Integration of Raman Spectroscopy and Cone Penetration Technology Characterize Chlorinated Hydrocarbon Contaminant Plumes

The goal of the project was the development and integration of a Raman spectroscopy unit with a Cone Penetration Technologies (CPT) system for use in locating contamination below the ground surface

Characterization of DNAPL Using Fluorescence Techniques

Dense non aqueous phase liquid (DNAPL) contaminants, comprised of chlorinated aliphatic compounds, are a major source of groundwater contamination at the Savannah River Site (SRS). To successfully remediate a site contaminated by DNAPLs, it is imperative that the slowly dissolving, non-aqueous phase source be found and removed. There are few technologies that can successfully and consistently detect DNAPLs in the subsurface either directly or by inferred measurements. Because of the use of chlorinated solvents to remove petroleum-based cutting oils and lubricants at SRS (and other manufacturing sites) in degreasing operations, waste solvents may contain small amounts of the oils and lubricants. This mixture will fluoresce when excited by light of wavelengths capable of being transmitted over optical fiber. Samples of DNAPL from the A/M area of SRS were analyzed to assess the possibilities of contaminant detection by fluorescence spectroscopy. The DNAPL sample exhibited a strong, distinct fluorescent spectrum when exposed to an appropriate excitation wavelength. A cone penetrometer-based, laser induced fluorescent system may be capable of providing direct detection of DNAPLs in the subsurface based on these results

INDEPENDENT TECHNICAL REVIEW OF THE FOCUSED FEASIBILITY STUDY AND PROPOSED PLAN FOR DESIGNATED SOLID WASTE MANAGEMENT UNITS CONTRIBUTING TO THE SOUTHWEST GROUNDWATER PLUME AT THE PADUCAH GASEOUS DIFFUSION PLANT

The U. S. Department of Energy (DOE) is currently developing a Proposed Plan (PP) for remediation of designated sources of chlorinated solvents that contribute contamination to the Southwest (SW) Groundwater Plume at the Paducah Gaseous Diffusion Plant (PGDP), in Paducah, KY. The principal contaminants in the SW Plume are trichloroethene (TCE) and other volatile organic compounds (VOCs); these industrial solvents were used and disposed in various facilities and locations at PGDP. In the SW plume area, residual TCE sources are primarily in the fine-grained sediments of the Upper Continental Recharge System (UCRS), a partially saturated zone that delivers contaminants downward into the coarse-grained Regional Gravel Aquifer (RGA). The RGA serves as the significant lateral groundwater transport pathway for the plume. In the SW Plume area, the four main contributing TCE source units are: (1) Solid Waste Management Unit (SWMU) 1 / Oil Landfarm; (2) C-720 Building TCE Northeast Spill Site (SWMU 211A); (3) C-720 Building TCE Southeast Spill Site (SWMU 211B); and (4) C-747 Contaminated Burial Yard (SWMU 4). The PP presents the Preferred Alternatives for remediation of VOCs in the UCRS at the Oil Landfarm and the C-720 Building spill sites. The basis for the PP is documented in a Focused Feasibility Study (FFS) (DOE, 2011) and a Site Investigation Report (SI) (DOE, 2007). The SW plume is currently within the boundaries of PGDP (i.e., does not extend off-site). Nonetheless, reasonable mitigation of the multiple contaminant sources contributing to the SW plume is one of the necessary components identified in the PGDP End State Vision (DOE, 2005). Because of the importance of the proposed actions DOE assembled an Independent Technical Review (ITR) team to provide input and assistance in finalizing the PP

RECOMMENDATIONS FOR PHASE II VADOSE ZONE CHARACTERIZATION AND MONITORING AT THE E-AREA DISPOSAL SLIT TRENCHES AND MEGA-TRENCH

A Radiological Performance Assessment Maintenance Plan (SDW, 1997) was prepared in response to Recommendation 94-2 made by the Defense Nuclear Facility Board (DNFSB) and establishes a requirement for preparing and implementing the E-Area Monitoring Program (EMOP). Based on the results of a statistical analysis of the existing groundwater monitoring network at the Burial Ground and a review of alternative monitoring strategies, a vadose zone monitoring system (YZMS) was selected for the EMOP. The EMOP (SWD, 1998) was prepared in 1998 and describes a phased approach for implementation. The YZMS was designed to detect contamination before it reached the water table and includes collection of pore water samples from sediments above the water table and monitoring pore water pressure and water content of the unsaturated sediments that comprise the vadose zone. This information is then used to calculate the flux of contaminants for comparison with the requirements specified in the E-Area Performance Assessment. In 1999, Phase I of the EMOP was implemented by installation of advanced tensiometers, water content sensors, and vertical and angled lysimeters. In addition several cone penetrometer logs of resistivity and stress ratio were collected and shelby tube samples were collected for measurement of hydraulic properties. Results from Phase I of the EMOP show that the general strategy and techniques selected are adequate for monitoring moisture conditions and contaminant migration. Data from Phase I of the EMOP was used to prepare a numerical model of moisture flow beneath a typical disposal trench. The moisture contents, pore pressure, and flow patterns predicted by the model were compared with field data and used to improve the components of Phase II of the EMOP. Based on these data and the numerical analysis of moisture movement at a typical disposal trench, the objectives of the Phase II EMOP characterization and monitoring are: (1) Collect additional data on moisture release properties to minimize uncertainty in flux calculations; (2) Use neutron probe to measure moisture profile and validate water content sensors; (3) Calibrate neutron probe with site specific calibration curve; (4) Locate tensiometers to provide data useful for calculation of hydraulic gradient; and (5) Incorporate new data from EMOP in conceptual of moisture flow at disposal trenches to improve flux calculations. Meeting these objectives will provide the information necessary to determine compliance with the requirements of the E-Area Performance Assessment and protect groundwater resources

RECOMMENDATIONS FOR PHASE II VADOSE ZONE CHARACTERIZATION AND MONITORING AT THE E-AREA DISPOSAL SLIT TRENCHES AND MEGA-TRENCH

A Radiological Performance Assessment Maintenance Plan (SDW, 1997) was prepared in response to Recommendation 94-2 made by the Defense Nuclear Facility Board (DNFSB) and establishes a requirement for preparing and implementing the E-Area Monitoring Program (EMOP). Based on the results of a statistical analysis of the existing groundwater monitoring network at the Burial Ground and a review of alternative monitoring strategies, a vadose zone monitoring system (YZMS) was selected for the EMOP. The EMOP (SWD, 1998) was prepared in 1998 and describes a phased approach for implementation. The YZMS was designed to detect contamination before it reached the water table and includes collection of pore water samples from sediments above the water table and monitoring pore water pressure and water content of the unsaturated sediments that comprise the vadose zone. This information is then used to calculate the flux of contaminants for comparison with the requirements specified in the E-Area Performance Assessment. In 1999, Phase I of the EMOP was implemented by installation of advanced tensiometers, water content sensors, and vertical and angled lysimeters. In addition several cone penetrometer logs of resistivity and stress ratio were collected and shelby tube samples were collected for measurement of hydraulic properties. Results from Phase I of the EMOP show that the general strategy and techniques selected are adequate for monitoring moisture conditions and contaminant migration. Data from Phase I of the EMOP was used to prepare a numerical model of moisture flow beneath a typical disposal trench. The moisture contents, pore pressure, and flow patterns predicted by the model were compared with field data and used to improve the components of Phase II of the EMOP. Based on these data and the numerical analysis of moisture movement at a typical disposal trench, the objectives of the Phase II EMOP characterization and monitoring are: (1) Collect additional data on moisture release properties to minimize uncertainty in flux calculations; (2) Use neutron probe to measure moisture profile and validate water content sensors; (3) Calibrate neutron probe with site specific calibration curve; (4) Locate tensiometers to provide data useful for calculation of hydraulic gradient; and (5) Incorporate new data from EMOP in conceptual of moisture flow at disposal trenches to improve flux calculations. Meeting these objectives will provide the information necessary to determine compliance with the requirements of the E-Area Performance Assessment and protect groundwater resources

INDEPENDENT REVIEW OF THE X-701B GROUNDWATER REMEDY, PORTSMOUTH, OHIO: TECHNICAL EVALUATION AND RECOMMENDATIONS

The Department of Energy Portsmouth Paducah Project Office requested assistance from Department of Energy Office of Environmental Management (EM-22) to provide independent technical experts to evaluate past and ongoing remedial activities at the Portsmouth facility that were completed to address TCE contamination associated with the X-701B groundwater plume and to make recommendations for future efforts. The Independent Technical Review team was provided with a detailed and specific charter. The charter requested that the technical team first review the past and current activities completed for the X-701B groundwater remedy for trichloroethene (TCE) in accordance with a Decision Document that was issued by Ohio EPA on December 8, 2003 and a Work Plan that was approved by Ohio EPA on September 22, 2006. The remedy for X-701B divides the activities into four phases: Phase I - Initial Source Area Treatment, Phase II - Expanded Source Area Treatment, Phase III - Evaluation and Reporting, and Phase IV - Downgradient Remediation and Confirmation of Source Area Treatment. Phase I of the remedy was completed during FY2006, and DOE has now completed six oxidant injection events within Phase II. The Independent Technical Review team was asked to evaluate Phase II activities, including soil and groundwater results, and to determine whether or not the criteria that were defined in the Work Plan for the Phase II end point had been met. The following criteria are defined in the Work Plan as an acceptable Phase II end point: (1) Groundwater samples from the identified source area monitoring wells have concentrations below the Preliminary Remediation Goal (PRG) for TCE in groundwater, or (2) The remedy is no longer effective in removing TCE mass from the source area. In addition, the charter specifies that if the Review Team determines that the Phase II endpoint has not been reached, then the team should address the following issues: (1) If additional injection events are recommended, the team should identify the type of injection and target soil horizon for these injections; (2) Consider the feasibility of declaring Technical Impracticability and proceeding with the RCRA Cap for the X-701B; and (3) Provide a summary of other cost-effective technologies that could be implemented (especially for the lower Gallia). The Independent Technical Review team focused its evaluation solely on the X-701B source zone and contaminant plume. It did not review current or planned remedial activities at other plumes, waste areas, or landfills at the Portsmouth site, nor did it attempt to integrate such activities into its recommendations for X-701B. However, the ultimate selection of a remedy for X-701B by site personnel and regulators should take into account potentially synergistic efforts at other waste areas. Assessment of remedial alternatives in the context of site-wide management practices may reveal opportunities for leveraging and savings that would not otherwise be identified. For example, the cost of source-zone excavation or construction of a permeable reactive barrier at X-701B might be substantially reduced if contaminated soil could be buried on site at an existing or planned landfill. This allowance would improve the feasibility and competitiveness of both remedies. A comprehensive examination of ongoing and future environmental activities across the Portsmouth Gaseous Diffusion Plant is necessary to optimize the selection and timing of X-701B remediation with respect to cleanup efficiency, safety, and economics. A selected group of technical experts attended the technical workshop at the Portsmouth Gaseous Diffusion Plant from November 18 through 21, 2008. During the first day of the workshop, both contractor and DOE site personnel briefed the workshop participants and took them on a tour of the X-701B site. The initial briefing was attended by representatives of Ohio EPA who participated in the discussions. On subsequent days, the team reviewed baseline data and reports, were provided additional technical information from site personnel, evaluated work plans, determined critical issues and uncertainties, and recommended alternatives. This report documents the findings and recommendations of the independent technical review team

Determining Contaminant Distribution and Migration by Integrating Data from Multiple Cone Penetrometer-Based Tools

The cone penetrometer has been used for geologic characterization at the U.S. Department of Energy-owned Savannah River Site for the past seven years

Scientific Opportunities for Monitoring of Environmental Remediation Sites (SOMERS) - 12224

ABSTRACT The US Department of Energy (DOE) is responsible for risk reduction and cleanup of its nuclear weapons complex. DOE maintains the largest cleanup program in the world, currently spanning over a million acres in 13 states. The inventory of contaminated materials includes 90 million gallons of radioactive waste, 6.4 trillion liters of groundwater, and 40 million cubic meters of soil and debris. It is not feasible to completely restore many sites to predisposal conditions. Any contamination left in place will require monitoring, engineering controls and/or land use restrictions to protect human health and environment. Research and development efforts to date have focused on improving characterization and remediation. Yet, monitoring will result in the largest life-cycle costs and will be critical to improving performance and protection. Through an inter-disciplinary effort, DOE is addressing a need to advance monitoring approaches from sole reliance on cost-and labor-intensive point-source monitoring to integrated systems-based approaches such as flux-based approaches and the use of early indicator parameters. Key objectives include identifying current scientific, technical and implementation opportunities and challenges, prioritizing science and technology strategies to meet current needs within the DOE complex for the most challenging environments, and developing an integrated and risk-informed monitoring framework

Scientific Opportunities for Monitoring at Environmental Remediation Sites (SOMERS): Integrated Systems-Based Approaches to Monitoring

Through an inter-disciplinary effort, DOE is addressing a need to advance monitoring approaches from sole reliance on cost- and labor-intensive point-source monitoring to integrated systems-based approaches such as flux-based approaches and the use of early indicator parameters. Key objectives include identifying current scientific, technical and implementation opportunities and challenges, prioritizing science and technology strategies to meet current needs within the DOE complex for the most challenging environments, and developing an integrated and risk-informed monitoring framework

A Pre-Landing Assessment of Regolith Properties at the InSight Landing Site

This article discusses relevant physical properties of the regolith at the Mars InSight landing site as understood prior to landing of the spacecraft. InSight will land in the northern lowland plains of Mars, close to the equator, where the regolith is estimated to be ≥3--5 m thick. These investigations of physical properties have relied on data collected from Mars orbital measurements, previously collected lander and rover data, results of studies of data and samples from Apollo lunar missions, laboratory measurements on regolith simulants, and theoretical studies. The investigations include changes in properties with depth and temperature. Mechanical properties investigated include density, grain-size distribution, cohesion, and angle of internal friction. Thermophysical properties include thermal inertia, surface emissivity and albedo, thermal conductivity and diffusivity, and specific heat. Regolith elastic properties not only include parameters that control seismic wave velocities in the immediate vicinity of the Insight lander but also coupling of the lander and other potential noise sources to the InSight broadband seismometer. The related properties include Poisson’s ratio, P- and S-wave velocities, Young’s modulus, and seismic attenuation. Finally, mass diffusivity was investigated to estimate gas movements in the regolith driven by atmospheric pressure changes. Physical properties presented here are all to some degree speculative. However, they form a basis for interpretation of the early data to be returned from the InSight mission.Additional co-authors: Nick Teanby and Sharon Keda