Feature:Opinion

Going bananas over radiation

With all the worries over radiation leaks from Japan, and hoarding of potassium iodide tablets, many people might be surprised to learn that they will get more radiation from eating a single banana today than they will from Japan’s nuclear reactor problems.

While doing some research on Thorium reactors, 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 radiation-free lives. I’ll never forget the time 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 (BED) is a concept occasionally used by nuclear power proponents to place in scale the dangers of radiation by comparing exposures to the radiation generated by a common banana. Bananas are high in potassium, and naturally radioactive, due to the isotope potassium-40 they contain. One BED is the radiation exposure received by eating a single banana.

Bananas are radioactive enough to cause false alarms on radiation sensors used to detect possible illegal smuggling of nuclear material at U.S. ports. After the Three Mile Island nuclear accident, the Nuclear Regulatory Commission detected radioactive iodine in local milk at levels of 20 picocuries/liter, a dose much less than one would receive from ingesting a single banana.

So, before you throw money away on Geiger counters and potassium iodide pills, think about how many bananas you eat in a week.

If you are still worried about radiation from Japan, you can watch radiation levels on the west coast of the U.S.A. live on this map of the radiation monitoring stations operated by citizen science volunteers here.

Anthony Watts operates the most visited blog on climate science in the world, www.wattsupwiththat.com.