Some of the bananas around Fukushima may be radioactive but what about the bananas at your local grocery store? Those bananas aren’t radioactive, right? Surprisingly, they are. All bananas are naturally radioactive thanks to potassium. Specifically, the potassium-40 isotope.
I’m Eating Radioactive Bananas?!
Yes, but don’t freak out just yet. You’re exposed to radioactivity every day. Even right now, you are exposed to background radiation simply by living on the Earth. On an average day, for an average person, they will be exposed to 10.0 μSv worth of background radiation (μSv, or microsieverts, is a unit used to measure radioactivity). Did you know that you are also naturally radioactive? By sleeping next to someone, you are exposing that person to .05 μSv worth of radiation. Living in a stone or brick house will expose you to 70 μSv per year.
Thanks to the radioactive isotope potassium-40, eating one banana will expose you to about 0.1 μSv. This natural radioactivity has led to a unit of measurement called the “banana equivalent dose” or BED. It is defined as the radiation absorbed by a person due to eating a single banana. It’s purpose is to help put radioactivity in perspective for those who are unfamiliar with radiation measurements and scales.
Any Need To Worry?
No. There is absolutely no need to be concerned. You are exposed to radiation every day. Even if you lived next to a nuclear reactor (barring a major reactor meltdown) there should be no cause for worry. In fact, research has even begun to indicate that these extremely low level amounts of radiation you experience (from naturally occurring background radiation, bananas, your computer monitor, etc), may actually be beneficial to your body. And as far as major reactor problems go, if you camped out at the Three Mile Island nuclear plant during the accident that happened in 1979, you’d have received only an additional 80 millirems of radiation during the the accident. Granted, you’d need to eat about 8000 bananas to reach that level from bananas, but if you’ve ever had a back x-ray, you would have received double that amount.
This is part of the reason why the ‘banana equivalent dose’ was created. To help avoid public hysteria when talking about radiation levels and inform people that they’re exposed to radiation every day despite many people not being aware that they are, or just how much. No matter how many bananas you eat, you’re not going to turn into the incredible hulk.
Bonus Science Facts:
- If you live at higher elevations, like Denver, you are exposed to about 50-70 more millirems per year than living in New York city (sea level).
- At 100 rems (10 million bananas), you’ll contract mild radiation sickness. Early symptoms of this resemble the flu.
- Around 400 rems (40 million bananas), you have a 50/50 chance of dying within 60 days if you don’t seek immediate treatment.
- Many other common foods are naturally radioactive. These include potatoes, sunflower seeds, kidney beans and many different nuts. The most radioactive by far is the Brazil Nut. One Brazil nut is equivalent to 1.8 BED (banana equivalent dose). This is thanks to the high levels of radium in the soil where the plant grows.