bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solute Transport Simulation of Aquifer Restoration after In Situ Uranium Mining
Authors: Osiensky James L. , Peterson Kent A. , Williams Roy E. 
Published: February 2007

AbstractIn situ mining of uranium was conducted in two well fields at a research and development site in the Powder River Basin of Wyoming from March 1980 to July 1981. Subsequent aquifer restoration activities continued until December 1982. During the restoration phases of operation, complex pumping‐injection schemes, necessitated by the absence of adequate disposal facilities, were employed by the mining company in an attempt to satisfy the conditions imposed by the mine permit.An analytical “Random Walk” solute transport model was used to simulate mass transport mechanisms associated with the pumping‐injection schemes used in the A‐1 well field. Because the hydrogeology at the site is relatively simple; a more sophisticated model requiring extensive calibration was not required. The model was not used as a “predictive” tool, but as an analytical supplement to existing water quality and hydrogeologic data. As such, it provided a very useful and inexpensive means by which to evaluate the adequacy of the restoration techniques employed at the site and the effectiveness of the water quality monitoring program.Model simulations suggest that the restoration methods used by the mining company were not adequate to remove residual lixiviant and actually tended to displace contaminants to a circular region between the well field and peripheral monitoring wells. An analysis of the water quality and operational history at the site suggests that the model results may be accurate. If this is true, the postrestoration water quality data collected at the site may not be an accurate measure of the effectiveness of aquifer restoration.
Pesticides in Nebraska's Ground Water
Authors: Spalding R.F. , Burbach M.E. , Exner M.E. 
Published: February 2007

AbstractMore than 2263 well water samples were collected throughout Nebraska and analyzed for pesticides. Thirteen and one‐half percent contained detectable levels of atrazine, but only 22 wells exceeded the health advisory of 3.0 ppb. Although the samples came from almost every county in the state, this sampling is not based solely on a randomly selected group of wells. The highest frequency of detections occurred in irrigated corn‐growing areas with less than 50 feet to ground water. These areas were sampled at a greater frequency than the less vulnerable areas. Cyanazine, together with the additional triazines — simazine, propazine, prometone, and ametryne, also were detected in some well waters; however, their frequency of detection was well below that of atrazine. The triazine metribuzin was not detected.Alachlor, propachlor, and metolachlor also were detected in trace levels in several wells. Five of 2072 samples analyzed for alachlor exceeded the health advisory of 0.4 ppb. Almost all of the contaminated wells were in vulnerable areas. The relatively high frequency of propachlor detections occurred in predominately irrigated corn‐growing areas, rather than in areas where propachlor is traditionally applied.The factors that appear most directly involved in the observed distribution of pesticides in ground water are the intensity of areal usage, pesticide persistence and mobility, irrigation, soil drainage capacity, and depth to ground water.Fifteen pesticide residues were detected during this study. If ethylene dibromide and carbon tetrachloride, which were detected in ground water adjacent to grain elevators are included, a total of 17 pesticide residues have been detected in Nebraska's ground water.
Ground Water Loading of Pesticides in the Atlantic Coastal Plain
Authors: Shirmohammadi A. , Magette W.L. , Brinsfield R.B. , Staver K. 
Published: February 2007

AbstractPollution of ground water by agricultural practices has gained considerable attention in recent years. Mathematical models have been developed to evaluate the effects of agricultural best management practices on pesticide transport to ground water. The GLEAMS model was evaluated to determine its suitability for use in predicting managerial effects on pesticide leaching from agricultural systems in the Atlantic Coastal Plain. Model predictions of pesticide concentrations in percolation from the root zone were compared to observed concentrations in ground water beneath field‐sized areas. The model underpredicted runoff from these areas. Model predictions were used to produce rankings of the magnitudes of pesticide losses that paralleled rankings of observed ground water data in some cases but not others. Differences in observed and predicted rankings were assessed to be the result of sampling schedule inefficiences. The magnitudes of predicted pesticide concentrations in leachate from the root zone were three to seven times higher than observed concentrations in shallow ground water. Results support the use of GLEAMS for comparison of managerial effects on pesticide movement to ground water if appropriate limitations are recognized.
Coproduced Ground Water Treatment and Disposal Options During Hydrocarbon Recovery Operations
Authors: Stover Enos L. 
Published: February 2007

AbstractReinjection of untreated ground water during hydrocarbon recovery operations provides for economical water handling and can accelerate the recovery of the free hydrocarbons. However, considering current regulatory trends, water containing dissolved hydrocarbon constituents would require treatment prior to reinjection into the aquifer. The disposal of coproduced ground water is dependent on several factors, including the volume of water, level of treatment required, and availability of disposal options. Disposal options include reinjection, discharge to surface water, and beneficial use. This paper presents treatment and disposal options for coproduced water during hydrocarbon recovery operations including cost comparisons for a particular case study.Treatment technologies for oil/water separation, inorganics and heavy metals removal, and dissolved hydrocarbon removal are presented. The primary technologies discussed for dissolved hydrocarbon removal include air stripping, activated carbon adsorption, biological treatment, and combinations of these technologies. Consideration of the use of existing refinery waste water treatment facilities for ground water treatment should be encouraged where applicable. However, separate treatment facilities are usually required because the use of existing on‐site treatment facilities is usually not feasible because of the volume of water produced during large recovery projects and the effectiveness of existing treatment facilities. A specific case example is presented with costs for applying different technologies including the use of existing on‐site facilities. Treatment costs ranged between 44 cents to $2.82 per thousand gallons (11 cents to 75 cents per thousand liters) of water treated for the specific technologies examined herein.
Applications of Dual‐Wall Reverse‐Circulation Drilling in Ground Water Exploration and Monitoring
Authors: Strauss M. Fred , Story Steve L. , Mehlhorn Norman E. 
Published: February 2007

AbstractDual‐wall reverse‐circulation drilling uses flush‐threaded double‐wall drill pipe and high‐pressure air to provide continuous return of formation and water samples. Cuttings and formation waters are not contaminated with drilling additives or mixed with other borehole material. Up‐hole velocity of about 70 ft/sec provides reliable logging of water, mineral or contaminant‐bearing strata. Water samples representative of specific strata may be airlifted or bailed to the surface.In the percussion hammer system, dual‐wall drill pipe is advanced through chiefly unconsolidated material by the percussion action of an above‐ground pile hammer. The borehole is drilled and temporarily cased in one pass. Wells or monitoring devices are installed as the drill pipe is hydraulically retracted during construction. A rotary head may be adapted as an option to allow dual‐wall rotary drilling into consolidated or crystalline formations through a percussion hammer drill string temporarily left in place as a conductor.The complex geology and variety of geoenvironmental problems in southern California has provided a testing ground for dual‐wall drilling on hazardous material site investigations. Several case histories have demonstrated the capabilities and versatility of this method, including: (1) the installation of 4‐inch and 6‐inch diameter gasoline monitoring and recovery wells through gravels and cobbles at a filling station where hollow‐stem auger drilling failed; (2) the confirmation of a dry borehole initially drilled by direct rotary at a landfill; and (3) multiple installations of monitoring devices through municipal refuse at a city of Los Angeles landfill.
Investigation of Failure Mechanisms and Migration of Organic Chemicals at Wilsonville, Illinois
Authors: Herzog B.L. , Griffin R.A. , Stohr C.J. , Follmer L.R. , Morse W.J. , Su W.J. 
Published: February 2007

AbstractGround water contamination was discovered in 1981 in a monitoring well at the Earthline disposal facility near Wilsonville, Illinois. Organic chemicals had migrated at a rate 100 to 1000 times greater than predicted when the site received its permit to operate in 1978. Postulated failure mechanisms included migration through previously unmapped permeable zones, subsidence of an underground mine, organic‐chemical and clay‐mineral interactions, acid‐mine drainage and clay interactions, trench‐cover settlement, and erosion.In this investigation, the Illinois State Geological Survey found the primary reason for the rapid migration: the presence of previously undetermined fractures and joints in glacial till. The inaccurate predictions of hydraulic conductivity were based on laboratory‐determined values that did not adequately measure the effects of fractures and joints on the transit time calculations. Field‐measured hydraulic conductivity values were generally 10 to 1000 times greater than their laboratory‐measured counterparts, thus largely accounting for the discrepancy between predicted and actual migration rates in the transit time calculations. The problem was compounded, however, by the burial of liquid wastes and by trench covers that allowed excess surface runoff to enter the trenches. Organic‐chemical and clay‐mineral interactions may also have exacerbated the problem in areas where liquid organic wastes were buried.
The Hydropunch™: An In Situ Sampling Tool for Collecting Ground Water from Unconsolidated Sediments
Authors: Edge Russel W. , Cordry Kent 
Published: February 2007

AbstractThe Hydropunch™ is a stainless steel and Teflon® sampling tool that is capable of collecting a representative ground water sample without requiring the installation of a ground water monitoring well. To collect a sample, the Hydropunch (Patent #4669554) is connected to a small‐diameter drive pipe and either driven or pushed hydraulically to the desired sampling depth. As the tool is advanced, it remains in the closed position, which prevents soil or water from entering the Hydropunch. Once the desired sampling depth is obtained, the tool is opened to the aquifer by pulling up the drive pipe approximately 1.5 feet (0.46m). In the open position, ground water can flow freely into the sample chamber of the tool. When the sample chamber is full, the Hydropunch is pulled to the surface. As the tool is retracted, check valves close and trap the ground water in the sample chamber. At the surface the sample is transferred from the Hydropunch to an appropriate sample container. The tool is a fast, inexpensive alternative for collecting ground water samples from a discrete interval. It is excellent for vertical profiling or defining the areal extent of a contaminant plume.
Subsurface Transport of Inorganic and Organic Solutes from Experimental Road Spreading of Oil‐Field Brine
Authors: Bair E. Scott , Digel Robert K. 
Published: February 2007

AbstractA study designed to evaluate ground water quality changes resulting from spreading oil‐field brine on roads for ice and dust control was conducted using a gravel roadbed that received weekly applications of brine eight times during the winter phase and 11 times during the summer phase of the study. A network of 11 monitoring wells and five pressure‐vacuum lysimeters was installed to obtain ground water and soil water samples. Thirteen sets of water‐ quality samples were collected and analyzed for major ions, trace metals, and volatile organic compounds. Two sets of samples were taken prior to brine spreading, four sets during winter‐phase spreading, five sets during summer‐ phase spreading, and two sets during the interim between the winter and summer phases. A brine plume delineated by elevated specific‐conductance values and elevated chloride concentrations developed downgradient of the roadbed during both the winter and summer phases. The brine plume caused chloride concentrations in ground water samples to exceed U.S. EPA public drinking‐water standards by two‐fold during the winter phase and five‐fold during the summer phase. No other major ions, trace metals, or volatile organic compounds exceeded the standards during the winter or summer phases. More than 99 percent dilution of the solutes in the brine occurred between the roadbed surface and the local ground water flow system. Further attenuation of calcium, sodium, potassium, and strontium resulted from adsorption, whereas further attenuation of benzene resulted from volatilization and adsorption.
A Surface‐Flux Measurement Method for Screening Contamination from Volatile Organic Compounds
Authors: Karp Kenneth E. 
Published: February 2007

AbstractMeasurement of the vapor flux from volatile organic compounds (VOCs) provides a rapid means for screening large areas of potential contamination. The vapor flux is determined from the rate of VOC concentration buildup inside a 3.1L accumulator device that is sealed to the surface of the contaminated soil. After the VOC concentrations are allowed to increase for a few minutes, they are analyzed with a portable gas chromatograph or a total organic vapor analyzer.The measurement approach was evaluated at a field site in an area where the ground water and soil had been impacted with Jet Fuel No. 4 (JP‐4). An indication of the areal extent of impact was determined by mapping the surface VOC vapor flux. The pattern revealed by the flux measurements was found to coincide, in rough outline, with the known extent of toluene concentrations in the ground water and with conventional soil‐gas survey results. In addition, a mathematical model describing VOC diffusion into the accumulator device was verified by performing laboratory measurements of the surface VOC vapor flux on a sandbox designed to simulate a hazardous waste site.
Effects of Access Tube Material and Grout on Neutron Probe Measurements in the Vadose Zone
Authors: Keller B. R. , Everett L. G. , Marks R. J. 
Published: February 2007

AbstractA test‐stand experiment was conducted on neutron probe measurements using steel and Schedule 40 PVC access tubes to determine the effect of backfill grout in boreholes. The experiment used a moveable simulated vadose zone. Access tubes and grout do have masking effects on vadose zone measurements, but vadose zone moisture was detected through all configurations tested. Steel tubing has a smaller masking effect than PVC tubing. The masking effect of grout increased with borehole diameter. Although this experiment produced numerical results, conclusions drawn are qualitative in nature, rather than a quantitative calibration of the technique.
Assessment of Pesticides in Upstate New York Ground Water: Results of a 1985‐1987 Sampling Survey
Authors: Walker Mark J. , Porter Keith S. 
Published: February 2007

AbstractThe New York State Water Resources Institute at Cornell University undertook a two‐year sampling survey of pesticides in ground water beginning in 1985. The survey focused on areas where combinations of agricultural pesticide use, soil texture, and ground water occurrence seemed likely to lead to leaching. The sampling survey included samples from four types of sampling points: (1) monitoring wells; (2) existing water supply wells; (3) test holes; and (4) tile drains. The monitoring wells were sampled repeatedly throughout the project to attempt to characterize temporal changes in water quality corresponding with seasonal changes in ground water levels. The pesticides studied for this project were atrazine, alachlor, cyanazine, metolachlor, carbaryl, carbofuran (and a metabolite, 3‐hydroxy carbofuran), and simazine. All, except for carbaryl, have been found in ground water in other sampling surveys in the United States.The results of the sampling survey did not reflect the careful choices of enviromental characteristics and pesticide use that seemed likely to lead to leaching. Residues of three pesticides were detected in six single samples from separate sources at four of the 30 sites tested. Three of the six samples came from shallow test holes that were used to sample the shallowest possible saturated soils beneath fields. The three pesticides detected were atrazine, simazine, and 3‐hydroxy carbofuran. Of the six samples, a single sample from a test hole contained atrazine concentrations equal to the current federal health advisory for long‐term exposure to atrazine (3 ppb).The remaining detections were between the limit of detection for analytical methods and the federal health advisory for each pesticide. The federal health advisories were formulated after the end of the project. Analytical methods may have been insensitive with respect to these advisories. Sampling results from other surveys suggest that many detections of the same pesticides lie below the limits of detection used for this sampling survey.A possible explanation for the lack of detections, given the design of the sampling survey, may lie in the agricultural practices noted at sampled sites. Most of the farm managers rotated their crops and pesticides on many small fields. Although the environmental conditions chosen for sampling sites were expected to lead to contamination, reported pesticide applications varied from year to year and field to field according to rotational schedules. The inconsistency of applications from year to year may explain the lack of detections (at the limits of quantification used for analyses) noted in this sampling survey.
A Ground Water Monitoring Study for Pesticides and Nitrates Associated with Golf Courses on Cape Cod
Authors: Cohen Stuart Z. , Nickerson Susan , Maxey Robert , Jr. Aubry Dupuy , Senita Joseph A. 
Published: February 2007

AbstractScientists and regulators in the United States began emphasizing the study of pesticides in ground water in 1979 and 1980. The scientific community began to emphasize the study of nitrates in ground water as a result of fertilization in the mid to late 1970s. By the mid 1980s. tens of thousands of wells were found to contain elevated nitrate concentrations and detectable concentrations of pesticides. Few, if any, of the data were collected from wells associated with the nation's 13,000 golf courses.Golf is popular on Cape Cod, an area that depends on a hydrogeologically vulnerable aquifer system as its principal source of drinking water. Pesticides and fertilizers are applied to golf courses, often at high rates on greens and tees. Therefore the EPA, the Barnstable County government, and several local golf course superintendents collaborated on a study of the impact of golf course turf management on ground water quality.Nineteen monitoring wells were installed upgradient and in greens, tees, and fairways on four golf courses. Selected soil core samples were collected and analyzed. Four to six rounds of ground water samples were collected over one and a half years and analyzed for 17 pesticides and related chemicals; nitrate‐N samples were collected at least monthly. Seven of the 17 chemicals were never detected. The most frequently detected chemical‐dichlorobenzoic acid ‐ probably had been an impurity in herbicide formulations. Chlordane was detected in several wells at concentrations exceeding the health advisory level, perhaps due either to repeated heavy applications coupled with preferential flow of the bound/particulate phase and /or cross contamination during well installation. The results show no cause for concern about use of these currently registered pesticides.Nitrate‐N concentrations were generally below the 10 ppm federal MCL, with some exceptions. Overall, nitrate‐N concentrations decreased in response to lower application rates and use of slow‐release fertilizer formulations.
Monitoring Well Completion Evaluation with Borehole Geophysical Density Logging
Authors: Yearsley E.N. , Crowder R.E. , Irons L.A. 
Published: February 2007

AbstractGrout continuity and the location of the bentonite seal and sand pack in PVC‐cased monitoring wells can be evaluated with cased‐hole geophysical density logs. This method relies upon density contrasts among various completion conditions and annular materials. Notably, the lack of annular material behind pipe (i.e., void space) creates a low‐density zone that is readily detected by borehole density measurements.Acoustic cement bond logging has typically been applied to the evaluation of cement in the annular space of completed oil and gas production wells, and in some cases to ground water monitoring wells. These logs, however, can only be obtained in the fluid‐filled portion of the borehole, and their interpretation is severely hindered by the presence of the micro‐annulus between casing and cement. The influence of the micro‐annulus on cement bond logs can be mitigated in steel‐cased wells by pressurizing the wellbore during acquisition of the log, but this procedure is not feasible in PVC‐cased monitoring wells. The micro‐annulus does not affect cased‐hole density logs or their interpretation.Empirical measurements made in the laboratory with density probes provide information on their depths of investigation and response to specific completion conditions. These empirical data, and general knowledge of the density of annular completion materials (sand, bentonite, cement), are used to support interpretations of cased‐hole density logs acquired in the field. Three field examples demonstrate the applicability of geophysical density logs to the evaluation of PVC‐cased monitoring well completions.
Reduction of Nitrate Loadings to Ground Water
Authors: Shirmohammadi Adel , Magette William L. , Shoemaker Leslie L. 
Published: February 2007

AbstractNon‐point source pollution of ground water systems has become a national concern in recent years. Researchers and regulatory agencies are investigating the source and processes of the contamination. Agricultural best management practices (BMPs) traditionally developed to reduce non‐point source pollution of surface water resources are being investigated for their impact on ground water quality. This study used the CREAMS model to simulate the long‐term effects of seven different BMPs on nitrate nitrogen (NO3‐N) loadings to a shallow, unconfined ground water system. Two representative watersheds, 5.8 and 8.9 hectares (14.3 and 22 acres) in area, in the Coastal Plain physiographic region of Maryland were selected for study. Soils in these watersheds belong to the Matapeake silt loam series and have moderate infiltration capacity. Results from this study indicated that BMPs used in conjunction with winter cover (barley) reduced NO3‐N leaching to the ground water system. It was also found that turfgrass reduced surface losses of water and nitrogen, but increased leaching losses of water and NO3‐N significantly. All of the BMPs simulated in this study resulted in leachate NO3‐N concentrations exceeding 10 ppm, the U.S. EPA health standard for public drinking water, indicating a need for alternate practices for reducing nitrate leaching.