SURVEY: How do you get rid of ethidium bromide waste

Kieron Des kierondes at
Wed Apr 6 15:57:02 EST 1994

Hello netters:

     We're attempting to find out what the majority of people are doing with
ethidium bromide waste. Since ethidium bromide is a potent mutagen and is
moderately toxic (Waring, 1975), one would expect that there is a established
method of dealing with this substance. Various methods exist for degradation
(5% bleach solution, 5% hypophosphorous acid/0.5M sodium nitrite, etc.), and
for decontamination (Mutasorb, Amberlite resin, activated charcoal, etc.) Some
ways (like using bleach) have apparently fallen out of favor (Lunn & Sansone,
1987). I have reviewed the UIBio archives and find no consensus for the
"proper" method of disposing of ethidium bromide. We have examined various ways
to safely dispose of ethidium bromide generated in our own labs at Schleicher &

     For the sake of simplicity, I'd like to confine the discussion to EtBr
waste generated from staining agarose gels with dilute concentrations (0.5-1.0
ug/ml), since this generates the greatest volume of liquid waste (even though
some EtBr waste is at a higher concentration, such as that left over from CsCl
gradients). All answers are appreciated and, if requested, confidence will be
maintained. Later, I will post a summary of replies received once they are
compiled and analysed. To this end I've devised a series of "short answer"
questions (except #7). Please e-mail your responses to "kierondes at".
Here are the questions:

1. How many agarose gels do you typically run in a month?
 (round off your answer to the nearest 5 gels)

2. What percentage of these gels are stained with ethidium bromide?
 (round off your answer to the nearest 10 %)

Of these gels that are stained...

3. How do you stain with EtBr?  [A] During the run    [B] After the run

4. What concentration is your staining solution? ___ (ug EtBr/ml buffer)

5. What volume of solution remains to be discarded after EtBr staining?
 (round off your answer to the nearest 50 mL)

6. What do you do with the EtBr staining solution after you're finished?

   [A] Pour it down the sink.
   [B] decontaminate EtBr solution (Amberlite resin, etc),
       then pour it down the sink.
   [C] degrade EtBr solution (bleach solution, etc),
       then pour it down the sink.
   [D] Pour it into chemical waste container to accumulate
       for later disposal by institution.

   If your answer is [B] or [C], please list the method
   used for degradation or decontamination.

7. Why do you use this method of disposal? 

Thanks for your answers...
Kieron (Desmond) Walsh
Schleicher & Schuell
10 Optical Avenue, Keene, NH 03431
(603)352-3810 voice (603)357-3627 fax

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