[Histonet] procedure for disposal of DAB waste from Ventana Stainer

[Lynette Pavelich]

Tiffany,
I am quoting an exerpt from Dapson & Dapson's (Anatech) Hazardous
Materials in the Histopathology Laboratory (3rd edition of Regulations
Risks Handling and Disposal):
"The chromogens AEC and DAB likewise have been the subject of much
misinformation.  DAB is probably carcinogenic, based on its relationship
to the benzidine family (all members of which that have been studied
have been shown to be carcinogenic).  AEC has been suggested as a safer
alternative, but toxicological literature has neither supported nor
refuted that claim to date.  While there is no detoxification process
for AEC, two exist for DAB.  Do not use sodium hypochlorite (household
bleach) as a detoxifying agent for DAB, despite recommendations to the
contrary in some product literature, because the reaction products
remain mutagenic.  
Lunn and Sansone present two methods for detoxifying DAB.  One involves
the use of acidified potassium permanganate to detoxify the chromogen,
then sodium ascorbate and sodium bicarbonate, respectively to decolorize
and nutralize the mixture prior to drain disposal.  This method works
for the solutions of DAB as well as the colored precipitate that forms
when DAB is reacted with horseradish peroxidase (the latter is mutagenic
like DAB)."

Procedure:
1.  Prepare the following aqueous stock solutions
     a.  0.2 M potassium permanganate (31.6 g KMnO4/liter)
     b.  2.0 M sulfuric acid (112 ml concentrated aced/liter)
2.  Dilute the DAB solution if necessary so that its concentration does
not exceed 0.9 mg/ml.
3.  For each 10 ml of DAB solution, add:
     a.  5 ml 0.2 M potassium permanganate
     b.  5 ml 2.0 M sulfuric acid
4.  Allow mixture to stand for at least 10 hours.  It is now
non-mutagenic.
5.  Decolorize the mixture with ascorbic acid (add powder until color
disappears).
6.  Nutralize the decolorized mixture with sodium bicarbonate (test with
pH meter, pH paper or dipsticks).
7.  Discard the solution down the drain provided that local wastewater
authorities have given their approval.

Lynette Pavelich, HT(ASCP)
Histology Supervisor
Hurley Medical Center
One Hurley Plaza
Flint, MI  48503

ph:  810-257-9948
fax:  810-762-7082
>>> "Price, Tiffany" <Tiffany.Price <@t> thomaswv.org> 03/07/07 11:08 AM >>>
Does anyone have a procedure for disposal of DAB waste? I have a
procedure that uses magnesium permanganate, but I understand that you
can also use bleach.
Thanks for any information-
Tiffany
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