摘要:

AbstractThe authors have recently used several innovative sampling techniques for ground water monitoring at hazardous waste sites. Two of these techniques were used for the first time on the Biscayne Aquifer Super‐fund Project in Miami, Florida. This is the largest sampling program conducted so far under the U.S. Environmental Protection Agency (EPA) Superfund Program.One sampling technique involved the use of the new ISCO Model 2600 submersible portable well sampling pump. A compressed air source forces water from the well into the pump casing and then delivers it to the surface (through a pulsating action). This pump was used in wells that could not be sampled with surface lift devices.Another sampling technique involved the use of a Teflon manifold sampling device. The manifold is inserted into the top of the sampling bottle and a peristaltic pump creates a vacuum to draw the water sample from the well into the bottle. The major advantage of using this sampling technique for ground water monitoring at hazardous waste sites is the direct delivery of the water sample into the collection container. In this manner, the potential for contamination is reduced because, prior to delivery to the sample container, the sample contacts only the Teflon, which is well‐known for its inert properties.Quality assurance results from the Superfund project indicate that these sampling techniques are successful in reducing cross‐contamination between monitoring wells. Analysis of field blanks using organic‐free water in contact with these sampling devices did not show any concentration at or above the method detection limit for each priority po

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1984.tb00890.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractFor regions of shallow ground water, a shallow well point sampler can provide cost‐effective sampling of contaminant plumes. A miniature well point sampler allows rapid sampling of ground water down to a maximum depth of 12 feet below grade. A high ratio of striking force to cross‐sectional area of the shaft enables the well point to penetrate soils grading from silt through sand to fine gravel. Three slot sizes have proved satisfactory for the slotted well point. For fine gravel through silty sand, a receiver flask serving as a silt trap with a hand pump can withdraw water samples. For silt or clay, a special shielded point is used to expose a porous screen upon withdrawal of the shaft. The points can be left imbedded in the strata and a vacuum drawn to recover a sample under saturated or unsaturated conditions.Such a sampler has been shown to be effective in tracing plumes from individual on‐site septic systems and hazardous waste sites. The text describes a simple procedure for plume analysis and description of the extent of dewatered strata near the point based upon different sample volumes. The probe has been used with conductivity meters and fluorometers for profiling subsurface plumes. A cost comparison is shown between monitoring well installation and the portable well point for varying sample frequency and

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1984.tb00891.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractHydrogeologic and ground water quality data obtained from a gas‐driven multilevel sampler system and a polyvinyl chloride (PVC) monitoring well nest with the same aquifer communication intervals are compared. All monitoring points are in close proximity to each other.The study was conducted at an eight‐acre uncontrolled hazardous waste site. The site is located in an alluvial valley composed of approximately 40 feet of alluvium overlying shale bedrock. The ground water at the site is contaminated with various organic constituents.A ground water monitoring network consisting of 26 conventional monitoring wells, nine observation well points, and six multilevel gas‐driven samplers was established to characterize the hydrogeologic regime and define the vertical and horizontal extent of contamination in the vicinity of the abandoned chemical plant. As part of this study, a multilevel monitoring system was installed adjacent to a well nest. The communication zones of the multilevel samplers were placed at the same elevation as the sand packs of the well nest. The multilevel sampler system and well nest are located in a contaminated area directly downgradient of the site. A comparison of the vertical head distribution and ground water quality was performed between the well nest and the multilevel sampling system.The gas‐driven multilevel sampling system consists of three gas‐driven samplers that monitor separate intervals in the unconsolidated materials. The well nest, composed of two PVC monitoring wells in separate boreholes, has the same communication interval as the other two gas‐driven samplers.Hydraulic head information for each multilevel sampler was obtained using capillary tubing. This was compared with heads obtained from the well nest utilizing an electric water level indicator.Chemical analyses from the PVC and multilevel sampler wells were performed and compared with one another. The analyses included organic acids, base neutrals, pesticides, PCBs, metals, volatile organics, TOX, TOC, CN, pH and specific

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1984.tb00892.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractA suction side sample collector (SSSC) is a contrivance installed hydraulically ahead of the intake port of a pumping device. This paper describes construction and operational details of SSSCs fitted to a submersible pump with packer for use in a 6‐inch cased borehole, an air lift pump with packer for use in a 1‐inch or 2.5‐inch cased borehole, a bladder pump for use in a casing of 2‐inch or greater diameter, and a jet pump with packer for use in a 2‐inch cased borehole.Each form of SSSC has been thoroughly tested in ground water quality sampling for volatile organic chemicals. Comparative data for samples collected with the SSSCs and conventional sample collecting gear are presented. The SSSC is demonstrated to be superior to other methods of collecting volatile organic chemical samples owing to its freedom from contamination by the pump delivery line and to its mode of collecting the sample from a position in the well remote from disturbance by the pumping technique.SSSCs are conveniently decontaminated, easily transported, and can be used to deliver samples to the laboratory while still at formation pressure. The air‐lift pumps, described in this paper for use with SSSCs in 1‐ and 2.5‐inch casings, have pumping capacities greater than obtained by other methods that can operate in these small casings. Discharge rates of up to 2 gpm are routinely achieved with the 1‐inch model and higher rates are common With the 2.5‐inch model. The use of packers with these pumps reduces the time needed to replace the water in the casing with fresh water

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1984.tb00893.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractIn the past 30 to 40 years, floodplain areas of large rivers, such as the Missouri River, have been extensively used for large industrial and municipal landfills. Many of these sites are now causing varying degrees of ground water contamination. Rapid geophysical characterization techniques have proven useful for delineation of anomalous areas indicative of potential contaminant plumes. These methods have also resulted in a cost effective approach to the location and number of monitoring wells.An effective technique to initially characterize ground water contamination at such landfills along the Missouri River in northwestern Missouri involved a combination of electrical resistivity and electromagnetic conductivity methods. Resistivity was used to obtain soundings of the alluvium by using a modified Wenner array and to corroborate shallow electromagnetic conductivity measurements by using short Wenner array electrode spacings.Upon confirmation of similar measurements of the upper soils for the two methods, numerous electromagnetic conductivity traverses were made at each landfill site. The data generated from these surveys were graphed and contoured to delineate anomalous areas. Based on the geophysical study, a ground water monitoring well network was then designed for each landfill.As a result, a minimal number of wells were required to initially characterize the ground water quality at these two sites. In general, analysis of water samples from these wells displayed good correlation with the geophysical results.

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1984.tb00894.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractA total of four vertical electrical soundings were conducted in a layered andesitic rock aquifer known in places to yield ground water with total dissolved solids (TDS) in excess of 2,000 milligrams per liter (mg/L). The objective of the soundings was to locate zones of moderate to high permeability but with acceptable chemical quality.The resistivity of a geologic unit is a function that includes the quantity of total dissolved solids in the interstitial water and the distribution of the water within the unit. Thus, the resistivity of most granular soils and rocks is controlled more by porosity, water content and water quality than by the conductivity of the matrix materials.The electrical data delimited a drill site where it was believed that ground water of acceptable chemical quality could be expected. Completion and test pumping of two exploration wells confirmed the electrical sounding results.The first test well drilled prior to the survey yielded only small amounts of ground water with total dissolved solids in excess of 2,000 mg/L. The second exploration well drilled at the site as a result of the electrical study yielded in excess of 100 gallons per minute of ground water with total dissolved solids of 830 mg/L.

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1984.tb00895.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1984.tb00896.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe hydraulic properties of lake beds control the interactions between lakes and ground water systems, but these properties are normally difficult to measure directly. The authors’method combines seismic reflection and electrical measurements to map the relative hydraulic conductivity of lake bed sediments. A shipboard seismic profiling system provides sediment thickness, while a towed electrical array yields longitudinal conductance and electrical chargeability. The sediment's leakance (hydraulic conductivity/thickness) can be calculated from the longitudinal conductance data. Leakance may then be converted to relative hydraulic conductivity through the seismically derived sediment thicknesses. Simultaneously acquired electrical chargeability provides an independent measure of clay content. The seismic and electrical systems are computer automated and yield production rates of approximately five line‐kilometers/hour or 300 electrical soundings/hour. The systems provide continuous hydraulic information along the ship track rather than the point information derived from coring.The procedure and systems have been used to map the bed of Lake Michigan offshore from an area of heavy pumpage. This location has been chosen to test the method because lake water has intruded the aquifer in plumes largely controlled by lake bed hydraulics. Mapping these plumes onshore permits the inference of the spatial distribution of offshore hydraulic conductivities. Offshore seepage measurements and numerical, chemical transport modeling of this site have confirmed the reliability of the geophysically derived hydraulic conductivities and have also demonstrated the improvement in numerical results achieved through the availability of spatially determined hydraulic conductivit

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1984.tb00897.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1984.tb00898.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractAtomic Energy of Canada Limited is constructing an Underground Research Laboratory (URL) at a depth of 250m in a plutonic rock body near Lac du Bonnet, Manitoba. The facility is being constructed to carry out a variety of in situ geotechnical experiments as part of the Canadian Nuclear Fuel Waste Management Program.A unique feature of the URL, in comparison to other similar facilities such as the Stripa Mine in Sweden, is that it is to be constructed below the ground water table in a previously undisturbed plutonic rock body. One of the main research objectives of the project is to develop and validate comprehensive three‐dimensional models of the hydrogeology of the rock mass encompassing the URL site. These models will be used, before excavation of the URL shaft begins, to predict the hydrogeological perturbation that will be created by the excavation of the shaft and the horizontal working levels below the ground water table. As a model‐validation exercise, these drawdown predictions will be compared with actual hydrogeological perturbations that will be monitored at the study area over the next several years by an extensive network of instrumented boreholes.Measurements made in an array of boreholes extending to depths of 1,000m on the 4.8 km2study area have established that the permeability distribution in three major extensive subhorizontal fracture zones controls the movement of ground water within the rock mass. Several types of multiple‐interval completion systems have been installed in the boreholes to monitor the three‐dimensional, physico‐chemical hydrogeological conditions within the fractured rock mass. These include conventional piezometer nests and water‐table wells that have been installed in shallow holes (less than 30m deep), and multiple‐packer/ multiple‐standpipe piezometers and multiple‐interval casing systems installed in deeper holes (30 to 1,000m deep). An automated, electronic, piezometric pressure‐monitoring system has been designed to collect continuous measurements from 75 isolated hydrogeological monitoring positions within the rock mass. Another 200 positions are being monitored frequently using a variety of techniques. Piezometric data have been collected from this monitoring network to establish baseline conditions prior to any excavation into the rock mass. These data have also been used to determine the steady‐state, three‐dimensional ground water flow regimes that exist at the URL site u

ISSN:1069-3629    

DOI:10.1111/j.1745-6592.1984.tb00899.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY