When the Jefferson Parkway Public Highway Authority (JPPHA) and other groups launched a soil study this May, with the goal of testing the Rocky Flats area for excess nuclear waste that could be …
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The curie is a standard measure for the intensity of radioactivity contained in a sample of radioactive material. A picocurie is one-one trillionth the radioactivity of one gram of radium.
It was named after French scientists Marie and Pierre Curie for their landmark research into the nature of radioactivity.
— Source: U.S. Army Corps of Engineers
When the Jefferson Parkway Public Highway Authority (JPPHA) and other groups launched a soil study this May, with the goal of testing the Rocky Flats area for excess nuclear waste that could be stirred up during construction of the Jefferson Parkway, groups were “not expecting any surprises,” said Roy Laws, an environmental engineer with Jefferson County Public Health, “but you don’t know until you get the samples.”
“No surprises” would would have meant that each sample taken by consulting firm Engineering Analytics would contain no more than 50 picocuries per gram, or pCi/g, of plutonium. This number was the standard set after the Environmental Protection Agency (EPA) and FBI raided and shut down the Rocky Flats facility in 1989 to ensure contamination was disposed of.
Critics of the Jefferson Parkway, a toll road that is slated to partially run along the eastern edge of the Rocky Flats buffer site, say its construction could stir up buried contaminants, causing harm to anyone who inhales the dust.
The JPPHA helped launched the study to address these concerns and confirm the parkway would not put nearby individuals at risk. But on Aug. 16, JPPHA Executive Director Bill Ray alerted the Colorado Department of Public Health and Environment (CDPHE) that one sample had registered 264 pCi/g, or five times the cleanup standard, according to a community letter from the CDPHE.
The sample was taken from the west side of Indiana Street, 1.3 miles north of 96th Avenue and just south of the Great Western Reservoir.
A second test run on a different portion of the same gram of soil — the first tested just a portion of the sample — showed only 1.5 pCi/g, said CDPHE Environmental Protection Specialist Lindsay Masters.
Analyzers are now completing the study to help JPPHA and CDPHE determine what the elevated levels mean for area risk, with the authority planning to “follow (the CDPHE’s) lead on next steps,” Ray said. “Public safety is the number one priority for the Jefferson Parkway.”
Jennifer Opila, CDPHE division director of the Hazardous Materials and Waste Management Division, said the CDPHE will work with the EPA and Department of Energy to determine the best course of action.
“We don’t believe there is an immediate public health threat,” she added.
As for what the 264 pCi/g reading means for safety, “a single sample doesn’t give a complete answer,” said Dr. Kathryn Higley, professor and head of the School of Nuclear Science and Engineering at Oregon State University.
Other factors, such as the size of the individual plutonium particle, are important for the risk calculation, she said.
Were it just that gram of soil that was contaminated, the radiation would be “very, very far below the level at which radiation risks have been actually observed in humans,” she said.
With the lingering question of whether similar levels will show up in other spots, some community groups, including the Rocky Flats Downwinders, also seek more info.
“We believe more analysis needs to be done. Construction needs to stop in the area and more soil testing needs to happen in and around the Rocky Flats Wildlife Refuge,” said the group’s director, Tiffany Hansen. “We are extremely concerned about the health impacts of inhaling, eating or getting a hot particle in the body.”
As the groups continue to evaluate what the samples mean, the CDPHE has invited the community to reach out with questions.
“Right now there is a lot left unanswered,” the letter said. “We will continue to review additional sampling information and do everything possible to ensure you are informed.”
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