The stable isotopes deuterium (H, D) and oxygen 18 (O) were applied in water for use as tracers in column experiments and in two field studies. Their performance was compared against uranine and was used to characterize saturated and unsaturated water movement and depths of plant water uptake. Deuterium and O are completely soluble and chemically and biologically stable. They are not subject to...

The invasive Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae) has been evident in the North Carolina Piedmont, United States for 90 yr but has failed to spread further north. We investigated the mechanisms preventing this expansion. The Argentine ant ceases foraging at temperatures below 5°C and we hypothesized that winter soil temperatures at higher latitudes restricted fora...

[1] The sensitivity of a global land-surface model projection of near-surface permafrost degradation is assessed with respect to explicit accounting of the thermal and hydrologic properties of soil organic matter and to a deepening of the soil column from 3.5 to 50 or more m. Together these modifications result in substantial improvements in the simulation of near-surface soil temperature in th...

The bioremediation of 2,4,6-trinitrotoluene (TNT) contaminated soil was performed on a laboratory scale. To compare bioremediation methods, a soil slurry reactor and a soil column reactor were operated and the effects of supplemental sources were investigated. Optimal conditions for the two bioremediation systems for the removal of TNT were obtained. In the soil slurry reactor, about 60% of the...

Colloidal gas aphron dispersions (CGAs) can be described as a system of microbubbles suspended homogenously in a liquid matrix. This work examines the performance of CGAs in comparison to surfactant solutions for washing low levels of arsenic from an iron rich soil. Sodium Dodecyl Sulfate (SDS) and saponin, a biodegradable surfactant, obtained from Sapindus mukorossi or soapnut fruit were used ...

The mobility of clomazone [2-(2-chlorobenzylo)-4,4-dimetylo-1,2-oxazolidin-3-one] in a loamy sand soil and a sand soil was studied in a soil column under laboratory conditions. Commercial clomazone formulation (Command 480 EC) and clomazone immobilized in an alginate matrix were used for a leaching experiment. For both formulations, the same dose of 2.0 mg of the active substance was applied. A...

Magne c resonance imaging (MRI) was applied to the study of fl ow processes in model and natural soil cores. Flow veloci es in soils are mostly too slow to be monitored directly by MRI fl ow velocity imaging. Therefore, we used for the fi rst me diethylenetriaminepentaacetate in the form Gd-DTPA2− as a tracer in spin echo mul slice imaging protocols with strong weigh ng of longitudinal relaxa o...

This study presents the experimental remediation studies of diesel contaminated soil with Sodium Deducible Sulfate (SDS) as surfactants using column tests. Sandy selected soil had the grain size distribution of # 40 meshes to the # 200 mesh range. The soil columns were contaminated with adequate diesel amount to achieve the concentration of 10000 and 20000 ppm in soil. 0.1, 0.2, 0.3, 0.4 percen...