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1.
Ronald Schalla David A. Myers Mary Ann Simmons John M. Thomas Antony P. Toste 《Ground Water Monitoring & Remediation》1988,8(3):90-96
Four state-of-the-art ground water sampling systems were analyzed to determine their reliability in providing representative samples of the volatile chlorinated hydrocarbons trichloroethylene (TCE), perchloroethylene (PCE), and 1,1,1-trichloroethane (TCA) from a simulated monitoring well. The sampling systems studied represent four commonly used devices, including a stainless steel and Teflon® piston pump, a Teflon bailer, a Teflon bladder pump, and a PVC air-lift pump.
Controlled laboratory sampling experiments were conducted in a tank and well test chamber designed to approximate field conditions. A well purging and sampling procedure was used in the test apparatus to determine the accuracy and precision of each device for detecting low concentrations of the compounds in ground water. The compounds selected are some of the most ubiquitous hazardous contaminants found in shallow aquifers near hazardous waste sites throughout the United States.
No significant statistical difference was found among the four sampling systems in detecting the compounds. 相似文献
Controlled laboratory sampling experiments were conducted in a tank and well test chamber designed to approximate field conditions. A well purging and sampling procedure was used in the test apparatus to determine the accuracy and precision of each device for detecting low concentrations of the compounds in ground water. The compounds selected are some of the most ubiquitous hazardous contaminants found in shallow aquifers near hazardous waste sites throughout the United States.
No significant statistical difference was found among the four sampling systems in detecting the compounds. 相似文献
2.
W.M. Schuh R.L. Cline M.J. Kosse D.W. Sletton 《Ground Water Monitoring & Remediation》1997,17(1):81-90
A field experiment was conducted to examine the effect of short-term (one minute) contact of pesticide-laden water with a polyvinyl chloride (PVC) bailer on quantitative laboratory measurements of seven pesticide concentrations in distilled water samples subsequently decanted from the bailer. Pesticides were tested at two initial concentrations (low. based on current FPA maximum contaminant levels, or MCL: and high, based on a multiple of approximately lour times the MCL). Pesticide species included bromoxynil, diclofop-m, dimethoate. MCPA, methyl parathion, propiconazole, and trifluralin. Dimethoate recoveries were poor for all treatments. For all other pesticides there was no systematic difference between pesticide concentrations measured before and after bailer contact. Effectiveness of bailer decontamination treatments consisting of distilled water rinse alone was related to water solubility (S) for each species. Distilled water samples decanted from a rigid PVC bailer following initial bailer contact with pesticide-spiked water, and after the bailer had been cleaned with a single distilled water rinse, had measured pesticide concentrations of less than 2 percent of the pesticide concentration in the initial pesticide-spiked water, regardless of S. A single distilled water rinse effectively removed all trace of contaminants having S> 500 mg/L. Multiple distilled water rinses, and multiple distilled water rinses followed by 15 bailings of a well, effectively removed all trace of contaminants having S> 50 mg/L. Below threshold S, cleaning effectiveness decreased as a power function of S. 相似文献
3.
Barry S. Mines John L. Davidson David Bloomquist Thomas B. Stauffer 《Ground Water Monitoring & Remediation》1993,13(1):115-120
In the BAT ground water sampling system, a stainless steel probe with a porous filter element is pushed vertically to the desired sampling depth. An evacuated glass sampling tube is then lowered down the penetration rods where it makes contact with the filter via a hypodermic needle and draws a pore fluid sample.
An investigation of the system was carried out at a number of sites contaminated by leaking underground gasoline storage tanks. Ground water samples obtained using the BAT system and adjacent monitoring wells were analyzed for volatile organic compounds (VOCs).
Because the BAT system is an in situ penetration device with a small filter length, it is possible to determine variations in contaminant concentration with depth. BAT samples in general exhibited higher recovery of VOCs than did bailer samples from adjacent monitoring wells screened over large intervals.
Much higher levels of VOCs were recovered when the probe was used with its 316 stainless steel filter than when using the high-density polyethylene (HDPE) filter. Significant sorption apparently occurred on the latter filter.
Because the BAT sample tubes are sealed and remain a closed system, the in situ water pressure is maintained. No significant loss of VOCs was found in sampling tubes containing headspace. Samples from the upper tube in the cascaded setup with headspace recovered levels of VOCs as high, or in a few cases higher, than the lower, no-headspace tubes. 相似文献
An investigation of the system was carried out at a number of sites contaminated by leaking underground gasoline storage tanks. Ground water samples obtained using the BAT system and adjacent monitoring wells were analyzed for volatile organic compounds (VOCs).
Because the BAT system is an in situ penetration device with a small filter length, it is possible to determine variations in contaminant concentration with depth. BAT samples in general exhibited higher recovery of VOCs than did bailer samples from adjacent monitoring wells screened over large intervals.
Much higher levels of VOCs were recovered when the probe was used with its 316 stainless steel filter than when using the high-density polyethylene (HDPE) filter. Significant sorption apparently occurred on the latter filter.
Because the BAT sample tubes are sealed and remain a closed system, the in situ water pressure is maintained. No significant loss of VOCs was found in sampling tubes containing headspace. Samples from the upper tube in the cascaded setup with headspace recovered levels of VOCs as high, or in a few cases higher, than the lower, no-headspace tubes. 相似文献
4.
Variations in concentrations of trichloroethylene and related compounds in ground water obtained from seven ground water samplers were used to compare the performance of three submersible pumps, a centrifugal pump, two peristaltic pumps, and a bailer. Two- and 4-inch diameter submersible pumps and a centrifugal pump produced samples whose trichloroethylene concentrations, on the average, did not differ significantly from each other. Ground water samples collected by using a peristaltic pump and silicone tubing had significantly lower trichloroethylene concentrations than samples from the submersible pumps. Concentrations of 1,2-dichloroethylene and trichloroethylene in ground water samples collected by using a bailer were indistinguishable from those in samples taken by a submersible pump when the concentrations were as much as 96 and 76 micrograms per liter, respectively, but were 15 and 12 percent lower when concentrations were as low as 29 and 23 micrograms per liter, respectively. Tests of different configurations of sampler placement in observation wells indicate that pump placement, rate of pumping, duration of pumping, and the uniformity of the vertical and lateral distribution of trichloroethylene in ground water near the well screen have a potentially significant influence on trichloroethylene concentrations in ground water samples and that these factors can have a greater effect than the type of sampler used. 相似文献
5.
Cone penetrometer tests and HydroPunch® sampling were used to define the extent of volatile organic compounds in ground water. The investigation indicated that the combination of these techniques is effective for obtaining ground water samples for preliminary plume definition. HydroPunch samples can be collected in unconsolidated sediments and the analytical results obtained from these samples are comparable to those obtained from adjacent monitoring wells. This sampling method is a rapid and cost-effective screening technique for characterizing the extent of contaminant plumes in soft sediment environments. Use of this screening technique allowed monitoring wells to be located at the plume boundary, thereby reducing the number of wells installed and the overall cost of the plume definition program. 相似文献
6.
Lawrence Livermore National Laboratory (LLNL) uses a cost-effective sampling (CES) methodology to evaluate and review ground water contaminant data and optimize the site's ground water monitoring plan. The CES methodology is part of LLNL's regulatory approved compliance monitoring plan (Lamarre et al. 1996). It allows LLNL to adjust the ground water sampling plan every quarter in response to changing conditions at the site. Since the use of the CES methodology has been approved by the appropriate regulatory agencies, such adjustments do not need additional regulatory approval. This permits LLNL to respond more quickly to changing conditions. The CES methodology bases the sampling frequency for each location on trend, variability, and magnitude statistics describing the contaminants at that location, and on the input of the technical staff (hydrologists, chemists, statisticians, and project leaders). After initial setup is complete, each application of CES takes only a few days for as many as 400 wells. Effective use of the CES methodology requires sufficient data, an understanding of contaminant transport at the site, and an adequate number of monitoring wells downgradient of the contamination. The initial implementation of CES at LLNL in 1992 produced a 40% reduction in the required number of annual routine ground water samples at LLNL. This has saved LLNL $390,000 annually in sampling, analysis, and data management costs. 相似文献
7.
The 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 pollutant. 相似文献
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 pollutant. 相似文献
8.
Potential for Solute Retardation on Monitoring Well Sand Packs and Its Effect on Purging Requirements for Ground Water Sampling 总被引：1，自引：0，他引：1
Monitoring well sand packs are theoretically capable of retarding metal ions and organic contaminants. If this retardation does indeed occur it may have a significant effect on the purging requirements of newly installed monitoring wells. Calculations based on mass balance and retardation concepts demonstrate that if common guidelines for well purging are followed, contaminants may not be detected or may be detected in lower concentrations than are actually present in the ground water. This problem is greatest in relatively shallow wells installed in low to moderate permeability materials. In most cases, the effect of solute retardation in the sand pack can be avoided simply by additional purging prior to the first sampling of the monitoring well. Common purging guidelines can then be applied to subsequent samplings. The methodology outlined in this paper can be used to calculate the purging requirements of existing monitoring wells or it may be applied to alternative monitoring well designs to test which will require the smallest volume of purged water. 相似文献
9.
Bert Smith Donald Siegel Charles Neslund Charles Carter 《Ground Water Monitoring & Remediation》2014,34(4):102-111
We report the results of two independent laboratory investigations to evaluate total and leachable concentrations of glycols, glycol ethers, phenol, and other compounds in representative Type I and Type I/II Portland cement products that United States Environmental Protection Agency (EPA), The American Society of Testing and Materials (ASTM) and others recommend as annular sealants in monitoring well completions. Water well drillers also use these cements in their well completions. The EPA has included some of these compounds for analysis in their National Hydraulic Fracturing Study to evaluate the effects of hydraulic fracturing on ground‐ and surface water resources. During any contaminant investigation, materials used in monitoring or water well drilling, completion, development, and sampling must be free of the chemicals being targeted by the regulatory agency. Three of five bulk cement products we tested contained part per million (ppm) (mg/kg) concentrations of diethylene glycol, ethylene glycol, tetraethylene glycol, and triethylene glycol; chemicals added as grinding aids during manufacture. Some cements also contained ppb (µg/kg) concentrations of benzoic acid, phenols, propylene glycol, and 2‐butoxyethanol. Leaching of cured cement samples in water produced ppm (mg/L) concentrations of glycols in the supernatant. These results show that cured cements in monitoring or water wells can contaminate groundwater samples with glycols and phenol. Our findings should help prevent future sample bias and false positives when testing for glycol compounds and phenol in groundwater samples from monitoring or water wells and highlight the need to test materials or products used in monitoring or water well drilling, completions, development, and sampling to avoid false positives when sampling and analyzing for less common analytical constituents. 相似文献
10.
Joel M. Hubbell Thomas R. Wood Brian Higgs Allan H. Wylie Deborah L. McElroy 《Ground Water Monitoring & Remediation》1998,18(3):151-157
Waste disposal sites with volatile organic compounds (VOCs) frequently contain contaminants that are present in both the ground water and vadose zone. Vertical sampling is useful where transport of VOCs in the vadose zone may effect ground water and where steep vertical gradients in chemical concentrations are anticipated. Designs for combination ground water and gas sampling wells place the tubing inside the casing with the sample port penetrating the casing for sampling. This physically interferes with pump or sampler placement. This paper describes a well design that combines a ground water well with gas sampling ports by attaching the gas sampling tubing and ports to the exterior of the casing. Placement of the tubing on the exterior of the casing allows exact definition of gas port depth, reduces physical interference between the various monitoring equipment, and allows simultaneous remediation and monitoring in a single well. The usefulness and versatility of this design was demonstrated at the Idaho National Engineering and Environmental Laboratory (INEEL) with the installation of seven wells with 53 gas ports, in a geologic formation consisting of deep basalt with sedimentary interbeds at depths from 7.2 to 178 m below land surface. The INEEL combination well design is easy to construct, install, and operate. 相似文献
11.
Timothy B. Spruill 《Ground Water Monitoring & Remediation》1988,8(3):76-82
Water samples collected from 26 sites at an abandoned oil refinery in south-central Kansas were analyzed for total organic carbon (TOC) and specific volatile and semivolatile organic compounds by gas-chromatography/mass-spectrometric methods. Results from a Spearman-rho correlation analysis between TOC concentration and the number of compounds (correlation coefficient = 0.71) and TOC concentration and total concentration of compounds identified (correlation coefficient = 0.83) indicate correlations significant at the 0.01 level.
Although TOC data alone would not be sufficient to evaluate hazards posed by oil-refinery wastes, results of the correlation analysis performed using data collected from the site in Kansas indicate that TOC data can be used effectively to delineate petroleum-related ground water contamination and to help identify sources of ground water contaminants. TOC data collected from a large number of temporary sampling points during the initial phases of an investigation will provide an estimate of the extent of hydrocarbon contamination and allow placement of monitoring wells and more detailed sampling in appropriate areas. 相似文献
Although TOC data alone would not be sufficient to evaluate hazards posed by oil-refinery wastes, results of the correlation analysis performed using data collected from the site in Kansas indicate that TOC data can be used effectively to delineate petroleum-related ground water contamination and to help identify sources of ground water contaminants. TOC data collected from a large number of temporary sampling points during the initial phases of an investigation will provide an estimate of the extent of hydrocarbon contamination and allow placement of monitoring wells and more detailed sampling in appropriate areas. 相似文献
12.
The progressive packer/zone sampling method was used to identify the bottom of a plume of volatile organic compounds (VOCs) in the parts-per-million (ppm) range using one well in each of three separate locations. The method involves progressively drilling a 20-foot length of borehole through casing, setting an inflatable packer at the top of the drilled zone, purging the zone of three volumes of water using the airlift method, sampling the zone in situ through the packer string using a bailer, then repeating the procedure.
A plume consisting of chlorinated VOCs, alcohols, and vinyl chloride occurs in a low-yielding fractured bedrock aquifer located in the Passaic Formation at a site in central New Jersey. The thickness of the plume in total VOC concentrations exceeding 1 ppm was determined using the progressive packer/zone sampling method to a depth of 200 feet. The first borehole was completed as a monitoring well in the "hottest" zone encountered during testing. Additional wells were then clustered with this exploratory well to delineate the plume in the parts-per-billion (ppb) range. Cross contamination from previously sampled zones was not a problem as long as total VOCs in the ppm range were targeted and the sample interval was properly purged.
Instead of using a multiple well cluster consisting of an indefinite number of wells to determine the bulk thickness of a plume at a specific location, information from one borehole may suffice during the exploratory phase. Costs to the client and cross contamination potential to the aquifer can be minimized by limiting the number of boreholes needed for vertical delineation. 相似文献
A plume consisting of chlorinated VOCs, alcohols, and vinyl chloride occurs in a low-yielding fractured bedrock aquifer located in the Passaic Formation at a site in central New Jersey. The thickness of the plume in total VOC concentrations exceeding 1 ppm was determined using the progressive packer/zone sampling method to a depth of 200 feet. The first borehole was completed as a monitoring well in the "hottest" zone encountered during testing. Additional wells were then clustered with this exploratory well to delineate the plume in the parts-per-billion (ppb) range. Cross contamination from previously sampled zones was not a problem as long as total VOCs in the ppm range were targeted and the sample interval was properly purged.
Instead of using a multiple well cluster consisting of an indefinite number of wells to determine the bulk thickness of a plume at a specific location, information from one borehole may suffice during the exploratory phase. Costs to the client and cross contamination potential to the aquifer can be minimized by limiting the number of boreholes needed for vertical delineation. 相似文献
13.
《Ground Water Monitoring & Remediation》1985,5(2):75-82
Seepage from tailings ponds associated with an active uranium mill in Utah has resulted in contamination of ground water contained in the Dakota-Burro Canyon Formation. This aquifer is used in the area as a supply for domestic and industrial wells.
Results of very low-frequency electromagnetic surveys and ground water quality investigations at the site indicated that the flow of ground water and contaminants is primarily fracture-controlled. Pumping tests were conducted to determine the hydraulic characteristics of the fractured system. The extent of contaminant migration was then determined using an analytical model of transport in fractured aquifers.
Based on these investigations, a plan was designed to control future and remediate past ground water contamination. This plan consists of pumping from a single well intersecting the main fracture that transports contaminants off the site. The effectiveness of the plan was analytically modeled, taking account of the anisotropy of the ground water system. Subsequent monitoring of water levels in the area indicates that the plan has been effective since its inception in November 1983. 相似文献
Results of very low-frequency electromagnetic surveys and ground water quality investigations at the site indicated that the flow of ground water and contaminants is primarily fracture-controlled. Pumping tests were conducted to determine the hydraulic characteristics of the fractured system. The extent of contaminant migration was then determined using an analytical model of transport in fractured aquifers.
Based on these investigations, a plan was designed to control future and remediate past ground water contamination. This plan consists of pumping from a single well intersecting the main fracture that transports contaminants off the site. The effectiveness of the plan was analytically modeled, taking account of the anisotropy of the ground water system. Subsequent monitoring of water levels in the area indicates that the plan has been effective since its inception in November 1983. 相似文献
14.
Pesticides in Nebraska's Ground Water 总被引：1，自引：0，他引：1
《Ground Water Monitoring & Remediation》1989,9(4):126-133
More 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. 相似文献
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. 相似文献
15.
《Ground Water Monitoring & Remediation》1988,8(1):51-59
Determination of the nature, extent, and rate of off-site chemical migration are common objectives of hazardous waste site investigations. Chemical analyses of water samples from monitoring wells and measurements of hydraulic head and hydraulic conductivity provide the basis for making these determinations. Accurate site assessment, therefore, depends upon the appropriate monitoring well design and sampling and testing procedures.
During the course of remedial investigations in Niagara Falls, New York, it has been necessary to evaluate the ground water quality and hydraulic characteristics of 5- to 30-feet thick overburden formations. Many of the monitoring wells completed to these formations consist of a partially penetrating screen (5 feet at the base of the formation) with a fully penetrating sandpack. Questions regarding how this well design influences the source of sampled ground water and hydraulic tests were examined using an extremely fine axisymmetric grid with SATURN, a two-dimensional, finite-element ground water model, and a particle tracking post-processor.
A discrete sensitivity analysis was made to determine how flow patterns induced by pumping at 1 gpm are affected by: different screen and sandpack configurations, the ratio of sandpack to formation hydraulic conductivities, heterogeneity, anisotropy, and sandpack thickness. The simulations show that the source (and chemistry given a non-uniform chemical distribution) of ground water sampled will vary considerably depending on a number of factors. Analysis of simulated drawdowns in the monitoring well during purging shows that calculated transmissivities for the range of well designs and conditions modeled will be accurate to within one-half order of magnitude. 相似文献
During the course of remedial investigations in Niagara Falls, New York, it has been necessary to evaluate the ground water quality and hydraulic characteristics of 5- to 30-feet thick overburden formations. Many of the monitoring wells completed to these formations consist of a partially penetrating screen (5 feet at the base of the formation) with a fully penetrating sandpack. Questions regarding how this well design influences the source of sampled ground water and hydraulic tests were examined using an extremely fine axisymmetric grid with SATURN, a two-dimensional, finite-element ground water model, and a particle tracking post-processor.
A discrete sensitivity analysis was made to determine how flow patterns induced by pumping at 1 gpm are affected by: different screen and sandpack configurations, the ratio of sandpack to formation hydraulic conductivities, heterogeneity, anisotropy, and sandpack thickness. The simulations show that the source (and chemistry given a non-uniform chemical distribution) of ground water sampled will vary considerably depending on a number of factors. Analysis of simulated drawdowns in the monitoring well during purging shows that calculated transmissivities for the range of well designs and conditions modeled will be accurate to within one-half order of magnitude. 相似文献
16.
A six year field experiment has shown that a sand-bentonite mixture used to seal monitoring wells in aquitards contributes solutes to the ground water sampled from these wells. Monitoring wells were installed at field sites with hydraulic conductivity (K) ranging from 5 × 10 -9 m/s to 3 × 1011 m/s. In most cases the boreholes remained dry during installation which allowed the placement of a dry powdered bentonite/sand mixture tagged with potassium bromide (KBr) to seal and separate sampling points. Over six years, wells were sampled periodically and ground-water samples were analyzed for Br and Cl and other major ions. Typical Br results ranged from 10 mg/1 to 35 mg/1 in the first 700 days, as compared to an estimated initial concentration in the seal material of about 75 mg/1. After six years the bromide concentrations had decreased to between 3 mg/1 and 5 mg/1. The total mass of Br removed in six years is less than 50% of that placed; therefore the contamination effects, although considerably diminished, persist. The trends of Br, Cl, Na, and SO4 indicate that varying degrees of contamination occur. These data show that the materials used to seal monitoring wells in aquitards can have a significant and long-lasting impact on the chemistry of the water in the wells. 相似文献
17.
Suzanne Lesage Richard E. Jackson Mark Priddle Paul Beck Ken G. Raven 《Ground Water Monitoring & Remediation》1991,11(1):151-159
The objective of this study was to assess the possible impact of deep well disposal operations, conducted between 1958 and 1974, on the ground water quality in a shallow fresh water aquifer beneath Sarnia, Ontario, Canada. Because of the breakout of formation fluids in Sarnia and Port Huron, Michigan, in the early 1970s, it had been hypothesized that liquid waste from the disposal zone in bedrock had leaked through numerous abandoned oil, gas, and salt wells in the area up to the shallow fresh water aquifer and from there to the surface.
A monitoring well network of 29 5cm (2 inch) diameter piezometers was established in the thin sand and shale aquifer system, which exists between 30 and 70m (100 and 230 feet) below ground surface. In addition, a 300m (1000 foot) deep borehole was drilled and instrumented with a Westbay multilevel casing, which permitted sampling of the disposal zone.
Ground water samples from the shallow monitoring wells and the Westbay multilevel casing were analyzed for volatiles by GC/MS. Those volatile aromatics that were conspicuously present in the deep disposal zone, e.g., ethyl toluenes and trimethyl benzene, were not detected in the shallow monitoring wells. Thus, if contaminants from the disposal zone did indeed migrate to the shallow aquifer, contamination was not widespread and probably consisted mostly of displaced chloride-rich formation waters. 相似文献
A monitoring well network of 29 5cm (2 inch) diameter piezometers was established in the thin sand and shale aquifer system, which exists between 30 and 70m (100 and 230 feet) below ground surface. In addition, a 300m (1000 foot) deep borehole was drilled and instrumented with a Westbay multilevel casing, which permitted sampling of the disposal zone.
Ground water samples from the shallow monitoring wells and the Westbay multilevel casing were analyzed for volatiles by GC/MS. Those volatile aromatics that were conspicuously present in the deep disposal zone, e.g., ethyl toluenes and trimethyl benzene, were not detected in the shallow monitoring wells. Thus, if contaminants from the disposal zone did indeed migrate to the shallow aquifer, contamination was not widespread and probably consisted mostly of displaced chloride-rich formation waters. 相似文献
18.
《Ground Water Monitoring & Remediation》2000,20(1):120-126
Ground water at the Norman Landfill Research Site is contaminated by a leachate plume emanating from a closed, unlined landfill formerly operated by the city of Norman, Oklahoma, Ground water contaminated by the leachate plume is known to be elevated in the concentration of many, organic and inorganic constituents. Specific conductance, alkalinity, chloride, dissolved organic carbon, boron, sodium, strontium, and deuterium in ground water are considered to be indicators of the leachate plume at this site.
Leaf samples of broad-leafed cottonwood, Populus deltoides , were collected from 57 sites around the closed landfill. Cottonwood, a phreatophyte or "well plant," functions as a & surrogate well and serves as a ground water quality sampler. The leaf samples were combusted to ash and analyzed by instrumental neutron activation for 35 elements and by prompt-gamma instrumental neutron activation, for boron. A monitoring well was located within a few meters of a sampled cottonwood tree at 15 of the 57 sites, and ground water samples were collected from these monitoring wells simultaneously with a leaf sample. The chemical analyses of the ground water and leaf samples from these 15 sites indicated that boron, bromine, sodium, and strontium concentrations in leaves were significantly correlated with leachate indicator constituents in ground water. A point-plot map of selected percentiles indicated high concentrations of boron, bromine, and sodium in leaf ash from sites downgradient of the most recent landfill and from older landfills nearby.
Data from leaf analysis greatly extended the known areal extent of the leachate plume previously determined from a network of monitoring wells and geophysical surveys. This phytosgeochemical study provided a cost-effective method for assessing the extent of a leachate plume from an old landfill. Such a method may be useful as a preliminary sampling tool to guide the design of hydrogeochemical and geophysical studies. 相似文献
Leaf samples of broad-leafed cottonwood, Populus deltoides , were collected from 57 sites around the closed landfill. Cottonwood, a phreatophyte or "well plant," functions as a & surrogate well and serves as a ground water quality sampler. The leaf samples were combusted to ash and analyzed by instrumental neutron activation for 35 elements and by prompt-gamma instrumental neutron activation, for boron. A monitoring well was located within a few meters of a sampled cottonwood tree at 15 of the 57 sites, and ground water samples were collected from these monitoring wells simultaneously with a leaf sample. The chemical analyses of the ground water and leaf samples from these 15 sites indicated that boron, bromine, sodium, and strontium concentrations in leaves were significantly correlated with leachate indicator constituents in ground water. A point-plot map of selected percentiles indicated high concentrations of boron, bromine, and sodium in leaf ash from sites downgradient of the most recent landfill and from older landfills nearby.
Data from leaf analysis greatly extended the known areal extent of the leachate plume previously determined from a network of monitoring wells and geophysical surveys. This phytosgeochemical study provided a cost-effective method for assessing the extent of a leachate plume from an old landfill. Such a method may be useful as a preliminary sampling tool to guide the design of hydrogeochemical and geophysical studies. 相似文献
19.
Small Purge Method to Sample Vapor from Groundwater Monitoring Wells Screened Across the Water Table 
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下载免费PDF全文 Groundwater monitoring wells are present at most hydrocarbon release sites that are being assessed for cleanup. If screened across the vadose zone, these wells provide an opportunity to collect vapor samples that can be used in the evaluation of vapor movement and biodegradation processes occurring at such sites. This paper presents a low purge volume method (modified after that developed by the U.S. EPA) for sampling vapor from monitoring wells that is easy to implement and can provide an assessment of the soil gas total petroleum hydrocarbon (TPH) and O2 concentrations at the base of the vadose zone. As a result, the small purge method allows for sampling of vapor from monitoring wells to support petroleum vapor intrusion (PVI) risk assessment. The small purge volume method was field tested at the Hal's service station site in Green River, Utah. This site is well‐known for numerous soil gas measurements containing high O2 and high TPH vapor concentrations in the same samples which is inconsistent with well‐accepted biodegradation models for the vapor pathway. Using the low purge volume method, monitoring wells were sampled over, upgradient, and downgradient of the light nonaqueous phase liquid (LNAPL) footprint. Results from our testing at Hal's show that vapor from monitoring wells over LNAPL contained very low O2 and high TPH concentrations. In contrast, vapor from monitoring wells not over LNAPL contained high O2 and low TPH concentrations. The results of this study show that a low purge volume method is consistent with biodegradation models especially for sampling at sites where low permeability soils exist in and around a LNAPL source zone. 相似文献
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The screened auger is a laser-slotted, hollow-stem auger through which a representative sample of ground water is pumped from an aquifer and tested for water-quality parameters by appropriate field-screening methods. Screened auger sampling can be applied to ground water quality remedial investigations, providing:(1) a mechanism for determining a monitoring well's optimal screen placement in a contaminant plume; and (2) data to define the three-dimensional configuration of the contaminant plume.
Screened auger sampling has provided an efficient method for investigating hexavalent chromium and volatile organic compound contamination in two sandy aquifers in Cadillac, Michigan. The aquifers approach 200 feet in thickness and more than 1 square mile in area. A series of screened auger borings and monitoring wells was installed, and ground water was collected at 10-foot intervals as the boreholes were advanced to define the horizontal and vertical distribution of the contaminant plumes. The ability of the screened auger to obtain representative ground water samples was supported by the statistical comparison of field screening results and subsequent laboratory analysis of ground water from installed monitoring wells. 相似文献
Screened auger sampling has provided an efficient method for investigating hexavalent chromium and volatile organic compound contamination in two sandy aquifers in Cadillac, Michigan. The aquifers approach 200 feet in thickness and more than 1 square mile in area. A series of screened auger borings and monitoring wells was installed, and ground water was collected at 10-foot intervals as the boreholes were advanced to define the horizontal and vertical distribution of the contaminant plumes. The ability of the screened auger to obtain representative ground water samples was supported by the statistical comparison of field screening results and subsequent laboratory analysis of ground water from installed monitoring wells. 相似文献