Re: Household radioactive materials?

["Dale E. Boyce" <dale@radpro.uchicago.edu>]

In addition to the salt substitute and fiesta wear which tend to
get peoples attention and all the other common items already mentioned
many types of green "depression" glass are measurably radioactive.
I learned about this one only because I had to do an "emergency"
survey of some hot patient waste when I needed to be headed for
the airport.  As a result, a survey instrument got to go home
to visit my mother.  After showing my mom the 2 mRem / hr reading
from her orange (they call it red in catalogs) fiesta wear, she insisted
that I survey all of her antique stuff.  Some of the green glass was
a couple of tenths of a mrem/hr. (Actually, the readings should be
in cpm since most of it is beta).

I have an antique Rolex with a radium dial that reads 20 mrem / hr
at the crystal and less than 1 mrem / hr at the back.  I learned about
that when I set off a portal alarm one day at Los Alamos. I believe
for awhile they made Sr90 dials that were even hotter.  Some old
alarm clocks supposedly had quite a bit of activity, although I
have never measured one.  Don't forget smoke detectors!  They usually
have about 1 microcurie of Am-241, and some have up to 5 microcuries.  

Many types of glazed tiles are hot.  During some FUSRAP work here,
the contractors got very excited when they discovered alpha
contamination on the roof of one of our buildings.  Turns out,
after a nasty fall by the foreman and many broken tiles, it was
in the glaze on the terracotta colored tiles.  In what used to
be the labor and delivery floor of one of our hospitals, the
hallway is lined with a dark green glazed tile (now painted over).
We get readings of 2,500 cpm with a thin NaI detector (background
is about 200 cpm) and about 0.1 mrem per hour.

Welding rods, while not a typical household item, may contain
thorium.  Exit signs can have multiple curies of H-3, but again are
not typical household items.

Dale Boyce
dale@radpro.uchicago.edu