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University of Pittsburgh

Specific Instruction
for Isotope Research Waste

Dry Solid Wastes

Dry solid wastes include contaminated paper, gloves, padding, plastic, and glass associated with radioactive materials work, residual solid radioactive materials, contaminated building debris, etc.

Dry Waste Dry solid radioactive wastes should be segregated according to isotope and placed into appropriate labeled waste containers lined with RSO-approved yellow plastic bags.

High-activity materials such as columns, gels, and residual stock vials should be packaged in a separate bag.

Aspirate or dump all liquids from containers prior to disposal. Small residual amounts of liquids are permitted if there is sufficient absorbent material in the bag.

Solidified liquids may be put in the dry solid waste container.


SharpsAll broken glassware, needles, scalpel blades, glass pipettes, and other items that can penetrate the waste bags should be placed into a sharps container for disposal. Do not recap, bend, remove, or clip needles. Sharps containers should be labeled with a Caution Radioactive Material label.

When filled or otherwise ready for disposal, these containers should be closed securely and then placed in a yellow waste bag as dry solid waste.

Unused Material in Stock Vials

Stock vials containing nuclides with half lives of less than 60 days (P-33, P-32, Tc-99m, PET isotopes, Cr-51, I-125) may be disposed of as dry solid waste.

Unused in Stock VialsStock vials containing nuclides with half-lives greater than 60 days (C-14, H-3, S-35) should be placed in yellow bags with no other materials. The actual residual activity in the vial should be marked on the label.

Lead Metal

Lead containers and shielding materials must be packaged separately from other solid wastes. Empty containers should be bagged with the lids or caps detached. Vials of radioactive material MAY be left in the lead container to provide shielding for any residual activity. The remaining activity must be clearly marked on the waste tag. If large lead objects such as contaminated shielding bricks are involved, please contact the Radiation Safety Office for instructions.

Volatile, Reactive Residual Chemical Wastes
(EPA mixed wastes)

Wastes containing residual hazardous chemicals must be minimized and handled in accordance with all applicable regulations. Specific disposal direction must be obtained from the Radiation Safety Office PRIOR to generating these types of waste.

Liquid Scintillation Fluid Waste

Scintillation Fluid WasteVials, tubes, or other containers used with or containing solutions used for liquid scintillation counting constitute liquid scintillation wastes.

Researchers must use plastic scintillation vials and non-hazardous biodegradable scintillation media, unless otherwise specifically authorized by the Radiation Safety Office.

Scintillation wastes are not to be disposed of by pouring down the drain.

Tightly cap each vial.

Segregate vials by isotope; however, vials containing only H-3 or C-14 may be intermingled. Vials containing lab survey smears may be intermingled with any isotope.

If available, scintillation vials should be replaced into the original cardboard trays or cartons. The Radiation Safety Office will accept a complete carton of trays if it is taped closed and a completed waste tag is applied. Smaller quantities of vials may be packed one or two "flats" per bag, closed and labeled. Mini-vials and bulk tubes should be placed into a yellow plastic bag with an absorbent paper pad or several paper towels to absorb minor leakage. 96 well plates should be wrapped in an absorbent pad.

Liquid Waste

Any liquid, other than liquid scintillation fluids, containing dissolved or suspended radioactive materials constitutes liquid radioactive waste. Liquid wastes can be classified into three basic groups: low-level aqueous/water-soluble wastes, high-level aqueous/water-soluble wastes, and non-aqueous wastes (EPA Mixed Waste). Storage of large volumes of free liquid wastes within the laboratory is strongly discouraged.


Aqueous or water-soluble wastes excluded from sink disposal due to their activity or other characteristics, such as alpha emitters, must be solidified or absorbed with an approved media. Wide-mouth plastic containers containing approved solidification media are available through the Radiation Safety Office.

  1. Carefully pour the liquid into the container containing absorbent media.
  2. Record the activity on the container or a log sheet.
  3. For disposal, tightly cap the jug and place it in a yellow plastic bag. (Absorbed liquid wastes may be disposed of with higher-level dry solid wastes.)
  4. Label the bag with the authorized user's name, the isotope, the estimated activity, and the date of closure.

Non-aqueous Wastes (EPA mixed waste)

Most non-aqueous liquid wastes are excluded from sink disposal due to their insolubility or other characteristics. They must be packaged in accordance with both NRC and EPA hazardous waste regulations. Specific disposal direction must be obtained from the Radiation Safety Office PRIOR to generating these types of waste. In most cases, care must be taken to minimize the volume of waste generated.

Bulk Liquids

Bulk LiquidSome processes, such as HPLC purification or flow-through scintillation counters may generate bulk volumes (> 1 liter) of radioactive liquid waste. Prior to generation, the Radiation Safety Office should be consulted.

  1. Segregate the liquids by chemical and radionuclide.
  2. Use a container which is compatible with the chemicals being collected.
  3. Provide secondary containment when appropriate.
  4. Try to minimize the volume of waste generated.
  5. Clearly label the container with the chemical content and radionuclide.

Sealed Sources

Sealed sources are Sealed Source devices containing radioactive material which are engineered by encapsulation to prevent the distribution of loose material for the life of the device. They may be received as a regulated quantity, a generally licensed quantity, as a component in an instrument or device, or as small unregulated check or calibration sources.

Disposal of all sealed sources is by return to the Radiation Safety Office. Ultimately, they may be returned to the manufacturer, held for decay in storage, or disposed of as radioactive waste.

If a piece of laboratory equipment containing a sealed source is to be decommissioned, transferred to another user, or disposed of, the source must be removed first.

Animal Carcasses and other Biological Waste

The carcasses of research animals used with radioactive materials and any solid or liquid radioactive waste containing significant quantities of tissue or excreta are classified as biological wastes.

These wastes require special handling and packaging in order to meet disposal criteria. As such they MUST BE SEGREGATED from other waste streams and properly identified.

Animal Carcasses, Organs or Tissues

  1. The remains of experimental animals, organs, or tissues to which radioactive materials have been administered should be placed in yellow plastic bags, properly labeled and frozen immediately. These frozen wastes should then to be transferred directly to a designated storage freezer or to a waste processing area attended by Radiation Safety personnel.
  2. When using C-14 and H-3, whenever possible restrict concentrations to less than 0.05 μCi/gram of animal tissue.
  3. The use of formaldehyde/formalin and other hazardous chemical agents must be restricted. These wastes constitute a mixed waste stream and are very difficult to dispose of. If these agents are to be used, please contact the Radiation Safety Office for special packaging procedures.
  4. Ashes, freeze dried, or otherwise desiccated biological wastes may be disposed of as dry solid waste only if liquids are excluded from the same package.

Other Biological Wastes

Whenever possible, blood, urine and other liquid biological wastes should be disposed of in the sanitary sewer. If not suitable for sanitary sewer disposal, these wastes must be adsorbed with an approved media or otherwise converted to solid form prior to disposal. These materials MAY NOT be disposed of as regular dry solid or absorbed liquid waste.

Peripheral materials associated with animal or tissue work containing significant biological material must be treated as biological waste. This category of waste includes any material which will decompose at room temperature to release gasses, vapors, or fumes which may be hazardous to personnel transporting or otherwise handling these materials.

Animal bedding from radiolabeled animals should be segregated from others wastes when possible. Relatively dry bedding can be disposed of as dry solid waste, clearly labeled as animal bedding on the tag. Highly soiled wet bedding material must be handled like liquid biological waste.

Infectious Waste

Biohazardous wasteWastes containing or contaminated with infectious or biohazardous materials must be treated to the extent practical to allow for safe handling in accord with all applicable regulations. Specific disposal direction must be obtained from Radiation Safety and Biosafety offices PRIOR to generating these types of waste. In most cases, care must be taken to minimize the volume of waste generated.

Treatment prior to disposal may include contact with bleach or other disinfectant agents or sterilization by autoclaving.

Autoclaving is limited to non-volatile materials and may require special contamination monitoring following treatment.

Following disinfection, wastes are handled for disposal according to other waste characteristics as already described.