N3B Technical Manager Danny Katzman addresses a large crowd at the Jan. 28 Voices of Los Alamos meeting. Photo by Maire O’Neill/losalamosreporter.com
BY MAIRE O’NEILL
Danny Katzman, Technical Manager for N3B, the legacy waste cleanup contractor at Los Alamos National Laboratory was the guest speaker at the Jan. 28 Voices of Los Alamos meeting where he addressed the RDX and chromium projects at LANL.
Katzman showed depictions of what he called the very complicated geological area that sits below ground on the Pajarito Plateau adding that there are a number of different places that water occurs and that it varies on different parts of the Plateau. He showed where sand and gravel gathers in the bottoms of the canyons and said sometimes natural water comes off the mountains and sometimes it comes from springs that sit along the canyon edge where rock layers emit water that comes across in rock partings. He said there can be a body of water called alluvial groundwater in the bottom of the canyons that sometimes might be from sources at the Laboratory that discharge a permitted effluent or water from a facility out into the canyon.
“Those waters tend to percolate downward where they form what we call perched intermediate groundwater, where a rock layer might have a little different porosity in it allowing water to make its way down there. It can occur anywhere from generally 200 feet at its shallowest to as much as 900 or 1,000 feet,” Katzman said. “Below that is probably the most important of the zones which is called the regional aquifer (which is the groundwater body that sits everywhere beneath the Pajarito Plateau) and it is the water that the County accesses for its supply. So we all drink groundwater from the regional aquifer.”
Katzman explained that many of the water supply wells owned by Los Alamos County are actually on the Laboratory property.
“The Laboratory and the Department of Energy gives the County access to those wells and those are the wells that provide water to all of us for any domestic purpose. It’s also the source for the Laboratory itself. Those wells have very long penetrations down into the regional groundwater so they may start at 100 or 200 feet below the water table and extend for maybe another 1,000 feet into the sand and gravels where all that water is provided for the water supply system,” he said.
Katzman said TA-16, where the RDX Project work is located, is part of an area that has always been known as the high explosives corridor where a lot of high explosives technical work was done. He said back in the day high explosives for use in nuclear weapons tests were machined at Building 220. One of those explosives was Royal Demolition Explosive.
“They needed to cool this material down. You can imagine – they are machining on big lathes. They had to keep that material washed out and make sure it didn’t go explosive on them. So the water that was used to cool all the machining down was actually back in the day released directly out of the building through an outfall and millions of gallons of water went out of this building. It had high explosive residues in it and as it flowed out across the ground surface, it contaminated the soils,” he said, adding that wherever water percolated down through the groundwater zones the RDX went down with it as well.
Katzman said the RDX soil contamination was first discovered in investigations that were done back in the 1990s.
“We’ve been studying this problem for a very long time. We’ve even done some remediation. I think there’s kind of this new emergence and I think it’s appropriate that we have this new awareness of the RDX contamination because we’re really starting to focus on it in the regional groundwater. But I think it has led some people to believe, at least in part of the community that I interact with, that somehow the RDX has just shown up and that we just discovered it. One thing I want to leave you with is that we’ve studying the RDX Project now for 15 or 20 years. So we’re at a relatively mature level of the project and really starting to focus in on the groundwater portion of it. It’s been a high priority project for the environmental program for quite some time,” he said.
Katzman explained that water flowing across the surface from Building 220 actually created a pretty severe contamination area where plants could not grow. He said there were two different major cleanups done out there, one back in 2000-2001 and another around 2010 where well over 1500 cubic yards of contaminated material were essentially moved out of the area and that the area is essentially now a “clean site”.
Katzman said some of the rock layers in the area are very porous which allows water to move very quickly though them. He said the Laboratory wanted to keep water from those layers from intercepting with springs elsewhere downgrade so grout was injected into the high-porosity layers to try to block them
“Don’t know how well it worked because it’s all subsurface but we thought it was a good thing to do,” he said.
“We finished the soil cleaning, the grouting and a handful of other actions in the near-surface environment, and issued what regulatorily the New Mexico Environment Department calls a ‘Remedy Completion Report’ in 2017 and that kind of put a bow around the surface portion of the work we needed to do out there,” Katzman said.
He said some people ask if RDX was discovered in the 90s, why was it only being cleaned up in 2010.
“One of the very important and very rigorous steps is investigations to determine what we call nature and extent. You can’t just guess where the contamination is of the environment. You do a lot of sampling, it’s usually multiple phases of sampling. You continually kind of hone in on your understanding of where contamination is and where it isn’t. So you don’t just go do cleanup like this 1500 yards of soil cleanup, you first find out where the boundaries are and that just takes a lot of time,” Katzman said.
He said the whole area has been studied and the Lab has pretty much constrained where the RDX plume is.
“Because nothing is ever perfect in this line of work, there’s always monitoring done so that if there’s a surprise, if somehow you missed something, you would have the ability to detect an emergent signal of some sort that might tell you, you missed something. So even though we’re calling ourselves done, we have long-term monitoring in place for this site that goes to our regulator every year and if there’s anything that changes, we’ll come back in and complete the work. These should never been considered a done deal,” Katzman said.
In response to a question, Katzman explained that RDX is an organic-based high explosive compound, very subject to natural degradation in the environment in the presence of certain kinds of conditions.
“We’ve actually studied that because it’s really important to understand the environmental fate of a contaminant. We’ve learned that RDX at this site only degrades in anaerobic conditions. In the oxidizing conditions that we have at this site we’re not finding any evidence that it’s going to naturally degrade into the environment,” he said. “It can be treated out of water. Granulated activated carbon is one of the easiest ways to get it out of there. We’ve done treatment in springs where we just pass the water through a small box that had carbon in it and it came out the back side clean.”
Katzman said trying to determine where the contamination of the subsurface is located is a much more complicated process.
“Every time you want to sample it, it requires drilling a well into the ground at great expense and collecting samples, in some cases for years, to get an understanding of what’s there, using that information to drill the next well to further understand what’s there,” he said.
He said there are quite a number of wells in the general area including nine wells down in the regional aquifer and a fair number of additional wells in the perched intermediate groundwater.
“Sometimes we put tracers in the wells – tiny amounts of environmentally-friendly chemical that you can put into a well that moves as groundwater moves and you can watch other locations to monitor for it and that tells you information about the direction the groundwater is moving and how fast it’s moving. We pump on wells and watch other wells to see if they respond. All that gives us information about a very, very complex subsurface that’s about 1,300 feet below ground level,” Katzman said.
He added that work done by DOE and N3B is subject to regulation by NMED with “lots of interaction and lots of documents going to them for approval”.
Only two wells that have contamination that’s above what’s considered our regulatory limit that we’re working to. For RDX that’s 7.02 parts per billion (PPB), so a really tiny concentration is considered the regulatory limit for RDX. There are two wells that have contamination out of all these wells. Several of the others do have small amounts of RDX in them but not above 7.02 ppb.
Probably one of the most important messages that hopefully will take away tonight is that this contamination that we’re talking about at TA-16 is three miles away from the nearest supply wells. Your water supply today is safe. There’s no RDX contamination in the water supply wells. We monitor all of these wells sometimes quarterly and we also supplement what the County has to do for their water supply wells sampling by also funding additional supporting sampling in those wells. There has never been any RDX in those wells.
I know there’s been a lot of concern in the last several months that the aquifer is contaminated. There is contamination in the aquifer but not in the water supply wells.
In response to a question, Katzman said the groundwater moves at different rates but that probably the fastest it might move in this area might be about 20 to 30 feet per year.
Katzman said the next big thing for the project is the Deep Groundwater Investigation Report which will be submitted to NMED in August and will assemble 15 years of work on the project. He said the report will include a very detailed groundwater model – a numerical, mathematical computer model that will consider all the contamination, what’s known about it and how it moves in the environment.
“It will put some uncertainty around that, because uncertainty is a natural part of our work, and project or predict what might happen to that contamination over the next 10 or 20 or 50 years if left alone. If the answer to that is that this thing could really expand and start getting anywhere closer to those water supply wells, that will help us understand what to do to make sure that doesn’t happen,” he said.
“In the regulatory world, the next step to come after the investigation report, if there’s an indication that this contamination could be a problem, is called a Corrective Measures Evaluation which is fancy words for saying, ‘Go figure out what you’re going to do about it’. That’s where additional studies would be done to figure out the best way to tackle it, how you might treat it, by pumping it out and treating it with carbon, how you might try to treat it right in place. There’s a number of ways someone could tackle a problem like this. We’re not there yet. We’re in the process of just figuring out what’s the likely fate of this contamination as we are today,” Katzman said.
In response to a question, Katzman said Pantex site in the Texas Panhandle has been grappling hard with the RDX problem and has been putting a carbon source, essentially sugar, into the groundwater, letting microbes bloom in their abundance.
“There are places that have good experience and if we find ourselves having to go in and do this kind of remediation, that we’ll leverage from for sure,” he said.
Asked about measurements from Well R-69, Katman said preliminary measurements are in the 20 ppb range. He said the well is going to be sampled really for the first official time in the next couple of weeks so everyone should stay tuned for those results.
“Those very first samples are often erroneous because of a number of factors so the samples coming up in the next several weeks will be much more reliable. Early samples don’t always show what the stable concentration is there,” he said. “You might drill through some contamination that’s above the water table and drag it down with you. If it’s metals contamination, you might in the process of drilling grind up rocks that release a little of that metal naturally.”
Katzman said the initial samples weren’t exactly collected with the official system but were collected at the end of aquifer testing.
“We all know to consider those as preliminary data and whenever someone asks what’s in R-69, our best answer is, ‘I’ll tell you after we see two or three rounds of data being stabilized’. The official round of the official sampling system will occur over the next two or three weeks and then we’ll sample probably monthly after that. Depending on whether those results are stabilizing, or whether they’re still bouncing up and down, we’ll know how much confidence we have in the results,” he said.
The latest level at Well R-68 was about 14 ppb which is twice the New Mexico tap water screening level, he said.
Moving on to the Chromium Project, Katzman said the plume is in the same water table but at about 1,000 feet. He noted that through some significant years of study, it was determined that the original significant source of the chromium was a power plant as well as some other minor sources in the area.
Katzman said potassium dichromate was put into the cooling system of the power plant to keep it cool.
“Basically the chromate chrome-plated the plumbing just like it would your bumper to keep it from corroding. It was standard practice at the Laboratory from 1956 to 1972 that that operation took place…. After that people stopped using it because there were environmental issues associated with chromium being released into the environment,” he said.
The plume is in the regional aquifer. It’s about a mile in length and half a mile in width and the thickness is about 75 to maybe 100 feet thick, Katzman said.
“We found evidence a few years ago from a monitoring well called R-50 that concentrations of chromium were increasing. That led the DOE to make a decision to go in and implement what regulatorily is called an interim measure. The interim measure strategy that we’ve chosen is one that uses a series of injection wells that go down into the regional aquifer that we push clean water into. The water is pulled out of the aquifer from that contaminated portion of the aquifer. It comes out contaminated and works its way through piping buried under roadways through a treatment facility, out of the treatment facility and into the injection wells,” he said.
In the treatment facility the extracted water passes over tiny beads that look like caviar and the chromium is exchanged with chromoid before going back into the aquifer.
“The goal of the interim measure is to make sure the edge of the plume doesn’t expand or grow. We don’t want it to expand over towards the County’s water supply well. You can imagine the interest in ensuring that well is protected. We also don’t want the plume to expand down around the boundary with San Ildefonso. You an imagine the DOE and the Laboratory’s interest in making sure that doesn’t happen,” Katzman said.
He said the goal within a couple of years is to get the plume edge back into a much tighter footprint within the Laboratory boundary.
Katzman noted that there has been some very fresh data seen with the pumping and injection process since May 2018.
“We already have evidence that the plume edge has tightened after just a few months of pumping. We’re seeing dramatic decreases in concentration levels of pumping in Well R-50. We’ve sampled Injection Wells 4 and 5 and they’re essentially absent of chromium other than naturally-occurring chromium concentrations. So we are seeing some really early indication that our groundwater models predicted the right fate of the plume behavior. We hope to start moving full bore this summer to see that plume retract,” he said.
Katzman noted that all the data, mapping tools, etc. for the program are available at https://intellusnm.com/