Archived
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Location
Lexington, KY
Start Date
7-5-2026 11:00 AM
End Date
7-5-2026 11:30 AM
Description
Monitored Natural Attenuation (MNA) refers to the reliance on natural attenuation processes (within the context of a carefully controlled and monitored site cleanup approach) to meet groundwater protection standards (GPS) for a CCR unit within a reasonable time frame (USEPA, 1999). MNA is being evaluated as an adaptive management strategy for a CCR unit groundwater plume with statistically significant lithium concentrations above GPS, though with little risk of offsite migration. A previous MNA evaluation was performed for the lithium plume following the United States Environmental Protection Agency (USEPA) “tiered lines of evidence approach” (USEPA, 2015), which determined that there were insufficient groundwater data from within the core of the plume to complete the first tier of the evaluation. Five new monitoring wells were installed within the core of the lithium plume to support additional evaluation of the spatial distribution and temporal variability of lithium concentrations. Groundwater monitoring results from the new wells, and results from soils collected during the well installation process, indicate that natural attenuation may be occurring for lithium within the plume. Data from the new wells are also being used to refine the lithium plume shape and extent and improve understanding of groundwater flow directions across the site. Additional work is being conducted to evaluate the feasibility of MNA as a remedial alternative; however, preliminary data support its continued evaluation. This evaluation demonstrates that MNA, if deemed a viable remedy through the tiered evaluation process, may be useful at CCR sites where existing infrastructure and/or site operations prevent the installation of active remediation systems. It also helps demonstrate the importance of having sufficient monitoring infrastructure to determine the nature and extent of a contaminant plume, which is a key step when selecting and implementing a remedy at a CCR site.
Document Type
Presentation
Archival?
Archival
Included in
Energy Policy Commons, Environmental Indicators and Impact Assessment Commons, Environmental Monitoring Commons, Mining Engineering Commons, Oil, Gas, and Energy Commons, Structural Materials Commons, Sustainability Commons
Monitored Natural Attenuation Evaluation and Additional Characterization of a CCR Unit Lithium Groundwater Plume
Lexington, KY
Monitored Natural Attenuation (MNA) refers to the reliance on natural attenuation processes (within the context of a carefully controlled and monitored site cleanup approach) to meet groundwater protection standards (GPS) for a CCR unit within a reasonable time frame (USEPA, 1999). MNA is being evaluated as an adaptive management strategy for a CCR unit groundwater plume with statistically significant lithium concentrations above GPS, though with little risk of offsite migration. A previous MNA evaluation was performed for the lithium plume following the United States Environmental Protection Agency (USEPA) “tiered lines of evidence approach” (USEPA, 2015), which determined that there were insufficient groundwater data from within the core of the plume to complete the first tier of the evaluation. Five new monitoring wells were installed within the core of the lithium plume to support additional evaluation of the spatial distribution and temporal variability of lithium concentrations. Groundwater monitoring results from the new wells, and results from soils collected during the well installation process, indicate that natural attenuation may be occurring for lithium within the plume. Data from the new wells are also being used to refine the lithium plume shape and extent and improve understanding of groundwater flow directions across the site. Additional work is being conducted to evaluate the feasibility of MNA as a remedial alternative; however, preliminary data support its continued evaluation. This evaluation demonstrates that MNA, if deemed a viable remedy through the tiered evaluation process, may be useful at CCR sites where existing infrastructure and/or site operations prevent the installation of active remediation systems. It also helps demonstrate the importance of having sufficient monitoring infrastructure to determine the nature and extent of a contaminant plume, which is a key step when selecting and implementing a remedy at a CCR site.
