N3B Los Alamos Runs Robust Groundwater Monitoring Program For DOE-EM LANL Legacy Waste Cleanup

A rafting trip to collect water samples from the Rio Grande and tributaries to White Rock Canyon is part of a robust groundwater monitoring run by N3B-Los Alamos. Photo Courtesy N3B

Groundwater Monitoring Program manager Keith McIntyre, left, and technical lead David Fellenz point out landmarks along the Rio Grande during an interview with the Los Alamos Reporter at the White Rock overlook. Photo by Maire O’Neill/losalamosreporter.com

Taking water from a spring for sampling. Scientists wear special protection from rattlesnake bites. Photo Courtesy N3B


N3B Los Alamos is the legacy waste cleanup contractor for the Department of Energy Environmental Management Field Office at Los Alamos National Laboratory. Although N3B is in its fifth year at LANL, many local residents are not aware of their work priorities both throughout LANL property and offsite throughout the area including on Santa Fe National Forest and Pueblo de San Ildefonso land, and particularly in and around the Rio Grande.

Asked what they believe N3B’s cleanup priority should be, many people indicated their desire to see contaminated material removed from LANL and the community as quickly as possible, however many others want the groundwater protected to make sure contaminants from LANL do not enter the Rio Grande or negatively impact people, the ecology and the environment.

To that end, some 4,000 water samples are collected each fiscal year under a robust groundwater sampling program run by N3B Los Alamos that includes monitoring of the Rio Grande in White Rock Canyon as well as gathering samples of several tributary canyons that run into the river.

The Los Alamos Reporter met recently with Keith McIntyre , Groundwater Manager and David Fellenz, the groundwater project’s Technical Lead. Looking down from the White Rock Overlook, the two men pointed out the Buckman Diversion on the far side of the Rio Grande.

McIntyre got into a little detail about the program’s annual trip down White Rock Canyon to sample springs and base flows.

“We come in at Buckman and float down and start sampling close to the Overlook. The last sample is at Frijoles Canyon and then we float all the way down to Cochiti Lake. It’s a three day trip – 15 miles that we cover,” he said.

Fellenz has made the trip downriver more than a dozen times. He said it’s always a good time but always a lot of work.

Sampling consists of a total of 27 springs and base flow locations. The samples require a bit of a hike, so even though the scientists float the river, when they stop at a location, they hike to the individual springs.

“Everything that we use to sample we carry in with us. If the spring is flowing enough we can actually collect the water straight from the source. Otherwise we use a little battery-operated pump to pump the water into the containers,” Fellenz said.

McIntyre said on the last trip there were three teams of four and they used a professional guide service. There were two people each raft and then a number of rafts just carrying equipment and ice chests.

“We had a total of 17 rafts. It was quite the flotilla,” Fellenz said.

The team looks for radionuclides such as tritium, uranium, plutonium and radium, as well as metals, high explosives and PFAS chemicals.

“We are looking for a number of different constituents. We are looking for potential sources of Lab contamination that are expressed at the springs. In the over 20 years that we have been sampling this we have not had any exceedences that are related to Lab waste. We have seen some elevated metals. Mostly iron and manganese and that is because of the basalt we have around here so the springs that discharge at the interface of the basalt where it meets the underlying strata, there we typically see elevated manganese and iron, just based on the geology,” McIntyre said. “All the time we’ve been doing this, the water we’re seeing at these springs, by the time it makes it down here is very clean, high-quality water that’s being discharged into the canyon.”

The team is looking at the samples they collect for basically anything that would have been used at the Laboratory or would have been used just for commercial purposes.

“We’re not seeing any of that expressed at the springs when we sample them,” McIntyre said.

Results of every sample taken by the Groundwater Monitoring Team are available to the public on the Intellus NM website (https://www.intellusnm.com/), which stores environmental date provided by N3B and the New Mexico Environment. Literally millions are retrievable and users can avail of filters and maps to access specific records. It also provides the ability to compare LANL and NMED data or review trends over time and across locations.

NMED personnel joined the N3B team for the last Rio Grande trip and collected co-samples. Fellenz said NMED has had folks on the trip for the 12 years he has been doing it and even before that.

“The Rio Grande trip has the most work of any sampling event during the year. We were able to collect from 20 locations this year. There were a few that we were not able to sample from. A few were cancelled because the river was actually a little bit higher this year. Some of the springs are right at river level and the river was above the springs so we couldn’t sample those. One was cancelled due to poison ivy – we didn’t want to send people into a location where they could potentially come in contact with poison ivy. There were a few base flow locations that were dry so there was no water to sample. We collected 128 samples from the 20 locations. My fun statistic is that we sampled 75 gallons of water total which is what we collected from that sampling event,” Fellenz said.

He said the team didn’t find any surprises from the analytical side.

“Everything we were looking was background levels, which is what we were expecting. One of the surprises this trip is that right before we were going to go in October, typically when we do that the river is lower and we can get to all the springs. We were a little surprised that the river was as high as it was this year that some of the springs were underwater so they were not sampleable,” Fellenz said.

Asked about the professional rafting guides, Fellenz said the scientists were doing their own rafts when the sampling first started.

“Part of the reason we go with a professional guide service is that they have experience in this type of environment. They also have first aid response because there’s a lot of potential for first aid events. And the sampling days are typically 10-hour days so I’m not going to lie – it’s really nice to come into camp and have someone else prepare me a dinner,” he said.

McIntyre said it takes about a week before the trip to prepare all the bottles, ice chests and other equipment. He has been working on the Groundwater Monitoring Program for about 4 ½ years, having relocated from California where he had been in environmental work for 10 years – putting in wells, sampling wells and soil.

Fellenz’s background is in aqueous geochemistry. He has been working at the LANL site for 12 years, initially doing field sample collection for all the wells.  He says he still does that aspect of it but not quite as much, but he has a very intimate knowledge of all the locations.

When they are not on the Rio Grande trip, McIntyre said the program has a full complement of monitoring well sampling to do all over the Lab that keeps them busy all year round. They have a list of campaigns that they work on and rotate through each month.

Fellenz said last time he checked there were 204 locations to be sampled.

“We sample in the chromium area monthly and some of the other watersheds based on where they are and what contaminants we’re concerned about. We sample either quarterly to annually. We’re working right now on some of the RDX sampling we do on a quarterly basis. We have seen elevated levels of RDX. Right now we’re sampling to understand the nature and extent as well as if there are any trends out there. Things seem to be pretty static in terms of what we’re seeing as levels,” he said.

Fellenz said N3B samples alluvial wells, which are very shallow – about 20 feet or so right about the surface. 

“Below that there’s the intermediate zone which can range from 100 feet to 500-600 feet. Below that is our regional aquifer. The RDX is mostly concentrated in that intermediate alluvial zone. We are definitely monitoring it to understand where it’s going and any impacts it might have in the future.  So that is very much on our radar,” he said. “It’s very transparent what we do out here and all the results are available for the public to see. Sometimes I think it gets lost that the data are available and we want to share that to show that we are being good stewards up here for the environment.”

In addition to monitoring groundwater for contamination and controlling contaminated storm water linked to LANL, N3B is also treating a groundwater plume that contains elevated levels of hexavalent chromium and investigating a plume of Royal Demolition Explosives (RDX). Both plumes are in the regional aquifer beneath LANL.

To learn more about the chromium project, go to https://n3b-la.com/wp-content/uploads/2022/10/Chromium-Plume-Fact-Sheet_21.11.02.pdf

To learn about the RDX Program, go to https://n3b-la.com/wp-content/uploads/2022/10/RDX_Fact-Sheet_21.11.02.pdf

Looking towards the Buckman Diversion on the far site of the Rio Grande from the White Rock Overlook. Photo by Maire O’Neill/losalamosreporter.com

The N3B’s groundwater monitoring trip down the Rio Grande from Otowi Bridge to Cochiti Reservoir to collect water samples is fun but lots of work. Photo Courtesy N3B