I must admit that whenever the low-dose issue comes up, my first thoughts always go to Sayre’s Law. Named after Wallace Sayre, a Columbia University professor in the 1950s who once observed that “academic politics is the most vicious and bitter form of politics, because the stakes are so low,” the eponymous maxim states that in any dispute, the intensity of feeling is inversely proportional to the value of the stakes involved.
When it comes to radiation science, the shoe fits. Most of the significant issues are already well characterized. Yes, radiation causes death at high doses. Yes, it causes cancer and other health effects at medium levels, and it does so in a relatively linear statistical fashion.
But typically, at around 5 rem/50 mSv per year, the epidemiological “signal” of adverse health effects disappears into the noise of confounding factors like diet, fitness, overall good health, and the fact that more than one-third of us will get cancer at some point. Without the benefit of direct evidence in human populations, scientists can only theorize about the impacts of radiation exposure at these “near-background” levels.
There also seems to be considerable disagreement within the community over how to proceed scientifically. The epidemiological corner believes bigger studies are the answer, that the signal-to-noise ratio can be dialed up by increasing the size of study cohorts, most of which are nuclear workers with established occupational dosimetry histories.
Others think research should focus on the biological repair mechanisms like adaptive response, bystander effects, and genetic instability that could yield new information using today’s set of biomolecular research tools.
Then, of course, there are the advocates of hormesis, who believe that low doses of ionizing radiation have beneficial impacts on humans.
But this is where Sayre’s Law messes things up. In the big picture, the record is clear. Nuclear is the safest source of energy humankind has ever devised. But within the scientific microcosm of radiation research, the debate rages with little hope of achieving any form of consensus any time soon, and all the while the public remains confused and ill-informed, which creates unnecessary fear.
So, back to the executive order. Should we question LNT? Yes, every waking moment, as good scientists do. But should we abandon it before a more scientifically sound model appears? Probably not. Similarly, with ALARA, we’ve lost sight of its original intent, which is to optimize dose received instead of mindlessly minimizing it. Eliminating ALARA seems extreme, but emphasizing the “R” is way overdue.
Ultimately, to use a COVID analogy, there is no “curve” to flatten for radiation at or near background levels. Perhaps it is time to review our current regulations to see whether there are instances where we are requiring the equivalent of wearing masks in the car while driving alone.
Science doesn’t have all the answers, but we definitely need a better conversation.
