Elevated gross alpha background concentrations -Reply

[Charles Willis <CAW@nrc.gov>]

Elizabeth,

A change of the magnitude you are seeing could be the result of a change in the
weather.  How far back do your records go?  History might be helpful.  

Of course coal fired plants release radium and radon (see the UNSCEAR reports). 
The likelihood of such a plant having the same effect on your site and a control
point 12 miles away seems small but not zero.  Only measurements could tell.

Charlie Willis
caw@nrc.gov
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