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Graphic Science: Exposed
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Japan's Fukushima Daiichi nuclear reactor accident has focused new attention on how much ionizing radiation people are exposed to from different sources (see list below). By far the largest source is medical imaging technology (see "Graphic Science: Exposed" in the May 2011 issue). Americans, on average, are exposed to 3.1 millisieverts of radiation a year from natural background factors such as radon gas from the Earth and cosmic rays from the universe. Safety experts recommend the public receive less than one millisievert a year beyond that level, although they do not include medical procedures in that limit because the procedures may bring health benefits. Here's a list of common sources.
Average Radiation Dose to Entire Body (millisieverts)
Natural background (U.S.) per year: 3.1
Airport scanner (backscatter method): 0.0001
Natural gas cooking per year: 0.0004
Arm x-ray: 0.001
Bone density x-ray: 0.001
Highway travel per year: 0.004
Dental x-ray: 0.005
Domestic airline flight (five hours): 0.017
Smoking one pack of cigarettes per day for a year: 0.36
Mammogram: 0.4
Fukushima emergency workers per hour: 1.0
Brain CT scan: 2.0
Thyroid scan (nuclear medicine): 4.8
Brain scan(nuclear medicine): 6.9
Pelvis CT scan: 10
Coronary CT angiography: 16
Astronaut on space station for one year: 72
Sources: National Council on Radiation Protection and Measurements; RadiologyInfo.org
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29 Comments
Add CommentHere's a number that surprised me, in order to get the 500mrem per year they say we get on average, it equates to getting hit 15,000 times per second by a particle or ray of radiation. Every second of your life since the day you were born and since life began on earth 3 billion years ago we have lived in an ocean of radiation. 15,000 times a second ionizing radiation is ripping through your body. Everyone everywhere. Background radiation is always there like the air we breathe. I'm amazed at how people only think radiation comes from nuke plants and x-rays when nothing could be further from the truth. Get on with your life and quite worrying about this one.
Reply | Report Abuse | Link to thisGeek comicist Randall Munroe of xkcd fame drew up a nice chart of doses in the aftermath of the Fukushima accident. http://xkcd.com/radiation/ - it should be fairly accurate but read the disclaimer before taking it as canon.
Reply | Report Abuse | Link to thisOnly an idiot like you would put down a comment like that after the blog took all reasonable effort to outline the effects of our lives.
Reply | Report Abuse | Link to thisAlso youd be dead if you received 500 rems a year. The actual dose is around 5 rems per year if you worked in the nuclear power plant itself.
@ ChasinMT
Reply | Report Abuse | Link to thisIm worrying about your maths, so should everyone especially if youre put in charge of anything in the REAL world.
milli is usually represented by u, m is million. Sp i should say 500 million rems, its way too much.
Reply | Report Abuse | Link to thismilli is usually represented by u, m is million.
Reply | Report Abuse | Link to thisOn the contrary, I think u is micro, m is milli, and M is Mega or million.
"Micro," or one-millionth, is represented by u (or more properly the Greek mu, which is a "u" with a descending tail at the left side). "Milli" is usually just "m." Ten milliSieverts (mS) are 1 REM (radiation equivalent, man), for which the LD50 (half exposed short-term will die without treatment) is 400 REM, or 4000 mS, or 4,000,000 microSievert. According to this chart, the Fukushima Daiichi workers on-site presently are receiving more than twice that dose annually, or 8766 mS (867 REM).
Reply | Report Abuse | Link to thisAs to "getting on with our lives" because we "live in a sea of radiation," I was taken by the preface to this comment, that the reader was "surprised to recently learn" this fact. Keep reading. There are orders of magnitude between background doses and acute doses, and the even more insidious man-made jumps in background. Read especially UN reports on Belarus childhood thyroid cancer after 1986, the nature and quantity of birth defects in Ukraine, the rise in skin cancer in Southern Argentina, and the accounts of the suffering of witnesses in Pripyat who were not warned for three days about the changes in the "sea of radiation" they were swimming in.
It's likely that a unit 3 SFP prompt criticality released tons of transuranic radionuclides at Fukushima on March 14. On March 16, the US military (having access to Xenon isotope ratios in the plume from the detonation in unit 3) told civilians in the area to move 50 miles away and started pulling ships from South Japan harbors and going to sea.
It's been common practice since the Manhattan Project to sample air for fission products to back-calculate the source. This data has not been released to the public.
It is my humble opinion that government and industry special interests are downplaying the nature of radiation releases from the still-ongoing crisis at the Fukushima Daiichi site. Stock prices, a fragile economy, a country devastated by two other natural disasters all need protecting. I don't believe that bad science or science that ignores true risk or fudges or withholds numbers is a good way to perform this service.
I would rather those who know and understand the nature of Fukushima radiation releases should provide that data. Being a knowledgeable publis, we can work together to protect society, Japan, our food supply and each other. Ignorance, complacency and risk minimization are some of the causes for accidents at Chornobyl (Ukrainian spelling) and Fukushima Daiichi in the first place.
If the tone of this SciAM article was intended to promote calm, it did the opposite for me.
Couple of errors in my post that I missed. Sorry about that. One's a math error. The other could be funny. Happy hunting.
Reply | Report Abuse | Link to thisIt's the 'cumulative' doses and its residual effects that we have to worry about as we increase the amount of radiation we are already exposed to. Most of those things listed can be done in a short period of time, within the year. Add them up.
Reply | Report Abuse | Link to this"There is no safe level of radiation". How often have we heard that one? Yet there are many places in the US that have twice or more the radiation of others. Why haven't we haven't seen studies showing what affect that difference makes? Even a study based on deaths from the kinds of cancer higher radiation causes on the populations of Louisiana or Florida vs Colorado or Wyoming? My guess is that it is in no one's economic interest to publish such a study. But it does make me wonder.
Reply | Report Abuse | Link to thisThe linear hypothesis for low-level radiation exposure has been pretty well established. Cumulative-dose exposure is never good, but what happens at low dose levels is lost in the noise. No epidemiological studies that distinguish between a few microSieverts here or there would show much, since the effects are indistinguishable from other environmental inputs. Twice infinitesimal is two times infinitesimal. But the economics go the other way, actually.
Reply | Report Abuse | Link to thisThe threshold hypothesis that stated a plateau existed below which no harm was done has been fairly well disproven with biological studies. We all live in a sea of radiation and some of that radiation destroys computer chips from time to time. This is a common topic in electronic engineering when something fails for no reason after thorough investigation. Cosmic rays do from time to time knock out a memory chip or CPU. They also from time to time knock out the DNA of a growing cell and cause it to go cancerous. For decades the nuclear power industry attempted to say that this lower threshold was harmless, but in fact any exposure does increase risk.
It doesn't mean that we can't build plants. It simply means we need to recognize that carelessness in decision making isn't justified by the science. We need to know up front that we're accepting the risk, not distort the science to show there isn't any.
I'm willing to accept that the linear hypothesis is true and proceed on those grounds, that protection from undue routine releases needs to be built into future systems. Steam, water and waste product disposal along with LOCA meltdown containment need to be handled in such a manner that increased exposure is minimized, knowing that it's a risk, not pretending that it isn't.
There is a cumulative dose calculator here: http://www.new.ans.org/pi/resources/dosechart/.
Reply | Report Abuse | Link to thisIn a max year my dose is 1000 mS, and I'm aware of background sources yet still use yellow bathtubs, eat Brazil nuts and fly internationally. I'm not a catastrophe monger and support judicious use of nuclear power like CANDU systems, illegal in the US due to a positive void coefficient.
I object to withholding dose rate data to protect shareholder value and government reputations. Long after Soviet officials assured us Chornobyl #4 was intact, the Soviet senior director of nuclear engineering calculated the core explosion generated on-site dose rates of 20,000 Roentgens per hour, over 2 million mS or 238,000 REM, about 600 times LD50.
I'm not suggesting Fukushima releases are on that scale, but to date we don't know dose rates or radionuclide composition from the massive explosion in unit 3's fuel pool, water leaks from unit 2's torus broken during an internal explosion, and worst of all we don't know have detailed, time-based dose rate and radionuclide data for deposition on the northeast Japanese countryside despite anecdotal evidence of widespread distribution of fission products, or fish exposure despite direct release of contaminated water into the Pacific Ocean.
All relevant dose rate information should be gathered and made public so we can plan our future use of this technology as informed citizens. Today it requires an FOIA suit to achieve this, and there is great uncertainty about monitor distribution and data acquisition. It is not clear if decisions may have been made to avoid gathering data.
I believe people will be surprised by high dose rates throughout this accident and by severe damage to reactor cores, containments and fuel at Fukushima -- if the information is ever released.
Extreme conditions for a week were handled by the Fukushima 50 at great sacrifice, and they made the right moves in the right order at the right time with little support from TEPCO or their government. That's a story I want to hear when the crisis is over and they are allowed to tell it.
All of the chatter about background radiation is in my view an attempt to keep selling nuclear power by minimizing upward excursions as if they akin to breaking your diet with an extra helping of French fries, ignoring simple facts like dose rates for Chornobyl firemen being 17 billion times background.
At some point it is disingenuous to show annual or one-time dose rates for everything but the Fukushima workers, whose exposure is shown as an hourly dose.
It is not the amount and accumulation of radiation received that causes cancer. Cancer is caused by one high-speed radiation particle colliding and destroying the division centre in one cell. Once the area for division cessation is destroyed the cell will multiply continuously and cause cancer. Even though your probability of cancer increases with the amount and duration of radiation received there is still a possibility with a short, low dosage. It is a matter of hitting one cell in the correct location at the proper time. In my opinion there is no safe dosage of radiation. It all has to do with probability and chance. You can win the lottery with one ticket but lose with 10,000 tickets.
Reply | Report Abuse | Link to thisThank you for your informed comments.
Reply | Report Abuse | Link to thisIt is so difficult to get a rational public debate on the subject of nuclear power. The complexity of the subject tends to aid radical anti nuclear views in my opinion but secrecy about bad outcomes will also end up having a negative outcome so far as the industry is concerned.
Fortunately there have been few bad outcomes. Those that have occurred could have been foreseen & prevented although in Japans case the circumstances were certainly extreme. Lessons will be learned. When an airline crash occurs, the investigation could be devastating for the aircraft manufacturer yet the public is reassured by the knowledge that the full details will be released & the end result is not that we cease flying but that the system is improved. Hopefully this procedure will be followed with this nuclear system failure.
The difficulty will remain of explaining the pros & cons to the public against the hysterical claims of some. As part of the understanding, the cost in terms of health & environmental damage other power generation systems or lack of adequate power impose must also be considered. Primitive conditions persisting in much of the world through lack of adequate moderate cost power have an enormous human health & wellbeing consequence for example.
Actually, a lowercase 'm' is the prefix for milli, as in millimeter (mm). An uppercase 'M' is the prefix for million or Mega, as in MW. The prefix 'u' that you refer to, I think you might be thinking of the greek letter mu, which looks like a 'u'. The prefix mu refers to a micron, meaning one-millionth (10^-6).
Reply | Report Abuse | Link to thisIt is pointless to inform the public of any imminent danger. The tsunami warning system was good for a 10 minute warning on a wave traveling 500 mph, which may have saved one life, if that. The only chance the Japanese had to escape was by motorized transport (and it would have had to be a rocket powered one with wings), but the streets would have been immobilized by traffic chaos anyway. Lesson to be learned: Require carbon fiber surfboards with seat belts for every resident inside a tsunami-prone area. (double and triple-wide available for California).
Reply | Report Abuse | Link to thisRadiation figures are pointless since the governments, like all good parents, intend to lie about the true danger anyway. And why shouldn't they? Fukushima prefecture has a population of over 2.3 million. If the situation was hypothetically as dangerous as Chernobyl, where would you put those 2.3 million radiation refugees? And what if it had been Tokyo, with ten times that population? If you knew for certain that Somalia was headed for a massive drought, would you advise them to skip the spring planting, since a failed crop would bankrupt and result in the death of a lot more people in the chain of commerce than would have died from just indigency? Any forewarning leads to a violent scramble for cash, which leaves the women, children and other innocents at a physical disadvantage. The Soviet break-up was a perfect example of survival of the most brutal, criminal and exploitive - the exact opposite of what human civilization is trying to achieve.
Reply | Report Abuse | Link to thisAt last an accurate definition of units.
Reply | Report Abuse | Link to thisHopefully some of those above will learn what's what in the matter of units
Fukushima Prefecture has a population of 2.3 million. If you knew that the radiation levels exceeded lethal levels, would you tell anyone? If you knew that a once-in-300-year drought was headed for Russia, would you tell the farmers to skip spring planting to conserve their cash so that they could survive until the following year? If you knew that record flooding would kill 12 million some people in Pakistan, where would you suggest that they go, eat, sleep, wash?
Reply | Report Abuse | Link to thisGarbage. Of course I would. You may lie to your children about serious matter I do not. Exactly which near deities would be in the know? You included no doubt.
Reply | Report Abuse | Link to thisWhat I hear in the US is that we are checking nuke sites after Japan's tragedy. Europeans aren't just checking, they are testing. That sounds like a significant difference to me. Also, each US check is merely comparing each site to an "expected" earthquake magnitude. Nuclear failures seem to be cluttered around just the opposite, -the unexpected.
Reply | Report Abuse | Link to thisMy understanding is that earthquakes cannot be adequately predicted, much less reliably. So to build a nuke plant to sustain some esoteric prediction seems like a recipe for disaster at some time, at some location. If the plants, which are only built for 20 years would be decommissioned and replaced by clean alternatives, we could discuss if this is a reasonable risk to take. But nuke operating licenses are renewed, in some cases repeatedly, and the odds keep stacking up against us.
In addition, the pace at which we are adding alternative energy production does not even cover the annual increase in energy demand, much less replace existing nuke sites. We really should be talking about recommitting half the military budget from current priorities to expanding all types of public infrastructure and growing alternative energy production, if we want true national security.
Our nation's security sustainability does not depend on military operations; History teaches us it depends on economic sustainability and infrastructure. Just consider Japan's ability to recover from multiple meltdowns. (and yes, economic sustainability depends on education) :)
Funny they mention Smoking but not more mundane things like.
Reply | Report Abuse | Link to thisCell phones
Microwave ovens
Computers
High tension power lines
Tanning beds
I guess its safe to be self absorbed and or superficial.
Just don't light one up.
Japan will rebuild nuclear power stations because despite the recent disaster, base load alternative energy is a pipe dream & thousands die every year from pollution & mine accidents associated with coal fired power stations. What happens after an airline disaster? Do we cease to fly or make the system safer? Many more people have died from plane crashes than from nuclear power generation. What about cars. Last I heard three million deaths per year plus many times more with devastating injuries. The paranoia about nuclear defies logic.
Reply | Report Abuse | Link to thisBonzo666: The article was about Ionizing radiation. Most of the sources you cited emit electromagnetic radiation of far to low an energy level to ionize anything. Tanning beds can, but the penetration level is relatively short, so only the skin is effected. This can indeed cause cancer, but the radiation levels required are much higher than that of deeply penetrating radiation, so I think it is correct to leave this out of such a short article.
Reply | Report Abuse | Link to thisOK, I posted first, maybe I'll post last.
Reply | Report Abuse | Link to thisFirst Off, 500mrem is millirem, or 5 Millisieverts for those of you challenged by the simple spelling of Google. It depends on who you believe as far as whether we get 350mrem/yr or 620mrem/yr you'll find these numbers everywhere. I chose to split the difference.
This does not obviate the fact that you get hit 15,000 times per second by some form of ionizing radiation. The mrem & sieverts are gobilly gook terms trying to put some simple term to the 470 trillion of bits of radiation that rip through you annually.
My main point is, you've been dealing with this radiation biologically your whole life, and everything’s life has dealt with it since time began. It is a natural thing. I'm not saying you should run out and get over-exposed to it, cause too much of anything is bad for us....how many people drown in water each year? Yet we don't really wanna freak out over that stuff. Keep sensationalizing if you want. You sound very silly to those who understand better.
I do work in nuclear plants, and 500 millirem is a good number. Look for a new web site called Google, it's great, you could start with "mrem" for a search term, then find "15,000 radiation second". You'll see that I speak the truth, and that you, as well as 99.9999% of the sheep on this planet who chose not to think for themselves, are duped into freaking out by a lame media machine that apparently thrives on the fact that you like to be afraid of stuff. Knowledge will set you free.
Reply | Report Abuse | Link to thisBTW, very, very few people in nuclear power in this country get 5rem a year occupationally, I'd guess the average to be around 1.5 rem. Again if you Google it, you'll see there are folks in India and Iran that get 5rem or more from background radiation every year, all their statistically unaffected lives.
One of the "benefits" of the accident at the Fukushima nuclear power plant is that the media started to look at the levels of radiation to which public is exposed to continuously. A decade ago it was not possible to get such facts published in the mainstream media. Radiation dose to public from nuclear power plants was getting exaggerated attention.
Reply | Report Abuse | Link to thisMany members of the public may not know that millions of people are getting exposed continuously to natural background radiation (external gamma sources or radon decay products as internal sources) at levels much more than those at which people are evacuated from their dwellings near Fukushima.
That said we must do every thing possible to reduce exposures to public from all sources of radiation wherever possible. Ionizing radiation is truly secular. Whether the source is natural or man-made it interacts with living tissues the same way. There are ample reasons to control exposures to radiation to values As Low As reasonably Achievable(ALARA) without losing benefits, if any, from such exposures.
For a discussion on what is a safe dose of radiation please see:
You may call it paranoia if you wish. Radiation is odorless, tasteless, colorless, and to a large extent, exposure is painless. When I get in a car or airplane, I see and am aware of my surroundings and I have an appreciation of the immediate risks. I also have some control and some influence on those risks.
Reply | Report Abuse | Link to thisIf you get gov't subsidies and build a nuke plant next to me (you can't build one without subsidies), you can release lethal radiation into my private home in the light of day; and I might never know, even after radiation sickness is diagnosed and progresses.
Do you see how invasive this potential is in coming into my own home? How stealth it is? Or how much it involves me to trust you or someone else that does not agree with me and who also has a profit motive directly opposed to my safety, well being, and opposed to my real time knowledge of events such as TMI? There is no safety around nuke plants, if you understand the precepts in this paragraph. Do you want to make all nuke plants non-profit in order to build more of them? I could discuss that alternative.
Radiation doses under 100 mSv and longer term doses under some thousand mSv/year are not dangerous.
Reply | Report Abuse | Link to thisSome radiation exposure can even be good for your health by stimulating the cellular repair machinery - which has existed in every cell's genome for some 1-4 billion years *)
There are huge variations in natural background radiation levels. For instance here in Scandinavia ( and in Canada, Brazil, Iran,..) we have granitic bedrock, which has on average about 30gr/m3 Uranium. When U decays, it releases also Radon, which is easily released to atmospere- and also to our houses. There are houses with 10- 10000 times more Radon in the air than the normal level 400 Bq/m3 !
And still we can't see any rise in cancer incidence levels?
Also Chernobyl fallout is distributes unevenly- no corresponding variations in cancer incidence is seen, not even near Chernobyl *)
Soviet Cold War nuckear tests in nearby Novaja Zemlja brought a lot of Pu and Sr, Cs isotopes here. Nothing is seen in cancer statistics after 50 years.
Small sub-micrometer sized particles from coal, oil, wood,natural gas, biomassa burning,.. are much more dangerous- millions of people die every year because of these small particles ...
See more
*) www.ncbi.nlm.nih.gov/pmc/articles/PMC2592992/
www.ncbi.nlm.nih.gov/sites/ppmc/articles/PMC2889503/
www.stuk.fi/en_GB/