Radioactive bananas

Thanks to Webmonk for alerting me to this interesting fact cited at the blog Watts Up With That, which quotes from Wikipedia:

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]

I knew about electrical bananas–name that source! Watson, do you know that kind of trivia?–but not radioactive bananas.

About Gene Veith

Professor of Literature at Patrick Henry College, the Director of the Cranach Institute at Concordia Theological Seminary, a columnist for World Magazine and TableTalk, and the author of 18 books on different facets of Christianity & Culture.

  • Carl Vehse

    In addition to bananas, similar concentrations of potassium-40 are in carrots, white potatoes, lima beans, and brazil nuts. And Brazil nuts also contain radium-226, another radioactive isotope.

    Living at higher elevations increases the radiation dose one gets from cosmic radiation; and there’s more radioactivity in brick or stone houses (espcially some granites) than in wooden houses.

    The irony of natural radioactivity is that every time anti-nuclear people get together for a demonstration or to protest against building nuclear power plants they are exposing themselves to higher levels of radiation from the crowds of people, since each person has about 0.1 microcuries of gamma-ray emitting potassium-40 in his body.

  • Carl Vehse

    In addition to bananas, similar concentrations of potassium-40 are in carrots, white potatoes, lima beans, and brazil nuts. And Brazil nuts also contain radium-226, another radioactive isotope.

    Living at higher elevations increases the radiation dose one gets from cosmic radiation; and there’s more radioactivity in brick or stone houses (espcially some granites) than in wooden houses.

    The irony of natural radioactivity is that every time anti-nuclear people get together for a demonstration or to protest against building nuclear power plants they are exposing themselves to higher levels of radiation from the crowds of people, since each person has about 0.1 microcuries of gamma-ray emitting potassium-40 in his body.

  • http://sbtcross.org Robin Fish

    Donovan, Mellow Yellow – the source of the electrical banana

  • http://sbtcross.org Robin Fish

    Donovan, Mellow Yellow – the source of the electrical banana

  • http://theobservationtree.blogspot.com Louis

    Again, people arecared of radioactivity because they don’t understand it. As Carl said, even we ourselves are radioactive. I did a Radiation Safety Course years ago, and the interesting thing is that people get all up in arms about minor radiation, which totally blends into the background of the natural radiation around us.

    Here in SK we have massive Potash deposits – hence a lot of natural radiation from 4oK decaying to 40Ar. Furthermore, in the north of the province, we have the worlds richest Uranium deposits – in areas the grade is so high that they have to mine it remotely.

    We also have a lot of people in their 90′s around here. Draw your own conclusions :)

  • http://theobservationtree.blogspot.com Louis

    Again, people arecared of radioactivity because they don’t understand it. As Carl said, even we ourselves are radioactive. I did a Radiation Safety Course years ago, and the interesting thing is that people get all up in arms about minor radiation, which totally blends into the background of the natural radiation around us.

    Here in SK we have massive Potash deposits – hence a lot of natural radiation from 4oK decaying to 40Ar. Furthermore, in the north of the province, we have the worlds richest Uranium deposits – in areas the grade is so high that they have to mine it remotely.

    We also have a lot of people in their 90′s around here. Draw your own conclusions :)

  • Jimmy Veith

    Yikes! Could a banana split cause a nuclear explosion? :(

  • Jimmy Veith

    Yikes! Could a banana split cause a nuclear explosion? :(

  • EGK

    So which came first, or what brought this up? This factoid was presented Tuesday night on NCIS: Los Angeles.

  • EGK

    So which came first, or what brought this up? This factoid was presented Tuesday night on NCIS: Los Angeles.

  • http://enterthevein.wordpress.com J. Dean

    Jimmy @ 4: That’s funny!

    I did not know that about bananas. Of course, the way my son eats bananas, I’ll have to start calling him Dr. David Banner.

  • http://enterthevein.wordpress.com J. Dean

    Jimmy @ 4: That’s funny!

    I did not know that about bananas. Of course, the way my son eats bananas, I’ll have to start calling him Dr. David Banner.

  • DonS

    Maybe we should call it a “banana fission”?

  • DonS

    Maybe we should call it a “banana fission”?

  • Carl Vehse

    Too many banana splits could cause an explosion of the waistline.

  • Carl Vehse

    Too many banana splits could cause an explosion of the waistline.

  • http://theobservationtree.blogspot.com Louis

    Gives a whole new level of meaning to “Going Bananas!”

    not say, “Banana Republics”.

    So what you really don’t want is a Banana Republic going bananas :)

  • http://theobservationtree.blogspot.com Louis

    Gives a whole new level of meaning to “Going Bananas!”

    not say, “Banana Republics”.

    So what you really don’t want is a Banana Republic going bananas :)

  • http://www.toddstadler.com/ tODD

    Wait, bananas have potassium in them? I thought their empirical formula was two parts sodium to one part barium.

  • http://www.toddstadler.com/ tODD

    Wait, bananas have potassium in them? I thought their empirical formula was two parts sodium to one part barium.

  • Carl Vehse

    Don’t forget the one part sulfur in bananas.

  • Carl Vehse

    Don’t forget the one part sulfur in bananas.

  • Ted Snedeker

    In ancient Hawaii, bananas were a delicacy and restricted to the royal family. If a commoner was caught eating one bad things could happen, thus bringing bananas on a fishing boat was considered bad luck and would adversely affect ones catch. On the sport fishing boats operating out of Hawaii today that still very much applies, bringing bananas on board is frowned upon. Flowing from that it seemed when video cameras first came out and someone brought one on board to film their adventure for friends and posterity no one caught a fish. Thus, electric banana. (At least at the Honolulu pier)

  • Ted Snedeker

    In ancient Hawaii, bananas were a delicacy and restricted to the royal family. If a commoner was caught eating one bad things could happen, thus bringing bananas on a fishing boat was considered bad luck and would adversely affect ones catch. On the sport fishing boats operating out of Hawaii today that still very much applies, bringing bananas on board is frowned upon. Flowing from that it seemed when video cameras first came out and someone brought one on board to film their adventure for friends and posterity no one caught a fish. Thus, electric banana. (At least at the Honolulu pier)

  • WebMonk

    Tom, as a Pennsylvanian, I assumed Veith was talking about the Electric Banana nightclub. A bit of local color in the Pittsburgh area. I have the vague impression that Veith has some family up that direction.

  • WebMonk

    Tom, as a Pennsylvanian, I assumed Veith was talking about the Electric Banana nightclub. A bit of local color in the Pittsburgh area. I have the vague impression that Veith has some family up that direction.

  • http://www.larrygilman.net Larry Gilman

    Electric Banana refers, of course, to the Donovan Song “Mellow Yellow.”

    There is little real thought behind all the jeering about “banana equivalent doses.” It’s fallacious to assume that radiation from natural sources is harmless: on the contrary, a proportion of spontaneous cancers is likely caused by such sources. Adding to background levels by any amount (e.g., via X-rays or artificial radioisotopes) increases risk. That’s science, not fearmongering: as you may know, the BEIR VII committee reaffirmed a “linear no threshhold” model, i.e., radiation risk should be treated as directly proportional to dose starting at zero dose: http://www.nap.edu/nap-cgi/report.cgi?record_id=11340&type=pdfxsum

    Pronuclear writers have been whooping it up about radioactive bananas for a while now, as if it were new knowledge that low-level radiation is ubiquitous, or as if fear of radiation were laughably irrational. The implication — often stated explicitly — is that opponents of nuclear power are fearful, ignorant fools.

    Just how foolish and how ignorant, one need only look at today’s headlines from Japan to see.

  • http://www.larrygilman.net Larry Gilman

    Electric Banana refers, of course, to the Donovan Song “Mellow Yellow.”

    There is little real thought behind all the jeering about “banana equivalent doses.” It’s fallacious to assume that radiation from natural sources is harmless: on the contrary, a proportion of spontaneous cancers is likely caused by such sources. Adding to background levels by any amount (e.g., via X-rays or artificial radioisotopes) increases risk. That’s science, not fearmongering: as you may know, the BEIR VII committee reaffirmed a “linear no threshhold” model, i.e., radiation risk should be treated as directly proportional to dose starting at zero dose: http://www.nap.edu/nap-cgi/report.cgi?record_id=11340&type=pdfxsum

    Pronuclear writers have been whooping it up about radioactive bananas for a while now, as if it were new knowledge that low-level radiation is ubiquitous, or as if fear of radiation were laughably irrational. The implication — often stated explicitly — is that opponents of nuclear power are fearful, ignorant fools.

    Just how foolish and how ignorant, one need only look at today’s headlines from Japan to see.

  • Pingback: Should we go bananas about Fukushima? | International Times of Dominica

  • Pingback: Should we go bananas about Fukushima? | International Times of Dominica

  • George

    The linear no-threshold is a model for radiation risk to be used for radiation safety purposes. The EPA and all regulatory agencies admit there is a threshold of radiation that is safe. Since that threshold cannot be determined, for safety purposes only, the LNT model is used.

    Nature is always consistent. And in nature, while a lot of something may be bad, a little is usually good. We call it hormesis. Two aspirin makes the headache go away. Two pounds of aspirin tears the stomach lining. Without radiation, you and I would be dead at an early age. We need this minor insults to the body to make it stronger. A body-builder tears muscles down to make them come back stronger. Viruses, dust, pollen all strengthen out immune system. Do you have friends that spend have the day sneezing because they grew up in a “spic-n-span” home and rarely ventured far from video games? I do. They have poor immune systems.

    There are examples galore. But the biggest question to ask is why would nature change the rules just for radionuclides?!

  • George

    The linear no-threshold is a model for radiation risk to be used for radiation safety purposes. The EPA and all regulatory agencies admit there is a threshold of radiation that is safe. Since that threshold cannot be determined, for safety purposes only, the LNT model is used.

    Nature is always consistent. And in nature, while a lot of something may be bad, a little is usually good. We call it hormesis. Two aspirin makes the headache go away. Two pounds of aspirin tears the stomach lining. Without radiation, you and I would be dead at an early age. We need this minor insults to the body to make it stronger. A body-builder tears muscles down to make them come back stronger. Viruses, dust, pollen all strengthen out immune system. Do you have friends that spend have the day sneezing because they grew up in a “spic-n-span” home and rarely ventured far from video games? I do. They have poor immune systems.

    There are examples galore. But the biggest question to ask is why would nature change the rules just for radionuclides?!

  • http://www.larrygilman.net Larry Gilman

    Dear George,

    You write, “The EPA and all regulatory agencies admit there is a threshold of radiation that is safe.”

    Incorrect. The EPA specifically states that it uses the linear-no-threshold model to estimate risk from low levels of radiation: see, for example, http://www.epa.gov/rpdweb00/understand/risk.html .

    The claim about “all regulatory agencies” other than the EPA is similarly inaccurate.

    The rest of your post expands on the notion that “Nature is always consistent,” with extended analogies between body-building, aspirin, acquired immunity, and ionizing radiation. As a scientifically-trained person, or even a person of ordinary reason, I can make no sense of this kind of handwaving. Nature is _not_ always “consistent” in the sense claimed. Ultracold helium does not flow like water at all; electrons do not behave like tiny golf balls at all; there is no reason whatsoever to think that exposure to low gamma rays will produce health effects comparable to exposure to cold germs. Patterns in one realm of phenomena may or may not repeat in other realms. Reasoning by analogy, in physical science, is therefore a recipe for instant and total disaster: which is why we do experiments and gather objective knowledge.

    The state of scientific knowledge on the subject of hormesis has been reviewed and re-reviewed: if you click on the following link, you can see what the US National Academies of Science actually conclude (the BEIR VII document):

    http://www.nap.edu/nap-cgi/report.cgi?record_id=11340&type=pdfxsum (click link for Appendix D)

    The NAS writes,

    “The committee concludes that the assumption that any stimulatory hormetic effects from low doses of ionizing radiation will have a significant health benefit to humans that exceeds potential detrimental effects from the radiation exposure is unwarranted at this time.”

    Contra your opening sentence, BEIR VII nowhere says that the linear no-threshold model applies to some kinds of radiation exposure (“radiation safety”) and not others. It is the scientific consensus model for health-effects calculations involving low levels of ionizing radiation.

  • http://www.larrygilman.net Larry Gilman

    Dear George,

    You write, “The EPA and all regulatory agencies admit there is a threshold of radiation that is safe.”

    Incorrect. The EPA specifically states that it uses the linear-no-threshold model to estimate risk from low levels of radiation: see, for example, http://www.epa.gov/rpdweb00/understand/risk.html .

    The claim about “all regulatory agencies” other than the EPA is similarly inaccurate.

    The rest of your post expands on the notion that “Nature is always consistent,” with extended analogies between body-building, aspirin, acquired immunity, and ionizing radiation. As a scientifically-trained person, or even a person of ordinary reason, I can make no sense of this kind of handwaving. Nature is _not_ always “consistent” in the sense claimed. Ultracold helium does not flow like water at all; electrons do not behave like tiny golf balls at all; there is no reason whatsoever to think that exposure to low gamma rays will produce health effects comparable to exposure to cold germs. Patterns in one realm of phenomena may or may not repeat in other realms. Reasoning by analogy, in physical science, is therefore a recipe for instant and total disaster: which is why we do experiments and gather objective knowledge.

    The state of scientific knowledge on the subject of hormesis has been reviewed and re-reviewed: if you click on the following link, you can see what the US National Academies of Science actually conclude (the BEIR VII document):

    http://www.nap.edu/nap-cgi/report.cgi?record_id=11340&type=pdfxsum (click link for Appendix D)

    The NAS writes,

    “The committee concludes that the assumption that any stimulatory hormetic effects from low doses of ionizing radiation will have a significant health benefit to humans that exceeds potential detrimental effects from the radiation exposure is unwarranted at this time.”

    Contra your opening sentence, BEIR VII nowhere says that the linear no-threshold model applies to some kinds of radiation exposure (“radiation safety”) and not others. It is the scientific consensus model for health-effects calculations involving low levels of ionizing radiation.

  • http://www.larrygilman.net Larry Gilman

    PS. I meant to write “low levels of gamma radiation,” not “low gamma rays.” There is no such thing as a “low gamma ray.” My blushes for the typo.

  • http://www.larrygilman.net Larry Gilman

    PS. I meant to write “low levels of gamma radiation,” not “low gamma rays.” There is no such thing as a “low gamma ray.” My blushes for the typo.

  • dth

    weird maybe thats how u die of old age; too much of thier own radiation!!!!OMG

  • dth

    weird maybe thats how u die of old age; too much of thier own radiation!!!!OMG


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