There’s a lot of discussion of radiation from the Fukushima plants, along with comparisons to Three Mile Island and Chernobyl. Radiation levels are often described as “<X> times the normal level” or “<Y>% over the legal limit,” which can be pretty confusing.
Ellen, a friend of mine who’s a student at Reed and Senior Reactor Operator at the Reed Research Reactor, has been spending the last few days answering questions about radiation dosage virtually nonstop (I’ve actually seen her interrupt them with “brb, reactor”). She suggested a chart might help put different amounts of radiation into perspective, and so with her help, I put one together. She also made one of her own; it has fewer colors, but contains more information about what radiation exposure consists of and how it affects the body.
I’m not an expert in radiation and I’m sure I’ve got a lot of mistakes in here, but there’s so much wild misinformation out there that I figured a broad comparison of different types of dosages might be good anyway. I don’t include too much about the Fukushima reactor because the situation seems to be changing by the hour, but I hope the chart provides some helpful context.
(Click to view full)
Note that there are different types of ionizing radiation; the “sievert” unit quantifies the degree to which each type (gamma rays, alpha particles, etc) affects the body. You can learn more from my sources list. If you’re looking for expert updates on the nuclear situation, try the MIT NSE Hub. Ellen’s page on radiation is here.
Lastly, remember that while there’s a lot of focus on possible worst-case scenarios involving the nuclear plants, the tsunami was an actual disaster that’s already killed thousands. Hundreds of thousands more, including my best friend from college, are in shelters with limited access to basic supplies and almost no ability to contact the outside world. If you’re not sure how to help, Google’s Japan Crisis Resource page is a good place to start.
Edit: For people who asked about Japanese translations or other types of reprinting: you may republish this image anywhere without any sort of restriction; I place it in the public domain. I just suggest that you make sure to include a clear translation of the disclaimer that the author is not an expert, and that anyone potentially affected by Fukushima should always defer to the directives of regional health authorities.
xkcd 
@Mr. Oizo
I have probably been too zealous in pointing out what I see as flaws in the chart. I’ve been zealous requesting changes because the chart’s use has expanded beyond its original intent — or so I believe. This being the case, I would like to see it revised and my reasons are in earlier comments.
As for ‘censorship’ the moderator has chosen –for reasons undisclosed and beyond me– to suppress information submitted in response to issues brought up. That the information is suppressed does have me wondering about motives.
Have I been intolerant? Bigotamous!? I don’t think so. While I’ve disagreed with some, I’ve backed up my opinions with technical arguments and left personal attacks for others … for you as it seems.
Sp, Mr. Ozio, let me close by congratulating you on being the first in more than 400 comments to resort to personal attack. All of the rest of those who have commented — including those I’ve disagreed with — should be proud for what they have not done.
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The chart in general is correct (although I doubt there is an x-ray that gives only 1 uSv (see http://www.xrayrisk.com/calculator/calculator.php?id=10)), but the 100 mSv as least amount shown to cause measurable cancer increase is a very rough figure. We have measurable increases in cancer from the following, all well known facts: CT scans (widely reported in New York Times and elsewhere). Radon (at levels far less than 100 mSv): lots of money spent every year on reducing this hazard, not even mentioned here. And finally iodine 131 that caused most of the cancers from Chernobyl, which cannot be measured simply by mSv because it is concentrated and focused by biological processes. This has to be taken into account. The problem with Chernobyl is that no one is mentioning the vast amounts of money spent to reduce exposure across Europe. If the discussion that took that into account, we would understand that just talking about doses and distances is not enough. The cesium concentrated in lots of wild foods also was and even now continues to be a problem in some areas. This will also be a problem in Fukushima. Around 273000 people worked on controlling the Chernobyl disaster and have not been adequately studied (the Soviet Union had them on military-service-like pensions, I think Chernobylets was the term for these veterans, just like Afganets for those who fought in Afghanistan). Many have died of cancers, but this goes unreported and under-assessed (see one attempt in the book Chernobyl: message for the 21st century, Elsevier, 2002, pp. 7-17). A final, very appropriate element that has been left out here is the amount received by people exposed to the blast and residual radiation from Hiroshima and Nagasaki. Let’s try to put these all together, not just hide the leaking radiation from the reactors among the medical uses and natural exposures. –Nathan Light
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It would have been interesting to put on the chart the amount of Sv Louis Slotin received on May 21, 1946, the result of a horrifically dangerous experiment. That number is 21, or nearly half the Sv of being directly next to Chernobyl.
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I sent this chart to my dad, who is a pretty serious expert on this stuff. He replied to tell me that the chart has been making the rounds among his colleagues at NIH. Well done!! He sent me a detailed discussion of the current disagreements among medical experts about the relationship between low dose radiation and cancer (the chart’s suggestion that 100mSv is “clearly linked” to cancer, which others have also commented on). Randall, if you are interested, shoot me an email and I’ll forward his reply to you.
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I love you. Seriously. Serious love from me.
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@Quora
Not exactly, but the Fukushima thing is not ongoing. The situation is becoming more controlled every day. Three of the four damaged reactors have been reconnected and are functioning normally, and the leaks are being found and plugged.
We are taught that there are three facets to radiation doses: time, distance and intensity of exposure. If the dose is low enough, or the distance is high enough, the other two become irrelevant. If the dose is small enough, it doesn’t matter how close you are or how long you’re there. If you’re far enough away, it doesn’t matter how strong it is. Time is the only exception, but the lower the other two factors are, the longer the time of exposure can be without causing harm.
@everyone
What we seem to be forgetting (most of the people here) is that this chart is not meant for professional use in diagnosing radiation poisoning, or the dangers of radiation around Fukushima, it is simply meant to dispel the panic of people who are NOT IN JAPAN who seem to think (for some reason) that they are in some sort of danger from it by giving them a measurable representation of the threat. Some people simply won’t listen to reason, and need a visual aid.
FYI: The half-life of iodine-131 is slightly over 8 days. The amount of time it takes for a cargo ship to travel from Japan to the mainland United States is (gasp) eight days. Even if your produce was irradiated when it left Japan, it will be safe for consumption by the time it gets to the Americans. Sorry, I don’t know about other countries.
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PS. He even admits that he’s not an expert and that there are probably mistakes in his chart, and to refer to his references for expert information. Cut him some fucking slack.
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Yeah. Huffington Post totally ripped you off.
http://www.huffingtonpost.com/2011/03/29/radiation-levels-visualiz_n_842188.html
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@ViviWannabe:
True, there is no immediate threat of any explosive radioactive leak, but Fukushima is hardly “more controlled every day”. Rather, every day, Tepco discovers some new serious problem that will delay bringing the plant under control. E.g., this week:
* fatal levels of radiation were discovered in water that is pooling under three of the reactors — but this came to light only after workers were sent in and subsequently needed to be hospitalised with radiation burns to their feet;
* the water runoff from the plants is close to filling the facility’s underground tanks — yet more water must be pumped in to keep the reactor vessels’ temperature and pressure within safe limits. Tepco is desperately trying to find somewhere else to store the runoff.
While power has been connected to the control rooms, this does not help much, as the control mechanisms and monitoring systems are largely nonfunctional, and cannot be repaired until the radiation levels in the plant have been considerably lowered.
Nor does it help that Tepco has demonstrably failed to communicate problems in any clear or timely fashion (even to their own press officers) — as seen in inconsistent reporting of radiation levels just over the past few days.
The company has a long history of covering up problems (e.g. regarding a 2002 leak, and the effects of a 2007 earthquake directly under another reactor site), and it is not surprising that the Japanese public views Tepco’s ongoing assurances of safety and control with considerable skepticism.
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@ViviWannabe:
What linger said + the discussion is not limited to Japan. Last sunday, in Germany two parties experienced a serious defeat at elections due to their stance towards nuclear plants.
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@DK
If your dad’s information will fit in the comments or can be made available somehow, I know I’d like to see it.
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Can you update the chart to show the radiation now that reactor 2 has melted down onto the concrete floor? Also the 1+ sievert an hour of the water pooling outside the reactor building. Make sure to distingush between simple exposure to radiation vs the risk caused particulates of radioactive isotopes.
I suggest you use units of bananas per hour.
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I’d have loved if you’d added the TSA “backsplatter” scanners to the list of exposures for comparison 😉
Seriously though, great chart.
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hello
I would like to translate this chart to French
if you agree, tell me the best way to proceed.
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Hi,
I’ve translated the chart in italian, that should be ok because it is released as public domain. I’ve used a font named volter goldfish, that looks like pretty the same.
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I’m pretty sure I saw a French version of this somewhere.
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@Vashra
One backscatter is about half of one banana.
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Responses inline..
ViviWannabe says:
March 29, 2011 at 6:07 pm
@Quora
Not exactly, but the Fukushima thing is not ongoing. The situation is becoming more controlled every day. Three of the four damaged reactors have been reconnected and are functioning normally, and the leaks are being found and plugged.
>>> 4 of the 6 are irreparably damaged, and no attempt will be made to repair them.
We are taught that there are three facets to radiation doses: time, distance and intensity of exposure. If the dose is low enough, or the distance is high enough, the other two become irrelevant. If the dose is small enough, it doesn’t matter how close you are or how long you’re there. If you’re far enough away, it doesn’t matter how strong it is. Time is the only exception, but the lower the other two factors are, the longer the time of exposure can be without causing harm.
>>>In *my* training, I was taught that we reduce exposure via time, distance and shielding. And that distance was the best protection, because of the inverse square rule.
@everyone
FYI: The half-life of iodine-131 is slightly over 8 days. The amount of time it takes for a cargo ship to travel from Japan to the mainland United States is (gasp) eight days. Even if your produce was irradiated when it left Japan, it will be safe for consumption by the time it gets to the Americans. Sorry, I don’t know about other countries.
>>> nor do you know about half-lives. After the passage of a half-life, 50% of the activity remains. It’s not ALL gone, only half of it. Those of us who have been trained use ten half lives as the ‘rule of thumb’ for no measurable activity remaining. For I-131. this would be 80.4 days.
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I don’t see why everyone is going all “randall is evil for spreading misinformation herpaderp” and whatnot. He’s been doing what he’s always been doing with these charts: compiling known available scientific information and making it accessible so that the general public is better informed (or entertained). If you think the government trying to kill us by falsifying radiation data so we all die, so be it. If you aren’t scientifically educated and would rather enjoy getting emotionally charged by conspiracy theories, then go right ahead, just bring your qq somewhere else.
Anyways, great chart.
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Good chart. Wish I’d thought to do something like that back when I worked in the college physics labs; the pre-med students were sure the radioactivity lab exercise was going to kill them. I reassured them that the lab was completely safe, as long as they stopped writing in their lab manual while wearing contaminated gloves…and then chewing on their pencil.
Actually, considering that, I think the chart would have just made them afraid of bananas.
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@esmeyny — if you want to see misinformation, just go to CBSNEws.com, where their headline writer tagged their article about traces of plutonium being detected in soil samples as “toxic plutonium pools”. No joke. And it was clear from the comments that people were reading the headline more carefully than the article. (Which wasn’t all that great, but didn’t make that claim).
And then, they turn around and offer a photo essay on the “8 terrifying symptoms of radiation sickness” — you know, a bloody nose, a sunburn, someone puking, sleeping — all taken from iphotostock, no photojournalists were employed.
Pure fiction, rather than journalism.
@ViviWannabe — I disagree with your assessment that the situation is not ongoing and is getting more controlled. It’s more complicated than that.
Progress IS being made. But at the same time, conditions are becoming harder — more radiation releases, more fatigue, shortages of qualified personnel as they are rotated out due to exposure. Meanwhile, we don’t know what’s going on in those reactors, or even the pools.
There are reports of neutron releases suggesting transient recriticality. The quality of the reports is poor (“neutron beams”) and I’ve not been able to find confirming data or reports, but they’ve been cited by the IAEA (Denis Flory, in a conference in Vienna). This may just be a rumor — but so long as there’s so much uncertainty that an IAEA official would express concern about such reports itself says the situation is ongoing.
http://us.mobile.reuters.com/article/healthNews/idUSTRE72T78120110330 (I won’t link to all the blogs declaring that there have been 13 “neutron beams” — always 13, always “neutron beams”. If anyone has attributable facts one way or the other, please get them out there!)
It will be “ongoing” until the course forward is understood and the progress is predictable. We’re a long way from that point.
Time is working both sides of the street on this one. As things cool (both radiologically and thermally), it helps, but as time passes with more and more releases on the site, and more strain on the workforce, it raises the danger of a more catastrophic release, or even just continued releases at the current levels, which are already having a devastating effect on the Japanese economy, and the lives of thousands of individuals.
It’s ongoing, until people either know it’s safe to return to their homes, or when, if ever, it will be.
It’s ongoing, so long as crops and milk are being dumped because of contamination, and that contamination continues to arrive.
The real thing to fear, or at least what I fear, is not getting zapped by gamma, or my poor malfunctioning thyroid taking up I-131. It is what happens to Japan, and the world economy, as a result of this.
Japan is now short on electrical power, and an economy based largely on manufacturing. I worry about what will happen to my in-laws if Japan undergoes inflation. I worry about the effect on the US economy as parts don’t arrive.
Mostly, I worry about all those displaced people from the tsunami, who are now joined by thousands more, and whose government is now distracted from helping them by this disaster.
It’s ongoing, even if the remaining reactors are on a path to cold shutdown. A matter on which we have no assurance whatsoever.
@Randall — great chart, and great to see it cited all over. I think it really helps.
@Paul — I sympathize with your concerns, but really, I think you’re overreacting. I don’t think readers are reading it in the way you are. I think people take these things as illustrative signposts in the spectrum, and as notable points where assumptions may be surviving — bananas!
I don’t think most readers have the motivation to make the kind of comparisons that worry you. And I think that those of us who might make such comparisons, are able to distinguish between short-term and long-term doses, and recognize the limitations of such comparisons, and of such diagrams.
The real message is in the broad overview — the vastness of the number of orders of magnitude between that first little square, the person sleeping next to you, and the final end point that has everyone in terror.
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@Bob Kearns
I hesitate to drag this on, but this is what I refer to when I say misleading numbers in the chart have indeed mislead:
http://www.guardian.co.uk/commentisfree/2011/mar/21/pro-nuclear-japan-fukushima
If I were to revise earlier comments, I would have bared my teeth less in the early comments and remained focused on the most egregious problem I see in the chart:
“Average total dose from the Three Mile Island accident to someone living within 10 miles (80 uSv).”
As noted in news reports, geographic deposition of radioactive fallout is very uneven. Since health effects from radiation depend only on local levels of radiation, reporting the average level over a large area only covers up the real health risks experienced in the ‘hot spots’ near a nuclear accident. I. e. the average radiation exposure near TMI is as meaningful to health predictions as the average income of bar patrons is relevant to their prosperity when Bill Gates walks in the bar. I. e. in this case the average is meaningless.
Now I don’t think Randall did anything more than cite the industry/NRC published number, but I believe this published number – even if it is ‘correct’ – was created only to be picked up and repeated and thereby mislead – just as it mislead George Monbiot at the Guardian.
I’ll leave off with a link to testimonials of people who lived near TMI in 1979. You can decide if the cited average exposure of 80uSv at TMI is meaningful for judging health exposures or not.
http://www.tmia.com/node/118
(Be sure to read the Bill Peters story. It looks to me like lethal levels of radiation wafted over the Peters’ property over the course of a few days. At least is was lethal to a dog, cats and a lot of birds. Had the Peters family not evacuated, I suspect it would have been lethal to them too.)
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The issue is distance. “Ellen” says it here:
“The easiest way to avoid getting a dose is to not be in the field in the first place. This is made easier by the inverse square law” — http://people.reed.edu/~emcmanis/radiation.html
Imagine ingesting radiation material (dust in the air or from food). These heavy massive alpha particles, full-on atoms, are now shooting up your cells at close range. How does it “affects the body”? It would be “made easier” to explain this by calling the law the square law not the inverse square law.
PS. Chernobyl’s radiation caused a million deaths not a few.
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Thanks for posting this, I hope it’ll clear up some of the misconception surrounding “the radiation levels are over NINE THOUSAND”.
Also I want a bananaphone now.
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I am curious about your comment on the chart that cell phones don’t cause cancer. What source do you have for this statement? Please read Disconnect, by Devra Davis. The book describes a “disconnect between common opinions about cell phone safety and the actual data” – David Servan-Schreiber, MD., PHD., author of Anticancer.
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@george
If you’d kept reading, you’d have seen that I addressed that at the bottom of my page. There is a way to convert inhaled and ingested amounts of radionuclides into Sv which are comparable with this chart.
The inverse square law is based on something similar to Gauss’s law in electrodynamics, and only holds as long as the object can be treated as essentially a point source. It blows up as you approach the object — obviously, nothing emits infinity amounts of radiation. So different measures are needed, and using it as an argument for how bad stuff you ingest is is disingenuous at best.
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ViviWannabe says: “The half-life of iodine-131 is slightly over 8 days. The amount of time it takes for a cargo ship to travel from Japan to the mainland United States is (gasp) eight days. Even if your produce was irradiated when it left Japan, it will be safe for consumption by the time it gets to the Americans.”
Well it is a good thing this person is not in position of authority because they can’t do the math. Half life refers to the time it takes 50% of an unstable element to decay to something else. If the amount of contamination is more than 2 times the allowable amount then after 8 day, in this case, it still exceeds the allowable contamination. Of course near Fucushima contamination could far exceed twice allowable.
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It is true that mobile phones and other radio devices do not emit ionising radiation—and are therefore outside of the scope of this chart. However, it is not a given that they cannot cause cancer. Ionising radiation is by no means the only carcinogenic force out there. Electromagnetic radiation certainly does have adverse effects on animal tissue (the usually ½ to 2 kilowatt emissions of microwave ovens being an obvious extreme example), even if non-carcinogenic (which, afaik, has yet to be determined conclusively).
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This is a great chart, and thanks for making it.
It isn’t perfect, and I don’t expect it to be. It’s just meant to give non-scientists a manageable context for the radiation information being mis-used by the media. I’ve tried explaining to friends the difference between milli- & micro sieverts, rads, curies, etc; but unless you plan on giving them a course in physics, toxicology and a few medical courses, most people won’t understand the finer points.
@ the critics here: stop trolling the guy. The chart is great. It’s science, not rumor; cites sources; and it works.
#thatisall
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@Ellen I will look at that part, I did not read it. I know about the Dirac delta function and yes I thought it might apply in this case. I was just trying to be more metaphorical and asking why distance away was more important (as it would be in say in radio when you have the near and far field) than say distance close up (as in nuclear exposure where there is no near field). Anyway dose to the cell is 500mSv but to the whole body is 5 x 10^-11 mSv. (see http://rense.com/general93/decon.htm) That is a factor of 1e10 .. or 1e5 times more close up to a cell or distributed across 1e10 cells in the body. (Humans have 1e14 cells). I apologize if I sounded rude before with all the quotes.
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see also http://ocw.mit.edu/courses/nuclear-engineering/22-55j-principles-of-radiation-interactions-fall-2004/lecture-notes/alph_n_bystand.pdf (“The authors concluded that total track length deposited in nucleus is the critical factor”)
And now I don’t think the inverse square law even applies. You are dealing with a bowling ball of an atom, not electromagnetic waves or absorbed dose. The equation is mass * velocity and it doesn’t stop till it hits something.
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This article I link below uses the chart to ‘put things in the right perspective’, whatever right might mean in this context (I suppose the opposite of left, rather than wrong).
http://www.sott.net/articles/show/226550-Worse-Than-Chenobyl-When-the-Fukushima-Meltdown-Hits-Groundwater
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Btw, using this for my speech and debate class. Thanks!
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Thanks so much for posting this and spreading the enlightenment. I have no idea how the read the chart, but gosh, the colors sure are pretty.
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George wrote:
PS. Chernobyl’s radiation caused a million deaths not a few.
No, you’re exaggerating the death toll by a factor of roughly 250. From the Wikipedia article on Chernobyl:
The Chernobyl Forum concluded that twenty-eight emergency workers died from acute radiation syndrome including beta burns and 15 patients died from thyroid cancer, and it roughly estimated that cancer deaths caused by Chernobyl may reach a total of about 4,000 among the 600,000 people having received the greatest exposures.
There are controversies concerning the health effects (read the Wikipedia article), but no responsible people are suggesting a death toll anywhere near a million.
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just a little something
1. half life means exactly that – half life. people seem to get the impression that radioactive substances are neutralized past their half life. no, only – guess what – half of the substance is.
2. it’s pretty funny seeing the media source this chart and claiming their information is accurate, despite randall’s reiterative warnings that the information is far from perfection… and the fact that this chart was made to _dispel_ misconceptions due to misuse of information by the media. herpaderp i love this world
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Thats a lot of information. Good Work.
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Sorry to be off-topic, but the 3-D is laggy for me. Someone please give me an off switch for it.
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totally off-topic but still have to say this:
pretty pretty please do NOT transfer all the comics in 3d! totally annoying plus with some of the older ones it doesn’t work properly and messes with the writings! please please please do not do this! was funny for the latest comic, but for all the others thats not really an improvement.
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