RE: Subj: Re: Cs-137 levels in South FL soils- ADDENDUM

["Neil, David M" <neildm@id.doe.gov>]

A factor that has not been mentioned in this discussion is that soils in
the Florida peninsula tend to be highly permeable - it's essentially a
giant sandbar built up on prehistoric reef structures. Combine that with
the heavy precipitation previously mentioned* and the rate of removal
from surface to deeper soil column or away to the ocean is enhanced.

The Panhandle area (Pensacola, Tallahassee, etc.) is more "normal" soil
characteristics.

*(No kidding - in summer the groundwater table is congruent with mean
local surface level. It rains every afternoon like clockwork in west
central Florida - right, Sandy?) 

Dave Neil 
neildm@id.doe.gov

On Wednesday, December 09, 1998 1:29 PM, RADPROJECT@aol.com
[SMTP:RADPROJECT@aol.com] wrote:
> In a message dated 12/8/98 4:59:39 PM Eastern Standard Time,
RADPROJECT
> writes:
> 
> <<   I don't have the references right at hand but Cs-137 in FL was,
if memory
> serves me right, at peak about 50-70 mCi/km^2. From this one can
derive an
> average soil concentration based on RG 1.109 assumptions of soil
depth,
> density, etc. It would work out to about 150 pCi/kg of soil, give or
take 50%
> on average. >>
> 
> My memory is hereby corrected. The above value quoted was for Sr-90
areal
> deposition, not Cs-137.  Since sending the above, I had a chance to
check a
> figure from a paper I delivered at an HPS Annual Meeting in Washington
in 1991
> ["Cs-137 in Woodash -Results of Nationwide Survey"] which contained a
figure
> on Sr-90 deposition isopleths in the US per various published
references.
> 
> The figure from an old AEC publication shows Sr-90 [not Cs-137]
deposition of
> 60 to 70 mCi/km^2 at peak. The Cs-137 areal deposition across FL would
thus
> have been about 100 mCi/km^2 at peak concentration in the late 1960s,
and
> about half that level at present based on decay. I haven't derived an
> estimated Cs-137 concentration, but it would probably be about 150 to
200
> pCi/kg of soil at present
> 
> Of note, one subsequent measurement of a woodash sample from
Gainesville, FL
> [my wife's sister's  fireplace - hardwood ash] not reported in my HPS
paper in
> 1991, had a Cs-137 concentration measured in 1994 at over 30,000
pCi/kg of
> woodash, the highest concentration of Cs-137 in woodash measured
anywhere in
> the U.S.  This one data point is quite intriguing. 
> 
> FL soil generally has very low potassium and therfore probably has a
very high
> transfer of Cs-137 from soil to plant since there is an inverse
relationship
> between potassium and plant uptake of Cs-137 since plants have to
struggle to
> get enough K in low K soils and tend to suck up the Cs-137 which comes
down in
> fallout as carrier free Cs. In the 1960s, FL also reported some of the
highest
> Cs-137 concentrations in milk of any area of the US despite the
fallout there
> not being unusually high.
> 
> Reg. Guide 1.109 provides a value for the transfer factor from soil to
plant
> [the so-called Biv value : pCi/kg-plant/pCi.kg-soil) of 0.01]. Woodash
> typically has an ash fraction of about 0.5 to 1% or about 100 to 200
parts
> wood to one part ash. 30,000 pCi of Cs-137 per kg of ash thereby
implies
> [assuming no Cs loss on combustion!] a plant concentration of 150 to
300
> pCi/kg. However, the soil concentration of Cs-137 in FL is likely to
be
> about150 pCi/kg. Thus the Biv for FL is about 1.0 to 2.0 not 0.01!!
Thus any
> dose calculations of terrestrial food pathways done for any unit
Cs-137
> deposition in FL using a RG 1.109 transfer factor of 0.01 is likely to
be low
> by a factor of from 100 to 200. 
> 
> This point should receive intensive study but it has never been
investigated.
> I tried to get the EPA a few years ago to fund an investigation of
Cs-137 in
> wood ash after my initial survey and paper at the HPS meeting.
However, one of
> the EPA reviewers discounted my proposal saying they didn't think
there would
> be any Cs-137 in trees despite measurements having been reported to me
from
> about 15 different institutions and facilities including the Princton
Plasma
> Physics Lab, various NBS traceable measurements at various utilities,
etc.
> 
> I guess the old saying is true. "Don't try and teach a pig to sing.
You only
> waste your time and upset the pig"
> 
> 
> Stewart Farber, MS Public Health
> Public Health Sciences
> Phone/FAX: 401 727-4947 
> Email: radproject@usa.net
>
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