Re: Potassium 40 variation in soil

["Leon E Brown" <lebrown@cmsenergy.com>]

Bjorn,

I think you can find the information you are looking for in Appendix O of EPA
402-R-96-011 A, "Technical Support Document For The Development Of Radionuclide
Cleanup Levels For Soil, Review Draft," September 1994.  I don't recall the
specific address, but I do know that I downloaded my electronic copy from the
EPA web site.  It lists K-40 variability as 3 - 20 pCi/g (111 - 740 Bq/kg) with
a typical concentration of 10 pCi/g (370 Bq/kg).  For Th-232, it lists 0.10 -
3.4 pCi/g (3.7 - 123.8 Bq/kg) with a typical concentration of 0.87 pCi/g (32.19
Bq/kg) and for U-238, it lists 0.12 - 3.8 pCi/g (4.44 - 140.6 Bq/kg) with a
typical concentration of 0.96 pCi/g (35.52 Bq/kg).

There is also a good discussion of the variability of background in Appendix A
to NRC NUREG-1496, "Generic Environmental Impact Statement in Support of
Rulemaking on Radiological Criteria for Decommissioning of NRC-Licensed Nuclear
Facilities."  I don't think that NUREG-1496 is available on the web, however.

Leon E. Brown, CHP
Senior Consultant
Big Rock Point Restoration Project
(231) 547-8419
lebrown@cmsenergy.com


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