Spirited debate about BEIR VII and Linear No Threshold (LNT) Dose Assumption
A few days ago, I wrote What should “Radioactive Wolves” teach critical thinkers? and promptly got really busy at work. I put in several “half-days” (Navy lingo for a 12 hour work day) and did not have much time for paying attention to Atomic Insights.
When I finally got around to checking on things, there were already almost 200 comments. The early ones focused on a throwaway line or two in the post mentioning my suspicion that there might have been less accident than purposeful destruction at Chernobyl based on the incredible series of operational missteps. Most of the rest, however, turned out to be a running battle of words exchanged between a retired radiation protection professional and everyone else.
Bob Applebaum, the radiation protection professional, repeatedly defended the Linear, No-Threshold dose response assumption as representing the best available science. His primary source for that defense came from the BEIR (Biological Effects of Ionizing Radiation) VII report.
On the other side of the discussion, there were at least a dozen separate people who provided a number of different references, thought experiments, experience, and statistical analysis that called the LNT into question and described it as a useful regulatory assumption, not a model that accurately predicts dose response or that should be used to compute consequences of an accident like Chernobyl or Fukushima. One of the key sources that Applebaum dismissed is the March 2005 report titled Dose-effect relationships and estimation of the carcinogenic effects of low doses of ionizing radiation. Here is his rather enlightening dismissal of that report:
Bob Applebaum
October 28, 2011 | 9:34 PMNot my problem… that is a change the goalposts fallacy.
I live in the U.S.
I’m not going to respond to anything anyone has done in dozens of other countries.
Should the U.S. be a Muslim theocracy because some other country has decided to?
Am I compelled to respond to that.
Nope.
Applebaum also dismissed the Health Physics Society’s current position statement on low level radiation risk, saying that it was based on 1997 science and dismissing the commenters who pointed out that it has been updated and reaffirmed several times since it was first published.
Bob Applebaum
October 26, 2011 | 12:35 PMYou are in denial.
If you read NCRP, 1997 you can see the position paper reflects 1997 science.
BEIR VII reflects 2006 science.
Science marches on.
Reading through all of the comments may take some time, but if you are interested in the topic and want to learn more, your time would be well invested. I am going through the thread and may elevate some of the comments to become guest posts in their own right – with the permission of the original authors, of course.
Medical radio oncologists do not overly rely on LNT. It is however part of their toolbox.
Forgive me for repeating the comment I made on the radioactive-wolves post regarding LNT vs. Non-threshold. But I think an ultra low-dose lab would be worth establishing.
I highly recommend a report from a conference held in 2006 on ultra low-dose radiation and health. The lead experts were Dr. David Brenner, a proponent of the LNT hypothesis, Dr. Otto Raab, who supports the linear, non-threshold hypothesis, and Dr. Leo Gomez, who’s probably somewhere in the middle.
All three experts in radiation protection agree that below a certain threshold (10 rem) there is no scientific basis at present for assuming health risks. To study what actually happens to organisms receiving low-dose exposure, these scientists propose the establishment of an ultra-low dose lab half a mile underground in a salt bed that is low in natural background radiation. On the surface would be a control lab. I highly recommend that people on both sides of the issue read the report of a 2006 summit held to examine whether such an experimental lab would be a good idea. Almost all of the attendees agreed that it would.
http://www.orionint.com/projects/ullre.cfm
Not sure why such a low dose experiment requires a subterranean environment. Surely a well-shielded surface facility can be built to remove most external (cosmic/terrestrial) radiation. And the air could be filtered to remove radon and progeny. But what to do about C-14 and K-40 in the body from foods? Perhaps it would take a few generations of lab animals (mice/rats?) fed with food that contained minimal quantities of the major radioactive isotopes(produced via isotopic separation of potassium, or in the case of carbon, from fossil fuels). Several control populations could then be used to compare effects, exposed to combinations or variable quantities of natural or enhanced external radiation and/or radioisotopes in food, with all other non-rad parameters being equal.
I attended that summit on the establishment of the ultra-low-dose radiation lab. It turns out that there is chow for small mammals that has been cleansed of potassium-40 and other isotopes. The idea would be to have one lab on the surface with small mammals dining on normal chow and water. The control group. Meanwhile, half a mile underground in the same salt bed that houses the WIPP, there would be a lab that is shielded from a considerable amount of cosmic radiation and the salt itself has very little in the way of uranium, radium, or thorium. It’s probably cheaper than building an elaborate structure with many barriers to prevent radiation from penetrating. The idea would be to starve the experimental animals down below from radiation as much as possible. So they might also be enclosed in lead boxes or whatever. There is some indication that in a low-radiation environment bacteria do not thrive. What about with small mammals?
I agree that if such a laboratory shares the same access tunnel as WIPP and uses existing excavation devices, then the suggested underground laboratory approach would certainly makes economic sense. But I would argue that independently tunnelling half a mile down would not be cheap compared to shielded surface facility that reduces external exposures and food that reduces internal dose by a factor of about 100 (this is an arbitrary factor, I realize, but probably good enough to effectively be considered “zero dose”).
It’s too bad that the debate on that thread turned into an exercise in troll abatement. While I’m no fan of LNT, the discussion would have been better served by someone who could have advocated for it in a less doctrinaire fashion.
Hi Rod, I was wondering if you knew about this paper
http://junkscience.com/2011/09/20/shocker-nobel-prize-winner-lied-about-radiation-danger-data-suppression-abetted-rise-of-linear-no-threshold-model/
Cheers
Carlo
Carlo,
We have known about this story on this board as soon as it got out maybe 3 weeks ago.
It came out on Sept 20th …
Wade Allison author of Radiation and Reason, York UK 2009 writes: “The result is that new safety levels for human radiation exposures are suggested: 100 millisievert as a single dose; 100 millisievert in total dose in any month, 5,000 millisievert as a total whole-of-life exposure”.
In 2006 the United Nations Chernobyl Forum and in 2008 the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) showed in comparison to the Russian general population, a 15% to 30% lower mortality from solid tumors among the Russian Chernobyl emergency workers and a 5% lower average solid tumor incidence among the heavily radiated population of the Bryansk district. In the most exposed group of these people with an estimated average radiation dose of 40 mSv, a 17 % decrease in the incidence of solid tumors of all kinds was found. In the Bryansk district the leukemia incidence was not higher than in the Russian general population. According to UNSCEAR no increase in birth defects, congenital malformations, stillbirth or premature births could be linked to radiation exposures caused by the Chernobyl fallout.
More than 45 years ago, I introduced a lab exercise that demonstrated an ultraviolet radiation induced DNA repair process in bacteria. Over the years this interesting demonstration was successfully replicated by microbiology students many times. I regret that I did not have the foresight to postulate similar mechanisms for ionizing radiation in human cells.
Here are some basic facts about low and moderate radiation levels that provide us a basis for risk assessment of radiation health effects. Immunologists have found that additional radiation exposure induces several mechanisms in the immune system which function to improve our defenses against diseases. Additional radiation actually lowers our incidence of cancer. We now know that a process, “radiation hormesis”, mediates beneficial effects on health in humans. Radiation stimulation to the immune system’s damage-control is much greater than its direct damage to DNA molecules. The increase in the amount of DNA damage caused by moderate levels is relatively trivial—orders of magnitude less than the immune stimulation. Additional radiation turns on the synthesis of DNA repair enzymes and enzymes capable of destroying reactive molecules which have the capacity to cause mutations. Additional radiation also stimulates an arm of immune defense that rids the body of DNA damaged cells which could potentially turn malignant. The above perspective would suggest that our government regulatory agencies are setting radiation exposure limits nearly a 1000 time lower than necessary.
Hi Rod and others…if you look at the number of posts I made that day, I was pretty tired and didn’t have the energy to get into that second report.
What I found amazing was the religiosity…I still do. Virtually everybody referenced Cohen who I tore apart. Yet, the believers still believe. It’s like the Doomsday prophet who keeps missing his date…the believers ignore that and keep on believing.
Incredible!
Regarding the old HPS paper, it is based on 1997 science. Science drives the position of people…people don’t dictate science. If the HPS said the sky was purple, it wouldn’t make the sky purple. The paper is simply old.
But if you’re a believer…that won’t matter.
Apologizes for taking so much space. You did inspire me to setup my own blog (didn’t seem to really be an existing one on the Internet).
My first post is on Calabrese…http://ribjoint.blogspot.com/.
LNT deniers are welcome.
Remember…adaptive response is not hormesis.
P.S. Out of all the comments I posted I notice you only reprinted two negative (from your perspective) ones.
Posted like a true believer.
Have a good weekend!
@Bob – Your “tearing apart” of Cohen was not at all convincing. He earned a position of high stature and respect based on performing excellent research, using careful documentation, and providing good backup for his reported conclusions.
You have apparently not lived in the same world as I have for the past 51 years if you believe that everything that claims to be based in science is completely devoid of influence by the human beings that gather, choose and interpret the results. Some science is good and repeatable, some is biased by ideology or preconceived notions, and some is just downright sloppy. Some editors at journals do their job well, others have occasions when they are under pressure of deadlines or lack of sleep and do a poor job of selecting reviewers or even of proofreading the contributed work.
You said you did not have the energy to get into “that second report.” Are you talking about the French study that you dismissed out of hand because you live in the US? If so, please get some rest and feel free to come back and take a crack at explaining its supposed weaknesses to us.
I discuss the French study at my blog.
Discuss it here, if you have anything to say.
Posting it on pages where you have editorial control makes me wonder just how many critical comments will get through, particularly if they start to bite.
Your behavior on these pages doesn’t engender any trust on how you will behave on your own.
If you didn’t find my teardown of Cohen convincing.
YOU DON’T UNDERSTAND IT.
That’s really too bad.
Naturally.
What a flaming ego. Note that there is no allowance here for any inability on his part to communicate. If you don’t understand what he has written – the fault must be the reader’s.
Jesus wept.
Mr. Applebaum, it is quite possible to find your arguments understandable and yet still unconvincing.
To state anything else is logically inconsistent.
Your own blog, eh? That should make things much easier for you. Perhaps a statistical baseline can be established there for your commitment to objectivity and the scientific method.
Bob, if you believe in LNT, I have a few questions for you.
Do you personally worry about the chance of getting cancer from man-made sources of ionizing radiation? Why or why not?
Do make a conscience effort to avoid excess ionizing radiation such as avoiding eating potassium rich foods?
I want to know if you believe LNT is a useful tool for the average individual or as others have said it’s only useful as a regulatory guideline.
No, to all the above.
But that doesn’t mean the risk is zero…or even more ridiculously, positive.
LNT is useful as a model.
We see that the Universe is expanding, so in the absence of evidence to the contrary, we assume it has always been expanding. That’s our model.
Likewise, with high radiation doses we get cancer. As we go down in dose we keep getting cancers until we reach a point we can’t resolve any more.
It’s logically consistent (with the Big Bang theory and everyday life) to think cancers occur at a smaller scale…we just can’t statistically measure.
You need some strong evidence to show me that the Universe stopped expanding in the past.
Likewise, you need some strong evidence to show me that LNT is wrong and things progress in the OPPOSITE direction.
You haven’t given me that evidence.
I’m waiting.
I’m not going to debate hormesis with you.
But, as far as cancer goes, it has been said by many sources (of which I’m too lazy to dig out references for but they’re there) that everyone has some cancer cells in their body, even as much as being born with them from day one. Whether those cells grow to an uncontrolled state that doctors identify as cancer is another matter. So, how does one quantify that? When you are healthy, you could say that 99.99999% of my 60 trillion cells are cancer free, until one of them “decides” to get excited on me. So, if we already have cancer to some degree already, how can LNT possibly account and distinguish between naturally dormant cancer cells and those that were struck by a gamma rays and turned cancerous? I don’t believe it can.
I imagine an experiment could be done on mice with one control group living in a lead lined room and the other group that eats alfalfa tainted with cobalt 60 but those are mice, not people.
If LNT is just a model, then it’s not a very good one because it has been dredged up over and over again as a tool to thwart the progress of nuclear energy. In other words, regardless of its scientific merit, it has survived not because it’s beneficial, but because it’s a propaganda weapon.
First I don’t think anyone care what you think about this subject. I will remind you, and I will continue to remind you, that you are the one trying to convince us that LNT is valid.
Thus the onus is going to be on you to prove your hypothesis to OUR satisfaction, not the other way around.
The ploy of trying to reframe a debate such that we would have to prove you wrong, is an old one, but it’s not going to happen here. We don’t have to defend our position – you have to defend LNT. And your doing a poor job of it.
I for one, won’t fall for the provoking language that you use that suggests that you are holding an ascendant position in this discussion.
When you have to resort to dialectic tricks, dodges, and chicanery, in order to create an illusion that you are right, it’s rather plain that the underlying argument is very weak.
LNT deniers??? Well, that’s a new one, never seen the “denial” tag placed on LNT before. This could be the new “Nazi Rule of the Internet”. First person who resorts to calling the other a denier loses the argument by default.
Bob’s tenacity did at least provoke me into re-visiting BEIR VII to see how it justified LNT. I found it to be a deeply frustrating document. It does a poor job of explaining why LNT should be recognised as the best model for low doses.
It admirably explains how to construct a risk model; and it also explains that the reason it rejects other models is that there is insufficient evidence to support them at low doses. But it is conspicuously opaque when it comes to explaining why LNT should be supported when there is also a lack of evidence to support the LNT at low doses.
So I am still inclined to follow UNSCEAR’s line on this. UNSCEAR does not use any risk model, LNT or otherwise, for predicting mortality from low doses. This is due to the absence of compelling epidemiological evidence, and the high uncertainty in all risk models at low doses.
I did a search for the paper and found a summary document. I find it curious that of the man-made sources of ionizing radiation, nuclear testing fallout and the nuclear fuel cycle were thought to be 2% and 1% of that portion respectively. Yet, no mention of fossil fuel radiation was included unless that would be lumped into “consumer products” which was estimated to be 16% of the man-made total. 6000 tons of uranium are pumped into the atmosphere by coal burning just in the USA alone. Certainly that should be taken note of, no? I don’t know how much radon gas is released by fossil gas extraction but it must be a lot.
In sum, I think it’s safe to say the radioactive emission profile is far, far higher than that of the nuclear fuel cycle, even with accidents included. Yet despite this, fossil fuel is given a free ride and virtually ignored as a major source of low level radiation.
@Jason – You have brought up one of the reasons why I believe that stubborn insistence on the importance of the LNT assumption for radiation doses attributable to nuclear energy related development (but not for fossil fuel extraction, not for airline employees, not for other forms of mining, and not for medical exposures) is closely associated with efforts to limit the beneficial use of nuclear energy for human society development.
We have gone around and around on Atomic Insights about the reasons why there are some people who are so adamant about halting nuclear energy development that they join others in organized, combined efforts to make it stop (or at least slow way down and get way more expensive than it naturally is).
I have taken the position that the majority of those who are so inclined do it for greedy reasons. However, I concede that there are at least three reasons for people to be against nuclear energy.
1. They are ideologically opposed to human society development
2. They are ideologically opposed to any “unnatural” source of reliable energy, both fossil fuel and nuclear
3. They are economically opposed to developing nuclear energy because they recognize that it poses a competitive threat to whatever kind of energy supply system they prefer to sell into the market.
In any case, every one of those groups grasps at the notion that there is something so fundamentally wrong with nuclear energy that it must prove beyond a shadow of a doubt that it poses zero risk to every individual before they will stop their organized effort to slow it down as much as they can.
Bob has repeated that he is not opposed to nuclear energy and that he actually favors a nuclear renaissance. However, he feels strongly about ensuring the world does not decide to accept that the danger of low dose radiation are so small that they disappear into the “noise” of all other dangers that humans face while living here on Earth. He feels so strongly that he authored perhaps 50 or more comments, some quite lengthy, on an Atomic Insights post and then decided to start his own blog with that subject as the very first one posted.
The more I learned about Bob by reading his comments and then searching the web (useful search is “RACE applebaum memphis incinerator”), the more I realize that he is not a troll and not just a guy who gets his kicks from arguing with others. Bob is a bright guy. He is bright enough to have been the chairman of a committee of the American Academy of Health Physicists. He is bright enough to have started his own business and achieved far more success with that business than I or almost any of my numerous associates ever did. (His RACE company was at one time (2005) a $40 million per year (2005) revenue company that employed 120-200 people.)
He and his partner(s) sold that company in 2006 to Studsvik for a total of $36 million.
http://investors.studsvik.com/files/press/studsvik/1045261en1.pdf
He even, at one time, defended his company’s operations – which were to collect, process and package radioactive materials – and the tiny risk that it posed to neighbors in language that most on this list would feel comfortable in using.
http://mstbdlt.blogspot.com/2005/08/race-card.html
And
http://www.memphisdailynews.com/editorial/ArticleEmail.aspx?id=28267
I am now struggling to understand just which of the three categories I listed he falls into or if I have somehow missed one.
Actually, I know I have missed one. I have neglected to mention the insiders in the nuclear energy enterprise who may not even believe that they are opposed to its development, but who believe with all of their fiber that it is a fundamentally hazardous business that requires absolutely zero tolerance and extraordinary efforts (and expense) to ensure absolute safety and perfection.
Chairman Jaczko falls into that category. Near the end of his career, Admiral Rickover fell into that category. Many of Bob’s colleagues in the radiation protection community fall into that category. Many of the folks in the industry’s QA organizations fall into that category.
Rod – I think the category you are missing is not one of those opposed to nuclear power, but those that wish to take advantage of it in a very shortsighted fashion.
In my opinion, two parasitic cultures have grown around nuclear technology, both artifacts of Cold War paranoia: first is the radiation protection industry and professionals working in the field that depend on the continued acceptance of the the linear-non-threshold dose-response model, despite the fact that this model has been thoroughly discredited on multiple occasions; the second the nonproliferation bureaucracy. The latter having no more of an evidentiary foundation than the former, but is similar in that a host of people depend on its assumptions for their jobs.
These people depend on maintaining the status quo of fear and worry to keep their jobs. I don’t really believe that they “believe with all of their fiber that it is a fundamentally hazardous business that requires absolutely zero tolerance and extraordinary efforts (and expense) to ensure absolute safety and perfection.” at all, or if they do, it is by self-delusion.
@DV82XL
Points well taken. I knew I was missing at least one significant source of motivation for making nuclear energy development as difficult as it is.
Bob, coud you address the use of DDREF in BEIR VII? It invalidates the idea that BEIR VII uses LNT at all, since DDREF-based calculations are no longer linear with higher dose effects. Also this factor can be used when encountering threshold-like results to deny or ignore the existence of a threshold simply by an arbitrary manipulation of DDREF.
Please elaborate why the DDREF is arbitrary?
Is NASA’s estimate to Andromeda arbitrary? Did they just pick some arbitrary number?
Why go to NASA for an estimate of the distance to Andromeda? Why not the IAU?
Let’s just stick to DDREF. How do you justify low dose LNT when DDREF means that the effect isn’t linear?
Rod –
Did you ever notice you bear a striking resemblence to Ben Stein?
http://ribjoint.blogspot.com/
Many of the professionals I interviewed while writing a book about nuclear power mentioned the fact that there is a huge industry devoted to providing barriers between the public and nuclear materials, like spent fuel. We’re talking $billions to “protect” the public from, say, an exposure in excess of 15 mrem/year. Why not 20 mrem, or 10 mrem? This number was chosen arbitrarily. And there are some big corporations that are happy to come in with their crews and heavy equipment to keep us same from those hypothetical mrem. They are happy to take a long time to accomplish their mission. In other words, “feed at the govt. trough” as one scientist observed. The LNT is a money-maker. If the ultra-low-dose experimental lab is ever established and finds that there is a threshold below which no health impacts can be detected, $trillions could be saved. But of course the “barrier industries” would fight that big-time.
The worst is that these are folks that nominally on our side of the hill. It’s unfortunate that they have taken such a shortsighted view of the potentials, because even with more relaxed standards, a full Nuclear Renaissance would mean more than enough jobs for all of them.
This really is Luddism in its purest form, and like the weavers at the dawn of the Industrial Revolution they are failing to see the potential for increased employment in a changed economic environment.
Some people just don’t get the big picture. 36% percent better paying jobs in nuclear than average salary where a nuclear plant exists…
‘The Nuclear Energy Institute (NEI) estimates that private investment in new nuclear power plants has created 14,000 to 15,000 clean energy jobs over the last few years in the US alone. Operation of a nuclear power plant not only generates 400 to 700 permanent jobs, but they are jobs that pay as much as 36 percent more than average salaries in the area they are located.’
Why not have a speed limit set at 50 mph or 70 mph or 25 mph?
Just because you can’t figure it out, doesn’t mean others haven’t.
You claim the nuclear bombs dropped on the Japanese cities of Hiroshima and Nagasaki in August 1945 provide us with the data we need to verify LNT.
Well it seems about 66 per cent of the original inhabitants of the two cities survived to 1950, since then their individual health records have been extensively studied.
By 2000, 7.9 per cent of them had died of cancer, compared with 7.5 per cent expected from rates found in similar Japanese cities over the same period. This shows that the extra risk caused by radiation is very small compared with the background cancer risk, and less than the 0.6 per cent chance of a North American citizen dying in a road traffic accident in 50 years.
Not surprisingly, those who received higher doses developed more cancers. But those subjected to doses less than 0.1 sievert showed no significant increase in solid cancers or leukemia. Nor did they suffer an increase in the incidence of deformities, heart disease or pregnancy abnormalities. So there is a practical threshold of 0.1 sievert for any measurable effect due to a single acute dose.
Ref:<(Radiation Research, vol 162, p 377)
So it would seem your contention that the Nuclear Attack Survivors Studies are somewhat less definitive than you’ve been making out.
Actually, there was an article in WNA stating that ICRP is lookng now at all increased radiation (airlines, medical, etc). Maybe this is a good thing as all exposures will have the same yardstick.
I am wondering, the HPS still has their position paper on non-inclusion of doses below 5 rem immediate or 10 rem/yr in population dose calculations. Does this still represent their consensus? My recollection is that they accept LNT, but have the caution on population dose due to the uncertainties of adding up such small doses.
I just checked HPS and I am a little off: it is 5 rem per year or 10 rem lifetime. The position paper was updated July 2010, so I can conclude it represents the consensus of the US HP community.
That would be a dumb conclusion.
Don’t bother asking why – the Great Applebaum has spoken -your conclusion is dumb – no explanation is necessarily.
Decorum prevents me from expressing myself in detail.
That is the HPS position. However, the ICRP, the NCRP, the US National Academy of Sciences, UNSCEAR have all indicated that LNT is consistent with current scientific evidence.
That being said, ICRP doesn’t think calculating health effects from “trivial” doses is appropriate.
The real problem is, the effect of low doses is uncertain.
Europe is evidently planning to act upon the ICRP guidance by proposing legislation to protect workers from natural radiation as well as man-made.
http://www.world-nuclear-news.org/RS-EU_proposes_radiation_protection_directive-1710115.html
Me thinks Bob Applebaum is a bit of a showboat.
Admire his skill in business & debate. But one thing is prancing around on stage in a ‘New Future Nuclear’ theater like a James Cagney singing “Yankee Doodle Dandy”. Quite another to advance science and the nuclear industry for fun and profit.
My take is the industry has suffered due to a lack of vision in for example, SMR technology in contrast to its nuclear critics I would rather witness a burgeoning nuclear business like a Space Nuclear business where human habitat and propulsion is observed around our solar system made possible with Nuclear Thermal Rocketry (NTR) and extra terrestrial nuclear powerplant electrical production with advanced SMR technology. Or revising the Test Ban Treaty and the Outer Space Treaty to reflex uses in nuclear space propulsion and deflection of (NEOs) Near Earth Object that threaten to collide with Earth or even underground runway oil/gas drills accidents mitigating enviro- pollution. But again the United States nuclear educational community seems tamped down by fruitless debate pitting anti-science deception with advancement. Rather than promote a Ed Calabarse toxicology ‘adaptive dose advancement’ on cellular response we’re still stuck with businesses that take out nuke trash rather than recycle nukes.
I know I’m another blogger on a rant.
But like the hamburger commercial of days past saw a lady in a commercial lift her bun to see a small postage size serving of beef saying “…where’s the Beef?”
A better question would be. Where has the nuclear R&D and use been for the past 35 years?
The genie is out of the bottle. The US had its chances. Now France, Russia, India and/or China are going to lead the Nuclear Renaissance with SMR.
US better wake up.
Could this be the first time a proponent of LNT has felt the need to go public in the manner of Bob Applebaum? Why would that be? They’re used to enjoying regulatory supremacy. Is there a perception within the radiation protection industry that a real threat has emerged?
We can only hope.
@Craig Schumacher
It’s a crying shame half a generation of bright students were turned sour toward a career in the nuclear industry because of false perceptions in media by LNT proponents.
I hope you’re view is correct.
Yes, the same way that flat-earthers threaten geology.
Then the question becomes if you don’t feel threatened by those that have legitimate questions about the efficacy of low-dose radiation, why go off the deep end with the name calling and insults?
It certainly looks like your trying to defend a weak position by the way you are arguing, and you have been avoiding questions.
If it looks like a duck and quacks like a duck… I have yet to see a mainstream geologist spend so much time and exude so much vitriol as you have done on these pages dealing with flat-earthers – mostly they just ignore them.
This thread reminded me of an article I read years ago:
http://www.wired.com/science/discoveries/magazine/16-07/pb_theory
Of course, even if petabytes allow us to form a real correlation on millirem (and I am not yet convinced), my guess is that we would find an insignificant relationship at such low dose levels. Still, the satisfaction of “staking the radiation vampire” has an emotional appeal. 🙂
Bob Applebaum seems to be saying that if you don’t believe in hormesis then you must be a believer in LNT hypothesis. I would like Bob to explain in physical terms why a linear with threshold model is impossible in his mind.
It seems to me that just about everything in toxicological terms can be diluted to the point effectively creating no increased danger. Why is radiation different?
I want don’t you to cite studies (appeal to authority) I would want a clear physical explanation as to why damage from radiation can’t fall below a effective damage threshold like milk proteins which cause damage to the DNA.
Because a single photon can ionize a single atom.
Is that simple enough?
If not, how simple does it need to be?
@Bob – do you deny the biological reality of immune systems and other repair mechanisms? Claiming that a single ionization has any chance of causing a cancer many years later seems to ignore the way that complex organisms behave.
That’s the key in my opinion. We aren’t dealing with petri dishes containing cultures of single cell types. We’re dealing with organisms that are complex systems, wholes that are more than the sum of their parts, organisms that evolved in a far more radioactive environment than exists today.
Complex multicellular organisms have immune systems that prevent and suppress cancer, and generally work incredibly well.
The human organism is a highly resilient system and should logically shrug off low levels of radiation damage, especially since radiation damage is very unprivileged damage (e.g. it doesn’t attack privileged channels in the organism like binding to receptors or attacking metabolic systems or the like – it just ionizes pre-existing compounds).
LNT would be a (more) reasonable assumption for unicellular life which does not have the sophisticated self-repair systems that complex multicellular organisms have.
To claim that one photon will cause cancer by ionizing one atom is an appeal to probability.
This is a justification based on probability, which is a logical fallacy when an unwarranted assumption that something will happen, because it can happen. This is precisely what you are implying with your statement.
Life has had billions of years to evolve defences against free radicals, reactive oxygen compounds and other physical and chemical assaults that can damage cell components, including our genetic material, DNA. Those same, powerful defense mechanisms protect us from low levels of ionizing radiation – from the cosmic rays that strike the earth surface to the radioactive particles continually released from the earth’s crust into the air around us.
Explain why the ionization of a single atom leads us to the conclusion that the damage from a single ionized atom is beyond the limits of the body’s defenses and ability to heal?
Your answer is irrelevant to the question. The question is regarding a dynamic whole i.e. a disease response. You cannot aggregate from damage to single part to the whole of the system. It’s called the fallacy of composition.
Explain why there cannot be a threshold for a disease response in the whole system. Give me a physical explanation of for system wide failure based on a extremely low doses.
I haven’t made up my mind of this issue of LNT vs. LWT or hormesis. But you are going to have to do better than logical fallacies.
My understanding is that LNT is a risk response model i.e. we know the risk high levels of radiation exposure and therefore absent knowledge of a counter mechanism the risk must follow a linear path downward with exposure levels. Is this correct?
Bob, if it is simple as that, the probability of cancer should be proportional to the number of cells in the body.
Why do elephants live longer and have less cancer than mice?
Why do whales have less cancer than elephants?
A single free radical can damage DNA. Yet exercise, which produces a monstrous quantity of free radicals, reduces cancer risk.
Why?
What is lacking here seems to be the consideration of a NET positive health effect that comes from substances or processes that have deleterious effects at high doses. As someone said later on, excercise produces free radicals, but these are more than offset in terms of adverse health effects compared to the benefits of exercise. Of course, the initial pain from starting an exercise program (especially if it is not ramped up gradually to allow muscles to recover), or starting one when one is in poor health, could possibly kill you, but a sedentary lifestyle will entail greater risks down the line… Another example is all the people who survive bacterial or viral infections when exposed to below-threshold concentrations (these viruses are present EVERYWHERE, even in “sterile” environments, but only present a hazard if they overwhelm the bodies defenses – which, again, are not equally endowed on all individuals).
Also, adaptiver response might be a consideration. Say you grow up in an ultra-low-dose environment (previous comment). Is it plausible that exposing lab animals who have been raised in well below normal levels of radiation to a sudden increase to what we otherwise would consider “natural” levels may in fact kill them at a higher rate before their bodies have had a chance to develop defense mechanisms. You know, like kids living in standard sanitary conditions (even eating some dirt), vs kids living in a overprotective sterile environment getting hit hard when they enter the “real world”. Or the case of unvaccinated vs vaccinated kids. Again, here we see the “net benefit” coming into play in this case from a societal protection (one could say “collective dose” to coin the rad analogy), where the individual has a finite risk of being killed by the vaccine, but the group of vaccinated individuals is highly protected.
“It seems to me that just about everything in toxicological terms can be diluted to the point effectively creating no increased danger.”
Do you have a source? How do you define “effective”?
@Bruce Behrhorst
“I would rather witness a burgeoning nuclear
business like a Space Nuclear business where human
habitat and propulsion is observed around our solar
system made possible with Nuclear Thermal Rocketry
(NTR) and extra terrestrial nuclear powerplant
electrical production with advanced SMR technology.
or revising the Test Ban Treaty and the Outer Space
Treaty to reflex uses in nuclear space propulsion”
As I may’ve mentioned here as well other blogs, my cousin, Jean Esquerre, was one of a handful of black engineers working on the lunar module at Grumman back the sixties, and their tech applications divison was itching at the progress of (and possible contract for) the nuclear drive research in Nevada, which was super sucessful (they literally fired-up a naked reactor in the open air to test it — no mutants reported running around the area then or since) but I remember hearing how spitting disappointed he was at how early anti-nuclear sentiments in Washington and the U.N. helped push the project “off the cliff in back the stove” as he put it. Had it been developed we could’ve been making five month manned round-trips to Mars in the _1980s!_. How much fear and ignorance has retarded progress! — as we’re witnessing now with nuclear plants.
James Greenidge
@James Greenidge
…totally agree w/ you.
I think the State of Nevada has a tour of PROJECT NERVA site. A tribute to the men and women who built and tested light weight small fast reactors for space and industry. Much good science advances came from this work science still in use today. Like so many bloggers here hope to see a brighter future for graduates in nuclear engineering and the nuclear sciences. To have a good career in a proactive industry in a growth economy toward prosperity.
Americans need to continue its rich nuclear legacy.
NUKE THE ENERGY !
Good morning –
A radiation linear dose response (with cancer as the observed effect) has historically been a macro-phenomenon, not a micro–phenomenon. In other words, to determine the response, we look at cancers which have manifested themselves. Not cancer at the cellular level.
I have tried to elaborate on my blog under “KISS For LNT Deniers”:
http://ribjoint.blogspot.com/
(The next post down has some funny videos, if you want a good laugh)
Radiation interactions with cells are micro-phenomena. A typical ionization absorbs about 34 ev of energy. A single photon might pass through you and not interact at all. Or a single photon (let’s say 0.5 Mev might deposit all of its energy in you…do the math and divide 0.5 million ev by 34 ev). Or a single photon may only deposit a fraction of its total energy in you.
But each photon you are exposed to INCREASES YOUR RISK of getting cancer.
Just like each mile you drive INCREASES YOUR RISK of getting in an accident. Yes, I’m aware of brakes, turn signals, and seatbelts.
How do you know that risk is significant and doesn’t reduce to noise at some level?
A single free radical damages DNA. So why shouldn’t we apply a LNT model to radical damage?
I read your post and once again you are assuming that not believing in LNT means you must believe hormesis. I pointed out before that is a fallacy.
Why should we conclude anything about the risk when as your post says “LNT…is not based on biological concepts of our current
knowledge, it should not be used without precaution for assessing by extrapolation the risks”
If we don’t see a response below a certain level of exposure why can’t we just conclude that we don’t know and therefore can make no risk assessment about something we don’t know about.
From your blog:
“As more and more uranium was mined to support a growing nuclear power industry, we observed an excess cancer rate in the miners. These folks were exposed to a high concentration of radon (it doesn’t matter what the numerical value was).”
How do you know this? How do you know that increase rate of cancer was from the uranium mining. How did you exclude other factors such as smoking? And how do you that high concentration weren’t leading to high levels of radiation of exposure above a possible threshold?
I’m just asking basic questions. I’m waiting for answers but scientist aren’t very interested answers from what I’ve seen. Scientist like Bob seem more interest in projecting mathematical models rather explaining physical causes.
I constantly hear scientists on the internet complaining about how people don’t know or believe in what scientific says in increasing numbers. Perhaps if the scientific community (especially on the internet) weren’t acting like interminable A-holes people might actually be more receptive instead of treating people question as if we children that need to “KISS.”
There have been some commenters here who promoted hormesis. The best dose response curve that fits the data is the LNT.
I never said anything about “significant” risk. The risk is small at small doses.
There is a science called epidemiology. Epidemiologists do studies all the time, not just on radiation effects. They routinely look for correlation between an observed effect and a possible cause, ruling out confounders. I could give you a link describing in detail how they do it. But I’m guessing it would be over your head.
If you go back to first comments on the subject, from days ago…I wasn’t the A-hole. I was trying to point out politely that most of the people had their fact wrong. And perhaps “troll” was the nicest compliment I received.
“The best dose response curve that fits the data is the LNT.”
That may be true for a single massive dose of radiation or vitamins given 65 years ago, but it proves nothing about the effects of continuous low dose exposure to radiation or vitamins.
BEIR VII has pages of references to radiation studies. List the studies that measure the effects of low dose continuous exposure over years or decades (fourth request).
The BEIR VII conclusions are not applicable to chronic low dose exposure resulting from nuclear accidents or any other source.
Bob, you have not provided a shred of experimental evidence to support your claim that LNT applies to chronic low dose exposure.
Very late answer but we know the increased cancer risk was from the uranium mining because the effect was seen mostly on Indian and Mormon miners, who both usually have a very low rate of lung cancers. And in the case of Mormon’s it’s unambiguously because Mormon’s faith strictly forbids smoking.
“But each photon you are exposed to INCREASES YOUR RISK of getting cancer.”
Nakedly asserting that which is to be proved.
A comment or two from a non-health guy.
Bob never answered the point that cancer rates or *any* other health effects show up statistically anywhere for those that live in higher back ground raditation areas. Why? I wanna know.
Secondly, the rejection of the LNT thesis doesn’t automatically mean one supports hormesis.
I think it’s interesting that many of those that do support the LNT do so only a modified way, that is the ‘non-threshold’, while ‘existing’ means nothing, practically. A list of LNT advocates were quoted in this manner by Gwynth Cravens on the other thread. I find this “interesting”.
Flowing from that, hormesis-deniers, seem to generally, want to increase the FUD factor in the public discourse. Not Bob here, and this blog is “Not About Bob” but about the LNT. It seems the LNT is serving a *political* purpose. When Siemens goes before health committees and *lobbies* for more strigent and lower radiation protection levels, one has to really wonder. It makes me wonder. It makes people I raise this wonder.
What is clear too, is that associating the denial of LNT with those that are in denial about climate change is silly, and quite underhanded. They are completely different and, the methods used in discussing both the LNT and Climate Change are quite different. It doesn’t help this discussion to make such charges. In fact I don’t even like the use of “Climate Change Denial” as a nomenclature for discussion as it associates, unfairly, people who challenge the climate change consensus with Holocuast deniers. My opinion only and I oppose the challengers of climate change.
Bob should understand that the reason so many in the pro-nuclear community challenge the LNT is because they see how it’s been used by yahoos like Caldicott, Wasserman, Nader, etc. Unfortunately, but true.
David
I realize the rejection of LNT doesn’t imply hormesis. However, many commenters were promoting hormesis. Hormesis has no evidence to support it.
Epidemiology is based on statistics. They give their results at the 95% confidence level. When you refer to high background areas that means you’re talking about something like a large area in which there is a high AVERAGE level, and you are assuming that people are exposed to that average level.
It’s hard to make a 95% confident association with that approach. Good epidemiologists only take that approach as a last resort. The better approach is to look at INDIVIDUAL levels. When we do this, like in the radon studies, we excess cancers at low doses, whether the individuals are in high or low average levels or not.
We have calculated risk factors per unit dose. That’s the point…no one should assign any greater or lower risk other than what has been calculated for the purposes of propaganda. If someone has a valid reason, that could be different.
That’s why I first commented…we’ve done the hard work of calculating the risk. And to the extent a Caldicott or someone else exaggerates it…slam ’em.
But it’s kinda hard to slam ’em, when some people here were playing the hormesis game.
Keep with the science…it is very robust, and difficult for someone (Caldicott or Calabrese) to conquer.
I don’t see your points on “deniers”. If someone doesn’t believe something which is supported by the evidence, and you’ve tried to make them understand, and they still deny…..”denier” seems appropriate to me.
“When you refer to high background areas that means you’re talking about something like a large area in which there is a high AVERAGE level, and you are assuming that people are exposed to that average level.”
What? Unlike the case of the populations in the cities of Hiroshima and Nagasaki which where there were not estimates of doses, and assumptions were not made about exposures?
“It’s hard to make a 95% confident association with that approach. Good epidemiologists only take that approach as a last resort. The better approach is to look at INDIVIDUAL levels. When we do this, like in the radon studies, we excess cancers at low doses, whether the individuals are in high or low average levels or not.”
Apparently not. To re-post what I wrote above:
The results of the Hiroshima and Nagasaki studies showed those who received higher doses developed more cancers. But those subjected to doses less than 0.1 sievert showed no significant increase in solid cancers or leukemia. Nor did they suffer an increase in the incidence of deformities, heart disease or pregnancy abnormalities. So there is a practical threshold of 0.1 sievert for any measurable effect due to a single acute dose.
Ref:(Radiation Research, vol 162, p 377)
This is on top of the fact that your contention that observations made on large populations exposed to a high average dose are unreliable is errant nonsense.
The bottom line is that a calculated risk, based on very selective data sets, is never going to be more reliable than observation. Observation does not support LNT, but supports a threshold model.
You have failed to demonstrate why those real-world observations should be rejected in any consistent manner, rather you have tossed out smoke-screens of BS in the hope that no one will notice.
The Japanese assumptions are based on individuals, not averages.
There is a 0.1 threshold for a study involving a fixed number of people over a fixed period of time. There was once a 0.2 threshold, now it’s 0.1. This study is measuring many kinds of cancers, not just one. Some cancers haven’t manifested yet.
With radon, the studies could be done much quicker. Less uncertainty, one cancer, as many people as one needs are available.
Same with iodine, one cancer, plenty of people in the case of Chernobyl.
Chernobyl leukemia results show excess cancers.
I’m not surprised logic and facts are nonsensical to you.
“the Japanese assumptions are based on individuals, not averages:
More attempts to hide the flimsiness of your argument. The statement doesn’t even make sense within the context of the discussion.
At any rate there are several studies that have been done following radiation workers where there is both good, accurate, long baseline dosimetry, AND detailed individual health records that fails to support the linear model.
Beyond that you are now implying that the very study that you have held up as the gold standard for proving LNT is in error. Let’s go over it again:
those subjected to doses less than 0.1 sievert showed no significant increase in solid cancers or leukemia.
Radiation fearmongers have been raising the specter of latency every time their predictions fail to align with observations. When the cancers from Chernobyl weren’t as high as their said they would be, they said wait ten years. Then it was wait twenty years. Your now claiming the nuclear bomb cancers haven’t all shown up even though its now more than sixty years.
Looks to me like grasping at straws.
“But each photon you are exposed to INCREASES YOUR RISK of getting cancer”
Can I ask a question, Dr. Applebaum; do you advocate all employed in the Empire State and Chrysler and Woolworth and other non-glass tower buildings here in NYC to move their jobs and also not go the Museum of Natural History and Grant’s Tomb so they don’t get daily zapped into a mass of tumors from all the baddie particles irradiating from their granite and stone brickwork?
There’s a point when trying to find what the lowest rad dosage biological effect is becomes, as a matter of practicality and raw dirty reality, meaningless.
James Greenidge
DV82XL
Thank you for suggesting Pierce. Some interesting things out of his epistemology that are pertinent to the debate.
His first rule of logic, the sole rule of reason is that, to learn, one needs to desire to learn and desire it without resting satisfied with that which one is inclined to think. He then presents a corollary:
“Do not block the way of inquiry.”
Then he goes on to list four common barriers to inquiry:
(1) Assertion of absolute certainty
(2) Maintaining that something is absolutely unknowable
(3) Maintaining that something is absolutely inexplicable because absolutely basic or ultimate
(4) Holding that perfect exactitude is possible.
I however disagree with his assessment on action. He absolves action of its importance. I think that ones life is the culmination of past action of their own. It is the choices that we make and demonstrate in our lives that are the only judge of our character. Our motivations guide our actions.
I offer this to the debate about LNT. If there is somebody out there who can offer an argument that does not block inquiry in their methods, please say so. Bob’s actions over the past week are sufficient proof of his desire to block critical thinking and the development of understanding that render him incapable form being able to adequately represent the side of LNT.
Peirce held that a hypothesis should economize explanation for plausibility in terms of the feasible and natural. Based on Peirce’s Abductive reasoning which allows the precondition a to be abduced from the consequence b, we can posit:
When life began on Earth almost 4 billion years ago, background radiation levels were five times higher than those we experience today. Life adjusted to this, as it did to all other forms of energy to which it was exposed – heat, light, electromagnetic.
However one thing life did not apparently do was to evolve an organ that can detect ionizing radiation whereas it did for other kinds of radiant energy, and avoidance behaviors to limit overexposure. This lack of an ionizing radiation sense points to the fact that living organisms have no need to avoid such a low risk phenomenon.
If one cleans up a radioactive spill, takes a Geiger counter and sees that the counter can’t discern any radioactivity above background….
That doesn’t mean there is zero radioactivity, it only means the counter doesn’t have the sensitivity to detect the radioactivity, based on the existing background levels and the low residual contamination levels.
Since we understand basic principles, like a surface has porosity, contaminants have particle sizes, there can be chemical affinities, etc. we logically conclude there is still undetectable contamination there.
The burden of proof is on someone who claims there is zero radioactivity there.
Just because a study doesn’t have the statistical sensitivity to discern below a certain value, doesn’t mean there is zero occurrence of effect. The burden of proof is on the person who claims there is zero effect.
Since no one has evidence of zero effect, let alone hormesis, most of us stick with logic.
It probably does look like grasping at straws.
Wait… so Logic tells you that if you have a known reading of radiation levels before an event, and that after the clean up the readings are the same as they were before the event, this is Logically proof positive that there is still contamination.
So by that logic, if I spill my beer, then dry the carpet with a towel, then observe that the moisture level in said carpet is the same or lower than when I spilled my beer, logically I must assume that carpet is now forever wet?
From my understanding of Radiation detection, we are not talking about an imprecise measurement such as running your hand over the carpet. This is something where a Bus Sized event can kill us, but we can detect down to a Pin Head sized event, and count how many angels are dancing away on it.
So for me.. logic says that if I clean an area back to the radiation level it was before an event… IT’S CLEAN. There is no Hidden Radiation huddled under an Null Field waiting for helpless pregnant woman to walk by and create a 12 headed demon baby.
Well, Bob’s analogies have never been all that good.
For example, take this line:
Of course there’s not “zero radioactivity”; that’s just Bob’s strawman. The ever-present background radiation is still there. For all practical purposes, however, there is no excess radioactivity. And at that point, you can call it a day.
Note that Bob is shuffling the shells. Keep an eye on where the pea is.
For example, he dismisses the HPS position statement because it is “based on 1997 science” (even though the HPS reaffirmed it last year). However, all the position statement says is that “below 5-10 rem (which includes occupational and environmental exposures), risks of health effects are either too small to be observed or are nonexistent.” Nowhere does the statement assert that the risk is known to be absolutely zero.
Ah yes the sensitivity of the equipment issue.
We were totally clueless about the world around us until instrumentation was designed to monitor the world around us. (Incorrect assumption by the way since observable interactions with the world is how instrumentation was developed in the first place.)
However, we didn’t know any better about the “dangers” of the world around us when we could only measure in parts per million but we were told to be aware.
Then we didn’t know any better about those same “dangers” when the instruments could measure in parts per billion but we were told to be concerned.
But now that equipment can measure in parts per trillion we must now all be afraid of the very air we breathe and the water we drink as well as the food we eat.
Not saying that better instrumentation isn’t a good thing. Higher orders of sensitivity has helped us understand the world around us and has helped protect us in numerous ways. But an understanding of the base concepts must be applied when looking at the issue of outputs and sensitivity of models developed to run on computers where inputs can be controlled versus outputs and sensitivities of complex systems that function in a world of multi-dimensional inputs. Highly sensitive instrumentation and computer models can acutally lead to false conclusions. Engineers can not and must not assume computer models and any instrumentation used for data gathering are automatically correct.
And I am not talking about climate models so don’t bring up that false analogy again. I come from the world of FEA where dynamic computer models of complex structures have been known to output strange results that have little bearing in the real world.
And once again you are trying to shift the debate. No one is saying that there is NO radioactivity in the scenario you proposed as a thought experiment. In fact I have had to deal with stainless steel components that acted like sponges, was known to be still “contaminated” in the pores, cost thousands of dollars to clean EVEN THOUGH the risk to the personnel and public was approaching zero if not zero had I been allowed to perform a proper risk assessment. However, none of those details are the issue since, of course, there is background radiation.
What many of us are saying is that at the levels discussed in numerous posts on this question, the LNT model does not fit the outcome as we can witness in the real world. Otherwise literally millions of Navy Nukes, DOE workers, research scientists, medical personnel and many other job titles too numerous to list that work with or around radioactive material should already be experiencing much higher numbers of cancers and those cancers would be directly attributable to their exposure to radioactive material then the “control group” (i.e. the rest of the known world not involved with handling or directly working around radioactive material). Since that isn’t happening, many of us question the validity of LNT as a predictive tool.
Yes there are clusters but those are directly attributable to known events such as the Chernobyl issues. But those are not what you have been arguing. You have been arguing that all of us who have worked in and around radioactive material will come down with cancer due to our exposure. That isn’t happening in the real world.
And by stating the following:
Just because a study doesn’t have the statistical sensitivity to discern below a certain value, doesn’t mean there is zero occurrence of effect.
you are invalidating some of your own arguments over the past week that this debate has been playing out.
One cannot make the claim in logic, the law or science, that something exists, and then demand that be accepted as existing until proven otherwise.
I really don’t know how you can even begin to think you can get away with that sort of nonsense here at this stage.
Well, Descartes tried to link the existence of God thru logic. But that is another topic.
And failed miserably.
From a logic standpoint, for something to demonstrate consistent reasoning it must meet the criteria that given the same set of information, that one can derive the same proof or disproof of a hypothesis. This does have a mathematical representation which I will forgo unless if somebody is really interested.
The consistency requirement is the foundation and reason for the peer review process that developed over time.
This is the first “macroscopic” check of the validity of a hypothesis. How is it then that the French academies, arrived at similar conclusions of the UNSCEAR, while our own NAS arrived at a different conclusion? Logic states that when applying the same methodology the outcome can only be changed by restricting the set of data.
UNSCEAR and NAS match well enough (LNT).
The French concluded hormesis (anti-LNT)…they just don’t provide any evidence as to why.
No, they didn’t. Hormesis is not mentioned even once in their executive summary.
On the other hand, the report certainly questions the LNT assumption, and it “confirms the inappropriateness of the collective dose concept to evaluate population irradiation risks.”
Their short report contain 306 references to journal articles and reports.
Gee, Bob, you should try actually reading the documents that you want to criticize. There’s more to this field that just what is written in the BIBLE … er … BEIR report.
I did read the report and commented on it in my blog:
“Regarding comparing the two reports…it would take me months to do a side-by-side detailed analysis. I can only point out some obvious larger scale differences.
The purpose of the BEIR VII report was to determine which model (of the 3 above) was the best model that fits the data for LET radiation only.
I don’t know what the purpose of the French report was (what triggered it). It seems to consider both LET & HET.
I have no idea how the authors were chosen for the French report nor what their backgrounds are. It looks like there was 9 from 3 organizations. But the 9 could actually be part-timers in the organizations and be more independent. A good study would say.
In the BEIR VII report there 17 authors. They are all independent and from diverse backgrounds. I can’t write all the details here, but the selection process is very formal.
There is no sign of secondary review with the French paper. The BEIR VII, after completion, is sent to over a dozen independent, diverse reviewers.
The French paper lacks many details..it’s 58 pages compared to about 400 pages in BEIR. The number of reference studies looks to be about a third, but I didn’t count.
The most obvious technical difference is that BEIR VII actually performed a detailed risk analysis (with full details). The French paper only discusses other papers. It is intellectually lazy.
The BEIR risk analysis shows that there is an excess risk at 0.1 Gy of 2,100 cancers.
The French paper states, on Page 22, “However, for low doses (below 200 mSv) and a fortiori below 20 mSv generally encountered within the context of radioprotection, epidemiology can neither confirm nor refute the existence of an increased incidence of cancer”.
Since the French paper lacks the detail of BEIR, it doesn’t provide the quality of evidence to accept either hormesis or threshold.
For example, the French paper, on Page 11, says:
“At low doses and low dose rates of ionizing radiation, the pro-apoptotic effect dominates
and the damaged cells, of which there are only a few, can be eliminated or controlled.”
But BEIR VII doesn’t see it that simply…they have evidence of Locally Multiply Damaged Sites, which are independent of dose rate.
For most of the technical issues described in the French report, you find a more detailed discussion in BEIR. So, it’s hard to know if the French considered things to the level of BEIR or not.
All in all…BEIR is the gold standard. The French report around tin.
October 29, 2011 6:09 PM ”
The study doesn’t provide enough evidence relative to BEIR as to why it didn’t accept LNT. I am presuming that they give greater weight to hormesis-like effects mentioned above.
Sorry, Bob, but I have no interest in reading your blog. I have read enough of your dogma here.
I’m just wondering, however, why you are so sloppy (intellectually lazy?) as to misrepresent their conclusions and their evidence in your comments here?
By the way, 0.1 Gy is the very upper end of the definition of low dose used by the BEIR VII report. Thus, it is not surprising that it would agree with a LNT extrapolation from high-dose data. This is where the high-dose model and the low-dose model are supposed to meet. Such a risk analysis says nothing about what happens at doses of, say, 10 mSv.
It might be useful to look at page 145 of BEIR VII, especially Fig. 6-1. In the big picture, to be debating what goes on <0.1 Sv is pretty ridiculous.
"For both the mortality and the incidence data, risks of solid cancer increased with dose up to about 3 Sv, with little evidence of nonlinearity in the dose-response for doses in the 0–3 Sv range."
This is unpardonably irrelevant. Doses over 0.5Sv cannot be described as low-level doses. Data that includes effects above this will be dominated by the strong response, high-leverage end of effects.
What happens below 0.1Sv is what is driving all the agony of relocation and the expense of (pointless) clean-up in Japan. It is very much worth debating.
@ Brian:
Yes, it does..it provides a trajectory. You can’t look at this graph and just state something happens other than LNT w/o evidence:
http://www.nap.edu/openbook.php?record_id=11340&page=145#p2000e6f39960145001
You can’t say we don’t have a clue what happens to a dropped ball after it falls linearly 50 feet and has 5 inches left to go.
Aside from your sniping…LNT-deniers keep moving the goal posts. If BEIR could resolve at 10 mSv, you’d criticize it for not resolving 1 mSv.
G.W. and evolution deniers call science which doesn’t fit their predetermined agenda, dogma too.
You must be kidding me!
I guess Georgia Tech doesn’t teach you folks how to read a graph. Note:
(1) The “smoothed estimate derived from the points” is clearly non-linear
(2) The points have no errors associated with them
(3) The errors that are provided for the smoothed estimate are 1 SE. If you want to consider a 95% confidence interval (the weak epidemiological standard), then you have to multiply those errors by roughly two. After that, it is apparent that the uncertainties in the smoothed estimate easily include zero excess relative risk at doses below about 0.1 Sv, although it is difficult to tell exactly from the poor quality of the graph.
(4) It’s quite possible that the errors presented in this crude graph are underestimated, particularly at low doses. Notice how the points at (roughly) 0.20 and 0.25 Sv are over twice the distance from the smoothed estimate than the standard error presented in the graph.
Bob, you’re not talking to children here. Some of us have research degrees and know how to analyze data. Save the kiddie talk for you blog.
That’s a load of BS and you know it. Estimates of risk for exposures of around 10 mSv have very practical consequences, which is why I picked this particular figure.
@Bob – if the ball that is falling is big enough and light enough and the field on which it is falling is covered with rather dense grass that is a few feet tall, it is quite likely that the ball will never actually touch the ground.
The point that many of us continue to state – in many different ways – is that we live on a planet where the “grass” or “noise” of background radiation makes it highly unlikely that something below the grass is worth worrying about. There are way too many real dangers in life – like avoiding the biological nasties that often kill people who do not have energy purified water or energy supplied refrigeration – to unduly worry people about the possibly “non zero” but certainly trivial risk of radiation doses below about 100 mSv per year.
Rod – It’s worse than that. As I mention above, Bob’s analogies are terrible. Here he is using an analogy of a deterministic phenomenon to argue for an effect that is inherently stochastic.
(Aside: Furthermore, he’s bad at math. A ball doesn’t fall “linearly,” it follows the curve of a parabola, as anyone who learned anything in Physics 101 knows.)
We’re not talking about whether a ball hits the ground, we’re talking about health effects. A more appropriate analogy would be the risk of injury or death from falling. Here is an analogy that I put together several months ago:
Let’s say that I observe that roughly 50% of people who fall 4.5 meters survive the fall, and let’s say that I also note that almost nobody survives a fall of over 9 meters. I can draw a line through that and conclude that if 10,000 people fall 0.005 meters, I will get 5 projected falling deaths. Do these projected deaths make any sense? Of course not! Nobody would expect five people to die from falling half a centimeter.
I crafted this analogy to explain why it is ridiculous to assume (based on LNT) that air travel is killing roughly 11 passengers each day from exposure to radiation, which is what the LNT assumption and the idea of collective dose tell us.
Bob said:
“You can’t say we don’t have a clue what happens to a dropped ball after it falls linearly 50 feet and has 5 inches left to go.”
There are a very large number of possible curves that said ball can follow in its last five inches of decent.
Namely the height of the grass on the lawn, presents of rocks, or a mit all present obstacles to the path of the ball that were not present above its 10ft decent height, and thus would alter the linear curve as it approached zero.
However, intelligent experience people can make predictions about what could happen in the last 5 inches and be close to what happens in reality. They can also be quite wrong.
Lets just say for argument sake that there is a glove on the ground that the ball falls into. The curve is that of a linear with a threshold of 1in.
Please explain what data present and collected over the 49ft 7in flight path that can be used to determine the presence or absence of the glove.
I guess I should read all of the comments before posting.
Bob, your graph is for the survivors of the atomic bombs dropped on Hiroshima and Nagasaki.
This is not at all relevant to us who want to find the risk from nuclear power – a constant low type of exposure as opposed to nuclear bombs that are sudden flashes of radiation. Indeed, such flashes of radiation are designed to kill people, by dosing them with an amount of ionizing radiation that far exceeds any capacity of the human body to repair itself. This has no relevance to the hormesis model, which is about continuous exposure to radiation or toxins, as it looks at body repair mechanisms and stimulating mechanisms.
It is akin to the analogue below of taking 52 aspirins during one year versus taking 52 aspirins in one hour. Same dose, radically different health effect.
Here’s a study that looks at such constant exposure, in very high doses in fact, and finds only reduced cancer risk not increased:
http://www.ecolo.org/documents/documents_in_english/low-dose-Cobalt-taiw-06.pdf
Particularly strenghtening the cause of the hormesis model is the fact that cancer risk is not just lower, it drops over time – with increasing gamma ray exposure.
Hi Bob Applebaum
You showed very early that you have a low regard for scientific method. Your ability to be a trouble maker has shown to be useful in bringing some intelligent and useful comments from those who disagree with your claims and points of view.
If nothing else you have helped me indirectly to see the value of understanding Hormesis.
I am just wondering how you feel about the future generations being born into a world with dirty fossil energy that could easily be replaced by clean nuclear energy.
Radiation samples need to come from bombs that existed long ago. I think you need to revise how you are contributing to society.
The Japan Times is carrying an article on the effects of low levels of radiation. For a newspaper article, it is good.
http://www.japantimes.co.jp/text/nn20111103x2.html
The first time I was convinced of hormesis (radiological or else) is when my doctor explained to me that shocks to my bones when exercising don’t make them weaker but stronger ! If you’re not convinced, look at this muay thai guy’s kick : http://www.youtube.com/watch?v=maQINqPI7S0
Bob Applebaum’s hand waving with arguments from authority hasn’t changed my “belief”, all the reverse.
BEIR’s and Applebaum’s disregard of biological repair and defense mechanisms is most evident in the omission of the dose rate.
Dose rate isn’t just important, its everything. If I take one aspirin each week for a year I’ve taken 52 aspirins. The health effects are trivial, quite possibly beneficial; acetylsalicylic acid is a known beneficial substance in low doses. But that same 52 aspirin dose, taken over one hour, is extremely dangerous to ones health.
The dose is exactly the same, the health effects couldn’t be more different.
The LNT supporters don’t try to explain this, in fact they base themselves on information from high dose rate (=pulsed) nuclear bombs and medical procedures, to try to explain what is going on at lower dose rates. They are deliberately starting out with the worst dataset, trying to explain the risk of taking one aspirin a week based on a single deadly dose. The best attempt the LNT supporters make at modelling this is to apply an arbitrary multiplication factor for higher dose rates. But this is arbitrary and still just as silly: if 10 people all take one aspirin a week for a year it still doesn’t produce the health risk of one person taking 52 aspirins in one hour.
There is a simple explanation for all of this. The human body is a chemical processing and waste treatment plant. It can take a certain rate of toxins and waste in per hour. If the amount of waste and toxins going in, exceed the capacity of the plant, the toxins and waste accumulate to possibly dangerous levels in the plant. There are no linear effects here because of the plant’s capacity to treat waste, as long as that capacity is not exceeded all is well. In fact if the plant is not running it will get rusty and won’t work when needed.
There is no point in trying to fit linear no threshold models to this. It is inherently a threshold system.
The hormesis theory at least tries to explain what is going on rather whereas the LNT deliberately applies a theory known to be fallacious “just cause”.
Cyril,
I don’t think anyone is disputing that radiation exposure has threshold effects. In that sense, acute exposure to aspirin is comparable to the hematopoietic, gastrointestinal and neurovascular health effects of acute radiation exposure.
However, there are clear differences between these types of biological responses and long-term health effects (e.g. radiation-induced cancer). For instance, in acute radiation syndromes, the health effect, the speed at which the condition advances, the prognosis, the degree of pain, and every other feature of the health effect are functions of the radiation dose to which the person is exposed. In radiation-induced cancer, none of these things are functions of the radiation dose. Also, radiation-induced cancer is probablistic, not deterministic. Another difference is cancer is a latent effect.
Therefore, long-term health effects are not necessarily “inherently a threshold system”, and the current state of knowledge (as most, if not all, relevant scientific organizations agree) is the health effects of low-dose radiation are uncertain.
No the health effects of low-dose radiation are NOT uncertain. The whole point of this debate is that there is an official line that states that there is a linear effect down to zero, for exposure to ionizing radiation and observations that show that below a threshold it has no effect. This is a political, not a scientific issue.
Much practical science is practiced within a degree of uncertainty, it is inherent in the very structure of the subject, however there are many examples both of engineering and policy-making that that have proven effective with a much lower degree of certainty than seems to be required in this case. In other words, disproving LNT is being held to a far greater standard than that of many other medical theories, and this stinks of politics.
Hi DV82XL, I think recognize your username from other places than here. Do you use it often?
The NRC understands the health effects of low-dose radiation is uncertain. They regulate in a manner that they believe ensures the health and safety of the public, which means LNT. However, for non-regulatory actions, they also consider other dose response models.
“In other words, disproving LNT is being held to a far greater standard than that of many other medical theories, and this stinks of politics.”
Given that all scientific organizations that I am aware of (except for the French Academy of Medicine) have indicated that current scientific evidence is at least consistent with the LNT hypothesis, I guess I disagree.
…and perhaps the HPS. Their support a truncated dose, so perhaps they also may not agree that all current evidence is consistent with LNT.
Yes ajnosek, I use DV82XL all the time.
Well the fact that the French disagree in itself is an indication that there is more to this than simple science. However if one looks at the justifications used by those regulators that embrace LNT, one finds that there is more than just the Precautionary Principle being invoked.
Rejection of all contrary evidence on what appears to be very flimsy reasoning is usually the hallmark of a political rather than scientific agenda, and this is typical of reports such as BEIR VII. This may comfort policy makers but it is not seen in policies like those made for vaccinations for example, or other toxic pollutants.
Radiation is a hot-button item we know, and public attitudes can and does influence policy in matters like this. This I believe is what is happening here.
The problem is that even if one excuses this on the grounds of simply being overly conservative, the net effect is to raise the possibility that there is a real risk, when none in fact exists.
I assume I do not need to find the credentials of the scientists that make up these panels to you. In my experience, the main reason that people have opposed such scientific working groups is because their findings are “inconvenient” for the policy they want. And it isn’t just the pro-hormesis types. Here is NIRS also bashing BEIR VII: http://www.nirs.org/mononline/beirvii.htm
These types of systematic, largely unjustified rejection of scientific working groups isn’t just low-dose radiation. You can see it other inconvenient “hot-button” issues too, like those that deny the IPCC reports. Although low-dose radiation is different because it is still largely uncertain.
“Radiation is a hot-button item we know, and public attitudes can and does influence policy in matters like this. This I believe is what is happening here.”
You may think that public attitudes can and will change policy for more conservatism, but in my experience, the pro-hormesis types are also quite an active and noisy bunch. I need to keep reminding my friends that the health effects of low-doses are still uncertain.
I read through both articles. Some interesting conclusions from both. The first identified a baseline form the Taiwanese society of the roughly 7172 exposed to be 169 natural cancer deaths, with the IRCP model predicting 219 based on the LNT model. The second report identified 141 total cancer deaths, and supported their conclusions with a LNT model and threw out Chen’s report based on not accurately counting the eligible candidates.
If the societal average cancer rate is higher than an exposed population by 16% that is not insignificant. Yet the second paper, Hwang et al states that their results confirm LNT
By the way the DDREF used in BEIR (DDREF=2) is based on the Japanese bomb survivors, it is not based on our accumulated experience of occupational and accidental exposure.
I assume that the distribution of the density of age of the people matched that of the general Taiwanese population, sharing the same general cancer incidence rate. In an accident scenario the effected population will likely have a similar age profile. Thus an average chronic exposure of 47.8 mSv/yr will yield a 16% reduction in total cancers to the general population. The NRC as I recall uses 100 mrem at the site boundary as the first threshold and then 100 mrem at 10 miles. If they were to expand this to 5 rem then the citizens surrounding the plant would be better off (cancer wise) with a reactor accident on the scale of Fukushima.
In large case studies like this, the lifestyle variables that are not under the control of the experimenter do not have an effect on the outcome if they do not effect the reproducibility. The population of 7172 is very likely a solid representation of Taiwan in age, demographic, and lifestyle. This will predispose them to the general population cancer rate. Both reports failed to mention any significant deviation from this reasonable assumption.
The evidence suggests a different issue is at hand. Hwang et al uses a linear regression ( of three regressors) for each of his two random variables on a Poisson distribution. He does not incorporate prior information into his model and looks at “just the data” but not the context of the data. A more rigorous approach would put a prior on beta0, the “baseline” regressor, to that of the cancer rate of the normal unexposed population. If one wanted to use a linear model for the regression then the results would likely have a very bad R^2 value and would indicate a negative number or a very small positive number. The marginal distribution for the beta2 and beta3 regressors would be right around zero within 2 sigma, meaning inconclusive results. This is where a quadratic would work nicely to give more accurate results and explain how the cancer rate was lower than the general population. One can also build a latent variable into the model to look for the threshold, not at all that difficult. Or one could fit it to a hormesis model… But I suspect that would be too radical.
I agree life time monitoring is definitely in order for this population. We will likely see the cancer rates inch up toward the average incidence of cancer in the general population.
After looking at both of these studies, why we are so conservative? What is it that we are being precautionary against, success?
@ajnosek,
The use of an anti-nuclear group that thrashes BEIR is equivalent to saying a stuck clock is right twice a day.
Ajnosek,
People *are* disputing that radiation exposure has threshold effects, why do you think it is called ‘linear NO THRESHOLD model’?
What goes with chemical toxicity also goes with cancer. There is not a clear difference at all!!!
As a matter of fact, there is not a shred of evidence that small doses increase long term cancer risk. We don’t see this in Chernobyl, we don’t see it in Nagasaki and Hiroshima, we don’t see it in the Taiwanese appartments that were contaminated with cobalt-60, we don’t see it with nuclear shipyard workers, etc etc despite the decades long lead time here. We don’t see it anywere. Nor do we see any long term genetic damage rising up. What we often, but not always, see, is the opposite: less cancer, not more, in irradiated groups.
These ideas of cancer being caused by a single ionizing particle or a single asbestos fibre, are simply notions that sound logical, but have no grounding in empirical studies. Yet radiation risk wonks do use them, and their artifacts such as the notion of a “collective dose” which tries to cumulate trivial effects to get to a high death rate that is not observed anywhere.
The notion of a “collective dose” is so absurd, it can only be made clear using an example.
Over 50,000 tonnes of aspirin are sold each year. That is 50,000,000 kg.
We know that the LD50 of aspirin is 1750 mg/kg body weight.
Let us assume a typical aspirin taker has an average weight of 80 kg. This means that 140 grams of aspirin will cause 50% of the aspirin takers to die.
So dividing 50,000,000kg by 0.14kg and then taking 50% gives 192 million deaths from aspirin each year.
This is absurd. Yet it is exactly what the linear no threshold is saying. It simply omits the dose rate, as well as the individual dose, the most important variables of all. The idea that a model that omits the two most important variables should be widely used in risk assessment is so blatantly moronic, I can’t get my head around it.
All models are wrong. Some models are useful. Other models are so wrong they are not useful at all, they are making the analysis worse.
“People *are* disputing that radiation exposure has threshold effects, why do you think it is called ‘linear NO THRESHOLD model’?”-cyril
I don’t want to speak too much for Bob, but I believe that he probably agrees hematopoietic, gastrointestinal and neurovascular health effects of acute radiation exposure have dose thresholds.
“We don’t see this in Chernobyl, we don’t see it in Nagasaki and Hiroshima, we don’t see it in the Taiwanese appartments that were contaminated with cobalt-60, we don’t see it with nuclear shipyard workers, etc etc despite the decades long lead time here. We don’t see it anywere. Nor do we see any long term genetic damage rising up.”
We can’t measure it. Which itself is significant, but ‘how significant’ is for the epidemiologists to decide.
“So dividing 50,000,000kg by 0.14kg and then taking 50% gives 192 million deaths from aspirin each year.”
You are almost certainly mixing acute health effects with long-term health effects. In the high dose region, deterministic health effects are not linear, yet cancer is. Do you disagree with this, too?
You are relying on this argument, which says:
‘All negative dose responses to stimuli that we can measure are functionally the same, and therefore those that we can’t measure must also be the same.’
This is already incorrect because we know all the ones we can measure aren’t all the same. But even if they were, this does not necessarily mean the ones we haven’t measured will also be.
“The idea that a model that omits the two most important variables should be widely used in risk assessment is so blatantly moronic, I can’t get my head around it.”
As you already know, BEIR doesn’t omit them. It just doesn’t incorporate them they way you like.
@ Ajnosek. If we can’t measure the risk, then why do we use things such as collective dose?
Actually Ajnosek, we can measure it, eg in the Taiwanese radioactive appartment study there is a clear positive health effect, and it increases over time (dose), just like the hormetic model predicts. The dose was very high and there is certainly no linear increase in cancer as you suggest. The opposite in fact. So to answer your question, yes I disagree that, in the high dose region, cancers are linearly increasing. The very opposite has been seen in the Taiwanese study, and also in various studies of nuclear shipyard workers.
The fundamental difference – what is missing here – that I tried to point out, between the Taiwanese appartments and the Japanese atomic bomb survivors, is not in dose, but in dose rate.
The Taiwanese appartments got a lower cancer risk because of the low dose rate. It has nothing to do with the actual total dose – in some cases over 4 Sieverts. It has to do with the many years over which this dose is spread; this is all hormetic mechanism.
To be clear, I was talking about the notion of collective dose, which many people use to show how dangerous nuclear power is.
The typical assumption is that 10 sV is deadly so each 0.1 sV of ‘collective dose’ gives rise to a 1% excess cancer mortality.
The whole notion of collective dose is that you can infer a death rate without knowing the individual dose and/or dose rate. Even for studies that know with high precision what the dose is, you must still know the dose rate for each individual. We know that the dose rate for Japanese bomb survivors is extremely high – it all happened in a flash. This is again similar to eating a lot of aspirin at once. Even if you survive there are likely permanent or long term health effects from severe aspirin overdose.
This notion of collective dose without knowing individual dose rates is simply wrong on biological and factual grounds, as well as several epidemiological studies.
I read a lot of such studies and always try to learn more. Over time I’ve come to realize that the dose rate is far more important than the total dose itself. Since LNT doesn’t treat this in any scientific way – indeed they deliberately confuse them and keep them entangled with other variables – I cannot support such models.
@ajnosek
You said, “As you already know, BEIR doesn’t omit them. It just doesn’t incorporate them they way you like.”
That is a true statement. My question to you is through what a priori information are the weightings for the different data sets analyzed. Without a priori knowledge of the assessment of the impact of chronic exposure, the least biased estimator is to assign equal weight to all data. On the original post an epidemiologist weighed in and brought up the issue of hormesis being identified in other biological mechanisms and supported for radiation exposure. Which would suggest a reverse weighting for chronic exposure data in determining chronic limits. And conversely, weighting acute dose more for acute exposures.
From a regulatory stand point, how do you regulate? Federal regulations only have one exposure metric for dose rate and that is for 3 rem/qtr. Under this one could get 3 rem in September and turn around and get the remaining 2 rem in October. My point with that is the regulations are set up for acute dose. There is no specified time line for the exposure.
The model for the LNT ignores the importance of chronic vs acute. It lumps them together. Although BEIR does acknowledge this to some extent it is not explicitly modeled. How we construct imperfect models is based off of using all of the information that we have at hand. Not just parts of it.
Acute models are good exposure controls for radiation workers and accident responders. Chronic models are good for determining the siting restrictions.
As it sounds like you work for the NRC, how about a challenge? Propose modifying the regulations for nuclear reactor siting based on chronic exposure data. Maintain the regulations for acute exposure for protecting radiation workers. Does the evidence suggest this methodology? If it does then do we have an obligation to regulate off of the best evidence at hand? Does the evidence contradict this? If so how?
What would be the impact on the implementation of reducing the restrictions of siting reactors close to population centers? Low cost district heating comes to mind as does waste water treatment and water purification. Being from Wisconsin, having heat for very little frees up a good deal of capital for other ventures. Heat is so important that it is a state tax deduction.
What is the risk to Madison to replace the Charter Street heat plant with an mPower module? What is the benefit? What is lost and what is gained?
(Side note: if you think getting the union bills based through the state legislature was drama just wait to drop this bomb on the campus greens… They would probably resort to burning themselves to prevent the operation of the reactor. I am not kidding.)
I said high dose region, but I guess I really should have said high dose/dose-rate (i.e. acute) region. Radiation-induced cancer from acute radiation is linear. Other types of health effects from acute radiation are not.
From what I understand, the taiwanese cobalt-60 study was flawed. They did not account for age, and young people naturally don’t get as much cancer. A reanalysis was done to account for this and concluded:
The results suggest that prolonged low dose-rate radiation exposure appeared to increase risks of developing certain cancers in specific subgroups of this population in Taiwan.
http://informahealthcare.com/doi/abs/10.1080/09553000601085980
“Since LNT doesn’t treat this in any scientific way – indeed they deliberately confuse them and keep them entangled with other variables – I cannot support such models.”-Cyril
It is treated. It is called the Dose and Dose-Rate Effectiveness Factor (DDREF). (…Or are you challenging it as not being “scientific”?)
“From a regulatory stand point, how do you regulate?…” –Cal
The NRC regulates radiation exposure from both stochastic and deterministic standpoint, but I’m doing this from memory. The TEDE limit is 5 rem/year which is meant to protect against cancer, but the specific organ doses are usually much higher because they are protecting against deterministic effects. An annual dose rate limit is still a dose rate limit, but I understand your point that the instantaneous rate could still be very high. Even so though, it cannot be a very long high-dose rate.
“The model for the LNT ignores the importance of chronic vs acute. It lumps them together. Although BEIR does acknowledge this to some extent it is not explicitly modeled.”–Cal
I model LNT (as well as other dose models), and I explicitly model the DDREF.
“Propose modifying the regulations for nuclear reactor siting based on chronic exposure data. Maintain the regulations for acute exposure for protecting radiation workers. Does the evidence suggest this methodology? If it does then do we have an obligation to regulate off of the best evidence at hand? Does the evidence contradict this? If so how?”–Cal
I don’t quite understand. The NRC’s main concern is severe accidents. The risk of severe accidents should be considered on everything from the reactor design to how the plant is operated, because those risks are real (or in the case of low doses, those risks may be real, heh).
The NRC doesn’t regulate according to best estimates, they regulate with conservative safety margins in order to ensure public safety.
“What would be the impact on the implementation of reducing the restrictions of siting reactors close to population centers?”–Cal
I could be wrong, but I don’t think there are regulations specifically targeted at proximity of nuclear reactors near population centers. A utility will need to show that they adequately protect the public whether they are near a large city or out in BFE.
I’m from Wisconsin too, and I went to school in Madison. Most of the liberal art majors are blissfully unaware that there is a reactor on campus. Probably for the better, heh! Are you studying nuclear engineering?
@ajnosek
I graduated from there in 1999, got to meet El Wakil and had Bill Voglsang for my radiation class, he retired shortly thereafter.
My questions were more rhetorical than those that required specific answers. I was attempting to elicit questions about the current methodology that we use to administer our regulations. The thought process in those questions is that if the underlying fundamentals do not accurately identify the risks then why are we still regulating to these standards?
I had issue with the reactor response plans in the Navy, which are based somewhat on what the NRC expects from utilities. I never liked the risk assessment methodology that they were based on. The training and cultural mentality within the organization as to the “hazards” of radiation precluded many more rapid and assertive methods of casualty control. I also had my men spend an inordinate amount of time tracking every single last mrem. I could have easily converted 2 of my 4 ELT’s into regular mechanics had NR adequately addressed the risk of radiation.
We believe culturally that LNT is the “best” representation of what the risks are of radiation. In my time in the Navy, I saw first hand the consequences of not accurately identifying risks on both sides of the street. Cocksure and you get run over and almost loose the boat. Chicken____ and you get no good deliverables to the NCA and theater commanders and people die because you didn’t deliver. Life is hard, we cannot ignore information for the sake of conservatism. That is the principle of the precautionary principle that is fallacious. Be honest in your knowledge and hold nothing back, your life and the lives of others depend on that honesty.
I only know El Wakil from his Power Plant Engineering book. I don’t know Bill Voglsang.
I can see why conservatism doesn’t work in the navy. Ensuring safety can be anything but. On the industry side however, we aren’t at war. That isn’t to say we don’t have occasional competing priorities. Cooling the reactor too fast can lead to pressurized thermal shock, which is why operators initially closed the isolation condenser in Unit-1 at Fukushima-I, for instance.
The thought process in those questions is that if the underlying fundamentals do not accurately identify the risks then why are we still regulating to these standards?
I don’t think we do. Our use of risk-informed decision making for instance, will help us remove overly burdensome regulations while strengthening weak ones. Also, the NRC Fukushima Task Force has identified a number of areas for improvement as part of lessons learned from that recent event.
Funny thing about “Power Plant Technology” That book and El Wakil’s generalist approach to understand everything within the context of everything is what got me going down this path. I owe him a great debt for his books.
We are at war. In more ways than I care to admit. Energy is our economy it is what makes our economy go and it is what drives our standard of living. We cut back on energy those items go. An adequate supply of inexpensive primary energy is what holds our government together. Without it, our country will either be overrun (economically or militarily) or thrown into utter chaos.
When we place “conservative” constraints on something even though we have better information we are applying an undue “pressure” to limit the advance of a certain technology. These pressures for nuclear energy come from us and from the generation that developed the technology. The anti-nuclear movements of the 1970’s and 80’s have a play in them too, notably, Waxman, Markey and Reid and their predecessors.
The effect of a restrictive EPZ requirement on a utility is not a trivial issue. If there are population centers within the EPZ the infrastructure needs to be sufficiently built up to accommodate evacuation. Drills need to be run, plans maintained, interface to significant levels with local state and federal agencies. All these things come at a cost. That cost is what restricts mPower from being put on Charter street.
I had the privilege of touring that facility after my first midshipman cruise. I thought way back then, “Damn what if we put a reactor in here. How wonderful that would be.”
The level of protection is also determined by the source term. IRIS used some novel arguments to make the case against a large EPZ. Those arguments fell on deaf ears in the NRC. After Fukishima those ears are even more deaf. PRISM had different arguments, back in 1994 the NRC said, we’ll see.
Our nation is at war, war to ensure our oil supply does not get interrupted. I spent 10 years of my life watching and dodging super tankers. We loose those it’s over.
Nuclear energy is the only non fossil source that has the power density needed to be able to used for process heat applications. So I hope you see that advancing nuclear power, at least for me, is a continuation of the mission I had under my commissioning oath. We are at war our very survival depends on where we get our power from.
@Cal – You get it. My experience is similar, though I served on submarines that did not have to do too much tanker watching or dodging. We were “hide with pride” sailors so I had a lot of time while “poking holes in the ocean” to think about the meaning of a fuel tank that ran out VERRRRRY slowly and did not need to be refilled for 14 years. As a financial guy in DC, I got a real good look at the books for maintenance and training for both conventional and nuclear ships and realized just how false the stories were about the cost comparisons that make nuclear look like a luxury. I happened to be on the OPNAV staff during a major run up in oil prices and saw the effect that had on the budget and on all other priorities.
In my high school days, President Ford (or was it Nixon) introduced a phrase regarding energy independence that never took off, but it resonated with me, he said it was the “Moral Equivalent of War.” I think that the talk show hosts at the time had a ball with the acronym, but who cares what they think? This is serious stuff and you and I both know the lengths that our political leadership is willing to go to protect access to petroleum supplies.
In my humble opinion, that is all just about access to Saudi cash – we would not need much imported oil or gas if we built a fleet of nuclear ships (not just Navy) and if we had continued to build nuclear plants at the rate that we sustained for the period from 1963-1973. We have a lot of “trees” to plant and we are late in doing that. The best time to start is NOW.
(oops, wrong figure, that should be 178 million not 192 million…)
I am an emeritus professor of biology, microbiology and immunology were in my bailiwick. The LNT model does not make much sense to an immunologist. One would expect that all life would evolve mechanisms to tolerate the range of naturally occurring radiation on the planet. The LNT assumption that cancer incidence would follow a linear regression from Hiroshima-Nagasaki bomb levels all the way to zero is incredible in the light of modern biology and evolutionary science. We now know that radiation hormesis mediates beneficial effect on health in humans. Investigators have found that small doses of radiation have a stimulating and protective effect on cellular function. Many mechanisms have evolved that negate LNT regression to zero, such as radiation induced DNA repair enzymes, induced enzymes that prevent oxidative DNA damage, killer T-cells which eliminate damaged cells that could lead to cancer and apoptosis. Apoptosis a mechanism by which a damaged cell kills itself by releasing a bag of self-digesting enzymes.
On-going exposure to sunlight results in a tan that gives a measure of protection from U V damage to the skin. The above mentioned mechanisms certainly may function to provide protection to all cells exposed to on-going low to moderate levels of ionizing radiation.
“One would expect that all life would evolve mechanisms to tolerate the range of naturally occurring radiation on the planet.”-John
I agree. As discussed in the “Radioactive Wolves” thread, nature thrives quite well in the exclusion zone around Chernobyl. There are still negative effects, however.
“Investigators have found that small doses of radiation have a stimulating and protective effect on cellular function.”-John
I am somewhat familiar with this phenomena. From what I understand, this is not actually hormesis, at least in the sense that pro-hormesis types mean. For instance (using the tan analogy), a tan can help keep you from getting burned, but that doesn’t necessarily mean low doses of sunlight can’t give you skin cancer. But it is beneficial, and very interesting.
I don’t quite see how the other effects necessarily preclude LNT, but I hope you are right.
“a tan can help keep you from getting burned, but that doesn’t necessarily mean low doses of sunlight can’t give you skin cancer.”
There in a nut-shell is the type rationale underlying the continued use of LNT for policy making – and why this cannot be claimed as science.
What is being asserted here borders perilously close to a form of “argumentum ad ignorantiam” that is claiming a proposition is true because it has not yet been proven false.
…and a slippery slope argument is almost always wrong. I don’t know who you are debating. I do not claim it is true. In fact I have stated multiple times, it is uncertain.
Because ‘uncertain’ within a policy framing context only invokes the Precautionary Principle which in this case has deleterious impacts going from increased costs for nuclear energy to women not getting mammograms, and now I see, parents not letting their kids get dental x-rays.
LNT is a false model that persists because of politics, not science.
If by “politics”, you mean the safety policy that we be safe more than half of the time, then yes.
No by ‘politics’ I mean ass-covering and protecting the interests of the radiation priesthood that depends on continued acceptance of LNT for their jobs.
There is a point here that should be made about probability theory that has lead to a significant amount of confusion and error over the last 200 years.
Fisher, Bohr, von Neumann and countless others are of the “traditional” or rather “orthodox” school of logical inference. They are formally known as frequentists, that is to say for them probability is the frequency of something that we observe after an infinite number of experiments. Probability is a property of the object.
The other school initiated by Laplace, resurrected by Jefrey’s, and honed by many others Gibbs, Cox, Jaynes to name a few. Are what can be said as “subjective” or Bayesian. The Bayesian school of thought is that probability represents the degree of knowledge that we have about the occurrence of some event. It is plausible inference. We use Bayesian inference in risk informed regulations for nuclear reactors. PRA can be done under a frequentist approach, but its scope is limited and it is very cumbersome.
What does a lecture from some Mo about probability theory have to do with our understanding of low dose response?
Short answer: Everything.
Under a Bayesian framework we can easily test the hypothesis of Dr. Tjostern and many others compared to the LNT/DDRF model. We can see which has value. We can be honest with our data and not rule out a whole series of data using DDRF 2 based on the Hiroshima survivors. We can incorporate the cellular repair effects of radiation observed by medical physicists. The elegance of this framework is that it allows us to see what is important and what is not important. If something is not important it falls out of the analysis.
I offer a challenge. I can build a model under which we can test the two hypothesis of the effects of low dose radiation. I need the data set of Chen and Hwang, along with the bomb survivors, and the radiation workers, at the minimum. I will do a side by side comparison using Wald’s Bayes factor. May the distribution with the lowest entropy win.
My understand though is that there isn’t good data. Radiation workers tend to be younger and healthier; bomb victims are Japanese, and the exact dose that any one person who got cancer is uncertain.
Another problem is the statistical variability from other types of cancer is large in comparison to what we expect to see from low doses. Let’s say we measure 1% higher (or lower) cancer rates. Well the average lifetime cancer rate is 40%. That’s just the average. It could be quite a bit more or less depending on who you are. Is 1% significant?
There are lots of cases where a big double digit percentage reduction in cancer death rate is observed for low doses.
https://atomicinsights.com/2011/04/fear-of-radiation-is-killing-people-and-endangering-the-planet-too.html
“T.D. Luckey (Luckey 1997) lists numerous data from humans irradiated with low-level radiation that confirm results from animal studies and other research described in his two classical books on radiation hormesis (Luckey 1980, 1991). These human studies comprise 13 million person-years of low-level radiation with robust statistical consistency. They show the irradiated populations with lower cancer mortality than the unirradiated controls by the following ratios:
U.S. Army bomb test observers: 77.4%
Canadian bomb test observers and Chalk River clean-up crew: 87.5%
U.S. nuclear weapons plant workers: 59.8%
U.S. nuclear shipyard workers: 65%
British energy and weapons workers: 28.3%
Canadian atomic energy workers: 85.7%
Los Alamos laboratory employees: 77%
Observers at Operation Crossroads (Bikini bomb tests): 65.9%”
This seems significant to me. But I’m not a rad scientist.
@ Ajnosek. We’re not interested in the acute radiation region. We want to know about low dose rates such as they occur through operation or accidents of nuclear power plants. I think it is pretty obvious, on biological grounds, that overwhelming the body immune and repair systems with bursts of radiation causes damage increasingly with the dose.
You say young people naturally don’t so much cancer. Yet here is what your source contradicts in the abstract (i can’t access it unfortunately)
“all solid cancers combined were shown to exhibit significant exposure-dependent increased risks in individuals with the initial exposure before the age of 30, but not beyond this age.”
So they should have seen a considerable and increasing cancer incidence earlier on. Why does the early result show a lower and reducing cancer incidence with time? How do you explain this?
I read about the DDREF before. Seems rather arbitrary. In fact trying to capture this effect in a factor wouldn’t be scientific – we are clearly not talking about simple linear relationships where you can apply a correction factor, we are looking at threshold effects and the biological realities of the immune system.
“We’re not interested in the acute radiation region.” -Cyril
I only mention it because you brought up the deterministic effects of acute doses of aspirin. Deterministic and stochastic health effects work in different ways.
“So they should have seen a considerable and increasing cancer incidence earlier on. Why does the early result show a lower and reducing cancer incidence with time? How do you explain this?” -Cyril
I think you misunderstood. People younger than 30 were shown to be vulnerable to solid cancers from the radiation. I am guessing these risks are just snapshots in time. I expect the opposite effect unfortunately: continuous monitoring of this group as they age will give cancers more time to masticize.
No, you’ve misunderstood. If the people younger than 30 are vulnerable to cancer, this means more cancer incidence (otherwise it is a silly unsupported notion). “vulnerable” implies more cancer incidence or lethality.
If you read the earlier Taiwanese study, you’ll see graphs of reducing cancer incidence. Not just lower at first, but getting ever lower with time. This is the opposite of what you’re stating: that cancers have more time to masticize.
How do you explain this?
“If the people younger than 30 are vulnerable to cancer, this means more cancer incidence”–Cyril
That is what the (updated) study says. Although DV82XL has lobbed some “the study didn’t account for (fill in the blank)” accusations. I tend to think that is very possible, since most these studies with significant results have these types of issues, including probably the ones you dug up on radiation workers.
Nevertheless, I have confidence in the major scientific organizations to take these things into consideration and give us the current state of knowledge and robust conclusions.
Actually I agree that there are studies purporting to see evidence of radiation hormesis that are sketchy in those areas too. But two wrongs don’t make a right.
However the debate is not between LNT and hormesis, but rather between LNT and a threshold model, and here there are studies done comparing low and high background radiation areas with good controls that support the threshold model.
” I have confidence in the major scientific organizations to take these things into consideration and give us the current state of knowledge and robust conclusions.”
So what? We don’t and it seems that you are the one trying to convince us. An appeal to authority, won’t cut it.
Ajnosek, you didn’t answer the question or perhaps didn’t understand it because I may have been unclear about it.
If you agree that the study says people younger than 30 are more vulnerable to cancer, then my point is that it is strange that a generally younger population had a reduced cancer incidence over time, over quite a long period in fact. 19 years to be precise. That makes no sense at all, whether the study correctly or incorrectly looked at age distributions etc. 19 years is plenty of time for increased cancer incidence to show up, and if the people are younger we’d see a stronger increasing trend than the general Taiwanese population. We see the exact opposite.
I am talking about figure 1 in the earlier Taiwanese study:
http://www.ecolo.org/documents/documents_in_english/low-dose-Cobalt-taiw-06.pdf
This declining trend in cancer mortality cannot be explained by incorrect accounting of age distributions etc. The low starting cancer mortality, in the first year, can be explained by a younger population, yes. But not the strongly declining trend.
So I hope my question is now clear: how do you explain the declining cancer mortality trend?
“People younger than 30 were shown to be vulnerable to solid cancers from the radiation” That is NOT shown by this study at all. Coming to this sort of conclusion on the bases of this evidence is simply not supportable.
That Taiwanese study has been roundly criticized for failing to control for other carcinogenic insults caused by life habits, occupation, and socioeconomic status as well for not establishing family histories for the sample. When working raw comparisons with national averages is just not good enough to draw any valid conclusions.
From the study: “On the other hand, all cancers combined, all solid cancers combined were shown to exhibit significant exposure-dependent increased risks in individuals with the initial exposure before the age of 30, but not beyond this age.”
Did I misspeak somehow?
Are you referring this updated Taiwanese study? I know the original had that issue, but I thought that was the genesis of the update…
Yeah, I recall reading that study. It has been a while, but my impression was that it had all the hallmarks of a data dredge. In other words, the conclusions that it draws are about as accurate as claims that green jelly beans cause acne.
Hah, its funny. I didn’t hear any of you anti-LNT guys crying foul when the shoe was on the other foot. Cryil even cited it.
I don’t think it’s a “data dredge”. But great cartoon, by the way. I love that one.
Well, ajnosek, that’s your opinion, and you’re entitled to it. Based on what you’ve written here, I’m not convinced that you would recognize a data dredge if you saw one.
In any case, it’s weak tea to impugn me for not criticizing a study that I neither referred to nor commented on.
Data dredges or fraudulent researchers might explain the results from the earlier studies. I couldn’t find any evidence of this so didn’t seem like a valid accusation.
It’s not just the Taiwanese study though. Very similar results arised from the USA nuclear shipyard worker studies, rad lab workers, bomb workers/plutonium handlers etc.
In fact there are lots of cases and studies that simply disprove the LNT. Here on Atomic Insights there have been many articles written on this, for example see this excellent piece by Ted Rockwell:
https://atomicinsights.com/2011/04/fear-of-radiation-is-killing-people-and-endangering-the-planet-too.html
Those numbers really speak for themselves.
Look at Table 3 in the study (DV8 has provided a link to the manuscript below). There we see roughly 50 standardized incidence ratios (SIRs) with confidence intervals for various types of cancer. (There are actually more CIs than that, but they are not all independent.) Of these various cancers, only three give results that yield a significantly positive risk: leukemia (male), based on six cases; thyroid (all), based on seven cases; and lymphoma, based on five cases, three in men.
If we assume that there is no effect to observe, we would expect — given the test for significance, p ≤ 0.05 — to see two or more “significant” results from chance alone (a 1 in 20 chance). So the results are not all that surprising.
This is what I mean by data dredge. Break the cases up into little units, so that you get a greater chance to observe a significant result based on a small number of cases. If that isn’t enough, the authors then break down the results by age, which gives an even greater chance of finding something significant. (And why is the cutoff set at 30 years old? It seems rather arbitrary.)
So what makes it into the conclusion? Was it that the result with the narrowest confidence intervals — all cancers, male, female, and combined — showed a significantly lower risk? No. Here is the conclusion from the abstract:
Am I the only one who sees that slight of hand that’s going on here?
Yes I am referring to the updated study. Full text here:
Cancer risks in a population with prolonged low dose-rate γ-radiation exposure in radiocontaminated buildings, 1983 – 2002
Estimated doses, questionnaire and self reporting do not make for hard data sets. These are particularly unreliable in this context for both cultural reasons, and potential legal issues.
Finally, compared to the geographic reference population, the study population had lower incidences of all cancers combined, (table 3) making me wonder about the utility of this study to show anything.
Thank you for this DV, I was quite anxious to read that updated study.
As Brian Mays points out above, the conclusion in the abstract is not representative and I dare say, contradicted, by the actual data they present in the PDF itself.
Amazing.
So I read through the study, and I disagree with cyril’s, Brian’s, and DV82XL’s first set of comments. I somewhat agree with DV82XL’s second set above.
DV82XL’s first comment: The methodology of the study compares people of the dataset to themselves, not to national averages. Therefore, while lifestyles with-in the data set can still vary (i.e. a smoker could live in an essentially no-dose apartment), this should largely control non-random differences. I imagine you realized this when you shifted your emphasis on your second comment.
Brian: The results of the study are Table 4. Table 3 exists for information, and it is expected to have discrepancies because it does not control for differences in lifestyles, etc. such as that DV82XL was originally pointing out. Both DV82XL and I originally thought the study methodology was going to present Table 3 as the results…they are not.
Table 4 shows that TOTAL cancer incidence for ALL people receiving more than 5rem is 40% higher, but with a large confidence interval. When you focus on those under 30 (which was ~80% of the dataset) TOTAL cancer incidence was x5 higher. Still a large confidence interval though, but still high enough to be significant. I believe the reason that the under 30 group is so much more significant is because barely anyone under 30 years normally gets cancer, including those in this study below 100 mrem.
Cyril: The study is consistent with the information in Table 4, see above.
DV82XL’s second comment: I agree that estimated doses as opposed to dosimeters is not precise, but these bins are very wide. Errors in the dose estimates (e.g. because some guy misremembers that he was home 5 days a week, not 3 days a week) would contribute much to errors in the results. Of course though, hard data sets would be better. Also, the overall lower cancer incidence is also interesting, but I don’t necessarily see how that dramatically diminishes the worth of the study.
I understand the statistical gymnastics that were done in that paper, unfortunately these tend to devalue the results to the point of making any conclusion drawn very soft.
The worth of the study has to be seen in context. As science, well we’ve all seen much worse it is true. My issue is the weight this study is given – it’s an interesting study, but it is hardly definitive – and the results could be massaged in a justifiable fashion to come to a very different conclusion. Thus to hold it up a some justification for policy-making is a bit of a stretch.
Broadly, most of the studies done on small samples in this area, regardless of the conclusions drawn, are suspect because quite frankly they are riddled with major sources of error.
It is not acceptable to simply pick the ones that support one view and dismiss the others as tripe, and this is what is happening. What we need to look for are well designed studies that use hard data and long baselines, and if these are not available, they should be done.
I have questions regarding the DDREF. This is based on high dose rates data from atomic bomb survivors, right? So how can it accurately correct for dose rate – seems to me it can only correct for varying total dose for an inherently high dose rate exposure (an atomic bomb).
Also the DDREF numbers or general dose rate correction factors look suspiciously arbitrary, eg 2 or 5 or 10.
This appears to be a very meager if not flawed treatment of a critical issue.
Also the DDREF numbers or general dose rate correction factors look suspiciously arbitrary, eg 2 or 5 or 10.–Cyril
Any information for low-doses is sketchy. The use of the DDREF is no exception.
LNT is based on high dose rates, extrapolated down to low doses. When low dose data arrives that doesn’t fit LNT, the BEIR solution is to introduce an extra factor from nowhere, called DDREF, and divide the expected health effect by that much.
A distressingly low number of people have noticed that this means that the LNT model is not actually being used for these cases, and in fact this is an admission that LNT does not apply below some value, making it meaningless to apply in that range, with or without an adjustment.
Joffan – Unfortunately, some people have noticed and don’t like it. The Germans, for one, have effectively declared war on the DDREF. For example, look at this [comment] from the Federal Office for Radiation Protection of Germany on a 2006 draft for some ICRP recommendations:
I just found a reference that had been tickling the back of my memory, what I see as a smoking gun on using the DDREF as an excuse to keep hold of LNT at low doses
It’s from no less a body than the ICRP, the abstract for their Publication 99, Low-dose Extrapolation of Radiation-related Cancer Risk. The relevant quotation is:
“Unless the existence of a threshold is assumed to be virtually certain, the effect of introducing the uncertain possibility of a threshold is equivalent to that of an uncertain increase in the value of DDREF, i.e. merely a variation on the result obtained by ignoring the possibility of a threshold.”
Tranlsation: DDREF is a bodge that avoids admitting to any threshold, no matter what observations are made.
Joffan (continued) – Sorry, the comment is available online.
Joffan (continued) – Consider another article out of Germany that purports to show, using epidemiological evidence, that the low-dose-rate, moderate-dose exposures result in higher risks than the linear extrapolation from the atomic bomb survivor data. The main purpose of the paper, of course, was to do away with the DDREF.
Joffan (continued) – This paper led to an editorial (unfortunately behind a paywall) that suggests that it’s time for the DDREF to go. This editorial, by the way, was written by none other than one of the coauthors of the notorious Wing et al. “reanalysis” of the Colombia study of cancer deaths immediately following the Three Mile Island nuclear accident.
It’s no surprise where they sit on this issue.
Which decision would be fine, if it meant that they are intending to re-examine the evidence and see if LNT really works in that zone – which it wouldn’t.
But of course they won’t do that; they’ll just carry on using LNT without supporting evidence.
Unfortunately, no. Richardson was calling for the equivalent of DDREF = 1 (i.e., simple linear extrapolation from high dose without any kind of modifier), and he used the German paper I cite above (Jacob et al) as “recent epidemiological evidence” that supports this change in radiation protection policy.
Also, I’m not sure if this has been referenced here, but here is Calabrese’s criticism of NCRP.
http://www.radscihealth.org/rsh/docs/Correspondence/NCRP136/JrCcmts.htm
The job-matched and age-matched nuclear shipyard worker study showed strong hormesis, but was omitted in the NCRP based on flawed rejection criteria. The NCRP accused the shipyard study for non-stochastic occupational selection factors while assuming radiation induced cancer to be a stochastic process!!! The NCRP people are contradicting themselves in suggesting non-stochastic factors to explain stochastic cancer deaths.
The British radiologists study showed similar results to the US nuclear shipyard workers, and the earlier Taiwanese results also showed similar correlations.
I am not a radiation scientist or health physicist. I just want to find out the truth.
ajnosek – I guess that’s why all of the quantitative results in the abstract are expressed as standardized incidence ratios — that is, they came from Table 3.
That sound impressive until you realize that the results are marginally significant at the p ≤ 0.05 level, and it is based on only seven to ten cases of cancer.
@jmsdep,
You are answering a different question. Your response is directed at the question of, “Can radiation induce cancers?”
You will find little argument here that this is a correct statement.
The question that is being debated is a different one. It is the statement, “There exists a threshold for radiation exposure and that low doses of radiation are non linear and negligible in impact and risk.”
Please qualify your recent post with the dose rate for these studies (not just cumulative dose, but average daily dose rate) I will almost guarantee that it is on the order of 0.2 Sv/day dose to the lungs. The range that we are looking at is on the order of 2 mSv/day.
We might add too that the health and safety standards for uranium mining (all mining for that matter) in North America are much higher than they were in those days. Nor can the fact be ignored that old practices exposed miners to several respiratory insults, not just radioactive ones, and this too must be taken into account.
Abel, I was precisely answering to those two questions Septeus7 asked :
“How do you know that increase rate of cancer was from the uranium mining. How did you exclude other factors such as smoking?”
Septeus7 seemed to be casting doubts on the very fact the uranium miner studies really proved the link with increased cancer rate.
But on the question of the threshold, I actually believe those studies do globally point toward the existence of such a threshold.
And if you are right that the dose was in the order of 0.2 Sv/day dose to the lungs, then it’s actually casting doubts on the ratio that BEIR VII uses for high dose effect, because even with that high a dose, the effect was not completely obvious, for the miners that were smokers, there wasn’t such a huge increase in lung cancer. Hope any confusion is cleared.