hydrograph.

TL;DR: 4D time-lapse ERT has potential for mapping where and how quickly DNAPL mass changes in real time during site remediation, and can provide a reasonable estimate of theDNAPL volume remediated with time.

TL;DR: The simulation results indicated that several concurrent aspects are to be taken into account for the design of a successful delivery of MZVI/guar gum slurries via permeation injection, and a compromise is necessary between maximizing the radius of influence of the injection and minimizing the injection pressure.

TL;DR: Identification and elucidation of cluster-specific contamination mechanisms may be used to develop improved overall risk management and wellhead protection strategies, while also informing future remediation and maintenance efforts.

TL;DR: GB pressure is a more accurate indicator of partial sample saturation than swelling pressure Pswell alone, which has to be minimal for sealing radioactive waste repositories.

TL;DR: The results show that oil constituents other than BTEX, including n-alkanes and other aromatic compounds, play significant roles in plume evolution and secondary water quality impacts, and underscores the importance of non-aqueous phases.

TL;DR: The multi-step approach aiming at source identification and release history estimation has proven to be effective and may be applied to other complicated contamination cases and the capability of the geostatistical approach to manage a complex real case study is shown.

TL;DR: The results indicate generally low levels of organic micropollutants in the stormwater, as the contaminants detected were present at very low ng/L levels, generally two to four orders of magnitude below the drinking water guidelines (NHMRC, 2011).

TL;DR: Leaching behavior of neonicotinoid insecticides based on the leachability indices such as groundwater ubiquity score, relative leaching potential, and partitioning between different environmental matrices through a fugacity-based equilibrium criterion model clearly indicates that DNT may pose a greater threat to aquatic resources compared to IMD and THM.

TL;DR: Results from 2-dimensional modelling of the river-floodplain hydrological processes were consistent with field measurements during the drying phase and illustrated how the declining river levels led to floodplain acidification.

TL;DR: Historical groundwater-withdrawal and contaminant-concentration data collected from long-term pump-and-treat operations were analyzed and used to examine contaminant mass discharge (CMD) and mass-removal behavior for multiple sites, illustrating that detailed analysis of operational pump- and-t treat data can be a cost-effective method for providing value-added characterization of contaminated sites.

TL;DR: Simulation results demonstrate the impact of heterogeneous distribution of geochemical reactive surface area in coordination with physical heterogeneity on the effective reaction rate (Krxn,eff) and Pb(2+) concentrations within the plume.

TL;DR: The results indicate the potential discharge zone of the plume to extend along a stream reach of 120 m in length, delineated by a network of 60 in-situ diffusion samplers, and detections of cis-1,2-dichloroethene and vinyl chloride in discrete sections of the sediment profile indicate that shallow TCE transformation may be significant at a local scale in the streambed deposits.

TL;DR: Numerical flow and particle transport modeling is used to provide insight into the origin of samples under ambient vertical head gradients and under a range of pumping rates in wells driven by ambient verticalHead gradients.

TL;DR: This work demonstrates that stimulating in situ denitrification in an aerobic, highly conductive aquifer is challenging but achievable, and further work is needed to increase rates of denitrified bacteria in the most permeable units of the aquifer.

TL;DR: The performance of LDRM on predicting the distribution and recovery of LNAP was reasonably accurate for a short-term analysis as demonstrated in a case study, but further validation is needed to ascertain the model's performance in long-term simulations.

TL;DR: The results demonstrate the restricted applicability of AgNP transport parameters determined from simplified experimental model systems to realistic environmental matrices.

TL;DR: The results of this study demonstrate that laboratory-based experiments may be able to mimic flow regimes observed in the field; however, the requirement of scale-dependent dispersivities and mass-transfer coefficients indicates that these tests may be more limited in understanding larger-scale solute transport between regions of different mobility.

TL;DR: Transport properties of activated carbon colloid supported nZVI are investigated and results suggest potential applicability of c-nZVI under field conditions.