Chemical & Laboratory Safety: Chemical Decontamination

Waste Mutagenic Dye Disposal

Mutagenic chemicals pose a significant long term threat to organic life due to their ability to modify an organism’s genetic material that may be passed along to future generations. 

Active mutagenic dye wastes may not be disposed of via the sanitary sewer or municipal trash without first being deactivated. Mutagenic dye wastes that do not fluoresce are considered to be inactive and acceptable for drain or trash disposal.

Options for Disposal by type of waste:

Dry Laboratory Wastes, including gloves and papers.

1. Materials that do not fluoresce under UV light may be disposed of directly in the trash
2. Deactivate the dye, dry the solids, and dispose via normal trash
3. Submit for BioHazardous Waste collection – identify the materials as “Chemo”
   

Gels

1. Gels that do not fluoresce under UV light may be disposed of directly in the trash
2. Deactivate the dye, dry the gel, and dispose via trash
3. Solubilize the gel, deactivate the dye and dispose via the sanitary sewer
4. Dry and submit to EH&S for collection as Contaminated Waste (request blue EH&S form)
   

Liquids (non-flammable)

1. Aqueous dye solutions that do not fluoresce under UV light may be disposed of directly to the sanitary sewer
2. Deactivate and dispose via the sanitary sewer
3. Absorb the mutagenic dye on filter media (activated carbon) and submit the media to EH&S for Hazardous Waste disposal Options for this method include:
   • Carbon ‘tea’ bags 
   • BondEX Maxi Ethidium Bromide Detoxification Cartridges
     

Liquids (flammable)

1. With the exception of contaminated labware, any mutagenic dye waste that contains a flammable liquid (such as butanol) should be submitted for Hazardous Waste disposal
   

Concentrated mutagenic dyes

1. Concentrated mutagenic dyes that are unusable may be submitted for Hazardous Waste disposal. This includes mutagenic dyes that are concentrated by absorption onto a filter media
   

Deactivation procedures:

Deactivation is managed by breaking the chemical bonds of the mutagenic dye. Within a laboratory setting, these bonds can be broken in several ways, including oxidization, and UV radiation. Deactivation of mutagenic dye waste materials must me incorporated as a last step in the research protocol. The methods described here oxidize the mutagen to remove the risk:

Household bleach:

The following is from Network News, Volume 8 No. 2, September 1994. Network News is a tri-annual publication of the ACS Department of Government Relations and Science Policy's Office of Legislative and Regulatory Programs. Margaret-Ann Armour is a professor in the Department of Chemistry at the University of Alberta

To convert ethidium bromide to the physiologically inactive product 2-carboxybenzophenone, stir a solution of 34 mg of ethidium bromide in 100 mL of water (at room temperature) with 300 mL of household bleach for 2 hours. When ethidium bromide solutions of this dilute concentration are used, the product solution does not show excess mutagenicity over standards in the Ames test.
Note: To extrapolate this method to various concentrations of ethidium bromide, you want to add ~ 10mL of household bleach for every mg of ethidium bromide.

You can check the extent of completion of this process with a Ultra-Violet (UV) lamp. EtBr glows bright orange under UV. If you see no orange fluorescence under the correct wavelength of UV in the detoxified material, then it has effectively been degraded

Hydrogen peroxide:

The following information is provided by the Office of Environmental Health & Safety at the University of Texas at Austin. The procedure below is adapted from, Destruction of Hazardous Chemicals in the Laboratory, 2nd Edition, by George Lunn and Eric B. Sansone.

1. Dilute the aqueous ethidium bromide solution (A) such that the total concentration of ethidium bromide does not exceed 0.4 mg/mL.
2. Add hydrogen peroxide (H2O2 ) solution to the ethidium bromide solution such that the resultant ethidium bromide solution has a 1% (vol/vol) concentration of H2O2 .
3. Bubble air with 300-400 ppm ozone (O3 ) as produced by an ozone generator through the reaction mixture at a rate of ca. 2 L/min for approximately 1 hour. The endpoint of the degradation process is indicated when the solution changes from red to faint yellow.
4. Check the mixture for completeness of destruction (B).
5. Quench residual ozone by adding enough aqueous sodium hydroxide (NaOH) to make the reaction mixture 1 M in NaOH.
6. Neutralize the subsequent reaction mixture with acid and discard via the sanitary sewer.