Ground Water 

About: Ground Water is an academic journal published by Wiley-Blackwell. The journal publishes majorly in the area(s): Aquifer & Groundwater. It has an ISSN identifier of 0017-467X. Over the lifetime, 5351 publications have been published receiving 148940 citations. The journal is also known as: GW & Groundwater.

Enhanced Degradation of Halogenated Aliphatics by Zero‐Valent Iron

Abstract: Laboratory tests were conducted to examine zero-valent iron as an enhancing agent in the dehalogenation of 14 chlorinated methanes, ethanes, and ethenes. All compounds were tested by batch procedures in which 10 g of 100-mesh electrolytic iron was added to 40 ml hypovials. Aqueous solutions of the respective compounds were added to the hypovials, and the decline in concentration was monitored over time. Substantial rates of degradation were observed for all compounds tested with the exception of dichloromethane. The degradation process appeared to be pseudo first-order with respect to the organic compound, with the rate constant appearing to be directly proportional to the surface area to volume ratio and increasing with increasing degree of chlorination. Column tests showed the process to proceed under flow conditions with degradation rates indpendent of velocity and consistent with those measured in the batch tests. When normalized to 1 m2/ml, the t50 values ranged from 0.013 to 20 hr, and were about 5 to 15 orders of magnitude lower than values reported for natural rates of abiotic degradation. The results indicate abiotic reductive dechlorination, with iron serving as the source of electrons; the mechanism is, however, uncertain. Based on the rapid rates of degradation, both in situ and aboveground applications for remediation of contaminated ground water are proposed.

Heat as a ground water tracer.

Abstract: Heat carried by ground water serves as a tracer to identify surface water infiltration, flow through fractures, and flow patterns in ground water basins. Temperature measurements can be analyzed for recharge and discharge rates, the effects of surface warming, interchange with surface water, hydraulic conductivity of streambed sediments, and basin-scale permeability. Temperature data are also used in formal solutions of the inverse problem to estimate ground water flow and hydraulic conductivity. The fundamentals of using heat as a ground water tracer were published in the 1960s, but recent work has significantly expanded the application to a variety of hydrogeological settings. In recent work, temperature is used to delineate flows in the hyporheic zone, estimate submarine ground water discharge and depth to the salt-water interface, and in parameter estimation with coupled ground water and heat-flow models. While short reviews of selected work on heat as a ground water tracer can be found in a number of research papers, there is no critical synthesis of the larger body of work found in the hydrogeological literature. The purpose of this review paper is to fill that void and to show that ground water temperature data and associated analytical tools are currently underused and have not yet realized their full potential.

Arsenic in Ground Water of the United States: Occurrence and Geochemistry

Abstract: Concentrations of naturally occurring arsenic in ground water vary regionally due to a combination of climate and geology Although slightly less than half of 30,000 arsenic analyses of ground water in the United States were 1 μg/L, about 10% exceeded 10 μg/L At a broad regional scale, arsenic concentrations exceeding 10 μg/L appear to be more frequently observed in the western United States than in the eastern half Arsenic concentrations in ground water of the Appalachian Highlands and the Atlantic Plain generally are very low ( 1 μg/L) Concentrations are somewhat greater in the Interior Plains and the Rocky Mountain System Investigations of ground water in New England, Michigan, Minnesota, South Dakota, Oklahoma, and Wisconsin within the last decade suggest that arsenic concentrations exceeding 10 μg/L are more widespread and common than previously recognized Arsenic release from iron oxide appears to be the most common cause of widespread arsenic concentrations exceeding 10 μg/L in ground water This can occur in response to different geochemical conditions, including release of arsenic to ground water through reaction of iron oxide with either natural or anthropogenic (ie, petroleum products) organic carbon Iron oxide also can release arsenic to alkaline ground water, such as that found in some felsic volcanic rocks and alkaline aquifers of the western United States Sulfide minerals are both a source and sink for arsenic Geothermal water and high evaporation rates also are associated with arsenic concentrations 10g/L in ground and surface water, particularly in the west

Semianalytical Computation of Path Lines for Finite‐Difference Models

Abstract: A semianalytical particle tracking method was developed for use with velocities generated from block centered finite-difference ground-water flow models. The method is based on the assumption that each directional velocity component varies linearly within a grid cell in its own coordinate directions. This assumption allows an analytical expression to be obtained describing the flow path within an individual grid cell. Given the initial position of a particle anywhere in a cell, the coordinates of any other point along its path line within the cell, and the time of travel between them, can be computed directly. For steady-state systems, the exit point for a particle entering a cell at any arbitrary location can be computed in a single step. By following the particle as it moves from cell to cell, this method can be used to trace the path of a particle through any multidimensional flow field generated from a block-centered finite-difference flow model.