To follow-up on the Larry/Craig thread, our preference is to have known ethidium bromide waste pulled into our hazardous waste stream because our down-stream non-hazardous waste processor will not accept mutagenic waste and has explicitly called out EtBr.  This also would not have bearing on the disposal of the liquid wastes - though these too we encourage collection as hazardous waste (but do offer guidance on addressing via benchtop treatment).

 

With regards to the treatment methods, the older filter/column based systems encourage re-use and typically end up still in use well-after their charcoal/resins have been saturated, resulting in increased handling of the EtBr solutions with minimal attenuation of the EtBr.  The single-use destaining bags mentioned in the UCD document do have a much greater chance of not being mis-used and do work well.  These absorption methods seem to be significantly preferred over the chemical method proposed by Lunn and Sansone.  Though this method suffers from a tendency for users to try and substitute phosphoric acid, but when used correctly works well and is the go-to for surface decontamination.

 

It seems like there should also be the ominous reminder about not using hypochlorite to inactivate EtBr as the resultant might be more mutagenic. 

 

 

 

Forwarded from Craig Barney. Environmental programs manager at Stanford EHS 

From: "Craig A. Barney" <cbarney**At_Symbol_Here**stanford.edu>
Date: August 10, 2018 at 10:23:20 AM PDT
To: Lawrence M Gibbs <lgibbs**At_Symbol_Here**stanford.edu>
Subject: Re: [DCHAS-L] Dilute Ethidium Bromide Disposal in California

Our limit is 0.4% by weight based on the California Toxicity characteristic 

The controversy hinges on not the toxicity but mutagenic property 

Craig

 

Sent from my toaster

On Aug 10, 2018, at 10:07 AM, Lawrence M Gibbs <lgibbs**At_Symbol_Here**stanford.edu> wrote:

Did'nt stanford do some testing on this many moons ago? 

Larry

Begin forwarded message:

From: Penny Manisco <pmanisco**At_Symbol_Here**G.HMC.EDU>
Date: August 9, 2018 at 4:37:42 PM PDT
To: <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Subject: [DCHAS-L] Dilute Ethidium Bromide Disposal in California
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>

Hello All,

 

There seems to be varying opinion on how to dispose of very dilute solutions of ethidium bromide. The concentration in question is 0.5 micrograms/ml of buffer. By hazardous waste definition, this  would not be considered a hazardous waste, but I believe some of our California universities and colleges recommend filtration of the ethidium bromide before disposal at any concentration.

 

Any guidance would be very much appreciated.

 

Sincerely,

--

Penny Manisco,
Chemical Hygiene Officer
Harvey Mudd College

(909)6074217

--- For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchas

--- For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchas