No additional hot spots detected in soil at the edge of Rocky Flats
A batch of soil samples collected from an area near where an elevated plutonium reading was discovered this summer on the periphery of the Rocky Flats National Wildlife Refuge tested well within government-defined acceptable risk thresholds for the deadly substance.
The 25 “step-out” samples had been re-
quested by state health officials in August after a soil grab on the west side of Indiana Street yielded a plutonium reading of 264 picocuries per gram of soil — a level five times higher than the 50 picocuries per gram standard established by the federal government at the time the former nuclear weapons manufacturing plant was cleaned up.
The latest samples, each of which was tested twice using different methods to detect the radionuclide, topped out at 2.9 picocuries per gram of soil. Those results are similar to dozens of other samples that have been collected on and near the refuge in recent months.
Last month, the U.S. Fish and Wildlife Service, which oversees the Rocky Flats National Wildlife Refuge, released results from 48 samples it had taken inside the refuge’s boundaries that ranged from 0.013 picocuries per gram of soil to 3.51 picocuries per gram — levels that are well below what the federal government has determined would be a risk to human health.
Add to that the 27 soil samples taken by Jefferson County in July on the northern and eastern edges of the refuge, where trail accesses into the refuge are planned. The highest reading in that data set was 14 picocuries per gram of soil.
“Everything they’re finding is what we believed is there,” said Dave Abelson, who heads up the Rocky Flats Stewardship Council. “These are extremely low risk.”
But Rocky Flats detractors who remember the noxious history of a facility that for 40 years manufactured plutonium triggers for the nation’s nuclear arsenal and left behind a legacy of secrecy and contamination say the lowertrending readings from recent soil samples don’t vindicate the 6,200acre refuge northwest of Denver of its sordid past.
A consortium of community groups is suing the U.S. Fish and Wildlife Service in an attempt to close the refuge to the public, raising the prospect of health risks from potential exposure to residual contaminants. Rocky Flats officially opened in September 2018 after years of testing and remediation.
There also has been an outcry against a planned four-lane highway, dubbed the Jefferson Parkway, that would run along the eastern edge of the refuge. It was in the parkway’s proposed alignment that the elevated plutonium sample was found. A parkway official told The Denver Post on Wednesday that no further action would be taken with the construction of the roadway until all soil samples already collected have been analyzed and reported — likely by year’s end.
“The public needs to know that plutonium particles are mixed in with the soil,” said retired Northern Arizona University chemistry professor Michael Ketterer, who was hired by the Rocky Mountain Peace and Justice Center to double-check some of the soil samples collected this summer. “Can they be kicked up and inhaled?”
According to the Environmental Protection Agency, plutonium emits radioactive alpha particles that are not terribly harmful outside the body but can be “very damaging” when inhaled, causing cancer and lung disease. The state of Colorado states that the larger the dose of plutonium in the body, the greater the toxicity.
It’s that dose that is at the heart of the dispute over how hazardous contamination at Rocky Flats might be. Ketterer said even if the results from recent samples are well below the cleanup standard, they also are well above the background level for plutonium in Colorado.
According to the Agency for Toxic Substances and Disease Registry, the average concentration of plutonium in surface soil from fallout ranges from 0.01 to 0.1 picocuries per gram.
“There’s a risk associated with these particles that are out there that need to be addressed,” Ketterer said. “This is all about erring on the side of caution.”
But Abelson countered that recreational use of Rocky Flats is all about properly recognizing and managing risk. Aside from the elevated reading of 264 picocuries per gram of soil announced in August, all other samples on and around the refuge have shown that exposure risks there are not a health concern.
“Everyone wants to focus on one data point, but what we’re hearing from the regulatory agencies is that’s not how it works,” he said. “The refuge has been extensively tested — it shows that plutonium levels are extremely low. And there’s an extremely low risk to visitors.”
Lindsay Masters, environmental protection specialist with the Colorado Department of Public Health and Environment, told The Denver Post that the elevated reading appears to be an “outlier” given all the other results collected on site. Her agency said during the summer that there was no immediate public health threat from the elevated reading, but that health officials want to see results from all the samples collected in the parkway corridor.
“… We await the complete soil sampling results from the parkway’s approximately 250 other soil samples, which are set to be completed by the end of 2019,” she said.