Low-level radiation exposure less harmful to health than other modern lifestyle risks

From the “I thought sure Fukashima was going to kill me” department

Oxford Martin restatement finds that risks from radiation exposure are extensively studied and small relative to smoking, obesity and air pollution

UNIVERSITY OF OXFORD

Human populations have always been exposed to ionizing radiation, and more so in modern life due to its use in medicine, industry and the armed forces. Whilst the risks to human health from medium and high-level radiation are relatively well-understood, the risks at lower levels are less clear. Mixed messages about the safety of low doses of radiation from different sources have created confusion for the public and for policy makers.

In a new study, published today in the Proceedings of the Royal Society, a team of experts from the Oxford Martin School at the University of Oxford have compiled the evidence on health risks from low-level ionizing radiation, adding a new nuance to the debate. The restatement is intended to better inform policy decisions and show where crucial gaps in knowledge lie. It clarifies the scientific evidence available from a variety of sources, and ranks them as to how much they enjoy consensus support from the scientific community. The paper concludes that the overall risk to human health from low-level radiation exposure is small, particularly when compared with general risks from modern society, such as obesity, smoking and air pollution.

Professor Angela McLean, lead author and Co-Director at the Oxford Martin Programme on Collective Responsibility for Infectious Disease, said: ‘We know a great deal about the health risks from radiation thanks to exceptionally careful studies of groups of people exposed to different levels from nuclear bombs or accidents, medical exposure of patients, naturally occurring sources (such as radon), and workers in the nuclear industry and medicine. From these studies it is clear that moderate and high doses of radiation increase the risk of developing some types of cancer.’

The team illustrate the size of this increase in risk by using the following example. 100 individuals were each briefly exposed to 100 mSv (millisievert is the measure of radiation dose), then, on average over a lifetime, one of them would be expected to develop a radiation-induced cancer, whereas 42 of them would be expected to develop cancer from other causes. To put 100 mSv in context, the low dose from a CT scan of the whole spine is 10 mSv, while the average dose from natural background radiation in the UK is 2.3 mSv each year.

To build on the insights gained from this study, further research will be conducted to better understand the genetic healthcare implications of radiation exposure and the biological basis of the damage from radiation to DNA and cells.

Professor McLean said; ‘Despite the depth of our knowledge, there are still many unknowns. Even the best designed epidemiological study finds it hard to distinguish between no extra risk and a small additional risk at low levels of exposure and we have to make some important assumptions here, particularly for the purposes of radiation protection. For example, no human study has conclusively shown an increase in hereditary disease in the children of irradiated parents, but radiation protection calculations assume some risk is present because of evidence from large animal experiments.

‘There is also a great deal of work being undertaken to investigate the biological basis of the damage from radiation to DNA and cells, but it is still not clear precisely the steps by which a dose of radiation might lead to cancer, sometimes decades later’.

###

NOTES TO EDITORS:

The full paper, “A restatement of the natural science evidence base concerning the health effects of low-level ionizing radiation” can be downloaded at http://www.oxfordmartin.ox.ac.uk/policy/restatements/.

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124 thoughts on “Low-level radiation exposure less harmful to health than other modern lifestyle risks

  1. Sanders generally cherry picks studies that disagree with LNT. But if you look at all of the studies, like the above study from Oxford, they say ” At sufficiently low doses, all models are consistent with available datasets.”

    • “At sufficiently low doses, all models are consistent with available datasets.”
      That’s just funny. Basically it says the individual response are indistinguishable from background. Real helpful that.

      • Thanks for the link, but I am puzzled by the lack of use of the Taiwan data in this report. Is there an opinion that the studies were flawed? As a minimum, there should be a comment one way or another. How can a real world long term exposure of 8000+ people be ignored? No such human trial would ever be allowed, so it is the most important data set we have. Exposures went from 10X to 100X normal background levels, depending on proximity to radioactive steel rebar.

        Can anyone help?

      • Part of the problem is that there is no way to accurately calculate exactly how much radiation each person received.
        That makes it easy to throw out such a study, especially if your goal is to prove that radiation is harmful at any level.

      • Mark, that leaves the health statistics of the 97% reduction of all forms of cancer as compared to the general public, which reverts towards normal over 15 years since vacating the buildings. Does that not count as worthy of mention, if only to shoot it down due to some methodological error?

    • We are all exposed to galactic radiation from deep space that we cannot avoid. It causes a gradual degradation of our DNA, one of the reasons human life is limited to a maximum of 120 years, no matter what we do.

      • pyeatte:

        ” … one of the reasons human life is limited to a maximum of 120 years, no matter what we do.”

        What’s another reason?

    • Given that non-radioactive isotopes of caesium are poisonous, then of course ingesting it must be bad for you. The biological half lives of various elements before they are excreted and the nuclear half lives are important, but if the radioactive element is poisonous too, you have a serious problem which has nothing to do with radioactivity.

    • cesium is a problem because it is chemically incorporated into the body.
      Which makes it different from most other sources of radiation.

    • Just fort the record, we did not learn anything Chernobyl that we did not know before.

      Do not expose children to I-131. Children in Japan were not exposed because the design allowed time for children be evacuated.

      A simple timely warning at Chernobyl to shelter in place would have reduced I-131 exposure 90%

  2. If you think about what a single gamma ray does as it rips thru a cell nucleus, it does 1/100 of the damage that 100 gamma rays do. They usually result in double strand breaks in DNA which are usually repaired with error prone mechanisms. That is to say, the double strand break is repaired but the sequence is altered, it is mutant. If that sequence is in an oncogene, (ignoring other cancer forming mutations), you have the basis for cancer.

    So, in a nutshell, that why most agree on the LNT model.

    • Of course that’s incorrect. The vast majority of DNA lesions (estimated at 10^4-10^6 per cell per day) are repaired accurately.

      • the reason CRISPR technology works so well is that only error prone mechanisms are used to repair those lesions.

      • The issue with radiation-induced cancer is the time-lag – noted in the extract from the article above. If the radiation causes the mutation in an “oncogene”, why is there a 30-40 year lag in the incidence of cancer? Direct increases in cancer incidence do follow the error-prone DNA repair model nicely, but not the long-term higher incidence. The standard explanation that it just takes time for these tumours to appear just doesn’t work when you look at the particular tumours that are found. Various theories are being considered, but it is not a simple problem to study as we don’t have any short-term experimental models for long term effects.

      • You have also misunderstood the genome editing procedures (CRISPR/TALEN etc) as these use a specific template which triggers the homology directed repair mechanism in order to produce the desired modification to the DNA sequence. This is the very basis for the specificity of CRISPR as a gene editing procedure and not just another mutation mechanism.

      • Rob, the most common reason for the lag is thought to be that cancer is usually caused by two hits, and the second one is years later, the Knudson hypothesis.

        Since I use CRISPR monthly if not weekly, I feel I understand it. When we use a “specific template which triggers the homology directed repair mechanism”, we need to provide that template. Irradiated cells don’t have access to that template; too bad a cell couldn’t just use the template on the homologous chromosome, but they apparently don’t.

    • …So, in a nutshell, that why most agree on the LNT model….

      Right. That sounds like a good reason to propose the LNT hypothesis.

      Now, how well does it match observation? Because it doesn’t matter how compelling your theoretical reasons are for holding a hypothesis – if it doesn’t match observation it’s WRONG. See https://www.youtube.com/watch?v=0KmimDq4cSU

    • Except that the cell then undergoes apoptosis. Or it is killed by other mechanisms. The body doesn’t just allow mutations to sit around and multiply. It is only when cell mutate to avoid apoptosis and the other mechanisms that they are a problem.

    • So wrong its not even wrong.

      In fact the response to high levels of radiation is either

      – cell is fine due to using dial strand to ‘repair’
      – in an amazingly small number of cases a viable mutation.
      – in an even smaller number of cases a viable malignant mutation
      – cell death due to massive DNA destruction

      As the actual radiation intensity increases, NOT the duration of exposure, the scale shifts towards cell death as the most probable.

      That is, below a certain intensity the chance of a double strand break becomes almost zero.

      If a gamma ray knocks out a strand, and that is repaired in a day, and then another gamma ray comes along and does it again that is exactly NOT the same as two gamma rays close together in time causing a mutation.

      It is very like degradation in a digital signalling environment. There is a threshold below which severe degradation happens and above which almost no degradation happens.

      LNT is completely discredited, and it only survives as a guideline for legislation because frankly we can achieve incredibly low levels of radiation in nuclear power and medicine. So why worry about extremely tight standards?

      Well for two reasons these days. First of all it backfires. Instead of being reassured by how low the radiation levels are, people say ‘it must be really dangerous if the government says its has to be that low’ and if a minor spill does happen ‘its extremely serious because government guidelines are exceeded’.

      (as an amusing anecdote, my green sister claimed this about Chernobyl: I then asked her if this was the same government that was (according to her) covering up ‘millions of cancer deaths that had never been reported’ post Chernobyl).

      (Except if you have the radiation therapy of course: Typical cancer treatment consists in applying lethal doses to small areas. So lethal that if applied to the whole body they would kill you within a day or so. These can and do cause unrelated cancers in decades that follow, but its better than being dead. Allegedly).

      In short what causes damage is peak intensity, not total dose. Moderate background levels are harmless. Repeated short exposure to high dose is not. Even if the total exposure is the same.

      The only way long term low level exposure has been shown to be harmful is in the case of biological accumulation. In particular natural radon in conjunction with smoking, which destroys the lungs ability to cough up foreign material leads to accumulation of radon decay compounds in the lungs.

      And those decay products are radioactive Bismuth Polonium and Lead – chemically carcinogenic as well as radioisotopes that are very heavy and hard to get out of damaged lungs.

      However radon is not something produced in reactors much.It’s largely natural. It has a very short half life so its gone within a day of most reactor ‘leaks’ .

      LNT was essentially ‘we know radiation in high doses kills, and obviously no radiation at all cant kill, so let’s just draw a straight line between the two, and use that to frame nuclear radiation emission standards.’

      • LNT just says that physics works at low doses the same as at medium and high doses. It is actually the null hypothesis for this question.
        At low doses it is really hard to gather enuf data to disprove that hypothesis, so it stands. Boring but true.

      • Really Skeptical says, “LNT just says that physics works at low doses the same as at medium and high doses.”

        The physics stays the same, but at low doses (and low dose-rates) it’s the biology that matters, including the mechanics of cancer promotion and induction. When the incidence of additional cancers is so low it cannot be distinguished from the natural background rate of cancers, I think it is fair to call it an effective threshold and stop trying to regulate every radioactive atom.

      • “That is, below a certain intensity the chance of a double strand break becomes almost zero.”

        Absolutely wrong. A single gamma ray makes a double strand break not a single strand break. It probably does more damage than that, what with most DNA being condensed in nucleosomes.

        Barbara says, “When the incidence of additional cancers is so low it cannot be distinguished from the natural background rate of cancers, I think it is fair to call it an effective threshold and stop trying to regulate every radioactive atom.”

        Maybe. But it is higher, not the same. That means there are some people who die that wouldn’t normally. You okay with that?

      • Really Skeptical says, “Maybe. But it is higher, not the same.”

        No, we don’t know that. The background rate of cancers is not one single number. It’s a range. When you cannot distinguish an increase against the background, it does not mean there is an increase just because you hypothesize there may be one based on high dose (high dose-rate) data.

      • In response to Really Skeptical’s comment on gamma radiation (low-LET) and double-strand breaks, damage from gamma breaks out in %-type of damage similar to induced changes through reactive oxygen species (ROS) – i.e., only a small percentage of DSBs are induced per Gray of gamma:

        “We are continually exposed to oxidative stress, with as many as 50 000 lesions of DNA modifications [1] induced daily in each cell through reactive oxygen species (ROS), formed as a by-product of aerobic metabolism. Cells have well-developed repair processes to deal with damage induced through oxidative stress as it is vital that the cellular responses are able to maintain genome integrity and stability to minimise the onset of potential tumorigenesis and the ageing process. The identification of the different types of lesion induced endogenously and the free radical mechanisms of their formation have been described in numerous reviews [2–4] and an excellent book by von Sonntag [5]. Ionising radiation also results in DNA modifications in each cell exposed at the fractionated doses conventionally used in radiotherapy. The types of lesion produced via exposure to ionising radiation are, in the main, chemically identical to those formed by ROS [3,4,6]. For instance, ionising radiation induces in mammalian cells around 850 pyrimidine lesions, 450 purine lesions, 1000 single-strand breaks (SSB) and 20–40 double-strand breaks (DSB)/cell/Gy with low linear energy transfer (LET) γ-radiation (Table 1 shows yields of major lesions induced by radiation [3]).”

        Clinical Oncology
        Volume 25, Issue 10, October 2013, Pages 578-585

        Biological Consequences of Radiation-induced DNA Damage: Relevance to Radiotherapy
        M.E.Lomax, L.K.Folkes, P.O’Neill

      • “there are some people who die that wouldn’t normally. You okay with that?”

        Protecting us against everything sets back technology so much it ends up costing lives. But lost opportunity costs are much harder calculations to do. There’s never been good studies to show LNT is scientifically valid theory. People just started using it for risk assessments because it was considered the safest thing to do. Years after that it was declared scientifically valid theory. In fact the original LNT rule – linear no threshold applied to all carcinogens, not just radiation. But it can’t ever be applied, there being so many carcinogens, with epidemiologists being unable to show what is or is not.

        Oxygen is a carcinogen, a proven DNA mutagen. A typical person breathes in about 500g of O2 per day. It is crucial in making ATP, the cell’s energy ‘battery’. It’s essential for life. It’s been calculated some 2% to 3% of O2 breathed in goes astray. About 10g to 15g per day, which is about a 1/3 to 1/2 a mole. Let’s say 2E23 molecules. Divided between ~ 40 trillion human cells. It’s at least 5 billion DNA-mutagen O2 molecules per cell, per day, running amok. Just to put some perspective on this. Without DNA repair mechanisms we’d soon be toast. It’s the double strand breaks we need to worry about. Those are the really hard ones to repair. O2 will be causing single strand breaks; so will most radiation damage. Even most radiation damage is not direct; it’s not hitting DNA. Nearly all radiation damage will be due to ionization of water. So it’s secondary products which do the damage.

    • Actually we do have data on very low doses. People that live in Denver and other high altitude locations receive about twice as high a dose of background radiation than people living near sea level. With such large populations it should be easy to find even small effects, yet none have been found. People that live at altitude do not have higher incidence of the types of cancer one could reasonable expect from radiation exposure.

    • Reallyskeptical

      Your remark is a perfect example of reductionism ad absurdam.

      There are about 10,000 low LET ionizing interactions per second, of the type you luridly describe, in the average human body. Like yours for instance. Every second.

      That’s why LNT is epistemologically shipwrecked junk science.

      And BTW only a tiny fraction of low LET ionizing events will result in a double strand break. This only happens in the rate case that the linear spacing of energy depositions approximates to the interchromasomal distance of about a third of a nm. Unless it’s alpha particles you are talking about. But they do so much damage that they usually kill the cell (so no cancer).

  3. “briefly exposed to 100 mSv”
    The inhabitants of Ramsar receive this dose or higher annually. They’re not dropping like flies.

  4. Well, Marie Curie worked with Uranium and transuranic elements for about 30 years without shielding. She even used to carry test tubes containing radioactive isotopes in her pocket, and she didn’t died of cancer. Also, she gave birth to two healthy children, not obvious mutations.

    https://en.wikipedia.org/wiki/Marie_Curie

    I am not saying that excessive radioactivity is not bad, but the actual risks have been exaggerated.

      • No. Not cancer, but prob’ly caused by radiation:
        From the Mayo Clinic: Aplastic anemia is rare. Factors that may increase your risk include:
        Treatment with high-dose radiation or chemotherapy for cancer

      • “Factors that *may* increase” is not the same as “causes.” The fact of the matter is, they can’t really say what caused here aplastic anemia; a point that even the Mayo Clinic will concede. She may have died of it without the radiation exposure. There are documented cases of people from it that were never exposed to large doses of radiation.

      • Marie Curie was exposed to massive levels of radiation. Her lab notebooks are to this day stored on a lead box. Her radiation induced illness is of no relevance whatsoever to the question if low level radiation (nonexistent) risks.

    • Marie Curie died of aplastic anemia most likely linked to her work with radioactive materials. Although Pierre Curie died in a traffic accident at a relatively young age he was already suffering from what would now be recognized as radiation sickness. Her daughter Irene, also a Nobel laureate for her work on radioactivity, died from leukemia.

      • It is interesting to note that the causes of aplastic anemia are unknown to this day, and it is HYPOTHESISED that exposure to various chemicals, radiation or various viruses MAY be a cause.

        I don’t think anyone has established an open-and-shut cause for any cancer. Most assertions rely of correlation. And since a very large number of people, if they live long enough, will develop a cancer of some kind, correlations are easy to come by.

      • Dodgy Geezer September 14, 2017 at 7:18 am
        I don’t think anyone has established an open-and-shut cause for any cancer. Most assertions rely of correlation. And since a very large number of people, if they live long enough, will develop a cancer of some kind, correlations are easy to come by.

        Since there is a significant delay between exposure and incidence of many cancers correlations are usually the important linkages (as well as animal experiments). Some are very specific though, for example, Studies of women who took diethylstilboestrol during pregnancy revealed that their female children had high rates of the extremely rare adenocarcinoma of the vagina in adulthood. The link between smoking and lung cancer is undeniable.
        There are many more examples in the following paper:
        https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734938/

      • … The link between smoking and lung cancer is undeniable….

        Interestingly, I’ve never seen any proof of this. Just people telling me it’s undeniable.
        And there may be links to all sorts of things. I’m looking for causality. And since there are many smokers who don’t get cancer, the link isn’t as simple as saying ‘smoking causes cancer’…

      • “Interestingly, I’ve never seen any proof of this. Just people telling me it’s undeniable.
        And there may be links to all sorts of things. I’m looking for causality. And since there are many smokers who don’t get cancer, the link isn’t as simple as saying ‘smoking causes cancer’…”

        It appears the evidence would suggest the smoking of the plant isn’t the problem at all, rather the problem seems to be how it’s fertilized (bold mine):

        Abstract

        Among all carcinogenic substances contained in tobacco smoke, Polonium 210 (Po-210), with a half-life of 138 days, is one of the most dangerous, by exerting a devastating, chronic, slow and progressive carcinogenesis activity. The main source of Po-210 in tobacco is represented by fertilizers (polyphosphates) containing radium-226 (Ra-222) which decades to plumb 210 (Pb-210). Through the thricomes Pb-210 is concentrated in the tobacco leaves, where it turns to Po-210, which at the cigarette combustion temperature (800-900 degrees C) reaches the gaseous state and it is absorbed by the micro particles released into tobacco smoke. Thus, smoke becomes radioactive in both its gaseous and corpuscular components and reaches the airways, where, particularly at the branches level and together with other substances, it exerts its carcinogenic activity, especially in those subjects with impaired respiratory mucosal clearance. The carcinogenic risk/one year lifetime of a smoker of 20 cigarettes per day is equivalent to that of undertaking 300 chest x-rays. It is calculated that Po-210 may be independently responsible of 4 lung cancers every 10,000 smokers. During cigarette’s combustion, tobacco smoke is also released in the air, contributing to serious health risks for those exposed to passive smoke.

        https://www.ncbi.nlm.nih.gov/pubmed/19186689

    • Yes, Madame Curie most likely died from radiation poisoning effects. HOWEVER.

      Bear in mind the underlying facts of Curie’s case:

      Extremely high, frequent, long-term, exposure —

      …. She even used to carry test tubes containing radioactive isotopes in her pocket …..

  5. This controversy has been around for 37 years, following the publication of T.D. Luckey’s “Hormesis With Ionizing Radiation.” Hormesis refers to beneficial effects derived from low doses of toxic agents. Arsenic is often cited, since it’s very toxic but medicinal in low doses. Luckey’s thesis went further, however, and the best analog in my opinion is Vitamin A. It’s absolutely essential for human life, but is also highly toxic in large amounts. Europeans have know of this since the 1500s, when explorers became acutely ill after eating polar bear liver (Inuits have known about it forever). Luckey conducted experiments using plants isolated from background radiation to the greatest extent possible. He found that below a certain threshold, they could no longer reproduce.

    The phenomenon is accepted by Japan, France, and China, but roundly rejected by the U.S. and U.K. From what I hear from students going through nuclear engineering classes in the U.S., professors will shut off any discussion of radiation hormesis with a vengeance, insisting that the Linear No Threshold (NLT) theory, which flies in the face of all human experience, is the only acceptable theory.

    • Given the lack of knowledge in the early days of radiation research, the LNT theory was a safe fallback position.
      The problem is that in the years since, we HAVE gained the knowledge, and that knowledge proves that LNT is wrong and needs to be discarded. Unfortunately too many careers are based on LNT.

  6. this layman for decades has said our government promotes an IRRATIONAL fear of “radiation”……..our bodies REQUIRE vitamin D and exposure of skin to sunlight causes the body to make a massive amount of vitamin D yet modern doctors tell people to avoid all contact with the sun light.

    • Depends. With skin conditions like rosacea, sun not good (Also not good is cold/hot air, cold/hot water, cold/hot food, spicy/bland food). Psoriasis, get that skin out in the air and sun is good. I suffer both conditions, thankfully both “healing” and I think mostly due to lifestyle changes and drastic reduction in stress.

      BTW. My first wife, from Ethiopia, suffered vit-D deficiency and needed supplements in Australia. Plenty of sun here.

  7. It’s good to see a study that should help counter the radiation hysteria that pervades our society. However, it’s a meta-study and it’s heavily based on models. The additional risk example is not derived from population studies, it’s an extrapolation of the LNT model. ‘Consistent with datasets’ should probably be rephrased as ‘undetectable’.
    There were a ton of model-derived papers claiming thousands or tens of thousands of deaths from Chernobyl. In reality, there was no detectable effect beyond a relatively small uptick in thyroid cancer.
    It’s way beyond time to admit that we really don’t have data to support the LNT model. That’s NOT claiming that it’s wrong, but it’s at best a hypothesis with lots of interesting data that contradicts it.
    The parallel with climate change is interesting – models that form the basis of very expensive government policy that are not validated in the real world, and where questioning them brands you as a lunatic fringe element.

  8. It was interesting that my oncologist never said he or any other doctors “knew” what caused cancer. He stated the risk factors (I had exactly zero) and that “we do not know what causes this”. Yet the legal system uses “causes cancer” to exact a million pounds of flesh from industries people don’t like (and increase their summer home numbers), the news media pushes the idea that we “know” the cause of cancer, and people are terrified to even breath for fear of a carcinogen being inhaled. It’s, to put it bluntly, insanity. Terrifying people based on data that is manipulated to a desired outcome, and as MarkW noted, when discovery is made that a “cause” really is not, it’s never corrected or taken back. I find it cruel to have people living in fear because there’s money to made or power to be had.

    • It is worse than that. Many cancer charities and health professionals will tell you that “lifestyle factors” cause half of cancers. Quite how they think that makes parents with children with cancer feel is beyond me to imagine. And the evidence, other than smoking? Non-existent except in some dreadful epidemiology paper.

      As this paper says:

      “Even the best designed epidemiological study finds it hard to distinguish between no extra risk and a small additional risk at low levels of exposure.”

      Or as the sensible people say, there is no risk.

      • I was a heavy smoker and then I was diagnosed with – testicular cancer.

        Risk factors? Possibly agrochemicals (I have lived in farming areas fore decades) possibly oestrogen in the water supply from all those pills the ladies chew…

        Not from all those atomic tests and Windscale disasters and Chernobyl’s. Nope. Absolutely not.

  9. …Low-level radiation exposure less harmful to health than other modern lifestyle risks…

    Now that we have computers, and lots of data gathering, it ought to be possible to specify a ‘perfect lifestyle’ which offers the maximum health and minimum risk.

    I suspect that it is something like a home-working vegetarian accountant who has a small vegetable patch and collects stamps for a hobby. Modern government practices will surely start to enforce this regime on all of us shortly…

      • Stamp gum must be toxic or at least a cause of BSE or something horrible because philatelists are a dying breed. Or maybe people just got bored with paying huge amounts of useful money for a scrap of paper. Oh wait….

      • …What if there aren’t enough stamps to go around?…

        Then we have a resource catastrophe, and Prof Ehrlich is FINALLY proven correct…..

    • a ‘perfect lifestyle’ which offers the maximum health and minimum risk.

      I agree completely!
      Sitting in the shade of a coconut palm on a brilliant white coral sand beach. The local workers harvest the coconuts for drinks before they become a falling hazard.
      You get plenty of indirect sunlight to keep your vitamin B levels up and the offshore reefs keep the water calm and the dangerous sea critters away.
      The most dangerous part of the day is moving from the beach to the poolside swim-up bar.

      I could get used to this. All I need is for Government to mandate, and finance my lifestyle.

      • It is vitamin D you mean, not B.
        Besides. there are many B vitamins, not really any such thing as “vitamin B”.

  10. I suspect that it is something like a home-working vegetarian accountant who has a small vegetable patch and collects stamps for a hobby

    Oh dear. had a GF once whose dad was an vegetarian organic farmer who never drank, never smoked, kept out of the African sun (he was from Natal) and in general exercised lots and lots.

    On retirement at 65 his wife persuaded him to leave S Africa and return to England.

    Where he died 6 weeks later of a massive heart attack.

  11. 0. ICRP: International Commission on Radiological Protection
    1. Real-time radiation exposure is computed as an effective dose rate, which is a body-average over the radiative-sensitive organs and tissues, in units of microsievert per hour (uSv/hr). Annual or flight accumulated effective dose is reported in units of millisievert (mSv; Note: 1 mSv = 1000 uSv).
    2. ICRP recommended annual limit for occupationally exposed radiation workers (including aircrew) is less than 20 mSv. If the predicted exposure is less than 1/3 of this limit, the safety signal color will be green – indicating minimal radiation exposure. If the predicted exposure is between 1/3-2/3 of the ICRP recommended limit, the safety signal color will be yellow – indicating that close tracking of individual radiation exposure is advised. If the predicted exposure is greater than 2/3 the recommended limit, the safety signal color will be red – indicating exposure to maximum recommended limit is possible.
    3. ICRP recommended annual limit for public sector radiation exposure is less than 1 mSv. If the predicted exposure is less than 1/3 of this limit, the safety signal color will be green – indicating minimal radiation exposure. If the predicted exposure is between 1/3-2/3 of the ICRP recommended limit, the safety signal color will be yellow – indicating that close tracking of individual radiation exposure is advised. If the predicted exposure is greater than 2/3 the recommended limit, the safety signal color will be red – indicating exposure to maximum recommended limit is possible.
    4. ICRP recommended limit for prenatal radiation exposure is less than 1 mSv annually and less than 0.5 mSv in any one month during pregnancy. The signal indicator color is based on the 0.5 mSv limit. If the predicted exposure is less than 1/3 of this limit, the safety signal color will be green – indicating minimal radiation exposure. If the predicted exposure is between 1/3-2/3 of the ICRP recommended limit, the safety signal color will be yellow indicating that close tracking of individual radiation exposure is advised. If the predicted exposure is greater than 2/3 the recommended limit, the safety signal color will be red – indicating exposure to maximum recommended limit is possible.
    5. The predicted aircrew exposure is based on the current NAIRAS modeled exposure rate multiplied by the maximum annual flight hours for pilots, which is 1000 hrs. If an aircrew member, for example, expects to fly only 600 hrs per year, then multiply the NAIRAS predicted radiation exposure by 6/10. If an aircrew member expects to fly 800 hrs per year, then multiply the predicted radiation exposure by 8/10, and so on.
    6. The predicted public and prenatal exposure for the representative high-latitude flights is based on the current NAIRAS modeled exposure rate multiplied by the average flight time.
    http://sol.spacenvironment.net/raps_ops/current_files/index.html

  12. “100 individuals were each briefly exposed to 100 mSv (millisievert is the measure of radiation dose), then, on average over a lifetime, one of them would be expected to develop a radiation-induced cancer…”

    Ack! Who would submit to such a thing voluntarily?

    • Depends on the benefit. It (allegedly) raises your lifetime risk of cancer from 42% to 43%, and there’s good evidence that even that increase is overstated. If the radiation exposure had a benefit (such as verifying the need for surgery) it might well be worth it. People live in Denver despite a significantly higher background radiation level due to the higher elevation. Despite the theory that there should be an increased cancer risk, it doesn’t show up in the data.

      • If the radiation exposure had a benefit (such as verifying the need for surgery) it might well be worth it.”

        I’m speaking specifically about the research study.

        The authors of this study would have to offer much more in the way of benefits than verifying my need for surgery.

      • The negatives associated with Denver’s elevation radiation are randomly counteracted by the anticancer benefits of all the secondhand smoke :)

      • Don:

        On a more serious note, it seems that depends on the fertilizer used to grow the plant (whatever plant you choose to grow):

        “As high-phosphate fertilizers are applied to tobacco crops, PO-210 is absorbed from the soil through the plant roots.26 PO-210 also deposits on the surface of the tobacco leaf via fine, sticky hairs (trichomes), which bind airborne radioactive dust particles generated during the application of fertilizers.29 PO-210 is thought to be encapsulated with calcium phosphate and lead-210 into insoluble radioactive particles, which are subsequently transferred directly into the mainstream smoke (the smoke that is inhaled directly into smokers’ lungs).”

        https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2509609/

        My understanding is limited, but it would appear that ingesting PO-210 orally isn’t a problem, e.g., fertilizing your tomatoes with phosphate fertilizers and eating them. Rather, the problem arises when the particles are burned as in tobacco or marijuana.

        I *believe* phosphate fertilizers are the most common fertilizers used today.

  13. Thanks Anthony for sharing this. I particularly liked the “restatement” ..a format for non-scientists..appropriate for an old engineer. I would like all risks that, an individual or population are exposed to, or scared of, would be identified so clearly. Especially helpful are inclusion of the magnitude of the risk, the method of determination, and the quality of the studies. Wish all risks, and particularly those where policy is made (and taxed) would be so sensibly presented. Thanks to the authors, too.

    • Like getting a “strong does of radiation” is a realistic worry. How about a strong dose of solar energy causing skin cancer? It is almost scary how often this occurs.

      • The decrease in the number of solar flares means the decrease of the shortest UV radiation and the decrease of ozone.

  14. The only radiation anyone should fear is from radon gas. Every nuclear plant has radiation detectors attached to every employee and are located all around the plant and sound alarms if excessive radiation is present. However, for a molten salt nuclear reactor, it is physically impossible for the core to experience a meltdown, as the molten salt containing the uranium fuel is already in a melted state,as long as the ambient temp is above something like 650 degrees, a temperature that can only exist within the reactor core. Nor does the core contain explosive levels of hydrogen nor is the fuel under any significant pressure – even a rupture of the reactor would not result in the expulsion of uranium fuel into the environment to any significant extent, and once outside of the high temps, the molten salt immediately freezes (when temps are below 450 degrees or something)
    and the fission reaction ceases, without any need for coolant or human intervention.
    No human action is ever required to keep these reactors safe, and no human action can render them unsafe. The laws of physics renders them incapable of hurting anyone. And the high pressure water system used by the turbines is isolated from the radioactive molten salt mixture, which is a combination coolant and fuel core – radiation is present only in that core, nowhere else in the entire system.

    • Please name any operating Molten Salt Reactor.. There are not any.

      What ever benefits you tout, the difficulty of handling molten salt outweighs.

    • There is no reason to fear radon either.

      The EPA does not understand the basics of radiation or risk.

      At a nuke plant in California, I had the task of reducing airborne levels in the reactor building. I measured levels on a daily basis. Often radon levels were higher outside than from fission sources.

  15. In 1955 (Pauling) and 1974 (Asimov) the human health dangers of carbon-14 were described . In particular Asimov calculated that of all radioactive isotopes carbon-14 is the most powerful mutagen simply because approximately 40% of the weight of our DNA is carbon, and when carbon-14 in a DNA molecule decays there is a 100% chance that a mutation will occur. About 1 part-per-trillion of natural carbon is carbon-14, which is sufficient to result in approximately 10 DNA mutations in a typical adult human every 3 seconds.

  16. Radiation does harm by creating free radicals which cause cell damage. Exercise does the same thing. “Excessive” exercise or vigorous but irregular exercise will do the same damage to your body as low level radiation. While many believe radiation exposure damage is cumulative, they do not seem to believe that damage from exercise is cumulative even though it is the same free radicals causing the same cell damage. Go figure.

  17. I am an extreme datum ~3 REM O.W.B.E. in G. Matanoski NSWS 1991 and am personally confident of radiation hormesis. I am 69 y.o.with no notable health issues.

  18. Ionization by galactic radiation above 10 km is growing rapidly. This has a big impact on the chemical reactions in the ozone zone.
    http://sol.spacenvironment.net/nairas/Dose_Rates.html
    The current figures below show the NAIRAS prediction of the radiation exposure quantity related to biological risk – Effective dose rate (uSv/hr) – at several altitudes and flight paths. To put the exposure rates into perspective, one chest X-ray is about 100 uSv, and a CT scan is about 8,000 uSv.

  19. The success of the scientific community in forcing acceptance of LNT, an abundantly disproved and meaningless fallacy, as institutionalised dogma for political ends, is probably what gave them confidence to do the same thing with CAGW.

  20. It is possible that “Sy computing September 14, 2017 at 10:56 am” has come upon the reason for a fact that puzzled Hans Eysenck, the great British (by adoption) psychologist. Sy said:

    “On a more serious note, it seems that depends on the fertilizer used to grow the plant (whatever plant you choose to grow):” and proceeded to give info suggesting that the fertilizer is contaminated with polonium 210, this is deposited on the leaves and absorbed through the roots, and when the leaves are subsequently smoked some of the polonium is absorbed via the lungs.

    Eysenck stated “It was well known that smoking cigars showed much lower correlations with lung cancer and other diseases that did smoking cigarettes, and it is also known, of course, that the tobacco which goes into cigars is cured in a different way to that which goes into cigarettes. Cigarette tobacco is flue-cured, whereas cigar tobacco is sun-cured. Interestingly enough, the tobacco in the countries where there seemed to be little cigarette-linked lung cancer was also sun-cured rather than flue-cured. Sun-cured tobacco might therefore be safer than flue-cured tobacco, but there is no direct empirical evidence for this.”

    I assume that ‘flue-cured’ tobacco is only subjected to hot air and heat from the outer surfaces of the flues and is not subjected to the smoke from inside the flues – which would provide an obvious source of carcinogenic material on the tobacco. That said, there should be no obvious reason to suppose that the curing method affected the carcinogenic make up of the tobacco.

    However, flue curing is more likely to be used when there is more money available for the construction of the curing facilities, and likely there is likely to be more money available for fertilizer. So where sun-curing is used, there would be little or no fertilizer used, and little or no contamination with Polonium 210. [A case of the correlation between A and B being the result of correlation of both A and B with C – C being not normally considered as a cause.]

    I suppose it would be possible for a cigarette manufacturer to experiment with flue-cured crops which had not been fertilized with phosphate based fertilizers, and subsequently to ascertain whether or not there was any difference in the rate of carcinomas between tobacco from the non-fertilized fields and that from fertilized fields. [Those poor smoking mice!] But that is probably too much to hope for, and anyway the establishment has got it firmly fixed that ‘smoking causes lung cancer’, so it would take absolutely no notice of results. [We known what the theory says, don’t confuse us with facts.] As Eysenck said: “I had not reckoned with the hostility of the medical establishment to the introduction of new and disturbing ideas.”

    That last sentence is taken from page 173 of “Rebel with a cause: The autobiography of Hans Eysenck”. The large quotation above in my third para is taken from page 174 of his book, published by W H Allen and Co Plc, 1990.

  21. The is such a thing as zero actual risk. If your exposure is zero your risk is zero.

    My risk of cancer from smoking is zero because I do not smoke. Unless you work at a nuke plant, your exposure to radiation to radiation from the plant is zero.

    Ever notice fear mongers are never so afraid of radiation that actually bother to measure radiation.

    I am afraid of fires and carbon monoxide. I have multiple detectors in our motor home and have installed them in our children’s house. I test them regularly.

    The largest risk factor for cancer is living longer. So I can reduce my risk of cancer by dying in a fire.

    We study risk so we can live longer. This why it is important understand actual risk.

    For example last time I bought diesel fuel in Oregon, I was asked to turn of the frig in the motor home because it is an ignition source. In Oregon, an attendant must pump your gas but the customer can pump diesel.

    So recently a motor home went of in flames at a gas station. This points out the risk of ignition sources at gas stations.

    The other side of risk is benefit. The risk of eating is choking to death. Of course if you do not eat you will die. This will reduce your risk of dying of cancer.

    The other part of risk is how big it is. The goal of risk reduction is to make risk insignificant. If the risk of dying is less than one in a million, we say the risk insignificant. This does not mean that one in a million will die, just that it is a small number compared other risks.

    The risk from radiation is insignificant. Debating how insignificant is kind of silly.

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