Recently, the American Nuclear Society and the Health Physics Society hosted an historically important meeting on updating the scientific basis for low dose radiation protection standards. Attendees discussed the effects of low dose radiation, the existing radiation protection construct that has evolved to minimize the impact of those effects, and ways to take advantage of the vast level of knowledge accumulated over the past several decades to improve on the construct to obtain better outcomes in the future.
The meeting’s organizing committee deserves accolades for having recognized the importance of the topic, the need to break free from the common pattern of specialists meeting to discuss aspects of the topic within their chosen professional silos, the need to involve participants from many nations, and the need to hear from people who have had their lives altered by exposure to our current system of radiation protection.
The four years that the committee invested in arranging the meeting resulted in an exceptional event. One deeply experienced observer noted that it was likely the most important and potentially impactful meeting she had ever attended.
During the course of three tightly scheduled days that began around 7:00 am and did not finish until close to 6:00 pm, the nearly 200 meeting attendees heard from approximately 50 presenters and panel participants. Unlike many technical society meetings, there were no breakout sessions in which specialists gathered to hear each other.
Following most presentations and panels, there was a limited amount of time for questions and comments from the audience. All available minutes were enthusiastically used. Moderators worked diligently to keep the schedule on track, but were reasonably flexible in allowing important questions to be asked.
Unfortunately, time and other considerations occasionally resulted in the questions being left unanswered. This potentially frustrating result can be optimistically seen as a strong indication of the need for a continuing dialog that can more effectively approach satisfying answers and solutions.
Alan Waltar, the chairman of the organizing committee, told me that he had one major regret. For a variety of reasons, the final sessions were unable to achieve an agreed upon set of next steps. The committee has made a commitment to itself, however, to ensure that there will be follow through that prevents the meeting from being a one and done event that fails to make any substantive impact.
Presentations covered a wide range of perspectives and topics.
Some described results of epidemiological studies or wide reviews of a number of epidemiological studies that were consistent with the currently accepted radiation protection construct. Others provided results of animal, cell or tissue experiments that detected and quantified both immediate responses to carefully measured radiation doses and longer term responses to the immediate effects that appeared to show that the immediate effects were transitory and either repaired or eliminated as long as responses were not saturated.
Several of those experiments indicated that the radiation doses stimulated repair and recovery responses to such an extent that cellular damage done by agents other than radiation was also repaired, making the cell healthier after receiving a small to moderate dose of radiation than it was before exposure.
Other presentations focused on the effects of our current world-wide radiation paradigm that assumes all doses of radiation are risky enough to require avoidance involving extreme measures.
Several presenters and audience commenters described the costs that arise from efforts to keep radiation doses as low as reasonably achievable (ALARA) under a construct in which “reasonable” seems to be defined as anything that is technologically possible. They spoke about radioactive material clean up standards that protect critical groups of hypothetical people from doses that are small fractions of normal background exposure.
One of the most extreme examples discussed was the Washington state requirement to clean the Hanford reservation to a state in which the water found in monitoring wells meets the EPA drinking water standard of 0.04 mSv/year. Another was the EPA’s requirement to prove that a permanent repository for spend nuclear fuel is designed to ensure that no one during the first 10,000 years of repository operation will be exposed to more than 0.15 mSv/yr from material residing in the repository.
Other extreme measures of radiation avoidance include relocation involving abandonment of homes, personal property, businesses and real estate. They also result in avoidance of medically indicated diagnostic procedures. Attendees heard from a radiologist who told an emotional story of a young patient who needed a CT scan and from people who have spent a great deal of time working with displaced people in the Fukushima prefecture in Japan.
Note: Because the event organizers and attendees recognize the historical importance of the meeting, they are investing time and other resources to compile a complete record of the meeting. The full program as executed with the presenter names and affiliations can be downloaded. Most of the presentations are available now for download. The entire meeting was filmed. The resulting video files are being processed and will be made available for online viewing in the near future.
Three primary camps
The meeting attendees seemed to align into three major camps, each with perspectives shaped by their education and professional experience. Though there is some fluidity at the boundaries of each camp, the positions at the end of the meeting did not seem to have changed much from those at the beginning.
The first group includes those who accept the status quo in which the dominant directive associated with radiation is protection from all doses as much as possible. This group accepts the use of a no-threshold, linear dose response model and is not troubled by the fact that the model provides a foundation that makes it easy for activists to assert that “scientists” believe there is “no safe dose” of radiation exposure.
The second group believes that there is a large and growing body of experimental evidence supported by a sufficient number of human epidemiological studies to disprove the no threshold model. They believe that the absence of any evidence of harm below about 100 mGy during periods in which adequate time is allowed for healing is sufficiently strong evidence of a threshold at that level. They believe that situations that do not put anyone at risk of exceeding that threshold exposure are safe enough to be outside the need for regulatory control.
The third group is convinced that there is strong enough evidence that low doses of radiation stimulate repair and healing to assert that those doses are beneficial, not harmful. They believe that the assertion that all doses of radiation carry some risk not only results in unwarranted fear, but also unfairly prevents research into treatments that could improve human health and provide additional medically useful tools.
Though there were some areas of strong disagreement, and a number of people who openly advocated for a public rejection of the current established paradigm, it would be unfairly dismissive to describe anyone at the meeting as a scientific outlier. In fact, the meeting revealed that there is no existing consensus among knowledgable specialists in the field. It further provided strong evidence of a need for continuing the discussion and involving interested members of the public in the process.
It seemed that most members of all three camps agreed in several areas.
They believe there is a crying need for additional research that is well-conceived and targeted towards using modern tools to help overcome some of the gaps between experimental results and epidemiology. They particularly want to encourage research that helps to identify biological markers that can identify radiologically induced carcinogenesis. These do not exist today.
Most of the meeting attendees agreed that there is a dearth of interest among students and early career researchers in the fields of radiation biology, radiation epidemiology and other applicable fields. There are plenty of gaps in existing knowledge that indicate the need for continuing effort, but the current lack of funded research limits career opportunities enough to discourage entry into the associated specialities.
A majority of attendees agreed with the importance of actively discouraging use of collective doses that quantify negative health outcomes by multiplying tiny doses by very large populations. They agreed that radiation professionals should be willing to call out and publicly reject statements based on use of such calculations.
Aside: My personal position is that using cumulative doses – that is adding up small doses measured over extended periods of time – is equally unsupportable. It is especially harmful when people are told or allowed to believe there there is no healing associated with radiation exposure. Imagine how someone exposed as a child might feel about believing they are doomed to carry a ticking time bomb that might go off at any time. End aside.
Finally, even the defenders of the status quo agreed that the level of radiation fear among the general public and its political representatives is not supported by evidence of harm. Members of the groups that are confident there is a threshold or beneficial effects attempted to point out that the no-threshold assertion is a root cause of the fear.
Unsurprisingly, the defenders were loath to accept that interpretation of our current situation. One representative of the ICRP took particular care to point out that the Japanese government ordered the evacuations of the areas around Fukushima without any reference to projected exposure levels and also pointed out that reentry into evacuated areas wasn’t limited by the measured exposure levels.
What he unfortunately failed to understand or acknowledge is the fact that continuing to accept the “no threshold” assertion sends the message to decision makers that they must treat all radiation and radioactive material as harmful enough to be worth extreme avoidance actions.
During the meeting, a particularly well-placed and responsible defender of the status quo made the following statement when pressed to explain his defensive position in light of the research community’s collective inability to conclusively detect any effects below 100 mGy.
“Maybe it’s not possible. But I feel we must communicate this to the public. Say maybe there is something at low doses. Maybe there is nothing. We don’t know. We have to admit that. It’s a matter of honesty and transparency. But we can say for sure that it cannot be much. If it was large, we should see it. That is for sure.
The strong defenders of the status quo have been trained, by their own admission, to insist that it is impossible to declare any activity or level of radiation to be safe or even to say that it is acceptable. They insist that they must carefully and repetitively mention uncertainties and admit their lack of precise knowledge.
What they do not seem to understand or accept is that the “no threshold” model doesn’t project uncertainty. It falsely communicates certainty that there are harmful effects even if they cannot be detected. A phrase I heard too often during the meeting was “Absence of evidence is not evidence of absence.” That is the kind of argument that can be used to assert the existence of ghosts, spirits or angels.
Not being trained as a scientist, but as a leader and decision maker, I operate under different professional guidance. It is unethical for me to unnecessarily encourage fear when I know that effects of radiation below about 100 mGy are low enough to be obscured in the weeds of everyday living. If we have been looking for an effect for decades and been unable to find it, that’s sufficient evidence that it doesn’t exist.
It’s important to keep the conversation going. Substantive change is necessary. There are important areas of knowledge and expertise worth sharing among all of the camps described. I’m not an unbiased reporter and I hope that my commentary does not result in creating even more resistance to the necessary changes. I know some defenders of the status quo will never change their mind.
Not only do I understand the general difficulty of altering a long held professional position, but some of the defenders have specifically told me that they can never be convinced. That is regrettable. I hope that most will be able to more fairly evaluate the evidence and recognize that they have much to contribute to creating a better radiation dose response paradigm for both professionals and the public.
Final note: Last night, while thinking hard about what I wanted to say regarding discussions about low dose radiation and our current protection model, I learned that the plot of a new episode of FBI (a crime drama that has been placed in the slot that follows NCIS) revolved around an event at a nuclear power plant. That episode provides ample evidence that radiation and nuclear professionals have done a poor job helping the public understand our technical field.
According to the show the following untruths are real.
- Security drills involving real weapons (unloaded) are conducted in operating plant control rooms
- Events in spent fuel pools can contaminate an area with a 16 mile radius to a deadly level
- It’s possible to become dangerously contaminated by a small quantity of cooling pool water
- Nuclear plant workers have relatively open access to isolated quantities of Sr-90 and Cs-137
- Plant managers are so worried about their employment that they will commit murder to prevent an inspector from questioning their safety culture
- A company operating a 50 year old plant scheduled to close in a couple of years will stop investing in equipment needed for safety and the resident inspector will look the other way