EPA Region 6 Administrator Dr. Earthea Nance, second from left, chats with, from left, Eric Chavez, Field Representative for Sen. Ben Ray Lujan, Nance, State Rep. Susan Herrera, and Matt Miller, Field Representative for U.S. Rep. Teresa Leger Fernandez at Wednesday’s meeting in Espanola. Photo by Maire O’Neill/losalamosreporter.com

Santa Clara Pueblo Gov. J. Michael Chavarria, left, and Lt. Gov. James Naranjo at Wednesday’s meeting with NMED and EPA officials in Espanola. Photo by Maire O’Neill/losalamosreporter.com

Rio Arriba County Manager Lucia Sanchez speaks with Espanola Mayor-Elect John Ramon Vigil Wednesday at the EPA/NMED meeting in Espanola. Photo by Maire O’Neill/losalamosreporter.com

BY MAIRE O’NEILL
maire@losalamosreporter.com

New Mexico Environment Department Deputy Sec. Rebecca Roose and Dr. Earthea Nance, the new Regional Administrator for the EPA Region 6 Office joined representatives of the City of Espanola, Rio Arriba County and Santa Clara Pueblo last week in Espanola to discuss the North Railroad Avenue Plume (NRAP) Superfund Site on land within the City and the Pueblo. A site tour had been planned but snowy conditions in the area caused the walk around to be canceled.   

Anthony McGlown, Superfund Remedial Action Team Leader with the New Mexico Environment Department’s Ground Water Quality Bureau brought group up-to –date with a presentation on the NRAP Site which consists of a groundwater contaminant plume of the solvents tetrachloroethylene (PCE) trichloroethylene (TCE) cis-1,2-dichloroethylene (DCE) and trans-1,2-DCE.  

The solvents were used by the Norge Laundromat and Dry Cleaning operation that is identified as the Source Area, from 1970 to 2007. Those solvents were commonly used by dry cleaners in the past and there’s still some use of them today. 

McGlown said the contamination was discovered by NMED’s predecessor agency in 1989 in two municipal supply wells. 

“In cooperation with EPA, the Pueblo and our local partners NMED has been the technical lead on the cleanup and investigation efforts since the contamination was discovered. The site was listed on the National EPA’s priority list of Superfund Sites in 1999 and the remedy was selected by 2001 with agreement from the state and the Pueblo. It was altered slightly in 2008 to remove some unnecessary features in the Source Area only,” McGlown said.

He explained that the remedy consists of bioremediation, which is an injection of material to enhance and feed off what are naturally occurring biological and chemical processes that break the contaminants down eventually into a harmless end product. Part of the process for selecting the remedy included a feasibility study that went through options such as a pump and treat system, and looked at the expected cost and duration of the remedy. 

“Bioremediation was settled on here as the most effective means of dealing with the plume. Construction began in 2008, the EPA declared the system operational and functional in 2009 and NMED has been performing bioremediation injections in the Shallow Zone of the plume since,” McGlown said.  

The RPA has funded the project for the last 10 years and now the project is being turned over to NMED to fund 100 percent for the remainder of the cleanup which is expected to take a total of 30 years from when it was initiated. 

“We are ahead of schedule on part of this plume (the Shallow Plume) which has largely been cleaned up. A small area of contamination remains at the Source Area only,” McGlown said.

The Shallow Plume lies about 6 feet to 30 feet below ground surface, and when cleanup began, it extended three-quarters of a mile Into Santa Clara lands all the way to the Rio Grande. 

“Today, that plume is almost entirely gone. We have successfully remediated all of the Shallow Plume which is the largest risk driver at the site,” McGlown said. 

The Deep Zone Plume, the Calle Chavez Plume discovered in 2017, is not a Superfund Site. It was traced back to another dry cleaning business in Espanola. That plume, according to 2021 data, is located between 45 feet and 265 feet below ground surface and is being addressed through one of NMED’s cleanup programs through the responsible party, McGlown said. He noted that NMED is not doing nearly as much bioremediation. He said there was originally a treatment compound in the Source Area with a pretty comprehensive and complex recirculation system, which is now mostly for storage. Another system was mostly removed in 2019 because it was no longer needed.

The system in the Source Area was historically connected to injection and extraction wells to pull out contaminated groundwater, add the bioremediation amendment, and recirculate to clean up the plume. The system to the south was simpler and that was along Santa Clara Bridge Road,” McGlown said.

“What’s mostly left now are monitoring wells. We’re injecting a little bit at this point to catch a small area that remains right next to the dry cleaner building itself. Contaminant concentrations have continued to decrease since the most recent injections in 2021 and no additional Source Area injections are needed until 2023,” McGlown said. “With what we have left today, we’re seeing continual decrease in the concentrations from what was one of the highest I’ve seen at Superfund Sites in New Mexico at a concentration of over 40,000 micrograms per liter. Today we have three wells that are two orders of magnitude lower than that and it’s just those three wells that are exceeding EPA’s level of 5 micrograms per liter.”

He said he is really happy with the progress in the Shallow Zone taking a plume area of 60 acres down to an area of the footprint of the building itself today.

“We don’t have to inject that often anymore and we have moved to a new injection amendment that’s still facilitating our remediation but it has more of a slower release mechanism that allows us to inject and then it’s effective for a longer period,” McGlown said.

The outlook is more long-term on the Deep Zone cleanup.

“We started injection in 2008 and there was some difficulty getting our amendment into the Deep Zone for a few reasons, one being that it’s deep and it’s rather expensive drilling down another 250 feet. The amendment that we were using, which is an emulsified vegetable oil, does not like to get out very far from the well and into the deeper groundwater zones,” McGlown said. 

 This prompted NMED to stop injections in 2012. They also wanted to focus on the Shallow Zone which was more of a risk because it was close and also because of air vapor inclusion.

“Now that the shallow zone is done, we want to shift our focus to tackling the deeper contamination that is more of a long-term prospect. As part of that we completed a pilot test in March 2020 with the new amendment material and the initial results from that which occurred at the Plaza were that the concentrations in our test well dropped by over 70 percent in just one year after the new amendment. That tells us it’s working right in our test area and we were also able to sustain injection rates that were over 10 times higher than what we were able to do in the historic area. So those are really great signs that this is going to work. Based on that, we have proceeded with full-scale injections over the plume,” McGlown said. 

Flow in both the Shallow and Deep Zones is heavily influenced by the Rio Grande. Part of the reason the contamination in the Deep Zone is not directly beneath the Shallow Zone is that it was pulled by the pumping models for decades.

“All the contamination in the Source Area got pulled into the Deep Zone by the pumping of the Bond Well and the Jemez Well, which are City of Espanola drinking water wells where contamination was first found in 1989. That’s why it is where it is laterally and also 165 feet deep from the historical pumping of those wells” McGlown said. “That’s what we see in sites across the country these days; oftentimes there is historical municipal pumping that indicates where the plume might be. The municipal wells are about 260 feet deep and the contamination went about as deep as the wells. Those wells are inactive. Once it gets down there, it stays until we do something about it.”

McGlown said NMED’s consultant just finished their conceptual site model looking into the details of the geology and especially what’s going on down in the deeper intervals so that NMED can continue to refine the injection strategy and the injection amendments to make sure they’re using the ones they have as efficiently as possible. 

McGlown said the work is fully-funded through 2023. NMED may be going back to the legislature to seek additional funding, he said, and will be determining between now and then how much additional funding they need at that time.

“This is not the first site that has gone into operations and maintenance and was funded by the state and we’ve never had a problem securing funding. We are continuing to continue injections in the Deep Zone. We are working on the details with our site contractor but we’re thinking that it will be late 2022 or early 2023. Some areas that we’ve injected into recently we won’t be doing again just yet because there’s a slow release component so we don’t need to inject every single year. We will continue to inject in certain areas to continue to capture the core of the plume.”he said. “Timeframe-wise, it is pretty common for Superfund sites of this type of groundwater cleanup of contaminants to have about 30 years as the goal.”

McGlown said, right now NMED is just revamping the Deep Zone injection making that their focus.

“We only have one year of monitoring data which is not enough to release any kind of statement about timeframes but in the coming meetings over the next year or two, I’m hopeful that we will have more data showing trend lines and actual data to support the progress of the remediation,” he said. 

One of the major reasons for focusing on the Shallow Zone was indoor air vapor intrusion, McGlown said. 

“ The contaminants that we’re dealing with degrade into volatile organic compounds.  in groundwater they can evaporate from the shallow groundwater and potentially accumulate in overlying structures. NMED has monitored occupied structures near the Source Area for potential vapor intrusion since 2008. The knowledge pertaining to vapor intrusion is relatively young compared to groundwater and I am happy to see that we have been monitoring these buildings at least annually,” he said. 

The air monitoring is not just for PCE but also for the breakdown products. 

“I’m happy to say that in the more than 10 years that we’ve been monitoring these buildings, though occasionally we have detected levels of contaminants in some of them, they’ve never been high enough to warrant a response action. As the cleanup continues we expect the vapor intrusion levels to drop over time but we are committed to continuing that monitoring for as long as it takes to make sure these occupants are protected,” McGlown said.