Contaminant Flux and Fate in Fractured Bedrock

Dr. Charles Schaefer | CDM Smith

ER-201570-T2

Objectives of the Demonstration

The overall goal of this project was to develop and implement a short (i.e., half day) seminar that highlights recent advances in the fate and transport of chlorinated solvents in fractured bedrock, and how these advances can be used for improved management of the DoD’s fractured rock sites. DoD Remedial Project Managers (RPMs) overseeing fractured bedrock sites impacted with chlorinated ethenes were specifically targeted, along with the regulators and contractors involved with these sites. 

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Technology Description

This project used an innovative approach to technology transfer. Key innovative aspects to this approach included the following:

  • Surgical targeting of key DoD fractured bedrock sites. By focusing on RPMs (and regulators) at key DoD sites where chlorinated solvents in fractured bedrock remain a large liability, the beneficial impacts of technology transfer were maximized.
  • Incorporation of site-specific data into the seminars. Discussing the RPM’s site during the seminar provided the RPM and regulators with added incentive to participate. More importantly, incorporating site-specific details and high priority needs helps to “bridge the gap” between the research and application to facilitate technology transfer.
  • Seminar presented by those who were involved with the fundamental science and field application (remediation and site assessment). Thus, the presentation focused on transitioning fundamental science to practical application that can be readily utilized for improved site management by DoD RPMs.

The technologies presented in the seminars were all mature, having been successfully demonstrated through SERDP and ESTCP, and/or published in the peer reviewed literature. The half-day seminar covered a range of topics related to contaminant flux in fractured bedrock, and addressed areas of concern including site assessment, down-gradient contaminant migration, rock matrix processes (e.g., diffusion, sorption, reaction), and the practical limits of remedial effectiveness. Topics included the following:

  • Identification of contaminant flux zones in fractures
  • DNAPL in fractured rock (architecture and impacts on groundwater)
  • Diffusion in rock matrices
  • Sorption and abiotic reaction in rock matrices
  • Estimating plume longevity and practical limits of remedial effectiveness (via models and field testing techniques)
  • Discussion of remedial approaches

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Demonstration Results

Seminars were conducted at the following key DoD sites:

  • Air Force Civil Engineering Center (San Antonio, TX)
  • Loring Air Force Base (Portland, ME)
  • Calf Pasture Point - U.S. Navy (Davisville, RI)
  • Pease Air Force Base (Portsmouth, NH)
  • Moses Lake - U.S. Army Corps of Engineers (WA)
  • Edwards Air Force Base (CA)

In addition, a seminar was given to the fractured rock working group at the Interstate Technology & Regulatory Council (ITRC) in Denver, CO. The  presentation slides for these seminars is available on this web page.

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Implementation Issues

The DoD has dozens of fractured bedrock sites impacted by chlorinated solvents. Cost effective long-term solutions are lacking at most of these sites. The technologies and technical approaches presented as part of these seminars can provide a plausible path forward at many of these sites. It is expected that implementation of these technologies and tools will follow at other DoD sites as new industry standards are set.

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Points of Contact

Principal Investigator

Dr. Charles Schaefer

CDM Smith

Phone: 732-590-4633

Program Manager

Environmental Restoration

SERDP and ESTCP

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