All radioactive waste must be disposed of in a responsible manner according to applicable regulations. Waste containing long-lived radioisotopes (half-lives > 120 days) is shipped by DRS for final disposal at an off-site facility. Materials contaminated with short-lived nuclides may be stored on campus until indistinguishable from background radiation levels and then disposed of as non-radioactive waste.

Waste that is picked up by DRS for disposal must be segregated, packaged and labeled following the instructions in this section. DRS will not handle any package that does not conform to the requirements or that may present a safety hazard to its personnel or members of the public.

The route of disposal depends on the following factors:

  • Chemical hazards present in the waste
  • Physical phase (liquid or solid)
  • Half-life of isotope

Chemical Hazards Present (Dual Hazard Waste)

When the waste contains more than trace amounts of hazardous chemicals such as regulated metals (As, Ba, Cd, Cr, Pb, Hg, Se, Ag), toxics, or flammables, it is considered a “dual hazard waste” and likely needs to be picked up by DRS. This includes solids (e.g. contaminated lead). Please consult with DRS before submitting a pick-up request. When submitting the request in the DRS Waste Management App, find the UI # of the chemicals present. Identify the waste as radioactive by checking the appropriate box on the form. Add the following information in the description:

  • Permit #
  • Radioisotope
  • Activity
  • Result of a contamination survey on the outside of the package (see section below)

Toluene and xylene-based liquid scintillation cocktails and some HPLC fluids fall into this category. The liquids need to be free of all filterable solids. Collect such liquid waste in spill-proof, sturdy plastic containers no larger than 10L capacity and use a 60-mesh metal screen for filtering.

When collecting liquid waste, pay attention to potential chemical incompatibilities. Incompatible chemicals can generate gases that may cause the container to rupture and potentially may be toxic (e.g. cyanides or azides in acids, tissues digested in nitric acid). The waste generator must ensure that chemical reactions will not occur in liquid waste containers.

Be aware that dual hazard waste can incur high disposal costs and should therefore be minimized as much as possible. If your research will generate large amounts of dual hazard waste, please contact DRS for consultation before you begin the experiments.

If the only chemical hazard is an organic solvent and the amount is small (mL range), the solution may be poured onto absorbent material (pads, cat litter) and dried inside a fume hood. The dried material can then be submitted as radioactive dry debris (see section below).

Liquids Without Chemical Hazards Present (Sewer Disposal)

Aqueous waste containing only water-soluble or dispersible non-hazardous chemical components may be disposed of through the sanitary sewer (sink) if the concentration is below a relevant limit. Most water-soluble scintillation cocktails fall under this category. Use a sink designated for this purpose and adjust the pH to between 6 and 10 before disposal. The concentration limits are shown below:

Radioisotope

Concentration limit (μCi/mL)

H-3

1 x 10-2

C-14

3 x 10-4

P-32

9 x 10-5

P-33

8 x 10-4

S-35

1 x 10-3

I-125

2 x 10-5

I-131

1 x 10-5

Other radionuclide concentration limits can be found in Title 10, Code of Federal Regulations, Part 20, Appendix B, Table 3.

To request a sewer disposal, enter the activity to be disposed of in the DRS database under “Sewer Disposal” and click “Initiate Disposal”. The inventory will be adjusted accordingly once the request is approved.

Water-insoluble liquids or aqueous solutions in excess of the concentrations specified above must not be released into the sewage system. The liquid must either be held for decay or solidified and submitted as dry debris (see next section). Consult DRS about unusual circumstances.

Solids Without Chemical Hazards (Dry Debris)

Dry debris consists of items contaminated with radioisotopes, such as gloves, pipette tips, paper, etc. It cannot contain any freestanding liquids, hazardous chemicals including lead, sharps, or animal carcasses or tissue.

Segregate dry waste by radionuclide half-life (< 120 days and > 120 days) and keep wastes containing tritium (H-3) and carbon-14 (C-14) segregated from other long-lived isotopes.

Collect dry debris in containers labeled with the radiation hazard symbol, the radioisotope identity, and the words “Caution–Radioactive Materials”. Containers must be lined with plastic bags with a thickness of at least four mils of low-density polyethylene (LDPE), clear or transparent yellow in color, and bearing the radiation hazard symbol. Individual bags should be no greater than 30 gallons in volume. Laboratories are responsible for providing their own disposal containers and bags.

Submit dry debris in the DRS Waste Management App and select UI # 6 for short-lived radioisotopes (half-life < 120 days) and UI # 7 for long-lived radioisotopes (half-life > 120 days).

Identify the waste as radioactive by checking the appropriate box on the form. Add the following information in the description:

  • Permit #
  • Radioisotope
  • Activity
  • Result of a contamination survey on the outside of the package (see section below)

Scintillation Vials and Other Glassware

Empty liquid scintillation counting vials or other glassware that contained media with a concentration of C-14 or H-3 less than 0.05 micro-Curies per milliliter (μCi/mL) need not be decontaminated and should be disposed of with the regular, non-radioactive waste. Ensure that vials have been properly emptied and “radioactive material” labels have been removed or defaced.

Empty vials that contained media with a concentration of C-14 or H-3 above 0.05 micro-Curies per milliliter (μCi/mL) or any other radioisotopes can be:

  • Decontaminated by washing. Count a representative sample of the wash water to determine effectiveness. Decontamination is successful when the average count rate is less than twice the background level. Wash water may be disposed of according to section “Liquids without chemical hazards”
  • Disposed of in dry debris (see previous section). Make sure the glassware is completely empty and dried.

Most glass items (e.g., test tubes, dishes) can be decontaminated and re-used after routine washing or an overnight soaking with an industrial-strength detergent.

Radioactive Sharps

Sharps require special precautions and handling. When the following items have come into contact with radioisotopes, dispose of them in Sharps Disposal Containers (SDCs) that bear a Caution–Radioactive Materials label listing isotope and date:

  • Needles and syringes,
  • Pasteur pipettes,
  • Scalpels and razor blades,
  • Microscope slides and coverslips;
  • Broken glassware.

Sharps containers are closable, puncture-resistant, leak-proof on the sides and bottoms, and are typically available in 1-quart, 2-gallon, and 8-gallon sizes.

Most glassware, such as liquid scintillation vials and test tubes, is easily decontaminated as described above and should not be routinely discarded as sharps.

When sharps containers are full, request a pick up in the DRS Waste Management App

Animal Carcasses

Radioactive materials used in animals must be addressed on a case-by-case basis. Permit Holders who are planning to administer radioactive materials to animals should contact DRS for guidance concerning the disposal of carcasses. DRS will review the administration of radioactive materials to animals during the Institutional Animal Care and Use Committee (IACUC) review.

Animal tissues containing 0.05 µCi or less of H-3, C-14, or I-125 per gram of animal tissue averaged over the weight of the entire animal can be disposed of as if it were not radioactive. However, animal tissue in which radioactive materials have been introduced must not be disposed in a manner that would permit its use either as food for humans or as animal feed, such as rendering.

Contamination Surveys for Waste Pick-Ups

For all radioactive waste items picked up by DRS the outside of the container must be free of contamination. For this reason, a survey of the outside of the container is required and the result must be entered into the pick-up request.

To perform the survey, moisten a piece of filter paper or a cotton swab with water or alcohol. Wipe an area of approximately 100 square centimeters per wipe (4 in x 4 in per wipe) along the outside surface of the bag or container. Multiple wipes may be required for larger containers. Count the wipes with a suitable detector (see below) and compare with the background count. Record the container cpm as the net count rate (gross cpm – background cpm). The container cpm should be less than two times the background count rate. If it is not, either decontaminate the outside of the bag or place the contaminated bag inside a clean bag and re-survey.

Suitable detectors:

  • Low-energy beta (H-3, C-14, or S-35): Liquid Scintillation Counter
  • High-energy beta (e.g. P-32): Geiger Counter
  • Gamma (e.g., I-125, I-131): NaI Scintillation Counter.

See Contamination Surveys for more details on survey procedures.

Last Update: 11/20/2020
Updated By: kohl3