Re: estimates of human-human irradiations

["M. Woo" <m-woo@uiuc.edu>]

Kimberlee Kearfott wrote:

> I don't want to start an instoppable thread-- but has anybody
> computed how much irradiation we get from standing by others, due to
> our natural concentrations of radionuclides?  Any other similar
> comparisons?

Rick Strickert put together an amusing analysis of K-40 exposure that he
posted to the list back in 1995.  Here is the excerpt from the archives:

====cut====
Recent RADSAFE emails suggest a considerable concern about radiation
exposure from bananas.  While I limit my banana intake to servings of
banana (brazil?) nut bread, there is a more serious source of K-40
radiation poisoning.

According to UNSCEAR (1988) the annual effective dose equivalent from
the body's K-40 is an estimated 180 uSv (18 mrem).  Now, in the case
where two people share the same bed for 8 hrs/day, and assuming a
geometry factor of 0.16 (this is probably subject to considerable
variation; I don't want to discuss it), then each person would receive
an additional annual radiation dose of approximately 10 uSv (1 mrem)
from the other person's K-40.  This does not take into account any
backscatter from a slab floor (a NORM problem itself!).

There are at least 60 million married couples in the U.S. that I will
assume sleep together (you can supplement the number if you wish).
This results in a U.S population exposure of at least 1200 PYSv
(120,000 man-rem per year). (PC hawks - I'm using the dictionary's
first definition of 'man'.)

Using 8,000 man-rems per lethal cancer (Wilson and Crouch, Science 236,
1987, pp. 267-270), the sleeping together radiation dose equivalent
(STRDE) results in an estimated average of 15 deaths in the U.S per
year.                                      ^^^^^^^^^

However, I don't think a lead-lined teddy will ever become popular.
====cut====

-- 
Melissa Woo, Health Physicist <mailto:m-woo@uiuc.edu>
Div. of Environmental Health & Safety
101 S. Gregory St., MC-225, Urbana, IL 61801
ph 217.244.7233 fax 217.244.6594 <http://www.uiuc.edu/ph/www/m-woo/>
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