Archived
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Location
Lexington, Kentucky
Start Date
5-5-2026 1:00 PM
End Date
5-5-2026 1:30 PM
Description
US EPA expanded the scope of CCR regulations in 2024 to areas of historical CCR placement not regulated under the 2015 CCR rule, including CCR used as fill. US EPA presented new risk analyses specific to CCRMU fills and defined different regulations for CCRMU fills from 1 to 1,000 tons, noting uncertainty as to whether there was a size of CCRMU fill below which acceptable risks could be expected. This research fills US EPA's stated data gap by modeling and analyzing impacts from small CCRMU fills. Modeling was conducted using the same methods, models, and most of the same inputs used by US EPA. The modeling results demonstrate that smaller CCRMU fills result in lower groundwater concentrations, and thus lower risk, than determined by US EPA for larger CCRMU fills. Specifically, 90th percentile arsenic (III) concentrations fell below the Groundwater Protection Standard (GWPS) for all modeled tonnages at variable distances from 3-1,000 ft downgradient of small CCRMU fills. Results for fixed downgradient distances were also evaluated. Additionally, allowing well locations to vary off the plume centerline reduced median concentrations by 86% and 90th percentile concentrations by 80% at 1,000 ft. downgradient. These results provide utilities, regulators, and permitting authorities technical support to assess whether small CCRMU fill placements have a reasonable probability of adverse impacts on human health or the environment.
Document Type
Presentation
Archival?
Archival
Included in
Energy Systems Commons, Environmental Indicators and Impact Assessment Commons, Environmental Monitoring Commons, Mining Engineering Commons, Oil, Gas, and Energy Commons, Structural Materials Commons, Sustainability Commons
Risk Evaluation of Small Coal Combustion Residual Management Unit (CCRMU) Fills
Lexington, Kentucky
US EPA expanded the scope of CCR regulations in 2024 to areas of historical CCR placement not regulated under the 2015 CCR rule, including CCR used as fill. US EPA presented new risk analyses specific to CCRMU fills and defined different regulations for CCRMU fills from 1 to 1,000 tons, noting uncertainty as to whether there was a size of CCRMU fill below which acceptable risks could be expected. This research fills US EPA's stated data gap by modeling and analyzing impacts from small CCRMU fills. Modeling was conducted using the same methods, models, and most of the same inputs used by US EPA. The modeling results demonstrate that smaller CCRMU fills result in lower groundwater concentrations, and thus lower risk, than determined by US EPA for larger CCRMU fills. Specifically, 90th percentile arsenic (III) concentrations fell below the Groundwater Protection Standard (GWPS) for all modeled tonnages at variable distances from 3-1,000 ft downgradient of small CCRMU fills. Results for fixed downgradient distances were also evaluated. Additionally, allowing well locations to vary off the plume centerline reduced median concentrations by 86% and 90th percentile concentrations by 80% at 1,000 ft. downgradient. These results provide utilities, regulators, and permitting authorities technical support to assess whether small CCRMU fill placements have a reasonable probability of adverse impacts on human health or the environment.
