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RE: News on BNL Deer -Factors at play?



Hello Bill-
 
Sorry, but I have to pull you back from this precipice to maintain a clear conscience.  I know that you have an appreciation of the large variability of values obtained with low statistical significance. A large deviation of a single value in a set of measurements with low statistical significance is a far stretch from a programmatic failure on the part of BNL (although it does not rule it out). But apart from a potentially unending discussion on LLD and measurements uncertainty, a simple anecdotal recollection may serve as one example of an extensive set of possible ways in which this episode may not be even related to BNL other than proximity.
 
In the first round of personnel baseline evaluations immediately following the commissioning of a new whole body counter at a certain South Georgia nuclear power plant (about 30 years ago - prior to startup), the typical stream of spectra, devoid of any prominence other than a K-40 peak varying with physical parameters of the individual, was interrupted by the clear presence of Cs-137 in one burly construction worker. Measurements continued while sources of local contamination were sought, until a second such occurence in another worker was observed, whom after some investigation proved to be a hunting buddy of the first positive subject. While the levels of internal contamination were far less than those that would represent any significant dose, they were many times higher than the lower limit of detection achieved for the vast population of subjects whose diet did not contain a significant proportion of wild game.
 
While deer are not thought to maintain the level of contemplation that opens such a wide diversity of options to humans, anyone who has pursued the habits of these intriguing animals for whatever reason can ascribe enigmatic characteristics to particular members of a population. It would not be the least stretch to expect that one or more animals may happen to encounter or develop a preference for a particular plant or mineral source that may convey more cesium (present from  fallout) either due to the form in which it is bound, an collection effect such as surface area or characteristics, or the biokinetics of the distribution of the cesium in the plant.
 
Please do not hang BNL on small statistics or biological flukes for something not even shown to be related to their operations!
 
Bob Hearn
rah@america.net
 
 From: owner-radsafe@list.vanderbilt.edu [mailto:owner-radsafe@list.vanderbilt.edu]On Behalf Of William V Lipton
Sent: Tuesday, February 19, 2002 3:50 PM
To: SAFarberMSPH@CS.COM
Cc: Cehn@AOL.COM; radsafe@list.vanderbilt.edu
Subject: Re: News on BNL Deer -Factors at play?

You seem to be addressing the variability of Cs-137 with location.  The issue, here, is variability over time at a single location.  The data, subject to verification, indicate a significant spike in the Cs-137 found in an animal potentially impacted by BNL.  The news article indicates that this is probably due to contaminated soil at BNL.  At the very least, this is a working hypothesis, subject to further investigation.

If this is confirmed as due to BNL operations, it represents a significant programmatic failure, regardless of dose.

The opinions expressed are strictly mine.
It's not about dose, it's about trust.
Let's look at the real problem for a change.

Bill Lipton
liptonw@dteenergy.com

SAFarberMSPH@CS.COM wrote:

Radsafe:
Some input from Brookhaven on the units and isotopic measurements would be of interest. However, it is most likely the activity measured is Cs-137 and the units are probably pCi/g. If so the dose consequences are rather small.

Of note:
The variability in sampling residual weapons test fallout in animals around a nuclear facility can be quite large. The area around Brookhaven has very sandy soil as does most of Long Island which leads to very high transfer factors [Biv in RG 1.109] from soil to plant per unit deposition vs. that typically assumed.  This Biv factor can vary from the typically assumed 0.01 [one part Cs in plant to 100 parts in soil]  to a hundred times higher in very sandy soils or soils very low in potassium where the plant like grass [or tree] will try and suck up the potassium it needs to grow and take up Cs instead [chemical cogener] in its attempt to get what it needs.

If the particular young deer reported upon here had been  browsing on plants from an area particularly low in potassium in soil, the plants and tree shoots [and bark] which deer eat would be higher than other areas of soil which was more organic and higher in K. Bark on trees contains the highest percentage of minerals [and residual Cs-137 per unit weight] of any component of a tree. In winter, trees store what minerals they can before dropping their leaves and some ends up in the bark. Having lived in Vermont for many years, I've observed deer stripping the bark off trees in winter for some minerals and food value. This would obviously lead to some variability of intake of Cs-137 during the year depending on locale.

As I've mentioned in previous posts to Radsafe when I coordinated a nationwide survey of Cs-137 in woodash from domestic fireplaces about 10 years ago, the Cs-137 activity varied from about 200 pCi/kg wood ash in southern California to 35,000 pCi/kg in northern Florida [Gainesville - no where close to a nuclear facility]. Even in a single state like Vermont with very even fallout deposition, the Cs-137 activity varied from about 20,000  pCi/kg of ash in northern Vermont [Warren, VT area] to about one-tenth as much [roughly 2,000 pCi/kg ash]  in a sample of ash in sourthern Vermont from hardwoods collected around Vernon, VT [site of Vermont Yankee]. This data obviously shows that Vermont Yankee is sucking up Cs-137 from the environment! If the ten fold higher value in ash from trees around Vermont Yankee Nuclear Power Station had measured near a nuclear facility, I'm sure folks like our resident anti-nuke Norm would be issuing press releases non-stop. The Tooth Fa! ! iry Project and Alec Baldwin and Christie Brinkley would be testifying before Congress trying to stop Yucca!

In any case, while this one sampling of a deer on Long Island may help understand some of the pathways of Cs-137 [almost certainly] movement in a sandy soiled, coastal environment like Long Island [relevant to Cape Cod, and much of Florida] it is unlikely to be indicative of any health concerns.

Stewart Farber
Consulting Public Health Scientist
[203] 367-0791
email: SAFarberMSPH@cs.com
======================
In a message dated 2/19/02 10:10:29 AM Pacific Standard Time, Cehn@AOL.COM writes: [excerpt from "news" report]
 
 

After several radiation tests on the deer, lab scientists found it contained 21 picocuries of radioactive material. A picocurie is a unit used to measure radioactivity.

Last year, deer collected around the lab averaged 1.64 picocuries, although one registered 11 picocuries, Green said.