Radon: A Different Perspective

The Radon Issue
After reading the very detailed article about radon in the Gazette last Sunday - followed by Mike Biles' and Charles J. Robinove's very thoughtful and accurate letters on Tuesday, Aug. 29 - I decided to weigh in on the discussion to give Mike's and Charles' letters added credibility. 
I have been lecturing about this topic for almost 20 years, ever since Mr. Stanley Watras set off the alarms at the Limerick Nuclear Generating Station in Pottstown, Pa., on his way to work.  A quick check of his house found radon levels off the chart, almost 300 times the EPA action level of 4 picocuries per liter.  That led to a classic EPA quote, "Radon, the environmental problem posing the highest risk of cancer."  That quote seemed so ludicrous and so defied common sense that I started my own research into the problem because I knew that this had to be bad science.
Admittedly, my research was limited to the scientific literature and the few studies that had been done around the world because doing radon research on human subjects is impossible.  Let me start with a little background on radon.  It is the natural decay product of radium, which is in the line of the natural decay sequence from uranium, a naturally occurring radioactive element that has been with us since the planet formed almost 5 billion years ago.  Logic tells us that life on earth has dealt with this background radiation for as long as there has been life on earth. 
That also means that we have adjusted physiologically to that presence of radiation, since it is everywhere on this planet.  I for one do not want anyone trying to lower my radon levels because I enjoy the health that natural background radiation provides.  By the way, 54% of all natural background radiation comes from radon, and 27% comes from all other natural radioactive elements. 
The literature actually showed a couple of classic -- but flawed -- studies about the impact of radon on human health: one on a population of rats exposed to various levels of radon aimed at simulating working conditions for miners; the other studied cancer rates among uranium miners.  The rat studies actually showed longer lives for several populations of rats exposed to fairly high levels of radon and none of the same kind of cancer the miners had.  The miner studies were deeply flawed because only 16 of the 478 miners studied were non-smokers! 
Mike's comments about the international fix to this problem were right on target.  To expand on the Canadian action he mentions, for example, the government there tried to correlate high levels of radon with lung cancer rates in all of their major cities and found just the opposite or no correlation.  In some cities, high radon levels actually showed lower-than-average lung cancer rates.  So, they gave up, changed the action level to 21.8 picocuries per liter, and the problem went away. 
There is an ongoing attempt to scare people about the high levels of radon in Colorado compared to the national average.  Well, there's a good reason for that higher average.  The Rocky Mountains are only about 35 million years old, very "young" on a geological time scale, so the higher natural background radiation comes from the "freshly turned ground" as the Rockies were formed and exposed higher levels of uranium, hence radon.  But, if the average radon levels here are about 17 picocuries per liter, that is still less than the action level the Canadians set. 
Let me put the Colorado average radon level in perspective.  Part of the problem the EPA faces is the "Linear No-Threshold" concept that comes from The Delaney Clause, sponsored by U.S. Senator James Delaney and approved by Congress in 1951.  It simply presumes that the detrimental effects of radiation are proportional to the dose, and that there is no dose at which the effects of radiation are not detrimental.  I often wondered where the EPA got the action level of 4 picocuries per liter.  It turns out that it is the lowest level that can be measured accurately, so the EPA is clearly using The Delaney Clause to make their case. 
Now, along comes a relatively underused concept that has been around for about 100 years, but has not received the attention and credibility it deserves until recently.  The concept is called "hormesis" and is simply defined as the "stimulating and protective effect of small doses of radiation," also called adaptive response.  There have been a number of studies done on Nagasaki survivors with respect to cancer risk verses radiation dose received, and they clearly show that there is a point at which the risk is at its lowest, and that point is not at zero radiation!  In fact, at zero radiation, factoring out the background, the cancer risk goes back up. 
If we carry that over to radon, there is some level of radon background radiation that is optimum for living organisms, and I will bet that that level is not 4 picocuries per liter.  I'm guessing it's somewhere near the "healthy" level we find in Colorado at about 15-20 picocuries per liter.  It's interesting that we have one of the lowest lung cancer rates in America, but that's probably due more to our healthy lifestyle and culture than it is to radon levels. 
I should also comment on Jim Burkhart's response to the Letters to the Editor because I know Jim.  He's a good physicist and great teacher.  I sit on the science advisory board at UCCS and have come to know and respect Jim.  I'm sorry he discounted the two Aug. 29 letters, because I believe both Mike and Charles were on target with their comments.  I take no exception to what Jim presents in terms of distribution of radon levels and the other points he makes.  What Jim has failed to address is the crux of my point:  what is the right radon level for action? 
There is scarce physiological data on the subject, and I'm compelled to believe the hormesis concept because it makes good logical sense and is backed by decent scientific studies.  No one is going to convince me to spend thousands of dollars to fix a non-problem.  If the EPA were to do the right thing and change its action level, all of this discussion about threats to people's well-being and impact on real estate values would cease. 
As a final thought, I once gave my presentation on radon to a group of folks at the University of Wyoming.  After the talk, an elderly rancher came to me to tell me that there was an abandoned mine a few miles from Laramie where folks would pay to spend time in the mine to cure their aches and pains.  Guess what was in the mine?  Radon.

Hans J. Mueh, BGen (Ret), USAF, PhD
Former Professor and Head, Department of Chemistry, USAF Academy      

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