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.
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Well no wonder I glow after eating a loaf of my wifes banana bread. And here I thought I was just fat and happy. LOL!
Very bad joke:
More people have died in Kennedy cars then died from radiation at three mile island….
I love it when nuclear physics and understandable analogies intersect.
Hahaha good stuff!
People are always amazed when I tell them that a nuclear power plant gets shut down when it leaks radiation equivalent to the amount a coal fired power plant puts out continuously…it puts the danger of nuclear in some much needed perspective…
This was a plot element on “NCIS LA” last night, and I snickered.
Color me chastised. 8^(
Thank goodness that the Australian bannana crop was wiped out by the recent cyclone (not really), humanity has been saved from lots of radiation. No if they could only do something about their AGW folks.
Radiation hormesis is a well known effect and the benefits of living in a high background environment are well known. See for example about Ramsar in Iran (where the convention was signed) http://www.iaea.org/Publications/Magazines/Bulletin/Bull332/33205143638.pdf and http://www.probeinternational.org/Ramsar.pdf
don’t tell Michelle Obama, she’ll ban bananas …
Very apeeling.
Interesting timing of this article. You wrote “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]”
Last night, on “NCIS: Los Angeles”, the bad guys stole a nuclear weapon, and the NCIS crew was speculating that they may use a truck full of bananas to transport the weapon, thus making detection of the weapon harder. The thought was that the truck would be pulled over because it tripped the radiation sensors that had been deployed to look for the bomb, then the authorities would see all the bananas and let the truck go, not realizing there was a nuclear weapon underneath.
One excellent way of sequestering banana radiation is by putting sliced banana into a mixture of flour, sugar, water and oil and subjecting the blend to high heat for a short period of time. When made in large batches and put into kilogram-size wrapped parcels they can be shipped to many individuals for safe storage, reducing the risk of terrorist’s acquisition of large quantities of the resource.
Many studies have been done on this concept, and early studies resulted in the discovery of a replacement for expensive sandbags or concrete blocks for construction, affectionately called “fruitcake”. (unlike its impractical cousin “yellowcake”, “fruitcake” has an unlimited shelf life)
As a nuclear engineer who formerly worked for Uncle Sam and now works in the commercial nuclear industry, it is frustrating to hear the same “crowd” who is so slow to skepticism in all other relams jump off the skeptical cliff about nuclear power. We continuously present facts that show the power source is safe when operated properly only to be rebutted by “What about Three Mile Island or Chernobyl?” Bad joke above, but accurate point about the late Sen Kennedy’s auto woes vs the nuclear power industry.
The banana analogy, and the BED as a more specific measure, is a great way to get the point across. Discussing alphas, betas, and gammas, OH MY! just makes the uneducated eyes roll back. So thanks Anthony for spreading the word a little more.
Finally, if you are impressed by the dose from a banana, DO NOT eat off of old orange FiestaWare ceramic plates. The pigment (at least at one time) was made with some higher-than-natural percentage of uranium oxide. Those plates can easily alarm a geiger counter that has no issues with the background field. Not a huge deal in the scheme of things, but will certainly open the eyes of someone who doesn’t understand radiation is everywhere.
I will never again eat peanut butter toast and a banana before flying. You get everything searched. Trust me. I know.
At an airport, not that long ago…
After a fruitless trip through my luggage (pun intended), a pat down down and whatever she could think of the frustrated security agent looked up and said “Did you eat breakfast?” “Uh-huh” I said. She looked me straight in the eye and said “Peanut butter and bananas?.. Or are you smuggling?” I replied: “Peanut butter toast and a banana.” She told me to “Get lost!” and yelled her supervisor over and gave him a lecture about “crappy detectors”.
True. I swear!
The latest one was “Did you polish this jewelry while you were gone?” at the end of the search. Another sin apparently… That one set off the chemical sniffers and unfortunately it was quiet and they were bored so I got about 15 minutes worth of pat down and bags checking…
Along the lines of advancing nuclear power, I’ve been thinking about a potential change.
A fair chunk of getting permission for a nuclear site resides in the extensive geological survey and environmental impact assessment. And the budget for the lawsuits involving every detail overlooked in those studies.
Put the actual core building on a barge. Put the ’emergency shutdown’ cooling on the barge as well.
The mammoth cooling towers are for the outer loop. And thus not part of ’emergency cooling’. Nor are they dealing with radiologically active material.
The major threat to a nuclear site – earthquakes – is pretty much relegated to a side issue at that point. Yes, it can damage the stuff that isn’t on the barge. But it essentially can not cause a radiological leak. The fact that the actual core ends up with a sizable moat and is thus also more difficult for a truck bomb or protestor to even reach is a bonus.
Your neighbour should move to Cornwall (UK).
http://www.cornwall.gov.uk/default.aspx?page=17397
Another interesting fact…
A person living within 50 miles of a nuclear plant receives less radiation from it in a year than you get from eating one banana.
from a highly recommended read
Power to Save the World: The Truth About Nuclear Energy by Gwyneth Cravens
Hey Mister tally-man, tally me bananas.
Geiger counter click and me wan’ go home.
They actually mentioned this last night on the TV show “NCIS Los Angeles.” It was suggested that someone smuggling a nuclear weapon could hide it in a truck full of bananas.
For God’s sake don’t let Michelle Obama see this!
The voice of Kraftwerk’s “Radioactivity – is in the air for you and me” suddenly appeared in my head. http://www.youtube.com/watch?v=kXD6Gtinvbc
An important note to remember though:
Not all radiation is equivalent.
Potassium is a beta- (electron) emitter.
Cobalt 60, will give off a b- and/or gamma.
Radon, found in bricks, will give off an alpha (helium) particle.
As for protection, clothing will stop alpha, unless you ingest it, your dead skin layer will stop beta.
gamma and neutron are considered whole body doses, because it will interact anywhere in the body.
Alphas and neutrons will cause more damage than betas or gammas.
After an element experiences decay, it loses mass and usually becomes another element.
Mr. Watts you have something against scientific notation.
REPLY: Huh? Lots of WUWT articles contain scientific notation. What’s your gripe here? – Anthony
“Low-dose radiation has been shown to enhance biological responses for immune systems, enzymatic repair, physiological functions, and the removal of cellular damage, including prevention and removal of cancers and other diseases.”
– 21st Century Science and Technology Magazine
See http://radiationhormesis.com/tag/natural-immune-system/
In the high mountains of Colorado, radiation exceeds three times the average in the USA, because of radon and granitic elements.
Colorado natives have much longer life spans, compared to the USA mean.
Causality or correlation?
So wait. 40 Tbls of peanut butter increases my risk of death?
*sigh* I’ll miss you, Favorite Midnight Snack…