Development of Radon-222 as a Natural Tracer for Monitoring the Remediation of NAPL Contamination in the Subsurface. 1998 Annual Progress Report PDF Download
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Author: Publisher: ISBN: Category : Languages : en Pages : 3
Book Description
The objective of this research is to develop a unique method of using naturally occurring radon-222 as a tracer for locating and quantitatively describing the presence of subsurface NAPL contamination. The research will evaluate using radon as an inexpensive, yet highly accurate, means of detecting NAPL contamination and assessing the effectiveness of NAPL remediation. Laboratory, field, and modeling studies are being performed to evaluate this technique, and to develop methods for its successful implementation in practice. This report summarizes work that has been accomplished after 1-year of a 3-year project. The research to date has included radon tracer tests in physical aquifer models (PAMs) and field studies at Site 300 of the Lawrence Livermore National Laboratory, CA, and Site 100D at Hanford DOE Facility, WA. The PAM tests have evaluated the ability of radon as a tracer to monitor the remediation of TCE NAPL contamination using surfactant treatment, and oxidation with permanganate. The surfactant tests were performed in collaboration with Dr. Jack Istok and Dr. Jennifer Field and their EMSP project ''In-situ, Field-Scale Evaluation of Surfactant Enhanced DNAPL Recovery Using a Single-Well-Push-Pull Test.'''' This collaboration enabled the EMSP radon project to make rapid progress. The PAM surfactant tests were performed in a radial flow geometry to simulate the push-pull-method that is being developed for surfactant field tests. The radon tests were easily incorporated into these experiments, since they simply rely on measuring the natural radon present in the subsurface fluids. Two types of radon tests were performed: (1) static tests where radon was permitted to build-up to steady-state concentrations in the pore fluids and the groundwater concentrations were monitored, and (2) dynamic tests were the radon response during push-pull surfactant tests was measured. Both methods were found to be useful in determining how NAPL remediation was progressing.
Author: Publisher: ISBN: Category : Languages : en Pages : 3
Book Description
The objective of this research is to develop a unique method of using naturally occurring radon-222 as a tracer for locating and quantitatively describing the presence of subsurface NAPL contamination. The research will evaluate using radon as an inexpensive, yet highly accurate, means of detecting NAPL contamination and assessing the effectiveness of NAPL remediation. Laboratory, field, and modeling studies are being performed to evaluate this technique, and to develop methods for its successful implementation in practice. This report summarizes work that has been accomplished after 1-year of a 3-year project. The research to date has included radon tracer tests in physical aquifer models (PAMs) and field studies at Site 300 of the Lawrence Livermore National Laboratory, CA, and Site 100D at Hanford DOE Facility, WA. The PAM tests have evaluated the ability of radon as a tracer to monitor the remediation of TCE NAPL contamination using surfactant treatment, and oxidation with permanganate. The surfactant tests were performed in collaboration with Dr. Jack Istok and Dr. Jennifer Field and their EMSP project ''In-situ, Field-Scale Evaluation of Surfactant Enhanced DNAPL Recovery Using a Single-Well-Push-Pull Test.'''' This collaboration enabled the EMSP radon project to make rapid progress. The PAM surfactant tests were performed in a radial flow geometry to simulate the push-pull-method that is being developed for surfactant field tests. The radon tests were easily incorporated into these experiments, since they simply rely on measuring the natural radon present in the subsurface fluids. Two types of radon tests were performed: (1) static tests where radon was permitted to build-up to steady-state concentrations in the pore fluids and the groundwater concentrations were monitored, and (2) dynamic tests were the radon response during push-pull surfactant tests was measured. Both methods were found to be useful in determining how NAPL remediation was progressing.
Author: Publisher: ISBN: Category : Languages : en Pages : 5
Book Description
The objective of this research is to develop a unique method for using naturally occurring radon-222 as an inexpensive partitioning tracer for locating and quantitatifying nonaqueous phase liquid (NAPL) contamination in the subsurface, and assessing the effectiveness of NAPL remediation. Laboratory, field, and modeling studies are being performed to evaluate this technique, and to develop methods for its successful implementation in practice.
Author: Publisher: ISBN: Category : Languages : en Pages : 98
Book Description
Nonaqueous phase liquids (NAPL), including chlorinated solvents, aromatic hydrocarbons, and other volatile organic chemicals (VOC), are common contaminants at Department of Defense (DoD) and other federal and non-federal sites. Residual or pooled NAPL contamination provides a long-term source of contamination as it slowly dissolves into groundwater. A major obstacle preventing cost-effective soil and groundwater cleanup at many DoD sites is the current inability to accurately and inexpensively locate and quantify NAPL contamination. This final report describes the use of naturally occurring radon-222 (Rn) as a partitioning tracer for locating and quantifying NAPL contamination in the subsurface and for monitoring changes in NAPL quantities resulting from remediation activities. Radon-222 possesses unique physical properties that make it a useful natural partitioning tracer for detecting and quantifying NAPL. Rn is produced in the subsurface by the continuous decay of naturally occurring radium-226. In the absence of NAPL contamination, the aqueous Rn concentration quickly reaches a site-specific equilibrium value determined by the mineralogy and porosity of the geologic formation. In the presence of NAPL, however, the Rn concentration is substantially reduced due to partitioning of Rn into the organic NAPL phase. Moreover, the reduction in Rn concentration of groundwater in contact with a NAPL phase is quantitatively correlated with the quantity of NAPL present, as described by simple equilibrium models. Thus, the method is based on measuring Rn in groundwater samples from existing monitoring wells.
Author: Publisher: ISBN: Category : Languages : en Pages : 5
Book Description
Naturally occurring 222-radon in ground water can potentially be used as an in situ partitioning tracer to characterize dense nonaqueous phase liquid (DNAPL) saturations. The static method involves comparing radon concentrations in water samples from DNAPL-contaminated and non-contaminated portions of an aquifer. During a push-pull test, a known volume of test solution (radon-free water containing a conservation tracer) is first injected (''pushed'') into a well; flow is then reversed and the test solution/groundwater mixture is extracted (''pulled'') from the same well. In the presence of NAPL radon transport is retarded relative to the conservative tracer. Assuming linear equilibrium partitioning, retardation factors for radon can be used to estimate NAPL saturations. The utility of this methodology was evaluated in laboratory and field settings.
Author: Publisher: ISBN: Category : Languages : en Pages : 5
Book Description
Dense non-aqueous phase liquids (DNAPLs) such as trichloroethene (TCE) and perchloroethene (PCE) present long-term challenges in terms of quantification in the subsurface at many DOE facilities. Over the past year we have continued investigating a potentially lower cost method for quantifying DNAPLs in the subsurface using naturally occurring, in situ dissolved radon as a partitioning tracer. Radon can be used as a partitioning tracer in both static (i.e., no flow) and dynamic methodologies (Semprini et al., 1993; Semprini et al., 1998; Semprini et al., 2000). The static radon method involves obtaining radon samples from DNAPL-contaminated and non-contaminated portions of the aquifer and using the change in radon concentrations to locate and quantify DNAPL saturation in the aquifer. The dynamic radon method incorporates single-well injection withdrawal (i.e., push-pull) tests to estimate radon retardation and DNAPL saturation. These methods have the potential to provide a robust method for DNAPL saturation quantification while decreasing the costs associated with these activities.
Author: Sarayu Gottipati Publisher: ISBN: Category : Soil remediation Languages : en Pages : 252
Book Description
Persistence of Non aqueous phase liquids (NAPLs) in the subsurface at residual saturations eventually contributes to undesirable groundwater contamination. Proper characterization of subsurface NAPL, its location, composition and distribution, is essential for the chosen remediation technology to be effective. It is also desirable to assess the performance of remedial actions at NAPL-contaminated sites in order to verify the technoeconomic viability of the selected method. The unique properties of radon-222 gas make it a good indicator for organic phase liquids. It is ubiquitous in the subsurface, chemically inert, radioactive, and most importantly, partitions into NAPLs. This research explores the practicality of using radon to indirectly monitor the progress of NAPL remediation efforts. The effectiveness of surfactant flushing in remediating NAPL contamination was also studied in the process. Preliminary studies were conducted using micro-columns to evaluate the efficiency of the surfactant selected for the study, triton. These studies show that triton is more effective at higher concentrations in solubilizing residual soltrol and its solubilizing capacity is greatly enhanced after batch equilibration. These observations suggest that surfactant solubilization of NAPLs is rate-limited rather than instantaneous. These studies also indicate the adverse effect of aged NAPL on surfactant solubilizing capacity. Two independent methods, total organic carbon analysis and HDPE strip test, were also designed for analyzing the aqueous and sand samples and estimating the level of cleanup achieved. Since triton proved to be effective in micro-column studies, the remediation of the soil columns was performed by flushing triton through the columns in a sequential batch mode. The soil columns employed in the study had been previously packed and used by Hopkins (1994). The influence of the decrease in residual soltrol saturations on breakthrough of radon was observed. The gradual cleanup of columns at various initial residual soltrol saturations (1.0%, 5.0%, and 8.0%) through surfactant flushing was well reflected by radon. The aqueous radon concentrations increased and the retardation of radon lessened as residual soltrol was removed from the columns. The linear equilibrium partitioning model of radon was used to estimate the initial residual NAPL saturation in each column and the subsequent saturations as the remediation proceeded. The saturation estimates were based on retardation factors obtained from maximum aqueous radon concentrations and breakthrough of radon. These estimates correlated fairly well with those based on TOC analyses and HDPE strip tests, supporting radon's capability of detecting and quantifying NAPLs, and monitoring the progress of NAPL remediation. The results of this study demonstrate the potential of radon as a tracer for evaluating the performance of NAPL remediation techniques. This study also substantiates the ability of surfactants to enhance NAPL recovery from subsurface. However, clogging problems have been encountered, which are believed to be caused by surfactant micelles, while sampling columns. Hence, careful selection of appropriate surfactant, among other criteria, is essential to get maximum benefits of surfactant-enhanced NAPL remediation technology.
Author: Mark Baskaran Publisher: Springer ISBN: 3319213296 Category : Science Languages : en Pages : 276
Book Description
This book reviews all the major research accomplishments and summarizes the different applications of radon. It serves as a solid reference book for researchers who are interested in the U-series radionuclides and noble gases as tracers and chronometers. Radon has been widely utilized as a powerful tracer to quantify a number of processes that include gas exchange rates between air and water, submarine groundwater discharge in coastal waters, water exchange between rivers and lakes, ocean circulation, hydrocarbon and uranium exploration. It is also used as an atmospheric tracer for the identification and quantification of air masses and as a tool for earthquake prediction, etc. A significant portion of the book presents state-of-the knowledge on indoor-radon-related health issues. Applications of the decay-series of Rn-222 are presented in a chapter. It serves as a reference and a state-of-the-art resource for researchers who want to learn the different applications of radon in Earth systems.
Author: National Research Council Publisher: National Academies Press ISBN: 0309278139 Category : Nature Languages : en Pages : 423
Book Description
Across the United States, thousands of hazardous waste sites are contaminated with chemicals that prevent the underlying groundwater from meeting drinking water standards. These include Superfund sites and other facilities that handle and dispose of hazardous waste, active and inactive dry cleaners, and leaking underground storage tanks; many are at federal facilities such as military installations. While many sites have been closed over the past 30 years through cleanup programs run by the U.S. Department of Defense, the U.S. EPA, and other state and federal agencies, the remaining caseload is much more difficult to address because the nature of the contamination and subsurface conditions make it difficult to achieve drinking water standards in the affected groundwater. Alternatives for Managing the Nation's Complex Contaminated Groundwater Sites estimates that at least 126,000 sites across the U.S. still have contaminated groundwater, and their closure is expected to cost at least $110 billion to $127 billion. About 10 percent of these sites are considered "complex," meaning restoration is unlikely to be achieved in the next 50 to 100 years due to technological limitations. At sites where contaminant concentrations have plateaued at levels above cleanup goals despite active efforts, the report recommends evaluating whether the sites should transition to long-term management, where risks would be monitored and harmful exposures prevented, but at reduced costs.
Author: Publisher: ISBN: Category : Arsenic Languages : en Pages : 124
Book Description
V.3 ... consists of individual chapters that describe 1) the conceptual background for radionuclides, including tritium, radon, strontium, technetium, uranium, iodine, radium, thorium, cesium, plutonium-americium and 2) data requirements to be met during site characterization.
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