While doing some research on Thorium, I came across this interesting little fact that I wasn’t familiar with, so I thought I’d pass it along. Many people fear radiation, sometimes the fear is irrational, based on the erroneous concept that we live in a “radiation free lifestyle”. I’ll never forget one time when I showed my geiger counter to a neighbor who was shocked when it started clicking. She was horrified to learn that cosmic rays were in fact zipping right through her body right that very second. I didn’t have the heart to tell her about neutrinos.
But, along the same lines, this little factoid might drive some people “bananas” when they read it. But, it illustrates a fact of life: radiation is everywhere.
A banana equivalent dose is a concept occasionally used by nuclear power proponents[1][2] to place in scale the dangers of radiation by comparing exposures to the radiation generated by a common banana.
Many foods are naturally radioactive, and bananas are particularly so, due to the radioactive potassium-40 they contain. The banana equivalent dose is the radiation exposure received by eating a single banana. Radiation leaks from nuclear plants are often measured in extraordinarily small units (the picocurie, a millionth of a millionth of a curie, is typical). By comparing the exposure from these events to a banana equivalent dose, a more intuitive assessment of the actual risk can sometimes be obtained.
The average radiologic profile of bananas is 3520 picocuries per kg, or roughly 520 picocuries per 150g banana.[3] The equivalent dose for 365 bananas (one per day for a year) is 3.6 millirems (36 μSv).
Bananas are radioactive enough to regularly cause false alarms on radiation sensors used to detect possible illegal smuggling of nuclear material at US ports.[4]
Another way to consider the concept is by comparing the risk from radiation-induced cancer to that from cancer from other sources. For instance, a radiation exposure of 10 mrems (10,000,000,000 picorems) increases your risk of death by about one in one million—the same risk as eating 40 tablespoons of peanut butter, or of smoking 1.4 cigarettes.[5]
After the Three Mile Island nuclear accident, the NRC detected radioactive iodine in local milk at levels of 20 picocuries/liter,[6] a dose much less than one would receive from ingesting a single banana. Thus a 12 fl oz glass of the slightly radioactive milk would have about 1/75th BED (banana equivalent dose).
Nearly all foods are slightly radioactive. All food sources combined expose a person to around 40 millirems per year on average, or more than 10% of the total dose from all natural and man-made sources.[7]
Some other foods that have above-average levels are potatoes, kidney beans, nuts, and sunflower seeds.[8] Among the most naturally radioactive food known are brazil nuts, with activity levels that can exceed 12,000 picocuries per kg.[9][10]
It has been suggested[11] that since the body homeostatically regulates the amount of potassium it contains, bananas do not cause a higher dose. However, the body takes time to remove excess potassium, time during which a dose is accumulating. In fact, the biological half-life of potassium is longer than it is for tritium,[12][13] a radioactive material sometimes leaked or intentionally vented in small quantities by nuclear plants. Also, bananas cause radiation exposure even when not ingested; for instance, standing next to a crate of bananas causes a measurable dose. Finally, the banana equivalent dose concept is about the prevalence of radiation sources in our food and environment, not about bananas specifically. Some foods (brazil nuts for example) are radioactive because of radium or other isotopes that the body does not keep under homeostatic regulation.[14]
- ^ http://www.ehs.unr.edu/ehs/LinkClick.aspx?fileticket=EgZI00myQRM%3D&tabid=62&mid=615
- ^ Weston, Luke. (2007-07-25) banana dose « Physical Insights. Enochthered.wordpress.com. Retrieved on 2010-10-19.
- ^ CRC Handbook on Radiation Measurement and Protection, Vol 1 p. 620 Table A.3.7.12, CRC Press, 1978
- ^ Issue Brief: Radiological and Nuclear Detection Devices. Nti.org. Retrieved on 2010-10-19.
- ^ Radiation and Risk. Physics.isu.edu. Retrieved on 2010-10-19.
- ^ A Brief Review of the Accident at Three Mile Island
- ^ Radiation. Risks and Realities, US Environmental Protection Agency
- ^ [1][dead link]
- ^ Brazil Nuts. Orau.org. Retrieved on 2010-10-19.
- ^ Natural Radioactivity. Physics.isu.edu. Retrieved on 2010-10-19.
- ^ Bananas are radioactive—But they aren’t a good way to explain radiation exposure. Boing Boing. Retrieved on 2010-10-19.
- ^ Rahola, T; Suomela, M (1975). “On biological half-life of potassium in man”. Annals of clinical research 7 (2): 62–5. PMID 1181976.
- ^ Environmental Health-Risk Assessment for Tritium Releases at the NTLF at LBNL: Chapter 2. Lbl.gov. Retrieved on 2010-10-19.
- ^ Brazil Nuts. Orau.org. Retrieved on 2010-10-19.
G. Karst says:
Financial Post
Lawrence Solomon: Radiation’s benefits
So Lawrence Solomon discovers hormesis. What an enlightenment! Hormesis has been widely discussed in the nuclear industry for years. There is even a publication, the BELLE Newsletter, about hormetic effects including low levels of radiation. It has been around for about 20 years if I recollect rightly. Like Lawrence didn’t know it! He also knew that the very organizations and regulatory agencies responsible for the modern radiation protection framework, including the ICRP stated clearly that there was no way of knowing whether human response to radiation was linear no threshold or if, in fact, a threshold for the onset of detriment existed. Rethinking indeed!
He and Energy Probe used LNT to beat up on the nuclear in Canada just to destroy the indsutry. Unlike reputable RP specialists his was more than a rational belief in LNT. He was happy to ally himself indiscriminantly with its most alarmist element including the likes of Helen Caldicott who attributes virtually every affliction and misfortune of mankind to the nuclear industry. Note any similarities to AGW alarmism?
Then a terrible thing happened. The Ontario government decided to build windmills all over the landscape and phase out coal. This necessarily will means that energy costs will soar either through higher energy costs or subsidies recouped through taxation. This is what your duplicity has bought us Lawrence.
Don’t believe Big Green’s epiphany about nuclear power. Don’t believe Lawrence’s either.
Do you have a reputable website to link to, or just wikipedia and unsigned/un-accounted story pages?
Radon gas is a decay product of both radioactive uranium and thorium which occur naturally in the soil. The outdoor radiation monitors that surround nuclear facilities regularly go off after a heavy rain because the radon in the air washes out and accumulates at ground level. Makes for some fun with the inexperienced health physics guys the first time it happens to them.
If anyone is interested in deeper aspects of radiation and its health effects, I wrote this background paper for NWMO.ca. At the front of it are primers on radiation and radioactive waste, followed by health aspects, followed by a detailed appended list of studies. The appendix should be interesting to most intelligent people.
http://www.nwmo.ca/3.2
Well, that explains something about banana-benders (Queenslanders), anyway!
It is also worth noting that certain rocks are far more radioactive than others. I recall discovering that granite is a particular offender in the this area. As it is formed lower down (under greater pressure, IIRC), the heavier elements such as Uranium tend to collect within this layer. The result is a greater amount of radiation.
Not too important, but often people make nice granite fireplaces, bathrooms or kitchens, thus increasing their exposure to radiation. Some cities are largely built of granite, too. I seem to recall Glasgow is one, and the background radiation in such cities is about twice ‘normal’.
Yes, this radiation is everywhere, and obviously entirely natural. We are lucky we are shielded from so much of it from the sun, or life would be very, very strange on Earth, if it made it at all. Probably odder than Queensland, even….
Very interesting.
Even New Scientist (03 August 2010: Who’s afraid of radiation?) is reporting that radiation safety limits may be 10 times too conservative.
“Our attitude to ionising radiation is irrational, and easing safety limits would do far more good than harm, says Wade Allison”
http://www.newscientist.com/article/mg20727715.800-whos-afraid-of-radiation.html (paywall).
By the way, anyone with a phobia against Fiesta ware, can ship it all to me. Please! I have one very interesting collection of radioactive things and proud of it.
Alchemy says:
February 16, 2011 at 12:42 pm
That puts it all in perspective, it’s true!
John K. Sutherland,
http://unitednuclear.com used to sell Fiesta ware. But that was a few years ago. You can still buy uranium though. And meteorites!
If I were to frequent anti-Nuke demonstrations, I’ve fantasized about handing out organic bananas to the participants and explain the joke later.
Thanks for all the details, I hadn’t read the numbers before. I forget if I had heard of the BED, certainly worth remembering now.
14C is also prevalent in lotsa stuff (like any plant grown outside). I think the potassium in the bananas is a lot stronger, but it worthwhile pointing out that to reduce one’s 14C content, one should eat food produced from CO2 derived from coal, oil, and natural gas combustion. Not wood!
IIRC, some of the concern from at home exposure to radon came from a nuclear power plant worker who triggered the alarm going _into_ work one day.
Also IIRC, much of the risk of radon came from studies of uranium miners. Many of them smoked, and radon daughters attached to the dust they inhaled and that lodged in their lungs giving them a radiation dose from the post-radon decay line. Wikipedia has some very nice decay chain graphics, see http://en.wikipedia.org/wiki/Radon . Once radon decays, it emit two more alphas and betas very quickly, hangs out at 210 Pb for a while (22.3 year half life) and that emits an alpha and two betas before stopping for good at 206Pb.
Re: Jeremy, you mean like the fully signed and peer reviewed global warming sites???
I’ll leave it up to you to peruse the many Google/Yahoo pages and let you decide which ones have the most logic….
Having worked for DOD for decades, I’m just a bit familiar with Government practices in let’s say similar areas and as a result I tend to go with the “unsigned” “unaccounted for” sites over the “certified” government ones when they make sense. But, hey it’s your choice.
It would be better to avoid a geologically active area like a trench. A practical solution was floated around 15 or so years ago that would have involved placing waste into stainless steel canisters and dumping them into thick oceanic mud a few hundred miles NW of Hawaii. The absence of oxygen at those depths would inhibit rusting. The greens pressured Clinton to sign a treaty banning such dumping–not that he needed much pressuring.
I used to work in a UK nuclear power station as an industrial chemist, although we shared an office with Health Physics so I got a “dose” of that too.
One day a very senior executive called a press conference to talk about nuclear power – a “hot” issue at the time. Prior to the start the Press helped themselves to bowls of chocolate Brazils that were positioned around the room.
Once the conference was underway, the big man started talking about nuclear waste and especially the long term storage of low level waste. He compared the radiation levels with those in the chocolate brazils the press had been eating – our Low Level Wate is far less radioactive than the brazil nuts you have been enjoying. Not a single further brazil nut was eaten; several members of the Press tried to regurgitate the brazils they had already eaten and, I am told, the meeting ended in a degree of chaos.
He made his point but the members of the Press were far from happy that they had been poisoned by all this radioactivity!
I have a sizable collection of Vaseline glassware, sometimes called Depression glass which contain uranium. My oldest peice, an 1880 vase, contains between 5 and 10% uranium oxide. I wonder how many bananas worth of radiation I have in my display cabinet?
Renaming the yield of the Hiroshima bomb to a 13 kilobanana detonation severely reduces its scare factor. Threatening to drop a 20 megabanana device on someone just doesn’t inspire much fear. So much for our strategic banana deterrent.
You should promote these physics lectures for non-physics students at Berkeley. The entire series should be mandatory for anyone with a brain, here are radioactivity I + II, and nukes:
http://www.youtube.com/watch?v=EHwpqszz-Rc
There is also a lecture wrapping up all the subjects in one go, from the Physics for future president series (and a book by that title)
There is substantial evidence that low level radiation has less of an effect than would be expected. The term “radiation hormesis” has been used and attempts have been made to explain how low level radiation may, perhaps, stimulate the immune system.
There is a review dated 2002:
Review: Cancer Risk from Low Level Radiation
http://www.phyast.pitt.edu/~blc/Cancer_risk.pdf
The review concludes that assuming risk is linear down with radiation dose down to zero radiation/zero ” … grossly overestimates the risk from low level radiation.”
Despite this, the National Radiation Protection Board and other organisations still assume that all radiation is bad – the linear, no threshold, model.
@Gras Albert says:
February 16, 2011 at 10:10 am
Next time you are outside on a clear night look up…
Nuclear energy is the single most common naturally occurring phenomena in our universe
—————-
Watch it. You’ll get the electric universe nuts to come out from under their rocks.
JER0ME said: February 16, 2011 at 2:16 pm
“It is also worth noting that certain rocks are far more radioactive than others. I recall discovering that granite is a particular offender in the this area. As it is formed lower down (under greater pressure, IIRC), the heavier elements such as Uranium tend to collect within this layer. The result is a greater amount of radiation.”
Correct result, wrong mechanism – try “granite” in Wiki as a start.
“Some cities are largely built of granite, too. I seem to recall Glasgow is one, and the background radiation in such cities is about twice ‘normal’.”
Edinburgh is the normal example of a granite city – built on and with granite. Aberdeen is the generally quoted twice ‘normal’ example – again a granite city. All in Scotland, of course.
Alan (Currently a geology student from the UK)
“Threatening to drop a 20 megabanana device on someone just doesn’t inspire much fear. So much for our strategic banana deterrent.”
Somebody getting their “just desserts” this “Sundae”? (Sorry!)
Ah, but not the DOE? I’ve also worked with Gov’t for a long while now. I’m shocking myself to say this but there there are some gov’t agencies that are historically run very well, with nothing left to chance. DOE is one of them. BTW, name dropping will get you nowhere here.
You have unsuccessfully deflected the question, btw. Do you have any reputable references? Wikipedia is not. Unsigned websites are not.
ABC News just told me how the esteemed Center for Science in the Public Interest (CSPI), as announced by the esteemed Executive Director Michael Jacobson, is informing the public about the cancer risk posed by “caramel coloring” as found in sodas:
http://abcnews.go.com/Health/cspi-caramel-coloring-cola-cancer-soft-drink-industry/story?id=12932008
One of the chemicals found, 4-MEI, has made the infamous list: “Chemicals known to the State of California to cause cancer.”
Death by bananas, or death by soda… Decisions, decisions…
Meanwhile I’m waiting for Kalifornia to get around to banning electronics and pretty much all electrical devices, since they are known for producing ozone which is a well known potent cancer-causing chemical.
Long Term Ozone Exposure Raises The Risk Of Dying From Lung Disease
http://www.medicalnewstoday.com/articles/142097.php
Dana Reeve, wife of Christopher Reeve (Superman), who was athletic and never smoked, died of lung cancer. Her husband was surrounded by electrical devices after his accident, leading to Dana being exposed to increased levels of ozone from electrical devices for about a decade. See? Proof!
Someone alert the CSPI of the urgent need to immediately ban these producers of a known carcinogen. Think of the children!
Has anyone googled “marijuana” and “radioactivity”? They blame it on the fertilizer, which you can buy at the local supermarket. Just don’t eat it (the fertilizer).
@jojo
“Antony, why dont you talk about Chernoby?”
What’s to talk about? An inferior nuclear power plant of old crap communist design and run by a bunch of communist drunkards being drunk on duty . . . accident waiting to happen.
“Care to talk about and show photos of the children being born deformed?”
You mean from the ones who rather not pay for land and so disregard safety and go to to live on and of the waste land just because it is cheaper ‘an dirt cheap? Blame those idiots will ya.
“how long will the site remain radioactive?”
For ever since it was radioactive before they put a crappy designed crappy run nuclear power plant on the site in the first place.
Of course would the accident have happened if the world since the 70’s hadn’t stopped R&D, and furthering, of everything civilian nuclear due to crazed hippie paranoia fear?
re post by: Jeremy says: February 16, 2011 at 4:05 pm
While there are a lot of good people in the DOE, some good aspects, and pockets here and there of well run groups – generally in comparison to decently run nuclear power utilities and decently run private companies I’d hardly say that DOE is anything close well run, let alone very well run. DOE suffers tremendously from the same problems most of the government does – an inability to get rid of really bad employees because of unionization (made worse than even in the private sector, because even professional ranks are unionized in the gov.), inability to police their own facilities/programs effectively or correct problems with any speed, horrendous waste of money, time, and resources, and so on. Well run surely isn’t a term I’d apply, unfortunately.