Radioactive waste has been contaminating the groundwater below a uranium tailings dumpsite just outside Durango for at least a decade, and still, after all these years, U.S. government officials don’t have an explanation why.
The reported leak has watchdogs on legacy uranium issues questioning whether the 23-year-old disposal site, about 3 miles up County Road 210 southwest of downtown Durango, is showing signs of aging – a trend many uranium repositories across the U.S. are experiencing as time wears on.
“This site appears to be releasing uranium in an unexplained way, has been for decades and there doesn’t appear to be an effort to better define the problem, much less remediate it,” said Paul Robinson, research director with the Southwest Research and Information Center.
Officials with the U.S. Department of Energy, which manages the Durango disposal site, maintained in interviews for this story that the reported high levels of uranium in one of the groundwater tables below the disposal cell does not pose a risk to human health or the environment.
But DOE site manager Jalena Dayvault recognized the leak is a problem that warrants time and energy to figure out. In November 2018, for instance, a monitoring well in the water table noted the highest spike of uranium since it was installed in 2002.
“We’re continuing to work to understand what’s happening,” Dayvault said. “But responses take time.”
A massive pile of uranium tailings sat alongside the west banks of the Animas River, in an area that’s now the Durango Dog Park, for years as a part of the U.S.’s race to create the first atomic bomb.
It wasn’t until the 1970s, however, that health risks and environmental concerns took hold surrounding the radioactive waste pile, which had grown to 1.2 million cubic yards, enough to fill nearly 400 Olympic-size swimming pools.
Congress in 1978 ordered toxic sites across the country be cleaned. But figuring out what to do with the massive dump was no easy task, said Greg Hoch, the city of Durango’s longtime planning director, now retired. It pit neighbor against neighbor and put the town at a contentious crossroads.
In one instance, a Molotov cocktail was hurled at a sign warning of the radioactive dangers of the tailings. No one was ever caught, but a report from The Durango Herald at the time speculated it was likely a reaction to the fear some merchants had of the stigma the sign brought to the town.
“Like everything in Durango, there’s no one school of thought,” Hoch said. “Some people wanted it moved, others said don’t waste the money. But like almost all issues in the public arena, you end up somewhere in the middle.”
It wasn’t immediate health risks that prompted a call to move the tailings, Hoch said. Instead, there was a far larger concern that an earthquake or smaller seismic activity from the robust oil and gas drilling in the region at the time would cause the pile to fail and fall into the Animas River.
Several options were evaluated, but ultimately, it was decided to haul the tailings over Smelter Mountain. From 1986 to 1991, tens of millions of dollars were spent to move the pile 3 miles, and the site was considered closed in 1996.
“The fact there’s contaminated groundwater might mean the cell is not working as originally planned,” Hoch said. “Obviously, someone may have made a mistake.”
The 60-acre disposal cell just outside Durango, surrounded by more than 82 warning signs around its boundary, contains an estimated 2.5 million cubic yards of contaminated material, including the mill tailings and other radioactive waste associated with local uranium mining.
The uranium tailings are buried under 7 feet of material in layers meant to control radon exposure, erosion and shed storm runoff. The top of the cell is covered with native plants and grasses, and the sides are armored with rock riprap to further prevent erosion.
The bottom of the cell is lined with 2 feet of thick clay. Seeps were not unexpected, DOE officials said, but one monitoring well in the groundwater underneath the liner has researchers scratching their heads.
As part of its long-term management of the site, the DOE is required to test the groundwater monthly for three potentially dangerous chemicals: molybdenum, selenium and uranium.
The DOE has three “compliance wells” in the upper-most aquifer below the tailings, which have not exceeded health standards. As a result, the disposal site is not violating any standards and doesn’t require immediate attention, per department rules.
As an added safety measure, several monitoring wells were installed in other groundwater tables, which do not influence the site’s compliance status. It’s one of these wells drilled in 2002 – Well No. 0618 – that has shown rising levels of uranium since 2007, drawing the department’s attention.
During the most recent sampling report, Well No. 0618 showed uranium levels at nearly 0.2 milligrams per liter. For reference, the site-specific standard is 0.077 mg/L and the drinking water standard is 0.03 mg/L.
At this point, it’s all speculation about why Well No. 0618 is spiking. Dayvault said the DOE drilled several other wells into the alluvium to better understand the geological makeup of the area.
An evaporation pond nearby was removed in 2017 that caught storm runoff, which could be one reason, she said. Or maybe there’s a spot in the subsurface of the cell that hasn’t stabilized. The worst-case scenario – a breach in the bottom liner of the cell – has yet to be investigated.
Dayvault said the department is looking into whether the removal of the evaporation pond is the cause, with an investigation that will try to correlate factors like rain and snowmelt with uranium spikes. Later this year, the department hopes to bring in LiDAR, an enhanced form of radar detection, as well.
If that study comes back empty, attention will be turned to the state of the liner, she said.
“We want to make sure whatever we do, it’s a long-term fix,” Dayvault said. “It’s of interest to all of us.”
The alluvium in question is about 60 feet below the cell. The DOE maintains the waters are not used or connected to nearby water sources, so it doesn’t pose a risk to human health.
Geological studies, the department says, have shown no proof the alluvium is connected to Lake Nighthorse, which is about a mile away. Attempts to reach the Bureau of Reclamation, which tests water at the lake, were unsuccessful this week.
But where the water in the alluvium ends up is yet another question stumping the DOE. The department recently had a geologist walk the drainage looking for seeps, to no avail. Studies have shown the water table is connected to the Animas River, which is about a mile away, but the department is unsure how long it takes water to reach the river.
Despite the monitoring efforts of the DOE, the department has received criticism it is not treating the situation of Well No. 0618 with more urgency.
“It doesn’t matter to me whether it’s a ‘compliance well’ or not,” said Travis Stills, an attorney with Energy & Conservation Law. “If you can’t explain what’s going on with it, it’s a serious problem.”
Stills said groundwater contamination is nearly impossible to clean up, so it’s important to be proactive before a potential disaster strikes. And, he said if levels at Well No. 0618 are an early warning sign the cell’s liner is failing, that needs to be addressed before a much larger contamination problem occurs.
“There’s a lot of history of liners failings (in other sites across the U.S.),” Stills said. “There is no good place for uranium milling waste to go, but some are less bad than others. And this site is terrible.”
Stills said the area where the uranium tailings are located experiences a good deal of geologic activity, which will exacerbate crack and erosion issues. The DOE, for its part, says seismic activity is not an issue at the Durango disposal site.
Robinson, who works for Southwest Research and Information Center, a nonprofit that works with communities dealing with lingering uranium issues, also took issue with what he called the DOE’s slow and seemingly unalarmed response to the groundwater contamination.
“The typical task when you have contamination is to find the source, and where it’s moved,” he said. “That’s an action that’s long overdue. A lack of response … is an indication of a lack of effort.”
La Plata County Commissioner Gwen Lachelt said the county has raised concerns with the DOE about the rising levels of uranium in the groundwater, calling for more monitoring wells to better understand the issue. But the department has been unwilling to do so, she said.
“We need DOE to be a cooperative partner in addressing our shared issues,” Lachelt said.
The lasting impacts of legacy uranium mining is something many communities across the West have to deal with, likely forever, said Dayvault. A little more than 20 years after the construction of the Durango disposal site, changes are happening, some expected, others not, she said.
When questioned if the supposed leak into the groundwater below the disposal cell warrants a more robust response, Dayvault said no.
“The monitoring we’re doing is commensurate with what the site needs,” she said. “If we needed more, we’d do it.”
The DOE considers the site in Durango one of the most extensive and successful cleanups in the country. Dayvault said the expected lifespan of the tailings cap to be at least 200 years. But with proper maintenance, and leaving good tracks for future operators, it could be thousands of years, she said.
“The U.S. was the first to embark on uranium cleanups, so we’re learning a lot over time,” Dayvault said. “We’re here to make sure contamination is controlled, and we’ll be here forever, doing what we do. Our mission here is indefinite.”
jromeo@durangoherald.com
