239-12 A Long Way to Go: Portfolio-Scale Modeling Highlights the Case for Efficient Containment at Federal PFAS Groundwater Sites

Session: Federal PFAS Remediation: Successes and Challenges

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Per- and polyfluoroalkyl substances (PFAS) pose a uniquely persistent challenge to the Department of Defense and other federal remediation programs. We synthesized chemical property constraints, cost curves, and simplified remediation modeling tools to compare two contrasting groundwater management paradigms across more than 10,000 hypothetical PFAS-contaminated sites: an Intensive strategy centered on mass removal, and an Efficient strategy that deploys more containment-focused interim remedies. Portfolio modeling suggests the Efficient strategy could bring every site under control within approximately 15 years while consuming only 30% of a hypothetical nationwide PFAS groundwater remediation budget—achieving higher cumulative risk reduction than the Intensive option, even if future budgets were to double.

Field performance data and life-cycle cost analyses generally indicate that permeable sorptive barriers (PSBs) are less costly than pump-and-treat (P&T) systems at low- to moderate-mass-flux sites. While PSBs provide immediate flux reduction, long-term stewardship obligations may remain. Coupling near-term containment with longer-term mass removal offers a phased pathway that better aligns limited funds with current remediation technology capabilities and evolving regulatory expectations.

These findings challenge the prevailing notion that aggressive mass removal at a subset of “priority” plumes represents best practice. Instead, a risk-based, portfolio-wide allocation framework maximizes exposure reduction across sites. Key recommendations include: (i) initially regulating based on mass discharge reduction rather than low ng/L concentration targets; (ii) deploying the few available PFAS groundwater technologies in their optimal “sweet spots”; and (iii) avoiding large-scale deployment of costly, intensive mass removal technologies that could divert resources from other sites in need of remediation.

Although “A Long Way to Go” aptly describes the PFAS remediation challenge, adopting an Efficient, containment-first paradigm may offer the fastest route to meaningful risk reduction, particularly under the financial and technological constraints currently facing federal cleanup programs.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6876

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