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.
Good fun,
All the earth first ones who live in Aspen, Teluride, Durango, Leadville Colorado.
Get them to one of the old down town buildings for tea and crumpets. Have G-counter ready after the drink a bit, turn it on, hold it up to the bricks (made with the mine tallings) ya, lots of watse U-238 etal.
ttttttttttt real fast it does
So that explains Lancelot Links….
I think you meant to put “the average person doesn’t really know a lot about science” after the colon.
Regarding C14 (AnonyMoose – February 16, 2011 at 10:46 am), Isaac Asimov wrote an essay back in the ’60s (I think) speculating that C14 decay might be a cause of cancer. He guesstimated the number of genes containing C14 in a human body and then the number daily that would be damaged by decay. I don’t remember the number (it’s been 40 years since I read the article), but it was astonishingly large – thousands? millions? per day.
The Gray Monk says:
February 16, 2011 at 11:48 am
“Sadly, the morons of Greenpeace et al and the Campaign for Nuclear Disarmament failt o make a distinction between the two types.”
It has never been the purpose of Greenpeace or the Greens to inform people; for Greenpeace, a scare means money, for the Greens, power.
I love this article. Kudos to Anthony for making me a little less ignorant.
Your link to Wikipaedia for Brazil Nuts gives a more modest 1–7 pCi/g (40–260 Bq/kg). Lets assume 5 pCi/g or about 0.185 Bq/g as a reasonable mean. Further assume a modest 25 g, just under and ounce a day, for 365 days. I think this is not unreasonable. I try to eat at least this amount of nuts every day although not usually Brazil nuts. This amounts to an intake of about 68 Bq per year. This is radium however, the cancerous radiotoxin of the radium dial illuminators so more radiotoxic than K-40.
Using ICRP Publication 68 dose coefficient of 2.8E-7 Sv/Bq for radium-226 gives the Brazil Nut Equivalent Dose, BNED, of 0.0000189 Sv or 0.0189 mSv or about 1.9 mrem/year. So even though the biomass intake is less it’s still of the same order of magnitude as your BED.
Go back to your Wikilink for these nuts and note the supposed prostate cancer reducing properties of the high levels of selenium in Brazil nuts and all the other high value nutritional components of this food. Dr. Oz was touting larger intakes of Brazil Nuts as a pathway to good health and longevity last week. My wife thought we should buy lots of Brazil nuts,. I am happy with that because I like them.
So I leave you with this little conundrum in risk management – which is what so much of safety and healthcare is all about. Should you eat them and take advantage of their health benefits or avoid them to minimize the risk of bone cancer.
My sibling and I look rather different – I’m short and fair, sib is taller, leaner and much darker. When we were small, people would look at us and our parents and speculate. Some inquired as to which parent worked at the local nuclear facility. Others would ask what our Mom and Dad did for a living, and upon being told that one parent is a radiologist, the curious soul usually went “ah, thank you,” and gave us a knowing look. Actually, it is normal genetic variation derived from our very diverse family tree (Scots-Irish, English, Dutch, Cherokee, French).
Antony, why dont you talk about Chernoby?
Care to talk about and show photos of the children being born deformed?
how long will the site remain radioactive?
REPLY: get your own blog and you can talk about Chernobyl all you want, this thread is about Potassium-40 in bananas. – Anthony
How will the horror of the radioactive banana be spread to the cowering masses of right-thinking people everywhere?
By pressing a cellphone to the side of the skull, naturally.
But first, it’s time for a lunch warmed up in the 25 year old office microwave.
This topic brought up two memories.
1. – Sensing the absurdity of the EPA standards, Dr. Michael Gough and I commissioned radiation experts to measure radiation levels in the U.S. Capitol building and compare them with the proposed Yucca Mountain standards. The Capitol contains a great deal of granite and marble building materials that naturally emit the same type of radiation as spent fuel.
Our experts discovered that radiation dose rates at the Roger Williams statue, located between the Rotunda and Senate Chamber, are up to 65 times greater than what the EPA plans to allow at Yucca Mountain.
The radiation-dose rate at the Williams statue also is up to 550 percent higher than the dose rate received at the fence-line of a nuke plant, and about 13,000 times higher than the average annual radiation dose from worldwide nuclear-energy production. http://www.foxnews.com/story/0,2933,21015,00.html
2. – Back in the mid 70’s, some state legislator wanted a zero emission rate for any radioactive waste flow, until someone realized whiskey contains radioactive materials, so they would have to shut down all the bars.
I work in the nuclear industry also, but don’t recall the Banana Dose Equivalent. What I have always gotten a kick out of is the example of sleeping next to your spouse or significant other – your annual dose of sleeping in the same bed with someone is roughly the same as getting a chest x-ray. Why? Because of the naturally occurring potassium 40 in each of us. We not only irradiate ourselves constantly, but also anyone that we are in very close proximity to.
The other example I often use is a round trip flight from NY to LA & back, which is also about the equivalent of a chest x-ray.
Or telling folks that the fact is you are safer actually working in a nuclear power plant than in your own home. Darned all those kids toys to trip over, stairs folks fall down, ladders…. You ARE literally safer and less likely to be injured or killed working in a nuclear power station than in the typical American home. Folks who work in nuclear facilities are also healthier than those who don’t – it’s called the ‘healthy worker effect.’ Who knows why, and there are a number of different theories on that one.
Others here have mentioned the old Fiesta Ware – those are actually valuable as collectors items, but really do give off an amazingly large dose. Old watches with glow in the dark dials do also – they used to use tritium paint. One very innocuous item that is fun to use as an example of how incredibly sensitive even the oldest Geiger counters are, is a Colman lantern mantle. They’ll make a counter go from the slow tick tick of natural background radiation levels to screaming absolutely wild. Talk about an eye opener for many folks.
Many years ago you could go to shoe stores and put your foot into a fluoroscope – and wiggle your toes and watch your skeleton bones move in the scope. They were used to fit your shoes. I’d LOVE to be able to play with one of those, but they gave you a really high dose and needless to say you can’t just get your hands on one and play with it anymore. http://www.orau.org/ptp/collection/shoefittingfluor/shoe.htm
Frustrating regulatory factoid — The EPA limit for radon in drinking water is actually LOWER than the naturally occuring amount in some natural springs or water from natural aquifers. Seems to me that’s just yet another example of regulatory overkill, based on very unsound ‘science.’ There is zero evidence that those levels, even if that’s the only water a person had access to their entire lives, would cause any harm what-so-ever. But EPA protects us all from it none-the-less.
Meanwhile, Anthony, if you knew how that estimate of “increased risk of death” from 10 mrem was determined you’d be appalled. Its strictly based on calculation and assumption – and those calculations have multiple different factors of conservatism thrown in (e.g., if we think it’s this much, double it in the direction of worse effect than we think, just to be safe), and the assumptions are of a linear dose effect, no threshold (virtually unheard of in biological systems)… with the primary data used being from acute high level exposures such as from Hiroshima and Nagasaki. Not from low level non-acute exposures.
Which leads right into the whole “risk from radon exposure” b.s. that’s out there. That’s a very very similar situation for low level doses – all calculated, many questionable assumptions. There are only a very few areas of the country where radon exposure in homes is even the slightest concern – areas over the right type of bedrock. Even there you ONLY have a risk in relatively air tight basements or crawl spaces – and even then only if you spent many hours every day for a long time in those areas. Or very very rarely in the few super air tight homes that a few folks have built. For the most part even then the “risk” is questionable – there is a fair amount of solid experimental evidence of radiation hormesis – e.g., improved health or biological benefits to some radiation exposure that is significantly higher than we are typically exposed to.
I recall one example I was told about by one of my professors back in grad school. An experiment was done using mice being exposed continuously to what would be considered to be a very high dose rate…. I wish I could recall the dose rate, but darned if I can – it was far higher than any typical nuclear power plant worker would be exposed to however if they lived in the plant 24/7/365. Far higher than normal background radiation rates. Still in the mRem range tho, not a super high dose. Anyhow, they were looking at litter size, fertility rates, mutations, birth defects, etc. They didn’t check life span tho (which would have taken a lot longer obviously). They continued for 20 generations this way, all being dosed continuously. Zero reduction in fertility rates, zero increase in any birth defects or notable health problems, just nothing – no detectable ill effects. In the last generation, however, they noticed one mouse that seemed entirely healthy but had a respiration rate that was half normal. It turned out that there was some mutation that allowed it’s oxygen transfer/usage to be twice as efficient. Go figure (and talk about intriguing as all heck, a biochemist or plenty of other researchers probably would have loved to get their hands on that mouse for study!!).
One other thing that always amazes me – how many people seem to think that a single smidge, a tiny drop of radiation, will make an area deadly and radioactive for thousands of years and that there’s nothing that can be done about it. Many people don’t seem to realize that generally if something becomes contaminated (say areas within a nuclear power plant, or from a dirty bomb, or whatever), then it’s a relatively simple matter to just clean it up just as you would cleaning dust out of your house. Sure, with a few extra precautions to contain that ‘dust’ and not let any of it spread and to keep it from contacting the skin of those doing the cleaning, but still – often it’s very easy to clean up any contamination and then the area isn’t the least bit radioactive or dangerous any more. Other than those actually hurt or killed by the bomb blast itself (as they would be for any bomb, dirty or not), the most actual harm to humans from a dirty bomb would be from panic, NOT from the radiation. It’d be a pain to clean up, no question, but the panic from folks who don’t understand the real risks would be the killer, not any residual radiation.
As to how easy cleanup of radiation contamination is in general – obviously there are exceptions and it depends on whether any of the radioactive material has become actually embedded in the structures involved, and the ease of clean up also depends on the type and amount of radiation involved… but the point is that many many people don’t realize that particulate radiation, e.g., ‘contamination,’ can typically be fairly easily removed with no ill effects and no residual radiation remaining. Reality is a world of difference from the all too common perception of “one drop of any type of radiation on this floor and it, the ground, the room, the building, all will be deadly for the next 10,000 years and nothing can be done to change that other than cordon off a large area around it and keep everyone out.”
Oh, and speaking of hormesis – VERY interesting tidbit I ran across a few weeks ago. Apparently getting 3 CT scans of your chest over a few years actually cuts your risk of coming down with lung cancer by about 20%. CT scans give you a very high radiation dose (relatively speaking). http://opinion.financialpost.com/2010/11/05/lawrence-solomon-the-scan-that-cures/
Oh, and I almost forgot – last I knew you could still go and get your hormesis dose in “health spas” if you want to…. in, I think, either Wyoming or Montana – these are “spas” where you go into underground tunnels and stay there for awhile, specifically for the increased radiation dose you receive naturally from the increased levels of radon. There are similar ‘health spas’ in other nations too. I don’t know if this is still the case, but it used to be that you’d get a far higher dose there than would be allowed for mine workers or other occupational doses for people working in underground tunnels.
Ah, well, what an amazing world we live in.
Not only does the type of emission matter, but where it goes matters. For example, radioactive iodine can be efficiently collected in the thyroid.
Generally speaking, external gamma emitters are a problem, but internal gamma emitters are not because most of the energy emitted from inside the body is absorbed outside the body. Gamma rays have low energy transfer characteristics.
Alpha is the opposite extreme. High LET and a big problem if ingested, but the skin is enough protection for external exposure. Beta is intermediate. With external exposure, it penetrates the skin a little. Beta is more of a problem with internal exposure where most likely all of the energy emitted will be deposited within the body.
The danger from radiation exposure is not so much in direct modification of DNA by breaking the phoshoribosyl backbone (and both strands have to break for repair to be problematic). The exception is internal alpha. The major problems are due to the production of highly reactive hydroxyl radicals derived from water made more potent by subsequent reaction with oxygen to create peroxide radicals. Both of these can travel a short distance through the medium surrounding DNA and modify the bases and backbone. This process greatly increases the effective cross-section of DNA for mutation-producing effects of radiation.
40K emits a beta particle with about the same energy as 32P. We used to do DNA sequencing by labeling DNA enzymatically. I loved to hear the Geiger counter scream when I ran it over the gel. That meant I had a good sequence. I wasn’t worried at all about my exposure because I knew it wasn’t significant compared to my every day background dose from the natural abundance of 40K.
People were irrationally scared of 32P. A market for 35S sequencing was developed. 35S emits a much weaker beta particle. I hated it. Not only were my sequences of poorer quality, but it was harder to detect 35S contamination. I considered 35S to be in fact more risky than 32P because it was harder to know where it was.
Back to potassium…. Sea water has 40K at 300 pCi/L (http://www.physics.isu.edu/radinf/natural.htm). A long time ago, I was told by a radiation safety officer that sea water could technically fall into the category of radioactive waste. I tried to verify that claim today. I didn’t find any solid answer, but I wouldn’t be surprised if it turned out to be true.
My God, no wonder my eyes glow in the dark! I eat a banana and 2 brazil nuts a day.
I have it on good authority from a doctor friend that brazil nuts contain selenium which is a fantastic anti-oxidant and preventer of prostate cancer.
I am still breathing so obviously the brazil nuts act as a radiation treatment as well as providing the benefits of selenium.
@Taphonomic-
Given that every taxpayer is also a consumer of electricity, I’d say that we do indeed subsidize the storage and disposal of spent reactor fuel.
September 24, 2010 – 10:08 pm
Financial Post
Lawrence Solomon: Radiation’s benefits
http://opinion.financialpost.com/2010/09/24/lawrence-solomon-radiations-benefits/
“Will a gamma ray a day keep the doctor away? A new book says low-level radiation may prevent cancer”
As has been pointed out… There is some rethinking required! GK
Re: Drivel:
http://www.globalsubsidies.org/en/subsidy-watch/commentary/gambling-nuclear-power-how-public-money-fuels-industry
http://www.nrdc.org/nuclear/pnucpwr.asp
http://www.grist.org/article/nuclear-pork-enough-is-enough/
Includes sloppy/fraudulent incidents including whistle blower:
http://www.lutins.org/nukes.html
Just to see how touch and go Brown’s Ferry REALLY was:
http://www.ccnr.org/browns_ferry.html#ma
http://en.wikipedia.org/wiki/Three_Mile_Island_accident_health_effects
Local resident reports:
The official figures are too low to account for the acute health effects reported by some local residents and documented in two books;[5][6] such health effects require exposure to at least 100,000 millirems (100 rems) to the whole body – 1000 times more than the official estimates.[7] The reported health effects are consistent with high doses of radiation, and comparable to the experiences of cancer patients undergoing radio-therapy,.[8] but have many other potential causes.[7] The effects included “metallic taste, erythema, nausea, vomiting, diarrhea, hair loss, deaths of pets and farm and wild animals, and damage to plants.”[9] Some local statistics showed dramatic one-year changes among the most vulnerable: “In Dauphin County, where the Three Mile Island plant is located, the 1979 death rate among infants under one year represented a 28 percent increase over that of 1978, and among infants under one month, the death rate increased by 54 percent.”[4]
Health effects probably caused by media caused stress from scare stories, surely not from any cover up to alleviate insurance pay outs. Sarc/off
Jeez, might actually try doing some Googling first, after all thats what it’s for.
This is no laughing matter.
A cascade of 5000 centrifuges can produce “weapons grade” bananas!
DD More says:
February 16, 2011 at 12:43 pm
“Back in the mid 70′s, some state legislator wanted a zero emission rate for any radioactive waste flow, until someone realized whiskey contains radioactive materials, so they would have to shut down all the bars.”
___________________________________________________________
No, Officer. I ain’t drunk…I’m radioactive. Y’all better get back in your car and drive away. Drive safely and have a nice day.
This article freaked me out. I’m a programmer. I’ve never heard of this stuff. My chemistry teacher never talked about this. Well, maybe he did and I wasn’t listening. Bananas and peanut butter are radioactive? Potatoes? I suppose cows glow in the dark too? “glass of the slightly radioactive milk”??? These cows gotta be visible from the moon, no?
And… and someone says my alcohol is radioactive? Gives a whole new meaning to alcohol poisoning.
Seriously though, it’s not often that I read about something I’ve NEVER heard anything about AT ALL. NADA. ZILCH. I’m still freaked out. Every line I’m reading, I’m like “Whaaaaa???”. Damn, I feel stupid. How could I never have heard about this? I did know about gamma rays tho. But whatever. Luminiferous cows, man!
I would luuuv to see the looks on people’s faces if they saw a plot of the ERAMS data. I viewed it as part of a human health risk assessment project once. It showed the amount of radiation floating around in the air during the 50s and 60s when nuclear weapon development was all the craze. The levels were off the chart … yep .. we were breathing many banans worth of radiation at that time. As the testing came to an end, levels dropped to about nothing. OH .. and there it was .. this tiny blip representing Chernobyl …. and 3 mile island didn’t even measure. Ever since then, I don’t worry much about it, and a huge fan of nuclear power.
We NEED nuclear power … if we are ever going to become energy independent.
I went on a visit to a nuclear power plant many years ago. Before entering the reactor building we were all checked for radiation with a hand held Geiger counter. It was clicking away randomly, which naturally had some folks concerned. The guide then held it up to his luminous watch (shows how long ago this was!), and it went crazy… A very effective way of putting peoples minds at rest!
Fear of radiation is silly. The only way to go through life while not exposing yourself to natural radiation is to simply kill yourself .00001 seconds after birth. Even that is iffy, there’s no guarantee you’re not getting some while in the womb.
Well I wouldn’t put a lot of stock in that use a truck load of bananas to hide your nuke in.
K40 is a beta and gamma emitter, with a half life of 1.3 E+9 years. It is 0.0118% of natural Potassium, and emits an electron with 1.32 MeV energy. It can also capture an orbital electron and that is a 1.51MeV event. The electron emission (beta decay is accompanied by a 1.46 MeV gamma.
The Beta electron, is not likely to penetrate far into organs or cells; the gamma is a bit more of a problem.
But your nuke, is almost certain to be emitting fast neutrons; which are not going to look like bananas..
Anthony,
Its even worse. A 70kg man contains about 4.26kBq of Potassium 40 equivalent to 115,135 picocuries. Its obviously very important to make women aware of the potential radioactive risks associated with lovemaking with their partners 🙂