The health effects of low level radiation are a continuing topic of conversation here and in many other places around the web. The Establishment view is known as the Linear No Threshold (LNT) assumption.
Using that model, which was first applied to radiation standards development in 1956, every dose is assumed to impart risk to human health, all the way down to the origin of zero dose before you get to zero risk. Since there is no place on the surface of the earth that has a background dose of zero, the model indicates that every human has a greater than zero probability of contracting cancer caused by radiation. It also implies that people who live in areas where the background dose from the local rocks or from cosmic radiation is higher than average have a higher than average probability of a radiation induced cancer.
In the opinion of many health and radiation professionals, that model does not make any physiological sense and it flies in the face of the results of numerous studies. However, the Establishment bodies that have been selected and approved by government bureaucrats continue to assert that their “meta” reviews of literature give results that are “consistent with” an assumption of a linear, no threshold dose response model.
Sometimes I feel like the debate is roughly analogous to trying to decide how many angels can fit on the head of a pin. Since angels cannot be measured, once can propose an infinitely high number and no one can prove that number to be wrong. For practical purposes, it really should not matter whether the model is linear or not since a low dose implies a low risk and there is no such thing as zero risk for a living being.
However, many people who refuse to accept much of what the Establishment says on any topic have — for some odd reason — decided that they would believe them this time. Of course, they see the assumption and raise it to the level of a mantra and chant “there is no safe dose of radiation.” They even use that mantra to try to force enormous expenditures to eliminate dispersed or diluted radioactive material that exposes humans to doses that are well within the normal variations in background exposure.
A recent story titled EPA Abandons Major Radiation Cleanup in Florida, Despite Cancer Concerns, originally produced by Global Security Newswire, has been picked up by a number of outlets and by quite a few members of the various groups with whom I correspond about nuclear energy and radiation matters.
It tells how people within the state of Florida — which was my home of record for my first 52 years — have pressured the EPA to abandon plans to attempt to clean up the soil in a 10 square mile area in Lakeland, which is about half way between Orlando and Tampa. The area is either near or on land that was mined to extract phosphate for fertilizer. In some areas, the background radiation exposure is slightly elevated because phosphate contains a modest amount of uranium and all of its daughter products, including radium.
That is no surprise to me; there was a time when the phosphate mines earned a little extra money on the side by processing their wastes to extract uranium. When the price of uranium fell through the floor during the 1980s, once we stopped building new nuclear power plants in the US, the phosphate miners closed down the processing lines and just left the uranium in the tailings.
The EPA bureaucrats wanted to force a clean up down to a level less than 1 mSv/yr (100 mrem/year) for the most exposed person; the state of Florida said that was a silly waste of money for anything lower than 5 mSv/yr (500 mrem/yr). Fortunately, logic and political clout prevailed and the higher standard was accepted.
I guess this is a long way of getting to the title point of this post. If you are hopelessly confused by the controversy and would like a good, readable source of information about radiation health effects, please download a copy of Radiation and Health by Thormod Henriksen and the Biophysics group at UiO (University in Oslo).
These health professionals have done the world a service by gathering credible information into an accessible format that can help people understand how radiation affects their bodies, what levels deserve concern, how they can protect themselves from those levels and when the levels are low enough that they can stop worrying and go on living their normal lives.
Please share the link widely and do whatever you can think of to thank the Thormod and his colleagues.
PS – I guess it might be worth explaining why I used the damning word “bureaucrat” to describe the EPA representatives who have established such low doses as the clean-up standard.
I lived on the west coast of Florida for about 10 years — between 1993-2003. Within ten miles of our house, there was a Superfund clean-up site that had once been the site of a phosphorous processing plant owned by a company called Stauffer Chemical. It was a beautiful piece of property right along the Anclote River. The clean-up had been in progress at least ten years when we moved to Tarpon Springs, but the government was not satisfied with the results. The site was declared to be a Superfund site in 1994; the cleanup was planned to last at least another ten years.
I attended the same church as the EPA representative in charge of the clean up. We chatted a few times after services; he eventually invited me for a tour of the site. During that tour I asked what was taking so long and what the risks were to the public. He told me that he liked Tarpon Springs and had no intention of allowing the site cleanup to be completed before he was ready to retire. He said there was no risk, but the standard was tight enough that it could never be met anyway.
Believe it or not, we never spoke again.
Apparently he must have earned his retirement, the Stauffer Chemical cleanup was declared complete in 2011.