BY MAIRE O’NEILL
maire@losalamosreporter.com
A nearly 1000-page report has been released by an independent review team (IRT) of 15 experts convened in March 2024 by the Department of Energy Environmental Management Los Alamos Field Office (DOE-EMLA) and the New Mexico Environment Department to assess issues in dispute between the two ages on the Chromium Interim Measures Remediation System in Mortendad Canyon.
The assembly and management of the IRT were directed by Dr. Ines Triay, the Interim Dean of
the College of Engineering of Computing and the Executive Director for the Applied Research
Center (ARC) at Florida International University (FIU). The report notes that Dr. Triay is recognized as a foremost expert on environmental management and has worked in this area as a researcher, a visionary leader, and a manager at LANL, DOE, and FIU.
“At DOE, she managed the largest,most complex nuclear environmental cleanup program in the world as Assistant Secretary for Environmental Management, a Presidential appointment, confirmed by the U.S. Senate, with a budget of $6 billion per annum, and a workforce of 34,000 at 114 sites across the U.S. Dr. Triay has been widely recognized for her many accomplishments in science and engineering including the Los Alamos Distinguished Performance Award, Presidential Rank Award, the DOE Secretary Exceptional Service Award, the National Award for Nuclear Science, and the Dixie Lee Ray Award from the American Society of Mechanical Engineers,” the report says.
A consensus finding of the IRT is that the Interim Measures (IM) at a limited and/or altered capacity, should be restarted as soon as possible. It should be noted that prior to finalization of the report, EM-LA worked together with NMED to resume partial operation of the Chromium IM on September 30. The IM is running 24/7 as expected with two extraction wells and three injection wells.
“There is clear benefit to the near- and long-term cleanup objectives of containing and recovering chromium located upgradient of the extraction wells rather than allowing it to continue migrating without intercession. The IRT recognizes that aspects of the historical configuration and operation of the IM extraction and injection wells likely resulted in incomplete hydraulic containment of the chromium plume. Consequently, to continue contaminant mass recovery and maintain some degree of hydraulic containment of at least the (apparent) core of the plume, the IM needs to be operated in a revised configuration while further analyses improve the remedy,” the report states.
The IRT believes that a collaborative effort between DOE-EM-LA, NMED, and other parties, could result in a suitable near-term operating configuration determined through data-driven analyses supported by groundwater modeling of the chromium plume and capture zone analysis.
The IRT report also presents the results of empirical data analyses and model-based calculations that the IRT completed to demonstrate that the IM can be confidently restarted in one of several alternative configurations to achieve these limited options.
“However, because the identification, evaluation, and implementation of any alternatives would be time-consuming, seeking such alternatives at this time should not further delay a limited restart of the IM in the near-term,” the report says.
The current IM, which began partial operations in 2017 and became fully operational in 2018, consists of a groundwater pump-and-treat (P&T) hydraulic control system along with five extraction wells on the south and east margins of the plume that extract chromium-contaminated water that is treated before it is reinjected in an attempt to create a hydraulic barrier to prevent the plume from crossing the boundary of the Pueblo de San Ildefonso.
In March 2023, increases in chromium concentration in two monitoring wells as well as the discovery during IM operations of contamination at deeper levels than expected became cause for concern. NMED ordered EM-LA to cease order the injection of the treated water to make sure chromium was not migrating beyond hydraulic control at concentrations above the 50 ppb state standard.
From September 2023 to March 2024, the report notes that “an exchange of correspondence took place between NMED and EM-LA to discuss restarting the IM, without resolution. Both agencies publicly discussed their concerns and in March they agreed to convene the IRT for the purpose of “assessing the issues in dispute and recommending possible solutions.
See link below for background:
https://losalamosreporter.com/2023/08/30/doe-to-pay-for-independent-advisor-to-help-move-lanl-chromium-cleanup-through-impasse-with-nm-environment-department/
Specific questions grouped into five topics were developed by the parties for the IRT to address. They are:
- the performance of the IM in achieving hydraulic control of the chromium plume,
- the modeling of the chromium plume,
- the corrective actions proposed by NMED,
- regulatory matters, and
- well design issues.
In their finding that the IM should be restarted in some capaity as soon as possible, the IRT noted that there is “clear benefit to the near- and long-term cleanup objectives of containing and recovering chromium located upgradient of the extraction wells rather than allowing it to continue migrating without intercession”.
The IRT also recommends transition to a groundwater flow and transport simulator (e.g., MODFLOW-6) “that has a wider user community with well-established application areas, similar to this site and its remedy design/implementation needs” as well as the establishment of a small collaborative modeling working group that would include members from EM-LA, NMED, and other stakeholders and technical experts. (EM-LA has used the FEHM model – Finite Element Heat and Mass – developed by LANL over the past 30 years.)
The IRT determined that chromium investigation and remediation efforts would benefit from “more rapid and cost effective drilling and well installation procedures to maximize the data that can be obtained with available time and funding.
In addition to Prof. Triay, other members of the IRT are:
Vedat Batu, PhD, P.E.
Fred Day-Lewis, PhD
Inci Demirkanli, PhD
J.F. Devlin, PhD
Scott Ellinger, M.S. P.G.
J. Alexandra Hakala, PhD
Brian B. Looney, PhD
Charles J. Newell, PhD, P.E., BCEE
Sorab Panday, PhD
Mark J. Rigali, PhD
Daniel B. Stephens, PhD
Matthew Tonkin, PhD
Haruko Wainwright, PhD
David Wilson, MS, P.E.
The full report may be viewed at https://ext.em-la.doe.gov/GovFTPFiles/api/GetFiles/GetFile?fileName=EMID-703545_Final_IRT_Report_123024.pdf
EM-LA and NMED are expected to hold public meetings in late January to present the findings of the IRT.