Dear Janice,

Diaminobenzidine, the most problematic byproduct of IHC staining, is a
documented mutagen iand probably carcinogenic based on its relationship to
the benzidine family (all member of which have been studied have been shown
to be carcinogenic)i as documented by Dapson & Dapson, Hazardous Materials
in the Histopathology Laboratory, 1995.  Moreover, the National Toxicology
program has suggested that the family of benzidine based dyes be listed as
known human carcinogens.  1998 Report on Carcinogens,
http://ntp-server.niehs.nih.gov/.

Dapson and Dapson go on to say in their book that ithere are two acceptable
methods for detoxification of DAB according to Lunn and Sansone.  One
method involves the use of acidified potassium permanganate to detoxify the
chromagen, then sodium ascorbate and sodium bicarbonate, respectively to
decolorize and neutralize the mixture prior to drain disposal.  This method
also works for DAB solutions as well as the colored precipitate that forms
when DAB is reacted with horseradish peroxidase (the latter is mutagenic
like DAB).  The second method utilizes the histochemical reaction with
horseradish peroxidase.  The advantage of the latter is that is
concentrates the chromagen; the disadvantages are expense and the need to
perform the first detoxification method on the precipitate.  These methods
can be expensive, in both technician time and chemicals.  Using chlorine
bleach (or sodium hypochlorite) is neither chemically sensible nor
effective.i

We offer an alternative means to extract and contain DAB easily and safely
using our new DabOut LVS system.  Hazardous waste from the staining
instrument is collected in a user-supplied collection carboy connected to
the staineris waste line.  The DabOut LVS system pumps the DAB material
from the waste carboy through the cartridge.  The tube with liquid emerging
from the cartridge can either be fed into an effluent collection container
for later drain disposal or put directly down the drain.  This system
removes DAB to below the detectable limit of 0.1ppm.

If you would like to try the system, please contact me toll-free at
888-296-2423 in North America.  I can also be reach via e-mail at
dunlap@naiadtech.com.

Kelly Dunlap
Product Manager
Naiad Technologies, Inc.
888-296-2423
503-274-4407


"Koutney, Janice" wrote:

> Good Morning All!
>
> We're having a problem coming to a meeting of the minds here as to what
> should be done with the DAB waste retrieved from our DAKO Autostainer.
> I was wondering what everyone out there does with theirs.
> Thanks for your input.
>
> Janice Koutny
> Cytometry Associates
> Brentwood, TN