Barometric pressure changes can induce airflow in an open borehole or well screened in the vadose zone, thereby ventilating the soil surrounding the borehole. This paper presents an analytic model of the induced airflow and compares the predictions of the model with experimental measurements. This model may be useful for the design of passive soil vapor extraction as applied to the remediation ...

Long-term dewatering of groundwater is a necessary operation for mining safety in open-pit coal mines, as extensive might cause ecological problems due to dramatic changes moisture movement the soil, especially ecologically fragile areas. In order evaluate impact on vadose zone and vegetation, this paper presents quantitative methodology takes Baorixile mine study example. A long-term situ expe...

The use of treated wastewater for irrigation of crops could result in high nitrate-nitrogen (NO(3)-N) concentrations in the vadose zone and ground water. The goal of this 2-yr field-monitoring study in the deep silty clay loam soils south of Dodge City, Kansas, was to assess how and under what circumstances N from the secondary-treated, wastewater-irrigated corn reached the deep (20-45 m) water...

A 31 year record of ∼44,000 nitrate analyses in ∼11,500 irrigation wells was utilized to depict the decadal expansion of groundwater nitrate contamination (N ≥ 10 mg/L) in the irrigated corn-growing areas of eastern and central Nebraska and analyze long-term nitrate concentration trends in 17 management areas (MAs) subject to N fertilizer and budgeting requirements. The 1.3 M contaminated hecta...

Radionuclide and metal contaminants such as Sr are present beneath U.S. Department of Energy (DOE) lands in both the groundwater (e.g., 100-N area at Hanford, WA) and vadose zone (e.g., Idaho Nuclear Technology and Engineering Center at the Idaho National Engineering and Environmental Laboratory). In situ containment and stabilization of these contaminants is a cost-effective treatment strategy...

Soil nitrate is important for crop growth, but it can also leach to groundwater causing nitrate contamination, a threat to human health. Here, we report a significant accumulation of soil nitrate in Chinese semi-humid croplands based upon more than 7000 samples from 141 sites collected from 1994 to 2015. In the 0-4 meters depth of soil, total nitrate accumulation reaches 453 ± 39, 749 ± 75, 119...

Many non-aqueous phase liquids (NAPLs) are expected to spread at the air-water interface, particularly under non-equilibrium conditions. In the vadose zone, this spreading should increase the surface area for mass transfer and the efficiency of volatile NAPL recovery by soil vapor extraction (SVE). Observations of spreading on water wet surfaces led to a conceptual model of oil spreading vertic...

In developing the Field Investigation Report for the Waste Management Area S-SX at the Hanford Site, Cs was the only gamma emitting radionuclide of concern (Knepp 2002). However, in WMA B-BX-BY, the spectral gamma logging data identify seven gamma emitting radionuclides, Cs, Sb, Eu, Eu, Co, U, and U (DOE-GJPO 1998). The geochemical behaviors of several of these radionuclides, Sb and the two eur...

Methyl tert-butyl ether (MTBE) has been the focus of much attention because it is used in large amounts and was reportedly relatively recalcitrant to bioremediation or natural attenuation. Beginning with a few papers a decade ago, evidence has been presented that, in fact, under suitable conditions it is amenable to bioremediation. Many species from widely disparate microbial genera are able to...

[1] Contaminant migration through the vadose zone may be influenced by the presence of mineral colloids that are mobilized during infiltration events. In this work, we report model calculations and experimental data on the role of pore water ionic strength in the transport of silica colloids through water-saturated and unsaturated porous media. The transport model solves the advection-dispersio...