Is that a Banana in Your Pocket or Are You Radioactive?

"Banana Equivalent Dose" was a concept new to me when it came to my attention via that font of much wisdom and arcana, Paul Kedrosky, who got it from William Gibson's Twitter stream (@GreatDismal).

According to its Wikipedia entry,  "banana equivalent dose (or BED) is a concept 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, or ⁴⁰K they contain. Bananas are radioactive enough to regularly cause false alarms on radiation sensors used to detect possible illegal smuggling of nuclear material at US ports.^[3]

A medium sized banana contains about 450 mg of Potassium.^[4] 0.0117%, or about 53 μg of this being ⁴⁰K. 53 μg of ⁴⁰K produces 14 radioactive decays per second (dps), or 0.00037 μCi of radiation. If the banana is eaten, the dose equivalent is about 0.01 mrem.^[1] 0.01 mrem is equivalent to 0.1 μSv.^[5]

A radiation dose equivalent of 100 μSv (10 mrem, or 1,000 BED) increases an average adult human's risk of death by about one micromort – the same risk as eating 40 tablespoons of peanut butter, or of smoking 1.4 cigarettes^[6]

Here is a link to the full entry: Banana Equivalent Dose.

In the coverage of the Japan's Fukushima nuclear plants SI multiples have been used, including the millisievert  and microsievert.  There was some confusion about this yesterday in the news as a spike was observed.

A millisievert (mSv) is a thousandth of a sievert and a microsievert is a millionth of sievert.  A chest x-ray has 0.1 mSv.  (Peter Wehrwein,editor of the Harvard Health Letter, has a good discussion of the topic at the Harvard Health Blog.)

Yesterday's spike at the Fukushima Dai-chi plant was 400 mSv per hour.  Sounds like a bunch of bananas.

 

Related articles

• Will US West Coast Citizens Exceed Banana Equivalent Dose? (treehugger.com)
• Banana dose equivalents of radiation (nextbigfuture.com)
• Radioactive bananas (geneveith.com)
• Putting a radiation rumor to rest (michellemalkin.com)
• Radiation Exposure: How Much Is Too Much? (destructionist.wordpress.com)

Green Skeptic Friday LinkFest - 01/07/11

Hockey in 1901.

A new year and some of the same old arguments and debates.  Will this be the year we break the logjam and get the new green economy running in the US?

Here are my links for the first week of the new year:

The Breakthrough Institute's Shellenberger and Nordhaus on Why Climate Science Divides Us But Energy Technology Unites Us

The new Chair of the House Science and Technology Committee, Texas Republican Representative Ralph Hall is not a climate skeptic.  He believes it is happening but wants to Probe 'Quality' of Climate Science

In a curious twist, the Sierra Club is suing to stop a landmark solar development: Whose Side Are They On?

Meanwhile, China's Goldwind wins wind energy order of 76.5 MW in Ethiopia: Goldwind.

and Arch, Peabody seek coal exporting deals to Asia. 

Ciris Energy raised $24 million to biochemically convert coal to methane at large scale and low cost: Serious about Ciris,

and battery company Ener1 Completes $25 Million Capital Raise, while

CleanTechies blog speculates that Electric Vehicles are in for Remarkable Ride in 2011.

And, finally, Paul Kedrosky talks about the "Webification" of Energy in Harvard Business Review's HBR Agenda 2011.

Have a great weekend everybody.

World Statistics Day Energy Quiz

Paul Kedrosky pointed me to this energy statistics quiz from the Energy Information Administration.

I scored 18/20, missing on questions 3 & 4 (duoh!).

See how well you do: US Energy Information Administration Energy Quiz

Did you know there was such a thing as World Statistics Day?

Your Long-Suffering Audience

The title of this post could be "The companies weren't bad, but their presentations weren't any better."

But I'll go easy. (Hell, I've been guilty too...)

It's not that the presentations were bad, necessarily; well, okay, they were. Yet some had useful information either about the company, the sector, the pain they were addressing, or the solution they proposed. Some even had realistic projections and maybe even a pithy quotable line or two.

Really, I suspect none of the presenters spent sufficient time on their presentations; especially on cutting them. (Wasn't it Pascal who said, he "made this [letter] longer, because I have not had the time to make it shorter"?)

Or thinking through their audiences.

Oh, speaking of audiences: If you're doing a keynote, especially first thing in the morning or just after lunch, do something different. Use your OWN knowledge of the topic to craft your points and don't really on someone's data points or best-selling book to get your message across.

And don't assume that the audience either knows too little or too much about your topic. (Especially after you've ask them who they are. If you're going to ask, you need to adjust accordingly.)

Paul Kedrosky posted some good tips for better presentations (or at least quirkier ones), which has my vote: paulkedrosky.com

And, of course, there is always something worth reading at Presentation Zen.

Before you commit a presentation misdemeanor, consider the alternatives. And respect your audience.