[logi_cal869]

It's a huge discrepancy; just seeking some help in narrowing down the actual figure along with a source (I've expended significant time already and only my exasperation has resulted in this request for help).

Thanks in advance.

[Gadsden1st]

The chair is against the wall.

[dp0622]

The answer is 7 :)

[onedoug]

My doc says radiation is cumulative.

[umgud]

Check these out. You can probably google NORM/TENORM Faq sheets too.

http://www.easysurf.cc/cnver24.htm

http://www.iem-inc.com/information/radioactivity-basics/basic-concepts

[waynesa98]

so is this a question about “new born Potassium-40” or the use as you will, as an alternative to radio carbon dating? it matters in terms of how the community looks at radioactivity.

[Leaning Right]

Many years ago, I was doing a research project that involved the force of sliding friction between a certain two materials in contact. So I went to various sources to look for the accepted data.

I was surprised to see how much the data varied on the exact same two materials. I suspect that was due to each researcher’s estimate of uncertainty. Different estimates of uncertainty would lead to different results. Perhaps that is what you are facing here.

[William Tell]

The lower number you are seeing may well be the specific activity of naturally occurring potassium which would only contain a small fraction of K-40.

[Mount Athos]

William tell gave you the answer. The much lower figure is the amount of radiation from k40 in “natural K”. K40 is only a tiny part of natural K.

The higher figure is for pure k40

[Mount Athos]

http://www.iem-inc.com/information/tools/specific-activities

[KarlInOhio]

The 818 pCi/g amount is for potassium with a natural distribution of stable and radioactive isotopes. The Argonne fact sheet says potassium-40 is 0.012% of natural potassium. Take 818 pCi/g and divide by 0.00012 and you get 6.8 uCi/gram of K-40, which is pretty close to the 7.1 uCi/g you already had, given the number of rounding errors and estimates that are running around.

[Enlightened1]

Hope this helps.

https://hazmap.nlm.nih.gov/category-details?id=1832&table=copytblagents

[Enlightened1]

This may help you too.

http://www.calrecycle.ca.gov/LEA/Conference/06Conf/Presentation/Day2/Radioactive/Greger/K40Food.pdf

[Enlightened1]

One more link,

http://www.philrutherford.com/Potassium-40_A.pdf

[smokingfrog]

Sorry. That information is need to know. ;)

[Hot Tabasco]

Others are the approximately- corresponding figures of 818 pCi/g, 30 kBq/kg (800 pCi/g, or 810 pCi/g, depending on which converter you use) and 8.54E-10, one of which is cited in the National Research Council book, Evaluation of Guidelines for Exposures to Technologically Enhanced Naturally Occurring Radioactive Materials...the basis of the EPA Guidelines for Exposure to Naturally Occurring Radioactive Materials.

Me and my buds were talking about that very subject last night in the bar after bowling.........I wish I could remember what they said since they may have had the answer you're looking for.