Archived
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Location
Lexington, Kentucky
Start Date
5-5-2026 2:00 PM
End Date
5-5-2026 2:30 PM
Description
In 2017, many power utilities adopted statistical methods to comply with the EPA’s Coal Combustion Residuals (CCR) Rule under the Hazardous and Solid Waste Management System. By 2017–2018, most owners completed initial statistical evaluations for detection and assessment monitoring to meet CCR deadlines. Groundwater sampling and analysis requirements in Parts 257.95, 257.98, and 257.102 are critical for compliance, yet implementation is complex. Subsections 257.93(f) and (g) lack clarity on which statistical tests to apply or how to address distributions and outliers. Additionally, the Rule does not specify when or how to update background threshold values (BTVs), though EPA’s Unified Guidance recommends revising BTVs every 1–2 years for sites with quarterly sampling. Regular updates improve confidence in decisions regarding assessment monitoring, corrective measures, and remedy completion. Adding new background samples years later can alter BTVs and groundwater protection standards, affecting statistically significant level (SSL) occurrences, corrective action status, constituent lists for remediation, geochemical interpretations, and even post-public meeting evaluations. Further changes may arise from EPA reviews, which often involve re-running statistical tests and commenting on distributions, elevated concentrations, turbidity, or dilution factors. This presentation examines the cost and public perception impacts of changing BTVs and groundwater standards, shares lessons learned from EPA reviews and outlines how our decision-making process for BTV determination has evolved to address regulatory feedback. Key topics: • Guidance and best practices for updating groundwater background values under the CCR Rule. • Owner cost and public perception implications of BTV changes. • Lessons from EPA reviews of statistical background reports.
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
IMPACTS OF UPDATING BACKGROUND GROUNDWATER STATISTICS FOR CCR COMPLIANCE
Lexington, Kentucky
In 2017, many power utilities adopted statistical methods to comply with the EPA’s Coal Combustion Residuals (CCR) Rule under the Hazardous and Solid Waste Management System. By 2017–2018, most owners completed initial statistical evaluations for detection and assessment monitoring to meet CCR deadlines. Groundwater sampling and analysis requirements in Parts 257.95, 257.98, and 257.102 are critical for compliance, yet implementation is complex. Subsections 257.93(f) and (g) lack clarity on which statistical tests to apply or how to address distributions and outliers. Additionally, the Rule does not specify when or how to update background threshold values (BTVs), though EPA’s Unified Guidance recommends revising BTVs every 1–2 years for sites with quarterly sampling. Regular updates improve confidence in decisions regarding assessment monitoring, corrective measures, and remedy completion. Adding new background samples years later can alter BTVs and groundwater protection standards, affecting statistically significant level (SSL) occurrences, corrective action status, constituent lists for remediation, geochemical interpretations, and even post-public meeting evaluations. Further changes may arise from EPA reviews, which often involve re-running statistical tests and commenting on distributions, elevated concentrations, turbidity, or dilution factors. This presentation examines the cost and public perception impacts of changing BTVs and groundwater standards, shares lessons learned from EPA reviews and outlines how our decision-making process for BTV determination has evolved to address regulatory feedback. Key topics: • Guidance and best practices for updating groundwater background values under the CCR Rule. • Owner cost and public perception implications of BTV changes. • Lessons from EPA reviews of statistical background reports.
