Laboratory Services

The University of Mississippi

Ethidium Bromide (EtBr) Disposal

Ethidium bromide (EtBr) is a strong mutagen and a possible carcinogen or teratogen.

When you work with EtBr, you must wear a lab coat, chemical splash goggles, and nitrile gloves.

Always use caution when using an ultraviolet light while working with EtBr.

Always use a chemical fume hood during processes that can generate EtBr dusts or mists.

Ethidium Bromide, unused

  • Collect for disposal by Health & Safety

Aqueous solutions containing < 5 mg/L EtBr

  • Dispose to the sanitary sewer.

Aqueous solutions containing > 5 mg/L EtBr

If the solutions contain no other Hazardous Materials (organics, salts, metals, etc.)

  • For every 100 ml of EtBr solution add
  • 20 ml 5% hypophosphorous acid solution and
  • 12 ml 0.5 M sodium nitrite solution.
  • Stir mixture and let sit for 20 hours
  • Neutralize with sodium bicarbonate, then dispose into the sanitary sewer (sink).

Solvents containing EtBr

  • Collect for disposal by Health & Safety.

Radioactive EtBr solutions

  • Collect for disposal by Health & Safety, Radiation Safety

Gels containing EtBr

  • Break up Gels
  • Chemically degrade as noted above
  • Dispose to the sanitary sewer, or,
  • Dry Gels and Collect for disposal by Health & Safety

Materials (gloves, pipettes, tips, etc.) used with EtBr

  • Place in secure container (taped box with plastic bag liner) and place the container directly into a dumpster.

Commercially available products, like the “Destaining Bags” produced by AMRESCO provide an alternative method of treatment for solutions.

  • The destaining bags are simple and inexpensive.
  • Drop a destaining bag into your solution,
  • Periodically swirl it around a few times,
  • Let it stand overnight.
  • In the morning, remove the bag and collect for disposal by Health and Safety.
  • Perform UV check of the solution. If it no longer fluoresces, pour the solution down the drain- provided no other hazardous chemicals are present.

Whenever possible, use a less hazardous chemical for the identification of DNA.

Sigma-Aldrich produces a product called REDTAQ DNA Polymerase. It is an inert red tracer conjugated to a polymerase.

 

Other EtBr disposal procedures should be avoided.

The practice of oxidizing ethidium bromide with household bleach is inefficient and may produce additional hazardous compounds.