Forty-eight soil samples taken inside the Rocky Flats National Wildlife Refuge in June revealed no elevated levels of plutonium, according to results released by officials with the U.S. Fish & Wildlife Service on Friday.
The results follow last month’s news that a significantly elevated plutonium reading had been detected in a single soil sample collected just outside the eastern boundary of the refuge along Indiana Street.
That sample came in at 264 picocuries per gram of soil, more than five times the cleanup level established by the federal government for residual plutonium when it cleaned up the site of the former nuclear weapons plant 16 miles northwest of Denver.
The finding triggered the Colorado Department of Public Health and Environment to issue a letter to communities near the refuge saying it was “taking the sample result seriously because it is much higher than previous samples in the vicinity and higher than the cleanup standard.”
But health officials also said that toxicologists at CDPHE “do not believe there is an immediate public health threat” from the high reading.
The 48 samples taken in late June on behalf of the Fish & Wildlife Service cover a 4-mile stretch inside the refuge where trails are being planned that would connect yet-to-be-built access points into and out of the refuge on Indiana Street and Colorado 128.
The readings for plutonium across the 48 samples ranged from 0.013 picocuries per gram of soil to 3.51 picocuries per gram of soil, levels that are well below what the federal government has determined would be a risk to human health.
Readings for contaminants like uranium and americium were also found to be well below the threshold for health concerns, the report concluded.
The samples were collected and analyzed by Fort Collins-based Engineering Analytics, the same company that found the elevated sample along Indiana Street. The firm issued a 518-page report detailing its findings.
“The new soil sampling results are consistent with previous conclusions and recommendations by state and federal public health experts, indicating that the area is safe for public use,” the Fish & Wildlife Service said in a press release Friday.
Dave Abelson, who heads up the Rocky Flats Stewardship Council, said Friday’s news “confirms what we’ve always known” in regards to what historic soil sampling has shown about any contaminants left behind after a 10-year cleanup of the plant: There is no evidence that human health is at risk in the refuge.
“It’s new sampling that reaffirms older sampling of residual contamination levels along the refuge trails,” he said. “We have a lot of new samples — and we have one outlier.”
But Abelson said he’s still waiting for state health officials to fully assess the area where the hot sample was found before coming to any definitive conclusions about health risks.
Several environmental groups have sued the Fish & Wildlife Service contending that the refuge, which opened to the public a year ago, is not safe for recreational use. Those legal challenges are still going through the courts.
But just this week, that coalition told a federal judge through new filings attached to its original lawsuit that the elevated reading disclosed in August “raises questions about the EPA’s determination of safety at Rocky Flats, which is based on Refuge soils meeting cleanup standards.”
Patricia Mellen, an attorney who represents community groups trying to unseal 30-year-old grand jury documents connected to the former nuclear weapons plant, said 48 samples “is a drop in the bucket on a property of this size.”
The refuge covers 6,200 acres, including a 1,350-acre off-limits area in the middle of the property where the nuclear triggers were actually assembled.
Mellen said Friday’s announcement shows the state and federal health officials’ “eagerness to stem the tide of concern raised by the hot sample disclosed in August.” She is calling for further sampling at greater depths — “to the depths the construction actually will reach.”
Engineering Analytics sampled to a depth of 2 inches inside the refuge, its report states.
The single elevated plutonium reading disclosed last month stalled plans to build a $250 million tollway, the Jefferson Parkway, along the eastern edge of the refuge. Highway officials are waiting to see if any other soil samples taken along the proposed roadway’s alignment yield concerning levels of plutonium or other radionuclides before moving forward.
Dozens of samples taken inside and outside the refuge are still being tested. Those results are expected to be released in the coming weeks and months.
