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Biological Waste

Ethidium Bromide (EtBr) Waste

Ethidium Bromide Ethidium bromide is a material that has become commonly used in biology laboratories for DNA staining. Since the history of laboratory use for this substance is relatively new, its disposal is not highly regulated. However, studies have shown EtBr to be a possible carcinogen, teratogen, and mutagen. Therefore, please take the initiative in your lab to properly dispose of this material.

Electrophoresis gels:

  • Gels of any concentration may be placed in biohazard boxes with other regulated medical waste.
  • Cardboard biohazard boxes must be lined with approved red biohazard bags.
  • Biohazard boxes, as well as bags, are to be securely sealed and marked with the primary investigator’s name and room number.
  • Biohazard boxes may be placed in the hallway for pickup every Wednesday after 12 noon.
  • Biohazard boxes of any size are not to exceed 50 lbs.
  • For supplies or questions regarding packaging procedure, dial ext. 14136 and leave a message.

Stock solutions:

  • Option 1: Bleach converts EtBr to the physiologically inactive product 2-carboxybenzophenone, though the effectiveness of this practice is somewhat controversial.
    • Combine household bleach with EtBr solution in a 1:10 ratio.
    • Stir at room temperature, and allow the mixture to sit for at least 4 hours, overnight if possible.
    • UV light may be used to check for presence of EtBr. If the mixture fluoresces, EtBr is still present. Active mixtures must be retreated.
    • Inactivated mixtures may be pH neutralized and flushed down the laboratory drain with copious amounts of water.
  • Option 2: EtBr may be chemically treated.
    • For each 100mL of EtBr, combine:
      5% hypophosphoric acid
      12mL of 0.5M Sodium nitrate
    • Stir and allow the mixture to stand for 20 hours.
    • Adjust the pH and discard in laboratory drain with copious amounts of water.
  • Option 3: Charcoal filtration removes contaminants.
    • EtBr solutions may be filtered through activated charcoal, and the filtrate may be flushed down laboratory drains.
    • Several companies, such as VWR, sell funnel kits containing activated charcoal.
    • The Green Bag Kit™, which absorbs contaminant, is available for smaller amounts of stock solution.
    • All spent charcoal filters may be disposed of as regulated medical waste, in lined biohazard boxes. See Regulated Medical Waste for procedures.

Preserved Laboratory Animals and Organs

Examples: Preserved animal carcasses, organs and tissues in preserving solutions

  • Place carcasses, organs, and tissues in durable plastic, liquid impermeable pails or drums.
  • Label above containment with the words “Infectious Waste”, the primary investigator’s name, and the room number.
  • Contact EHS for a pickup.

Regulated Medical Waste: Biohazardous and Infectious

Examples: Materials contaminated or potentially contaminated with animal or human body-fluids and vaccines, glassware and other contaminated items from medical labs

  • Attempt to minimize production of this waste stream, if possible.
  • Materials may be placed in biohazard boxes with other regulated medical waste.
  • Cardboard biohazard boxes must be lined with approved red biohazard bags.
  • Biohazard boxes, as well as bags, are to be securely sealed and marked with the primary investigator’s name and room number.
  • Biohazard boxes may be placed in the corridor for pickup every Wednesday after 12 noon.
  • Biohazard boxes of any size are not to exceed 50 lbs.
  • For supplies or questions regarding packaging procedure, dial ext. 14136 and leave a message.