Re: K-40 Concentrations in Soil

[Andrew Karam <karam.1@osu.edu>]

>Does anyone know where I can find typical K-40 concentrations in soil
>for central NJ?


You might check with the USGS or the NJ geological survey.  USGS put out
some aerial radiometric contour maps of Ohio with concentrations of ppm U
and Th and %K, all of which can be easily converted to pCi/gm or Bq/gm.  I
got my copies from teh Ohio Geological Survey.  A word of caution, however:
 these maps are pretty low-resolution and should be taken as guidelines and
not as "truth".  The real world is not nicely contoured.

K may be highly variable depending on land use and clay type.  Illite (a
common clay) can have nearly 50 pCi/gm of K-40 (K ions help to hold the
mineral together), but you rarely find pure illite or, for that matter,
pure clay of any sort.  Plus, underlying geology can influence soil K
concentration.  If the rocks are rich in K-rich minerals from granitic
rocks (micas, feldspars, etc.) the soil may contain more K than if the
underlying geology is basaltic.

Good luck!

Andy

The opinions expressed above are well-reasoned and insightful.  Needless to
say, they are not those of my employer. (with apologies to Michael Feldman)		

Andrew Karam, MS, CHP					(614) 292-1284 (phone)
The Ohio State University 					(614) 292-7002 (fax)
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