BY MAIRE O’NEILL
[email protected]
Chris Krambis, New Mexico Environment Department Hydrogeologist, stated Wednesday evening to Los Alamos County Board of Utilities that the Department of Energy Environmental Management should focus on extracting chromium from the plume at Los Alamos National Laboratory.
Krambis stated that extraction is the most effective method to control plume migration and remove bulk.
He also noted that the current Interim Measure implemented by EMLA and legacy contractor N3B focuses on the top 50-60ft and that the plume’s depth, which was discovered in 2005 has not been determined.
Krambis informed the Board that there have been three DOE/EM Workplans under the two Consent Orders which govern the Interim Measures. NMED required that the Lab examine the feasibility to pump contaminated groundwater out the regional well to recover the contaminant. This was the first workplan submitted in 2013. He stated that it was possible and created CrEx-1, an interim measure infrastructure well. This well was located along the Pueblo of San Ildefonso’s boundary in 2014.
The NMED Hazardous Waste Bureau expressed concern about the possibility that this plume could migrate off Labs property. Krambis stated that they had noted in their annual report that groundwater could flow anywhere from 40 to 50 metres per year, which is a significant rate for flat hydraulic gradient.
He stated that a second plan was issued in 2015 that focused on the control of this migration. The Consent Order was modified sometime around 2016. The Lab installed and tested more extraction wells, injection wells for the Interim measure in 2017.
The DOE then submitted a 3rd workplan, which really serves to provide methods to gauge performance through reporting metrics over a three year period. This was received in 2018. We have received six reports covering 3 years of performance for the Interim Measures to date. The whole strategy for evaluating performance was based on the assumption that the majority of the chromium contamination in regional aquifers is within the top 50-60 feet of regional aquifer. Krambis stated that none of the wells reached much deeper than this.
Krambis stated that the Hazardous Waste Bureau noticed that the assumption wasn’t true because all the wells drilled since the workplan was submitted have shown that contamination is quite deep in certain areas. He stated that the plume’s vertical extent is still unknown.
One of the key metrics to evaluate the performance of the Interim Measures is mapping the water table because it provides insight into what the Interim Measure system – extraction and injection – is actually doing and how the system operation may impact the water table and the migration of the plume and the recovery of the plume. The Lab’s mapping process is not perfect. We don’t believe there is any hydraulic control along the eastern border of that plume. Its mostly used as an injection operation, not extraction. We have observed what we call unfavorable reactions in the workplan. This appears to be due to the injection phase. The Lab also needs to address other technical concerns.
Krambis then reviewed the Interim Measure objectives of DOE. He highlighted the fact that the strategy for the Interim Measure is centered on the top 50-60 feet region’s aquifer.
The main objective is to reduce the concentration of monitoring well R-50 over three years to levels below 50 parts per million (ppb) as established by the state. That has been achieved largely within the three year timeline, he stated. They managed to reduce it from 150 ppb to barely detectable levels. Where did that mass end? The secondary objective is control of migration in the eastern edges of the plume. This remains to be confirmed.
Krambis presented the DOE metrics to evaluate performance over the three-year period. These metrics include concentration plots over the time for various contaminants, tracer analyses to show where water is entering the aquifer through injection wells, water table mapping which is a key metric to assess changes in gradient that would prevent migration from LANL property.
Krambis stated that mass removal estimates are also a key element and should be more stressed.
He showed maps showing all the wells in the chromium plume region and pointed out the Los Alamos County production Well PM-3, which is located to northeast of the plume. One map had Interim Measures superimposed.
Krambis talked about an in-situ pilot study from 2017 that involved the injections of molasses into monitoring Well R-28 and sodium thionite into Monitoring Well R-42 to determine if they could alter the chemistry to reduce and precipitate the Chromium. He stated that R-28, R-42 and possibly R-42 have not been used for monitoring in the past. However, it was agreed to replace them both.
He stated that the injection wells in this area should be doing something to stop the migration. However, we don’t see any evidence of that.
Krambis explained that what is being observed in the performance monitoring wells R-601 and R-45 is what Krambis calls unfavorable response.
It appears that the injection operation has not been as successful as it was expected. The shining star is however the extraction at Extraction Wells 2, and 4, which is doing extremely well. He said that it is drawing down the water table and providing for the removal of the chromium masses quite effectively.
Krambis stated that almost 100 pounds per year of chromium is extracted by the extraction wells in the central part of the plume.
It would be a good idea to pay more attention to this. It will also stop migration as all the water from the water table will flow to this circle. He said that this is a positive thing that should be emphasized in the future.
Krambis pointed out on the maps that the circle in which effective capture was possible by pumping water from is being seen.
We don’t believe that the injection is doing what was expected. This was creating a barrier to further treatment. [continued] migration. This is just below the water table. He said that many of these wells have larger screens. As a result, when you map the deeper levels of water, or heads as we call it, we don’t see any effects from pumping. The assumption was earlier that a lot of this mass – they only focused on the top 50 or 60 feet – isnt being sufficiently addressed by the interim measures for this center area all the way out to R-70 where we know contamination is deeper. These water levels reflect the depths of 70 to 100 feet below the watertable. Therefore, the Interim Measure, as it was designed and implemented now would not prevent the migration at depth.
Krambis stated that NMED feels it needs to reevaluate the strategy after a three-year evaluation period. A new workplan will be developed to refocus the Interim Measure and achieve its goal in accordance to the consent order.
This is Milestone 2 of this year’s workplan. It will be received at end September. We anticipate that the Interim Measure will allow for flexibility for adjustments to our system as needed. Our focus is on the extraction. Data so far has shown that it is the best method to both control migration and to remove excess mass.
Krambis stated that injection problems will need to addressed and some modeling input would also be required. It would be necessary to consider the entire thickness of plume and not just the top 50-60 feet.
We don’t know how deep. It is at least 100 feet below the surface. We need better metrics to evaluate performance. R-50 has been met, but we don’t know what it means. Is it possible that the injected water pushed that material towards R61 Is it still there? He stated that we need better metrics, and that we must start moving forward towards corrective actions.
Krambis stated that the total amount believed to have been released from the one cooling tower was 160,000 lbs.
Most of this mass is in the wetlands. Some of that mass is still in perched aquifer, which is a very discontinuous system. The rest is in regional aquifer. I don’t believe they ever estimated its actual mass in regional aquifer. Krambis stated that they should.
Krambis replied that the water used for the injection process is derived from the extraction wells.
He said that they first take the water from the extraction wells and treat it with an Ion Exchange before injecting it into the five injection holes.
One board member stated that it worries him and has always concerned him that the contamination issue has existed since 2005. It has taken more than a decade for the authorities to get serious about extracting the plume.
White Rock is being contaminated by PM-3 water. This has always concerned me. I’m disappointed that the Lab hasn’t been more open with the public about this.
Were at the end of the evaluation for the Interim measure and I don’t think were too happy about it. However, we are working with Lab within the limits of the Consent Order. Krambis replied that we must work in this manner, at the very least, the Hazardous Waste Bureau. We are trying get things to a more logical place. We are moving in the right direction, I believe. We are asking DOE for more plans to drill monitoring wells to evaluate the plume and its depth. With the new Interim measure workplan, we can hopefully get it in a better condition and will be able to move on to the Corrective measures in the near future.
Krambis was also questioned if NMED is restricted in what they can ask the Lab to do regarding cleanups as part of the regulatory process.
It is clear that there is consensus that it needs to be addressed. It doesn’t matter if it is offsite, it must be addressed in a proactive way. They tried two different approaches, the geochemical one didn’t work and then this Interim Measure which is a pump and treat approach. There wasn’t consensus on which approach was best. The Interim Measure emphasizes pump and treat extract specifically. It doesn’t matter regulatorily whether it goes off the LANL Property or not, he said.
Krambis answered, “We don’t have enough information to know when the plume would reach PM-3.” That’s what we were trying get them to assess.
Asked if he has an idea of what a better Interim Measure would be, Krambis said, Absolutely – turn all the injection wells into extraction wells and well have to figure out what to do with the treated water but I think extraction and treatment at the surface and treated to a way that maybe the Lab can use that water instead of injecting it. I believe injecting the water is causing undesirable effects. I hoped they would only concentrate on extraction.
Los Alamos County’s Public Utilities Manager Philo Shelton said Thursday that he looks forward to having a new well drilled to give us “new data that will help determine the nature, extent, and depth of the chromium plume”
DOE/EM-LA Manager Michael Mikolanis said Friday morning that EM-LA is aware of NMED’s technical perspectives on the chromium Interim Measure perfomance.
“While we have differing professional opinions on a relatively small number of conclusions that have been drawn, we continue to work collaboratively with the state of New Mexico to evaluate and model the dataset already collected,” he said. “We will consider if adjustments to Chromium Interim operations are warranted and whether additional wells should be installed. This evaluation will enable us to progress to a final remedy.”
Mikolanis added that nearby water-supply wellswhich are regularly monitoredremain unaffected by the plume”.
The Board of Public Utilities is scheduled to hear a presentation regarding the chromium-plumme during their Mar. 2 meeting from Danny Katzman, groundwater remediation program manager for Tech2 Solutions, a subcontractor to N2B’s Water Program. N3B is the legacy contractor for EM/LA’s waste cleanup.
For more information on the chromium plume, see the Reporter’s 2019 article here: https://losalamosreporter.com/2019/05/30/chromium-interim-measure-in-full-swing-in-mortendad-canyon/
