Re: Waterborne radon

[Schoenhofer <schoenho@via.at>]

At 11:52 03.12.1996 -0600, you wrote:
>          The general rule of thumb for the contribution of waterborne
>          radon to indoor radon is 10,000 pCi/L of radon in water
>          contributes about 1 pCi/L of indoor radon in air.
>          Activities like showering or dishwashing may decrease
>          the water to air transfer ratio for short periods,
>          especially in poorly ventilated areas of the home, such as
>          bathrooms.
>
>          In may be of interest to note that in Iowa the highest
>          waterborne radon concentrations are attributed to radium
>          which becomes adsorbed onto iron pipe scale in the water
>          distribution systems.  I have seen radon concentrations of
>          10 pCi/L in water leaving the treatment
>          plant and by the time the water reaches the home the
>          waterborne radon concentration is 10,000 pCi/L.
>
>         Bill Field
>
>
>        
>        R. William Field, Ph.D.
>        University of Iowa
>        bill-field@uiowa.edu
>
>-------------------------------------------------------

Bill,

The factor of 1: 10 000 is very well known and we use it in our calculation.
Howard Prichard has done extensive work on that.

I think that also other radsafers would be interested in more detailed
information about the effect of radium adsorbed on iron pipes. 10 000 pCi/l
of radon in water is something which cannot be neglected. What is the
concentration of Ra-226 in this water? Taking all the disequilibrium into
account there must be incredible concentrations of Ra-226 present both in
the water and the pipes to give rise to such deposits and to such
concentrations of Rn-222. 

Franz
Schoenhofer
Habichergasse 31/7
A-1160 WIEN
AUSTRIA/EUROPE
Tel./Fax:	+43-1-4955308
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e-mail:		schoenho@via.at