# Radioactive Bananas **URL:** \ **Category:** Factual Questions\ **Created:** [July 27, 2000, 2:30pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052 "2000-07-27T14:30:49Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![lissener](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lissener/32/6139_2.png) [@lissener](https://boards.straightdope.com/u/lissener)\ **Post date:** [July 27, 2000, 2:30pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/1 "2000-07-27T14:30:49Z")
No, it’s not a new rock band. A friend of mine told me a story about a crazy lady she knows who insists that bananas are radioactive; that each banana consumed provides more recommended daily allowance of radiation than passing through an airport metal detector. In fact she insists that a previous employer (who shall remain nameless but is a mega conglomerate that has a large stake in agriculture) tracked emplyees’ air travel and asked them to maintain logs of banana consumption, both for employees’ health records. Anyone have any idea if there’s a grain of truth to this? ---
**Author:** ![TheThill](https://avatars.discourse-cdn.com/v4/letter/t/35a633/32.png) [@TheThill](https://boards.straightdope.com/u/TheThill)\ **Post date:** [July 27, 2000, 2:52pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/2 "2000-07-27T14:52:51Z")
I don’t know about their being radioactive. But I’ve read information about their being sprayed intensively with poisonous chemicals. The shame is that the chemicals are not particularly harmful to the consumers (since the peel is thrown away) but can be deadly harmful to the poor plantation workers. It has in fact been linked to children’s deaths in Central America, etc. I no longer buy (non-organic) bananas. ---
**Author:** ![jayron\_32](https://avatars.discourse-cdn.com/v4/letter/j/41988e/32.png) [@jayron\_32](https://boards.straightdope.com/u/jayron_32)\ **Post date:** [July 27, 2000, 3:39pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/3 "2000-07-27T15:39:28Z")
Banana’s contain a lot of potassium. .01%(or 100 ppm) of naturaly occuring potassium is potassium-40, a radioactive isotope (all of the rest is potassium 39, a stable isotope, and potassium 41, another stable isotope.) The half-life of potassium-40 is on the order of 1.2 billion years, about the same half-life as Uranium 235, the primary contituent of Nuclear reactors. This doesn’t sound like much, but in a 1 gram sample of potassium, that means that there are about 1.505 quintillion, or 1.505 x 10[sup]18[/sup], atoms of potassium. This is enough to send a geiger counter WILD. For comparison, sodium and calcium, which have comparitive abundances and usefulness in the human body, have NO known naturally occuring radioisotopes. It has long been speculated that iradiation due to potassium-40 decay may be the primary cause of genetic mutation in life. So yes, bananas are radioactive, but this is a naturally occuring phenomenon that has nothing to do with man. There are lots of natural sources of radioactivity that have nothing at all to do with nuclear waste. And no, this does not pose any real health risk. Your body contains far more potassium-40 than a banana, and it is hapily decaying in your cells right now. ---
**Author:** ![jayron\_32](https://avatars.discourse-cdn.com/v4/letter/j/41988e/32.png) [@jayron\_32](https://boards.straightdope.com/u/jayron_32)\ **Post date:** [July 27, 2000, 3:41pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/4 "2000-07-27T15:41:31Z")
That should say that there are 1.505 quintillion atoms of potassium-40 in every 1 grams sample of naturally occuring potassium. The rest is Potassium-39 and Potassium-41. ---
**Author:** ![lissener](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lissener/32/6139_2.png) [@lissener](https://boards.straightdope.com/u/lissener)\ **Post date:** [July 27, 2000, 3:50pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/5 "2000-07-27T15:50:35Z")
But again, how does this compare to the radiation received when passing through an airport metal detector? Different type? Different effect? Different level? ---
**Author:** ![TNTruth](https://avatars.discourse-cdn.com/v4/letter/t/d9b06d/32.png) [@TNTruth](https://boards.straightdope.com/u/TNTruth)\ **Post date:** [July 27, 2000, 4:04pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/6 "2000-07-27T16:04:03Z")
Your friend is confusing the metal detectors with the luggage X-ray machines. The metal detectors create an electromagnetic field and sense the distortion in that field caused by a dense object, like my head. They emit no ionizing radiation. ---
**Author:** ![Achernar](https://avatars.discourse-cdn.com/v4/letter/a/e274bd/32.png) [@Achernar](https://boards.straightdope.com/u/Achernar)\ **Post date:** [July 27, 2000, 4:07pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/7 "2000-07-27T16:07:48Z")
Strangely enough, I am _not_ prone to frequent mutations. I didn’t think anything of it, but now that you mention it, I don’t eat a lot of bananas! How could there not be a connection?! ---
**Author:** ![lissener](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lissener/32/6139_2.png) [@lissener](https://boards.straightdope.com/u/lissener)\ **Post date:** [July 27, 2000, 4:08pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/8 "2000-07-27T16:08:35Z")
Does this mean that one receives absolutely zero radiation when passing through an airport metal detector? Less than eating a single banana? Can anyone confirm this for me, or suggest where I can have it confirmed? ---
**Author:** ![Inky\_1](https://avatars.discourse-cdn.com/v4/letter/i/7feea3/32.png) [@Inky\_1](https://boards.straightdope.com/u/Inky_1)\ **Post date:** [July 27, 2000, 4:28pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/9 "2000-07-27T16:28:33Z")
Once when I was a kid my dad brought home a Giger counter from work (they used it to check seals or something) and to our horror the thing went off on a container of salt substitute. Think theres any relation to the potassium? ---
**Author:** ![TNTruth](https://avatars.discourse-cdn.com/v4/letter/t/d9b06d/32.png) [@TNTruth](https://boards.straightdope.com/u/TNTruth)\ **Post date:** [July 27, 2000, 5:05pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/10 "2000-07-27T17:05:53Z")
OK, for all you people who need a “site cite”, here it is: [http://micro.magnet.fsu.edu/electromag/java/detector/](http://micro.magnet.fsu.edu/electromag/java/detector/) Note that the detector does not respond to density, but to electrical conductivity. The detector induces, and senses, an eddy current on the target’s surface. ---
**Author:** ![douglips](https://avatars.discourse-cdn.com/v4/letter/d/e68b1a/32.png) [@douglips](https://boards.straightdope.com/u/douglips)\ **Post date:** [July 27, 2000, 7:13pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/11 "2000-07-27T19:13:15Z")
> [@](#): > > \*Originally posted by lissener \* > \*\*Does this mean that one receives absolutely zero radiation when passing through an airport metal detector? Less than eating a single banana? > > Can anyone confirm this for me, or suggest where I can have it confirmed?\*\* The key word was ‘ionizing’. You are receiving radiation right now from your computer monitor, from the lights in your room (incandescent of flourescent) from the wiring of your house, from the neighbors toaster, and from the radio station on the top of the hill outside of town. All of these sources (well, OK, maybe you get some Xrays from the monitor) are non-ionizing radiation which includes radio waves and light waves. This is a far different story from ionizing radiation, such as the hard gammas emitted by K[sup]40[/sup], an X-ray machine, or cosmic rays when flying in an airplane or living in Denver (high altitudes.) When you hear the word ‘radiation’, don’t panic. It’s just the ionizing kind that matters, and you can’t help but get some of that anyway. So, yes, a banana is more radioactive than the metal detector at an airport, but that means about as much as saying the banana is more radioactive than your dog. Yes, the radiation from a banana is potentially harmful, but it is all a matter of dose. If you lived in Denver for a year you’d get much more radiation than if you ate a few bananas this week. Since I don’t know the actual dosage, perhaps someone can find a page at LLNL or Los Alamos describing various radiation doses (e.g. 1 hour in a plane = 1 week in Denver = 32 bananas = 1 chest X-ray etc.) ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [July 27, 2000, 7:17pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/12 "2000-07-27T19:17:14Z")
> [@](#): > > \*Originally posted by lissener \* > \*\* that each banana consumed provides more recommended daily allowance of radiation \*\* Now I’m worried that I’m not getting enough radiation. ---
**Author:** ![Phobos](https://avatars.discourse-cdn.com/v4/letter/p/3d9bf3/32.png) [@Phobos](https://boards.straightdope.com/u/Phobos)\ **Post date:** [July 27, 2000, 8:23pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/13 "2000-07-27T20:23:14Z")
a douglips said, the word “radiation” does not mean something harmful. all light is radiation. heat is radiation. etc. etc. the concern is over something that is “radioactive” (also known as nuclear radiation, or “nucular” if you’re a Republican Pres. candidate :)) ---
**Author:** ![TNTruth](https://avatars.discourse-cdn.com/v4/letter/t/d9b06d/32.png) [@TNTruth](https://boards.straightdope.com/u/TNTruth)\ **Post date:** [July 27, 2000, 8:40pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/14 "2000-07-27T20:40:05Z")
That was Jimmy Carter’s favorite word. “Don’t worry, Ah’m a nucular engineer.” ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 27, 2000, 8:48pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/15 "2000-07-27T20:48:04Z")
While we’re comparing dosages, how about the amount of dangerous radiation from ordinary sunlight, at sea level? Most of the really hard stuff (X and gammas) is blocked by the atmosphere, but far UV is ionizing, too, and a lot of that can get through. ---
**Author:** ![Phobos](https://avatars.discourse-cdn.com/v4/letter/p/3d9bf3/32.png) [@Phobos](https://boards.straightdope.com/u/Phobos)\ **Post date:** [July 27, 2000, 9:12pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/16 "2000-07-27T21:12:05Z")
EPA’s 2 cents on sources of radiation…(no bananas listed though)…[http://www.epa.gov/radiation/ionize2.htm](http://www.epa.gov/radiation/ionize2.htm) ---
**Author:** ![tcburnett](https://avatars.discourse-cdn.com/v4/letter/t/c5a1d2/32.png) [@tcburnett](https://boards.straightdope.com/u/tcburnett)\ **Post date:** [July 27, 2000, 9:31pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/17 "2000-07-27T21:31:07Z")
> [@](#): > > \*Originally posted by lissener \* > **A friend of mine told me a story about a crazy lady she knows who insists that bananas are radioactive** The operative word here is “crazy”. I eat a lot of bananas and I hardly glow at all. ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [July 27, 2000, 11:44pm UTC](https://boards.straightdope.com/t/radioactive-bananas/27052/18 "2000-07-27T23:44:18Z")
Bananas are not the only good source of radiation. > [@](#): > > Very good sources of potassium include banana, cantaloupe, grapefruit, orange or tomato juice, honeydew melon, molasses, prunes, prune juice and white potato