[ RadSafe ] Reporter's question about lower limits of detection Congratulations

[parthasarathy k s]

Dear Mr Matthew Wald,

Congratulations to you (from India) for the query you posted in this list. I am sure there will be an avalanche of responses from specialists. I read your articles in the NYT and have been impressed by them. 


 You may realize how complicated and difficult it will be for a journalist to arrive at a satisfactory answer to the query from the very scientific answers you receive. Probably, the NYT gives you the freedom to exceed the "700 words" limit. That is the limit a leading multi-edition newspaper such as The Hindu allows. This paper publishes a very popular weekly science & technology section of one page.


I hope that your interaction with the specialist group may lead to improved communication. Your "lurker" role may prove to be very beneficial to the NYT readers. In the meanwhile, I shall eagerly wait for your article. 

with best wishes
Parthasarathy



________________________________
From: "Wald, Matthew" <mattwald at nytimes.com>
To: "'radsafe at agni.phys.iit.edu'" <radsafe at agni.phys.iit.edu>
Sent: Friday, 5 August 2011, 21:00
Subject: [ RadSafe ] Reporter's question about lower limits of detection

I have been a "lurker" on this list for a couple of years, and I write intermittently about nuclear power. 
Could someone who is expert on this subject please help me with a radiation measurement question?
What is the lower limit of detection for strontium-90 in fish ?
Background: 
The Vermont Department of Health samples fish from the Connecticut River. It recently reported finding strontium-90 in some samples, slightly above what it said was the lower limit of detection, 47 pCi/kg. See: http://healthvermont.gov/enviro/rad/yankee/tritium.aspx

A website called Vermont Digger, http://vtdigger.org/2011/08/02/vermont-yankee-4/, reported on the result.  But Vermont Digger also says that New York measured 8 pCi/kg. 

http://vtdigger.org/2011/08/04/shumlin-vermont-yankee-not-necessarily-source-of-strontium-90-in-fish/

The underlying issue is whether the strontium came from the Vermont Yankee reactor, in Vernon, near the Massachusetts border, which had a leak from an underground pipe, or whether it is from fallout or some other source.  But I have another question. 
What is the lower limit of detection? 8 picocuries per kg? 47? Some other number? And what determines the lower limit? 
I would appreciate any explanation. 

Thank you. 
--- Matt Wald


Matthew L. Wald
Washington Bureau
The New York Times
1627 Eye St NW, Suite 700
Washington, DC 20006
202-862-0363
cell: 202-997-5854
fax: 202-318-0057

http://www.nytimes.com/info/nuclear-energy/
twitter: mattwaldnyt

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

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