ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1985.tb00934.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1985.tb00935.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1985.tb00936.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractIron‐precipitating bacteria are frequently cited as being involved in economically serious well and aquifer degradation that may also have a public health impact. Quantifying the populations of the iron‐precipitating bacteria present in ground water is a complex problem not yet resolved. A survey of historical and modern environmental literature provides numerous descriptions of iron bacteria in aquifers and wells, along with physicochemical data collected during bacterial sampling. These data are not conclusively linked with iron bacteria occurrence. Iron bacteria is a concept encompassing many genera and species of bacteria with varying morphology and physiology. Methods to detect bacteria and to quantify bacterial biomass in aquifers are being developed, but representative sampling remains a problem. Predictive analysis of iron bacterial growth awaits additional physiological and sampling resea

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1985.tb00937.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractAs high‐voltage, direct‐current (HVDC) electrical power transmission technology advances, the siting and design of the grounded return electrodes become critical factors. Electrode sites should be chosen where surrounding geologic conditions will not unfavorably channel large earth currents and harmfully affect nearby populations. An optimum site allows direct contact between the electrode and a large volume of a stable, low‐resistivity material. A saturated alluvial zone between dry surface soils and an underlying crystalline bedrock is an ideal material for containing the current flow from the electrode.A hydrogeologic investigation was conducted to delineate the saturated zone in several alluvial valleys in the southwestern desert region. Regional ground water flow directions, water quality, and seasonal fluctuations of the water table elevations were determined. The structural shape and topography of the crystalline basement beneath the valleys were interpreted from gravity data. Iterative forward‐modeling of the data provided a low‐cost means of deducing the volume of the lightweight alluvium. Electrical resistivity surveys were completed to measure the lateral and vertical variations in soil resistivities throughout the valleys. The geophysical data were used to extend the known hydrologic information into areas with no wells.Composite models of the saturated zones in each valley were produced by integrating gravity interpretations with hydrologic and resistivity results. The composite models were used to predict current density in the ground that would be associated with a HVDC electrode. This methodology proved to be a cost‐effective means of siting electrodes in a suitable geologic environment that would minimize their detrimen

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1985.tb00938.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe recognition and assurance of the quality of ground water monitoring data are crucial to the correct assessment of the magnitude and extent of a ground water contamination problem. This article addresses an approach being developed to systematically evaluate the quality of a given set of ground water monitoring data collected during site investigation/ remedial action efforts. The system consists of a checklist of criteria, grouped into four major categories, which can be applied to laboratory or field measurements.The first category, basis of measurement, considers whether the appropriate sampling, boring and/or analytical methods were chosen to obtain the measurement and the limitations of each method. Secondly, application of the method is assessed. This includes examination of the extent to which procedures were correctly performed, the use of quality control measures and calibration, and possible sources of error in the measurements. Third, evaluation of applied statistical methods is made, with consideration given to which statistics are meaningful in a given context and whether measurements are reproducible. The final category, corroborative information, considers whether independent data or other information are available that add credibility to the values measured.In this approach, a “high quality” data value is defined as one in which accuracy is supported by meeting the preceding criteria. When accompanied by precision information, high quality data allow for defensible assessments and actions. This evaluation system is useful in developing monitoring programs and in guiding documentation of field and laboratory methods during data collection. It relies heavily on experienced judgment and can be catalyst for the beneficial exchange of knowledge and ideas among ground water profession

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1985.tb00939.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe potential and the problems for geophysical monitoring programs at waste disposal sites are discussed. No data are presented, but the expectations, design criteria and implementation of a geophysical monitor are examined for a hypothetical landfill. We conclude that any geophysical monitor must be designed to allow for future changes in the physical setting, geophysical technology and the personnel who will record, process and interpret the data. This suggests that permanent installations be kept to a minimum, and that a high priority be given to simplicity and reliability. It is also important that the detection limits of the monitor be clearly established, that the noise levels in readings unrelated to changes in contamination levels are well defined and that the monitor is integrated into an overall hydrogeological monitoring program.

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1985.tb00940.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractNoncontaminating procedures were used during the hollow‐stem auger installation of 12 observation wells on three hazardous waste sites in Kansas. Special precautions were taken to ensure that water samples were representative of the ground water in the aquifer and were not subjected to contamination from the land surface or cross contamination from within borehole. Precautions included thorough cleaning of the hollow‐stem auger and casing, keeping drill cuttings from falling back into the borehole while drilling, and not adding water to the borehole. These procedures were designed to prevent contamination of the ground water during well installation.Because the use of water during well installation could contaminate the aquifer or dilute contaminants already present in the aquifer, two methods of well installation that did not introduce outside water to the borehole were used. The first method involved using a slotted 3/4‐inch coupling that was attached to the bit plate of the hollow‐stem auger, allowing formation water to enter the auger, thereby preventing sand‐plug formation. This method proved to be adequate, except when drilling through clay layers, which tended to clog the slotted coupling. The second method involved screened well swab that allowed only formation water to enter the hollow‐stem auger and prevented sand from plugging the hollow‐stem auger when the bit plat

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1985.tb00941.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1985.tb00942.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY