Worse than bananas

["rick strickert" <rick_strickert@pc.radian.com>]

    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.



Richard G. Strickert, Ph.D.          |     "Absolutum obsoletum -
Radian Corporation, Austin, TX       |  if it works, it's out of date."
Internet:rick_strickert@radian.com   |            - Stafford Beer
 ---> "All written IMHO." <---       |