Health effects of nuclear radiation in plain language

45 Comments

1. It’s surprising that more science hasn’t been done on the effects of radiation. That seems to be changing, and it is always better to have more facts.

   1. There has been more done on the effects of low doses of radiation than it seems if you only read the executive summary of papers on the subject. The people paying for the research generally are looking for support for their view that all radiation is dangerous, so that is what the researcher says in the summary. Researchers gotta eat too, you know. While the body of the paper proves just the opposite.
      For much more on the subject, I suggest you start with http://hiroshimasyndrome.com/

      1. how frustrating it must be for the nuclear industry lobby to be outspent on propaganda by wealthy urano-phobes willing to pay off researchers to write what they’re told. It must be of great relief to the impoverished nuclear industrialists that there remain a few world governments who can see through the commissioned summaries, and reach the happy decision to wear any health risks there may be, giving the poor atom splitters a second third chance at meltdown.

   2. Agreed. Not just the more spectacular high intensity stuff either. We exist in a universe defined by radiation. It is everything. The slower decaying of some of the more complex instances of matter probably making up our entire existence.

2. This is the most amazing quote.

   “If we compare the amount of natural (endogenous) DNA damage that occurs in one year, which is ~ 8766 h/y x 10,000 = 90 million changes per cell, with the damage caused per cell by natural background radiation, which is about 0.24 cGy/year x 100 = 24 changes, we can see that the cell damage from background radiation is relatively negligible.”

   1. Yes, it looks like things have been blown completely out of proportion from many angles. And the overused “completely out of proportion” not giving due credit to how incredibly out of proportion it is.

3. The Free-Radical Fallacy acerca Ionizing Radiation:
                  Demonstration People’s Claim Is That a Senseless, http://www.ratical.org/radiation/CNR/FreeRadFallacy.txt this article refutes work Billen.
   The LNT model is wrong, we now know better bystander effect and genomic instability so we know that the LNT model underestimates the risk at low doses

   1. Jhon,

      I’m somewhat confused about the argument here. As I read the paper, it argues that ionizing radiation damage is more severe than free-radical damage but how does that jive with your statement that LNT underestimates low dose risk?

      I’m also confused as to the distinction between accumulated dose versus dose rate in the paper. My understanding is that the LNT model is based solely on accumulated dose but I didn’t catch where the paper makes that distinction.

   2. Jhon; thanks for the interesting reference. I would like to see Jerry Cuttler’s take on this, especially parts 3&4.

      Does anybody know of a critical review of this essay?

   3. Actually, Jhon, what we have learned about the bystander effect and natural genomic instability caused by ordinary metabolism shows that Gofman’s theories about repair mechanisms were wrong.

      Repairs are not “amazingly fast,” they often require 24-48 hours to be fully complete. This argues against a fundamental tenant of Gofman’s belief that fluoroscopy studies involving doses of 1.5 to 7.5 cGy per dose with total accumulations of 150 cGy to 1000 cGy provided evidence that there was no threshold or safe dose of radiation.

      He also proposed that repair mechanisms only work within individual cells; he did not recognize that bystanders are activated by ionizations to form repair sites that isolate and fix other cells.

      LNT does not “underestimate” damage at low levels and low dose rates. It overestimates harm in the range below the threshold and ignores the fact that doses in a certain range stimulate repairs and adaptive response enough to provide a net benefit to human health in the same way that moderate exercise and proper doses of vitamins and minerals make us healthier and longer-lived.

      1. ok buy, on the other hand, you know any document to make a review of this http://www.ratical.org/radiation/CNR/FreeRadFallacy.txt ?

      2. which is supported to say that the bystander effect and genomic instability does not increase the risk that estimates the LNT model? You have material to share about it?

         1. Sure. “Responses to Low Doses of Ionizing Radiation in Biological Systems” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2657485/

            The LNT was initially justified by geneticists under the “target theory” which assumed that every ionizing ray or particle could permanently damage (mutate) the genetic material in living tissue. When radiobiologists pointed out that living tissue had evolved responses to insults and damage like the ionizations that are a normal part of the metabolism that enables life, Gofman came up with a theory about “tracks” that acknowledged the existence of repair mechanisms.

            However, he used a mathematically-based argument with a few now disproven assumptions to state that incomplete or unrepairable situations still allow a single track to pose the risk of cancer-causing mutations. He did not acknowledge that the existence of biologically-evolved repair mechanisms, even if imperfect, would — by necessity — reduce the slope of the dose response curve at low doses compared to high doses where the repair mechanisms would be overloaded.

            Instead, Gofman argued that incomplete repairs proved that high dose data could be extended into the low dose region. His asserted theory has been shown to be wrong, even though he was a very credible messenger with a lengthy resume of previous accomplishment.

            1. Thx Rod.

            2. according to what I understood the bystander effect damaging acts but also helping repair in conclucion, I do not understand the role of the bystander effect and whether it is “good” or “bad”.

               1. In an evolved organism, with an effective immune system, the overall “bystander effect” is to repair or eliminate damaged cells. That effort rarely, if ever, fails as long as the insult is not sufficient to overwhelm the defenses. Science that enables us to actually measure what is happening at the cellular level in living tissue shows that low level radiation stimulate the immune system response and leads to an overall positive response over a certain range of doses.

                  Some stubborn radiation opponents, when faced with this evidence, will then ask the fall back question of “what about the children?” Children have developing immune systems and are generally quite resilient to “that which does not kill them.” (As my friends the Marines would say.)

                  Other stubborn opponents will appeal for extra protection for the most vulnerable of us, but for some odd reason they don’t ask for bread to be made illegal because some of us are celiacs or to outlaw peanuts or shrimp because there are people who would experience severe allergic reactions if they consume even tiny quantities of those ordinarily harmless substances.

            3. Interesting discussion. Correct me if I’m wrong Rod, but my understanding is that the LNT model assumes an accumulated dose. I didn’t catch where the paper you referenced even touched on that. It seems that all discussion and explanation is in regards to dose rate, not accumulated dose.

               1. @Ike Bottema

                  The LNT’s assumption of accumulated dose effects is based on a no repair, physics/mathematical model that was known as the “Target Theory.” That model assumes that any “hit” on a cellular nucleus can cause an inheritable mutation, so all you have to do to predict the eventual amount of damage, which increases the probability of genetic harm, is to count up the hits.

                  That theory doesn’t care how long it takes to accumulate the hits.

                  It is not biologically correct; accumulated dose is meaningless.

                  As long as doses are received in a manner that allows time for biological repairs and adaptive response to work, there is no accumulated harm. There have been some very long-lived (85 years and more) nuclear professionals who routinely accepted doses as high, or even a bit higher, as the 1934 ICRP standard of 2 mGy/day throughout their long careers (not every day, of course.) A few examples are Glenn Seaborg, Lise Meitner, George Sanford, and Ray Haroldsen. ANS Nuclear News obituaries are full of other examples.

4. Science denial propaganda.

   “The threshold dose at which a gene turns on and the dose at which it turns off is different for each gene.”

   The threshold dose for any gene is in the hundreds of eV range or less (the bonding strength). Ionizing radiation is in the 1 keV range or higher. So a single photon or particle of ionizing radiation can mutate a gene.

   Facts are stubborn things. So are science deniers.

   1. Bob your beloved LNT fails, now that we know bystander effect and genomic instability can say LNT underestimates the risk

      1. How much risk? Relative to what?

      2. HA! We’ve known about the bystander effect and genomic instability for more than a decade. They occur at low and high doses. LNT doesn’t underestimate the risk.

         LNT has been the scientific consensus for more than 50 years.

         P.S. Are you also a Creationist? An Astrologist?

         1. I am not a creationist, I am not an astrologist, but you are a dogmatic, LNT underestimates the risk (bystander effect, genomic instability)

         2. I’m not sure “consensus” is dispositive proof for a given position or theory. The Ptolemaic Model of the geocentric solar system was “consensus” for over a thousand years, and in the end it didn’t matter. Even in the modern era of physics, Lord Kelvin and his peers were absolutely convinced and had reached a scientific consensus on the existence of the luminiferous ether, which was thought to be essential for the transmission of light waves. So appeal to consensus can sometimes lead you down the wrong path.

         3. bob,
            as you know it does not underestimate the risk?

5. Makes sense. This morning I accidently poked myself with a knife, drawing a little blood. Not a big deal, I know the skin will mesh back together and the damage will be repaired. But a large knife wound would not heal so easily. Seems biology is fairly good at fixing little problems.

   1. Actually biology is fairly good at fixing little problems, but not perfect.

      That’s why we get cancer (or do you deny that people get cancer?).

      That’s why life evolves (or do you deny speciation?)

      Facts are stubborn things.

      1. Bob,

         You’ve completely failed to understand the argument. The argument is that certain levels of radiation cause biological defense mechanisms to activate, and when those defense mechanisms activate the damage decrease (no where does it say they eliminate it completely.) Therefore having certain low levels of radiation is beneficial since it activates the defense mechanisms, and decreases the damage.

         What makes sure that this doesn’t happen? Life evolved with radiation. Therefore it needed to evolved defend mechanism. To many defense mechanism is a waste of energy so they aren’t on all the time. Really this is no different the getting a tan when you spent a lot of time out in the sun.

         There is definitely some stubbornness here but it isn’t facts.

      2. Bob,

         A few quick questions:

         1. Do you dispute the number of observed changes per cell listed (90,000,000 per cell per year versus 24 per cell per year from background radiation)?

         2. Do you deny the existence of cellular repair mechanisms?

         3. Are you certain that repair mechanisms are NOT triggered by certain levels (thresholds) of radiation? If certain, how did you develop such certitude?

         Feel free to answer with “this is outside my area of expertise”.

         Thanks,
         EntrepreNuke

         1. @ EntrepreNuke,

            I have been asking Bob Applebaum those types of questions for years. He has never responded. He always pops in, calls everyone a creationist and then drops out. He refuses to engage in a debate over facts, and simply dismisses any challenge as pseudo science.

6. In am living proof of low level radiation not being harmful. I have worked at Indian Point since 1983. I am a mechanic there. I have been down in the reactor cavity fixing the fuel transfer cart. My electric dosimeter was not beeping, but it was at a straight hum. I fixed valves in the ion exchange gallery in 5 REM fields. I have helped out at other Entergy nuclear plants for outages. My life time dose is around 15 rem. I have diabetes ,kidney problems, and other minor problems that a 58 year old man gets. None of it because of radiation. NO cancer!

   1. @Tom Clegg

      Tom, not to one up you but to add further support to what you say, I was shown the accumulated dose of one individual at my plant and it was over 80 Rem. When I say shown, I mean I saw the legal record right on the computer, ie., not hear-say. I believe this individual is in his 60’s and that his life time dose may be even higher as he did a lot of work outside the country in the early days of nuclear power (this part is hear-say).
      I don’t fear low levels of radiation and it is high time we raise the legal dose limits.

7. Rod, I think it’s a good time to get an interview with someone who studies the impact of radiation in biological terms, I imagine a good option would Dr Sylvain Costes, the a been studying with his laboratory radiation from human biology, exogen biotechnology is your new endeavor and perhaps their results can give us light on the effects of atomic radiation

   1. In that vein, I’ve been wondering why there haven’t been studies undertaken to assess genetic mutation and cancer rate differences between populations living in high background radiation areas versus populations living in lower background radiation areas. Or perhaps there have been, in which case it would be good to have such results published here.

8. In the past Rod has posted essays that note the distinction between single point DNA damage, which can be repaired using the information stored on the undamaged strand, and the much more serious double strand break.

   The rate of double strand breaks from non ionizing sources is much lower than single point breaks, and the radiation field needed to match the double strand rate is far lower than for single point damage.

   The author lumps them all together under the term “measurable endogenous DNA changes” hiding this important distinction. That makes me suspicious.

   1. According to the following source, naturally caused DSB’s occur about once a week per cell, while background radiation (3 mSv?) increases this rate by about 0.1%.

      http://www.columbia.edu/~jeh1/mailings/2014/NuclearRadiationSafety.2014.pdf

      I guess this implies that a dose-rate of 150 mSv/year would increase the natural DSB rate by about 5%.

      150 mSv / 3 mSv * 0.1% = 5%.

      AFAIK, such a 5% increase should have already shown up in the various radiation exposure studies done through the nuclear era. Has it, though?

      1. His hit and runs on this post are almost certainly complete, but I would like to know what Applebaum’s response to this particular comment would be.

         Rod,
         Could you try to get in touch with Applebaum and request that he not post at all unless he agrees to at least return and respond to other commenter’s reasonable questions for him. It seem that he will show up without fail any time that radiation health effects are discussed in a post, but he limits his appearance to a few posts the first day……….then never returns.

9. Another piece of the cancer puzzle emerging indicates most cancer arises in stem cell division errors. Not that environmental factors are unimportant but they probably also play a diminished role, especially at low levels:

   “Our study shows, in general, that a change in the number of stem cell divisions in a tissue type is highly correlated with a change in the incidence of cancer in that same tissue,” ( http://www.theguardian.com/society/2015/jan/02/two-thirds-adult-cancers-bad-luck )

   1. Note fig 2 also in this discussion from the study ( http://www.riskscience.umich.edu/bad-luck-cancer-media-get-wrong/ ). The non-specific, generic “carcinogen” stand alone, catch all descriptor is likely becoming a sloppy term that shouldn’t be used in reasonable discussion especially at levels where the mechanism and effects are more firmly grasped.

   2. The correlation of stem cell divisions with the incidence of cancer and the large variation in stem cell divisions in different tissues is an interesting and significant new finding.

10. There is some more discussion of the study John T Tucker just mentioned here:
    http://freethoughtblogs.com/pharyngula/2015/01/03/cancer-bad-genes-or-bad-luck/

11. I have the sense that alpha radiation in the lungs, such as, from the inhalation of Rn-222, would be more harmful than a much higher dose of gamma or x-ray radiation to the outside of the body, such as, from a chest x-ray. Anybody have any thoughts on that?

    1. The answer is “it depends”, but it can be an “apples and oranges” discussion so it is not straight forward unless you are very specific about how you define harmful equivalence. For one thing once you turn the x-ray machine off (or leave the exposure area), the cell damage stops. But with internal exposure the damage process continues until it either all decays (including radioactive daughters) or your body eliminates it biologically (biological half life). And every organ has a different sensitivity to damage, different retention time biologically (thyroid captures Iodine), etc. The discussion shifts to a “body burden” for each organ for each isotope, to try to set an external dose equivalent comparison.
       In your question example the most harmful depends on the actual dose from the Rn-222 and how that dose equates to an equivalent external x-ray dose. It’s stuff for “look-up tables.”
       That’s a trained nuke operator level of understanding. The other message we get is internal contamination is problematic, so read the area signs posted, and correctly wear the protection equipment, and just avoid the problem.
       Rn exposure is a known natural hazard, and significant in some geographical areas and also some mining areas. If you have a concern much is written and available, just google it.

12. I just wanted to add that a lot of the time when a cell experiences radiation damage such as a DNA double-strand break, it will undergo programed cell death – also known as apoptosis. Therefore it’s possible that more severe DNA damage such as that caused by radiation will not lead to cancer because the cell responds by basically committing suicide while single mutations caused by DNA replication errors when cells divide are more likely to cause cancer. (I don’t have the exact numbers but the consensus in the cancer field from people like Bruce Ames and Bert Vogelstein seems to be that it’s the number of times that cells divide that increase the risk of cancer.)

13. There is three times as much interest in molten salt reactors as in the cancer study. Is this because the cancer study omitted prostate cancer? There were other omissions as well, including breast cancer, brain cancer, skin cancer, kidney cancer, spleen cancer to mention a few. The study is clearly a work in progress and does not destroy the validity of LNT at this point in time.

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