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 
Sorry, I did leave out one very important step, which goes between #3 and #4…and which might be of most interest to @atomfullerene.
There are mechanisms which perform error checks and which MAY remove the mutation. Or may not. It really would depend on how well it’s functioning, and it works by checking one strand against the other.
How exactly it picks which strand is the correct strand is left as an exercise for the reader. For the list, what matters is that this either misses the error, or decides the mutated version is the correct one.
The interesting thing is, given the sheer amount of things that could introduce mutations into the genetic code, there aren’t more; the error-checking process used seems to be in fact highly efficient as it seems likely we would notice if people dropped dead as often as the estimated base mutation rate would indicate they would without this process. (While it is definitely not as space-efficient or certain as, say, a ARQ or HARQ system, retransmission of genetic information would be…awkward to conduct. Especially if the sources of your genetic information are dead.)
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I’m confused about the last step, involving the 50 Sv dose received from being next to Chernobyl for 10 minutes during explosion. According to the legend, 100 red squares (4 5×5 blocks, 1 10×10 block) = 1 Sv, and that the red section is equal to 50 Sv. However, I only count about 16-18 Sv in the red section. Are the two sections not supposed to equal? If so, I feel like there should be a yellow square saying “all the doses in the red chart combined”…
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MK says:
March 21, 2011 at 12:27 pm
Great graphic for those of us that need to help others understand.
Hillarious bananaphone reference BTW.
Hilarious, yes, but complete bollocks. The stated dose if about 350 times too big. Sadly this misinformation is what everyone will be repeating from thier barstool for the next 20 years.
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for some reason the chart is removed, I get a blank page.
Considering I’d like to forward this as far and wide as possible, could you fix this ASAP as well?
Ed
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This is great and has been widely shared on Twitter. How about a sequel explaining the different units that radiation is measured in?
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I’d be interesting to see where astronauts fall on this chart – per day on the ISS, total for an Apollo mission, and so on.
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I understand that the amount of radiation coming out of the damaged Japanese reactors is small, but isn’t the chart deceiving? ….Because isn’t “exposure” to a radioactive source (a temporary event) different than inhaling a radioactive PARTICLE (which will continuously radiate you forever)? The radioactive cesium and iodine that are vaporizing out of the plant with the steam are particles of the actual reactor…. I would like this clarified, to understand the REAL (possible) risk.
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As far as I know, inhaling a radioactive particle is dangerous if your body actually absorbs it. This is why they hand out iodine tablets. If your system has enough iodine, it will not absorb the radioactive iodine, which will leave your system fairly quickly. If you are iodine deficient, your body absorbs it and it’ll stay in your body indefinitely, causing much more damage to the surrounding tissue…
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This misses a very important issue, as has every news report I’ve heard: other than for those in the immediate vicinity of a nuclear reactor accident at the time of the accident, it’s not levels of radiation that matter: it’s levels of contamination of air, drinking water and food with radioactive materials.
The end result is still irradiation of your body, but long-term from within, rather than short-term from outside. Both alpha and beta radiation, but particularly alpha, are more serious from within than from outside.
This is all to complicated for a response to a blog! But charts like the one presented in this blog are dealing with radiation, not radioactive contamination – and the latter is the important issue for most people.
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Of course any radioactive PARTICLE becomes less radioactive as it emity radiation. So the exposure depends on the mass you are exposed to and how long that isotope stays in your body.
That is what makes isotopes more or less harmful. Some like to bind to bones or other tissue and stick around, while others pass right through you.
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Thanks Elizabeth! I had a feeling it would be complicated. 😉
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I still think there is something wrong with including bananas in a chart about radiation. There needs to be a chart based on someone like John Gofman’s research that shows the true HARM from various KINDS of radiation for various lengths of TIME, unbiased and truly scientific.
Yes I just found this by searching the internet but it does point out that each KIND is complex. Each kind of radiation has different electron Volts, for example and other things —
Cesium-137 is a “Artificial Radionuclide Produced by the Fission Process”
half-life: 30.174 y
Principle Decay Mode: beta (and gamma)
Maximum energy: 0.51163 Mev – Mev – Milli-electron volts (million)
product of: fission
High energy diagnostic medical x-ray photons………………………….200,000 eV (=0.2 MeV)
Anyway – the bottom line is people are actually being harmed. If you tell someone who is experiencing the harm first hand that the radiation that has harmed them has some relationship to a banana, I’m sure they would want to rip your head off. This chart is offensive to the victims of radiation.
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The chart DOES include the radiactive particles and contamination. The chart shows the radiation dose that the contamination (internal and external) will deliver to a person during the next 50 years. All radiological consequences (including food uptake) are in the chart.
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Actually, this chart does indeed take into account particle type. The unit of measurement, Sievert, does that. The Gray is a measurement of energy deposition. The deposited energy, number of Grays, is then multiplied by a quality factory based on particle type in order to get Sieverts.
As for ingestion and food contamination, I’m trying to find those numbers from recent readings. The belong on the blue part of the chart, however.
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Thank you.
I’m studying Radiologic Technology and a visual aide like this goes a long way toward helping people understand the amounts and different sources of ionizing radiation out there. I especially like the disclaimer.
I’m going to either have this printed on a T-shirt or made into a poster.
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I made a zooming presentation, perhaps giving a better sense of the scales:
http://prezi.com/ocl7xignbv5l/radiation-from-various-sources/
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@Heidi, I don’t think this is offensive to the victims of radiation. It’s a simple fact that everything has some level of radiation. The banana is a good comparison because it is necessary to convey the very exponential nature of this chart.
Consider that it would take about 58,000 bananas to equal one CT chest scan (according to the chart). That’s about 7.5 *tons* of bananas.
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Heidi, I think you either missed the point of the chart or have the worst sense of humor in the world. Possibly both.
According to the chart eating a banana exposes you to ionizing radiation, as does sitting in front a CRT monitor, as does just sitting. This is all true.
The point of the chart is to give a sense of the scale of the dose from a variety of sources of radiation. A banana results in a very low dose of radiation, and is not particularly harmful. This helps draw the line between abnormal/harmful doses and ‘normal’ doses. This chart does not minimize in anyway the damage that is done by excessive exposure to radiation.
Furthermore, the Sv unit used in this chart accounts for the different types of radiation. It is an ‘equivalent dose’ unit as explained here:
http://en.wikipedia.org/wiki/Ionizing_radiation#Units
No one, no matter what their circumstances, should be offended by a chart that attempts to give context to the issue of radiation.
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@Tiago Freire – cell phones do not generate ionizing radiation. Therefore, cell phones generate ~0 uSv, as noted in the chart under the blue blocks.
@Deb Cee – You mentioned radiation from nuclear imaging studies. I assume you mean nuclear magnetic resonance imaging, or MRI. MRI uses RF energy, about 128 MHz, or roughly 10x less powerful per photon than the cell phone I mention above. Therefore, MRI also gives you ~0 uSv.
@P.Solar – I’m sure Randall appreciates some fact checking. However, it doesn’t make sense to get all bent out of shape because one of the smaller quantities in the chart is off by a factor of 10. This is an exponential chart going from 50 nSv to 50 Sv, covering nine orders of magnitude.
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@P.Solar – I rechecked your math. I think you’re off. You gave self-exposure to radiation from K40 as 17.5e-12 x 31.56e6 = 5.511 mJ/kg/year (=mrem/yr). But if you put 17.5e-12 x 31.56e6 into a calculator, you get 0.0005523 J/kg/yr, which is actually 0.55 mJ/kg/yr, or 5.5 uSv/year. The graph lists 390 uSv/year, off by a factor of 71.
Coincidentally, 71 kg = 156 lbs, or roughly the average human weight, give or take.
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@Clive – To put the “contaminated” food into perspective, drinking only the “contaiminated” milk, for 1 year would equal 1 CT scan, so it still isn’t much to get worked up over:
http://www.maltatoday.com.mt/news/world/japan-detects-abnormal-levels-of-radiation-in-milk-and-spinach
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Great post: at once interesting, informative, and reassuring. It’s impossible to know whether or not to panic without a little perspective.
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As others have already stated; the difference between one-time ionizing radiation exposure (like, for example a chest-x-ray or an international flight) and ingestion/inhalation or otherwise consuming radioactive ash is VAST.
For example, 50 nanograms of Polonium 210 will kill most people outright, if ingested.
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Thank you for this – I was living in Tokyo studying abroad and my home university and parents made me return home, despite the fact that none of us really seemed to understand the situation. Everyone just seems to keep going “radiation OH NOOOOES” and not trying to really comprehend the situation. Thanks for helping foster more understanding.
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@Simon, the Sievert unit takes care of that difference for us already.
50 nanograms of Polonium 210, ingested, causes about 4 Sv of radiation, or four orange squares.
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Make sure we Germans don’t see it. Our local media has shielded us so well from any real information of the actual dosage, it would be a pity to spoil it. /sarc
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Hey, looks like you’re certainly making some waves in the media pond!
http://www.guardian.co.uk/commentisfree/2011/mar/21/pro-nuclear-japan-fukushima
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This represents a great public service in the face of shockingly bad media coverage. Bravo!
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So, one thing I would like to know is the ionizing radiation released by a hydrogen bomb of these sizes:
15 kilotons of tnt equivalent (Little Boy, dropped on Hiroshima)
22 kilotons (Fat Man, dropped on Nagasaki)
300 kt (yield from one of the 12 warheads of the Peacekeeper ICBM)
25 mt (largest nuke ever built by the USA)
50 mt (Largest nuke ever detonated: Tsar Bomba tested by the Soviet Union)
From what I understand, 5% of the energy from a nuclear bomb is released as ionizing radiation (The majority is the blast and heat). So how can we convert tons of TNT to Joules to Sieverts, or something else that would help to add it to the chart?
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Jan, I wasn’t suggesting that hormesis is anything other than a minority opinion. But it is an opinion that is there. The majority opinion, is as I stated: statistically speaking, low doses cannot be definitively associated with either an increase or decrease in cancer risk.
I identified myself as a medical physicist in my first post. I do not consider myself part of the “nuclear industry” as you put it. We do have some nuclear medicine and brachytherapy procedures that involve the use of radioactive materials, so we deal with the NRC. Most of my work involves a linear accelerator. To treat cancer patients. And I have lost friends and family to the disease, so I’m certainly not cavalier about carcinogenic risks.
Sarah, no trouble! 🙂
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Potentially biased like most info on this subject, the authors work for the industry. The Fuk levels suggest the plant is putting out low levels, but data from the plume (i.e., east of the plant) are being withheld by government and industry. The cover up is happening.
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Wow, this chart’s already popped up in a whole bunch of places. I think it’s awesome, I agree that people should try and focus on what has happened more than what might possibly happen. Yes, try to minimise the potential damage and loss of life in case it does, but don’t forget the poor guy sitting in a tent with little food and water and no idea where his family is.
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For those who keep on mentioning radioactive material taken internally…
Dose is Dose — dose from an ingested/inhaled radionuclide is the same as dose from an external source.
The residence time in the body and the effects on target tissues is factored into the dose calculation for an internally deposited nuclide.
e.g.
I saw someone mention that ingestion of 50 ng of Po-210 would kill someone outright.
50 ng of Po-210 is ~225 µCi which will result in an ingestion dose of ~375 rem (3.75 Sv). That is around the LD 50/60 dose for gamma radiation (dose where 50% of those exposed will die in 60 days without medical intervention).
It doesn’t matter if that 3.75 Sv was delivered via ingestion of Po-210 or via external gamma/x-ray radiation — it has the same effect (that is the whole purpose of having radiation units like the Sv and rem). Equivalent dose units like Sv and rem account for the different ways that radiation is deposited.
In reality, the doses assigned based on ingestion/inhalation are 50 year integrated doses and thus don’t have the same impact as an acute external exposure.
To get even more technical; when talking about high doses, it is not really “correct” to refer to equivalent doses since what one is concerned with is immediate harm and not necessarily future cancer risk — the 3.75 Sv equivalent dose from Po-210 ingestion reflects a delivered dose of ~0.1875 Gy (18.75 rad). I would think that it would take much more than 50 ng of Po-210 to be lethal.
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Hello,
Does anyone have the Japanese translation of this chart?
Google doesn’t seem to give me any relevant results.
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Very cool. Thanks for posting this!
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