RE: I-131 Volatility Ratio

["Wesley" <wesvanpelt@att.net>]

Jon,



Of course it depends greatly on the chemical and physical circumstances.

However, I can give you one single quantitative example of how volatile

radioiodine is.



Some years ago I purposely generated an I-125 iodine vapor in a chemical

fume hood to test the efficiency of the charcoal filters in the exhaust

system. I put 5 microcuries of I-125 as NaI in 10 microliters of aqueous

solution in a small vial and added some stable carrier iodine. I then added

acid and warmed the open vial with a heat gun for about 15 minutes. In this

experiment, I attempted to volatilize all of the radioiodine. Based on vague

chemistry and radiation safety folklore I had expected that essentially all

of the radioiodine would volatilize. Using a gamma scintillation survey

meter to measure gamma dose rate at a fixed distance from the vial, I found

that 80 percent of the activity volatilized and 20 percent remained in the

vial.



Best regards,

Wes

Wesley R. Van Pelt, PhD, CIH, CHP

Wesley R. Van Pelt Associates, Inc.

 



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

From: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu] On Behalf Of Aro, Jon

Sent: Wednesday, January 26, 2005 5:25 PM

To: radsafe

Subject: I-131 Volatility Ratio



Hi All, 



I am looking for the volatility ratio of I-131, essentially the amount

of airborne activity one would expect from a known activity of I-131.

I am trying to estimate the exposure an individual would receive as a

result of radioactive materials being vented through a fume hood.  The

only isotope that we use where airborne contamination is of concern is

I-131, as it can be volatile.  After searching Google & hps.org I have

found nothing.  The "ask the expert" section mentioned that there is no

"one-size-fits-all" approach to this problem. 



Has anyone come across this problem before?   What ratios did you

find/come up with?



Thanks in advance,



Jon Aro

Ottawa Hospital







************************************************************************

You are currently subscribed to the Radsafe mailing list. To

unsubscribe, send an e-mail to Majordomo@list.vanderbilt.edu  Put the

text "unsubscribe radsafe" (no quote marks) in the body of the e-mail,

with no subject line. You can view the Radsafe archives at

http://www.vanderbilt.edu/radsafe/