RE: Welcome to California(

["Wes Van Pelt" <wesvanpelt@ATT.NET>]

Emil and all,



Yes, I have tried to correlate radioactive concentration of TENORM in soil

with gamma levels at 1 meter above the surface. The several hundred

boreholes showed elevated TENORM concentrations down to about 3-6 feet or

occasionally deeper. The correlation is very scattered due in great part to

the variability of the radioactive concentration, both vertically and

horizontally.



But, you can probably get 100-300 aboveground gamma readings for the cost of

each borehole with lab analysis of 3-5 soil samples at depth.



Regards,

Wes



Wesley R. Van Pelt, PhD, CIH, CHP

Wesley R. Van Pelt Associates, Inc.

Consulting in Radiation Safety and Environmental Radioactivity.

http://home.att.net/~wesvanpelt/Radiation.html

mailto:wesvanpelt@att.net



-----Original Message-----

From: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu]On Behalf Of Kerimbaev

Sent: Sunday, June 02, 2002 11:33 PM

To: radsafe@list.vanderbilt.edu

Cc: Wes Van Pelt

Subject: RE: Welcome to California(



Wes,



Have you tried?:



1. To estimate activity distribution by driling

just a "few" holes.



2. To establish correlation Depth vs Absorption

(including self absorption) in the soil /

Shielding from the soil.



3.It could safe some money....



I know it can be done "easily" in the laboratory

set up, I was wondering if a some one has tried

that for the large areas monitoring....



Emil.





Wes wrote:



Carl,



The first thing to do is state in detail the

question you wish to answer by

doing a gamma scan over a large area. By your

last sentence, it appears you

want to measure the extent of residual

contamination that produces a cancer

risk of 1 in 1,000,000. This requires dose

modeling, including ingestion of

vegetables grown on the land, drinking water from



wells, drinking cow's

milk, breathing airborne dust, as well as direct

gamma exposure. But this is

quite easy using commonly available environmental



dose codes.



Then just equate radiation dose to cancer risk

using the Linear

Non-Threshold theory. (Please, no flames.)



The big problem, as I see it, is determining the

depth over which the

residual contamination is spread.  For example,

does it go down 4 inches of

4 feet? And how is it distributed by depth? The

only way I know to determine

this is to drill holes and analyze the core

samples for radionuclide

concentration and also doing down-hole gamma

readings. This gets expensive

and requires a lot of drill holes.



Regards,

Wes







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