More cesium than k40 in California soil

Submitted by Anonymous on Mon, 2011-10-17 10:48

This is what my lab results indicate . I bring this up because there has been so much talk that there's more natural radiation than man made in our soil .well in my testing this case this does not appear true. I would hope brawm would comment on this fact. Would this be an anomaly ?My results are posted in collective sample update.

‹ Request for cumulative data compared to Chernobyl Soil layer update (10/18/2011) ›

Scientific notation... K-40 is much greater

Submitted by bandstra on Mon, 2011-10-17 11:33.
Are you referring to these results: Coastal valley in northern California results above mda? Here are the results from that posting. There are a couple of symbols that have been copied down that I do not understand ("-o" and "-1" in the middle of the numbers — could you clarify what those mean?). Also, was there a minimum detectable concentration given? So as best as I can tell, this is what those results are:
IsotopeActivity (pCi/g)
Cs-1372.8460e-02
Cs-1341.686e-02
K-401.6039e+00
The "e" represents scientific notation, so the number should be multiplied by 10 to the power after the "e". In this case here's what the numbers are rewritten without scientific notation. I have added a column of activity concentration in Bq/kg, which are the units we use, for comparison:
IsotopeActivity (pCi/g)Activity (Bq/kg)
Cs-1370.0284601.0530
Cs-1340.016860.6238
K-401.603959.34
So I hope you can see that the cesium levels are about 1/60th of the K-40 level. The cesium levels are consistent with some of our soil measurements. The K-40 in that sample is actually low — we usually find 200–500 Bq/kg. Let me know if this clarifies everything. Mark [BRAWM Team Member]

-0 and -1 in middle of numbers was error on my part

Submitted by Anonymous (not verified) on Tue, 2011-10-18 10:43.

Mark thanks for response And conversion to bq/ kg .The mda / Mdc were listed as follows
Cesium 137---1.371E-02
Cesium 134---1.361E-02
K40---1.272E-01

Mark as far as total activity in the 40.2- 2034.8 Kev range this sample registered 4.232E+01 how does this compre to other locations in ca your team has tested .also is this Kev range similar to your capabilitys? Thanks for the help understanding results.

Total activity is low

Submitted by bandstra on Thu, 2011-10-27 13:27.

That total activity figure (42.32 Bq/kg) is too low for soil. The potassium-40 activity alone was given as 59.34 Bq/kg.

For a breakdown of the typical soil activities that we find, please see this posting: http://www.nuc.berkeley.edu/node/4566#comment-19067

We have a similar range for detection — about 50 keV to 2614 keV. We in principle could look higher than 2614 keV but there are typically no lines there and our efficiency becomes very small.

Mark [BRAWM Team Member]

Total together?

Submitted by Anonymous (not verified) on Thu, 2011-10-27 21:30.

That's intresting will investigate. as lab result summary is
total activity 4.232E+01pci/g
Total decayed activity 6.5400894E+01pci/g

Sorry, I used the wrong

Submitted by bandstra on Fri, 2011-10-28 12:44.

Sorry, I used the wrong units. I was thinking in Bq/kg but that quantity is pCi/g. I think the numbers are consistent.

Mark [BRAWM Team Member]