Hot playground? -Reply

[Craig D Brown <CBROWN@envc.sandia.gov>]

Based on some real quick calculations and the following
assumptions I get an EDE of 0.6 mrem/yr (in excess of
background) to the onsite child.  Included is direct gamma,
inhalation (radon and others), and soil ingestion.  As stated,
these were really quick and only my opinions/assumptions.

-Child spends 1 hour/day, 180 days per year outside on the
playground
-Playground area is 10,000 m^2, uniformly contaminated to
15 cm below ground surface
-2 pCi/g  of Ra-226 and 21 pCi/g (each) of U-234 and U-238
(assumed numbers in excess of background)
-Child ingests 13.5 grams of contaminated soil per year
(based on EPA recommendation of 0.1 g/day, assume 3/4
of that received onsite)
-Exposure duration is 8 years  


cbrown@envc.sandia.gov