From: Harry Elston <harry.elston**At_Symbol_Here**GMAIL.COM>
Subject: Re: [DCHAS-L] EDTA in cleanup of aqueous radioisotope solution
Date: April 16, 2013 7:37:34 AM EDT
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: <2856a6a51c18051df9b20bc610782855**At_Symbol_Here**>

Injecting a little chemistry into the discussion:

EDTA is a great complexing agent - there is no argument there. However, its ability to complex metals is pH dependent by the metal you wish you complex. It's a case of "one size fits one" regardless of the marketing on the bottle or box.

I have cleaned up a number of radioactive spills in my career. None of them were fun because it goes everywhere, usually due to people not paying attention. The good news is that it's generally easy, though time consuming, to find the extent of the contamination. I can say that straight up, nothing beats phosphate-based detergents in the cleaning of rad spills. But phosphate detergents have fallen out of favor. Cleaning rad spills is a "lather-rinse-repeat" process in that it's wash-dry-monitor (and swipe for extremely low levels) and then you always need to ask "how clean is clean?" When do you stop?

Short half-lives are your friend when it comes to cleaning up a rad spill. Nothing says "clean" like decay. Advice varies on how long to wait. Most HP-types say 10 half lives, Experience has told me that 5-7 is usually satisfactory all but the most sensitive applications.. However you may not have the luxury in securing a space to wait that kind of time, especially if space is a premium.


On Mon, Apr 15, 2013 at 5:52 PM, Melissa Charlton-Smith <charltonsmith**At_Symbol_Here**> wrote:
When you asked I figured EDTA was used because it is a chelating-ligand
(because it binds to a metal or matalloid using more than one atom) but I
haven't found anything specific. I did find one paper (see below) which
mentions using it because it is an "aggressive chelate". Also found
several colleges/universities that include EDTA in their clean up
protocols but of course don't go into the chemistry of it. The
contaminated solution would go to the radiation safety personnel for
proper disposal....obviously couldn't go down the drain. I figure with
more digging than I did you could find some references.

The following is from: Radwaste Equipment Corrosion Associated with
To Chemical Cleaning Solution
John Freeman
Senior Treatment Systems Specialist
Wolf Creek Nuclear Operating Corp.
1550 Oxen Lane, N.E.
Burlington, Kansas 66839
Charles Jensen
Diversified Technologies Services, Inc.
2680 Westcott Boulevard
Knoxville, TN 37931

here is the link:

"Despite continual tweaking of formulation and application, EDTA-based
decontamination is a
well-established process. EDTA is an aggressive chelate that is very
effective for removing and
sequestering metals. While other chemicals are used to enhance metal
removal or transport, or
reestablishment of the passivated layer, EDTA remains the key


Mel Charlton-Smith
Chemical Hygiene Officer, Lab Coordinator, Lecturer
BS-CHO program
Department of Chemistry
WV Wesleyan College
Buckhannon, WV 26201


-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf
Of Buczynski, Michael
Sent: Monday, April 15, 2013 4:34 PM
Subject: Re: [DCHAS-L] EDTA in cleanup of aqueous radioisotope solution

EDTA is often added to a cleaning solution(laundry detergent) to help tie
up hard water metals and minerals were you to use a detergent without
EDTA for laundry in areas that have hard water (iron) clothes would look
dirty after the wash

-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf
Of Strode, Kyle
Sent: Monday, April 15, 2013 1:32 PM
Subject: [DCHAS-L] EDTA in cleanup of aqueous radioisotope solution

I'm teaching a unit on EDTA and its myriad uses in chemistry. I read
somewhere about why EDTA is often present in the cleaning solution used to
sponge up spills of low-level radioactive aqueous solutions. Two
1) How/why does EDTA enhance the cleanup from a chemical perspective?
I'm sure it has to do with the high Kf value for complexation, but I'd
love a confirmation.
2) What is done with the contaminated solution after sponging off the
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