A combined tracer and time-lapse radar imaging experiment was conducted in the unconfined coarse fluvial aquifer at the Boise Hydrogeophysical Research Site in August, 2001. Two tracers (bromide and uranine) were injected to form a plume over a 4-m interval that spanned the contact between hydrostratigraphic units with contrasting permeability. The tracer plume traveled 6.9 m to well B6, passin...

The transport and fate of many contaminants in subsurface systems can be influenced by several coupled processes, such as nonlinear, rate-limited sorption and biodegradation. We investigated the transport in soil of a model organic compound, 2,4-dichlorophenoxyacetic acid (2,4-D), influenced by nonlinear, rate-limited sorption and biodegradation. Miscible displacement and batch sorption experim...

In this study, the adsorption of amoxicillin onto activated carbon was investigated. The effect of particle size and the effluent flow rate was discussed as well as the kinetics and isotherm of adsorption equilibrium. The isotherm equilibrium studies showed that the Langmuir model was appropriate for describing the adsorption equilibrium of amoxicillin onto the activated carbon. Furthermore, th...

Discrete-fracture and dual-porosity models are infrequently used to simulate solute transport through fractured unconsolidated deposits, despite their more common application in fractured rock where distinct flow regimes are hypothesized. In this study, we apply four fracture transport models--the mobile-immobile model (MIM), parallel-plate discrete-fracture model (PDFM), and stochastic and det...

More ecient methods are needed for the in situ evaluation of solute sorption to aquifer sediments. The objective of this study was to develop a simpli®ed method for estimating retardation factors for injected solutes from ``push±pull'' test extraction phase breakthrough curves (BTCs). Sensitivity analyses based on numerical simulations were used to evaluate the method performance for a variety...

[1] We study and explain the origin of early breakthrough and long tailing plume behavior by simulating solute transport through 3-D X-ray images of six different carbonate rock samples, representing geological media with a high degree of pore-scale complexity. A Stokes solver is employed to compute the flow field, and the particles are then transported along streamlines to represent advection,...

[1] This study proposed a new mobile‐immobile model (MIM) to describe reactive solute transport with scale‐dependent dispersion in heterogeneous porous media. The model was derived from the conventional MIM but assumed the dispersivity to be a linear or exponential function of travel distance. The linear adsorption and the first‐order degradation of solute were also considered in the model. The...

Computer models to simulate pesticide transport in the unsaturated zone will be an important management tool in coming years. However, not many efforts were directed to validate the usefulness of such models. In this study, the simulation models GLEAMS, PRZM, and LEACHM were validated. The three models use different mathematical concepts to compute one-dimensional flow and transport in a homoge...