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Banana Equivalent Dose

                                        - Captain Internal Dosimetry!

                                      Banana Equivalent Dose

re:  The Radiation Dose from a "Reference Banana."

Some time ago (when I almost had time to do such things) I calculated the dose
one receives from the average banana.  Here's how it goes:

On page 620 of the CRD Handbook on Rad Measurement and Protection, the
concentration of K-40 in a "Reference Banana" is listed as 3520 picocuries per
kilogram of banana.  For those of us who are stuck in certain unit ruts, this
is equivalent to 3.52E-6 microcuries of K-40 per gram of banana.

An average "Reference" banana weighs (masses) about 150 grams (I think.)  So,
the ICRP Reference Banana contains about 5.28E-4 microcuries of probably
deadly K-40.

Federal Guidance Report #11 lists the ingestion dose (committed effective dose
equivalent) for K-40 as 5.02E-9 Sv/Bq or (again, for those of us who are
"unit-challenged," 1.86E-2 rem per microcurie ingested.)

Thus, the CEDE from ingestion of a Reference Banana is 5.28E-4  x 1.86E-2 =
9.82E-6 rem or about 0.01 millirem. 

I have found this "Banana Equivalent Dose" very useful in attempting to
explain  infinitesmal doses (and corresponding infinitesmal risks) to members
of the public.  (Interestingly, the anti-nukes just HATE this, and severely
critisize us for using such a deceptive concept.)

Would love to go into more detail, but have to get back to our DEADLY Human
Radiation Experiments (i.e., eating bananas.)

The same table in the CRC Handbook lists 3400 pCi/kg for white potatoes and
4450 pCi/kg for sweet potatoes - so you could carry through the same sort of
calculation for Reference Potatoes.  Interestingly, raw lima beans come in at
4640 pCi/kg, "dry, sweet" coconut comes in at 6400 pCi/kg, and raw spinach
(yum!) comes in at 6500 pCi/kg.

Considering the fact that the DOE has officially stated that "there is no safe
dose of radiation" my advice to you all is to stop eating immediately.

Oh yes!  Almost forgot.  Regarding K-40, go into your local grocery store, buy
some salt-substitute (there are two common brands, and the one in the white
and orange labeled container works best) spread some out on a table and check
it out with a GM survey instrument.  There it is folks, deadly radioactivity
in your grocery store!  

Yours for healthful diets . . .

Captain Internal Dosimetry
aka  Gary Mansfield, LLNL, (mansfield2@llnl.gov)


Neither Lawrence Livermore National Laboratory, the University of California,
nor the Department of Energy recommends eating bananas.