3.5 Segregating Radioactive Waste

Segregate radioactive waste by waste type and radioactive half-life. Segregation is the responsibility of the generator, and takes place in the work area where the waste is produced.

Segregate by Half-Life

Radioactive waste is separated into two categories based on half-life.

Short Half-Life = less than 90 days, e.g., I125, P32, P33, S35

Long Half-Life = greater than 90 days, e.g., C14, Cl36, Fe55, H3

Segregate by Waste Type

There are nine general types of radioactive waste generated at The University of Iowa:

  • Aqueous liquid waste
  • Animal carcasses
  • Dry Waste
  • Liquid scintillation vials
  • Mixed waste
  • Radioactive sharps
  • Source vials
  • Sealed sources
  • Lead shielding

Aqueous and Mixed Waste

When organic solvents or other hazardous chemical wastes are contaminated with radioactive material it is known as mixed waste. Mixed waste must always be segregated from aqueous liquid waste.

  • Secondary containment is required.
  • Segregate by half-life and, if possible, by radionuclide.
  • Keep waste containers closed at all times unless adding or removing waste.
  • Do not mix solvents or other chemically hazardous liquid waste with water.
  • Do not put solid material in liquid waste containers.
  • Avoid overfilling radioactive waste containers – leave at least 3 inches of headspace.
  • Do not mark liquid waste containers supplied by EHS. If labeling is necessary, use tape.
  • Prior to pickup by EHS, tightly secure container cap, affix a radioactive label to the container, and place the radioactive waste tag under the bottle handle.

Animal Carcass Waste

Animal carcasses also include animal body parts, excreta, and bedding.

  • Double-bag using strong polyethylene bags.
  • Package in as small a volume as possible.
  • Add coagulants or absorbents to reduce liquids.
  • Bags should not be punctured and outer bag must be free from blood.
  • Securely close and seal bags with tape. Complete the radioactive waste tag prior to pickup by EHS.
  • Larger animals may need to be cut into smaller parts.

Dry Waste

Only paper, plastic, and unbroken glass should be placed in dry waste containers. Do not place liquids, lead, needles, razors, broken glass, or other sharps in dry waste containers.

  • EHS supplies containers.
  • Segregate by half-life. Orange label = <90 days half-life. Red label = >90 days half life.
  • Do not overfill containers. Lid must fit snugly to the top of container.
  • Deface/obliterate all radioactive symbols and wording on any items placed into a dry waste container.
  • Do not put liquids, lead, or sharps into dry waste containers.
  • Do not place items in black or colored bags prior to placing inside a dry waste container.

Prior to pickup by EHS, secure the liner and seal with tape. Complete the radioactive waste tag and affix it to the lid of the radioactive waste container.

Liquid Scintillation Vials Waste

Only LSC vials are to be placed in liquid scintillation vial waste containers. Do not place source vials in liquid scintillation vial waste containers.

  • Segregate C14 and H3LSC vials in one container and place all other radionuclide LSC vials in another.
  • Use biodegradable liquid scintillation cocktail, such as Econosafe or Ready Safe, whenever possible.
  • Avoid overfilling liquid scintillation vial waste containers. Lid must fit snugly on the top of the container.

Prior to pickup by EHS, complete the radioactive waste tag and affix it to the lid of the waste container.

Radioactive Sharps Waste

Radioactive sharps are to be placed only into sharps containers – not dry waste containers.

  • Collect only in containers designed to hold sharps. These are available from Biochem Stores or General Stores.
  • Affix a radioactive warning label to any sharps container used to dispose of radioactive waste.
  • Do not overfill containers.
  • Segregate radioactive sharps by half-life.

Prior to pickup by EHS, tape the lid securely to container, and complete the radioactive waste tag and affix to the sharps container.

Source Vials

  • Vials containing liquid are not to be placed in radioactive waste containers. Attach a tag directly to the source vial and shield, prior to pickup by EHS.
  • Empty vials must have the label and markings obliterated, and must be removed from lead shielding. Dispose of empty vials in the radioactive dry waste.

Sealed Sources

Do not dispose of licensed or generally licensed sealed sources in any EHS radioactive waste container. Sealed sources do not require further packaging if they are not leaking. If a sealed source is leaking, contact the Radiation Protection Section of EHS at 335-8501 for assistance.

Lead Shielding

Do not place lead shielding in radioactive waste containers. To prepare shielding for pickup by EHS:

  • Remove from outer plastic containers, if applicable.
  • Perform a contamination survey.
  • Complete and attach a radioactive waste tag.

Do not accumulate large quantities of lead in your lab.