When news broke this summer that a soil sample near the eastern edge of Rocky Flats National Wildlife Refuge had an unexpectedly high reading for plutonium, it threatened to shatter the scientific consensus that the refuge was safe for visitors and workers. Fortunately, developments since have been uniformly reassuring.
The scientific judgment may have taken a glancing blow, in other words, but it remains intact. A single soil sample registering 264 picocuries-per-gram, or five times the cleanup standard established for the Rocky Flats site, must be taken seriously. But if it is a unique or exceptionally rare finding wildly out of step with other readings, then there is little justification for revising our attitude toward safety at the refuge.
So far that is the case. Earlier this month, officials released results from 25 other soil samples taken near the spot of the elevated reading. The highest came in at 2.9 picocuries per gram of soil, far below the standard of 50. (For what it’s worth, a picocurie is one-trillionth of a curie, which is a unit of radioactivity.) And those were only the latest soil samples this year with innocuous readings.
As The Denver Post’s John Aguilar reported recently, U.S. Fish and Wildlife Service and Jefferson County each released test results in recent months — totaling 75 soil samples taken in and on the periphery of the refuge — and not one was anywhere near the standard.
There are two related but separate issues at play. The first is public safety at the wildlife refuge, established in 2007 on the buffer zone of the former Rocky Flats nuclear weapons plant northwest of Denver. And the other is the prospect of constructing Jefferson Parkway, a four-lane highway planned for the eastern edge of the refuge where the higher reading was taken, with all the disturbance of soil that work will entail. Many other soil samples from the parkway’s path will be analyzed, with results expected by year’s end. If the higher reading was not an outlier after all, officials may decide to reassess the project.
It’s important to remember, meanwhile, that the plutonium readings taken this year are by no means the first. During the cleanup of Rocky Flats in the 1990s through 2005, literally thousands of readings were acquired from soil and water samples in and around the site under the direction of federal and state officials. Many readings in the buffer zone were no higher than natural background radiation values. Those that actually were higher tended to be concentrated to the east of the plant (which is where this year’s contaminated sample was found).
Nevertheless, the upshot of those collective readings after cleanup, according to the state health department’s website, is that the “average concentration of plutonium in the surface soil of the refuge portion of the site is 1.1 picocuries,” which “equates to an excess cancer risk below one in a million for a refuge visitor or worker, or even a resident.”
In other words, plutonium in the refuge could result in something less than one more case of cancer than might have been expected among 1 million persons (who would have to spend a great deal of time there) — an infinitesimal risk considering that nearly 40 percent of us are fated to be diagnosed with cancer at some point and one in five to die from it. A one in 1 million additional risk doesn’t even budge the lifetime cancer odds. It’s the last thing refuge visitors should have on their minds.
The public’s sense of risk is often skewed by exposure to selective news coverage and political posturing that fails to put an alleged hazard in context. But since risk is an unavoidable part of everyday human life associated with many common activities, context really is everything.
For example, according to the National Safety Council, Americans have a 1 in 114 chance during their lives of dying in a motor vehicle crash and a 1 in 127 chance of dying from a fall. Even a lightning strike checks in with a 1 in 162,000 lifetime risk.
Does anyone stay up at night worrying about these things? Maybe it’s time we adopted a similarly mature attitude toward far smaller dangers.
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